WorldWideScience

Sample records for aquatic humic acid

  1. Isotherm, kinetic and thermodynamics study of humic acid removal process from aquatic environment by chitosan nano particle

    Directory of Open Access Journals (Sweden)

    Maryam Ghafoori

    2016-09-01

    Full Text Available Background and Aim: Humic substances include natural organic polyelectrolyte materials that formed most of the dissolved organic carbon in aquatic environments. Reaction between humic substances and chlorine leading to formation of disinfection byproducts (DBPs those are toxic, carcinogenic and mutagenic. The aim of this study was investigation of isotherms, kinetics and thermodynamics of humic acid removal process by nano chitosan from aquatic environment. Materials and Methods: This practical research was an experimental study that performed in a batch system. The effect of various parameters such as pH, humic acid concentration, contact time, adsorbent dosage, isotherms, thermodynamics and Kinetics of humic acid adsorption process were investigated. Humic acid concentration measured using spectrophotometer at wave length of 254 nm. Results: The results of this research showed that maximum adsorption capacity of nanochitosan that fall out in concentration of 50 mg/l and contact time of 90 minutes was 52.34 mg/g. Also, the maximum adsorption was observed in pH = 4 and adsorbent dosage 0.02 g. Laboratory data show that adsorption of humic acid by nanochitosan follow the Langmuir isotherm model. According to result of thermodynamic study, entropy changes (ΔS was equal to 2.24 J/mol°k, enthalpy changes (ΔH was equal to 870 kJ/mol and Gibbs free energy (ΔG was negative that represent the adsorption process is spontaneous and endothermic. The kinetics of adsorption has a good compliant with pseudo second order model. Conclusion: Regarding to results of this study, nano chitosan can be suggested as a good adsorbent for the removal of humic acids from aqueous solutions.

  2. Coating carbon nanotubes with humic acid using an eco-friendly mechanochemical method: Application for Cu(II) ions removal from water and aquatic ecotoxicity.

    Science.gov (United States)

    Côa, Francine; Strauss, Mathias; Clemente, Zaira; Rodrigues Neto, Laís L; Lopes, Josias R; Alencar, Rafael S; Souza Filho, Antônio G; Alves, Oswaldo L; Castro, Vera Lúcia S S; Barbieri, Edison; Martinez, Diego Stéfani T

    2017-12-31

    In this work, industrial grade multi-walled carbon nanotubes (MWCNT) were coated with humic acid (HA) for the first time by means of a milling process, which can be considered an eco-friendly mechanochemical method to prepare materials and composites. The HA-MWCNT hybrid material was characterized by atomic force microscopy (AFM), scanning electron microscopies (SEM and STEM), X-ray photoelectron spectroscopy (XPS), termogravimetric analysis (TGA), and Raman spectroscopy. STEM and AFM images demonstrated that the MWCNTs were efficiently coated by the humic acid, thus leading to an increase of 20% in the oxygen content at the nanotube surface as observed by the XPS data. After the milling process, the carbon nanotubes were shortened as unveiled by SEM images and the values of ID/IG intensity ratio increased due to shortening of the nanotubes and increasing in the number defects at the graphitic structure of carbon nanotubes walls. The analysis of TGA data showed that the quantity of the organic matter of HA on the nanotube surface was 25%. The HA coating was responsible to favor the dispersion of MWCNTs in ultrapure water (i.e. -42mV, zeta-potential value) and to improve their capacity for copper removal. HA-MWCNTs hybrid material adsorbed 2.5 times more Cu(II) ions than oxidized MWCNTs with HNO 3 , thus evidencing that it is a very efficient adsorbent material for removing copper ions from reconstituted water. The HA-MWCNTs hybrid material did not show acute ecotoxicity to the tested aquatic model organisms (Hydra attenuata, Daphnia magna, and Danio rerio embryos) up to the highest concentration evaluated (10mgL -1 ). The results allowed concluding that the mechanochemical method is effective to coat carbon nanotubes with humic acid, thus generating a functional hybrid material with low aquatic toxicity and great potential to be applied in environmental nanotechnologies such as the removal of heavy metal ions from water. Copyright © 2017 Elsevier B.V. All rights

  3. Humic acid protein complexation

    Science.gov (United States)

    Tan, W. F.; Koopal, L. K.; Weng, L. P.; van Riemsdijk, W. H.; Norde, W.

    2008-04-01

    Interactions of purified Aldrich humic acid (PAHA) with lysozyme (LSZ) are investigated. In solution LSZ is moderately positively and PAHA negatively charged at the investigated pH values. The proton binding of PAHA and of LSZ is determined by potentiometric proton titrations at various KCl concentrations. It is also measured for two mixtures of PAHA-LSZ and compared with theoretically calculated proton binding assuming no mutual interaction. The charge adaptation due to PAHA-LSZ interaction is relatively small and only significant at low and high pH. Next to the proton binding, the mass ratio PAHA/LSZ at the iso-electric point (IEP) of the complex at given solution conditions is measured together with the pH using the Mütek particle charge detector. From the pH changes the charge adaptation due to the interaction can be found. Also these measurements show that the net charge adaptation is weak for PAHA-LSZ complexes at their IEP. PAHA/LSZ mass ratios in the complexes at the IEP are measured at pH 5 and 7. At pH 5 and 50 mmol/L KCl the charge of the complex is compensated for 30-40% by K +; at pH 7, where LSZ has a rather low positive charge, this is 45-55%. At pH 5 and 5 mmol/L KCl the PAHA/LSZ mass ratio at the IEP of the complex depends on the order of addition. When LSZ is added to PAHA about 25% K + is included in the complex, but no K + is incorporated when PAHA is added to LSZ. The flocculation behavior of the complexes is also different. After LSZ addition to PAHA slow precipitation occurs (6-24 h) in the IEP, but after addition of PAHA to LSZ no precipitation can be seen after 12 h. Clearly, PAHA/LSZ complexation and the colloidal stability of PAHA-LSZ aggregates depend on the order of addition. Some implications of the observed behavior are discussed.

  4. DOC removal paradigms in highly humic aquatic ecosystems.

    Science.gov (United States)

    Farjalla, Vinicius F; Amado, André M; Suhett, Albert L; Meirelles-Pereira, Frederico

    2009-07-01

    Dissolved humic substances (HS) usually comprise 50-80% of the dissolved organic carbon (DOC) in aquatic ecosystems. From a trophic and biogeochemical perspective, HS has been considered to be highly refractory and is supposed to accumulate in the water. The upsurge of the microbial loop paradigm and the studies on HS photo-degradation into labile DOC gave rise to the belief that microbial processing of DOC should sustain aquatic food webs in humic waters. However, this has not been extensively supported by the literature, since most HS and their photo-products are often oxidized by microbes through respiration in most nutrient-poor humic waters. Here, we review basic concepts, classical studies, and recent data on bacterial and photo-degradation of DOC, comparing the rates of these processes in highly humic ecosystems and other aquatic ecosystems. We based our review on classical and recent findings from the fields of biogeochemistry and microbial ecology, highlighting some odd results from highly humic Brazilian tropical lagoons, which can reach up to 160 mg C L(-1). Highly humic tropical lagoons showed proportionally lower bacterial production rates and higher bacterial respiration rates (i.e., lower bacterial growth efficiency) than other lakes. Zooplankton showed similar delta(13)C to microalgae but not to humic DOC in these highly humic lagoons. Thus, the data reviewed here do not support the microbial loop as an efficient matter transfer pathway in highly humic ecosystems, where it is supposed to play its major role. In addition, we found that some tropical humic ecosystems presented the highest potential DOC photo-chemical mineralization (PM) rates reported in the literature, exceeding up to threefold the rates reported for temperate humic ecosystems. We propose that these atypically high PM rates are the result of a joint effect of the seasonal dynamics of allochthonous humic DOC input to these ecosystems and the high sunlight incidence throughout the year

  5. Ultrafiltration technique in conjunction with competing ligand exchange method for Ni–humics speciation in aquatic environment

    Digital Repository Service at National Institute of Oceanography (India)

    Chakraborty, P.; Boissel, M.; Reuillon, A.; Babu, P.V.R.; Parthiban, G.

    The combination of ultrafiltration technique with competing ligand exchange method provides a better understanding of interactions between Ni and different molecular weight fractions of humic acid (HA) at varying pH in aquatic environment...

  6. Application of the NICADonnan model for proton, copper and uranyl binding to humic acid

    NARCIS (Netherlands)

    Saito, T.; Nagasaki, S.; Tanaka, S.; Koopal, L.K.

    2004-01-01

    Humic acids are natural organic materials that play an important role in the migration of heavy metal and actinide ions in aquatic and soil systems. In the present study, the binding of protons, copper ions and uranyl ions to the purified Aldrich humic acid (PAHA) is investigated and the results are

  7. Precipitation of humic acid with divalent ions

    DEFF Research Database (Denmark)

    Andersen, Niels Peder Raj; Mikkelsen, Lene Haugaard; Keiding, Kristian

    2001-01-01

    The aim of this study is to investigate precipitation proper-ties of humic acid (HA). This is done by studying a commercial available humic acid salt (HA) from which a phase diagram is established by adding various amounts of BaCl2 to different concentrations of HA at pH 5.5. The phase diagram sh...

  8. Amino acids in the sedimentary humic and fulvic acids

    Digital Repository Service at National Institute of Oceanography (India)

    Sardessai, S.

    Humic and fulvic acids isolated from a few sediment samples from Arabian Sea and Bay of Bengal were analysed for total hydrolysable amino acids concentration and their composition. The amono acids content of fulvic acids was higher than in the humic...

  9. Iodine binding to humic acid.

    Science.gov (United States)

    Bowley, H E; Young, S D; Ander, E L; Crout, N M J; Watts, M J; Bailey, E H

    2016-08-01

    The rate of reactions between humic acid (HA) and iodide (I(-)) and iodate (IO3(-)) have been investigated in suspensions spiked with (129)I at concentrations of 22, 44 and 88 μg L(-1) and stored at 10 °C. Changes in the speciation of (129)I(-), (129)IO3(-) and mixed ((129)I(-) + (129)IO3(-)) spikes were monitored over 77 days using liquid chromatography inductively coupled plasma mass spectrometry (LC-ICP-MS). In suspensions spiked with (129)I(-) 25% of the added I(-) was transformed into organic iodine (Org-(129)I) within 77 days and there was no evidence of (129)IO3(-) formation. By contrast, rapid loss of (129)IO3(-) and increase in both (129)I(-) and Org-(129)I was observed in (129)IO3(-)-spiked suspensions. However, the rate of Org-(129)I production was greater in mixed systems compared to (129)IO3(-)-spiked suspensions with the same total (129)I concentration, possibly indicating IO3(-)I(-) redox coupling. Size exclusion chromatography (SEC) demonstrated that Org-(129)I was present in both high and low molecular weight fractions of the HA although a slight preference to bond with the lower molecular weight fractions was observed indicating that, after 77 days, the spiked isotope had not fully mixed with the native (127)I pool. Iodine transformations were modelled using first order rate equations and fitted rate coefficients determined. However, extrapolation of the model to 250 days indicated that a pseudo-steady state would be attained after ∼200 days but that the proportion of (129)I incorporated into HA was less than that of (127)I indicating the presence of a recalcitrant pool of (127)I that was unavailable for isotopic mixing. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Metalion-humic acid nanoparticle interactions

    DEFF Research Database (Denmark)

    Town, Raewyn M.; van Leeuwen, Herman P.

    2016-01-01

    Purely Donnan type models for electrostatic binding by humic acid (HA) nanoparticles are shown to be physically incomplete. To describe the extent of ion binding by HA, such models need to invoke parameters that are not consistent with experimental observations. These disparate parameters include...... binding by humic acid nanoparticles. The extent of Ca2+-HA association can be adequately described solely in terms of electrostatics only, including counterion condensation in the intraparticulate double layer in addition to Donnan partitioning in the remainder of the particle body. The binding of Cd...

  11. Comparison of humic acids production by Trichoderma viride and ...

    African Journals Online (AJOL)

    FEA

    2014-02-24

    Feb 24, 2014 ... The remarkable properties of humic acids have generated a broad spectrum of applications in pharmaceutical, cosmetic and agricultural fields, and encouraged fermentation studies focusing on humic acids production. This work compares the humic acids production of Trichoderma (viride and.

  12. Acid dissociation characteristics of humic acids

    International Nuclear Information System (INIS)

    Tochiyama, Osamu; Sakakibara, Tetsuro; Inoue, Yasushi

    1995-01-01

    Based on the results from potentiometric titrations carried out on polyacrylic acid and some commercially available humic acids, the equation for the proton dissociation of weak polymeric acids is proposed to be K app (H + )α/(1-α) = K 1/2 {(1-α)/α}((Na + )/(Na + ) s ), where α is the degree of dissociation, K 1/2 is the dissociation constant at α = 1/2, and the brackets with subscript s denote the concentration at the surface of the polymer. This equation has been derived on the assumptions: (i) Each polymer molecule is a polybasic acid (H N R N ) having different acidic sites with K values from K 1 to K N . (ii) Binding energies of protons on these sites are all equal. (iii) The ratios of the dissociation constants of H N-i R N i- and H N-j R N j- is expressed by K i /K j = {(N-i+1)/i}/{(N-j+1)/j} since the probabilities to release or bind a proton are proportional to the numbers of protons or numbers of available anionic sites on the polymer. (iv) The effective concentration of protons at the surface of the polymer ((H + ) s ) is related by (H + ) s /(H + ) = (Na + ) s /(Na + ), where (Na + ) s can be estimated by the relation, (Na + ) s = (Cl - ) s + (R - ) s (where (R - ) s Σi(H N-i R N i- )). This leads to (Na + ) s ≅ (Cl - ) s , which in turn leads to (Na + ) s ≅ (Na + ) at high ionic strength and (Na + ) s ≅ (R - ) s = C R α at low ionic strength. (author)

  13. Characteristics of humic and fulvic acids in Arabian Sea sediments

    Digital Repository Service at National Institute of Oceanography (India)

    Sardessai, S.

    Humic and fulvic acids isolated from some of the shelf, slope and offshore sediments of the Arabian Sea were studied. The molecular weight, functional groups, elemental composition and infrared spectra were examined. Humic substances, dominated...

  14. Characterization of reference and site specific humic acids

    International Nuclear Information System (INIS)

    Kim, J.I.; Buckau, G.

    1988-11-01

    As a contribution to the interlaboratory exercise for the complexation of humic acid and colloid generation (COCO-Club activities) in the CEC project MIRAGE-II, the characterization of selected humic acids have been carried out at TU Muenchen, regarding their elemental compositions, inorganic impurities, spectroscopic properties, size distributions and proton exchange capacities. The commercial humic acid (Na salt) from Aldrich Co. is purified to a protonated form and used as reference material. Furthermore two humic acids extracted from groundwaters from Gorleben (FRG) and Boom Clay (B) are purified to protonated forms and taken as site specific materials. These three humic acids, together with the original Na salt from Aldrich Co., are included in the present characterization exercise. The results of characterization provide basic knowledge supporting the forthcoming study of complexation of actinides and fission products with humic acid and their migration processes in the geosphere. (orig.)

  15. Adsorption of humic acid on acid-activated Greek bentonite.

    Science.gov (United States)

    Doulia, Danae; Leodopoulos, Ch; Gimouhopoulos, K; Rigas, F

    2009-12-15

    The adsorption of humic acid on bentonite from Milos Island (Greece) acid-treated with dilute H(2)SO(4) solutions over a concentration range between 0.25 and 13M has been studied. Bentonite activated with 3M sulfuric acid (AAS) showed a higher efficiency in removing humic acid from aqueous solutions and was selected for further investigation. The specific surface area of acid-activated bentonite was estimated using the methylene blue adsorption method. The morphology of untreated, activated, and HA-sorbed bentonite was studied under scanning electron microscope (SEM). The effects of contact time, adsorbate concentration, adsorbent dose, and temperature on the adsorption of humic acid onto bentonite activated with 3M H(2)SO(4) were studied using a batch adsorption technique. Acidic pH and high ionic strength proved to be favorable for the adsorption efficiency. Pseudo-first-order, pseudo-second-order, and intraparticle diffusion models were used to describe the kinetic data and the rate constants were evaluated. The experimental isotherm data were analyzed using Langmuir, Freundlich, and Temkin equations and the isotherm constants were determined. Thermodynamic parameters (DeltaH(o), DeltaS(o), and DeltaG(o)) of adsorption of humic acid onto acid-activated bentonite with 3M sulfuric acid were also evaluated.

  16. Properties and structure of raised bog peat humic acids

    Science.gov (United States)

    Klavins, Maris; Purmalis, Oskars

    2013-10-01

    Humic substances form most of the organic components of soil, peat and natural waters, and their structure and properties differ very much depending on their source. The aims of this study are to characterize humic acids (HAs) from raised bog peat, to evaluate the homogeneity of peat HAs within peat profiles, and to study peat humification impact on properties of HAs. A major impact on the structure of peat HAs have lignin-free raised bog biota (dominantly represented by bryophytes of different origin). On diagenesis scale, peat HAs have an intermediate position between the living organic matter and coal organic matter, and their structure is formed in a process in which more labile structures (carbohydrates, amino acids, etc.) are destroyed, while thermodynamically more stable aromatic and polyaromatic structures emerge as a result of abiotic synthesis. However, in comparison with soil, aquatic and other HAs, aromaticity of peat HAs is much lower. Comparatively, the raised bog peat HAs are at the beginning of the transformation process of living organic matter. Concentrations of carboxyl and phenolic hydroxyl groups change depending on the peat age and decomposition degree from where HAs have been isolated, and carboxylic acidity of peat HAs increases with peat depth and humification degree.

  17. Hydrophilic interaction liquid chromatography method for measuring the composition of aquatic humic substances

    KAUST Repository

    Wang, Renqi

    2015-01-01

    A hydrophilic interaction liquid chromatography (HILIC) method was developed to measure the composition of humic substances from river, reservoir, and treated wastewater based on their physicochemical properties. The current method fractionates the humic substances into four well-defined groups based on parallel analyses with a neutral and a cationic HILIC column, using mobile phases of varied compositions and pH. The results indicate that: (i) the proportion of carboxylic acids in the humic substances from terrestrial origins is less than half of that from treated wastewater (Jeddah, KSA), (ii) a higher content of basic compounds was observed in the humic substances from treated wastewater and Ribou Reservoir (Cholet, France) than in the sample from Loire River (France), (iii) a higher percentage of hydrophobic macromolecules were found in the humic substances from Loire River than in the other samples, and (iv) humic substances of treated wastewater contained less ionic neutral compounds (i.e., pKa 5-9) than the waters from terrestrial origins. The physicochemical property disparity amongst the compounds in each humic substances sample was also evaluated. The humic substances from the lightly humic Loire river displayed the highest disparity, whereas the highly humic Suwannee river (Georgia, USA) showed the most homogeneous humic substances.

  18. Stability constant of the lanthanum complex with humic acid

    International Nuclear Information System (INIS)

    Jimenez R, M.; Solache R, M. J.

    2008-01-01

    The work described here is a study on the formation of trivalent lanthanum complex with humic acid. Commercial humic acid was purified and then characterized by various analytical techniques. The stability constant determined by a radiochemical method has a worth of log β La , AHA = 13.6. (Author)

  19. Characterization of metal/humic acid systems by Capillary Electrophoresis

    NARCIS (Netherlands)

    Staden JJ van; Hoop MAGT van den; Cleven R; LAC

    2000-01-01

    Metal-humic acid systems have been characterised applying Capillary Electrophoresis (CE). Appropriate experimental conditions with respect to carrier electrolyte, pH range, salt concentration, humic acid concentration and the applied potential, have been optimised. The influence of multivalent metal

  20. Phosphorus and humic acid application alleviate salinity stress of ...

    African Journals Online (AJOL)

    Humic acid is a commercial product that contains many elements which improve the soil fertility and increase the availability of nutrient elements. It consequently affects plant growth and yield and ameliorates the deleterious effects of salt stress. The objective of the study was to determine the effect of humic acids and ...

  1. Complexes of the antimicrobial ciprofloxacin with soil, peat, and aquatic humic substances.

    Science.gov (United States)

    Aristilde, Ludmilla; Sposito, Garrison

    2013-07-01

    Natural organic matter (NOM) is implicated in the binding of antibiotics by particles in soils and waters. The authors' previous computational study revealed structural rearrangement of both hydrophilic and hydrophobic moieties of NOM to favor H-bonding and other intermolecular interactions, as well as both competition with ion-exchange reactions and bridging interactions by NOM-bound divalent cations. The importance of these interactions was investigated using fluorescence-quenching spectroscopy to study the adsorption of ciprofloxacin (Cipro), a fluoroquinolone antibiotic, on 4 reference humic substances (HSs): Elliott soil humic acid (HA), Pahokee peat HA, and Suwannee river HA and fulvic acid. A simple affinity spectrum HS model was developed to characterize the cation-exchange capacity and the amount of H-bond donor moieties as a function of pH. The adsorption results stress the influence of both pH conditions and the type of HS: both soil HA and peat HA exhibited up to 3 times higher sorption capacity than the aquatic HS at pH ≥ 6, normalizing to the aromatic C content accounted for the differences among the terrestrial HS, and increasing the concentration of divalent cations led to a decrease in adsorption on aquatic HA but not on soil HA. In addition, the pH-dependent speciation models of the Cipro-HS complexes illustrate an increase in complexation due to an increase in deprotonation of HS ligands with increasing pH and, at circumneutral and alkaline pH, enhanced complexation of zwitterionic Cipro only in the presence of soil HA and peat HA. The findings of the present study imply that, in addition to electrostatic interactions, van der Waals interactions as facilitated by aromatic structures and H-bond donating moieties in terrestrial HS may facilitate a favorable binding environment. Environ Toxicol Chem 2013;32:1467-1478. © 2013 SETAC. Copyright © 2013 SETAC.

  2. Characterization of Humic Acid from the River Bottom Sediments of Burigonga: Complexation Studies of Metals with Humic Acid

    Directory of Open Access Journals (Sweden)

    Mohammad Arifur Rahman

    2010-06-01

    Full Text Available In order to characterize and study of the complexation of humic acid with metal ions, sediment samples were collected from five different places in the Buriganga River. The Humic Acids were extracted with the standard procedure provided by the International Humic Substance Society (IHSS. The extracted Humic Acids were characterized with FTIR, EDX and CHNS analyzer and a comparison between the standard and extracted HA was carried out. High C/N ratios (71.48-87.36 are observed in the CHNS analysis. A complexation study of the Humic Acid with iron (III and cadmium (II was also carried out using EDX, UV-Visible spectrophotometer and AAS techniques. The coagulation behavior was observed with Jar test. From the study, it was found that iron and cadmium could make a complex at pH 6.0 which was confirmed by EDX (Electron Dispersive x-ray.

  3. Interaction of humic acids and humic-acid-like polymers with herpes simplex virus type 1

    Science.gov (United States)

    Klöcking, Renate; Helbig, Björn

    The study was performed in order to compare the antiviral activity against herpes simplex virus type 1 (HSV-1) of synthetic humic-acid-like polymers to that of their low-molecular-weight basic compounds and naturally occurring humic acids (HA) in vitro. HA from peat water showed a moderate antiviral activity at a minimum effective concentration (MEC) of 20 µg/ml. HA-like polymers, i.e. the oxidation products of caffeic acid (KOP), hydrocaffeic acid (HYKOP), chlorogenic acid (CHOP), 3,4-dihydroxyphenylacetic acid (3,4-DHPOP), nordihydroguaretic acid (NOROP), gentisinic acid (GENOP), pyrogallol (PYROP) and gallic acid (GALOP), generally inhibit virus multiplication, although with different potency and selectivity. Of the substances tested, GENOP, KOP, 3,4-DHPOP and HYKOP with MEC values in the range of 2 to 10 µg/ml, proved to be the most potent HSV-1 inhibitors. Despite its lower antiviral potency (MEC 40 µg/ml), CHOP has a remarkable selectivity due to the high concentration of this polymer that is tolerated by the host cells (>640 µg/ml). As a rule, the antiviral activity of the synthetic compounds was restricted to the polymers and was not preformed in the low-molecular-weight basic compounds. This finding speaks in favour of the formation of antivirally active structures during the oxidative polymerization of phenolic compounds and, indirectly, of corresponding structural parts in different HA-type substances.

  4. Interaction of neptunium with humic acid and anaerobic bacteria

    International Nuclear Information System (INIS)

    Kubota, Takumi; Sasaki, Takayuki; Kudo, Akira

    2002-01-01

    Humic acid and bacteria play an important role in the migration of radionuclides in groundwaters. The interaction of neptunium with humic acid and anaerobic bacteria has been investigated by liquid/liquid and solid/liquid extraction systems. For liquid/liquid extraction, the apparent complex formation constant, β α was obtained from the distribution between two phases of neptunium. For solid/liquid extraction, the ratio of sorption to bacteria, K d , was measured. K d of humic acid can be evaluated from β α . The large value of β α and K d means strong interaction of neptunium with organisms. In order to examine the effect of the nature of organism on interaction, the interaction with humic acid was compared to that with non-sterilized or sterilized mixed anaerobic bacteria. The value of β α of humate depended on neptunium ion concentration as well as pH, which showed the effect of polyelectrolyte properties and heterogeneous composition of humic acid. The comparison of interaction with humic acid and bacteria indicated that the K d value of humic acid was larger than that of bacteria and more strongly depend on pH. (author)

  5. Neptunium speciation in humic acid - goethite system

    International Nuclear Information System (INIS)

    Kalmykov, St.; Khasanova, A.; Shcherbina, N.; Perminova, I.; Schafer, T.; Claret, F.; Teterin, Y.

    2007-01-01

    Full text of publication follows. Humic acids (HA) are known to have significant effect on metal ion speciation in the environment and may either enhance or depress their migration ability depending on geochemical conditions. This study deals with Np(V) behaviour in HA-goethite suspension at different pH values. The HA used in this study were enriched in hydroquinone group content that define their redox properties. The sorption of Np(V) by goethite in the presence of HA was studied in batch mode at pHs from 2.5 to 9. It was established that at low pH values the sorption of Np agrees with the sorption of HA by goethite and was significantly higher than in binary Np-goethite system. The scanning transmission X-ray microscopic (STXM) study done at National Synchrotron Light Source (BNL, USA) was used to characterize humic surface coatings on goethite. According to STXM, organic matter 'hot spots' were observed in the central region of goethite particles. These 'hot spots' revealed high amounts of C=C arom and aliphatic structures, whereas edge regions of goethite particles or the cloudy regions around this particle contained lower amounts of these organic functionalities. The particle edge structures and the surrounding of the particle were enriched in oxygen-containing functional groups. The enhanced Np sorption at low pH values was explained by its reduction to tetravalent state with formation of stable Np(IV) humates that was established by Vis-NIR spectrophotometry for binary Np(V)-HA solutions and XPS for ternary Np-HA-goethite system. At pH > 6 neptunium retention by HA-goethite suspension was slightly lower that in the absence of HA that is due to week Np(V) humic complexation in solution. According to STXM no detection of organics on goethite minerals by carbon K-edge measurements was possible and the results might be interpreted as an absence of organic matter sorption on the mineral phases under the conditions of batch-type studies. The absence of Np

  6. Determination of humic and fulvic acids in commercial solid and liquid humic products by alkaline extraction and gravimetric determination

    Science.gov (United States)

    Increased use of humic substances in agriculture has generated intense interest among producers, consumers, and regulators for an accurate and reliable method for quantification of humic (HA) and fulvic acids (FA) in raw ores and products. Here we present a thoroughly validated method, the Humic Pro...

  7. Adsorption of humic acids and trace metals in natural waters

    Science.gov (United States)

    Leung, W. H.

    1982-01-01

    Studies concerning the interactions between suspended hydrous iron oxide and dissolved humic acids and trace metals are reported. As a major component of dissolved organic matters and its readiness for adsorption at the solid/water interface, humic acids may play a very important role in the organometallic geochemistry of suspended sediments and in determining the fate and distribution of trace metals, pesticides and anions in natural water systems. Most of the solid phases in natural waters contain oxides and hydroxides. The most simple promising theory to describe the interactions of hydrous iron oxide interface is the surface complex formation model. In this model, the adsorptions of humic acids on hydrous iron oxide may be interpreted as complex formation of the organic bases (humic acid oxyanions) with surface Fe ions. Measurements on adsorptions were made in both fresh water and seawater. Attempts have been made to fit our data to Langmuir adsorption isotherm. Adsorption equilibrium constants were determined.

  8. Characterization and complexation of humic acids. Part 1

    International Nuclear Information System (INIS)

    Kim, J.L.; Buckau, G.; Klenze, R.; Rhee, D.S.; Wimmer, H.

    1991-01-01

    This paper summarizes the research contributions to the CEC Mirage II project, particularly the research area on complexation and colloids (COCO). The first part of the paper comprises the characterization of humic and fulvic acids from different origins: a commercial product from the Aldrich Co. used as a reference humic acid and site-specific humic acids from Gorleben (Germany), Boom Clay (Belgium) and Fanay Augeres (France) aquifer systems. The second part includes the complexation of trivalent actinides: Am(III) and Cm(III) with various humic acids. A number of different methods have been applied for the complexation study: spectrophotometry, ultrafiltration, laser-induced photo-acoustic spectroscopy (LPAS) and time-resolved laser fluorescence spectroscopy (TRLFS). The evaluation process of complexation constant is discussed extensively and the well consolidated results are presented, which can be directly used for the geochemical modelling of the radionuclide migration

  9. Accumulation of humic acid in DET/DGT gels

    Digital Repository Service at National Institute of Oceanography (India)

    Van der Veeken, P.L.R.; Chakraborty, P.; Van Leeuwen, H.P.

    in Thin film) that these natural complexing agents do enter the gel layer, and that humic acids even appear to accumulate in the gel, with enrichment factors typicallyonthe order of 10. The results have consequences for the interpretation of DGT...

  10. Potentiometric titration and equivalent weight of humic acid

    Science.gov (United States)

    Pommer, A.M.; Breger, I.A.

    1960-01-01

    The "acid nature" of humic acid has been controversial for many years. Some investigators claim that humic acid is a true weak acid, while others feel that its behaviour during potentiometric titration can be accounted for by colloidal adsorption of hydrogen ions. The acid character of humic acid has been reinvestigated using newly-derived relationships for the titration of weak acids with strong base. Re-interpreting the potentiometric titration data published by Thiele and Kettner in 1953, it was found that Merck humic acid behaves as a weak polyelectrolytic acid having an equivalent weight of 150, a pKa of 6.8 to 7.0, and a titration exponent of about 4.8. Interdretation of similar data pertaining to the titration of phenol-formaldehyde and pyrogallol-formaldehyde resins, considered to be analogs for humic acid by Thiele and Kettner, leads to the conclusion that it is not possible to differentiate between adsorption and acid-base reaction for these substances. ?? 1960.

  11. Simultaneous analysis of small organic acids and humic acids using high performance size exclusion chromatography

    NARCIS (Netherlands)

    Qin, X.P.; Liu, F.; Wang, G.C.; Weng, L.P.

    2012-01-01

    An accurate and fast method for simultaneous determination of small organic acids and much larger humic acids was developed using high performance size exclusion chromatography. Two small organic acids, i.e. salicylic acid and 2,3-dihydroxybenzoic acid, and one purified humic acid material were used

  12. Thermodynamics of Molybdate Binding to Humic Acid

    Science.gov (United States)

    Thalhammer, K.; Gilbert, B.

    2016-12-01

    Molybdenum is an essential nutrient for diazotrophic bacteria that use nitrogenase I to fix atmospheric nitrogen in soils into bioavailable forms such as ammonia. This metalloid is released during rock weathering processes and at neutral pH it exists primarily as the soluble oxyanion molybdate, MoO42-. It has been established that molybdate mobility and bioavailability in soils is influenced by sorption to mineral surfaces and complexation by natural organic matter (NOM). The molybdate ion is readily bound by ortho dihydroxybenzene molecules such as catechol and catechol groups in siderophores. Humic acids (HA) found in NOM contain abundant phenolic groups and extended X-ray absorption fine structure (EXAFS) spectroscopy demonstrated that molybdate is bound by catechol-containing molecules in soil organic matter1. However, to our knowledge no quantitative determination of the affinity of molybdate to HA has been reported. We studied the interactions of molybdate with Suwannee River HA using ultraviolet-visible (UV-vis) absorption spectroscopy and isothermal titration calorimetry (ITC) to determine the conditional equilibrium constant for complexation at neutral pH. We further used ITC to investigate the thermodynamic contributions to complexation and the interaction kinetics. Addition of molybdate to HA caused the formation of complexes with UV-vis absorption spectra in good agreement with molybdate-catechol species indicating catechol groups to be the primary ligands in HA. ITC data revealed that binding enthalpies and kinetics were strongly influenced by ionic strength, suggesting a role for macromolecular reorganization driven by metalloid addition. 1. Wichard et al., Nature Geoscience 2, 625 - 629 (2009).

  13. Effects of Salicylic acid and Humic acid on Vegetative Indices of Periwinkle (Catharanthus roseusL.

    Directory of Open Access Journals (Sweden)

    E. Chamani

    2016-07-01

    Full Text Available Introduction: Vinca flower (Catharanthus roseus L. is one of the most important medicinal plants of Apocynaceae (31, 27. Tropical plant native to a height of 30 to 35 centimeters (9 and a perennial shrub which is grown in cold areas for one year (27.One of the plants in the world today as a medicinal plant used the periwinkle plant. Among the 130 indole – terpenoids alkaloids which have been identified in the plant periwinkle vinca alkaloids vincristine and vinblastin are the most important component is used to treat a variety of cancers. Including therapies that are used for a variety of cancer, chemotherapy to help Vinca alkaloids collection (including vincristine and…. Vinblastin as effective member of this category, due to the low percentage of venom and effects at very low doses, is widely used today. These materials are generally formed as inhibitors of mitotic spindle in dividing cells have been identified. Vinblastin with these structural changes in connection kinotokor - microtubules and centrosomes in a dividing cell, the mitotic spindle stop (45.Salicylic acid belongs to a group of phenolic compounds found in plants, and today is widely regarded as a hormone-like substance. These classes of compounds act as growth regulators. Humic substances are natural organic compounds that contain 50 to 90% of organic matter, peat, charcoal, rotten food and non-living organic materials are aquatic and terrestrial ecosystems (2. Materials and Methods: In this experiment, vinca F2 seeds in the mixed 4: 1 perlite and peat moss to the planting trays were sown. The seedlings at the 6-leaf stage were transfered to the main pot (pot height 30 and 25 cm diameter The pots bed soil mix consisting of 2 parts soil to one part sand and one part peat moss (v / v were used and after the establishment of seedlings in pots every two weeks with. Salicylic acid and humic acid concentrations 0 (control, 10, 100, 500 and 1000 mg were treated as a foliar spray

  14. Effects of humic acids on the growth of bacteria

    Science.gov (United States)

    Tikhonov, V. V.; Yakushev, A. V.; Zavgorodnyaya, Yu. A.; Byzov, B. A.; Demin, V. V.

    2010-03-01

    The influence of humic acids of different origins on the growth of bacterial cultures of different taxa isolated from the soil and the digestive tracts of earthworms ( Aporrectodea caliginosa)—habitats with contrasting conditions—was studied. More than half of the soil and intestinal isolates from the 170 tested strains grew on the humic acid of brown coal as the only carbon source. The specific growth rate of the bacteria isolated from the intestines of the earthworms was higher than that of the soil bacteria. The use of humic acids by intestinal bacteria confirms the possibility of symbiotic digestion by earthworms with the participation of bacterial symbionts. Humic acids at a concentration of 0.1 g/l stimulated the growth of the soil and intestinal bacteria strains (66 strains out of 161) on Czapek’s medium with glucose (1 g/l), probably, acting as a regulator of the cell metabolism. On the medium with the humic acid, the intestinal bacteria grew faster than the soil isolates did. The most active growth of the intestinal isolates was observed by Paenibacillus sp., Pseudomonas putida, Delftia acidovorans, Microbacterium terregens, and Aeromonas sp.; among the soil ones were the representatives of the Pseudomonas genus. A response of the bacteria to the influence of humic acids was shown at the strain level using the example of Pseudomonas representatives. The Flexom humin preparation stimulated the growth of the hydrocarbon-oxidizing Acinetobacter sp. bacteria. This effect can be used for creating a new compound with the elevated activity of bacteria that are destroyers of oil and oil products.

  15. Studies of the Tc oxidation states in humic acid solutions

    International Nuclear Information System (INIS)

    Wang Bo; Liu Dejun; Yao Jun

    2010-01-01

    The oxidation state is an important aspect of the speciation of Tc in groundwater that contained organic substances due to it control the precipitation, complexation, sorption and colloid formation behavior of the Tc under HWL geological disposal conditions. In present work, the oxidation states of Tc were investigated using the LaCl 3 coagulation method and solution extraction method in aqueous solutions in which the humic acid concentration range is from 0 to 20 mg L -1 and the Tc (Ⅶ) concentration range is about 10 -8 mol l -1 . The radiocounting of 99 Tc was determined using liquid scintillation spectrometry. The humic acid will influence the radiocounting ratio of 99 Tc apparently, however, the quenching effect can be restrained once keep the volume of the cocktail to about twenty times of the sample volume. The LaCl 3 coagulation methods were carried out for the investigation of Tc oxidation states in humic acid aqueous systems at about pH 8. The tetraphenylarsonium chloride (IPA)-chloroform extraction method was used also simultaneously to investigation the concentrations of Tc (Ⅳ) and Tc (Ⅶ) for the availability of the LaCl 3 precipitation method, and the experimental results demonstrate that tetravalent technetium and pertechnetate concentrations are well agreement with the LaCl 3 precipitation method. These two experimental results demonstrated that Tc (Ⅶ) is very stable in the Tc (Ⅶ)-humic acid system during a 350 days experimental period, and the Tc (Ⅳ) concentrations are very lower, that is indicate that there didn't oxidizing reactions between the Fluka humic acid and Tc (Ⅶ) in aqueous solutions under anaerobic conditions. That is means the presence of humic acids even in anaerobic groundwater is disadvantage for the retardance of radionuclides. (authors)

  16. Studies of Tc oxidation states in humic acid solutions

    International Nuclear Information System (INIS)

    Wang Bo; Liu Dejun; Yao Jun

    2011-01-01

    The oxidation state of Tc is an important aspect of the speciation in groundwater which contained organic substances due to it control the precipitation, complexation, sorption and colloid formation behavior of the Tc under HWL geological disposal conditions. In present work, the oxidation states of Tc were investigated using the LaCl 3 coagulation method and solution extraction method in aqueous solutions in which the humic acid concentration range is from 0 to 20 mg/L and the Tc (VII) concentration is about 10 -8 mol/L. The radiocounting of 99 Tc was determined using liquid scintillation spectrometry. The humic acid will influence the radiocounting ratio of 99 Tc apparently, however, the quenching effect can be restrained once keep the volume of the cocktail to about twenty times of the sample volume. The LaCl 3 coagulation method was carried out for the investigation of Tc oxidation states in humic acid aqueous systems at about pH 8. The tetraphenylarsonium chloride (TPA)-chloroform extraction method was used also simultaneously to investigation the concentrations of Tc (IV) and Tc (VII) for the availability of the LaCl 3 precipitation method, and the experimental results demonstrate that tetravalent technetium and pertechnetate concentration are well agreement with the LaCl 3 precipitation method. These two experimental results demonstrated that Tc (VII) is very stable in the Tc (VII)-humic acid system during a 350 days experimental period, and the Tc (IV) concentrations are very lower, that is indicate that there didn't oxidizing reactions between the Fluka humic acid and Tc (VII) in aqueous solutions under anaerobic conditions. That means the presence of humic acids even in anaerobic groundwater is disadvantage for the retardance of radionuclides. (authors)

  17. Influence of lysozyme complexation with purified Aldrich humic acid on lysozyme activity

    NARCIS (Netherlands)

    Li, Y.; Tan, W.F.; Wang, M.X.; Liu, F.; Weng, L.P.; Norde, W.; Koopal, L.K.

    2012-01-01

    Humic acid is an important component of dissolved organic matter and in two previous papers it has been shown that purified Aldrich humic acid (PAHA) forms strong complexes with the oppositely charged protein lysozyme (LSZ). The complexation and aggregation of enzymes with humic acids may lead to

  18. Lead binding to soil fulvic and humic acids: NICA-Donnan modeling and XAFS spectroscopy

    NARCIS (Netherlands)

    Xiong, J.; Koopal, L.K.; Tan, W.; Fang, L.; Wang, W.; Zhao, W.; Liu, T.; Zhang, J.; Weng, L.

    2013-01-01

    Binding of lead (Pb) to soil fulvic acid (JGFA), soil humic acids (JGHA, JLHA), and lignite-based humic acid (PAHA) was investigated through binding isotherms and XAFS. Pb binding to humic substances (HS) increased with increasing pH and decreasing ionic strength. The NICA-Donnan model described Pb

  19. Europium (III) and americium (III) stability constants with humic acid

    International Nuclear Information System (INIS)

    Torres, R.A.; Choppin, G.R.

    1984-01-01

    The stability constants for tracer concentrations of Eu(III) and Am(III) complexes with a humic acid extracted from a lake-bottom sediment were measured using a solvent extraction system. The organic extractant was di(2-ethylhexyl)-phosphoric acid in toluene while the humate aqueous phase had a constant ionic strength of 0.1 M (NaClO 4 ). Aqueous humic acid concentrations were monitored by measuring uv-visible absorbances at approx.= 380 nm. The total carboxylate capacity of the humic acid was determined by direct potentiometric titration to be 3.86 +- 0.03 meq/g. The humic acid displayed typical characteristics of a polyelectrolyte - the apparent pKsub(a), as well as the calculated metal ion stability constants increased as the degree of ionization (α) increased. The binding data required a fit of two stability constants, β 1 and β 2 , such that for Eu, log β 1 = 8.86 α + 4.39, log β 2 = 3.55 α + 11.06 while for Am, log β 1 = 10.58 α + 3.84, log β 2 = 5.32 α + 10.42. With hydroxide, carbonate, and humate as competing ligands, the humate complex associated with the β 1 constant is calculated to be the dominant species for the trivalent actinides and lanthanides under conditions present in natural waters. (orig.)

  20. Effects on humic substances on the migration of radionuclides: Complexation of actinides with humic substances in natural aquatic systems. Appendix IV

    International Nuclear Information System (INIS)

    Dierckx, A.; Vancluysen, J.; Maes, A.

    1994-01-01

    In this working period, we focused mainly on a possible influence of competing cations on the Eu 3+ -humic acid interaction. Two scenario's were considered. Firstly, the humic acid is fully occupied by the competing cation. From this type of experiments, it became clear that upon coagulation the ensuing kinetics become very important. Experiments concerning this behaviour are running and will be reported later. Furthermore, it can be concluded that the order of influence of the competing cations on the Eu 3+ -humic acid interaction, follows the order of interaction strength of the competing cation with the humic acid (Na + 3 ) 6 ) 3+ 2+ 2+ 3+ ∼Cu 2+ ∼Al 3+ ). Secondly, a novel method was tested to investigate the influence of competing cation concentrations, not sufficient to fully occupy the humic acid. An 'indifferent' cation (Co(NH 3 ) 6 ) 3+ , was used to coagulate the humic acid in order to hinder its diffusion through the membrane. The results obtained in presence and in absence of (Co(NH 3 ) 6 ) 3+ agree with each other but are too preliminary to publish in this progress report. (orig.)

  1. Determination of the protonation enthalpy of humic acid by calorimetric titration technique

    International Nuclear Information System (INIS)

    Kimuro, Shingo; Kirishima, Akira; Sato, Nobuaki

    2015-01-01

    Graphical abstract: The thermodynamic quantities of protonation of humic acid were determined by the combination of potentiometric titration and calorimetric titration. It was observed that the protonation enthalpy and Gibbs free energy had been affected by pH of solution. As a result, the thermodynamics of the protonation reaction of humic acid is influenced by the polyelectrolyte effect and the heterogeneity. - Highlights: • We applied calorimetric titration technique to the protonation of humic acid. • The thermodynamic quantities of protonation of humic acid were determined. • The protonation enthalpy of humic acid is affected by the heterogeneity. • Gibbs free energy of the protonation is affected by the polyelectrolyte effect. - Abstract: In this study, the calorimetric titration technique was used to determine the protonation enthalpy of two reference humic acids and polyacrylic acid. First, we obtained the apparent protonation constant of two kinds of humic acid purchased from IHSS (International Humic Substances Society) and polyacrylic acid by potentiometric titration. Second, we obtained the protonation enthalpy of them by calorimetric titration. The protonation enthalpy of humic acid was affected by pH and the ionic strength of bulk solution. From the comparison of ΔH between humic acid and polyacrylic acid, it was concluded that the pH dependence of ΔH is attributed to the heterogeneity of humic acid. And ΔH of phenolic hydroxyl group in humic acid is strongly influenced by the electric double layer of humic acid’s surface. This is considered to be a reason of the ionic strength dependence of ΔH. On the other hand, Gibbs free energy of the protonation of humic acid is affected by the electrostatic attraction with the progress of dissociation of functional groups such as carboxyl group and phenolic hydroxyl group. Consequently, the thermodynamics of the protonation of humic acid is affected by the polyelectrolyte effect and the

  2. Attenuation of polychlorinated biphenyl sorption to charcoal by humic acids

    NARCIS (Netherlands)

    Koelmans, A.A.; Meulman, B.; Meijer, T.; Jonker, M.T.O.

    2009-01-01

    Strong sorption to black carbon may limit the environmental risks of organic pollutants, but interactions with cosorbing humic acid (HA) may interfere. We studied the attenuative effect of HA additions on the sorption of polychlorinated biphenyls (PCBs) to a charcoal. "Intrinsic" sorption to

  3. Coagulation of some humic acid solutions by Moringa oleifera Lam ...

    African Journals Online (AJOL)

    10 g/L) were required to clarify humic acid solutions whereas 0.5 g/L were used to remove 90% of initial turbidity of a surface water. ... (coagulation of both surface water and distilled water containing a suspension of mineral particles) deal mainly with the effect of some ... metals, pesticides, etc.) inside the water [11, 12].

  4. Comparison of humic acids production by Trichoderma viride and ...

    African Journals Online (AJOL)

    The performance of each species was compared by examining spore production in oat medium, and the significant medium components and fermentation conditions were identified using Plackett and Burman statistical design. For both Trichoderma species, the results indicate that humic acids production can be enhanced ...

  5. Fractionation of humic acid upon adsorption to goethite

    NARCIS (Netherlands)

    Qin, Xiaopeng; Liu, Fei; Wang, Guangcai; Hou, Hong; Li, Fasheng; Weng, Liping

    2015-01-01

    The fractionation and replacement of humic acid (HA) during its interactions with goethite (or goethite-coated sand) were conducted using batch and column experiments. The weight-average molecular weight (Mw) of HA in solutions was determined by a high performance size exclusion chromatography

  6. Humic acids of vermicompost as an ecological pathway to increase ...

    African Journals Online (AJOL)

    Humic acids of vermicompost as an ecological pathway to increase resistance of rice seedlings to water stress. ... Changes in plant anatomy and morphology before and after stress initiation were employed as biomarkers of plant response. The growth rate over time, water content, dry-mass content, leaf carbohydrates, ...

  7. Attenuation of polychlorinated biphenyl sorption to charcoal by humic acids.

    NARCIS (Netherlands)

    Koelmans, A.A.; Meulman, B.; Meijer, T.; Jonker, M.T.O.

    2009-01-01

    Strong sorption to black carbon may limit the environmental risks of organic pollutants, but interactions with cosorbing humic acid (HA) may interfere. We studied the attenuative effect of HA additions on the sorption of polychlorinated biphenyls (PCBs) to a charcoal. "Intrinsic" sorption to

  8. Determination of carboxyl groups in humic acids by FTIR spectrophotometry

    Czech Academy of Sciences Publication Activity Database

    Novák, František; Machovič, V.; Poledna, J.

    2005-01-01

    Roč. 1, č. 1 (2005), s. 141 ISSN 1336-7242. [Zjazd chemických spoločností /57./. 04.09.2005-08.09.2005, Tatranské Matliare] Institutional research plan: CEZ:AV0Z60660521 Keywords : carboxyl groups * humic acids * FTIR spectrophotometry Subject RIV: EH - Ecology, Behaviour

  9. Influence of vermicompost humic acid on chlorophyll content and ...

    African Journals Online (AJOL)

    Vermicompost humic acids (VHA) promote plants' growth because they have similar effects with auxins. The aim of this research was to evaluate the effect of VHA in some physiological indicators in the micropropagation and acclimatization phase of banana clone Enano Guantanamero. Six concentrations were used (0, 10, ...

  10. Compost effect on soil humic acid: A NMR study.

    Science.gov (United States)

    Adani, Fabrizio; Genevini, Pierluigi; Tambone, Fulvia; Montoneri, Enzo

    2006-11-01

    The humic acid (HA) fraction of a food and vegetable residues compost (CM) was taken as indicator to trace the fate of CM organic matter in four years CM amended soil. (1)H and (13)C NMR spectroscopy were used to investigate the nature of the HA isolates from CM, control soil (S(4)) and amended soil. The result indicated a significant structural difference between CM HA and S(4) HA, and supported the presence of both HA fractions in soil at the end of the amendment trials. However, the nature and content of CM HA in soil did not fully explain the increase of soil cation exchange capacity (CEC) after amendment. All CM humic fractions (i.e., fulvic acid, humic acid and humin) were found to contribute to the change of the soil organic matter composition. It is concluded that although CM HA is a suitable indicator of the survival of compost organic matter in soil during amendment, all three humic fractions should be monitored and analyzed to fully understand changes in the composition and properties of amended soil.

  11. Isolation of humic acid from oxidized lignite and complexation with metal cations

    Directory of Open Access Journals (Sweden)

    Ćatović Benjamin

    2017-01-01

    Full Text Available Lignite is brown coal, which in its composition contains humic acids. Humic acids are produced by coal combustion, which leads to the enrichment of coal humic acids. Lignite, from the opet pit mine Šikulje, lignite ore „Kreka“, Bosnia and Herzegovina, was fragmented and sieved to the appropriate size and used as a base material. The isolation of humic acid was carried out from pre-oxidized and dried lignite after which it was refined. Identification thus obtained humic acids was carried out by FTIR spectroscopy and its characterization of UV analysis which is determined by optical density of isolated humic acid and its complexation with metal cations. Data obtained by FTIR spectroscopic analysis of isolated humic acids show no significant structural and chemical difference in relation to the spectrum obtained for standard humic acids (Sigma Aldrich. UV analysis showed that isolated and standard humic acid have E4/E6 ratio in an appropriate range of 3–5, which indicates the presence of a large number of aliphatic structure. Based on the degree of humification was found that the isolated humic acids belong to the type B standard while humic acids belong to type A. The most important property of the humic substances is the ability to interact with the metal ions forming soluble or insoluble complexes which possess different chemical and biological properties and stability. The nature of the complex between humic acid and metal cation derived from the heterogeneous, polyelectric and polydispersive character humic acids that occurs due to the presence of a large number of functional groups. Complexation of humic acid is carried out with different concentrations of metal nitrate solutions and at different pH values. Different amounts of humic acids were used for the complexation. The amount of the free metal ions was measured with the ICP-OES methode. The data were also statistically analyzed with ANOVA. The results showed that increasing the p

  12. Characterization of aquatic humic substances to DBPs formation in advanced treatment processes for conventionally treated water.

    Science.gov (United States)

    Kim, Hyun-Chul; Yu, Myong-Jin

    2007-05-08

    An advanced water treatment demonstration plant consisted of ozone/granular activated carbon processes was operated to study feasibility of the processes. Natural organic matter (NOM) from raw and process waters at the demonstration plant was isolated into humic and non-humic fractions by physicochemical fractionation method to investigate characteristics of humic fraction (i.e., humic substances, HS) as a predominant haloform reactant. Ozone did not significantly oxidize the carboxylic fraction (from 39.1 to 35.9%), while GAC removed some of the carboxylic fraction (from 35.9 to 29.1%). Formation potential of trihalomethanes (THMs) as compared to haloacetic acids formation potential (HAAFP) was highly influenced by HS. Higher yields of THMs resulted from chlorination of HS with a higher phenolic content and phenolic fraction in the HS gradually decreased from 60.5% to 15.8% through the water treatment. The structural and functional changes of HS were identified by elemental, Fourier-transform infrared (FT-IR) and proton nuclear magnetic resonance ((1)H NMR) analyses, and these results were mutually consistent. The functional distribution data obtained by using A-21 resin could be used to support the interpretation of data obtained from the spectroscopic analyses. Decreases in ratio of UV absorbance at 253 nm and 203 nm (A(253)/A(203)) and DBPFPs/DOC showed consistent trends, therefore, A(253)/A(203) ratio may be a good indicator for the disinfection by-product formation potentials (DBPFPs).

  13. Temperature Induced Aggregation and Clouding in Humic Acid Solutions

    Directory of Open Access Journals (Sweden)

    Leah Shaffer

    2015-01-01

    Full Text Available Humic acids in aqueous solution demonstrate inverse temperature-solubility relationships when solution conditions are manipulated to reduce coulombic repulsion among the humic polyanions. These effects were followed by dynamic light scattering (DLS measurements of the resulting aggregates, as well as the addition of a polarity sensitive fluorescent probe (pyrene. The humic solutions could be primed for temperature induced clouding by carefully lowering the pH to a point where hydration effects became dominant. The exact value of the cloud point (CP was a function of both pH and humate concentration. The CPs mostly lay in the range 50–90°C, but DLS showed that temperature induced aggregation proceeded from approximately 30°C onward. Similar effects could be achieved by adding multivalent cations at concentrations below those which cause spontaneous precipitation. The declouding of clouded humate solutions could be affected by lowering the temperature combined with mechanical agitation to disentangle the humic polymers.

  14. Reduced humic acid nanosheets and its uses as nanofiller

    Science.gov (United States)

    Duraia, El-shazly M.; Henderson, B.; Beall, Gary W.

    2015-10-01

    Leonardite is highly oxidized form of lignite coal and contains a number of carboxyl groups around the edges of a graphene-like core. A novel approach has been developed to synthesize graphene oxide-like nanosheets in large scale utilizing leonardite as a starting material. Humic acid extracted from leonardite has been reduced by performing a high pressure catalytic hydrogenation. The reaction was carried out inside a high pressure stirred reactor at 150 °C and 750 psi (~5.2×106 Pa). Morphology of the as-synthesized samples showed porous platy particles and EDAX analysis indicates the carbon and oxygen atomic ratios as 96:4-97:3%. The as-synthesized material has been used as nanofiller in polyurethane. The reduced humic acid-polyurethane nanocomposite showed over 250% increase of Young's modulus. This new approach provides a low cost and scalable source for graphene oxide-like nanosheets in nanocomposite applications.

  15. Calculation of molecular weights of humic substances from colligative data: Application to aquatic humus and its molecular size fractions

    Science.gov (United States)

    Reuter, J. H.; Perdue, E. M.

    1981-11-01

    A rigorous mathematical expression for the dependence of colligative properties on acid dissociation of water soluble humic substances is presented. New data for number average molecular weights of a river derived humic material and its gel permeation Chromatographic fractions are compared with M¯n values obtained by a reevaluation of previously published experimental observations on soil and water fulvic acids. The results reveal a remarkable similarity of fulvic acids from widely different sources with respect to number-average molecular weight.

  16. Humic acids quality of Cambisols developed on gneiss and amphibolite

    Czech Academy of Sciences Publication Activity Database

    Pospíšilová, Ľ.; Žigová, Anna; Šťastný, Martin; Liptaj, T.

    2012-01-01

    Roč. 9, č. 4 (2012), s. 503-510 ISSN 1214-9705 R&D Projects: GA ČR GA526/08/0434 Institutional support: RVO:67985831 Keywords : Cambisols * parent material * arable soil, * grassland soil * X-ray diffraction * humic acids * SRATR FTIR and 13C NMR spectroscopy Subject RIV: DF - Soil Science Impact factor: 0.530, year: 2011 http://www.irsm.cas.cz/materialy/acta_content/2012_04/8.Pospisilova.pdf

  17. Novel humic acid-bonded magnetite nanoparticles for protein immobilization

    Energy Technology Data Exchange (ETDEWEB)

    Bayrakci, Mevlut, E-mail: mevlutbayrakci@gmail.com [Ulukisla Vocational School, Nigde University, 51100 Ulukisla, Nigde (Turkey); Gezici, Orhan [Department of Chemistry, Nigde University, 51100 Nigde (Turkey); Bas, Salih Zeki; Ozmen, Mustafa; Maltas, Esra [Department of Chemistry, Selcuk University, 42031 Konya (Turkey)

    2014-09-01

    The present paper is the first report that introduces (i) a useful methodology for chemical immobilization of humic acid (HA) to aminopropyltriethoxysilane-functionalized magnetite iron oxide nanoparticles (APS-MNPs) and (ii) human serum albumin (HSA) binding to the obtained material (HA-APS-MNPs). The newly prepared magnetite nanoparticle was characterized by using Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and elemental analysis. Results indicated that surface modification of the bare magnetite nanoparticles (MNPs) with aminopropyltriethoxysilane (APS) and HA was successfully performed. The protein binding studies that were evaluated in batch mode exhibited that HA-APS-MNPs could be efficiently used as a substrate for the binding of HSA from aqueous solutions. Usually, recovery values higher than 90% were found to be feasible by HA-APS-MNPs, while that value was around 2% and 70% in the cases of MNPs and APS-MNPs, respectively. Hence, the capacity of MNPs was found to be significantly improved by immobilization of HA. Furthermore, thermal degradation of HA-APS-MNPs and HSA bonded HA-APS-MNPs was evaluated in terms of the Horowitz–Metzger equation in order to determine kinetic parameters for thermal decomposition. Activation energies calculated for HA-APS-MNPs (20.74 kJ mol{sup −1}) and HSA bonded HA-APS-MNPs (33.42 kJ mol{sup −1}) implied chemical immobilization of HA to APS-MNPs, and tight interactions between HA and HA-APS-MNPs. - Highlights: • A new magnetite nanoparticle based humic acid was prepared for the first time. • Protein binding studies of magnetite nanoparticle based humic acid were performed. • Kinetic parameters of protein and/or humic acid bonded nanoparticles were evaluated.

  18. Characterization of typical aquatic humic substances in areas of sugarcane cultivation in Brazil using tetramethylammonium hydroxide thermochemolysis

    Energy Technology Data Exchange (ETDEWEB)

    Tadini, A.M.; Constantino, I.C. [Departamento de Química e Ciências Ambientais, Instituto de Biociências, Letras e Ciências Exatas, Universidade Estadual Paulista “Júlio de Mesquita Filho”, R. Cristóvão Colombo 2265, 15054-000 São José do Rio Preto, SP (Brazil); Nuzzo, A.; Spaccini, R.; Piccolo, A. [Dipartimento Scienze del Suolo, della Pianta, e dell' Ambiente, Università di Napoli Federico II, Via Università 100, 80055 Portici (Italy); Moreira, A.B. [Departamento de Química e Ciências Ambientais, Instituto de Biociências, Letras e Ciências Exatas, Universidade Estadual Paulista “Júlio de Mesquita Filho”, R. Cristóvão Colombo 2265, 15054-000 São José do Rio Preto, SP (Brazil); and others

    2015-06-15

    Aquatic humic substances (AHSs) differ from one environment to another depending on land use and occupation. In addition, the effects of planting sugarcane on AHSs are not well known. Thus, the aim of this study was to characterize AHSs extracted from a river in a typical region of sugarcane cultivation during dry and rainy seasons. The main characteristics of the AHSs were obtained using Fourier transformation infrared (FTIR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy and off-line pyrolysis coupled with gas chromatography and mass spectrometry (off-line tetramethylammonium hydroxide (TMAH)-GC–MS-thermochemolysis). The FTIR and NMR results were used to infer that no distinctions occurred between the sampling periods. The samples were composed of aromatic groups that were potentially associated with the presence of residual vegetable materials (lignin). The results of the off-line TMAH-GC–MS-thermochemolysis indicated that the structures of the AHSs had uniform compositions that were rich in fatty acid methyl esters (FAMEs), polysaccharide derivatives, aliphatic biopolymers derived from plants, long hydrocarbon chains, branched alkyl groups and methylene carbons. Thus, the results showed that the AHSs obtained from the sugarcane cultivation area during the crop period mainly consisted of resistant aliphatic hydrocarbons, which are derivatives of lignin and FAMEs in compounds rich in humic acid. Therefore, we concluded that sugarcane cultivation produces changes in AHSs because greater amounts of lignin derivatives were observed during the dry season, corresponding to sugarcane cultivation. - Highlights: • AHSs differ from one environment to another depending on land use and occupation. • AHSs extracted from a river in a typical region of sugarcane cultivation. • AHSs from the sugarcane area are influenced by the soil use and occupation. • AHSs contain lignin derivatives, fatty acid methyl esters and others. • Lignin was observed with

  19. Sorption of tebuconazole onto selected soil minerals and humic acids.

    Science.gov (United States)

    Cadková, Eva; Komárek, Michael; Kaliszová, Regina; Koudelková, Věra; Dvořák, Jiří; Vaněk, Aleš

    2012-01-01

    The aim of the present study was to investigate tebuconazole sorption on common soil minerals (birnessite, ferrihydrite, goethite, calcite and illite) and humic acids (representing soil organic matter). Tebuconazole was used (i) in the commercial form Horizon 250 EW and (ii) as an analytical grade pure chemical. In the experiment with the commercially available tebuconazole, a significant pH-dependent sorption onto the oxides was observed (decreasing sorption with increasing pH). The highest sorption was found for ferrihydrite due to its high specific surface area, followed by humic acids, birnessite, goethite and illite. No detectable sorption was found for calcite. The sorption of analytical grade tebuconazole on all selected minerals was significantly lower compared to the commercial product. The sorption was the highest for humic acids, followed by ferrihydrite and illite and almost negligible for goethite and birnessite without any pH dependence. Again, no sorption was observed for calcite. The differences in sorption of the commercially available and analytical grade tebuconazole can be attributed to the additives (e.g., solvents) present in the commercial product. This work proved the importance of soil mineralogy and composition of the commercially available pesticides on the behavior of tebuconazole in soils.

  20. Study on the Effects of Humic Acid on Germination of Four Wheat Cultivars (Triticun aestivum L.)

    OpenAIRE

    S Sabzevari; H Khazaie; M Kafi

    2011-01-01

    Abstract Humic acid is an organic acid without environmental destructive effects that is applied for increasing germination rate and wheat establishment. In order to evaluate effects of different levels of humic acid on germination of four wheat cultivars; an experiment was conducted in 2008 at Research Laboratory of Faculty of Agriculture, Ferdowsi University of Mashhad. A randomized completely block design with four replications used with factorial combination of humic acid concentrati...

  1. Acceleration on the Growth of Rubber Planting Materials by Using Foliar Application of Humic Acid

    OpenAIRE

    Cahyo, Andi Nur; Ardika, Risal; Saputra, Jamin; Wijaya, Thomas

    2014-01-01

    The best rubber planting materials are needed to build the best rubber plantation. Humic acids could be used to improve the growth of rubber planting materials. Humic acid plays a role as a hormone-like substance. This research was aimed to determine the optimal concentration of foliar application of humic acid in order to enhance the growth of rubber tree planting materials. This research was arranged in a completely randomized block design with five treatments and four replicates. The treat...

  2. Association constants of modified humic acids with biocides of the triazole series: Cyproconazole and tebuconazole

    Science.gov (United States)

    Mal'Tseva, E. V.; Yudina, N. V.; Chaikovskaya, O. N.; Nechaev, L. V.

    2011-09-01

    The interaction of humic acids with biocides of triazoles in dependence on the concentration of components in solutions was investigated by spectrofluorimetry. The complex behavior of intermolecular interactions between biocides and humic acids, including donor-acceptor and hydrophobic bonds, was established. The effect of conditions of mechanochemical modification of humic acids and pH on the efficiency of interaction with biocides is shown.

  3. Laccase-mediated transformation of triclosan in aqueous solution with metal cations and humic acid.

    Science.gov (United States)

    Sun, Kai; Kang, Fuxing; Waigi, Michael Gatheru; Gao, Yanzheng; Huang, Qingguo

    2017-01-01

    Triclosan (TCS) is a broad-spectrum antimicrobial agent that is found extensively in natural aquatic environments. Enzyme-catalyzed oxidative coupling reactions (ECOCRs) can be used to remove TCS in aqueous solution, but there is limited information available to indicate how metal cations (MCs) and natural organic matter (NOM) influence the environmental fate of TCS during laccase-mediated ECOCRs. In this study, we demonstrated that the naturally occurring laccase from Pleurotus ostreatus was effective in removing TCS during ECOCRs, and the oligomerization of TCS was identified as the dominant reaction pathway by high-resolution mass spectrometry (HRMS). The growth inhibition studies of green algae (Chlamydomonas reinhardtii and Scenedesmus obliquus) proved that laccase-mediated ECOCRs could effectively reduce the toxicity of TCS. The presence of dissolved MCs (Mn 2+ , Al 3+ , Ca 2+ , Cu 2+ , and Fe 2+ ions) influenced the removal and transformation of TCS via different mechanisms. Additionally, the transformation of TCS in systems with NOM derived from humic acid (HA) was hindered, and the apparent pseudo first-order kinetics rate constants (k) for TCS decreased as the HA concentration increased, which likely corresponded to the combined effect of both noncovalent (sorption) and covalent binding between TCS and humic molecules. Our results provide a novel insight into the fate and transformation of TCS by laccase-mediated ECOCRs in natural aquatic environments in the presence of MCs and NOM. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. The measurement of the molecular weight of humic acid by ultracentrifugation

    International Nuclear Information System (INIS)

    Gardner, M.P.

    1989-07-01

    This report is concerned with the application of ultracentrifuge methods to the determination of humic acid molecular weights. The work has been undertaken as part of the Co-Co club intercomparison exercise on humic acid characterisation. Knowledge of the molecular weight distribution of humic acid will be an important parameter in assessing the likely physical and chemical behaviour under the near-field environment. Molecular weights of a sample of purified Aldrich humic acid have been obtained by sedimentation velocity and sedimentation equilibrium studies using an analytical ultracentrifuge. The results have shown the material to be polydisperse with a weight average molecular weight in the region 2700 to 4000. (author)

  5. Humic acid provenance influence to the adsorption capacity in uranium and thorium removal

    Science.gov (United States)

    Prasetyo, E.

    2018-01-01

    It is common knowledge that humic acid is organic compound without certain chemical composition since it is derived from different organic materials. Further this raises question whether the different humic acid sample used could lead to different adsorbent properties e.g. adsorption capacity. To address the problem, this paper is aimed to clarify the relation between the provenances of humic acid and synthesized adsorbent properties especially adsorption capacities by quantitative and qualitative functional groups determination including discussion on their effect to the metal ion adsorption mechanism using three humic acid samples. Two commercial samples were derived from recent compost while the other extracted from tertiary carbonaceous mudstone strata.

  6. Reduction of Pu(V) and Np(V) by leonardite humic acids and their quinonoid-enriched derivatives

    International Nuclear Information System (INIS)

    Shcherbina, N.S.; Kalmykov, St.N.; Perminova, I.V.; Kovalenko, A.N.

    2005-01-01

    Full text of publication follows: Humic substances (HS) are natural poly-electrolytes ubiquitous in aquatic environment responsible for complexation of metal ions. The presence of phenolic and quinonoid moieties in the structure of HS provide for their ability to take part in redox interactions. Capability of HS to reduce plutonium from higher oxidation states (Pu(V) and Pu(VI)) to tetravalent state was reported in several studies. However, the disparate results were reported for Np(V). The contradicting results on the redox behavior of HS could originate from the structural differences of the humic materials tested, in particular, from varying content of the redox-active quinonoid moieties. To test this hypothesis, the goal of this research was to evaluate reducing performance of leonardite humic acids and of their quinonoid-enriched derivatives with respect to Pu(V) and Np(V). The quinonoid-enriched humic derivatives were obtained using the reaction of formaldehyde co-poly-condensation between parent humic material - leonardite humic acid - and model dihydroxybenzenes - hydroquinone, catechol and 1,4-benzoquinone. The humic material: quinonoid monomer ration of 1 g per 250 mg was used. The reduction of Np(V) was studied at micro- and macro-concentration level: 10 -7 M and 10 -4 M, respectively. In case of Pu(V) the concentration was about 10 -10 M. The HS concentrations varied from 1 to 100 ppm, while ionic strength was zero. All experiments were conducted in anaerobic conditions and in the darkness. The kinetics of Pu(V) reduction was studied using solvent extraction (TTA in toluene); to monitor Np(V) reduction two independent techniques were used: solvent extraction and VIS-NIR spectrophotometry. The latter allows measuring absorbance of NpO 2 + and Np-humate complexes at 981.3 and 987.4 nm, respectively. Fast reduction of Pu(V) by the parent humic material was observed and the reduction rate increased with a decrease in pH. In case of Np(V), there was no

  7. Phenanthrene sorption to sequentially extracted soil humic acids and humins.

    Science.gov (United States)

    Kang, Seunghun; Xing, Baoshan

    2005-01-01

    Humic substances strongly influence the environmental fate of hydrophobic organic chemicals in soils and sediments. In this study, the sorption of phenanthrene by humic acids (HAs) and humins was examined. HAs were obtained from progressively extracting a soil, eight times with 0.1 M Na4P207 and two times with 0.1 M NaOH solution, and then the residue was separated into two humin fractions by their organic carbon contents. The chemical and structural heterogeneity of the HAs and humins were characterized by elemental analysis, ultraviolet-visible spectroscopy, diffuse reflectance infrared Fourier transform spectroscopy, and solid-state 13C NMR. There were significant chemical and structural differences among the HA fractions and humins; the later extracted HAs had relatively high aliphatic carbons content. All sorption data were fitted to a Freundlich equation, S = K(F)C(N), where S and C are the sorbed and solution-phase concentrations, respectively, and K(F) and N are constants. All of the phenanthrene sorptions were nonlinear, and the nonlinearity decreased with further extractions from 0.90 (first extracted HA) to 0.96 (ninth HA) and was the lowest (0.88) for the higher organic carbon content humin. Phenanthrene sorption coefficient by HAs significantly increased with progressive extractions, being the highest for the humins. For HAs isotherms, a positive trend was observed between the sorption coefficient and the aliphaticity, but a negative relation was shown between the nonlinearity and the aliphaticity and between the sorption capacity and polarity of HAs. Phenanthrene sorption was greatly affected by chemical structure and composition of humic substances, even from a same soil. In addition, polarity of humic substances seems to mainly regulate the magnitude of phenanthrene sorption rather than structure.

  8. Characterization of the interactions between endocrine disruptors and aquatic humic substances from tropical rivers

    Energy Technology Data Exchange (ETDEWEB)

    Botero, Wander G. [Universidade Federal de Alagoas (UFAL), Arapiraca, AL (Brazil); Oliveira, Luciana C. de [Universidade Federal de Sao Carlos (UFSCar), Sorocaba, SP (Brazil); Cunha, Bruno B.; Oliveira, Lilian K. de; Goveia, Danielle; Fraceto, Leonardo F.; Rosa, Andre Henrique, E-mail: ahrosa@sorocaba.unesp.b [UNESP, Sorocaba, SP (Brazil). Dept. de Engenharia do Meio Ambiente; Rocha, Julio Cesar [UNESP, Araraquara, SP (Brazil). Inst. de Quimica. Dept. de Quimica Analitica

    2011-07-01

    Interactions between two endocrine disruptors (ED) and aquatic humic substances (AHS) from tropical rivers were studied using an ultrafiltration system equipped with a 1 kDa cut-off cellulose membrane to separate free ED from the fraction bound in the AHS. Quantification of 17{alpha}-ethynylestradiol and bisphenol A was performed using gas chromatography-mass spectrometry (GC-MS). The times required for establishment of equilibrium between the AHS and the ED were ca. 30 min, and complexation capacities for 17{alpha}-ethynylestradiol and bisphenol A were 18.53 and 2.07 mg g{sup -1} TOC, respectively. The greater interaction of AHS with 17{alpha}-ethynylestradiol, compared to bisphenol A, was due to the presence of hydrogen in the structure of 17{alpha}-ethynylestradiol, which could interact with ionized oxygenated groups of the AHS. The results indicate that AHS can strongly influence the transport and reactivity of endocrine disruptors in aquatic systems. (author)

  9. Amide and Ester-Functionalized Humic Acid for Fuel Combustion Enhancement

    Science.gov (United States)

    Riggs, Mark

    Humic acid is a class of naturally occurring molecules composed of large sheet-like regions of cyclic aromatic hydrocarbon networks with surface and edge functional groups including phenols, carboxylic acids, and epoxides. These naturally occurring molecules are found in brown coal deposits near lignite formations. Humic acid has gained attention from the scientific community as a precursor for graphene. Graphene is a 2-dimensional honeycomb structure of fully unsaturated carbon atoms that has exceptional material properties and inherent aromaticity. Graphene's incredible properties are matched by the difficulty associated with reproducibly manufacturing it on a large scale. This issue has limited the use of graphene for commercial applications. The polar functional groups of humic acid contribute to the hydrophilic nature of the molecule, limiting its miscibility in any alkyl-based solvent. Surfactants containing long alkyl chains can affect the miscibility of the molecule in an organic solvent. Surfactants are often difficult to remove from the system. It is theorized that alkylation of the functional sites of humic acid can affect the hydrophilic nature of the molecule, and effectively enable its dispersion into organic solvents without simultaneous incorporation of surfactants. This dissertation investigated the amidation and esterification of humic acid molecules extracted from leonardite. The resulting change in the modified humic acid dispersibility in organic solvents and its potential usage as a fuel additive were evaluated. Butyl, hexyl, octyl, and decyl amide-modified and ester-modified humic acids were synthesized. These products were characterized to confirm successful chemical reaction through thermogravimetric analysis, Fourier-transform infrared spectroscopy, and scanning electron microscopy. The decyl-modified humic acids remained suspended in kerosene mixtures for longer than 1 week. Other organo-humic acids showed varying degrees of flocculation

  10. HPLC studies of aquatic humic compounds and complexes from the Drigg Research Site, Cumbria

    International Nuclear Information System (INIS)

    Smith, B.

    1991-01-01

    This report describes an investigation into the applicability of high performance liquid chromatographic techniques for the separation of the complex mixtures of organic acids commonly found in groundwaters. This work has shown that reverse phase ion-pair chromatography using a large pore stationary phase can be successfully applied to humic material in both natural and concentrated groundwater from the Drigg Research Site. The methodology separates the organic species into a number of well resolved components the majority of which have a molecular weight of greater than 500 Dalton. Separations obtained have been qualitatively and quantitatively analysed using a Diode array spectrophotometer. The components in excess of 500 Dalton show UV absorption spectra similar to humic and fulvic acids where as the component with a molecular weight of less than 500 Dalton shows a sharp UV absorption cutoff at 230 nm. It was noted that this component was not removed by passage through DEAEA cellulose. Reverse phase HPLC was also investigated, and results were found to be consistent with a separation based on an ion-repulsion/size exclusion mechanism. It was concluded that any separation based on this mechanism is likely to suffer from poor inter run reproducibility and must therefore be discounted as a suitable method. Similarly, ion-suppression reverse phase was shown to be equally impracticable, requiring a mobile phase pH of less than 2 to obtain separation (this low pH renders a silica based stationary phase unstable). (author)

  11. Optimized Extraction Method To Remove Humic Acid Interferences from Soil Samples Prior to Microbial Proteome Measurements.

    Science.gov (United States)

    Qian, Chen; Hettich, Robert L

    2017-07-07

    The microbial composition and their activities in soil environments play a critical role in organic matter transformation and nutrient cycling. Liquid chromatography coupled to high-performance mass spectrometry provides a powerful approach to characterize soil microbiomes; however, the limited microbial biomass and the presence of abundant interferences in soil samples present major challenges to proteome extraction and subsequent MS measurement. To this end, we have designed an experimental method to improve microbial proteome measurement by removing the soil-borne humic substances coextraction from soils. Our approach employs an in situ detergent-based microbial lysis/TCA precipitation coupled to an additional cleanup step involving acidified precipitation and filtering at the peptide level to remove most of the humic acid interferences prior to proteolytic peptide measurement. The novelty of this approach is an integration to exploit two different characteristics of humic acids: (1) Humic acids are insoluble in acidic solution but should not be removed at the protein level, as undesirable protein removal may also occur. Rather it is better to leave the humics acids in the samples until the peptide level, at which point the significant differential solubility of humic acids versus peptides at low pH can be exploited very efficiently. (2) Most of the humic acids have larger molecule weights than the peptides. Therefore, filtering a pH 2 to 3 peptide solution with a 10 kDa filter will remove most of the humic acids. This method is easily interfaced with normal proteolytic processing approaches and provides a reliable and straightforward protein extraction method that efficiently removes soil-borne humic substances without inducing proteome sample loss or biasing protein identification in mass spectrometry. In general, this humic acid removal step is universal and can be adopted by any workflow to effectively remove humic acids to avoid them negatively competing

  12. Evaluation of the Efficiency of Electron Beam Irradiation for Removal of Humic Acid from Aqueous Solutions

    Directory of Open Access Journals (Sweden)

    Mohammad hasan Ehrampoosh

    2017-05-01

    Full Text Available Background: Humic acids (HAs have adverse effects on the environment; therefore, they should be removed from the water and wastewater. The aim of this study was to evaluate the efficiency of the electron beam irradiation for removal of humic acid from aqueous solutions. Methods: Humic acid was purchased from Sigma-Aldrich Company. After preparation of stock solution in alkaline condition, different concentrations of humic acid (10, 25 and 50 mg were prepared. Study has done at pH= 8 and in different dose rates of 1, 3, 6, 9 and 15 kGy. Then initial absorption of samples was measured at 254 nm using UV-Visible spectrophotometer before and after the irradiation. Excel and SPSS Ver. 18 were used for analyzing the data and drawing graphs. Results: The results of this study showed that by increasing adsorbed dose from 1 to 15 kGy, the efficiency of HA removal increased and by increasing humic acid concentration from 10 to 50 mg/L, the removal efficiency of humic acid decreased. The results of the kinetic study showed that irradiation of humic acid followed pseudo second-order reaction. Conclusion: It can be concluded that electron beam irradiation can be a useful technology for the treatment of environmental samples contaminated by humic acid.

  13. Effects of Humic Acid on the Germination Traits of Pumpkin Seeds under Cadmium Stress

    Directory of Open Access Journals (Sweden)

    Maasoumeh ASADI

    2013-12-01

    Full Text Available The study tackled the effect of humic acid and cadmium concentrations on the pumpkin seed germination characteristics throughout were studied. Treatments were cadmium concentrations on three levels: 0, 100 and 200 ppm and humic acid concentration of 0, 100, 200, 300 and 400 mg lit-1. Results showed that interaction of humic acid and cadmium was not significant on germination traits, but there was a significant effect on seedling growth indexes. Radicle and plumule length increased by 86 and 192% in comparison with control, of the mixture of 200 ppm cadmium and 300 mg lit-1 of humic acid. Cadmium had stimulatory effect on radicle and cotyledon dry weight and the highest values obtained with 200 ppm in mixture with 200 mg lit-1 of humic acid. Also, maximum plumule dry weight was recorded in 200 ppm cadmium and 300 mg lit-1 of humic acid. The highest of indexes were observed of 200 ppm cadmium and 400 mg lit-1 humic acid. In conclusion, the humic acid had detoxifying effect on cadmium stress in the culture and responded antagonistically against cadmium, but it seems that these concentrations of cadmium are low for the pumpkin seed and can be increased in order to reach the toxicity level.

  14. Influence of humic acid on the trichloroethene degradation by Dehalococcoides-containing consortium

    International Nuclear Information System (INIS)

    Hu Miao; Zhang Ying; Wang Zhigang; Jiang Zhao; Li Juan

    2011-01-01

    By taking an anaerobic Dehalococcoides-containing consortium (designated UC-1) as the research object, the influence of humic acid on the degradation of TCE by UC-1 was examined. The results indicated that (i) TCE was more rapidly degraded in the presence of humic acid compared with the control and the TCE removal efficiencies increased with the increase of concentrations of humic acid; and (ii) at the end of experiments, in the presence of humic acid, much more ethene was produced compared with the control, whereas less VC was accumulated in the medium. Presumably, humic acid improves the activity of organisms in dechlorinating populations resulting in more ethene accumulated in the medium, and (iii) the degradation of TCE stimulated by humic acid by UC-1 might be a biotic process or an abiotic process. Thus, humic acid could influence the degradation of TCE by UC-1 directly via enhancing electron transfer between UC-1 and TCE. This work is a preliminary step for accelerating the degradation of TCE in the groundwater environment using a kind of natural organic matter - humic acid.

  15. Influence of Soil Humic and Fulvic Acid on the Activity and Stability of Lysozyme and Urease

    NARCIS (Netherlands)

    Li, Yan; Tan, WenFeng; Koopal, Luuk K.; Wang, MingXia; Liu, Fan; Norde, Willem

    2013-01-01

    Humic substances (HS), including humic acids (HA) and fulvic acids (FA), are important components of soil systems. HS form strong complexes with oppositely charged proteins, which will lead to changes in the enzyme activity. The effect of soil HS on the activity and stability of two enzymes was

  16. Influence of soil humic and fulvic acid on the activity and stability of lysozyme and urease

    NARCIS (Netherlands)

    Li, Y.; Tan, W.; Koopal, L.K.; Wang, M.; Liu, Fan; Norde, W.

    2013-01-01

    Humic substances (HS), including humic acids (HA) and fulvic acids (FA), are important components of soil systems. HS form strong complexes with oppositely charged proteins, which will lead to changes in the enzyme activity. The effect of soil HS on the activity and stability of two enzymes was

  17. The effect of various chemical treatments on the pyrolytic pattern of peat humic acid

    Energy Technology Data Exchange (ETDEWEB)

    Almendros, G.; Martin, F.; Gonzalez-Vila, F.J.; Delrio, J.C. (CSIC, Madrid (Spain). Centro de Ciencies Medioambientales)

    1993-06-01

    The present study describes the pyrolytic patterns of a series of humic preparations obtained from a peat humic acid subjected to chemical modifications, such as methylation, oximation, sulphonation, nitration, amidation, ammonia fixation, acetylation, acid and alkaline hydrolysis, hydrogen peroxide treatment, etc. Some diagnostic pyrolysis compounds were found which can be useful in studying N speciation in humic substances. In addition, the noticeable differences in the distribution patterns of the alkeyl series released upon pyrolysis were interpreted in terms of the changes introduced in the structural arrangement of the humic macromolecules.

  18. Humic and hymatomelanic acids interaction with lanthanide ions

    Science.gov (United States)

    Jerzykiewicz, Maria

    2012-10-01

    The interactions of lanthanide ions, REE(III), with semiquinone radicals naturally occurring in humic (HA) and hymatomelanic (HY) acids of different origin were studied mainly by EPR spectroscopy. Quantitative EPR analysis proved that only the semiquinone free radical concentration in both, HA and HY, was affected by interaction with some of the lanthanide ions, whereas the EPR g parameters of the formed radical-REE(III) complexes remained unchanged. The radical concentration was practically unaffected by the REE(III) ions with 4f1-4f6 electron configurations and in some degree increased by REE(III) ions with 4f8-4f14 configuration. The lanthanide playing an exceptional role was Gd(III) (4f7), which diminished strongly the free radicals concentration. The quenching ability of Gd(III) was stronger towards the radicals provided by HA than by HY, what was assigned to higher content in HA of both, oxygen-containing functional groups and conjugated aromatic rings, leading to more efficient Gd(III)-radical interaction. The semiquinone free radicals of HA and HY originated from the compost were more reactive than those from peat, as the humic acids from mature compost with less bulk density have more accessible functional groups.

  19. Phenanthrene sorption to soil humic acid and different humin fractions.

    Science.gov (United States)

    Wen, Bei; Zhang, Jing-Jing; Zhang, Shu-Zhen; Shan, Xiao-Quan; Khan, Shahamat U; Xing, Baoshan

    2007-05-01

    This study was undertaken to provide an insight into the effect of heterogeneous soil organic matter (SOM) on the sorption of phenanthrene. Humic acid (HA) and humin were extracted from a peat soil. Humin was further fractionated into bound-humic acid (BHA), lipid, and insoluble residue (IR) fractions. Heterogeneous natures of these fractions were characterized by elemental analysis, ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy, and solid-state 13C NMR. Aliphaticity of the fractions followed the order lipid >BHA > HA > IR, while the polarity order was IR > BHA> HA > lipid. Sorption of phenanthrene on these fractions fitted the Freundlich equation, suggesting that phenanthrene sorption isotherms of lipid were almost linear (N = 0.993), while those of HA, BHA, and IR were nonlinear, with N values ranging from 0.723 to 0.910. The N values followed the order lipid > HA > BHA > IR and were significantly correlated inversely with their polarities (p Organic carbon-normalized sorption coefficients (K(FOC)) were independent of aliphatic or aromatic contents of the SOM fractions. The results suggested that SOM, especially for the humin fractions, was highly heterogeneous in terms of elemental composition, structure, and polarity. Such heterogeneity was considered to be responsible forthe nonlinear sorption of phenanthrene.

  20. [Forming mechanism of humic acid-kaolin complexes and the adsorption of trichloroethylene].

    Science.gov (United States)

    Zhu, Xiao-jing; He, Jiang-tao; Su, Si-hui

    2015-01-01

    The interaction between soil organic components and mineral components was explored in this study. Humic acid and kaolin were used for the preparation of organic-mineral complexes with different contents of organic matter, for experimental study of the adsorption of trichloroethylene. The results showed that the adsorption of trichlorethylene fitted the Freundlich isotherm model. The existence of interaction between humic acid and kaolin was indicated by the significant difference between the actual value and the theoretically overlaid value of the adsorption capacity. With various characterizations, such as FTIR and surface area & pore analysis, the mechanism of interaction between humic acid and kaolin was suggested as follows. When their contents were low, humic acid molecules firstly loaded on the surface binding sites of kaolin. Then with the content increased, as O/M( organic-mineral mass ratio) was 0.02-0.04, some surface pores of kaolin were filled by part of the molecules. After reaching a relatively stable stage, as O/M was 0.04-0.08, humic molecules continued to load on the surface of kaolin and formed the first humic molecule-layer. With humic acid content continued increasing, as O/M was 0.08-0.10, more humic molecules attached to kaolin surface through the interaction with the first layer of molecules and then formed the second layer. O/M was 0.10-0.16 as the whole second layer stage, meanwhile the first layer was compressed. Then when O/M was 0.16-0.4, there were still some humic loadings onto the second layer as the third layer, and further compressed the inner humic acid layers. Besides, some humic acid molecules or aggregates might go on attaching to form as further outer layer.

  1. Flow column experiments on the migration characteristics of dissolved humic acids in sediments of different grain size

    International Nuclear Information System (INIS)

    Klotz, D.

    2001-01-01

    Humic acids dissolved in water can be retained in sediments by sorption and filtration. The resulting retardation depends on the properties of the humic acids (composition, concentration) and sediments (specific surface, pore geometry). The deposition/solution of humic acids affects the pore geometry and thus the hydraulic characteristics of the sediments [de

  2. Molecular Features of Humic Acids and Fulvic Acids from Contrasting Environments

    NARCIS (Netherlands)

    Schellekens, Judith; Buurman, Peter; Kalbitz, Karsten; Zomeren, van Andre; Vidal-Torrado, Pablo; Cerli, Chiara; Comans, Rob N.J.

    2017-01-01

    Insight in the molecular structure of humic acid (HA) and fulvic acid (FA) can contribute to identify relationships between their molecular properties, and further our quantitative abilities to model important organic matter functions such as metal complexation and association with mineral

  3. Characterization of the coal derived humic acids from Mukah, Sarawak as soil conditioner

    Directory of Open Access Journals (Sweden)

    Fong Sim Siong

    2006-01-01

    Full Text Available In Malaysia, abundant coal resources were found in Sarawak and Sabah. The utilization of coal resources, to date, is emphasized on the energy productions. The non-energy utilization as soil conditioner is unexplored. Therefore, this study attempted to characterize the coal humic acids extracted from Mukah coal and to evaluate its properties as soil conditioner. The coal humic acids from the regenerated sample were also assessed. The results revealed that different extractants and concentrations influenced the properties of humic acids. The extraction with KOH at 0.5 mol L-1 produced humic acids with low ash content and high acidic functional groups, which are substantial as soil conditioner. However, the yield was low. Regeneration of coal sample with 10% nitric acids improved the yield to an average of 83.45%. The acidic functional groups of nitrohumic acids were improved with the ash content remained at a low level.

  4. Оptimization of humic acids extraction from coal of Oy-karagay field

    Directory of Open Access Journals (Sweden)

    Zhaksyntay Kairbekov

    2012-12-01

    Full Text Available Optimum conditions of extraction of humic acids from brown coal of a domestic Oy-Karagay field using the  method of experiment planning were defined: extraction temperature – 80 оC; duration of experiment – 45 minutes; concentration of alkali – 1,0 %; ratio of coal and alkali solution equal 1:25. The experiment realized in these conditions is coordinated with sampled data. The  composition of the humic acids extracted after alkaline processing of brown coal have been  investigated by  IR-spectroscopy. IR spectrum of humic acids contains a band due to the active acidic groups.

  5. The effect of different replications of humic acid fertilization on yield ...

    African Journals Online (AJOL)

    Jane

    2011-06-22

    Jun 22, 2011 ... humic substances. Some researchers found that humic acid increased the yields in some plants. Studies have shown that this substance has caused yield increase of. 22 to 23% (Adani et al., 1998) and 36.3% (Togun and. Akanbi, 2003) in tomato, 32.5 to 42.5% in maize (Tan and Binger, 1986), 10 to 30% ...

  6. Organic carbon and humic acids in sediments of the Arabian Sea and factors governing their distribution

    Digital Repository Service at National Institute of Oceanography (India)

    Sardessai, S.

    Organic carbon and humic acids in the sediments of the Arabian Sea show distinct regional variations to the south and north of 15~'N latitude. Significant variations are also observed from the shelf to the slope regions. Organic carbon and humic...

  7. ACCELERATION ON THE GROWTH OF RUBBER PLANTING MATERIALS BY USING FOLIAR APPLICATION OF HUMIC ACID

    Directory of Open Access Journals (Sweden)

    Andi Nur Cahyo

    2014-06-01

    Full Text Available The best rubber planting materials are needed to build the best rubber plantation. Humic acids could be used to improve the growth of rubber planting materials. Humic acid plays a role as a hormone-like substance. This research was aimed to determine the optimal concentration of foliar application of humic acid in order to enhance the growth of rubber tree planting materials. This research was arranged in a completely randomized block design with five treatments and four replicates. The treatments were the concentrations of humic acids, i. e. 0; 250; 500; 750; and 1,000 ppm. Observations were made on rubber tree diameter, plant height, shoot and root biomass, and nutrient content of leaves and the stem. The results showed that foliar application of 1,000 ppm of humic acids could enhance the growth of rubber tree planting materials. Foliar application of 500 – 1,000 ppm of humic acids could increase K content of the stem. The effects of foliar application of humic acids were more apparent in the root part than in the shoot part.

  8. Determination of humic acid in alkali leaching solution of uranium by spectophotrometry-COD method

    International Nuclear Information System (INIS)

    Feng Yu; An Wei; Chen Shusen

    2014-01-01

    It is one of the main causes of extraction emulsification or resin toxicosis during alkali leaching process in uranium metallurgy which organic matters including humic acid exist in lixiviums. In order to study the effect of humic acid in uranium metallurgy, a method for determination of content of humic acid in aqueous solution need to be established. Spectrophotometry is a simple and convenient method in humic acid analysis. However, accuracy of spectrophotometry can be reduced greatly because of interference of uranium and other elements in the humic acid solutions. Although chemical oxygen demand (COD) method is a common analysis way of organic matters in aqueous solutions, the concentration of humic acid cannot be directly measured. In this paper, COD method is related with spectrophotometry to avoid the interference of uranium and ensure the accurate analysis of humic acid. The results showed that the detection limit of the method was 1.78 mg/L and the recovery rate was 101.2%. (authors)

  9. Effect of Humic Acid on some Agronomic Characters of some Varieties of Alfalfa (Medicago sativa L.

    Directory of Open Access Journals (Sweden)

    Ali Tadayyon

    2016-10-01

    Full Text Available To evaluate the effect of humic acid on some cultural characters of some alfalfa varieties, a field experiment was conducted as factorial split plot based on RCBD design with three replications in 2014. In this experiment, 5 varieties of alfalfa (Yazdi, Hamedani, Baghdadi, Bami and Ranger and three levels of humic acid (5 and 10 lha-1 and without humic acid, as control were considered as the first factor and harvest time was as the second factor. Result indicated that except plant height, other characteristics such as dry weight yield, dry weight per plant, root and shoot dry weight per plant, number of leaves and stem diameter were affected by triple interaction effect of harvest time×variety×humic acid. Plant height was affected by double interaction effect of variety×humic acid and also harvest time×variety. Yazdi and Bami had the highest and Ranger had the least values of traits under study in two cuttings, respectively. Also in the between of humic acid treatments, 10 lha-1 treatment produced highest traits measured as compared to control and 5 lha-1 treatment. Bami, Ranger and Yazdi varieties with 10 lha-1of humic acid in two cuttings produced the highest dry weight yield (3.64, 3.55 and 3.26 t.ha-1 respectively in this experiment.

  10. Effects of humic acid on adsorption of actinide elements on rocks and others

    Energy Technology Data Exchange (ETDEWEB)

    Ohashi, Masakazu; Sato, Seichi; Ohashi, Hiroshi [Hokkaido Univ., Sapporo (Japan). Faculty of Engineering; Sakamoto, Yoshiaki; Nagao, Seiya; Onuki, Toshihiko; Senoo, Muneaki

    1996-01-01

    Since the transfer rates of radionuclides are reduced by their adsorption to rocks and soils, it is essential to elucidate the adsorption process for safety assessment of their geological disposal. In this study, adsorption of Np(V) to goethite, one of the widely distributed minerals was investigated as functions of pH and humic acid concentration. The surface charge density of goethite was determined and the zero charge point was 6.2 for synthesized and 6.4 for natural goethite. Since the point for humic acid was 4.5, adsorption sites for humic acid were reduced as the increase of negative charge density above pH6, resulting in a decrease in its adsorption rate. Np(V) adsorption to goethite was raised by the presence of humic acid in the range of 0-10ppm because the surface charge on the rock was shifted to negative by the adsorption of humic acid, resulting in easy adsorption of NpO{sub 2}{sup +}, which is stable in the condition below pH 9.5. On the other hand, humic acid adsorption was saturated at a concentration higher than 50 ppm, but its content in the solution would increase. Thus, it was thought that Np(V)-humic acid complex becomes more stable, resulting in the decrease in Np(V) adsorption rate. (M.N.)

  11. Humic acids: Their detergent qualities and potential uses in pollution remediation

    Directory of Open Access Journals (Sweden)

    von Wandruszka Ray

    2000-04-01

    Full Text Available Humic acids are amphiphilic species whose behavior in aqueous solution suggests that they form pseudomicelles–aggregates akin to the micelles familiar from synthetic surfactant chemistry. It is thought that humic pseudomicelles can be formed by both intramolecular coiling and intermolecular association, depending on the molecular weight, structural characteristics, and polydispersity of the humic acid in question. The process does not feature a critical micelle concentration. Experimental evidence indicates that metal ions enhance the detergent character of dissolved humic acid by facilitating the coiling and folding of the polymer chains. A recently conceived alternative model suggests that humic acids consist of relatively small subunits that associate through weak molecular interactions. This view appears to run counter to certain experimental observations, but deserves careful attention. The strong association between metal ions and solid humic acid makes it possible to use an inexpensive commercial grade for the decontamination of polluted water. A continuous elution process through a column packed with humic acid allows for the removal of both heavy metals and organic xenobiotics from aqueous solution.

  12. Mitigation of Humic Acid Inhibition in Anaerobic Digestion of Cellulose by Addition of Various Salts

    Directory of Open Access Journals (Sweden)

    Samet Azman

    2015-03-01

    Full Text Available Humic compounds are inhibitory to the anaerobic hydrolysis of cellulosic biomass. In this study, the impact of salt addition to mitigate the inhibitory effects of humic compounds was investigated. The experiment was conducted using batch tests to monitor the anaerobic hydrolysis of cellulose in the presence of humic acid. Sodium, potassium, calcium, magnesium and iron salts were tested separately for their efficiency to mitigate humic acid inhibition. All experiments were done under mesophilic conditions (30 °C and at pH 7. Methane production was monitored online, using the Automatic Methane Potential Test System. Methane production, soluble chemical oxygen demand and volatile fatty acid content of the samples were measured to calculate the hydrolysis efficiencies. Addition of magnesium, calcium and iron salts clearly mitigated the inhibitory effects of humic acid and hydrolysis efficiencies reached up to 75%, 65% and 72%, respectively, which were similar to control experiments. Conversely, potassium and sodium salts addition did not mitigate the inhibition and hydrolysis efficiencies were found to be less than 40%. Mitigation of humic acid inhibition via salt addition was also validated by inductively coupled plasma atomic emission spectroscopy analyses, which showed the binding capacity of different cations to humic acid.

  13. TiO(2)-assisted photocatalytic degradation of humic acids: effect of copper ions.

    Science.gov (United States)

    Uyguner, C S; Bekbolet, M

    2010-01-01

    The present study investigated the removal efficiency of aqueous humic acid solutions by TiO(2) photocatalytic degradation in the presence of Cu(II) species. The pseudo-first-order kinetics revealed rate constants as 9.87 x 10(-3), 7.19 x 10(-3), 3.81 x 10(-3) min(-1) for Color(436), UV(254) and TOC, respectively. Comparatively, lower rate constants were attained with respect to photocatalytic degradation of humic acid. Considering the source-dependent diverse chemical and spectral characteristics of NOM, a particular interaction would be expected for humic acid with Cu(II) species (0.1 mg L(-1)). The presence of copper ions significantly altered the photocatalytic degradation kinetics of humic acids in relation to the concentration effects of humic acid as expressed by spectroscopic parameters and TOC. Batch equilibrium adsorption experiments revealed a distinct Langmuirian-type adsorptive behavior of humic acid onto TiO(2) both in terms of UV(254) and Color(436) and a C-type adsorption isotherm was attained for TOC. K(F) values displayed an inconsistent effect of Cu(II) species, while adsorption intensity factor 1/ncopper ions and humic molecular size fractions, spectroscopic techniques were also employed for the assessment of the adsorption as well as photocatalytic degradation efficiencies.

  14. Peat humic acids and their complex forming properties as influenced by peat humification

    Science.gov (United States)

    Dudare, D.; Klavins, M.

    2012-04-01

    To study paleoenvironmental changes of importance is understanding of processes of organic matter diagenesis, especially changes of refractory part of natural organic substances - humic substances. Studies of the living organic matter humification process are also essential for understanding of the carbon biogeochemical cycle. The aim of this study was to analyze peat organic matter diagenesis: changes of properties of humic acids, relations between the humification process, properties of peat, peat humic acids, their ability to interact with metal ions, as well ability to accumulate metals. The analysis were carried out on samples of humic substances preparatively extracted from three ombrotrophic bog peat profiles to identify the links between peat age, decomposition and humification degree, botanical composition and properties of peat humic acids elemental (C, H, N, O), functional (-COOH, -OH) composition, structural characteristics - UV, fluorescence, FTIR. The found variability of peat properties is less significant than differences in the properties of peat-forming living matter, thus revealing the dominant impact of humification process on the properties of peat. Correspondingly, composition of peat humic acids is little affected by differences in the properties of precursor living organic material, and such indicators as decomposition degree, humification degree, humic acid elemental ratio and concentrations of acidic functional groups are the best descriptors of changes in organic matter during the process of organic matter diagenesis and humification. Peat ability to accumulate major and trace elements depends on the character of element supply, potency of metal ions to bind functionalities in the peat, with an emphasis on the structure of peat humic acid, pH reaction, oxygen presence, presence of complexing compounds, inorganic ions and many other factors. Major and trace element presence in peat is of importance as an indicator of peat genesis and

  15. Effects of heating on composition, degree of darkness, and stacking nanostructure of soil humic acids

    Energy Technology Data Exchange (ETDEWEB)

    Katsumi, Naoya, E-mail: n-katsu@ishikawa-pu.ac.jp; Yonebayashi, Koyo; Okazaki, Masanori

    2016-01-15

    Wildfires and prescribed burning can affect both the quality and the quantity of organic matter in soils. In this study, we investigated qualitative and quantitative changes of soil humic substances in two different soils (an Entisol from a paddy field and an Inceptisol from a cedar forest) under several controlled heating conditions. Soil samples were heated in a muffle furnace at 200, 250, or 300 °C for 1, 3, 5, or 12 h. The humic acid and fulvic acid contents of the soil samples prior to and after heating were determined. The degree of darkness, elemental composition, carbon and nitrogen stable isotope ratios, {sup 13}C nuclear magnetic resonance spectra, and X-ray diffraction patterns of humic acids extracted from the soils before and after heating were measured. The proportion of humic acids in total carbon decreased with increasing heating time at high temperature (300 °C), but increased with increasing heating time at ≤ 250 °C. The degree of darkness of the humic acids increased with increasing heating time and temperature. During darkening, the H/C atomic ratios, the proportion of aromatic C, and the carbon and nitrogen stable isotope ratios increased, whereas the proportions of alkyl C and O-alkyl C decreased. X-ray diffraction analysis verified that a stacking nanostructure developed by heating. Changes in the chemical structure of the humic acids from the heated soils depended on the type of soil. The major structural components of the humic acids from the heated Entisol were aromatic C and carboxylic C, whereas aliphatic C, aromatic C, and carboxylic C structural components were found in the humic acids from the heated Inceptisol. These results suggest that the heat-induced changes in the chemical structure of the humic acids depended on the source plant. - Highlights: • Darkness of humic acids increased with increasing heating time and temperature. • Aromatic carbon content increased during darkening. • Carbon and nitrogen stable isotope

  16. Stabilization of polynuclear plutonium(IV) species by humic acid

    Science.gov (United States)

    Marsac, Rémi; Banik, Nidhu Lal; Marquardt, Christian Michael; Kratz, Jens Volker

    2014-04-01

    Although the formation of tetravalent plutonium (Pu(IV)) polymers with natural organic matter was previously observed by spectroscopy, there is no quantitative evidence of such reaction in batch experiments. In the present study, Pu(IV) interaction with humic acid (HA) was investigated at pH 1.8, 2.5 and 3, as a function of HA concentration and for Pu total concentration equal to 6 × 10-8 M. The finally measured Pu(IV) concentrations ([Pu(IV)]eq) are below Pu(IV) solubility limit. Pu(IV)-HA interaction can be explained by the complexation of Pu(IV) monomers by HA up to [Pu(IV)]eq ∼ 10-8 M. However, the slope of the log-log Pu(IV)-HA binding isotherm changes from ∼0.7 to ∼3.5 for higher [Pu(IV)]eq than ∼10-8 M and at any pH. This result suggests the stabilization of hydrolyzed polymeric Pu(IV) species by HA, with a 4:1 Pu:HA stoichiometry. This confirms, for the first time, previous observations made by spectroscopy in concentrated systems. The humic-ion binding model, Model VII, was introduced into the geochemical speciation program PHREEQC and was used to simulate Pu(IV) monomers binding to HA. The simulations are consistent with other tetravalent actinides-HA binding data from literature. The stabilization of a Pu tetramer (Pu4(OH)88+) by HA was proposed to illustrate the present experimental results for [Pu(IV)]eq > 10-8 M. Predictive simulations of Pu(IV) apparent solubility due to HA show that the chosen Pu(IV)-polymer has no impact for pH > 4. However, the comparison between these predictions and recent spectroscopic results suggest that more hydrolyzed polymeric Pu(IV) species can be stabilized by HA at pH > 4. Polymeric Pu(IV)-HA species might significantly enhance Pu(IV) apparent solubility due to humics, which support a colloid-facilitated transport of this low solubility element.

  17. Effects of peat fires on the characteristics of humic acid extracted from peat soil in Central Kalimantan, Indonesia.

    Science.gov (United States)

    Yustiawati; Kihara, Yusuke; Sazawa, Kazuto; Kuramitz, Hideki; Kurasaki, Masaaki; Saito, Takeshi; Hosokawa, Toshiyuki; Syawal, M Suhaemi; Wulandari, Linda; Hendri I; Tanaka, Shunitz

    2015-02-01

    When peat forest fires happen, it leads to burn soil and also humic acids as a dominant organic matter contained in peat soil as well as the forest. The structure and properties of humic acids vary depending on their origin and environment, therefore the transformation of humic acid is also diverse. The impacts of the peat fires on peat soil from Central Kalimantan, Indonesia were investigated through the characterization of humic acids, extracted from soil in burnt and unburnt sites. The characterization of humic acids was performed by elemental composition, functional groups, molecular weight by HPSEC, pyrolysate compounds by pyrolysis-GC/MS, fluorescence spectrum by 3DEEM spectrofluorometer, and thermogravimetry. The elemental composition of each humic substance indicated that the value of H/C and O/C of humic acids from burnt sites were lower than that from unburnt sites. The molecular weight of humic acids from burnt sites was also lower than that from unburnt sites. Pyrolysate compounds of humic acids from unburnt sites differed from those of humic acids from burnt soil. The heating experiment showed that burning process caused the significant change in the properties of humic acids such as increasing the aromaticity and decreasing the molecular weight.

  18. The influence of aquatic humic substances characteristics on the coagulation efficiency using ferric chloride; Influencia das caracteristicas das substancias humicas aquaticas na eficiencia da coagulacao com o cloreto ferrico

    Energy Technology Data Exchange (ETDEWEB)

    Sloboda, Eliane; Vieira, Eny Maria [Universidade de Sao Paulo (USP), Sao Carlos, SP (Brazil). Inst. de Quimica], e-mail: elisloboda@hotmail.com; Dantas, Angela Di Bernardo; Bernardo, Luiz Di [Universidade de Sao Paulo (USP), Sao Carlos, SP (Brazil). Escola de Engenharia. Dept. de Hidraulica e Saneamento

    2009-07-01

    The aim of this study was to verify the influence of the apparent molecular size of aquatic humic substances on the effectiveness of coagulation with ferric chloride. Coagulation-filtration tests using jar test and bench-scale sand filters were carried out on samples of water with true color of approximately 100 Hazen units, prepared with aquatic humic substances of different molecular sizes (F{sub 1}: < 0.45 {mu}m, F{sub 2}: 100 kDa - 0.45 {mu}m, F{sub 3}: 30 - 100 kDa and F{sub 4}{sup '} : < 30 kDa). For the water samples with lower apparent molecular size fractions, greater dosages of coagulant was needed to remove the color around 5.0 Hanzen units, mainly because these water samples contain higher concentrations of fulvic acids, which exhibited a larger number of negatively-charged groups. (author)

  19. Influence of vermicompost humic acid on chlorophyll content and ...

    African Journals Online (AJOL)

    S

    2016-11-23

    Nov 23, 2016 ... cattle used was fed mainly with grasses, and the manure was processed with African red worm. This vermicompost was used for the humic substances extraction according to International humic substances society (2008) with NaOH (0.1 mol L-1) in a proportion of 1:10 (mg of vermicompost: mL dissolution) ...

  20. A study of the chemical composition of peat humic acids by adsorption liquid chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Platonov, V.V.; Proskuryakov, V.A.; Surasinkha, S.; Platonova, M.V.; Taran, N.A. [Lev Tolstoi State Pedagogical University, Tula (Russian Federation)

    1998-12-01

    The chemical composition of peat humic acids was studied in detail by IR and UV spectroscopy, elemental, emission spectral X-ray fluorescence, and structural-group analyses, cryoscopy, and capillary gas chromatography.

  1. Photodegradation of bisphenol A in simulated lake water containing algae, humic acid and ferric ions

    International Nuclear Information System (INIS)

    Peng Zhang'e; Wu Feng; Deng Nansheng

    2006-01-01

    The photodegradation of bisphenol A (BPA), a suspected endocrine disruptor (ED), in simulated lake water containing algae, humic acid and Fe 3+ ions was investigated. Algae, humic acid and Fe 3+ ions enhanced the photodegradation of BPA. Photodegradation efficiency of BPA was 36% after 4 h irradiation in the presence of 6.5 x 10 9 cells L -1 raw Chlorella vulgaris, 4 mg L -1 humic acid and 20 μmol L -1 Fe 3+ . The photodegradation efficiency of BPA was higher in the presence of algae treated with ultrasonic than that without ultrasonic. The photodegradation efficiency of BPA in the water only containing algae treated with ultrasonic was 37% after 4 h irradiation. The algae treated with heating can also enhance the photodegradation of BPA. This work helps environmental scientists to understand the photochemical behavior of BPA in lake water. - Algae, humic acid and ferric ions can induce the photodegradation of bisphenol A in an aqueous environment

  2. Assessing the Effect of Humic Acids on Germinating a Native American Plant

    National Research Council Canada - National Science Library

    Nicola, Senesi

    2004-01-01

    ... (HAs) in Idaho soils on seed germination and seedling early-growth of slickspot peppergrass, and their possible relations to the compositional, structural and functional characteristics of humic acids...

  3. Evaluation of NaOH leaching techniques to extract humic acids from palaeosols

    Energy Technology Data Exchange (ETDEWEB)

    Head, M.J. E-mail: john_head@uow.edu.au; Zhou, W.J

    2000-10-01

    It can be shown quite conclusively that the often used technique (AAA) of leaching palaeosol samples with hot or boiling dilute HCl solution, followed by treatment with up to 2% NaOH solution and a further treatment with dilute HCl solution may not remove all of the so-called humic acids from palaeosol samples. In fact, in many cases it does not remove any of the humic acids, only carbohydrates, amino acids and other organic compounds. This can be shown by examination of the visible spectrum (400-700 nm) of the 'humic acid' extract in alkaline solution. Hence, many of the reported {sup 14}C results from the 'humin' fraction of palaeosols are actually from the humic acid fraction which is tightly bound to the clay component of the palaeosol. The NaOH leach also has the potential to introduce carboxylic acid groups from atmospheric CO{sub 2} into phenol groups. A reevaluation of humic acid extracts of palaeosols collected from the Loess Plateau in China has been made, with analyses comparing the properties of the various organic extracts. Also, an extraction technique based on recommendations from the International Humic Substances Society, incorporating removal of impurities by chromatography plus a decarboxylation step is proposed.

  4. Humic acids enhance the microbially mediated release of sedimentary ferrous iron.

    Science.gov (United States)

    Chang, Chun-Han; Wei, Chia-Cheng; Lin, Li-Hung; Tu, Tzu-Hsuan; Liao, Vivian Hsiu-Chuan

    2016-03-01

    Iron (Fe) is an essential element for many organisms, but high concentrations of iron can be toxic. The complex relation between iron, arsenic (As), bacteria, and organic matter in sediments and groundwater is still an issue of environmental concern. The present study addresses the effects of humic acids and microorganisms on the mobilization of iron in sediments from an arsenic-affected area, and the microbial diversity was analyzed. The results showed that the addition of 50, 100, and 500 mg/L humic acids enhanced ferrous iron (Fe(II)) release in a time-dependent and dose-dependent fashion under anaerobic conditions. A significant increase in the soluble Fe(II) concentrations occurred in the aqueous phases of the samples during the first 2 weeks, and aqueous Fe(II) reached its maximum concentrations after 8 weeks at the following Fe(II) concentrations: 28.95 ± 1.16 mg/L (original non-sterilized sediments), 32.50 ± 0.71 mg/L (50 mg/L humic acid-amended, non-sterilized sediments), 37.50 ± 1.85 mg/L (100 mg/L humic acid-amended, non-sterilized sediments), and 39.00 ± 0.43 mg/L (500 mg/L humic acid-amended, non-sterilized sediments). These results suggest that humic acids can further enhance the microbially mediated release of sedimentary iron under anaerobic conditions. By contrast, very insignificant amounts of iron release were observed from sterilized sediments (the abiotic controls), even with the supplementation of humic acids under anaerobic incubation. In addition, the As(III) release was increased from 50 ± 10 μg/L (original non-sterilized sediments) to 110 ± 45 μg/L (100 mg/L humic acid-amended, non-sterilized sediments) after 8 weeks of anaerobic incubation. Furthermore, a microbial community analysis indicated that the predominant class was changed from Alphaproteobacteria to Deltaproteobacteria, and clearly increased populations of Geobacter sp., Paludibacter sp., and Methylophaga sp. were found after adding humic acids

  5. Proton resonance spectra of humic acids from the solum of a podzol

    International Nuclear Information System (INIS)

    Lentz, H.; Luedemann, H.-D.; Ziechmann, W.

    1977-01-01

    The proton resonance spectra at 100 MHz are reported for humic acids extracted from A and B horizons of an Erica Podzol at pH = 4.5, 7, and 14. The spectra were taken of 5% w/w solutions in 0.1 N sodium deuterooxide in heavy water. Differences between humic acids from the A and B horizons can be quantitatively measured by proton resonance spectra

  6. Effects of humic and fulvic acids on release of fixed potassium

    International Nuclear Information System (INIS)

    Tan, K.H.

    1978-01-01

    Release of potassium fixed by expanding silicate clays is considered of practical importance in soil fertility. Humic and fulvic acids are expected to play a definite role in liberating this fixed K, because of their chelating power, but not much is known in this respect. This investigation was conducted to study release of fixed K by montmorillonite and illite, using humic and fulvic acids isolated from the surface horizon of a Cecil soil (Typic Hapludult, Red Yellow Podzolic soil) as extractants. (Auth.)

  7. Identification of bound alcohols in soil humic acids by gas chromatography-mass spectrometry

    OpenAIRE

    Berthier , Gersende; Dou , Sen; Peakman , Torren; Lichtfouse , Eric

    2000-01-01

    International audience; Humic acids are complex, partly macromolecular, yellow-brownish substances occurring in soils, waters and sediments. In order to shed some light on their molecular structure, crop humic acids were cleaved by alkaline hydrolysis (KOH). The products were fractionated by thin layer chromatography to give mono-alcohols which were analysed as acetate derivatives by gas chromatography coupled to mass spectrometry. Linear alcohols, sterols, stanols and plant-derived triterpen...

  8. Interactions of mercury with different molecular weight fractions of humic substances in aquatic systems.

    Digital Repository Service at National Institute of Oceanography (India)

    Chakraborty, P.; Yao, K.M.; Chennuri, K.; Vudamala, K.; Babu, P.V.R.

    Interactions of mercury (Hg) with different molecular weight fractions of humic substances (HS) play an important role in controlling distribution, diffusion, speciation, and bioavailability of Hg in natural systems. This study suggests that Hg...

  9. Coating of AFM probes with aquatic humic and non-humic NOM to study their adhesion properties

    KAUST Repository

    Aubry, Cyril

    2013-06-01

    Atomic force microscopy (AFM) was used to study interaction forces between four Natural Organic Matter (NOM) samples of different physicochemical characteristics and origins and mica surface at a wide range of ionic strength. All NOM samples were strongly adsorbed on positively charged iron oxide-coated silica colloidal probe. Cross-sectioning by focused ion beam milling technique and elemental mapping by energy-filtered transmission electron microscopy indicated coating completeness of the NOM-coated colloidal probes. AFM-generated force-distance curves were analyzed to elucidate the nature and mechanisms of these interacting forces. Electrostatics and steric interactions were important contributors to repulsive forces during approach, although the latter became more influential with increasing ionic strength. Retracting force profiles showed a NOM adhesion behavior on mica consistent with its physicochemical characteristics. Humic-like substances, referred as the least hydrophilic NOM fraction, i.e., so called hydrophobic NOM, poorly adsorbed on hydrophilic mica due to their high content of ionized carboxyl groups and aromatic/hydrophobic character. However, adhesion force increased with increasing ionic strength, suggesting double layer compression. Conversely, polysaccharide-like substances showed high adhesion to mica. Hydrogen-bonding between hydroxyl groups on polysaccharide-like substances and highly electronegative elements on mica was suggested as the main adsorption mechanism, where the adhesion force decreased with increasing ionic strength. Results from this investigation indicated that all NOM samples retained their characteristics after the coating procedure. The experimental approach followed in this study can potentially be extended to investigate interactions between NOM and clean or fouled membranes as a function of NOM physicochemical characteristics and solution chemistry. © 2013 Elsevier Ltd.

  10. The effect of humic acids on biodegradation of polycyclic aromatic hydrocarbons depends on the exposure regime

    International Nuclear Information System (INIS)

    Tejeda-Agredano, Maria-Carmen; Mayer, Philipp; Ortega-Calvo, Jose-Julio

    2014-01-01

    Binding of polycyclic aromatic hydrocarbons (PAHs) to dissolved organic matter (DOM) can reduce the freely dissolved concentration, increase apparent solubility or enhance diffusive mass transfer. To study the effects of DOM on biodegradation, we used phenanthrene and pyrene as model PAHs, soil humic acids as model DOM and a soil Mycobacterium strain as a representative degrader organism. Humic acids enhanced the biodegradation of pyrene when present as solid crystals but not when initially dissolved or provided by partitioning from a polymer. Synchronous fluorescence spectrophotometry, scintillation counting and a microscale diffusion technique were applied in order to determine the kinetics of dissolution and diffusive mass transfer of pyrene. We suggest that humic acids can enhance or inhibit biodegradation as a result of the balance of two opposite effects, namely, solubilization of the chemicals on the one hand and inhibition of cell adhesion to the pollutant source on the other. Highlights: • Humic acids can enhance the biodegradation of PAHs. • The enhancement depends on how the bacteria are exposed to PAHs. • Humic acids stimulate if PAHs are provided by dissolution form crystals. • An inhibition occurs if PAHs are provided by partitioning from a silicone. • The balance between enhanced dissolution and decreased adhesion is the cause. -- Humic acids cause opposite effects on biodegradation of PAHs depending on the exposure regime

  11. Influence of seasonality on the interaction of mercury with aquatic humic substances extracted from the Middle Negro River Basin (Amazon)

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Luciana C. de, E-mail: lcamargo@ufscar.br [Federal University of Sao Carlos (UFSCar), Sorocaba, SP (Brazil); Botero, Wander G. [Federal University of Alagoas (UFAL), Arapiraca, AL (Brazil); Santos, Felipe A. [Institute of Biosciences, Sao Paulo State University (UNESP), Botucatu, SP (Brazil); Sargentini Junior, Ezio [National Amazon Research Institute (INPA), Manaus, AM (Brazil); Rocha, Julio C.; Santos, Ademir dos [Institute of Chemistry of Araraquara, Sao Paulo State University (UNESP), Araraquara, SP (Brazil)

    2012-09-15

    High mercury concentrations in different environmental matrices in the Amazon have been attributed to mining activities. However, high concentrations of mercury are also present in the soil and water in places like in the middle of the Negro River Basin, which is far away from any anthropogenic emission sources. The Amazon region is characterized by two different regional seasons, with well-defined flood and low water periods. The objective of this work was to investigate the seasonal influences of the interaction between mercury and aquatic humic substances (AHS), which are the main agents of the natural organic complexation capacity. The results of the multivariate statistical analysis of the data showed that the humic substances had different structural characteristics, depending on each season. The ability of humic substances to form complexes with Hg(II) is not directly related to their carbon content, but to the nature and availability of the functional groups present in its structure. The functional groups are carboxylic and aromatic directly related to the higher complexation capacity of AHS by mercury ions. (author)

  12. Influence of seasonality on the interaction of mercury with aquatic humic substances extracted from the Middle Negro River Basin (Amazon)

    International Nuclear Information System (INIS)

    Oliveira, Luciana C. de; Botero, Wander G.; Santos, Felipe A.; Sargentini Junior, Ezio; Rocha, Julio C.; Santos, Ademir dos

    2012-01-01

    High mercury concentrations in different environmental matrices in the Amazon have been attributed to mining activities. However, high concentrations of mercury are also present in the soil and water in places like in the middle of the Negro River Basin, which is far away from any anthropogenic emission sources. The Amazon region is characterized by two different regional seasons, with well-defined flood and low water periods. The objective of this work was to investigate the seasonal influences of the interaction between mercury and aquatic humic substances (AHS), which are the main agents of the natural organic complexation capacity. The results of the multivariate statistical analysis of the data showed that the humic substances had different structural characteristics, depending on each season. The ability of humic substances to form complexes with Hg(II) is not directly related to their carbon content, but to the nature and availability of the functional groups present in its structure. The functional groups are carboxylic and aromatic directly related to the higher complexation capacity of AHS by mercury ions. (author)

  13. Effect of humic acid (HA) on sulfonamide sorption by biochars

    International Nuclear Information System (INIS)

    Lian, Fei; Sun, Binbin; Chen, Xi; Zhu, Lingyan; Liu, Zhongqi; Xing, Baoshan

    2015-01-01

    Effect of quantity and fractionation of loaded humic acid (HA) on biochar sorption for sulfonamides was investigated. The HA was applied in two different modes, i.e. pre-coating and co-introduction with sorbate. In pre-coating mode, the polar fractions of HA tended to interact with low-temperature biochars via H-bonding, while the hydrophobic fractions were likely to be adsorbed by high-temperature biochars through hydrophobic and π-π interactions, leading to different composition and structure of the HA adlayers. The influences of HA fractionation on biochar sorption for sulfonamides varied significantly, depending on the nature of interaction between HA fraction and sorbate. Meanwhile, co-introduction of HA with sulfonamides revealed that the effect of HA on sulfonamide sorption was also dependent on HA concentration. These findings suggest that the amount and fractionation of adsorbed HA are tailored by the surface properties of underlying biochars, which differently affect the sorption for organic contaminants. - Highlights: • Effect of quantity and fractionation of coated HA on sorption of sulfonamides by BC was studied. • Fractionation of coated HA is tailored by surface properties of BC. • Roles of HA in BC sorption depend on interaction between HA adlayer and sorbate. • Roles of HA in sulfonamide sorption by BC also depend on HA aqueous concentration. - The quantity and fractionation of adsorbed HA play a major role in sulfonamide sorption by biochars

  14. Interaction of Cocos nucifera cream casein with humic acid suspensions.

    Science.gov (United States)

    Fatombi, J K; Aminou, T; Lartiges, B; Topanou, N; Josse, R G

    2012-01-01

    Two caseins labelled as CaSMG (casein without fats) and CaMG (casein with fats) were extracted from coconut cream. Both caseins were used as coagulants for the aggregation of humic acid (HA) particles in synthetic water at pH = 6 during the jar-test essays. The optimum dosage of CaMG or CaSMG and the residual turbidities of treated water obtained depend on the type of used casein (CaMG or CaSMG) and the concentration of particles in solution. The optimal doses of CaMG and CaSMG are respectively 280 and 180 mg/L for solution S(1) (HA aqueous solution at 15 mg/L), and then 340 and 240 mg/L for solution S(2) (HA aqueous solution at 25 mg/L). The residual turbidities of treated water are respectively 6.88 and 3.85 NTU for solution S(1) and 4.52 and 2.53 NTU for solution S(2). The collected sediment volumes are respectively 1.2 and 1.5 mL for solutions S(1) and S(2). The electrophoretic mobility measurement and transmission electron microscopy images of flocs formed during the flocculation essays suggest that both caseins operate through both mechanisms (charge neutralisation and bridging process mechanism), this last one seems to be predominant. The aggregates formed are the large clusters and result from adsorption of HA particles by the casein molecules.

  15. Photodegradation of chlorpyrifos with humic acid-bound suspended matter.

    Science.gov (United States)

    Amarathunga, A A D; Kazama, F

    2014-09-15

    Land exploitation in several developing countries, including tropical areas, has caused a rapid change of the landscape, from forest to farms. This has led to an increase of pesticide use and concentration of suspended matter in river waters, which may cause soil erosion of these areas. Humic acid (HA), one of the main components in the soil particulate organic matter, has a positive effect on the photodegradation of organic matter in water; however, the efficiency of HA-bound suspended matter (HABSM) for pesticide photodegradation is not known. The aim of this study is to clarify the effect of HABSM on the photodegradation of chlorpyrifos employed in artificial soil particulate covered with HA. Experiments were carried out in liquid HA phase, with/without HABSM phase and HABSM with additional LHA phase under light. The adsorption procedure of the pesticide on HABSM was also studied. Our results reveal that adsorption takes place within a short time period on HABSM and that photodegradation is successfully achieved. The additional LHA+HABSM phase have not demonstrated any significant effect of HA concentration to photodegradation of chlorpyrifos. For instance, when 2.0mg/L chlorpyrifos was used in the experiments, concentration reductions caused by adsorption, photodegradation under suspended matter and HABSM were found to be 19.3, 17.7, and 61.7% respectively. This finding suggests that HABSM can be considered as a potential catalyst for pesticide photodegradation under sunlight. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Kinetics of adsorption of uranium from seawater by humic acids

    International Nuclear Information System (INIS)

    Heitkamp, D.; Wagener, K.

    1990-01-01

    The kinetics of the adsorption of uranium from seawater by humic acids fixed onto a polymer matrix was measured in a fluidized bed as a function of the grain size of the adsorbent and the flow velocity of the seawater. The adsorption rate was found to be governed by the diffusion of the uranium ions through the hydrodynamic surface layer of the adsorbent which is always formed in laminar flows of liquids. The measured rate constants are interpreted in terms of effective diffusion coefficients of 3.6 x 10 -5 cm 2 /s for uranyl ions and 1.8 x 10 -5 cm 2 /s for tricarbonatouranate ions in the surface layer. As a consequence of this kinetic behavior, the geometry of the adsorbent as well as the velocity of the water flow are relevant parameters for the amount of adsorbent needed for a projected extraction rate. This conclusion applies to all adsorption processes where diffusion through the hydrodynamic layer is the rate-determining kinetic step

  17. Phytoremediation of Cu and Zn by vetiver grass in mine soils amended with humic acids.

    Science.gov (United States)

    Vargas, Carmen; Pérez-Esteban, Javier; Escolástico, Consuelo; Masaguer, Alberto; Moliner, Ana

    2016-07-01

    Phytoremediation of contaminated mine soils requires the use of fast-growing, deep-rooted, high-biomass, and metal-tolerant plants with the application of soil amendments that promote metal uptake by plants. A pot experiment was performed to evaluate the combined use of vetiver grass (Chrysopogon zizanioides) and humic acid for phytoremediation of Cu and Zn in mine soils. Vetiver plants were grown in soil samples collected from two mine sites of Spain mixed with a commercial humic acid derived from leonardite at doses of 0, 2, 10, and 20 g kg(-1). Plant metal concentrations and biomass were measured and metal bioavailability in soils was determined by a low molecular weight organic acid extraction. Results showed that humic acid addition decreased organic acid-extractable metals in soil. Although this extraction method is used to estimate bioavailability of metals, it was not a good estimator under these conditions due to competition with the strong chelators in the added humic acid. High doses of humic acid also promoted root growth and increased Cu concentrations in plants due to formation of soluble metal-organic complexes, which enhanced removal of this metal from soil and its accumulation in roots. Although humic acid was not able to improve Zn uptake, it managed to reduce translocation of Zn and Cu to aerial parts of plants. Vetiver resulted unsuitable for phytoextraction, but our study showed that the combined use of this species with humic acid at 10-20 g kg(-1) could be an effective strategy for phytostabilization of mine soils.

  18. Direct solid surface fluorescence spectroscopy of standard chemicals and humic acid in ternary system.

    Science.gov (United States)

    Mounier, S; Nicolodelli, G; Redon, R; Milori, D M B P

    2017-04-15

    The front face fluorescence spectroscopy is often used to quantify chemicals in well-known matrices as it is a rapid and powerful technique, with no sample preparation. However it was not used to investigate extracted organic matter like humic substances. This work aims to fully investigate for the first time front face fluorescence spectroscopy response of a ternary system including boric acid, tryptophan and humic substances, and two binaries system containing quinine sulfate or humic substance in boric acid. Pure chemicals, boric acid, tryptophan, quinine sulfate and humic acid were mixed together in solid pellet at different contents from 0 to 100% in mass. The measurement of excitation emission matrix of fluorescence (3D fluorescence) and laser induced fluorescence were then done in the front face mode. Fluorescence matrices were decomposed using the CP/PARAFAC tools after scattering treatments. Results show that for 3D fluorescence there is no specific component for tryptophan and quinine sulfate, and that humic substances lead to a strong extinction effect for mixture containing quinine sulfate. Laser induced fluorescence gives a very good but non-specific related response for both quinine sulfate and tryptophan. No humic substances fluorescence response was found, but extinction effect is observed as for 3D fluorescence. This effect is stronger for quinine sulfate than for tryptophan. These responses were modeled using a simple absorbance versus emission model. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Humic acid metal cation interaction studied by spectromicroscopy techniques in combination with quantum chemical calculations.

    Science.gov (United States)

    Plaschke, M; Rothe, J; Armbruster, M K; Denecke, M A; Naber, A; Geckeis, H

    2010-03-01

    Humic acids (HA) have a high binding capacity towards traces of toxic metal cations, thus affecting their transport in aquatic systems. Eu(III)-HA aggregates are studied by synchrotron-based scanning transmission X-ray microscopy (STXM) at the carbon K-edge and laser scanning luminescence microscopy (LSLM) at the (5)D(0) --> (7)F(1,2) fluorescence emission lines. Both methods provide the necessary spatial resolution in the sub-micrometre range to resolve characteristic aggregate morphologies: optically dense zones embedded in a matrix of less dense material in STXM images correspond to areas with increased Eu(III) luminescence yield in the LSLM micrographs. In the C 1s-NEXAFS of metal-loaded polyacrylic acid (PAA), used as a HA model compound, a distinct complexation effect is identified. This effect is similar to trends observed in the dense fraction of HA/metal cation aggregates. The strongest complexation effect is observed for the Zr(IV)-HA/PAA system. This effect is confirmed by quantum chemical calculations performed at the ab initio level for model complexes with different metal centres and complex geometries. Without the high spatial resolution of STXM and LSLM and without the combination of molecular modelling with experimental results, the different zones indicating a ;pseudo'-phase separation into strong complexing domains and weaker complexing domains of HA would never have been identified. This type of strategy can be used to study metal interaction with other organic material.

  20. Mechanism of the toxicity induced by natural humic acid on human vascular endothelial cells

    OpenAIRE

    Kihara, Yusuke; Yustiawati; Tanaka, Masato; Gumiri, Sulmin; Ardianor; Hosokawa, Toshiyuki; Tanaka, Shunitz; Saito, Takeshi; Kurasaki, Masaaki

    2012-01-01

    Humic acid (HA), a group of high-molecular weight organic compounds characterized by an ability to bind heavy metals, is normally found in natural water. Although the impairment of vascular endothelial cells in the presence of humic substances has been reported to be involved in some diseases, the mechanisms responsible for this involvement remain unclear. In this study, we examined the cytotoxicity of HA obtained from peatland in Central Kalimantan, Indonesia, to human vascular endothelial c...

  1. Physiological effect of natural humic acid during pregnancy on fetuses and maternal alterations induced by irradiation in rats

    International Nuclear Information System (INIS)

    Abdel gawad, I.I.; Badar, H.M.; Shabon, M.H.

    2005-01-01

    Humic acid is a mixture of macromolecular heterogeneous substances which have high molecular weight. Humic acid is a soil constituent, playing an important role in forming and transferring the nutrients from the soil to the living organism to perform many physiological processes. Thus, the current study was performed to study the chemical characteristics of extracted humic acid (soil constituent in Egypt) and evaluate its physiological effects on irradiated pregnant rats and some maternal biochemical parameter humic acid extract was obtained from the fine fraction of Egyptian soil (undersize 12 mesh sieve). The chemical characters were evaluated by means of IR, ESR, elemental and chemical analyses. It was found to contain all functional groups characterize natural humic acids but it contains high concentration of free radicals (73 x 1018 spin /g). Humic acid was supplemented daily to rats at two separate doses (150 mg and 300 mg/kg) during the interval 1st to 13 th day of gestation. Irradiation (2.5 Gy) was applied one hour post the last dose of humic acid. Experimental investigations were performed on the day 21 of gestation. The results showed that supplementation of rats with humic acid at a dose of 150 mg/kg increased the number of fetuses and placental weight as well as fetal measurement. These morphological effects were paralleled with some biochemical effects in justifying the radioprotective potency of humic acid. Also, the humic acid given at the same dose improved the radiation induced disturbances in serum progesterone, calcium, phosphorus, calcitonin, total proteins and albumin levels whereas administration of humic acid at the high dose (300 mg/kg) induced harmful effect on most of the studied parameters and did not show any protective role against gamma irradiation. It could be concluded that administration of humic acid at the dose of 150 mg/kg during pregnancy of rats exerted a beneficial radioprotective effects on the tested physiological and

  2. Uranium accumulation in Brassica rapa L. and effect of citric acid and humic acids as chelating agents

    International Nuclear Information System (INIS)

    Lopez del R, H.; Perez C, G. A.; Davila R, J. I.; Mireles G, F.; Rodriguez H, G.

    2016-09-01

    Phyto extraction is a technique that makes use of plants for the remediation of soils contaminated with heavy metals. In this study the uranium incorporation in the Brassica rapa L. species was evaluated, in artificially contaminated inert soils with 40 mg U/kg, and the effect of adding of the natural chelating agents citric acid and humic acids in the accumulation of uranium was analyzed. Soil free of organic matter and biologically inert was obtained by controlled calcination s of natural soil. Cultures in the prepared soil consisted of five growth treatments: 1) cultivation without uranium or additives; 2) cultivation in the uranium presence; 3) cultivation with uranium and citric acid (2 g/kg); 4) cultivation with uranium and humic acids (10 g/kg); 5) uranium cultivation and combination of citric and humic acids at the same concentrations. There was no adverse effect on plant growth with the presence of uranium at the given concentration. Regarding the controls, the total biomass in the presence of uranium was slightly higher, while the addition of humic acids significantly stimulated the production of biomass with respect to the citric acid. The combined action of organic acids produced the highest amount of biomass. The efficiency of phyto extraction followed the order Humic acids (301 μg U/g) > Non-assisted (224 μg U/g) >> Citric acid + Humic acids (68 μg U/g) > Citric acid (59 μg U/g). The values of uranium concentration in the total biomass show that the species Brassica rapa L. has the capacity of phyto extraction of uranium in contaminated soils. The addition of humic acids increases the uranium extraction while the addition of citric acid disadvantages it. (Author)

  3. SOIL POLLUTION OF SELECTED PAHS AS A FACTOR AFFECTING THE PROPERTIES OF HUMIC ACIDS

    Directory of Open Access Journals (Sweden)

    Bożena Dębska

    2014-01-01

    Full Text Available It is well-known that the properties of humus soil substances (including humic acids are soil-type-specific. However, one shall consider the fact that properties of organic matter of soil can be modified by farming system (crop rotation, fertilisation as well as other external factors, including pollutants; PAHs. The objective of the paper is to determine the effect of a single-time pollution of soils with high rates of PAHs on the properties of humic acids. The research was performed with the samples of soils representative for the Kujawy and Pomorze Region (Phaeozems, Luvisol, Haplic Arenosols, Fluvisols. Soil samples were polluted with selected PAHs; fluorene, anthracene, pyrene and chrysene at the amount corresponding to 100 mg PAHs · kg-1. Treatments, i.e., soils + PAHs, were incubated for 180 and 360 days at the temperature of 20–25 ºC and at constant moisture of 50 % of field water capacity. Humic acids were extracted from the soil samples prior to and after 180 and 360 days of incubation. The following analyses were performed for separating humic acids: elemental composition, UV-VIS and IR spectrophotometric analyses, susceptibility to oxidation. Results demonstrated that a single introduction of fluorene, anthracene, pyrene and chrysene at very high rates into soils affects the properties of humic acids. There was mostly recorded a decrease in coefficients of absorbance A2/6 and A4/6, an increase in the parameter defining the susceptibility of humic acids to oxidation. There were also noted changes in the pattern of spectra in infrared and the values of the parameter defining the degree of internal oxidation of the humic acids molecules.

  4. Humic and fluvic acids and organic colloidal materials in the environment

    Energy Technology Data Exchange (ETDEWEB)

    Gaffney, J.S.; Marley, N.A. [Argonne National Lab., IL (United States); Clark, S.B. [Univ. of Georgia, Aiken, SC (United States)

    1996-04-01

    Humic substances are ubiquitous in the environment, occurring in all soils, waters, and sediments of the ecosphere. Humic substances arise from the decomposition of plant and animal tissues yet are more stable than their precursors. Their size, molecular weight, elemental composition, structure, and the number and position of functional groups vary, depending on the origin and age of the material. Humic and fulvic substances have been studied extensively for more than 200 years; however, much remains unknown regarding their structure and properties. Humic substances are those organic compounds found in the environment that cannot be classified as any other chemical class of compounds. They are traditionally defined according to their solubilities. Fulvic acids are those organic materials that are soluble in water at all pH values. Humic acids are those materials that are insoluble at acidic pH values (pH < 2) but are soluble at higher pH values. Humin is the fraction of natural organic materials that is insoluble in water at all pH values. These definitions reflect the traditional methods for separating the different fractions from the original mixture. The humic content of soils varies from 0 to almost 10%. In surface waters, the humic content, expressed as dissolved organic carbon (DOC), varies from 0.1 to 50 ppm in dark-water swamps. In ocean waters, the DOC varies from 0.5 to 1.2 ppm at the surface, and the DOC in samples from deep groundwaters varies from 0.1 to 10 ppm. In addition, about 10% of the DOC in surface waters is found in suspended matter, either as organic or organically coated inorganic particulates. Humic materials function as surfactants, with the ability to bind both hydrophobic and hydrophyllic materials, making numic and fluvic materials effective agents in transporting both organic and inorganic contaminants in the environment.

  5. Sorption of tylosin and sulfamethazine on solid humic acid.

    Science.gov (United States)

    Guo, Xuetao; Tu, Bei; Ge, Jianhua; Yang, Chen; Song, Xiaomei; Dang, Zhi

    2016-05-01

    Tylosin (TYL) and sulfamethazine (SMT) are ionizable and polar antimicrobial compounds, which have seeped into the environment in substantial amounts via fertilizing land with manure or sewage. Sorption of TYL and SMT onto humic acid (HA) may affect their environmental fate. In this study, the sorption of TYL and SMT on HA at different conditions (pH, ionic strength) was investigated. All sorption isotherms fitted well to the Henry and Freundlich models and they were highly nonlinear with values of n between 0.5 and 0.8, which suggested that the HA had high heterogeneity. The sorption of TYL and SMT on HA decreased with increasing pH (2.0-7.5), implying that the primary sorption mechanism could be due to cation exchange interactions between TYL(+)/SMT(+) species and the functional groups of HA. Increasing ionic strength resulted in a considerable reduction in the Kd values of TYL and SMT, hinting that interactions between H bonds and π-π EDA might be an important factor in the sorption of TYL and SMT on HA. Results of Fourier transform infrared (FT-IR) and (13)C-nuclear magnetic resonance (NMR) analysis further demonstrated that carboxyl groups and O-alkyl structures in the HA could interact with TYL and SMT via ionic interactions and H bonds, respectively. Overall, this work gives new insights into the mechanisms of sorption of TYL and SMT on HA and hence aids us in assessing the environmental risk of TYL and SMT under diverse conditions. Copyright © 2015. Published by Elsevier B.V.

  6. Novel humic acid-bonded magnetite nanoparticles for protein immobilization.

    Science.gov (United States)

    Bayrakci, Mevlut; Gezici, Orhan; Bas, Salih Zeki; Ozmen, Mustafa; Maltas, Esra

    2014-09-01

    The present paper is the first report that introduces (i) a useful methodology for chemical immobilization of humic acid (HA) to aminopropyltriethoxysilane-functionalized magnetite iron oxide nanoparticles (APS-MNPs) and (ii) human serum albumin (HSA) binding to the obtained material (HA-APS-MNPs). The newly prepared magnetite nanoparticle was characterized by using Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and elemental analysis. Results indicated that surface modification of the bare magnetite nanoparticles (MNPs) with aminopropyltriethoxysilane (APS) and HA was successfully performed. The protein binding studies that were evaluated in batch mode exhibited that HA-APS-MNPs could be efficiently used as a substrate for the binding of HSA from aqueous solutions. Usually, recovery values higher than 90% were found to be feasible by HA-APS-MNPs, while that value was around 2% and 70% in the cases of MNPs and APS-MNPs, respectively. Hence, the capacity of MNPs was found to be significantly improved by immobilization of HA. Furthermore, thermal degradation of HA-APS-MNPs and HSA bonded HA-APS-MNPs was evaluated in terms of the Horowitz-Metzger equation in order to determine kinetic parameters for thermal decomposition. Activation energies calculated for HA-APS-MNPs (20.74 kJmol(-1)) and HSA bonded HA-APS-MNPs (33.42 kJmol(-1)) implied chemical immobilization of HA to APS-MNPs, and tight interactions between HA and HA-APS-MNPs. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. An estimation of influence of humic acid and organic matter originated from bentonite on samarium solubility

    International Nuclear Information System (INIS)

    Kanaji, Mariko; Sato, Haruo; Sasahira, Akira

    1999-10-01

    Organic acids in groundwater are considered to form complexes and increase the solubility of radionuclides released from vitrified waste in a high-level radioactive waste (HLW) repository. To investigate whether the solubility of samarium (Sm) is influenced by organic substances, we measured Sm solubility in the presence of different organic substances and compared those values with results from thermodynamic predictions. Humic acid (Aldrich) is commercially available and soluble organic matter originated from bentonite were used as organic substances in this study. Consequently, the solubility of Sm showed a tendency to apparently increase with increasing the concentration of humic acid, but in the presence of carbonate, thermodynamic predictions suggested that the dominant species are carbonate complexes and that the effect of organic substances are less than that of carbonate. Based on total organic carbon (TOC), the increase of Sm solubility measured with humic acid (Aldrich) was more significant than that in the case with soluble organic matter originated from bentonite. Since bentonite is presumed to include also simple organic matters of which stability constant for forming complexes is low, the effect of soluble organic matter originated from bentonite on the solubility of Sm is considered to be less effective than that of humic acid (Aldrich). Experimental values were compared with model prediction, proposed by Kim, based on data measured in a low pH region. Tentatively we calculated the increase in Sm solubility assuming complexation with humic acid. Trial calculations were carried out on the premise that the complexation reaction of metal ion with humic acid is based on neutralization process by 1-1 complexation. In this process, it was assumed that one metal ion coordinates with one unit of complexation sites which number of proton exchange sites is equal to ionic charge. Consequently, Kim's model indicated that carbonate complexes should be dominant

  8. Complexation behavior of Np(IV) and humic acid

    International Nuclear Information System (INIS)

    Iijima, Kazuki; Tobitsuka, Sachiko; Kohara, Yukitoshi

    2004-04-01

    Complexation behavior between humic acid (HA), which is one of the natural organic matter in groundwater, and tetravalent neptunium (Np(IV)) was investigated by batch type complexation experiments and solvent extraction by TTA xylene, focused on the effect of concentration and molecular weight of HA. In addition, proton dissociation behavior from HA was evaluated by acid-base titration and its results was used for the calculation of stability constant of Np(IV) and HA complex. The results of titration of HA was analysed based on NICA-Donnan model and parameters used for evaluation of proton dissociation behavior were calculated. The charge density of HA in pH 8, which is necessary for calculation of stability constant, was evaluated as -4.35 meq/g. The complexation experiments were carried out under the conditions as follows; 1x10 -5 mol/l of initial Np concentration, from 5 to 500 mg/l of HA concentration, pH 8, in the 0.1 mol/l NaClO 4 , and 0.05 mol/l Na 2 S 2 O 4 as reductant to keep Np as tetravalent. As a result, in the presence of 5 mg/l of HA, total concentration of Np was increased at least one order of magnitude higher than in the case without HA. All added Np existed as soluble species in the presence of more than 50 mg/l of HA. Np in the solution was fractionated by solvent extraction using TTA-xylene as follows; 1) extractable Np into the organic phase, 2) non-extractable Np remained in the inorganic phase, and 3) precipitated Np. These were considered as 1) free Np(VI) or weakly binded Np(IV) and 3) strongly binded Np(IV), while 2) Np(IV)-fulvic acid complex could be suggested. Consequently, stability constant, log β α =26.31, was obtained. In addition, compared with Am(III) or Np(V), accessible site in the HA for Np(IV) seems to be quite limited. (author)

  9. Acid-base properties of humic and fulvic acids formed during composting.

    Science.gov (United States)

    Plaza, César; Senesi, Nicola; Polo, Alfredo; Brunetti, Gennaro

    2005-09-15

    The soil acid-base buffering capacity and the biological availability, mobilization, and transport of macro- and micronutrients, toxic metal ions, and xenobiotic organic cations in soil are strongly influenced by the acid-base properties of humic substances, of which humic and fulvic acids are the major fractions. For these reasons, the proton binding behavior of the humic acid-like (HA) and fulvic acid-like (FA) fractions contained in a compost are believed to be instrumental in its successful performance in soil. In this work, the acid-base properties of the HAs and FAs isolated from a mixture of the sludge residue obtained from olive oil mill wastewater (OMW) evaporated in an open-air pond and tree cuttings (TC) at different stages of composting were investigated by a current potentiometric titration method and the nonideal competitive adsorption (NICA)-Donnan model. The NICA-Donnan model provided an excellent description of the acid-base titration data, and pointed out substantial differences in site density and proton-binding affinity between the HAs and FAs examined. With respect to FAs, HAs were characterized by a smaller content of carboxylic- and phenolic-type groups and their larger affinities for proton binding. Further, HAs featured a greater heterogeneity in carboxylic-type groups than FAs. The composting process increased the content and decreased the proton affinity of carboxylic- and phenolic-type groups of HAs and FAs, and increased the heterogeneity of phenolic-type groups of HAs. As a whole, these effects indicated that the composting process could produce HA and FA fractions with greater cation binding capacities. These results suggest that composting of organic materials improves their agronomic and environmental value by increasing their potential to retain and exchange macro- and micronutrients, and to reduce the bioavailability of organic and inorganic pollutants.

  10. Growth of silver catfish ( Rhamdia quelen exposed to acidic pH at different humic acid levels

    Directory of Open Access Journals (Sweden)

    Silvio Teixeira da Costa

    2016-06-01

    Full Text Available ABSTRACT: Humic substances are organic compounds that possess high molecular weight and are formed by the decomposition of plant materials. Humic substances comprise humic acids, fulvic acids and humin. Humic acids (HA have shown to be able to provide some protection to biological membranes of fish in water with low pH, replacing the protective action of Ca2+. Thus, this studyaimed to observe growth of silver catfish ( Rhamdia quelen juveniles exposed to pHs 5.5 and 6.5 and to different levels of HA: 0, 10, 25 and 50mg L-1. Results showed that, irrespective of pH, HA was highly detrimental to silver catfish growth, since the higher the concentration of HA, the lower the weight gain and feed intake, resulting in lower biomass and lower specific growth rate of juveniles. Hence, HA is extremely damaging to the performance of silver catfish juveniles in the tested concentrations.

  11. The role of humic and fulvic acids in the phototransformation of phenolic compounds in seawater

    Energy Technology Data Exchange (ETDEWEB)

    Calza, P., E-mail: paola.calza@unito.it; Vione, D.; Minero, C.

    2014-09-15

    Humic substances (HS) are known to act as photosensitizers toward the transformation of pollutants in the surface layer of natural waters. This study focused on the role played by HS toward the transformation of xenobiotics in seawater, with the purpose of assessing the prevailing degradation routes. Phenol was chosen as model xenobiotic and its transformation was investigated under simulated sunlight in the presence of terrestrial or marine humic and fulvic acids, in pure water at pH 8, artificial seawater (ASW) or natural seawater (NSW). The following parameters were determined: (1) the phenol degradation rate; (2) the variation in HS concentration with irradiation time; (3) the production of transformation products; (4) the influence of iron species on the transformation process. Faster transformation of phenol was observed with humic acids (HA) compared to fulvic acids (SRFA), and transformation induced by both HA and SRFA was faster in ASW than that in pure water. These observations can be explained by assuming an interplay between different competing and sometimes opposite processes, including the competition between chloride, bromide and dissolved oxygen for reaction with HS triplet states. The analysis of intermediates formed in the different matrices under study showed the formation of several hydroxylated (hydroquinone, 1,4-benzoquinone, resorcinol) and condensed compounds (2,2′-bisphenol, 4,4′-bisphenol, 4-phenoxyphenol). Although 1,4-benzoquinone was the main transformation product, formation of condensed molecules was significant with both HA and SRFA. Experiments on natural seawater spiked with HS confirmed the favored formation of condensed products, suggesting a key role of humic matter in dimerization reactions occurring in saline water. - Highlights: • Phenol transformation in seawater can be photosensitized by humic substances. • Dimeric species are peculiar intermediates formed in the process. • Phenol degradation occurred faster with

  12. Behavior of aluminum adsorption in different Compost-Derived humic acids

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Yong-Hong; Su, Po-Hsin [Kaohsiung District Agricultural Research and Extension Station, Pingtung (China)

    2010-10-15

    Humic acid plays an important role in the distribution of heavy metals in the environment. The aims of this study were conducted to evaluate the spectroscopic characteristics and aluminum (Al) adsorption of humic acids which were extracted from four composts. The functional groups were determined by Fourier transform infrared spectroscopy (FTIR) and solid-state {sup 13}C nuclear magnetic resonance spectroscopy ({sup 13}C-NMR). The results showed that the aromatic groups were all found in the humic acids of the four composts, and the surface of humic acids included carboxylic group, hydroxylic group, and amino group. The experiment of Al adsorption was described by Freundlich equation. It showed that the adsorption of Al by humic acid from compost of cattle manure was higher, but that from the compost of pig manure, lemon manure, tea manure in equal preparation was lower. The adsorptive behavior was different due to the interaction by functional groups (-OH and -COOH) with Al. These results can describe the fate and transportation of Al in the soil of different organic fertilizer. (Copyright copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  13. The effects of humic acid on nutrient status yield and quality of tomato

    Directory of Open Access Journals (Sweden)

    Elif Işıl DEMİRTAŞ

    2014-06-01

    Full Text Available In order to increase organic matter content of soil, humic acid application is the most economic and fast method. In this study, the effects of humic acid and their dosages (0, 4, 8, 12, 16 and 20 L da-1 on nutritional, status of tomato and yield-quality were investigated. During the growing period, a dose of NPK was applied through drip irrigation. The experiment was carried out according to randomized complete block design with four replications under greenhouse conditions in 2011-2013 autumn tomato growing season. In order to determine effects of humic acid, plant and leaves fruit were analyzed during the experiment. The results of analysis showed that increases of N, P, K, Fe, Cu content of tomato leaves was found important whereas Ca, Mg, Mn, Zn and B content was not important statistically. The effect of humic acid+NPK applications on fruit quality of tomato was positive. Fruit yield was increased by humic acid applications compared to control.

  14. Impact of humic/fulvic acid on the removal of heavy metals from aqueous solutions using nanomaterials: a review.

    Science.gov (United States)

    Tang, Wang-Wang; Zeng, Guang-Ming; Gong, Ji-Lai; Liang, Jie; Xu, Piao; Zhang, Chang; Huang, Bin-Bin

    2014-01-15

    Nowadays nanomaterials have been widely used to remove heavy metals from water/wastewater due to their large surface area and high reactivity. Humic acid (HA) and fulvic acid (FA) exist ubiquitously in aquatic environments and have a variety of functional groups which allow them to complex with metal ions and interact with nanomaterials. These interactions can not only alter the environmental behavior of nanomaterials, but also influence the removal and transportation of heavy metals by nanomaterials. Thus, the interactions and the underlying mechanisms involved warrant specific investigations. This review outlined the effects of HA/FA on the removal of heavy metals from aqueous solutions by various nanomaterials, mainly including carbon-based nanomaterials, iron-based nanomaterials and photocatalytic nanomaterials. Moreover, mechanisms involved in the interactions were discussed and potential environmental implications of HA/FA to nanomaterials and heavy metals were evaluated. © 2013.

  15. Crassulacean acid metabolism in submerged aquatic plants

    Science.gov (United States)

    Keeley, Jon E.; Sybesme, C.

    1984-01-01

    CO2-fixation in the dark is known to occur in various organs of many plants. However, only in species possessing crassulacean acid metabolism (CAM) does dark CO2-fixation contribute substantially to the carbon economy of the plant. Until very recently CAM was known only from terrestrial species, largely drought adapted succulents. The discovery of CAM in the submerged aquatic fern ally Isoetes howellii (Isoetaceae)(Keeley 1981) adds a new dimension to our understanding of crassulacean acid metabolism. In this paper I will summarize 1) the evidence of CAM in Isoetes howellii, 2) the data on the distribution of CAM in aquatic species, and 3) the work to date on the functional significance of CAM in aquatic species.

  16. Influence of Humic Acid on 1-Aminopyrene Ecotoxicity During Solar Photolysis Process

    Directory of Open Access Journals (Sweden)

    Huey-Min Hwang

    2002-11-01

    Full Text Available Abstract: 1-Aminopyrene (1-AP, a polycyclic aromatic hydrocarbons (PAH compound, is a major metabolite during biotransformation of 1-nitropyrene by microflora in natural environment and in the guts of animals and humans. Under UV-A irradiation, 1-AP has been shown to cause light-induced DNA single strand cleavage. Humic acids (HA in aquatic ecosystems can influence the bioavailability, toxicity, and fate of organic xenobiotics. Therefore, photochemical fate and effect of PAH in natural aquatic environment may differ significantly across sites. The objectives of this study are to assess the time course (TC; 18 and 90 minutes influence of HA (0, 20, and 60 ppm on microbial ecotoxicity of 1-AP (0 and 10 μM during solar photolysis process (PP. Microbial ecotoxicity of 1-AP during different time courses in the presence and absence of HA was measured with spread plate counting and microbial mineralization of 14C-D-glucose. The experimental results were analyzed as factorial arrangements of treatment in a complete randomized design using General Linear Model by SAS. LSMEANS was used to separate means or combination of means. Significant effect on glucose mineralization was found by the following treatment interactions 1-AP*TC, 1-AP*PP, TC*PP, HA*1-AP*TC, HA*1-AP*PP, and HA*1-AP*TC*PP. The treatment interaction HA*1-AP was the only one affecting spread plate counting. In the groups exposed to 1-AP (10 μM, microbial heterotrophic mineralization of 14C-D-glucose was significantly inhibited in the presence of HA in light and in darkness. Exposure to HA in light and darkness, however, did not necessarily inhibit bacterial viability at the HA concentration range assayed. Therefore, inhibition on microbial activity could have been caused by multiple factors, instead of toxicity of HA alone.

  17. Humic acid batteries derived from vermicomposts at different C/N ratios

    Science.gov (United States)

    Shamsuddin, R. M.; Borhan, A.; Lim, W. K.

    2017-06-01

    Humic acid is a known fertilizer derived from decomposed organic matters. Organic wastes are normally landfilled for disposal which had contributed negatively to the environment. From waste-to-wealth perspective, such wastes are potential precursors for compost fertilizers. When worms are added into a composting process, the process is termed as vermicomposting. In this work, humic acid from vermicompost derived from campus green wastes was developed into a battery. This adds value proposition to compost instead of being traditionally used solely as soil improver. This research work aimed to study the correlation between electrical potential generated by humic acid at different Carbon to Nitrogen (C/N) ratios of vermicompost at 20, 25, 30 and 35. The temperature and pH profiles of composting revealed that the compost was ready after 55 days. The humic acid was extracted from compost via alkaline extraction followed by precipitation in a strong acid. The extracted humic acid together with other additives were packed into a compartment and termed as vermibattery. Another set of battery running only on the additives was also prepared as a control. The net voltage produced by a single vermibattery cell with Zn and PbO electrodes was in the range of 0.31 to 0.44 V with compost at C/N ratio of 30 gave the highest voltage. The battery can be connected in series to increase the voltage generation. Quality assessment on the compost revealed that the final carbon content is between 16 to 23 wt%, nitrogen content of 0.4 to 0.5 wt%, humic acid yield of 0.7 to 1.5 wt% and final compost mass reduction of 10 to 35 wt%. Composting campus green wastes carries multi-fold benefits of reducing labour requirement, generating fertilizer for campus greenery and green battery construction.

  18. Characterization of aquatic humic substances and their metal complexes by immobilized metal-chelate affinity chromatography on iron(III)-loaded ion exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Burba, P.; Jakubowski, B.; Kuckuk, R. [Institut fuer Spektrochemie und Angewandte Spektroskopie e.V., Dortmund (Germany); Kuellmer, K.; Heumann, K.G. [Mainz Univ. (Germany). Inst. fuer Anorganische Chemie und Analytische Chemie

    2000-12-01

    The analytical fractionation of aquatic humic substances (HS) by means of immobilized metal-chelate affinity chromatography (IMAC) on metal-loaded chelating ion exchangers is described. The cellulose HYPHAN, loaded with different trivalent ions, and the chelate exchanger Chelex 100, loaded to 90% of its capacity with Fe(III), were used. The cellulose HYPHAN, loaded with 2% Fe(III), resulted in HS distribution coefficients K{sub d}of up to 10 {sup 3.7} mL/g at pH 4.0 continuously decreasing down to 10 {sup 1.5} at pH 12, which were appropriate for HS fractionation by a pH-depending chromatographic procedure. Similar distribution coefficients K {sub d} were obtained for HS sorption onto Fe(III)-loaded Chelex 100. On the basis of Fe-loaded HYPHAN both, a low-pressure and high-pressure IMAC technique, were developed for the fractionation of dissolved HS applying a buffer-based pH gradient for their gradual elution between pH 4.0 and 12.0. By coupling the Chelex 100 column under high-pressure conditions with an inductively coupled plasma mass spectrometer an on-line characterization of HS metal species could be achieved. Using these fractionation procedures a number of reference HS were characterized. Accordingly, the HA (humic acids) and FA (fulvic acids) studied could be discriminated into up to 6 fractions by applying cellulose HYPHAN, significantly differing in their Cu(II) complexation capacity but hardly in their substructures assessed by conventional FTIR. In the case of using Chelex 100 exchanger resin two major UV active HS fractions were obtained, which significantly differ in their complexation properties for Cu(II) and Pb(II), respectively. (orig.)

  19. Interaction between uranium and humic acid (II): complexation, precipitation and migration behavior of U(VI) in the presence of humic substances

    International Nuclear Information System (INIS)

    Liao Jiali; Li Bing; Yang Yuanyou; Jin Jiannan; Liu Ning; Wen Wei; Zhang Dong; Kang Houjun; Yang Yong

    2013-01-01

    The complexation, precipitation, and migration behavior of uranium in the presence of humic acid (HA) or fulvic acid (FA) were investigated by cation exchange, ultrafiltration and dynamic experiment, respectively. The results showed that (i) complex equilibrium between the uranium and humic substances was achieved at approximately 72 h, (ii) the coordination number varied from 1:1 to 1:2 (U(VI): humic acid) as pH increased from 3 to 6; and (iii), while the complex stability constant decreased when temperature increased, but increased with pH value. We found that the precipitation of uranyl could only be observed in presence of HA, and the precipitation was influenced by conditions, such as pH, uranium concentration, temperature, and the HA concentration. The maximum precipitation proportion up to 60% could be achieved in the condition of 40 mg/L HA solution at pH 6. We further observed that the migration behavior of uranium in soil in the presence of humic acid (HA) or fulvic acid (FA) was different from that in the presence of inorganic colloid, and the effect of humic substances (HS) was limited. (authors)

  20. Speciation of aquatic Hg{sup 2+} in humic substances by time differential perturbed angular correlation

    Energy Technology Data Exchange (ETDEWEB)

    Franke, K.; Kupsch, H. [Universitat Leipzig, (Germany). Institut fuer Geophysik and Geologie; Troger, W.; Butz, T. [Universitat Leipzig, (Germany). Institut fuer Experimentelle Physik II

    1997-10-01

    Humic substances are ubiquitous in waters and soils and act as complexing agents for different heavy metals, e.g. Cd, Hg. Toxicity, reactivity, fixation, and migration are therefore strongly influenced by the interactions between heavy metals and humic substances. Humic substances derive from postmortal materials such as rotten plants, have dark colours and usually a molecular weight between 500 and 10.000 Dalton. Complex formation studies with different heavy metal ions indicate at least two different kinds of metal sites. Usually, these studies are restricted to heavy metal concentrations 2 to 3 orders of magnitude higher that the natural heavy metal abundance (i.e. 10{sup -10} molar). This serious limitation can be overcome by the use of suitable radioisotope techniques capable of metal speciation at extreme sensitivity levels such as TDPAC (Time Differential Perturbed Angular Correlation of {gamma}-Rays). Thus, we studied the interaction of heavy metals with humic substances by monitoring the nuclear quadrupole interaction (NQI)of the short-lived radioisotopes {sup 111m}Cd ({tau}{sub l/2} = 49 min) and {sup 199m}Hg ({tau}{sub 1/2} = 43 min) supplied by ISOLDE via {gamma}-{gamma} -TDPAC and compared the {sup 111m}Cd/{sup 199m}Hg-NQIs in humic substances with the known NQI of model compounds (i.e. metal proteins, organometallic compounds). At lowest Hg(II) concentrations (10{sup -10} molar) only linear Hg(ll) coordinations with nitrogen and/or sulfur were observed, with increasing Hg(II) concentration additional distorted trigonal (at 2.5.10{sup -10} molar) and tetrahedral coordinations (at 2.5.10{sup -8} molar) with various ligands show up and start to become dominant at Hg(II) concentrations of 10{sup -7} molar and higher. Contrary to Hg(II), we observed unspecific binding for Cd(lI) in the {sup 111m}Cd-TDPAC experiments only, even in the 10{sup -10} molar concentration range 21 refs., 3 tabs.,3 figs.

  1. Influence of humic acids on the migration behavior of radioactive and non-radioactive substances under conditions close to nature. Synthesis, radiometric determination of functional groups, complexation

    International Nuclear Information System (INIS)

    Pompe, S.; Bubner, M.; Schmeide, K.; Heise, K.H.; Bernhard, G.; Nitsche, H.

    2000-04-01

    The interaction behavior of humic acids with uranium(VI) and the influence of humic substances on the migration behavior of uranium was investigated. A main focus of this work was the synthesis of four different humic acid model substances and their characterization and comparison to the natural humic acid from Aldrich. A radiometric method for the determination of humic acid functional groups was applied in addition to conventional methods for the determination of the functionality of humic acids. The humic acid model substances show functional and structural properties comparable to natural humic acids. Modified humic acids with blocked phenolic OH were synthesized to determine the influence of phenolic OH groups on the complexation behavior of humic acids. A synthesis method for 14 C-labeled humic acids with high specific activity was developed. The complexation behavior of synthetic and natural humic acids with uranium(VI) was investigated by X-ray absorption spectroscopy, laser-induced fluorescence spectroscopy and FTIR spectroscopy. The synthetic model substances show an interaction behavior with uranium(VI) that is comparable to natural humic acids. This points to the fact that the synthetic humic acids simulate the functionality of their natural analogues very well. For the first time the influence of phenolic OH groups on the complexation behavior of humic acids was investigated by applying a modified humic acid with blocked phenolic OH groups. The formation of a uranyl hydroxy humate complex was identified by laserspectroscopic investigations of the complexation of Aldrich humic acid with uranium(VI) at pH7. The migration behavior of uranium in a sandy aquifer system rich in humic substances was investigated in column experiments. A part of uranium migrates non-retarded through the sediment, bound to humic colloids. The uranium migration behavior is strongly influenced by the kinetically controlled interaction processes of uranium with the humic colloids

  2. Aqueous photocatalytic oxidation of lignin and humic acids with supported TiO2

    Directory of Open Access Journals (Sweden)

    Elina Portjanskaja

    2006-01-01

    Full Text Available The photocatalytic oxidation (PCO of UV-irradiated aqueous solutions containing humic acids and lignin was studied. The photocatalyst TiO2 was attached to buoyant hollow glass microspheres and glass plates. A maximum oxidation efficiency as low as 1.1 and 2.54 mg W−1h−1 for humic acids and lignin, respectively, was achieved in neutral and alkaline media with 25 gm−2 of the buoyant catalyst. In acidic media, efficiency was even lower. The photocatalytic efficiency with the photocatalyst attached to glass plates was about 3 to 4 times higher than that for the buoyant catalyst. Ferrous ions added to acidic solutions did not increase the rate of PCO of humic acids. However the addition of Fe2+ ions, up to 0.05 mM, to the lignin solution leads to a dramatic increase, about 25%, in PCO efficiency. A further increase in ferrous ion concentration results in a decrease in the PCO efficiency of lignin. Proceeding most likely by a radical mechanism, the efficiency of PCO of humic acids did not benefit from an excessive presence of hydroxyl radical promoters, such as hydrogen peroxide, although the reaction rate increased. However, PCO of lignin in the acidic medium, where OH.-radical formation is suppressed, benefited from the introduction of hydrogen peroxide due to promoted radical formation.

  3. Aqueous photocatalytic oxidation of lignin and humic acids with supported TiO 2

    Directory of Open Access Journals (Sweden)

    2006-01-01

    Full Text Available The photocatalytic oxidation (PCO of UV-irradiated aqueous solutions containing humic acids and lignin was studied. The photocatalyst TiO 2 was attached to buoyant hollow glass microspheres and glass plates. A maximum oxidation efficiency as low as 1.1 and 2.54 mg W −1 h −1 for humic acids and lignin, respectively, was achieved in neutral and alkaline media with 25 gm −2 of the buoyant catalyst. In acidic media, efficiency was even lower. The photocatalytic efficiency with the photocatalyst attached to glass plates was about 3 to 4 times higher than that for the buoyant catalyst. Ferrous ions added to acidic solutions did not increase the rate of PCO of humic acids. However the addition of Fe 2+ ions, up to 0.05 mM, to the lignin solution leads to a dramatic increase, about 25%, in PCO efficiency. A further increase in ferrous ion concentration results in a decrease in the PCO efficiency of lignin. Proceeding most likely by a radical mechanism, the efficiency of PCO of humic acids did not benefit from an excessive presence of hydroxyl radical promoters, such as hydrogen peroxide, although the reaction rate increased. However, PCO of lignin in the acidic medium, where OH.-radical formation is suppressed, benefited from the introduction of hydrogen peroxide due to promoted radical formation.

  4. Stability constant of the lanthanum complex with humic acid; Constante de estabilidad del complejo de lantano con acido humico

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez R, M.; Solache R, M. J. [ININ, Carretera Mexico-Toluca s/n, Ocoyoacac 52750, Estado de Mexico (Mexico)

    2008-07-01

    The work described here is a study on the formation of trivalent lanthanum complex with humic acid. Commercial humic acid was purified and then characterized by various analytical techniques. The stability constant determined by a radiochemical method has a worth of log {beta}{sub La},{sub AHA} = 13.6. (Author)

  5. Removal of Radium-226 from Radium-Contaminated Soil using Distilled Water and Humic Acid: Effect of pH

    International Nuclear Information System (INIS)

    Phillips, E.; Muhammad Samudi Yasir; Muhamat Omar

    2011-01-01

    Effect of washing solutions' pH removal of radium-226 from radium-contaminated soil using distilled water and humic acid extracted from Malaysian peat soil was studied by batch washing method. The study encompassed the extraction of humic acid and the washing of radium-contaminated soil using distilled water and humic acid solutions of 100 ppm, both with varying pHs in the range of 3 to 11. The radioactivity concentration of radium-226 was determined by gamma spectrometer.The removal of radium-226 was greater when humic acid solutions were used compared to distilled water at the pH range studied and both washing solutions showed greater removal of radium-226 when basic solutions were used. Nevertheless, comparable removal efficiencies were observed when neutral and highly basic humic acid solutions were used. (author)

  6. Effects of humic acid and solution chemistry on the aggregation and dispersion of carboxyl-functionalized carbon black nanoparticles

    Science.gov (United States)

    Hwang, G.; Gomez-Flores, A.; Choi, S.; Han, Y., , Dr; Kim, H.

    2017-12-01

    The influence of humic acid, ionic strength and ionic species on the aggregation and dispersion of carboxyl-functionalized carbon black nanoparticles (CB-NPs) was systemically investigated in aqueous media. The experimental conditions of stability tests were selected to the changes in the solution chemistry (0.1-10 mM NaCl and 0.01-1 mM CaCl2) and in the presence/absence of humic acid (1 and 5 mg L-1) in an aquatic environment. The CB-NPs suspension was more rapidly settled in NaCl solution than in CaCl2. Specifically, in the case of NaCl, the aggregation rate of CB-NPs increased with ionic strength. Contrary, CB-NPs dispersed in CaCl2 were insensitive to the aggregation as the ionic strength increased; that was because specific adsorption of the divalent cation Ca2+ occurred since the zeta potential of the CB-NPs is reversed to a positive charge with increasing of the ionic strength. It was confirmed that humic acid greatly influences the stability of the CB-NPs. In particular, the dispersion of CB-NPs was improved in the whole range of ionic strengths of NaCl as well as of CaCl2. To support the results, the interaction energy between CB-NPs was calculated for each condition by using the classical Derjaguin-Landau-Verwey-Overbeek (DLVO) and modified-DLVO theories. In the presence of humic acid, the improved stability of CB-NPs is attributed to the steric repulsive force.This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2015R1D1A3A01020766), the Ministry of Education (MOE) and National Research Foundation of Korea (NRF) through the Human Resource Training Project for Regional Innovation (2015H1C1A1035930) and Korea Energy and Mineral Resources Engineering Program (KEMREP).

  7. Improvement of Sweet Potato Production as Affected by Potassium and Humic Acids Using 15N Isotopic Dilution Technique

    International Nuclear Information System (INIS)

    Soliman, M.S.; Abdel Aziz, H.A.; Moursy, A.A.

    2014-01-01

    Field experiment was conducted to trace the effects of potassium fertilizer and different levels of humic acid on yield production of sweet potato grown on sandy soil under drip irrigation system. Different characteristics of sweet potato growth i.e. vegetative parameter (Vine, tuber dry matter yield) and quality of tuber constitutes (nutrients uptake) were determined. Results showed that application of 100% potassium fertilizer with humic 2 (contented 70% Humic and 15% Fulvic) induced higher tuber yield than 50% potassium fertilizer and unfertilized treatment. The most effective treatments (H 2 , H 3 and H 0 ) under 100% potassium fertilizer reflected higher tuber dry weight as compared to unfertilized treatment (1.3 kg plot -1 ).The addition of humic 2 had increased N uptake by tuber over those recorded with the other treatments. In this regards, humic 2 , humic 3 , humic 1 and humic 0 accumulated 27.7, 23.4, 19.8g N plot -1 , respectively against 18.4 g N plot -1 for control. Under rate of 100% potassium fertilizer, the effect of humic treatments on N uptake by vine could be arranged as following: H 3 > H 1 > H 2 > H 0 . Potassium uptake by tuber has the same trend where H 2 resulted is the best value among the other humic treatments. It seems that N content of tuber was lower than those of vine. Reversible trend was noticed with K uptake where its content in tuber was higher than vine. This holds true with all humic and non-humic treatments. In general, the percentage fertilizer use efficiency (%FUE) was enhanced by application of humic acid with varying extent

  8. Sequential photochemical and microbial degradation of organic molecules bound to humic acid

    International Nuclear Information System (INIS)

    Amador, J.A.; Zika, R.G.; Alexander, M.

    1989-01-01

    We studied the effects of photochemical processes on the mineralization by soil microorganisms of [2- 14 C]glycine bound to soil humic acid. Microbial mineralization of these complexes in the dark increased inversely with the molecular weight of the complex molecules. Sunlight irradiation of glycine-humic acid complexes resulted in loss of absorbance in the UV range and an increase in the amount of 14 C-labeled low-molecular-weight photoproducts and the rate and extent of mineralization. More than half of the radioactivity in the low-molecular-weight photoproducts appears to be associated with carboxylic acids. Microbial mineralization of the organic carbon increased with solar flux and was proportional to the loss of A 330 . Mineralization was proportional to the percentage of the original complex that was converted to low-molecular-weight photoproducts. Only light at wavelengths below 380 nm had an effect on the molecular weight distribution of the products formed from the glycine-humic acid complexes and on the subsequent microbial mineralization. Our results indicate that photochemical processes generate low-molecular-weight, readily biodegradable molecules from high-molecular-weight complexes of glycine with humic acid

  9. Biotransformation of coal derived humic acids by Basidiomycetes

    Science.gov (United States)

    Klein, O. I.; Kulikova, N. A.; Stepanova, E. V.; Koroleva, O. V.

    2009-04-01

    Introduction Low energetic coals and wastes of coal industry are promising sources for biologically active compounds including humic acids (HA). Aside from evident advantages of biocatalytic approaches for coal slime conversion such as environmental safety and cost efficiency they also could be used for the improving of HAs biological activity [1, 2]. The aim of the present study was to provide molecular characterization of the HAs formed during biotransformation of coal slime by Basidiomycetes under different cultivation conditions. Materials and methods Biotransformation of brown coal from Solncevskoe deposit (Sakhalin, Russia) was performed by liquid surface cultivation of pure culture Coriolus hirsutus 075 (Wulf. Ex. Fr.) Quel. with rich (contained glucose as a carbon source) and poor (without readily available carbon source) nutrition medium. After 30 days of cultivation coal HAs were separated by alkaline extraction followed by dialysis desalting and drying at 50C. HAs derived were characterized using size-exclusion chromatography, Fourier transformed infrared (FTIR) and 13C NMR spectroscopy. Results and discussion Molecular weight distribution of HA was not significantly affected by Basidiomycetes under all cultivation conditions studied in comparison to HAs extracted from non-conversed coal. FTIR spectra of HA obtained were typical for HAs. Biotransformation of coal did not result in appearance of new functional groups. The exception was observed under rich media conditions where absorbance at 1700 cm-1 was determined related to carbonyl groups of carboxyl and ketonic fragments. Therefore, the revealed phenomena could be explained with additional formation of the above carbonyl groups in the course of biotransformation process. Quantification of 13C NMR spectra revealed decrease of aromatic structures in HA extracted from coal after biotransformation under poor media conditions. Also a significant increase in carboxylic fragments content was observed. So

  10. Humic acid and enzymes in canola-based broiler diets: Effects on ...

    African Journals Online (AJOL)

    Gross lesion analysis displayed high prevalence of rickets in boilers fed CMEnz diet compared with all other dietary treatments. Intestinal morphometric parameters demonstrated some dietary differences in the height and width of the intestinal villi and intestinal crypts. In conclusion, inclusion of humic acid in canola-based ...

  11. Humic acid as a model for natural organic matter (NOM) in the ...

    African Journals Online (AJOL)

    Current practices in some water-treatment facilities have reported that natural organic matter (NOM) blocks the adsorption sites of activated carbon resulting in lower geosmin and 2-methylisoborneol (2-MIB) removal. Humic acid has been reported to compete with geosmin and 2-MIB removal in the same way. The removal ...

  12. Effects of extraction period on yield of rice straw compost humic acids

    African Journals Online (AJOL)

    ... terms of chemical and spectral characteristics. HA from rice straw compost can be extracted within 24 h and purification can be done in relatively short time without changing their chemical and spectral properties to produce K-humate. Key words: Humic acids, rice straw compost, spectral characteristics, extraction period, ...

  13. Influence of Humic Acid on the Transport and Deposition of Colloidal Silica under Different Hydrogeochemical Conditions

    Directory of Open Access Journals (Sweden)

    Jingjing Zhou

    2016-12-01

    Full Text Available The transport and deposition of colloids in aquifers plays an important role in managed aquifer recharge (MAR schemes. Here, the processes of colloidal silica transport and deposition were studied by displacing groundwater with recharge water. The results showed that significant amounts of colloidal silica transport occurred when native groundwater was displaced by HA solution. Solution contains varying conditions of ionic strength and ion valence. The presence of humic acid could affect the zeta potential and size of the colloidal silica, which led to obvious colloidal silica aggregation in the divalent ion solution. Humic acid increased colloidal silica transport by formation of non-adsorbing aqueous phase silica–HA complexes. The experimental and modeling results showed good agreement, indicating that the essential physics were accurately captured by the model. The deposition rates were less than 10−8 s−1 in deionized water and monovalent ion solution. Moreover, the addition of Ca2+ and increase of IS resulted in the deposition rates increasing by five orders of magnitude to 10−4 s−1. In all experiments, the deposition rates decreased in the presence of humic acid. Overall, the promotion of humic acid in colloidal silica was strongly associated with changes in water quality, indicating that they should receive greater attention during MAR.

  14. Degradation of humic acid and formation of formaldehyde in PEROXONE processes

    Energy Technology Data Exchange (ETDEWEB)

    Kim, K.W.; Rhee, D.S. [Kangwon National University, Chunchon (Korea)

    2001-02-01

    This research was studied the action of the coupling ozone-hydrogen peroxide on aqueous humic acid. PEROXONE process is enhanced the generation of hydroxyl radicals which is effective for degradation of organic matters. Therefore the changes of UV{sub 254} and TOC were investigated through the change of concentrations, injection time of H{sub 2}O{sub 2}, initial pH of aqueous humic acid and concentrations of radical scavenger as HCO{sub 3}{sup -} in the PEROXONE processes. And the GC/ECD was used to detect the formaldehyde formed by ozonation of humic acid. From the experimental results, concentrations and injection time of H{sub 2}O{sub 2} and initial pH in solution in the PEROXONE processes were very important for enhancing the efficiency of degradation in humic acid. The results indicated that removal efficiency of TOC was the highest when concentration of H{sub 2}O{sub 2} was 5 mg/L, injection time of H{sub 2}O{sub 2} was 5 minutes and initial pH in solution was 10.5. And presence of alkalinity in solution was reduced the efficiency of treatment. The formaldehyde were formed less PEROXONE processes than only ozone. When initial pH in solution were changed from 3.5 to 10.5, the formaldehyde were formed the highest concentration at pH 5. (author). 18 refs., 12 figs.

  15. Impact of the application of humic acid and sodium nitroprusside on ...

    African Journals Online (AJOL)

    Nickel (Ni) is an essential micronutrient for plants but in high concentrations may turn toxic. This paper discusses the potential role of humic acid (HA) and sodium nitroprusside in modulating or preventing oxidative stress in rice plants. Three genes [superoxide dismutase (SOD) glutathione reductase (GR) and ascorbate ...

  16. Bioremoval of humic acid from water by white rot fungi: exploring the removal mechanisms

    NARCIS (Netherlands)

    Zahmatkesh, M.; Spanjers, H.L.F.M.; Toran, M. J.; Blánquez, P.; van Lier, J.B.

    2016-01-01

    © 2016, The Author(s).Twelve white rot fungi (WRF) strains were screened on agar plates for their ability to bleach humic acid (HA). Four fungal strains were selected and tested in liquid media for removal of HA. Bioremediation was investigated by HA color removal and changes in the concentration

  17. Photodegradation of bisphenol A in simulated lake water containing algae, humic acid and ferric ions

    Energy Technology Data Exchange (ETDEWEB)

    Peng Zhang' e [School of Resources and Environmental Science, Wuhan University, Wuhan 430079 (China)]. E-mail: zhepeng@126.com; Wu Feng [School of Resources and Environmental Science, Wuhan University, Wuhan 430079 (China)]. E-mail: fengwu@whu.edu.cn; Deng Nansheng [School of Resources and Environmental Science, Wuhan University, Wuhan 430079 (China)]. E-mail: nsdengwhu@163.com

    2006-12-15

    The photodegradation of bisphenol A (BPA), a suspected endocrine disruptor (ED), in simulated lake water containing algae, humic acid and Fe{sup 3+} ions was investigated. Algae, humic acid and Fe{sup 3+} ions enhanced the photodegradation of BPA. Photodegradation efficiency of BPA was 36% after 4 h irradiation in the presence of 6.5 x 10{sup 9} cells L{sup -1} raw Chlorella vulgaris, 4 mg L{sup -1} humic acid and 20 {mu}mol L{sup -1} Fe{sup 3+}. The photodegradation efficiency of BPA was higher in the presence of algae treated with ultrasonic than that without ultrasonic. The photodegradation efficiency of BPA in the water only containing algae treated with ultrasonic was 37% after 4 h irradiation. The algae treated with heating can also enhance the photodegradation of BPA. This work helps environmental scientists to understand the photochemical behavior of BPA in lake water. - Algae, humic acid and ferric ions can induce the photodegradation of bisphenol A in an aqueous environment.

  18. Impact of the application of humic acid and sodium nitroprusside on ...

    African Journals Online (AJOL)

    Daniel

    agricultural production, the use of humic acid can also accelerate remediation of contaminated soil by heavy metals (Xu et al., 2010). In the case of the SNP the number of studies that have examined the exogenous NO effects on reducing heavy metal toxicity in plants has increased. Application of SNP under different heavy ...

  19. Humic Acid-Like Material from Sewage Sludge Stimulates Culture Growth of Ectomycorrhizal Fungi in Vitro

    Czech Academy of Sciences Publication Activity Database

    Hršelová, Hana; Soukupová, Lucie; Gryndler, Milan

    2007-01-01

    Roč. 52, č. 6 (2007), s. 627-630 ISSN 0015-5632 R&D Projects: GA ČR GA526/06/0540 Institutional research plan: CEZ:AV0Z50200510 Keywords : ectomycorrhizal basidiomycetes * sewage sludge * humic-acid-like materials Subject RIV: EE - Microbiology, Virology Impact factor: 0.989, year: 2007

  20. Preparative yield and properties of humic acids obtained by sequential alkaline extractions

    Science.gov (United States)

    Kholodov, V. A.; Yaroslavtseva, N. V.; Konstantinov, A. I.; Perminova, I. V.

    2015-10-01

    The preparative yield, composition, and structure of humic acids obtained by sequential alkaline extractions from two soils (a soddy-podzolic soil under forest and a typical chernozem in treatment with permanent black fallow of a long-term experiment since 1964) have been studied. The preparative yield of humic acids from the first extraction is 0.40 and 0.94% for the soddy-podzolic soil (Retisols) and the chernozem, respectively. The preparative yield from the second extraction is lower by several times, and the yield from the third extraction is lower by an order of magnitude. The study of the obtained preparations by elemental analysis, gel-permeation chromatography, and 13C NMR spectroscopy has shown insignificant changes in the elemental, molecular-weight, and structural-group composition of humic acids among the extractions. It has been supposed that this is related to the soil features: typical climatic factors for the formation of soil subtype in the case of soddy-podzolic soil and the land use in the long-term experiment in the case of typical chernozem. It has been concluded that that a single extraction is sufficient for the separation of humic acids and the preparation of a representative sample.

  1. Influence of humic acid on algal uptake and toxicity of ionic silver.

    Science.gov (United States)

    Chen, Zhongzhi; Porcher, Céline; Campbell, Peter G C; Fortin, Claude

    2013-08-06

    The biogeochemical cycle of silver has been profoundly disturbed by various anthropogenic activities. To better understand the relationship among silver speciation, bioavailability, and toxicity in freshwaters, we have studied the short-term uptake of silver by two species of green algae, Chlamydomonas reinhardtii and Pseudokirchneriella subcapitata, in the presence or absence of a well-characterized humic acid (Suwannee River Humic Acid, SRHA). The free Ag(+) concentrations in the exposure solutions were determined using an equilibrium ion-exchange technique. According to the biotic ligand model, for a given free metal ion concentration, metal uptake should remain the same in the presence or absence of humic acid. However, short-term silver uptake in the presence of SRHA was greater than anticipated on the basis of free Ag(+) concentration. Subsequent determination of silver subcellular distribution revealed that significantly more silver was present in the "cell debris" fraction (known to contain the cell wall and fragmented membranes) in the presence of SRHA than in its absence. Finally, this increase in silver uptake in the presence of humic acid did not result in decreased algal growth. These results suggest that the increase in silver uptake observed in the presence of SRHA is surface-bound, not truly internalized.

  2. Effects of calcium and humic acid treatment on the growth and ...

    African Journals Online (AJOL)

    Humic acid (HA) may facilitate plant growth by improving the nutrient uptake as well as through hormonal effects. Studies were conducted to investigate the effect of a mixture of calcium and HA on Oriental lily, which is sensitive to calcium deficiency. Two levels of Ca (3.5 and 7.0 meq/L) were combined with 500 mg/L HA ...

  3. Interaction between Humic Acid and Lysozyme, Studied by Dynamic Light Scattering and Isothermal Titration Calorimetry

    NARCIS (Netherlands)

    Tan, Wen Feng; Koopal, Luuk K.; Norde, Willem

    2009-01-01

    Interactions of purified Aldrich humic acid (PAHA) with the protein lysozyme (LSZ) are studied with dynamic light scattering and isothermal titration calorimetry by mixing LSZ and PAHA at various mass ratios. In solution LSZ is positive and PAHA is negative at the investigated pH values. Up to

  4. Humic acid and enzymes in canola-based broiler diets: Effects on ...

    African Journals Online (AJOL)

    NWUUser

    2017-10-17

    Oct 17, 2017 ... Abstract. The objective of the study was to investigate the effects of dietary inclusion of humic acid and enzymes on bone development, histomorphology of internal organs and the incidence of rickets in broiler chickens fed canola-based diets. In the study, Cobb 500 broiler chicks were used and the ...

  5. Application of HPLC capacity coefficients to characterize the sorption of polycyclic aromatic compounds to humic acid

    DEFF Research Database (Denmark)

    Nielsen, T.; Helweg, C.; Siigur, K.

    1997-01-01

    The sorption coefficients to humic acid of 46 PAC having a wide range in polarity were compared with the capacity coefficients of the PAC to a non-polar HPLC column material (ODS) and a polar one (Diol). It is shown that polar interactions contribute to the sorption of polar PAC in addition...

  6. Potential origin and formation for molecular components of humic acids in soils

    Science.gov (United States)

    Hatcher, Patrick; DiDonato, Nicole; Waggoner, Derek

    2016-04-01

    Humification is defined as the process by which plant and microbial debris are transformed in to humic substances. Proposed pathways for the formation of humic substances, include the lignin and lignin decomposition theories, the lignin-polyphenol theory as well as the melanoidin pathway. It is generally accepted that a combination of several of these pathways with some modifications may be responsible for producing humic substances. The current study examines humic acids from numerous soil samples to demonstrate their molecular composition. In addition we provide an explanation for the formation of these molecules that introduces a new perspective of the humification process. Our work utilizes advanced analytical techniques such as ESI-FTICR-MS and solid state NMR to more completely characterize humic acids at the molecular level. Methods Humic acids were extracted from soils using 0.5 M NaOH followed by treatment with a Dowex™ ion-exchange resin to remove sodium ions. Solid State 13C NMR spectra were obtained on a Bruker 400 MHz Avance II spectrometer equipped with a 4 mm solid state MAS probe. ESI-FTICR-MS analysis was conducted in the negative ion mode on a Bruker Daltonics 12 Tesla Apex Qe FTICR-MS instrument equipped with an Apollo II ESI source. Results: Soil humic acids from numerous soils were investigated in this study. The molecular formulas calculated from ultrahigh resolution mass spectra of well humified soils fall clearly into two predominant regions consisting of condensed aromatic molecules as well as high H/C, low O/C carboxyl-containing aliphatic molecules (CCAM). In contrast, the spectral data for humic acids from a poorly humified spodosol soil show a less dramatic separation of these regions, with relatively more molecular formula plotting in the lignin-like region and relatively fewer condensed aromatic molecules. From the mass spectral observations made for the humic acids, we can readily discern a relationship based on degree of

  7. Time-dependent uptake and toxicity of nickel to Enchytraeus crypticus in the presence of humic acid and fulvic acid

    NARCIS (Netherlands)

    He, Erkai; Qiu, Hao; Qiu, Rongliang; Rentenaar, Charlotte; Devresse, Quentin; Van Gestel, Cornelis A.M.

    2017-01-01

    The present study aimed to investigate the influence of different fractions of dissolved organic carbon (DOC) on the uptake and toxicity of nickel (Ni) in the soil invertebrate Enchytraeus crypticus after different exposure times. The addition of DOC as humic acid or fulvic acid significantly

  8. Humic Acid-Like and Fulvic Acid-Like Inhibition on the Hydrolysis of Cellulose and Tributyrin

    NARCIS (Netherlands)

    Fernandes, Tania V.; van Lier, Jules B.; Zeeman, Grietje

    2015-01-01

    Enzymatic hydrolysis of complex wastes is a critical step for efficient biogas production in anaerobic digesters. Inhibition of this hydrolytic step was studied by addition of humic acid-like (HAL) and fulvic acid-like (FAL) substances, extracted from maize silage and fresh cow manure, to batch

  9. Humic Acid-Like and Fulvic Acid-Like Inhibition on the Hydrolysis of Cellulose and Tributyrin

    NARCIS (Netherlands)

    Fernandes, T.V.; Lier, van J.B.; Zeeman, Grietje

    2015-01-01

    Enzymatic hydrolysis of complex wastes is a critical step for efficient biogas production in anaerobic digesters. Inhibition of this hydrolytic step was studied by addition of humic acid-like (HAL) and fulvic acid-like (FAL) substances, extracted from maize silage and fresh cow manure, to batch

  10. Effect of Lime, Humic Acid and Moisture Regime on the Availability of Zinc in Alfisol

    Directory of Open Access Journals (Sweden)

    Sushanta Kumar Naik

    2007-01-01

    Full Text Available Lime and humic acid application can play an important role in the availability of zinc in paddy soils. We conducted laboratory incubation experiments on a rice growing soil (Alfisol to determine the effect of lime, humic acid and different moisture regimes on the availability of Zn. Addition of half doses of liming material (powdered lime stone recorded highest values of DTPA-Zn followed by no lime and 100% of lime requirement throughout the incubation period. With the progress of incubation, DTPA-Zn increased slightly during the first week and then decreased thereafter. The highest DTPA-extractable Zn content of 2.85 mg/kg was found in the treatment Zn10 L1/2 at 7 days of incubation, showing 17.3 % increase in DTPA-Zn content over its corresponding treatment of Zn alone (Zn10L0. The DTPA-Zn concentration increased with the application of humic acid compared with no humic acid throughout 35 days of the incubation period and the peak value obtained was 3.12 mg/kg in the treatment Zn10 HA2 at 14 days after incubation, showing 50 % increase in Zn content over its corresponding treatment of Zn alone (Zn10HA0. The application of 0.2% humic acid compared with 0.1% resulted in greater increase in DTPA-Zn concentration in soil application. During the 35 days of incubation, highest values of DTPA-Zn were recorded in soil maintained at saturated compared to water logged conditions. However, under alternate wetting and drying condition the DTPA-Zn content gradually decreased up to 21 days and thereafter increased slowly.

  11. Humic Acid Adsorption Onto Iron Oxide Magnetic Nano Particles in Aquious Solution

    Directory of Open Access Journals (Sweden)

    Maryam Foroghi

    2013-12-01

    Full Text Available Background & Objectives: Humic Acid (HA compounds affects water quality, such as color, taste and odor. The compounds not only react with disinfectants to produce disinfection by-products (DBPs harmful to human health. Iron oxide magnetic nanoparticles (MNPs have a high adsorption capacity to adsorb to organic matter. In this study HA removal by IOMNPs was surveyed in aqueous solutions. Methods:  The effects of pH value, agitation rate, adsorbent dose, contact time and the adsorbate concentration on the adsorption efficiency were studied as critical parameters. In addition, effect of ionic strength on the adsorption process and effluent turbidity was surveyed. The MNPs was characterized by X-ray diffraction. Results: Results revealed that at HA concentration of 10 mg/L, pH 4.5, adsorbent dose of 2.7 g/l, agitation rate of 250 rpm and contact time of 90 min at presence of 0.1 M NaCl as an ionic strength agent, the HA removal reached to about 98%. Also, the turbidity of treated samples was increased with increasing of HA loading. On the other hand, increases of ionic strength resulting in increase of removal efficiency and decrees of effluent turbidity. Conclusion: With increasing HA concentration, adsorption capacity of MNPs was increased and HA removal efficiency was decreased. Increasing of ionic strength leads to increase of removal efficiency and decrease of nano particles release. MNPs are easily attracted to the magnetic field application leads to easy separation from aquatic environment.

  12. Anaerobic degradation of benzene by enriched consortia with humic acids as terminal electron acceptors

    Energy Technology Data Exchange (ETDEWEB)

    Cervantes, Francisco J., E-mail: fjcervantes@ipicyt.edu.mx [Division de Ciencias Ambientales, Instituto Potosino de Investigacion Cientifica y Tecnologica (IPICyT), Camino a la Presa San Jose 2055, Col. Lomas 4a. Seccion, San Luis Potosi, SLP, 78216 Mexico (Mexico); Mancilla, Ana Rosa; Toro, E. Emilia Rios-del [Division de Ciencias Ambientales, Instituto Potosino de Investigacion Cientifica y Tecnologica (IPICyT), Camino a la Presa San Jose 2055, Col. Lomas 4a. Seccion, San Luis Potosi, SLP, 78216 Mexico (Mexico); Alpuche-Solis, Angel G.; Montoya-Lorenzana, Lilia [Division de Biologia Molecular, Instituto Potosino de Investigacion Cientifica y Tecnologica (IPICyT), Camino a la Presa San Jose 2055, Col. Lomas 4a. Seccion, San Luis Potosi, SLP, 78216 Mexico (Mexico)

    2011-11-15

    Highlights: {yields} Enriched consortia were able to couple the anaerobic degradation of benzene to the reduction of humic acids. {yields} Electron-equivalents derived from anaerobic benzene oxidation were highly recovered as reduced humic acids. {yields} Several species from classes {beta}-, {delta}- and {gamma}-Proteobacteria were enriched during the anaerobic degradation of benzene. - Abstract: The anaerobic degradation of benzene coupled to the reduction of humic acids (HA) was demonstrated in two enriched consortia. Both inocula were able to oxidize benzene under strict anaerobic conditions when the humic model compound, anthraquinone-2,6-disulfonate (AQDS), was supplied as terminal electron acceptor. An enrichment culture originated from a contaminated soil was also able to oxidize benzene linked to the reduction of highly purified soil humic acids (HPSHA). In HPSHA-amended cultures, 9.3 {mu}M of benzene were degraded, which corresponds to 279 {+-} 27 micro-electron equivalents ({mu}Eq) L{sup -1}, linked to the reduction of 619 {+-} 81 {mu}Eq L{sup -1} of HPSHA. Neither anaerobic benzene oxidation nor reduction of HPSHA occurred in sterilized controls. Anaerobic benzene oxidation did not occur in soil incubations lacking HPSHA. Furthermore, negligible reduction of HPSHA occurred in the absence of benzene. The enrichment culture derived from this soil was dominated by two {gamma}-Proteobacteria phylotypes. A benzene-degrading AQDS-reducing enrichment originated from a sediment sample showed the prevalence of different species from classes {beta}-, {delta}- and {gamma}-Proteobacteria. The present study provides clear quantitative demonstration of anaerobic degradation of benzene coupled to the reduction of HA.

  13. Anaerobic degradation of benzene by enriched consortia with humic acids as terminal electron acceptors

    International Nuclear Information System (INIS)

    Cervantes, Francisco J.; Mancilla, Ana Rosa; Toro, E. Emilia Rios-del; Alpuche-Solis, Angel G.; Montoya-Lorenzana, Lilia

    2011-01-01

    Highlights: → Enriched consortia were able to couple the anaerobic degradation of benzene to the reduction of humic acids. → Electron-equivalents derived from anaerobic benzene oxidation were highly recovered as reduced humic acids. → Several species from classes β-, δ- and γ-Proteobacteria were enriched during the anaerobic degradation of benzene. - Abstract: The anaerobic degradation of benzene coupled to the reduction of humic acids (HA) was demonstrated in two enriched consortia. Both inocula were able to oxidize benzene under strict anaerobic conditions when the humic model compound, anthraquinone-2,6-disulfonate (AQDS), was supplied as terminal electron acceptor. An enrichment culture originated from a contaminated soil was also able to oxidize benzene linked to the reduction of highly purified soil humic acids (HPSHA). In HPSHA-amended cultures, 9.3 μM of benzene were degraded, which corresponds to 279 ± 27 micro-electron equivalents (μEq) L -1 , linked to the reduction of 619 ± 81 μEq L -1 of HPSHA. Neither anaerobic benzene oxidation nor reduction of HPSHA occurred in sterilized controls. Anaerobic benzene oxidation did not occur in soil incubations lacking HPSHA. Furthermore, negligible reduction of HPSHA occurred in the absence of benzene. The enrichment culture derived from this soil was dominated by two γ-Proteobacteria phylotypes. A benzene-degrading AQDS-reducing enrichment originated from a sediment sample showed the prevalence of different species from classes β-, δ- and γ-Proteobacteria. The present study provides clear quantitative demonstration of anaerobic degradation of benzene coupled to the reduction of HA.

  14. A method to attenuate U(VI) mobility in acidic waste plumes using humic acids

    Energy Technology Data Exchange (ETDEWEB)

    Wan, J.; Dong, W.; Tokunaga, T.K.

    2011-02-01

    Acidic uranium (U) contaminated plumes have resulted from acid-extraction of plutonium during the Cold War and from U mining and milling operations. A sustainable method for in-situ immobilization of U under acidic conditions is not yet available. Here, we propose to use humic acids (HAs) for in-situ U immobilization in acidic waste plumes. Our laboratory batch experiments show that HA can adsorb onto aquifer sediments rapidly, strongly and practically irreversibly. Adding HA greatly enhanced U adsorption capacity to sediments at pH below 5.0. Our column experiments using historically contaminated sediments from the Savannah River Site under slow flow rates (120 and 12 m/y) show that desorption of U and HA were non-detectable over 100 pore-volumes of leaching with simulated acidic groundwaters. Upon HA-treatment, 99% of the contaminant [U] was immobilized at pH < 4.5, compared to 5% and 58% immobilized in the control columns at pH 3.5 and 4.5, respectively. These results demonstrated that HA-treatment is a promising in-situ remediation method for acidic U waste plumes. As a remediation reagent, HAs are resistant to biodegradation, cost effective, nontoxic, and easily introducible to the subsurface.

  15. Humification and Humic Acid Composition of Suspended Soil in Oligotrophous Environments in South Vietnam

    Directory of Open Access Journals (Sweden)

    E. V. Abakumov

    2018-01-01

    Full Text Available Humification is considered to be a global process that is implemented in soils and organic sediments and also in natural water and air. The term “suspended soils” has become increasingly common in recent years. Suspended soils are defined as the part of the organic matter that has not undergone the full decomposition process and has not turned into the humus of terrestrial soils. Suspended soils were shown to contain higher total nitrogen, phosphorus, and potassium contents than the forest soil, but the moisture content in suspended soils was significantly lower. Our study of the structural composition of humic substances in suspended soils was conducted with an aim of evaluating the humification rates and structural composition of humic acids in the suspended soil in tropical forests of South Vietnam. Soil samples from three selected areas were investigated: the soil under phorophytes (mineral soil presented by samples of topsoil of the typical dry savanna landscape and two soils from epiphytous formations. Samples were collected from savanna-type sparse communities, located on oligotrophous plains in Phú Quốc Island (South Vietnam in 2015. General properties of the soil and the elemental composition of suspended soils were determined, and the humic substance chemical composition was evaluated using solid state 13C-NMR. Data obtained showed that the pH of the soils under phorophytes was higher than in the suspended soils; basal respiration did not tend to change indices between soils under phorophytes and suspended soils, but the suspended soil was less enriched by nitrogen than the soil under phorophytes. This can be related to the total amount of organic matter exposed to humification in various soils and to the presence of an essential portion of mineral particles in the soil under phorophytes. Data on elemental composition of the humic acids (HAs indicated that one method of humification is implemented in all three soils that were

  16. Influences of humic and fulvic acids and organic matter on leachate chemistry from acid coal spoil

    International Nuclear Information System (INIS)

    Gentry, C.E.; Davidson, W.H.; Wade, G.L.

    1994-01-01

    Column-leaching experiments were conducted on an acid pyritic coal spoil to determine the influence of acid rain, humic acid (HA), fulvic acid (FA), and undecomposed organic matter (OM) on pH and Al, Fe, Mn, and SO 4 concentrations in the spoil leachate and on the spoil. Simulated acid rain of pH 4.0 was applied for 50 weeks under laboratory conditions to spoil columns modified with 0.5% FA or HA, or 2.0% OM from four forest trees and two herbs. Quality-control methods were used to evaluate treatment effects. Addition of HA and tall fescue leaf material to a Lily, KY, spoil created a greater and longer lasting desirable effect on leachate pH and Al, Fe, Mn, and SO 4 than additions of FA or OM of five other species. Results suggest that revegetation resulting in rapid production of matured soil OM may reduce the amount of some ions commonly leached from acid mine spoils

  17. The Effect of Mycorrhizal Fungi and Humic Acid on Yield and Yield Components of Sunflower

    Directory of Open Access Journals (Sweden)

    Hamideh Veysi

    2017-08-01

    Full Text Available Introduction Cultivated sunflower is one of the largest oilseed crops in the world. Sunflower seed is the third largest source of vegetable oil worldwide, following soybean and canola. Nitrogen is one of the most important elements for crops to achieve optimum yields and quality. Phosphorus (P, next to nitrogen, is often the most limiting nutrient for crop and forage production. Phosphorus availability is controlled by three primary factors: soil pH, amount of organic matter and plant species (Reddy et al., 2003. Arbuscular mycorrhizal fungi are one of the most important microorganisms in majority of the undamaged soils so that about 70% of the soil microbial biomass is formed by the mycelium of these fungi. Mycorrhizal association promotes plant absorption of scarce or immobile minerals, especially phosphorus, resulting in enhanced plant growth. Humic acids are dark brown to black, and are soluble in waterunder neutral and alkaline conditions. They are complex aromatic macromolecules with amino acid, amino sugar, peptide and aliphatic compounds linked to the aromatic groups. Humic acid contains nitrogen, phosphorous, calcium, magnesium, sulphur, copper and zinc (Subramanian et al., 2009. Materials and methods Experiment was conducted as split plot factorial based on randomized block design with three replications in 2011-2012. The main plots consisted of nitrogen and phosphorus application levels (zero percent or no chemical fertilizer application, 50% equivalent to 37.5 kg.ha-1 urea + 25 kg.ha-1 super phosphate triple and 100% equivalent to 75 kg.ha-1 urea + 25 kg.ha-1 super phosphate triple. Two species of mycorrhizal include (G. mosseae and (G. interaradices with three levels of humic acid (0, 8 and 16 kg.ha-1 were placed in subplots. The measured traits were: plant height, seed number per head, head diameter, seed oil content, thousand seed weight and seed yield. The data were analyzed using the Mstat-C statistical software. Mean comparison

  18. The Effect of Mycorrhizal Fungi and Humic Acid on Yield and Yield Components of Sunflower

    Directory of Open Access Journals (Sweden)

    Hamideh Veysi

    2017-03-01

    Full Text Available Introduction Cultivated sunflower is one of the largest oilseed crops in the world. Sunflower seed is the third largest source of vegetable oil worldwide, following soybean and canola. Nitrogen is one of the most important elements for crops to achieve optimum yields and quality. Phosphorus (P, next to nitrogen, is often the most limiting nutrient for crop and forage production. Phosphorus availability is controlled by three primary factors: soil pH, amount of organic matter and plant species (Reddy et al., 2003. Arbuscular mycorrhizal fungi are one of the most important microorganisms in majority of the undamaged soils so that about 70% of the soil microbial biomass is formed by the mycelium of these fungi. Mycorrhizal association promotes plant absorption of scarce or immobile minerals, especially phosphorus, resulting in enhanced plant growth. Humic acids are dark brown to black, and are soluble in waterunder neutral and alkaline conditions. They are complex aromatic macromolecules with amino acid, amino sugar, peptide and aliphatic compounds linked to the aromatic groups. Humic acid contains nitrogen, phosphorous, calcium, magnesium, sulphur, copper and zinc (Subramanian et al., 2009. Materials and methods Experiment was conducted as split plot factorial based on randomized block design with three replications in 2011-2012. The main plots consisted of nitrogen and phosphorus application levels (zero percent or no chemical fertilizer application, 50% equivalent to 37.5 kg.ha-1 urea + 25 kg.ha-1 super phosphate triple and 100% equivalent to 75 kg.ha-1 urea + 25 kg.ha-1 super phosphate triple. Two species of mycorrhizal include (G. mosseae and (G. interaradices with three levels of humic acid (0, 8 and 16 kg.ha-1 were placed in subplots. The measured traits were: plant height, seed number per head, head diameter, seed oil content, thousand seed weight and seed yield. The data were analyzed using the Mstat-C statistical software. Mean comparison

  19. Dissolved particulate and sedimentary humic acids in the mangroves and estuarine ecosystem of Goa, west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Sardessai, S.

    Highest concentration of humic acids in all the three forms (dissolved, particulate and sedimentary) was found in the monsoon (June-September) when the salinity was minimum while the lowest concentrations was observed in the premonsoon (February...

  20. Decolorization of humic acids and alkaline lignin derivative by an anamorphic Bjerkandera adusta E59 strain isolated from soil

    Energy Technology Data Exchange (ETDEWEB)

    Kornillowicz-Kowalska, T.; Ginalska, G.; Belcarz, A.; Iglik, H. [University of Life Sciences, Lublin (Poland). Dept. of Microbiology

    2008-07-01

    An anamorphic Bjerkandera adusta R59 strain, isolated from soil, was found to decolorize post-industrial lignin alkaline fraction, humic acids isolated from two kinds of soil and from brown coal. The drop of methoxyphenolic compound levels in liquid B. adusta cultures containing lignin or humic acids was correlated with decolorization of studied biopolymers, which suggests their partial biodegradation. It was shown that this process was Coupled with the induction of secondary metabolism (idiophase), and highest peroxidase activity in culture medium and appearance of aerial mycelium. Decolorization of lignin and humic acids from lessive soil and brown coal depended on glucose presence (cometabolism). Decolorization of humic acid from chernozem was related partially to adsorption by fungal mycelium.

  1. Assessing the Effects of Soil Humic and Fulvic Acids on Germination and Early Growth of Native and Introduced Grass Varieties

    National Research Council Canada - National Science Library

    Senesi, Nicola

    2007-01-01

    The presence of humic acid (HA) generally affects positively and at various extent the germination and early growth of all varieties examined but in some cases negative effects are measured on the early growth...

  2. Removal of 17β-estradiol in a Biological Active Carbon Reactor with Acetic Acid and Humic Acid.

    Science.gov (United States)

    Li, Zhongtian; Stenstrom, Michael K; Li, Xu

    2017-09-01

      The objective of this study is to characterize the removal of 17β-estradiol (E2) and the microbial community of a biologically active carbon (BAC) reactor under acetic acid or humic acid as the primary carbon source. Influent E2 concentration was maintained at 20 μg/L. Higher than 99% removal of E2 was achieved by the BAC reactor. The concentration of E2 increased from below detection limit (carbon source from acetic acid to humic acid in the reactor influent. Meanwhile, effluent estrone concentration increased from 50 ± 15 to 55 ± 15 ng/L after the switch of primary carbon source in the reactor influent. 17β-estradiol degrading bacteria were isolated. Microbial community structures under different nutrient conditions were revealed by high throughput sequencing. The presence of readily biodegradable carbon source such as acetic acid benefited E2 removal in the BAC reactor.

  3. Effects of humic acid-based buffer + cation on chemical characteristics of saline soils and maize growth

    Directory of Open Access Journals (Sweden)

    W. Mindari

    2014-10-01

    Full Text Available Humic acid is believed to maintain the stability of the soil reaction, adsorption / fixation / chelate of cation, thereby increasing the availability of water and plant nutrients. On the other hand, the dynamics of saline soil cation is strongly influenced by the change of seasons that disrupt water and plant nutrients uptake. This experiment was aimed to examine the characteristics of the humic acid from compost, coal, and peat and its function in the adsorption of K+ and NH4+ cations, thus increasing the availability of nutrients and of maize growth. Eighteen treatments consisted of three humic acid sources (compost, peat and coal, two cation additives (K+ and NH4+, and three doses of humic acid-based buffer (10, 20, and 30 g / 3kg, were arranged in a factorial completely randomized with three replicates. The treatments were evaluated against changes in pH, electric conductivity (EC, cation exchange capacity (CEC, chlorophyll content, plant dry weight and plant height. The results showed that the addition of K+ and NH4+ affected pH, CEC, K+, NH4+, and water content of the buffer. Application of humic acid-based buffer significantly decreased soil pH from > 7 to about 6.3, decreased soil EC to 0.9 mS / cm, and increased exchangeable Na from 0.40 to 0.56 me / 100g soil, Ca from 15.57 to 20.21 me/100 g soil, Mg from 1.76 to 6.52 me/100 g soil, and K from 0.05-0.51 me / 100g soil. Plant growth (plant height, chlorophyll content, leaf area, and stem weight at 35 days after planting increased with increasing dose of humic acid. The dose of 2.0g peat humic acid + NH4+ / 3 kg of soil or 30g peat humic acid + K+ / 3 kg of oil gave the best results of maize growth.

  4. Carbon humic acids and their use. Ugleguminovyye kisloty i ikh ispol'zovaniye

    Energy Technology Data Exchange (ETDEWEB)

    Zabramnyy, D.T.; Pobedonosteva, O.I.; Pobedonostseva, N.I.; Umarov, T.Z.

    1980-01-01

    This monograph gives the results of research into the molecular structure of humic acids; certain issues are examined of an applied nature; the data from experimental industrial tests are generalized. Data are generalized which involve questions of the use of humic acids in the form of multiple-ton product. In agriculture, they are used for producing final complex fertilizers and plant growth stimulators; in drilling technology, for improving drilling muds; in the cement industry, for lowering the moisture content of cement raw material sludges. Methods of modifying humates by sulfomethylation are described, and a method for producing coal-alkali reagents directly at drilling and cement firms, based on intensifying the process of interaction of coals with alkali solutions.

  5. Study of humic acids by small-angle X-ray and neutron scattering

    International Nuclear Information System (INIS)

    Timchenko, A.; Trubetskaya, O.; Kihara, H.

    1999-01-01

    Humic acids are an important component of natural ecological system and represent a polydisperse complex of natural biopolymers with molecular masses from several to hundreds kilodaltons. They are both a source of organic compounds and a protector against anthropogenic pollutions of biosphere. The aim of the report is to underline some possibilities of small-angle X-ray and neutron scattering to study HA and their fractions. (author)

  6. The Investigation of Electron Beam Catalytical Oxidation Process Efficiency with Potassium Persulfate in Removal Humic Acid from Aqueous Solutions

    Directory of Open Access Journals (Sweden)

    MT Ghaneian

    2015-05-01

    Results: Based on the results, changes in pH had little effect on the Humic acid removal efficiency. The average, with increasing of pH from 4 to 10, the removal efficiency of humic acid from 72.59% to 73.36% increased, respectively. The results showed that increasing of the dose from 1 to 15 kGy, humic acid removal efficiency increases. Based on results by increasing of persulfate concentration, the removal efficiency increased so that with increasing of concentration of potassium persulfate from 0.1 to 0.5 mmol/100cc, removal efficiency from 69.43% to 83.82% was increased. Kinetic experiments showed that the decomposition of humic acid by electron beam radiation followed the second-order kinetic. Conclusion: The data from this study showed that the aqueous solution containing acid Humic is decomposed effectively by electron beams irradiation. Addition of potassium persulfate can be have significant improvements in removal efficiency of humic acid in the presence of electron beam.

  7. Enhanced PCBs sorption on biochars as affected by environmental factors: Humic acid and metal cations

    International Nuclear Information System (INIS)

    Wang Yu; Wang Lei; Fang Guodong; Herath, H.M.S.K.; Wang Yujun; Cang Long; Xie Zubin; Zhou Dongmei

    2013-01-01

    Biochar plays an important role in the behaviors of organic pollutants in the soil environment. The role of humic acid (HA) and metal cations on the adsorption affinity of polychlorinated biphenyls (PCBs) to the biochars in an aqueous medium and an extracted solution from a PCBs-contaminated soil was studied using batch experiments. Biochars were produced with pine needles and wheat straw at 350 °C and 550 °C under anaerobic condition. The results showed that the biochars had high adsorption affinity for PCBs. Pine needle chars adsorbed less nonplanar PCBs than planar ones due to dispersive interactions and separation. Coexistence of HA and metal cations increased PCBs sorption on the biochars accounted for HA adsorption and cation complexation. The results will aid in a better understanding of biochar sorption mechanism of contaminants in the environment. - Highlights: ► Application of the biochars for PCBs sorption was a new and effective way. ► The biochars had higher adsorption affinity for PCBs in the soil extracted solution. ► Pine needle chars adsorbed less nonplanar PCBs than planar ones. ► Coexisting humic acid or metal cations increased PCBs sorption on the biochars. - The biochars had higher adsorption affinity for PCBs in the extracted soil solution because coexisting humic acid and metal cations increased their sorption.

  8. Effect of rhizobacteria inoculation and humic acid application on canola (Brassica napus L.) crop

    International Nuclear Information System (INIS)

    Ahmad, S.; Duar, I.; Solaimani, S.G.A.; Mahmood, S.

    2016-01-01

    This study investigated eco-friendly approach of utilizing plant growth promoting rhizobacteria (PGPR) and humic acid (HA) as bio-stimulants to improve the growth, yield and nutrition of canola (Brassica napus L.). In this study, we isolated 20 indigenous rhizobacterial strains that were subsequently screened and characterized for their plant growth promoting traits. After that one promising PGPR strain identified as Acinetobacter pittii by 16S rRNA gene sequencing was selected for field trial. The field experiment was conducted using RCB design with split-plot arrangement that was replicated four times. Three levels of humic acid (0, 10 and 20 kg ha-1) as main plot factor and two treatments of PGPR (with and without PGPR) as sub-plot factor were used. Data was recorded on plant height (cm), root dry matter plant-1, number of lateral root plant-1, number of pods plant-1, number of seeds pod-1, 1000 seed weight (g), seed yield(kg ha-1), oil content (%), nitrogen (N), phosphorus (P) and potassium (K) contents and uptake. For most of the above mentioned parameters, significant enhancement was observed with the increment of humic acid, and also PGPR treatments were better than their respective control treatments. Maximum values of these parameters were recorded for the interaction of 20 kg HA ha-1 with the PGPR strain. It can be concluded that integrated application of HA and PGPR is a better strategy to improve nutrition and yield of canola. (author)

  9. Preparation and adsorption behavior for metal ions and humic acid of chitosan derivatives crosslinked by irradiation

    International Nuclear Information System (INIS)

    Zhao Long; Mitomo, H.; Yoshii, F.

    2006-01-01

    Introduction: Removing metal ions and humic acid from water in water treatment has attracted much environment and health interests. Adsorbents, derived from a nature polymer, are desired in the viewpoints of environment-conscious technologies. Recently, some nature materials such as chitin, chitosan and their derivatives have been identified as an attractive option due to their distinctive properties. For an insoluble adsorbent based on these polymers to be obtained over a broad pH range, modification through crosslinking is required. Crosslinking agents such as glutaric dialdehyde and ethylene glycol diglycidyl ether are frequently used for modification. However, these crosslinking agents are not preferred because of their physiological toxicity. Radiation-crosslinking without any additive in the fabrication process results in a high-purity product. In a previous work, we applied ionizing radiation to induce the crosslinking of carboxymethylchitosan under highly concentrated paste-like conditions. The aim of this study is to investigate the adsorption behavior of metal ions, humic acid on irradiation-crosslinked carboxymethylchitosan. Experimental: Irradiation of chitosan samples at paste-like state was done with an electron beam. The solubility test of these crosslinked materials were investigated in acidic, alkaline media, and some organic solvents. Swelling and charged characteristic analyses demonstrated typically pH-sensitive properties of these crosslinked materials. Scanning electron microscopic images showed that the crosslinked samples possessed porous morphological structure. The adsorption studies were carried out by the batch method at room temperature. Adsorption of heavy metal ions (such as Cu 2+ , Cd 2+ ) and humic acid onto crosslinked samples was found to be strongly pH-dependent. Adsorption kinetic studies indicated the rapid removal of metal ions, and humic acid from the aqueous solutions. Also, isothermal adsorption data revealed that Cu 2

  10. Humic acids of vermicompost as an ecological pathway to increase ...

    African Journals Online (AJOL)

    Andres

    2012-02-14

    Feb 14, 2012 ... content, dry-mass content, leaf carbohydrates, protein content and amino-acid content were among the parameters evaluated. ... denaturation of nucleic acids and proteins (Agrawal et al.,. 2002). When these stresses are ..... natural sources for the retention of heavy metals cations. Rev. Iberoam. Polim.

  11. Pyrolysis-mass spectrometry/pattern recognition on a well-characterized suite of humic samples

    Science.gov (United States)

    MacCarthy, P.; DeLuca, S.J.; Voorhees, K.J.; Malcolm, R.L.; Thurman, E.M.

    1985-01-01

    A suite of well-characterized humic and fulvic acids of freshwater, soil and plant origin was subjected to pyrolysis-mass spectrometry and the resulting data were analyzed by pattern recognition and factor analysis. A factor analysis plot of the data shows that the humic acids and fulvic acids can be segregated into two distinct classes. Carbohydrate and phenolic components are more pronounced in the pyrolysis products of the fulvic acids, and saturated and unsaturated hydrocarbons contribute more to the humic acid pyrolysis products. A second factor analysis plot shows a separation which appears to be based primarily on whether the samples are of aquatic or soil origin. ?? 1985.

  12. Removal of humic acid by a new type of electrical hollow-fiber microfiltration (E-HFMF)

    Science.gov (United States)

    Shang, Ran; Deng, Hui-ping; Hu, Jing-yi

    2010-11-01

    Low pressure membrane filtration, such as microfiltration, was widely used in the field of drinking water purification in the past few decades. Traditional microfiltration membranes are not efficient enough in the removal of natural organic matters (NOM) from raw water. Moreover, they tend to be fouled by the NOM and the filtration age of the membranes is thus shrinked. To tackle these problems, a new type of electrical hollow-fiber microfiltration module (E-HFMF) was designed. In the E-HFMF module, the hollow-fiber microfiltration membranes were placed into the radialized electrical field which functioned from the centre to the exterior of the cylindrical cavity. The main goal of the present study was to evaluate the efficiency of E-HFMF to remove the humic acid (HA, one of the main components of NOM). According to the parallel tests compared with the traditional microfiltration, the removal rate of humic acid was raised to 70%˜85% in terms of UV-254 and to 60%˜75% in terms of DOC when filtrating with the E-HFMF, while the removal rates of humic acid were 10%˜20% and 1%˜10% respectively when filtrating with the traditional microfiltration. The negative charged humic acid moved to the anode because of the electrophoresis, so few humic acid could be able to permeate through the membrane. The electrophoresis mobility of the humic acid permeating through the traditional microfiltration decreased by 19%, while the same index from the E-HFMF decreased by 75%. This indicated that the electrophoresis played a significant role on removing the humic acid. According to the gel permeate chromatograph analysis, humic acid aggregated in an electric field and thus forms loose and permeable cake layer on the membrane surface, which also relieved membrane fouling. Meanwhile, the negative charged humic acid migrating to the anode at the center minimized the deposition onto the membrane surface, and eliminated the membrane fouling as a result. During the E-HFMF filtration, the

  13. Conductivity-Dependent Flow Field-Flow Fractionation of Fulvic and Humic Acid Aggregates

    Directory of Open Access Journals (Sweden)

    Martha J. M. Wells

    2015-09-01

    Full Text Available Fulvic (FAs and humic acids (HAs are chemically fascinating. In water, they have a strong propensity to aggregate, but this research reveals that tendency is regulated by ionic strength. In the environment, conductivity extremes occur naturally—freshwater to seawater—warranting consideration at low and high values. The flow field flow fractionation (flow FFF of FAs and HAs is observed to be concentration dependent in low ionic strength solutions whereas the corresponding flow FFF fractograms in high ionic strength solutions are concentration independent. Dynamic light scattering (DLS also reveals insight into the conductivity-dependent behavior of humic substances (HSs. Four particle size ranges for FAs and humic acid aggregates are examined: (1 <10 nm; (2 10 nm–6 µm; (3 6–100 µm; and (4 >100 µm. Representative components of the different size ranges are observed to dynamically coexist in solution. The character of the various aggregates observed—such as random-extended-coiled macromolecules, hydrogels, supramolecular, and micellar—as influenced by electrolytic conductivity, is discussed. The disaggregation/aggregation of HSs is proposed to be a dynamic equilibrium process for which the rate of aggregate formation is controlled by the electrolytic conductivity of the solution.

  14. Advanced characterization of algogenic organic matter, bacterial organic matter, humic acids and fulvic acids.

    Science.gov (United States)

    Chon, Kangmin; Cho, Jaeweon; Shon, Ho Kyong

    2013-01-01

    Advanced characterization techniques of organic matter, including bulk organic characterization, size-exclusion chromatography, three-dimensional excitation-emission matrix, Fourier transform infrared spectroscopy, and fractionations using Amberlite XAD-8/4 resins, were used to investigate differences and similarities in the physicochemical properties of four different organic matter, namely algogenic organic matter (AOM), bacterial organic matter (BOM), Suwanee River humic acids (SRHA) and Suwanee River fulvic acids (SRFA). From the comparison of characteristics of the AOM, BOM, SRHA, and SRFA, it was identified that the specific UV absorbance, molar ratio of organic nitrogen to organic carbon, molecular weight, fluorescence characteristics, functional group compositions, and relative hydrophobicity/hydrophilicity of all the tested organic matter were considerably different from their sources. The SRHA and SRFA were mainly composed of hydrophobic fractions while the AOM and BOM included more hydrophilic fractions than the SRHA and SRFA due to the alcohol and amide functional groups. This indicated that the origin of organic matter in natural waters can be predicted by their physicochemical characteristics, and the source identification of organic matter provides a better understanding of the interactions between the origin of organic matter and water treatment processes (e.g., coagulation and membrane filtration).

  15. Influences of humic acid and fulvic acid on horizontal leaching behavior of anthracene in soil barriers.

    Science.gov (United States)

    Yu, Sheng; Li, Bang-Yu; Chen, Yi-Hu

    2015-12-01

    The influences of humic acid (HA) and fulvic acid (FA) on horizontal leaching behaviors of anthracene in barriers were investigated. Soil colloids (≤1 μm) were of concern because of their abilities of colloid-facilitated transport for hydrophobic organic compounds with soluble and insoluble organic matters. Through freely out of the barriers in the presence of soil colloids with FA added, the higher concentrations of anthracene were from 320 μg L(-1) (D1 and D3) to 390 μg L(-1) (D2 and D4) with 1 to 20 cm in length. The contents of anthracene were distributed evenly at 25 ng g(-1) dry weight (DW) (D1 and D3) and 11 ng g(-1) DW (D2 and D4) in barriers. Therefore, anthracene leaching behaviors were mainly induced by soil colloids with soluble organic matters. The insoluble organic matters would facilitate anthracene onto soil colloids and enhance the movement in and through porous media of soil matrix.

  16. Charge characteristics of humic and fulvic acids: comparative analysis by colloid titration and potentiometric titration with continuous pK-distribution function model.

    Science.gov (United States)

    Bratskaya, S; Golikov, A; Lutsenko, T; Nesterova, O; Dudarchik, V

    2008-09-01

    Charge characteristics of humic and fulvic acids of a different origin (inshore soils, peat, marine sediments, and soil (lysimetric) waters) were evaluated by means of two alternative methods - colloid titration and potentiometric titration. In order to elucidate possible limitations of the colloid titration as an express method of analysis of low content of humic substances we monitored changes in acid-base properties and charge densities of humic substances with soil depth, fractionation, and origin. We have shown that both factors - strength of acidic groups and molecular weight distribution in humic and fulvic acids - can affect the reliability of colloid titration. Due to deviations from 1:1 stoichiometry in interactions of humic substances with polymeric cationic titrant, the colloid titration can underestimate total acidity (charge density) of humic substances with domination of weak acidic functional groups (pK>6) and high content of the fractions with molecular weight below 1kDa.

  17. The thermodynamic stability of hydrogen bonded and cation bridged complexes of humic acid models-A theoretical study

    International Nuclear Information System (INIS)

    Aquino, Adelia J.A.; Tunega, Daniel; Pasalic, Hasan; Haberhauer, Georg; Gerzabek, Martin H.; Lischka, Hans

    2008-01-01

    Hydrogen bonded and cation bridged complexation of poly(acrylic acid) oligomers, representing a model compound for humic acids, with acetic acid and the herbicide (4-chloro-2-methylphenoxy) acetic acid (MCPA) have been studied by means of density functional theory. Solvation effects were computed by means of a combination of microsolvation (explicit insertion of water molecules) and global solvation (polarizable continuum approach). The stability of hydrogen bonded complexes in solution is characterized by a strong competition between solute and solvent molecules. The cation bridged complexes of the negatively charged (deprotonated) ligands were found to be strongly favored explaining the capability of humic acids to fixate anionic species from soil solutions and the ability to form cross-linking structures within the humic acid macromolecules

  18. An innovative zinc oxide-coated zeolite adsorbent for removal of humic acid

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Lingling, E-mail: lasier_wang@hotmail.com [College of Chemical Engineering and Materials, Quanzhou Normal University, Quanzhou 362000, Fujian (China); Environmental Engineering and Science Program, 705 Engineering Research Center, University of Cincinnati, Cincinnati, OH 45221-0012 (United States); Han, Changseok [ORISE Post-doctoral Fellow, The U.S. Environmental Protection Agency, ORD, NRMRL, STD, CPB, 26 W. Martin Luther King Jr. Drive, Cincinnati, OH 45268 (United States); Nadagouda, Mallikarjuna N. [The U.S. Environmental Protection Agency, ORD, NRMRL, WSWRD, WQMB, 26 W. Martin Luther King Jr. Drive, Cincinnati, OH 45268 (United States); Dionysiou, Dionysios D., E-mail: dionysios.d.dionysiou@uc.edu [Environmental Engineering and Science Program, 705 Engineering Research Center, University of Cincinnati, Cincinnati, OH 45221-0012 (United States); Nireas-International Water Research Centre, School of Engineering, University of Cyprus, PO Box 20537, 1678, Nicosia (Cyprus)

    2016-08-05

    Highlights: • An innovative adsorbent was successfully synthesized to remove humic acid. • The adsorbent possessed high adsorption capacity for humic acid. • The adsorption capacity remarkably increased after an acid modification. • The adsorption capacity was proportional to the amount of ZnO coated on zeolite. • Electrostatic interactions are a major factor at the first stage of the process. - Abstract: Zinc oxide (ZnO)-coated zeolite adsorbents were developed by both nitric acid modification and Zn(NO{sub 3}){sub 2}·6H{sub 2}O functionalization of zeolite 4A. The developed adsorbents were used for the removal of humic acid (HA) from aqueous solutions. The synthesized materials were characterized by porosimetry analysis, scanning electron microscopy, X-Ray diffraction analysis, and high resolution transmission electron microscopy. The maximum adsorption capacity of the adsorbents at 21 ± 1 °C was about 60 mgC g{sup −1}. The results showed that the positive charge density of ZnO-coated zeolite adsorbents was proportional to the amount of ZnO coated on zeolite and thus, ZnO-coated zeolite adsorbents exhibited a greater affinity for negatively charged ions. Furthermore, the adsorption capacity of ZnO-coated zeolite adsorbents increased markedly after acid modification. Adsorption experiments demonstrated ZnO-coated zeolite adsorbents possessed high adsorption capacity to remove HA from aqueous solutions mainly due to strong electrostatic interactions between negative functional groups of HA and the positive charges of ZnO-coated zeolite adsorbents.

  19. Humic acids: Structural properties and multiple functionalities for novel technological developments.

    Science.gov (United States)

    de Melo, Bruna Alice Gomes; Motta, Fernanda Lopes; Santana, Maria Helena Andrade

    2016-05-01

    Humic acids (HAs) are macromolecules that comprise humic substances (HS), which are organic matter distributed in terrestrial soil, natural water, and sediment. HAs differ from the other HS fractions (fulvic acid and humins) in that they are soluble in alkaline media, partially soluble in water, and insoluble in acidic media. Due to their amphiphilic character, HAs form micelle-like structures in neutral to acidic conditions, which are useful in agriculture, pollution remediation, medicine and pharmaceuticals. HAs have undefined compositions that vary according to the origin, process of obtainment, and functional groups present in their structures, such as quinones, phenols, and carboxylic acids. Quinones are responsible for the formation of reactive oxygen species (ROS) in HAs, which are useful for wound healing and have fungicidal/bactericidal properties. Phenols and carboxylic acids deprotonate in neutral and alkaline media and are responsible for various other functions, such as the antioxidant and anti-inflammatory properties of HAs. In particular, the presence of phenolic groups in HAs provides antioxidant properties due to their free radical scavenging capacity. This paper describes the main multifunctionalities of HAs associated with their structures and properties, focusing on human health applications, and we note perspectives that may lead to novel technological developments. To the best of our knowledge, this is the first review to address this topic from this approach. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Kinetics of the oxidative hydroxylation of tetraphosphorus in the presence of copper(II) chloride modified by humic (fulvo-) acid

    OpenAIRE

    Zhaksyntay Kairbekov; Dina Akbayeva; Zh. Eshova

    2012-01-01

    It was established that in mild conditions (50-70 oC, РО2= 1 atm) white phosphorus effectively is oxidized by oxygen in water-toluene solutions of copper(II) chloride modified by humic (fulvo-) acid to give mainly phosphoric acid. Humic (fulvo-) acid was extracted from brown coal of domestic deposit Kiyakty. For determination of optimum parameters of fulvo-acid extraction the laboratory experiments were carried out using the method of experiment planning. The kinetics, intermediate and final ...

  1. Quantitative evaluation of noncovalent interactions between polyphosphate and dissolved humic acids in aqueous conditions

    International Nuclear Information System (INIS)

    Fang, Wei; Sheng, Guo-Ping; Wang, Long-Fei; Ye, Xiao-Dong; Yu, Han-Qing

    2015-01-01

    As one kind of phosphorus species, polyphosphate (poly-P) is ubiquitous in natural environments, and the potential interactions between poly-P and humic substances in the sediments or natural waters would influence the fate of poly-P in the environments. However, the mechanism of the interactions has not yet been understood clearly. In this work, the characteristics and mechanisms of the interactions between humic acids (HA) and two model poly-P compounds with various chain lengths have been investigated. Results show that a stable polyphosphate-HA complex would be formed through the noncovalent interactions, and hydrogen bond might be the main driving force for the binding process, which might be formed between the proton-accepting groups of poly-P (e.g., P=O and P–O − ) and the oxygen containing functional groups in HA. Our findings implied that the presence of humic substances in natural waters, soils and sediments would influence the potential transport and/or mobility of environmental poly-P. - Highlights: • Noncovalent interactions between polyphosphate and HA were quantitatively evaluated. • Hydrogen bonding was the main driving force in the interaction between HA and poly-P. • The association played important roles in the environmental fate of poly-P in waters. - Stable polyP-HA complex would be formed through the noncovalent interactions and thus influence the poly-P fates in the natural environments.

  2. Evaluation of Mycorrhizal Fungi, Vermicompost and Humic Acid on Essence Yield and Root Colonization of Fennel

    Directory of Open Access Journals (Sweden)

    I. Akbari

    2016-02-01

    Full Text Available Introduction The main objective of sustainable agriculture is to decrease the off-farm inputs such as chemical fertilizers, increased farm nutrient cycle through reduced tillage and the use of biological and organic fertilizers. Studies on medicinal plants indicates that the use of sustainable farming systems provide the best conditions for the production of these plants. Mycorrhizal fungi, vermicompost and humic acid are samples of biological and organic fertilizer that can be used, to eliminate or substantially reduce the use of chemical inputs in order to increase the quantity, quality and stability of the products. Mycorrhizal fungi are one of the most important rhizosphere microorganisms which have symbiotic relation with root of most crops. Mycorrhizal symbiosis improves the soil physical (through expansion of hyphae of fungus, chemical (through increased absorption of nutrients and biological (the soil food web quality. These fungus increased nutrient uptake, such as phosphorus and some micronutrients, water uptake, reducing the negative effects of environmental stress and increase resistance to pathogens and improve the quality of their host plants. Fennel (Foeniculum vulgare Mill is one of the most important medicinal plants, as the essential oil from the seeds used in a variety of industries, pharmaceutical, food and cosmetic use. Anethole is important component of the essential oil of fennel seed. Materials and Methods This experiment was conducted as a factorial based on randomized complete block design in order to evaluate the effects of vermicompost application, humic acid and mycorrhizal fungi on quantitative and qualitative aspects of fennel yield at experimental farm of Shahrood University during growing season of 1391-92. This experiment includes 12 treatments and 3 applications. Vermicompost levels include: v1 (no application v2 (4 ton ha-1 v3 (8 ton ha-1. Mycorrhizal fungi include: m1 (no inoculation and m2 (inoculation and

  3. Speciation of Aquatic Heavy Metals in Humic Substances by$^{111m}$Cd/$^{199m}$Hg-TDPAC

    CERN Multimedia

    2002-01-01

    Humic substances are ubiquitous in waters and soils and act as complexing agents for different heavy metals, e.g. Cd, Hg. Toxicity, reactivity, fixation and migration are therefore strongly influenced by the interactions between heavy metals and humic substances. Humic substances derive from postmortal materials such as rotten plants, have dark colours and usually a molecular weight between 500 and 10~000 Dalton. Complex formation studies with different heavy metal ions indicate at least two different kinds of metal sites. Usually, these studies are restricted to heavy metal concentrations 2 to 3 orders of magnitude higher than the natural heavy metal abundance (i.e. 10$^{-10}$ molar). This serious limitation can be overcome by the use of suitable radiosotope techniques capable of metal speciation at extreme sensitivity levels such as TDPAC (Time Differential Perturbed Angular Correlation of~$\\gamma$-rays). Thus, we studied the interaction of heavy metals with humic substances by monitoring the nuclear quadru...

  4. Effect of humic acid on the underpotential deposition-stripping voltammetry of copper in acetic acid soil extract solutions at mercaptoacetic acid-modified gold electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Herzog, Gregoire; Beni, Valerio; Dillon, Patrick H.; Barry, Thomas; Arrigan, Damien W.M

    2004-05-24

    Electrochemical measurements were undertaken for the investigation of the underpotential deposition-stripping process of copper at bare and modified gold electrodes in 0.11 M acetic acid, the first fraction of the European Union's Bureau Communautaire de References (BCR) sequential extraction procedure for fractionating metals within soils and sediments. Gold electrodes modified with mercaptoacetic acid showed higher sensitivity for the detection of copper than bare gold electrodes, both in the absence and in the presence of humic acid in acetic acid solutions, using the underpotential deposition-stripping voltammetry (UPD-SV) method. In the presence of 50 mg l{sup -1} of humic acid, the mercaptoacetic acid modified electrode proved to be 1.5 times more sensitive than the bare gold electrode. The mercaptoacetic acid monolayer formed on the gold surface provided efficient protection against the adsorption of humic acid onto the gold electrode surface. Variation of the humic acid concentration in the solution showed little effect on the copper stripping signal at the modified electrode. UPD-SV at the modified electrode was applied to the analysis of soil extract samples. Linear correlation of the electrochemical results with atomic spectroscopic results yielded the straight-line equation y ({mu}g l{sup -1}) = 1.10x - 44 (ppb) (R=0.992, n=6), indicating good agreement between the two methods.

  5. Effect of Humic Acid and Organic Manure Tea on Plant Physiology and Fruit Characteristics of Pepino

    Directory of Open Access Journals (Sweden)

    Jamal Javanmardi

    2017-02-01

    Full Text Available Introduction Pepino (SolanummuricatumAit., a Solanaceous vegetable fruit has been recently introduced to Iran markets. Organic farming is currently the fastest growing agricultural sector worldwide. Although several investigations are available on chemical fertilization of pepino, the knowledge of organic fertilization ismostly lacking. Therefore, at the beginning of introducing pepino plant to Iranian farmers it worth to evaluate the impact of organic fertilization on the productivity, profitability, acceptability and sustainability of farming systemsto this plant. High chemical fertilization of pepinoincreases the vegetative growth over the generative and fruit production. The aim of this investigation was to introduce the possibility of organic production of pepino. Materials and Methods.A two-year experiment was carried out to assess the possibility of organic production of pepino using organic fertilizers. Humistar® organic fertilizer (containing 8.6% humic acid at 50 L/ha and sheep or cow manure teas at 1:10 and 1:5 ratios were used for production of pepino cv. Kanseola to evaluate their effects on the physiology of reproductive stage and some fruit quality characteristics. The experiments were arranged as factorial in a randomized complete block design comprised of 3 replications, each of which 10 plants. Mother plants were obtained from Mashhad Ferdowsi University and incubated in a greenhouse (mean temperature of 25 °C and 60-70% relative humidity for 1 month to proliferate. Cuttings with 2-3 leaves at the top, 3-5 healthy buds and 20 cm length were rooted for 14 days in a rooting media, ( 1:1:2 of field soil, composted leaf and perlite, respectively. Plants were transplanted into the field in 100 × 75 cm spacing after the danger of frost was over. Treatments consisted of two levels of 1:5 and 1:10 (w:w cow or sheep manure teas in combination with two levels of Humistar® organic fertilizer as 0 and 50L/ha levels. Control plants

  6. Characterization of commercial humic acid samples and their impact on growth of fungi and plants

    Directory of Open Access Journals (Sweden)

    Asma Lodhi, Shermeen Tahir, Zafar Iqbal, Ansar Mahmood, Muhammad Akhtar, Tariq Mahmood Qureshi, Muhammad Yaqub and Asif Naeem

    2013-05-01

    Full Text Available Naturally occurring humates like leonardite and brown coal or lignite are marketed under different brand names e.g. Pak Humates, Humate Fertilizer, Pak Humax, Humkara and Humide etc. However, their efficacy is needed to be confirmed before their use. Different studies were conducted for the comparison of four commercial humates for their physico-chemical, optical properties, plant growth promoting ability in terms of seed germination and seedling vigour in wheat (cv Sehr, mung bean (Mung-54, maize (C-12 and sesbania and their effect on growth of some fungi. Moisture content of four humates varied from 0.52 to 71.11%, while solubility in water varied from 30.2 to 98.2% and density differed from 1.67 to 4.17. A 2% solution of humates had pH and EC varying from 5.39 to 10.11 and 3.140 to 1.143 mS cm-1, respectively. Carbon and nitrogen concentrations varied from 22.95 to 36.56% and 0.658 to 1.183, respectively with a C/N ratio of 30.91 to 44.16. Humates dissolved in 0.1N NaOH were partitioned into humic acid and fulvic acid fractions. Of the total C in humates, 40.3 to 77.5% was ranged in humic acid and 22.5 to 59.7% in fulvic acid fraction. The HA was also studied for optical properties at 400, 500, 600, and 700 nm besides that at 465 and 665 to calculate E4/E6 (extinction coefficient; the later varied between 3.64 and 5.48. Optical density of the humic acid decreased at increasing wavelength and was correlated significantly with the carbon contents of humic compounds. Three fungi, Trichoderma harzianum, T. hamatum and Alternaria alternata showed maximum growth at 0.025% HA in the growth medium on the basis of colony diameter. Humates inhibited seed germination in wheat, maize and mung bean except for sesbania. Root length and shoot dry matter increased in wheat and maize but no effect was found in mung bean and sesbania. The studies revealed that humates available in the market vary widely and therefore some sort of quality monitoring is required

  7. Effect of Humic Acid and Phosphorus on the Quantity and Quality of Marigold (Calendula officinalis L. Yield

    Directory of Open Access Journals (Sweden)

    A.A Farjami,

    2014-03-01

    Full Text Available To evaluate the effect of humic acid and phosphorus on the quantity and quality of marigold yield an experiment was conducted at Research Field of Islamic Azad University, Mashhad Branch, Mashhad, Iran, in cropping season 2010-2011. The experiment was in split plot based on randomized complete block design, with four replications. The main plots were humic acid in four levels (0, 5, 10 and 15 kg/ha and sub plots were phosphorus (P2O5 in three levels (40, 60 and 80 kg/ha. The result showed that the highest dry flower yield (158.4 g/m2, flower number (1356 per m2, essential oil (0.55%, active ingredient of flower (0.31%, obtained in humic acid (10 kg/ha and phosphorus (60kg/ha. The results also revalued that highest grain yield (133.8 g/m2 and seed oil (0.41% obtained when (5 kg/ha humic acid and 80kg/ha phosphorus were used. Based on this study, humic acid (10 kg/ha and phosphorus (60kg/ha may result in higher yield.

  8. Effects of humic acids from landfill leachate on plants: An integrated approach using chemical, biochemical and cytogenetic analysis.

    Science.gov (United States)

    Morozesk, Mariana; Bonomo, Marina Marques; Souza, Iara da Costa; Rocha, Lívia Dorsch; Duarte, Ian Drumond; Martins, Ian Oliveira; Dobbss, Leonardo Barros; Carneiro, Maria Tereza Weitzel Dias; Fernandes, Marisa Narciso; Matsumoto, Silvia Tamie

    2017-10-01

    Biological process treatment of landfill leachate produces a significant amount of sludge, characterized by high levels of organic matter from which humic acids are known to activate several enzymes of energy metabolism, stimulating plant growth. This study aimed to characterize humic acids extracted from landfill sludge and assess the effects on plants exposed to different concentrations (0.5, 1, 2 and 4 mM C L -1 ) by chemical and biological analysis, to elucidate the influence of such organic material and minimize potential risks of using sludge in natura. Landfill humic acids showed high carbon and nitrogen levels, which may represent an important source of nutrients for plants. Biochemical analysis demonstrated an increase of enzyme activity, especially H + -ATPase in 2 mM C L -1 landfill humic acid. Additionally, cytogenetic alterations were observed in meristematic and F 1 cells, through nuclear abnormalities and micronuclei. Multivariate statistical analysis provided integration of physical, chemical and biological data. Despite all the nutritional benefits of humic acids and their activation of plant antioxidant systems, the observed biological effects showed concerning levels of mutagenicity. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. [Apply fourier transform infrared spectra coupled with two-dimensional correlation analysis to study the evolution of humic acids during composting].

    Science.gov (United States)

    Bu, Gui-jun; Yu, Jing; Di, Hui-hui; Luo, Shi-jia; Zhou, Da-zhai; Xiao, Qiang

    2015-02-01

    The composition and structure of humic acids formed during composting play an important influence on the quality and mature of compost. In order to explore the composition and evolution mechanism, municipal solid wastes were collected to compost and humic and fulvic acids were obtained from these composted municipal solid wastes. Furthermore, fourier transform infrared spectra and two-dimensional correlation analysis were applied to study the composition and transformation of humic and fulvic acids during composting. The results from fourier transform infrared spectra showed that, the composition of humic acids was complex, and several absorbance peaks were observed at 2917-2924, 2844-2852, 2549, 1662, 1622, 1566, 1454, 1398, 1351, 990-1063, 839 and 711 cm(-1). Compared to humic acids, the composition of fulvci acids was simple, and only three peaks were detected at 1725, 1637 and 990 cm(-1). The appearance of these peaks showed that both humic and fulvic acids comprised the benzene originated from lignin and the polysaccharide. In addition, humic acids comprised a large number of aliphatic and protein which were hardly detected in fulvic acids. Aliphatic, polysaccharide, protein and lignin all were degraded during composting, however, the order of degradation was different between humic and fulvci acids. The result from two-dimensional correlation analysis showed that, organic compounds in humic acids were degraded in the following sequence: aliphatic> protein> polysaccharide and lignin, while that in fulvic acids was as following: protein> polysaccharide and aliphatic. A large number of carboxyl, alcohols and ethers were formed during the degradation process, and the carboxyl was transformed into carbonates. It can be concluded that, fourier transform infrared spectra coupled with two-dimensional correlation analysis not only can analyze the function group composition of humic substances, but also can characterize effectively the degradation sequence of these

  10. Humic Acid Complexation of Th, Hf and Zr in Ligand Competition Experiments: Metal Loading and Ph Effects

    Science.gov (United States)

    Stern, Jennifer C.; Foustoukos, Dionysis I.; Sonke, Jeroen E.; Salters, Vincent J. M.

    2014-01-01

    The mobility of metals in soils and subsurface aquifers is strongly affected by sorption and complexation with dissolved organic matter, oxyhydroxides, clay minerals, and inorganic ligands. Humic substances (HS) are organic macromolecules with functional groups that have a strong affinity for binding metals, such as actinides. Thorium, often studied as an analog for tetravalent actinides, has also been shown to strongly associate with dissolved and colloidal HS in natural waters. The effects of HS on the mobilization dynamics of actinides are of particular interest in risk assessment of nuclear waste repositories. Here, we present conditional equilibrium binding constants (Kc, MHA) of thorium, hafnium, and zirconium-humic acid complexes from ligand competition experiments using capillary electrophoresis coupled with ICP-MS (CE- ICP-MS). Equilibrium dialysis ligand exchange (EDLE) experiments using size exclusion via a 1000 Damembrane were also performed to validate the CE-ICP-MS analysis. Experiments were performed at pH 3.5-7 with solutions containing one tetravalent metal (Th, Hf, or Zr), Elliot soil humic acid (EHA) or Pahokee peat humic acid (PHA), and EDTA. CE-ICP-MS and EDLE experiments yielded nearly identical binding constants for the metal- humic acid complexes, indicating that both methods are appropriate for examining metal speciation at conditions lower than neutral pH. We find that tetravalent metals form strong complexes with humic acids, with Kc, MHA several orders of magnitude above REE-humic complexes. Experiments were conducted at a range of dissolved HA concentrations to examine the effect of [HA]/[Th] molar ratio on Kc, MHA. At low metal loading conditions (i.e. elevated [HA]/[Th] ratios) the ThHA binding constant reached values that were not affected by the relative abundance of humic acid and thorium. The importance of [HA]/[Th] molar ratios on constraining the equilibrium of MHA complexation is apparent when our estimated Kc, MHA values

  11. The effect of the humic acid and herbal additive supplement on production parameters of broiler chicken

    Directory of Open Access Journals (Sweden)

    Veronika Pistová

    2016-10-01

    Full Text Available In this study the effect of humic acids and dietary herbal additive (clove (Syzygium aromaticum, lavender (Lavendula angustifolia and black pepper (Piper nigrum L. on production parameters of broiler chicken were studied.  A total of 60 Ross 308 broiler chicken were divided into 3 treatments (n=20. The control group of chickens was fed with complete feed mixtures without any additives. Chicken in treatment T1 were fed a diet containing 1% of humic acid and drank a water containing 150 mg/l of herbal additive. Chicken in treatment T2 were fed with complete feed mixture without any additives and drank a water containing 150 mg/l of herbal additive. The body weight, feed intake and feed conversion were evaluated. The results shout that the body weight was significantly higher (P≤0.05 in treatments groups compared to the control group (the order of the groups: 1796.4±188.1; 2052.9±197.9 and 2140.4±300.4 g±SD. The feed intake was in the control group 3.11 kg, in the treatment T1 3.00 kg and in the treatment T2 3.12 kg. Feed conversion for the entire fattening period was in control group 2.19 kg/kg complete feed mixture, in the treatment T1 1.83 kg/kg complete feed mixture and in the treatment T2 1.84 kg/kg complete feed mixture with no significant different (P≥0.05 compared to control group. In conclusion, supplement by humic acid and herbal additive can improve production parameters of broiler chicken.

  12. Investigations on humic acid removal from water using surfactant-modified zeolite as adsorbent in a fixed-bed reactor

    Science.gov (United States)

    Elsheikh, Awad F.; Ahmad, Umi Kalthom; Ramli, Zainab

    2017-10-01

    Natural organic matter (NOM) is ubiquitous in aquatic environments and has recently become an issue of worldwide concern in drinking water treatment. The major component of NOM is humic acids (HA). In this study, a natural zeolite (mordenite) was modified employing hexadecyltrimethylammonium bromide (HDTMA) to enhance greater efficient sites for sorption of HA. The natural zeolite and surfactant-modified zeolite (SMZ) were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectrometer (FT-IR), N2 Adsorption-desorption isotherms and BET-specific surface area, thermographic analysis, derivative thermographic analysis (TGA-DTA) and Field emission scanning electron microscopy (FESEM). A fixed-bed reactor was used for the removal of HA and the effects of different experimental parameters such as HDTMA loading levels, HA solution flow rate, solution pH and eluent concentration were investigated. The results indicated that the SMZ bed with HDTMA loading of 75% of external cation exchange capacity (ECEC) at a flow rate of 2 BV/h and pH of 10 showed the greatest enhanced removal efficiency of HA while ethanol solutions (25%v/v) with feed flow rate of 2 BV/h were sufficient for complete regeneration of SMZ and desorption of HA. Measurements of surface area of SMZ indicated that a monolayer formation of the surfactant at those conditions allowed the optimum removal of HA.

  13. Sorption and toxicity reduction of pharmaceutically active compounds and endocrine disrupting chemicals in the presence of colloidal humic acid.

    Science.gov (United States)

    Kim, Injeong; Kim, Hyo-Dong; Jeong, Tae-Yong; Kim, Sang Don

    This study investigated the toxicity changes and sorption of pharmaceuticals and endocrine disrupters in the presence of humic acid (HA). For the sorption experiment, a dead end filtration (DEF) system was used to separate bound and free-form target compounds. An algae growth inhibition test and E-screen assay were conducted to estimate the toxic effect of pharmaceutically active compounds (PhACs) and endocrine disrupting chemicals (EDCs), respectively. The permeate concentration was confirmed using liquid chromatography-mass spectrometry. In the sorption test, we observed significant sorption of PhACs and EDCs on colloidal HA, except for sulfamethoxazole (SMX). The values of log KCOC derived from DEF determinations ranged from 4.40 to 5.03. The removal efficiency varied with the HA concentration and the target chemical properties. Tetracycline and 4-octylphenol showed the highest sorption or removal efficiency (≈50%), even at 5 mg C/L HA. The algal growth inhibition of PhACs and the estrogenic effects of EDCs were significantly decreased in proportion to HA concentrations, except for SMX. In addition, the chemical analysis results showed a positive relationship with the bioassay results. Consequently, the sorption of PhACs and EDCs onto colloidal HA should be emphasized in natural environments because it significantly reduces bioavailable concentrations and toxicity to aquatic organisms.

  14. Influence of humic acid addition on the degradation of pharmaceuticals by biofilms in effluent wastewater

    DEFF Research Database (Denmark)

    Tang, Kai; Escola Casas, Monica; Ooi, Gordon Tze Hoong

    2017-01-01

    in relation to the biodegradation of pharmaceuticals by suspended biofilm carriers adapted to polishing effluent water from a tertiary sewage treatment plant. Twelve out of 22 investigated pharmaceuticals were significantly biodegradable. The biodegradation rate constants of ten of those compounds were......The degradation of organic micropollutants in wastewater treatment is suspected to depend on co-degradation i.e. be dependent on concentrations of substrate. This complicates predicting and modelling their fate. The effect of humic acid, as a model for complex organic substrate, was investigated...

  15. Mobilization of arsenic and heavy metals from polluted soils by humic acid

    Science.gov (United States)

    Reyes, Arturo; Fuentes, Bárbara; Letelier, María Victoria; Cuevas, Jacqueline

    2017-04-01

    The existence of soils contaminated with harmful elements by mining activities is a global environmental concern. The northern part of Chile has several heavy metal contaminated sites due to former copper and gold artisanal mining activities. Therefore, a complete characterization of abandoned sites and the implementation of remediation technologies are of interest for regulators, the industry, and the population. The objective of the study was to test the use of humic acid as a washing treatment to reduce the heavy metal concentration of soil samples impacted by mine waste material. A stratified random sampling was conducted on the target site to determine the physical and chemical composition of mine waste and soil material. The sampling consisted of taking 37 samples at 0-20 cm depths in a 10,000 square-meter area. The samples were dried and sieved at 2 mm. The batch washing experiments were conducted in triplicate at pH 7.0. A 1:10 solid to liquid ratio and three humic acid dose (0, 50, and 100 mg/l) were used. After shaking (24 h, room temperature) and subsequently filtration (0.22 μm), the supernatants were analyzed for heavy metals, redox potential and pH. The heavy metals mobility was assessed using extraction methods before and after treatments. The soils had alkaline pH values, conductivity ranged between 8 and 35 mS/cm, with low organic matter. Total concentrations of Vanadium (V) (10.80 to 175.00 mg/kg), Lead (Pb) (7.31 to 90.10 mg/kg), Antimonium (Sb) (0.83 to 101.00 mg/kg), and Arsenic (As) (9.53 to 2691.00 mg/kg) exceeded several times the EPA`s recommended values for soils. At 100 mg/L HA the removal efficiencies for V, Pb, Sb, and As were 32, 68, 77, and 82% respectively. According to the extraction procedure V, Pb, Sb, and As species are mainly as oxidizable and residual fractions. According to the results, the target mine site is contaminated with harmful elements. It can be concluded that the use of humic acid is a good alternative as a

  16. Nanoparticle-assisted photo-Fenton reaction for photo-decomposition of humic acid

    Science.gov (United States)

    Banik, Jhuma; Basumallick, Srijita

    2017-11-01

    We report here the synthesis of CuO-doped ZnO composite nanomaterials (NMs) by chemical route and demonstrated for the first time that these NMs are efficient catalysts for H2O2-assisted photo-decomposition (photo-Fenton type catalyst) of humic acid, a natural pollutant of surface water by solar irradiation. This has been explained by faster electron transfer to OH radical at the p-n hetero-junction of this composite catalyst. Application of this composite catalyst in decomposing humus substances of local pond water by solar energy has been demonstrated.

  17. BORON CONCENTRATION IN HUMIC AND FULVIC ACID EXTRACTS OF SOIL EPIPEDON IN SAN VITALE PINEWOOD (RAVENNA, ITALY

    Directory of Open Access Journals (Sweden)

    Maddalena Pennisi

    2010-08-01

    Full Text Available Humified Soil Organic Matter (SOM plays a crucial role in the assessment of soil quality since it makes up a significant part of the total organic carbon and nitrogen in soils. High concentrations of humic and fulvic acids may be presents in soils and subordinately in sediments. These substances can potentially act as a significant reservoir of adsorbed boron as well as a source of this element to soil solution, rivers, and lakes. The aim of this study was to investigate boron in humic substances (e.g. humic and fulvic acids of soil epipedon. The San Vitale pinewood was selected as the study site and three samples - classified as Sodic Psammaquents and Typic Psammaquants - of the A1-horizon epipedon were analyzed for humic and fulvic acids and boron contents. The knowledge of the mechanisms of boron interaction with SOM is important for a better understanding of the water/rock interaction in the superficial soil environment, and to envisage the application of the blending of boron into humic acid granules in agricultural practices.

  18. SOLUBILIZATION OF POTASSIUM FROM ALTERNATIVE ROCKS BY HUMIC AND CITRIC ACIDS AND COFFEE HUSK

    Directory of Open Access Journals (Sweden)

    Rodrigo Souza Pessoa

    2015-12-01

    Full Text Available ABSTRACT Brazil imports most of the potassium that it consumes in agriculture, however, such huge external dependence can be minimized with the use of alternative local K bearing rocks. This experiment was conducted with the objective of evaluating the solubility of nepheline syenite and glauconite as a function of three organic matrices, humic acid, citric acid and coffee husk. Incubation of low grade K rocks and organic matrices were done in laboratory conditions, in a completely randomized design. Each rock was mixed with five different doses of each organic matrix and the potassium solubilized was measured periodically, during 180 days. Regardless of the organic matrix and its dose investigated, nepheline syenite samples released more K than the modified glauconite. Soluble K increased as the incubation time increased and its release was greater as the organic matrix dose increased. There was more soluble K when the coffee husk was mixed with the potassic rocks, in relation to the humic and citric acids.

  19. Study of stability of humic acids from soil and peat irradiated by gamma rays

    International Nuclear Information System (INIS)

    Silva, Wilson Tadeu Lopes da

    1995-01-01

    Humic acids samples (one deriving from a sedimentary soil and other from a peat), in aqueous media, were irradiated with gamma rays, in doses of 10, 50 and 100 kGy, in order to understand their chemical behavior after the irradiation. The material, before and after irradiation, was analyzed by Elemental Analysis, Functional Groups (carboxylic acids and phenols), UV/Vis Spectroscopy (E 4 /E 6 ratio), IR spectroscopy, CO 2 content and Gel permeation Chromatography (GPC) ). The Elemental Analysis showed the humic acid derived from a peat had a most percentage quantity of Carbon and Hydrogen than the material from a sedimentary soil. From the UV/Vis Spectroscopy, it was observed a decrease of E 4 /E 6 ratio with an increase of the applied dose. The data from GPC are in agreement with this. The results showed that the molecular weight of the material increased by exposing it to a larger radiolitical dose. The peat material was less affected by the gamma radiation than the soil material. The carboxylic groups were responsible by radiochemical behavior of the material. (author)

  20. [The investigation of humic acid by surface-enhanced Raman spectroscopy].

    Science.gov (United States)

    Zhang, Wen-Juan; Li, Ying; Guo, Jin-Jia; Xiao, Qiong; Yu, Li

    2013-05-01

    Humic acid (HA), which are organic compounds widely existing in the oceans, rivers and soil, has important significance for the environmental monitoring of soil and water. In this paper, ai ming at the problem of Surface-enhanced Raman Spectroscopy (SERS) applying for HA detection in water, the characteristics of the humic acid on silver colloids was studied by means of SERS. The influence of laser irradiation time, HA concentrations and pH value on the surface-enhanced effects of HA were investigated. The experimental results show that the SERS spectra of HA is ideal when the laser irradiation time between 20-30 min. The SERS of different HA concentrations was detected. It was found that the relative intensity at 1 379 cm(-1) increased as a linear function of the concentration of HA with correlation coefficient R2 of 0.993. The SERS of HA was found to be very sensitive to pH, the SERS spectra of HA was very weak at neutral pH, but at acidic pH and alkaline pH a remarkable increase of SERS intensity occurred. The SERS of HA in running water was detected too. The experimental results show that it is feasible to detect HA in natural water by means of surface-enhanced Raman spectroscopy.

  1. The effect of humic acid on uranyl sorption onto bentonite at trace uranium levels.

    Science.gov (United States)

    Ivanov, Peter; Griffiths, Tamara; Bryan, Nick D; Bozhikov, Gospodin; Dmitriev, Serguei

    2012-11-01

    The effect of humic acid (HA) on U(VI) sorption on bentonite was studied in batch experiments at room temperature and ambient atmosphere at a (237)U(VI) concentration of 8.4 × 10(-11) M and HA concentration of 100 mg L(-1). The distribution of U(VI) between the liquid and solid phases was studied as a function of pH and ionic strength both in the absence and presence of HA. It was shown that the uranyl sorption on bentonite is strongly dependent on pH and the presence of humics, and the effect of the addition order was negligible. In the absence of HA an enhancement in the uptake with increasing pH was observed and a sharp sorption edge was found to take place between pH 3.2 and 4.2. The presence of HA slightly increases uranium(VI) sorption at low pH and curtails it at moderate pH, compared to the absence of HA. In the basic pH range for both the presence and absence of HA the sorption of uranium is significantly reduced, which could be attributed to the formation of soluble uranyl carbonate complexes. The influence of ionic strength on U(VI) and HA uptake by bentonite were investigated in the range of 0.01-1.0 M, and while there was an enhancement in the sorption of humic acid with increasing ionic strength, no significant effect of the ionic strength on the U(VI) sorption was observed in both the absence and presence of HA.

  2. Effect of Humic Acids and pesticides on Agricultural Soil Structure and Stability and Its Implication on Soil Quality

    Science.gov (United States)

    Gaonkar, O. D.; Nambi, I. M.; G, S. K.

    2016-12-01

    The functional and morphological aspects of soil structure determine the soil quality. The dispersion of colloidal soil particles, especially the clay fraction and rupture of soil aggregates, both of which play an important role in soil structure development, lead to degradation of soil quality. The main objective of this work was to determine the effect of behaviour of soil colloids on the agricultural soil structure and quality. The effect of commercial humic acid, organophosphate pesticides and soil natural organic matter on the electrical and structural properties of the soil colloids was also studied. Agricultural soil, belonging to the sandy loam texture class from northern part of India was considered in this study. In order to understand the changes in the soil quality in the presence and absence of humic acids, the soil fabric and structure was analyzed by X-ray diffraction (XRD), Fourier Transform Infrared (FTIR) Spectroscopy and Scanning Electron Microscopy (SEM). Electrical properties of natural soil colloids in aqueous suspensions were assessed by zeta potential measurements at varying pH values with and without the presence of humic acids and pesticides. The influence of natural organic matter was analyzed by oxidizing the natural soil organic matter with hydrogen peroxide. The zeta potential of the soil colloids was found to be negative in the pH range studied. The results indicated that hydrogen peroxide treatment lead to deflocculation of colloidal soil particles. In addition, the humic acids undergoes effective adsorption onto the soil surface imparting more negative zeta potential to the colloidal soil particles. The soil hydrophilicity decreased in the presence of humic acids which was confirmed by surface free energy determination. Thus, it can be concluded that the presence of humic acids altered the soil fabric and structure, thereby affecting the soil quality. This study assumes significance in understanding the soil aggregation and the

  3. Origin and structures of groundwater humic substances from three Danish aquifers

    DEFF Research Database (Denmark)

    Grøn, C.; Wassenaar, L.; Krog, M.

    1996-01-01

    and halogens, hydrolyzable amino acids and carbohydrates, carbon isotopes) applied to aquatic humic and fulvic acids led to consistent structural interpretations for each of the three aquifers studied. For humic substances in two-aquifers, the analyses suggested source rocks in agreement with geological...... and hydrogeochemical information. In a third aquifer, source rock identification was inconclusive, and multiple fossil and recent organic carbon sources are suggested....

  4. Effect of humic acid on water chemistry, bioavailability and toxicity of aluminium in the freshwater snail, Lymnaea stagnalis, at neutral pH

    Energy Technology Data Exchange (ETDEWEB)

    Dobranskyte, A. [Faculty of Life Sciences, University of Manchester, Oxford Road, Manchester M13 9PT (United Kingdom); Jugdaohsingh, R. [Gastrointestinal Laboratory, Rayne Institute, St Thomas' Hospital, London SE1 7EH (United Kingdom); McCrohan, C.R. [Faculty of Life Sciences, University of Manchester, Oxford Road, Manchester M13 9PT (United Kingdom); Stuchlik, E. [Hydrobiological Station, Institute for Environmental Studies, Charles University, Prague (Czech Republic); Powell, J.J. [MRC Human Nutrition Research, Elsie Widdowson Laboratory, Fulbourn Road, Cambridge CB1 9NL (United Kingdom); White, K.N. [Faculty of Life Sciences, University of Manchester, Oxford Road, Manchester M13 9PT (United Kingdom)]. E-mail: keith.white@manchester.ac.uk

    2006-03-15

    The influence of humic acid on the water chemistry of environmentally relevant concentrations of Al at neutral pH was studied, together with its effect on the bioavailability and toxicity of Al in Lymnaea stagnalis. Humic acid significantly reduced the loss of Al from the water and increased the fraction of filterable Al, although this was a relatively small fraction of total Al. Filterable Al concentration in the presence or absence of humic acid was independent of initial Al concentration. Humic acid only partly reduced toxicity, as observed by a reduction in behavioural suppression, and had no effect on the level of Al accumulated in tissues. These results suggest that humic acid maintains Al in a colloidal form that is bioavailable to L. stagnalis. However, these colloidal Al-humic acid species were less toxic since behavioural toxicity was reduced. Humic acid may play an important role in limiting the toxicity of Al to freshwater organisms. - Humic acid reduces aluminium toxicity in freshwater snails.

  5. Investigating organic molecules responsible of auxin-like activity of humic acid fraction extracted from vermicompost

    International Nuclear Information System (INIS)

    Scaglia, Barbara; Nunes, Ramom Rachide; Rezende, Maria Olímpia Oliveira; Tambone, Fulvia; Adani, Fabrizio

    2016-01-01

    This work studied the auxin-like activity of humic acids (HA) obtained from vermicomposts produced using leather wastes plus cattle dung at different maturation stages (fresh, stable and mature). Bioassays were performed by testing HA concentrations in the range of 100–6000 mg carbon L −1 . 13 C CPMAS-NMR and GC–MS instrumental methods were used to assess the effect of biological processes and starting organic mixtures on HA composition. Not all HAs showed IAA-like activity and in general, IAA-like activity increased with the length of the vermicomposting process. The presence of leather wastes was not necessary to produce the auxin-like activity of HA, since HA extracted from a mix of cattle manure and sawdust, where no leather waste was added, showed IAA-like activity as well. CPMAS 13 CNMR revealed that HAs were similar independently of the mix used and that the humification process involved the increasing concentration of pre-existing alkali soluble fractions in the biomass. GC/MS allowed the identification of the molecules involved in IAA-like effects: carboxylic acids and amino acids. The concentration of active molecules, rather than their simple presence in HA, determined the bio-stimulating effect, and a good linear regression between auxin-like activity and active stimulating molecules concentration was found (R 2 = − 0.85; p < 0.01, n = 6). - Highlights: • Vermicomposting converts waste into organic fertilizer. • Vermicomposts can have biostimulating effect for the presence of hormone-like molecules. • Auxine-like activity was associated to the vermicompost humic acid fraction (HA). • HA carboxylic acids and amino acids, were reported to act as auxin-like molecules. • A linear regression was found between molecules and auxin-like activity.

  6. Investigating organic molecules responsible of auxin-like activity of humic acid fraction extracted from vermicompost

    Energy Technology Data Exchange (ETDEWEB)

    Scaglia, Barbara, E-mail: barbara.scaglia@unimi.it [Gruppo Ricicla Labs – DiSAA, Università degli Studi di Milano, Via Celoria 2 (Italy); Nunes, Ramom Rachide; Rezende, Maria Olímpia Oliveira [Laboratório de Química Ambiental, Universidade de São Paulo, Instituto de Química de São Carlos, Avenida Trabalhador São Carlense, 400, São Carlos (Brazil); Tambone, Fulvia [Gruppo Ricicla Labs – DiSAA, Università degli Studi di Milano, Via Celoria 2 (Italy); Adani, Fabrizio, E-mail: fabrizio.adani@unimi.it [Gruppo Ricicla Labs – DiSAA, Università degli Studi di Milano, Via Celoria 2 (Italy)

    2016-08-15

    This work studied the auxin-like activity of humic acids (HA) obtained from vermicomposts produced using leather wastes plus cattle dung at different maturation stages (fresh, stable and mature). Bioassays were performed by testing HA concentrations in the range of 100–6000 mg carbon L{sup −1}. {sup 13}C CPMAS-NMR and GC–MS instrumental methods were used to assess the effect of biological processes and starting organic mixtures on HA composition. Not all HAs showed IAA-like activity and in general, IAA-like activity increased with the length of the vermicomposting process. The presence of leather wastes was not necessary to produce the auxin-like activity of HA, since HA extracted from a mix of cattle manure and sawdust, where no leather waste was added, showed IAA-like activity as well. CPMAS {sup 13}CNMR revealed that HAs were similar independently of the mix used and that the humification process involved the increasing concentration of pre-existing alkali soluble fractions in the biomass. GC/MS allowed the identification of the molecules involved in IAA-like effects: carboxylic acids and amino acids. The concentration of active molecules, rather than their simple presence in HA, determined the bio-stimulating effect, and a good linear regression between auxin-like activity and active stimulating molecules concentration was found (R{sup 2} = − 0.85; p < 0.01, n = 6). - Highlights: • Vermicomposting converts waste into organic fertilizer. • Vermicomposts can have biostimulating effect for the presence of hormone-like molecules. • Auxine-like activity was associated to the vermicompost humic acid fraction (HA). • HA carboxylic acids and amino acids, were reported to act as auxin-like molecules. • A linear regression was found between molecules and auxin-like activity.

  7. Effects of humic acid on the interactions between zinc oxide nanoparticles and bacterial biofilms.

    Science.gov (United States)

    Ouyang, Kai; Yu, Xiao-Ying; Zhu, Yunlin; Gao, Chunhui; Huang, Qiaoyun; Cai, Peng

    2017-12-01

    The effects of humic acid (HA) on interactions between ZnO nanoparticles (ZnO NPs) and Pseudomonas putida KT2440 biofilms at different maturity stages were investigated. Three stages of biofilm development were identified according to bacterial adenosine triphosphate (ATP) activity associated with biofilm development process. In the initial biofilm stage 1, the ATP content of bacteria was reduced by more than 90% when biofilms were exposed to ZnO NPs. However, in the mature biofilm stages 2 and 3, the ATP content was only slightly decreased. Biofilms at stage 3 exhibited less susceptibility to ZnO NPs than biofilms at stage 2. These results suggest that more mature biofilms have a significantly higher tolerance to ZnO NPs compared to young biofilms. In addition, biofilms with intact extracellular polymeric substances (EPS) showed higher tolerance to ZnO NPs than those without EPS, indicating that EPS play a key role in alleviating the toxic effects of ZnO NPs. In both pure ZnO NPs and ZnO-HA mixtures, dissolved Zn 2+ originating from the NPs significantly contributed to the overall toxicity. The presence of HA dramatically decreased the toxicity of ZnO NPs due to the binding of Zn 2+ on HA. The combined results from this work suggest that the biofilm maturity stages and environmental constituents (such as humic acid) are important factors to consider when evaluating potential risks of NPs to ecological systems. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. A comparative chemical-structural study of fossil humic acids and those extracted from urban wastes

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, C.; Hernandez, T.; Costa, F.; Ceccanti, B.; Polo, A. (Centro de Edafologia y Biologia Aplicada del Segura, Murcia (Spain))

    1992-05-01

    Chemical-structural features of commercial humic acids (HAs) from leonardite or lignite were studied and the data obtained were compared with those of humic acids extracted from composted urban wastes. The greatest differences showed by the elemental analysis between the three HAs were in N and H contents, both of which diminished with the oxidation degree of the starting materials. FTIR spectra did not show differences between HAs from evolved materials such as leonardite or lignite. However, differences were found between these HAs and those extracted from composts of urban wastes, which showed a greater aliphatic character and a more pronounced peak in the absorption band attributed to secondary amides and in that of carbohydrates. The {sup 13}C-NMR spectra were similar for both HAs from leonardite regardless of their oxidation degree. The percentage of aromaticity of these HAs was 45%. The spectra of compost HAs showed a low aromaticity degree for these HAs as a consequence of the pronounced peak appearing at 73 ppm corresponding to carbon of carbohydrates and/or polyalcohols and aminoacids. Py-GC revealed a high content of benzene and toluene in all the commercial HAs. The values of these fragments as well as those of the ratios between pyrolitic fragments, used as humification index for soils, were the highest in the HA extracted from the more oxidized leonardite. 17 refs., 1 fig., 5 tabs.

  9. Hybrid Processes Combining Photocatalysis and Ceramic Membrane Filtration for Degradation of Humic Acids in Saline Water

    Science.gov (United States)

    Song, Lili; Zhu, Bo; Gray, Stephen; Duke, Mikel; Muthukumaran, Shobha

    2016-01-01

    This study explored the combined effects of photocatalysis with ceramic membrane filtration for the removal of humic acid in the presence of salt; to simulate saline wastewater conditions. The effects of operating parameters, such as salinity and TiO2 concentration on permeate fluxes, total organic carbon (TOC), and UV absorbance removal, were investigated. The interaction between the humic acids and TiO2 photocatalyst played an important role in the observed flux change during ceramic membrane filtration. The results for this hybrid system showed that the TOC removal was more than 70% for both without NaCl and with the 500 ppm NaCl concentration, and 62% and 66% for 1000 and 2000 ppm NaCl concentrations. The reduction in UV absorbance was more complete in the absence of NaCl compared to the presence of NaCl. The operation of the integrated photoreactor-ceramic membrane filter over five repeat cycles is described. It can be concluded that the overall removal performance of the hybrid system was influenced by the presence of salts, as salt leads to agglomeration of TiO2 particles by suppressing the stabilising effects of electrostatic repulsion and thereby reduces the effective surface contact between the pollutant and the photocatalyst. PMID:26938568

  10. Hybrid Processes Combining Photocatalysis and Ceramic Membrane Filtration for Degradation of Humic Acids in Saline Water

    Directory of Open Access Journals (Sweden)

    Lili Song

    2016-03-01

    Full Text Available This study explored the combined effects of photocatalysis with ceramic membrane filtration for the removal of humic acid in the presence of salt; to simulate saline wastewater conditions. The effects of operating parameters, such as salinity and TiO2 concentration on permeate fluxes, total organic carbon (TOC, and UV absorbance removal, were investigated. The interaction between the humic acids and TiO2 photocatalyst played an important role in the observed flux change during ceramic membrane filtration. The results for this hybrid system showed that the TOC removal was more than 70% for both without NaCl and with the 500 ppm NaCl concentration, and 62% and 66% for 1000 and 2000 ppm NaCl concentrations. The reduction in UV absorbance was more complete in the absence of NaCl compared to the presence of NaCl. The operation of the integrated photoreactor-ceramic membrane filter over five repeat cycles is described. It can be concluded that the overall removal performance of the hybrid system was influenced by the presence of salts, as salt leads to agglomeration of TiO2 particles by suppressing the stabilising effects of electrostatic repulsion and thereby reduces the effective surface contact between the pollutant and the photocatalyst.

  11. The Infrared Spectrum Analysis on Compound Urea with Humic Acid Extracted from Weathered Coal

    Directory of Open Access Journals (Sweden)

    LIU Zeng-bing

    2014-10-01

    Full Text Available After treated with alkaline solution and then centrifuged, weathered coal was divided into water-soluble humic acid and deposi- tion. Then as the urea synergist materials, weathering coal, humic acid and deposition were respectively mixed with melted urea according to different proportion to produce three kinds of compound urea. The infrared spectrum analysis(IRof above synergist materials and products found that after being treated with alkaline, weathered coal was reduced carbon-carbon bond amount and its carbon chain became shorten,more active functional group happened to the HA extracts. While the FR deposition showed carbon-carbon bond reduced and parts of amine or amide structure were formed. Additionally, the IR also found that during the compound of urea with the synergists, the formation of carbon-carbon triple bond, the broken of accumulated double bonds, the shorten of carbon chain, and the formation of more double bond and stablestructure were observed. However, the different synergists mixed with urea brought out different IR characters.

  12. Binding of polycyclic aromatic hydrocarbons by humic acids formed during composting

    International Nuclear Information System (INIS)

    Plaza, Cesar; Xing Baoshan; Fernandez, Jose M.; Senesi, Nicola; Polo, Alfredo

    2009-01-01

    Binding of two model polycyclic aromatic hydrocarbons (PAHs), phenanthrene and pyrene, by humic acids (HAs) isolated from an organic substrate at different stages of composting and a soil was investigated using a batch fluorescence quenching method and the modified Freundlich model. With respect to soil HA, the organic substrate HA fractions were characterized by larger binding affinities for both phenanthrene and pyrene. Further, isotherm deviation from linearity was larger for soil HA than for organic substrate HAs, indicating a larger heterogeneity of binding sites in the former. The composting process decreased the binding affinity and increased the heterogeneity of binding sites of HAs. The changes undergone by the HA fraction during composting may be expected to contribute to facilitate microbial accessibility to PAHs. The results obtained also suggest that bioremediation of PAH-contaminated soils with matured compost, rather than with fresh organic amendments, may result in faster and more effective cleanup. - Composting of organic materials decreases the binding affinity of the humic acid fraction for polycyclic aromatic hydrocarbons

  13. Effects of supplemental humic acid on ruminal fermentation and blood variables in rams

    Directory of Open Access Journals (Sweden)

    Nurten Galip

    Full Text Available In this study, we particularly aimed to research the effect of supplemental humic acid on ruminal fermentation and blood variables in rams. A trial was conducted to evaluate the effect of humic acid (HA on protozoa count, percentages of different protozoa types and blood parameters. Three male Kivircik rams with ruminal cannula were used in a Latin square design, during 22 days periods (15 days for adaptation, 7 days for collection. They received 0 control group (CG, 5 g/day or 10 g/day of HA (HA5, HA10, assay groups. HA were added to the ration with grain diet. Ration was consisted of 5% grain diet and 95 % alfalfa hay. Rumen contents collected before, 3h and 6h after morning feeding on days 1 and 7 in each collection period were analyzed. Blood samples were also collected the same days. No significant difference in biochemical and hematological parameters (except eosinophils levels, P<0.05, variables of ruminal fluid (except sodium levels before feeding and species of rumen protozoa organism (except the percentage Epidinium spp. were evidenced with the addition of HA. In conclusion, we think that they might have been true the widely use in animal food of humates which don’t have any negative effect on biochemical and hematological parameters in particular.

  14. Using Spectrophotometric Titrations To Characterize Humic Acid Reactivity at Environmental Concentrations

    International Nuclear Information System (INIS)

    Janot, N.; Benedetti, M. F.; Janot, N.; Reiller, P. E.; Korshin, G. V.

    2010-01-01

    Potentiometric titration is a common method to characterize dissolved organic matter (DOM) reactivity. Because of the sensitivity of pH electrodes, it is necessary to work with very high DOM (≥1 g/L) concentrations that are unrealistic compared to those found in natural waters (0. 1 to 100 mg/L). To obtain proton binding data for concentrations closer to environmental values, spectroscopic titration methodology is a viable alternative to traditional potentiometric titrations. Spectrophotometric titrations and UV visible spectra of a diluted solution of purified Aldrich humic acid (5 mg(DOC)/L) are used to estimate changes in proton binding moieties as function of pH and ionic strength after calculation of differential absorbance spectra variations. After electrostatic correction of spectrophotometric data, there is a linear operational correlation between spectrophotometric and potentiometric data which can be used as a transfer function between the two properties. Spectrophotometric titrations are then used to determine the changes of humic acid protonation after adsorption onto alpha-alumina. (authors)

  15. Effects of supplemental humic acid on ruminal fermentation and blood variables in rams

    Directory of Open Access Journals (Sweden)

    Umit Polat

    2010-11-01

    Full Text Available In this study, we particularly aimed to research the effect of supplemental humic acid on ruminal fermentation and blood variables in rams. A trial was conducted to evaluate the effect of humic acid (HA on protozoa count, percentages of different protozoa types and blood parameters. Three male Kivircik rams with ruminal cannula were used in a Latin square design, during 22 days periods (15 days for adaptation, 7 days for collection. They received 0 control group (CG, 5 g/day or 10 g/day of HA (HA5, HA10, assay groups. HA were added to the ration with grain diet. Ration was consisted of 5 % grain diet and 95 % alfalfa hay. Rumen contents collected before and, 3h and 6h after morning feeding on days 1 and 7 in each collection period were analyzed. Blood samples were also collected the same days. No significant difference in biochemical and hematological parameters (except eosinophils levels, P, variables of ruminal fluid (except sodium levels before feeding and species of rumen protozoa organism (except the percentage Epidinium spp. were evidenced with the addition of HA. In conclusion, we think that they might have been true the widely use in animal food of humates which don’t have any negative effect on biochemical and hematological parameters in particular. 

  16. Multi-walled carbon nanotube dispersion by the adsorbed humic acids with different chemical structures.

    Science.gov (United States)

    Zhang, Di; Pan, Bo; Cook, Robert L; Xing, Baoshan

    2015-01-01

    Dissolved humic acid (disHA) is effective for suspending carbon nanotubes (CNTs), but the suspending mechanism is still unclear. This study used bleached and hydrolyzed humic acids as suspending agents to investigate effects of chemical structures on CNTs suspension. The adsorption of aromatic moieties enriched disHA to CNTs was lower than aliphatic components-enriched disHA, but the former was better at suspending CNTs. These findings led to the development of a model, in which disHA with aromatic structures results in stable suspension of CNTs due to stronger steric hindrance. Because of their flexible structures, aliphatic components-enriched disHA molecules easily conformed to CNTs leading to higher adsorption to CNTs but weaker steric hindrance between CNTs. Therefore, the bridging and less suspension of CNTs was observed. This study emphasizes that suspending CNTs by disHA is not only controlled by the adsorbed amount of disHA, but also the chemical nature of disHA.

  17. The Effects of Drought Stress and Humic Acid on Morphological Traits, Yield and Anthocyanin of Roselle (Hibiscus sabdariffa L.

    Directory of Open Access Journals (Sweden)

    mojgan sanjarimijani

    2017-01-01

    Full Text Available Introduction Roselle (Hibiscus sabdariffa L. as a medicinal plant belongs to the Malvacea family. Their active ingredient increases under water stress. Humic acid bacteria derived from humus and other natural resources have hormonal effects and can improve nutrient absorption to enhance performance especially under stress conditions . Materials and methods This experiment was conducted in the research of agricultural education centre Jiroft in 2013. Field experiment was carried out as split plot design with three replications. Water deficit stress set as main factor with three levels (A1= Irrigation after 50, A2= 100 and A3= 150 mm evaporation from pan class A and humic acid was in four manners (B1= non humic acid, B2= once with Irrigation, B3= once with Irrigation + Once spraying, B4= once with Irrigation + twice Spraying. Humic acid was used to form Irrigation spray in order to arrange with compactness (10 kg.ha-1, (250 ml/100L. In late September, which coincides with the end of the heading, plant height, inflorescence length, number of branches, stem diameter, fresh and dry weight of plant, fresh and dry weight of sepals, were examined. Wagner method was used to measure anthocyanin content sepals (Wagner, 1979. Finally, data was analyzed using SAS 9.1 and means were compared by Duncan’s multiple range test at 5% level of probability. Results and discussion The analysis of variance showed that drought stress and humic acid had significant effect on growth parameters, vegetative and generative yield and anthocyanin. Drought stress decreased plant height, inflorescence length, stem diameterand fresh and dry weight sepals. The highest values of these traits was obtained in the first level of stress (50 mm evaporation from pan class A. Due to the reduction in mentioned properties, reducing the pressure tolerance and the subsequent reduction in drought conditions was considered as division and cell enlargement. The reduction in growth parameters

  18. The Effects of Drought Stress and Humic Acid on Morphological Traits, Yield and Anthocyanin of Roselle (Hibiscus sabdariffa L.

    Directory of Open Access Journals (Sweden)

    mojgan sanjarimijani

    2017-08-01

    Full Text Available Introduction Roselle (Hibiscus sabdariffa L. as a medicinal plant belongs to the Malvacea family. Their active ingredient increases under water stress. Humic acid bacteria derived from humus and other natural resources have hormonal effects and can improve nutrient absorption to enhance performance especially under stress conditions . Materials and methods This experiment was conducted in the research of agricultural education centre Jiroft in 2013. Field experiment was carried out as split plot design with three replications. Water deficit stress set as main factor with three levels (A1= Irrigation after 50, A2= 100 and A3= 150 mm evaporation from pan class A and humic acid was in four manners (B1= non humic acid, B2= once with Irrigation, B3= once with Irrigation + Once spraying, B4= once with Irrigation + twice Spraying. Humic acid was used to form Irrigation spray in order to arrange with compactness (10 kg.ha-1, (250 ml/100L. In late September, which coincides with the end of the heading, plant height, inflorescence length, number of branches, stem diameter, fresh and dry weight of plant, fresh and dry weight of sepals, were examined. Wagner method was used to measure anthocyanin content sepals (Wagner, 1979. Finally, data was analyzed using SAS 9.1 and means were compared by Duncan’s multiple range test at 5% level of probability. Results and discussion The analysis of variance showed that drought stress and humic acid had significant effect on growth parameters, vegetative and generative yield and anthocyanin. Drought stress decreased plant height, inflorescence length, stem diameterand fresh and dry weight sepals. The highest values of these traits was obtained in the first level of stress (50 mm evaporation from pan class A. Due to the reduction in mentioned properties, reducing the pressure tolerance and the subsequent reduction in drought conditions was considered as division and cell enlargement. The reduction in growth parameters

  19. Effect of humic acids on the growth and the biochemical composition of Arthrospira platensis

    Directory of Open Access Journals (Sweden)

    Massiel Vanessa Rivera Gonzalez

    2017-01-01

    Full Text Available The purpose of this research was to evaluate the effect of three concentrations of humic acids (HA 1, 10, 100 mg/L against a concentration of indole acetic acid (IAA on production of biomass, pigments, proteins, carbohydrates and lipids of A. platensis.  Cultures discontinuous in Zarrouk 25% medium supplemented with HA and IAA under conditions of aeration constant and photoperiod from 12:12 hours, during 30 days were made. It was found that the maximum biomass production was higher in the culture supplemented with 10 mg / L of AH, compared to the control and cultures supplemented with AIA. In the same way the highest production of pigments, proteins and carbohydrates were observed in this treatment. Therefore, the growth and production of metabolites of A. platensis was increased, which makes it possible to observe the potential use of these substances as organic biological stimulants.

  20. An investigation of inorganic antimony species and antimony associated with soil humic acid molar mass fractions in contaminated soils

    International Nuclear Information System (INIS)

    Steely, Sarah; Amarasiriwardena, Dulasiri; Xing Baoshan

    2007-01-01

    The presence of antimony compounds is often suspected in the soil of apple orchards contaminated with lead arsenate pesticide and in the soil of shooting ranges. Nitric acid (1 M) extractable Sb from the shooting range (8300 μg kg -1 ) and the apple orchard (69 μg kg -1 ) had considerably higher surface Sb levels than the control site ( -1 ), and Sb was confined to the top ∼30 cm soil layer. Sb(V) was the principal species in the shooting range and the apple orchard surface soils. Size exclusion chromatography-inductively coupled plasma-mass spectrometry (SEC-ICP-MS) analysis of humic acids isolated from the two contaminated soils demonstrated that Sb has complexed to humic acid molar mass fractions. The results also indicate that humic acids have the ability to arrest the mobility of Sb through soils and would be beneficial in converting Sb(III) to a less toxic species, Sb(V), in contaminated areas. - The soil surface and depth distribution Sb(V) and Sb(III) species in a contaminated apple orchard and a shooting range, and the effect soil humic acids on inorganic antimony species is reported

  1. The role of calcium ions in the photocatalytic oxidation of humic acid at neutral pH.

    Science.gov (United States)

    Mariquit, Eden G; Salim, Chris; Hinode, Hirofumi

    2008-10-01

    Humic acids (HAs) are natural organic matter derived from the decomposition of plant, algal, and microbial materials. They belong to the group of the most predominant type of natural organic matter present in ground and surface waters. HAs affect the mobility and bioavailability of aquatic contaminants. However, if they are left unremoved from the water before water treatment processes, they can form carcinogenic disinfection by-products, such as trihalomethanes, haloacetic acids, and other halogenated disinfection by-products, that can pose a threat to human beings. An advanced oxidation process using UV light and a commercially available titanium dioxide was used to oxidize HA at a pH that is similar to that of natural water. The effect of adding calcium ions to the adsorption and the photocatalytic oxidation of HAs was studied. The effect of varying the TiO(2) load was also investigated. The experiment was done using a photochemical batch reactor equipped with a mercury lamp emitting light with wavelengths of 310-580 nm. The absorbances by the samples were determined at wavelengths of 254 nm and 436 nm, which represent the aromatic-compound content of and the color of the solution, respectively. Results indicated calcium ions have an effect on both the adsorption and the photocatalytic oxidation of HA at a pH within 8.0 +/- 0.5. Calcium ions facilitated adsorption of HA onto the surface of TiO(2) and resulted to faster photocatalytic oxidation. The data were plotted with respect to the normalized absorbances and irradiation time.

  2. Potential risk of coupling products between tetrahalobisphenol A and humic acid prepared via oxidation with a biomimetic catalyst.

    Science.gov (United States)

    Kodama, Ritsu; Sazawa, Kazuto; Miyamoto, Takafumi; Zhu, Qianqian; Igarashi, Mami; Oda, Kohki; Kuramitz, Hideki; Fukushima, Masami

    2018-04-04

    Tetrahalobisphenol A (TXPBAs, X = Br or Cl), TBBPA and TCBPA, which are widely used as flame retardants, ultimately disposed of in landfills. In landfills, enzymatically oxidized TXBPAs can be covalently incorporated into humic acids (HAs) to form coupling products (HA-TXBPAs). In the present study, HA-TXBPAs were prepared by catalytic oxidation with iron(III)-phthalocyanine-tetrasulfate as a model of oxidative enzymes. The stability of HA-TXBPAs was evaluated by incubating them under physicochemical conditions of landfills (pH 9 and 50 °C). For HA-TBBPA, 18-26% of TBBPA was released from HA-TBBPA, due to the acid dissociation of the loosely bound TBBPA. However, no additional release was observed, even after 30 days, indicating that 74-82% of the TBBPA was incorporated into the HA. For HA-TCBPA, 3-4% of TCBPA and a major byproduct, 4-(2-hydroxyisopropyl)-2,6-dichlorophenol, was found to be loosely incorporated into HA. For both TBBPA and TCBPA, covalently bound organo-halogens were not released during the 30 days of incubation. Inhibition of the growth of Chlamydomonas reinhardtii was indicated when trace levels of TXBPAs (approximately 0.1 μM) were present. These results suggest that HA-TXBPAs contain not only covalently incorporated TXBPAs but also loosely bound TXBPAs and halophenols. The latter in HA-TXBPAs have the potential to leach from landfills and affect aquatic ecosystems. Copyright © 2018 Elsevier Ltd. All rights reserved.

  3. Gladiolus development in response to bulb treatment with different concentrations of humic acids

    Directory of Open Access Journals (Sweden)

    Marihus Altoé Baldotto

    2013-02-01

    Full Text Available Gladiolus is an ornamental species produced for cut flowers and propagated by corms. The early flowering and increase in the number of flower buds, besides the production of commercial corms are constant challenges to be addressed in the crop improvement. Commercial production of ornamentals is technologically accelerated by means of growth regulators. Among them, the auxins stand out for their key role in the adventitious rooting and cell elongation. Alternatively, the humic substances present in the organic matter also have biostimulating effect, which is very similar to the auxinic effect. Therefore, this work aimed to study the growth and development of gladiolus in response to application of different concentrations of humic acids (HA isolated from vermicompost. Corms were soaked for 24 hours in solutions containing 0, 10, 20, 30 and 40 mmol L-1 of C from HA. The corms were planted in 10-dm³ plastic bags filled with substrate and kept in a greenhouse. Growth of shoots and roots was evaluated. The results showed that the use of HA accelerates growth, and anticipates and increases flowering of Gladiolus.

  4. Label Distribution in Tissues of Wheat Seedlings Cultivated with Tritium-Labeled Leonardite Humic Acid

    Science.gov (United States)

    Kulikova, Natalia A.; Abroskin, Dmitry P.; Badun, Gennady A.; Chernysheva, Maria G.; Korobkov, Viktor I.; Beer, Anton S.; Tsvetkova, Eugenia A.; Senik, Svetlana V.; Klein, Olga I.; Perminova, Irina V.

    2016-06-01

    Humic substances (HS) play important roles in the biotic-abiotic interactions of the root plant and soil contributing to plant adaptation to external environments. However, their mode of action on plants remains largely unknown. In this study the HS distribution in tissues of wheat seedlings was examined using tritium-labeled humic acid (HA) derived from leonardite (a variety of lignites) and microautoradiography (MAR). Preferential accumulation of labeled products from tritiated HA was found in the roots as compared to the shoots, and endodermis was shown to be the major control point for radial transport of label into vascular system of plant. Tritium was also found in the stele and xylem tissues indicating that labeled products from tritiated HA could be transported to shoot tissues via the transpiration stream. Treatment with HA lead to an increase in the content of polar lipids of photosynthetic membranes. The observed accumulation of labeled HA products in root endodermis and positive impact on lipid synthesis are consistent with prior reported observations on physiological effects of HS on plants such as enhanced growth and development of lateral roots and improvement/repairs of the photosynthetic status of plants under stress conditions.

  5. Chlorination of humic materials: Byproduct formation and chemical interpretations

    Science.gov (United States)

    Reckhow, D.A.; Singer, P.C.; Malcolm, R.L.

    1990-01-01

    Ten aquatic humic and fulvic acids were isolated and studied with respect to their reaction with chlorine. Yields of TOX, chloroform, trichloroacetic acid, dichloroacetic acid, dichloroacetonitrile, and 1,1,1-trichloropropanone were measured at pH 7 and 12. Humic acids produced higher concentrations than their corresponding fulvic acids of all byproducts except 1,1,1-trichloropropanone. Chlorine consumption and byproduct formation were related to fundamental chemical characteristics of the humic materials. A statistical model was proposed for activated aromatic content based on 13C NMR and base titration data. The values estimated from this model were found to be well correlated with chlorine consumption. Specific byproduct formation was related to UV absorbance, nitrogen content, or the activated aromatic content. ?? 1990 American Chemical Society.

  6. Humus accumulation, humification, and humic acid composition in soils of two post-mining chronosequences after coal mining

    Czech Academy of Sciences Publication Activity Database

    Abakumov, E.V.; Cajthaml, Tomáš; Brus, Jiří; Frouz, J.

    2013-01-01

    Roč. 13, č. 3 (2013), s. 491-500 ISSN 1439-0108 R&D Projects: GA MŠk 2B08023; GA MŠk LC06066 Institutional support: RVO:61388971 ; RVO:61389013 Keywords : Humus accumulation * Humic acids composition * Humification Subject RIV: EE - Microbiology, Virology; CD - Macromolecular Chemistry (UMCH-V) Impact factor: 2.107, year: 2013

  7. Distinct Effects of Humic Acid on Transport and Retention of TiO2 Rutile Nanoparticles in Saturated Sand Columns

    Science.gov (United States)

    The distinct effects of humic acid (HA, 0−10 mg L−1) on the transport of titanium dioxide (rutile) nanoparticles (nTiO2) through saturated sand columns were observed under conditions of environmental relevance (ionic strength 3−200 mM NaCl, pH 5.7 and 9.0). Specifically, the tra...

  8. Distinct Effects of Humic Acid on Transport and Retention of TiO2 Rutile Nanoparticles in Saturated Sand Column

    Science.gov (United States)

    Distinct effects of humic acid (HA, 0 – 10 mg L-1) on the transport of titanium dioxide (rutile) nanoparticles (nTiO2) through saturated sand columns were observed under conditions of environmental relevance (ionic strength 3 – 200 mM NaCl, pH 5.7 and 9.0). Specifical...

  9. Effects of kaolinite and drying temperature on the persistence of soil water repellency induced by humic acids

    NARCIS (Netherlands)

    Lichner, L.; Babejová, N.; Dekker, L.W.

    2002-01-01

    The effects of kaolinite additions and drying temperature on the persistence of soil water repellency, induced by humic acids from peat, were assessed in this study. It was found that additions of 5 and 10% kaolinite (referred to as the most effective material in combating the water repellency) did

  10. Intraparticulate Metal Speciation Analysis of Soft Complexing Nanoparticles. The Intrinsic Chemical Heterogeneity of Metal-Humic Acid Complexes

    DEFF Research Database (Denmark)

    Town, R. M.; van Leeuwen, Herman P.

    2016-01-01

    The counterion condensation-Dorman (CCD) model for the electrostatic features of soft, charged nanopartides (NPs) is applied to the determination of the intrinsic stability constants, kit, for inner-sphere Cd(II) and Cu(II) complexes with humic acid NPs. The novel CCD model accounts for the stron...

  11. Analytical pyrolysis and thermally assisted hydrolysis and methylation of EUROSOIL humic acid samples: a key to their source

    NARCIS (Netherlands)

    Buurman, P.; Nierop, K.G.J.; Kaal, J.; Senesi, S.I.

    2009-01-01

    Humic acids have been widely investigated by spectroscopic methods, especially NMR and FTIR, and they are known to show significant differences according to their origin. Low resolution methods such as NMR and FTIR, however cannot easily distinguish different input sources or establish relations

  12. Effect of compost and humic acid in mobility and concentration of cadmium and chromium in soil and plant

    Directory of Open Access Journals (Sweden)

    A. Chaab

    2016-12-01

    Full Text Available The effect of compost and humic acid in mobility and concentration of cadmium and chromium in contaminated soil were investigated. Experiment was carried out with three levels of soil cadmium and chromium and two organic matters (compost and humic acid. The study was performed in a randomized complete block design with 3 replicates. Results indicated that application of organic substances enhanced movement of cadmium and chromium in soil column. Humic acid is more effective than compost on the mobility of cadmium and chromium in soil. Mobility of cadmium and chromium in the lower depths of soil column were increased. Cadmium and chromium concentration in shoots and roots enhanced due to increasing those concentration in soil and application of organic substances. Increase in cadmium in shoots can be attributed to the high mobility of this element in maize plant. Maize root chromium concentration was greater than shoot chromium concentration. Humic acid was more effective than compost as cadmium and chromium concentration in root and shoot was concerned. Low mobility of chromium in plant and accumulation of chromium in roots can be reasons of decreasing of chromium concentration in shoot of plant and its bioaccumulation.

  13. Interaction between lysozyme and humic acid in layer-by-layer assemblies: Effects of pH and ionic strength

    NARCIS (Netherlands)

    Tan, W.F.; Norde, W.; Koopal, L.K.

    2014-01-01

    The interaction between protein and soluble organic matter is studied through layer-by-layer assembly of lysozyme (LSZ) and purified Aldrich humic acid (PAHA) at a solid surface (2-D) and in solution (3-D). By bringing a silica surface in alternating contact with solutions of LSZ and PAHA a

  14. Interaction between lysozyme and humic acid in layer-by-layer assemblies : Effects of pH and ionic strength

    NARCIS (Netherlands)

    Tan, Wenfeng; Norde, Willem; Koopal, Luuk K.

    2014-01-01

    The interaction between protein and soluble organic matter is studied through layer-by-layer assembly of lysozyme (LSZ) and purified Aldrich humic acid (PAHA) at a solid surface (2-D) and in solution (3-D). By bringing a silica surface in alternating contact with solutions of LSZ and PAHA a

  15. Effective removal of phosphate from aqueous solution using humic acid coated magnetite nanoparticles.

    Science.gov (United States)

    Rashid, Mamun; Price, Nathaniel T; Gracia Pinilla, Miguel Ángel; O'Shea, Kevin E

    2017-10-15

    Effective removal of excess phosphate from water is critical to counteract eutrophication and restore water quality. In this study, low cost, environmentally friendly humic acid coated magnetite nanoparticles (HA-MNP) were synthesized and applied for the remediation of phosphate from aqueous media. The HA-MNPs, characterized by FTIR, TEM and HAADF-STEM showed the extensive coating of humic acid on the magnetite surface. The magnetic nanoparticles with diameters of 7-12 nm could be easily separated from the reaction mixture by using a simple hand held magnet. Adsorption studies demonstrate the fast and effective separation of phosphate with maximum adsorption capacity of 28.9 mg/g at pH 6.6. The adsorption behavior follows the Freundlich isotherm suggesting the formation of non-uniform multilayers of phosphate on the heterogeneous surface of HA-MNP. The adsorption kinetic fits the pseudo-second order model well with rate constants of 0.206 ± 0.003, 0.073 ± 0.002 and 0.061 ± 0.003 g mg -1 min -1 for phosphate (P) concentrations of 2, 5 and 10 mg/L respectively. The removal of phosphate was found higher at acidic and neutral pH compared to basic conditions. The nanoparticles exhibit good selectivity and adsorption efficiency for phosphate in presence of co-existing ions such as Cl - , SO 4 2- and NO 3 - with some inhibition effect by CO 3 2- . The effect of temperature on the adsorption reveals that the process is endothermic and spontaneous. HA-MNPs are promising, simple, environmentally friendly materials for the removal of phosphate from aqueous media. Copyright © 2017. Published by Elsevier Ltd.

  16. Acclimation of croton and hibiscus seedlings in response to the application of indobultiric acid and humic acid for rooting

    Directory of Open Access Journals (Sweden)

    Lílian Estrela Borges Baldotto

    2015-06-01

    Full Text Available The vegetative propagation of ornamental plants can be accelerated by applying plant growth regulators. Amongst them, the use of auxins, plant hormones with physiological effects on cell elongation and rooting have stood out. Alternatively, the application of humic acids, bioactive fraction of soil organic matter, also results in increases in rooting cuttings of ornamental plants. The objective of this work was to study the growth characteristics and the nutritional contents of croton and hibiscus plants during acclimation of seedlings in response to different concentrations of indolebutyric acid (IBA and humic acid (HA applied to cuttings for rooting. The experiment was conducted in greenhouse, and the apical stem cuttings were treated with solutions with concentrations of 0, 250, 500, 1000 and 2000 mg L-1of IBA and 0, 10, 20, 30 and 40 mg L-1 of C from HA. At 45 days of rooting in carbonized rice husk, they were individually transferred to plastic bags of 2.0 dm3 containing a mixture of soil: sand: manure (2: 1: 1 as substrate. At 90 days of acclimation, the plants were collected for measurement of growth and nutritional variables. The results showed that the application of the IBA stimulates the absorption of nutrients and growth of croton cuttings and transplanted hibiscus, contributing to formation of vigorous seedlings. A similar response occurred with the application of HA in hibiscus cuttings

  17. Influence of natural humic acids and synthetic phenolic polymers on fibrinolysis

    Science.gov (United States)

    Klöcking, Hans-Peter

    The influence of synthetic and natural phenolic polymers on the release of plasminogen activator was studied in an isolated, perfused, vascular preparation (pig ear). Of the tested synthetic phenolic polymers, the oxidation products of caffeic acid (KOP) and 3,4-dihydroxyphenylacetic acid (3,4-DHPOP), at a concentration of 50 µg/ml perfusate, were able to increase the plasminogen activator activity by 70%. The oxidation products of chlorogenic acid (CHOP), hydrocaffeic acid (HYKOP), pyrogallol (PYROP) and gallic acid (GALOP), at the same concentration, exerted no influence on the release of plasminogen activator. Of the naturally occurring humic acids, the influence of sodium humate was within the same order of magnitude as KOP and 3,4-DHPOP. Ammonium humate was able to increase the plasminogen activator release only at a concentration of 100 µg/ml perfusate. In rats, the t-PA activity increased after i.v. application of 10 mg/kg of KOP, Na-HS or NH4-HS.

  18. The role of humic acids and biochar as specific sorbents of pesticides in soil

    Science.gov (United States)

    Ćwieląg-Piasecka, Irmina; Dębicka, Magdalena; Medyńska-Jureszek, Agnieszka; Weber, Jerzy; Jamroz, Elżbieta

    2017-04-01

    Pesticides are widely used in agriculture to prevent or control different pests and increase yield as well as products quality. Despite of the strict regulations concerning sustainable use of plant protection products, their residues are very often present in soil. Depending on their chemical and physical properties, they undergo various transformations in the soil. This results in their retention on different sorbents, degradation by microorganisms or leaching to the groundwater. Biochar is a carbon-rich byproduct of thermal biomass conversion, and due to its high sorption properties can be an efficient sorbent for pesticides in soil. The aim of the research was to compare the effect of two types of organic sorbents - humic acids (HA) and biochar (BC) - in sorption-desorption processes of different pesticides, which residues are commonly present in arable soils and thus are potentially harmful for the environment. The humic acids were extracted from topsoil horizon of arable cambisoil derived from loam (Lower Silesia, Poland) by Shnitzer's method, then purified using XAD resin and freeze-dried. Biochar was produced from wheat straw in gasification process at 550˚C, remaining 30 minutes in the reactor. Investigated pesticides belong to three different chemical classes: carbamates (carbaryl and carbofuran), phenoxyacetic acids (2,4-D and MCPA) and aniline derivatives (metolachlor), and are active substances of commonly used plant protection products in agriculture. To obtain the experimental goal the sorption experiment was conducted. To the investigated organic matter samples (HA or BC) aliquots of pesticides solutions in 10M CaCl2 were added and the mixtures were shaken for 24h. Afterwards the samples were centrifuged and supernatants analyzed by LC-MS/MS for the pesticides content. After that the same samples were refilled with CaCl2 and analyzed in the same way for desorption studies. Humic acids exhibited strong affinity for the ionic substances (2,4-D, MCPA

  19. Atmospheric HULIS: How humic-like are they? A comprehensive and critical review

    Directory of Open Access Journals (Sweden)

    E. R. Graber

    2006-01-01

    Full Text Available A class of organic molecules extracted from atmospheric aerosol particles and isolated from fog and cloud water has been termed HUmic-LIke Substances (HULIS due to a certain resemblance to terrestrial and aquatic humic and fulvic acids. In light of the interest that this class of atmospheric compounds currently attracts, we comprehensively review HULIS properties, as well as laboratory and field investigations concerning their formation and characterization in atmospheric samples. While sharing some important features such as polyacidic nature, accumulating evidence suggests that atmospheric HULIS differ substantially from terrestrial and aquatic humic substances. Major differences between HULIS and humic substances, including smaller average molecular weight, lower aromatic moiety content, greater surface activity, better droplet activation ability, as well as others, are highlighted. Several alternatives are proposed that may explain such differences: (1 the possibility that mono- and di-carboxylic acids and mineral acids abundant in the atmosphere prevent the formation of large humic 'supramolecular associations'; (2 that large humic macromolecules are destroyed in the atmosphere by UV radiation, O3, and OH- radicals; (3 that 'HULIS' actually consists of a complex, unresolved mixture of relatively small molecules rather than macromolecular entities; and (4 that HULIS formed via abiotic and short-lived oxidative reaction pathways differ substantially from humic substances formed over long time periods via biologically-mediated reactions. It should also be recalled that the vast majority of studies of HULIS relate to the water soluble fraction, which would include only the fulvic acid fraction of humic substances, and exclude the humic acid (base-soluble and humin (insoluble fractions of humic substances. A significant effort towards adopting standard extraction and characterization methods is required to develop a better and meaningful

  20. Effect of soil fulvic and humic acid on binding of Pb to goethite–water interface: Linear additivity and volume fractions of HS in the Stern layer

    NARCIS (Netherlands)

    Xiong, J.; Koopal, L.K.; Weng, L.; Wang, J.; Tan, W.

    2015-01-01

    The effects of soil fulvic (JGFA) and humic acid (JGHA) on Pb binding to goethite were investigated with batch experiments and modeling. The CD-MUSIC and NICA-Donnan model could describe the Pb binding to, respectively, the binary Pb–goethite and Pb–HS systems. The adsorption of humic substances

  1. Catalysis of PAH biodegradation by humic acid shown in synchrotron infrared studies

    Energy Technology Data Exchange (ETDEWEB)

    Holman, Hoi-Ying N.; Nieman, Karl; Sorensen, Darwin L.; Miller, Charles D.; Martin, Michael C.; Borch, Thomas; McKinney, Wayne R.; Sims, Ronald C.

    2001-09-26

    The role of humic acid (HA) in the biodegradation of toxic polycyclic aromatic hydrocarbons (PAHs) has been the subject of controversy, particularly in unsaturated environments. By utilizing an infrared spectromicroscope and a very bright, nondestructive synchrotron photon source, we monitored in situ and, over time, the influence of HA on the progression of degradation of pyrene (a model PAH) by a bacterial colony on a magnetite surface. Our results indicate that HA dramatically shortens the onset time for PAH biodegradation from 168 to 2 h. In the absence of HA, it takes the bacteria about 168 h to produce sufficient glycolipids to solubilize pyrene and make it bioavailable for biodegradation. These results will have large implications for the bioremediation of contaminated soils.

  2. An efficient approach to the quantitative analysis of humic acid in water.

    Science.gov (United States)

    Wang, Xue; Li, Bao Qiong; Zhai, Hong Lin; Xiong, Meng Yi; Liu, Ying

    2016-01-01

    Rayleigh and Raman scatterings inevitably appear in fluorescence measurements, which make the quantitative analysis more difficult, especially in the overlap of target signals and scattering signals. Based on the grayscale images of three-dimensional fluorescence spectra, the linear model with two selected Zernike moments was established for the determination of humic acid, and applied to the quantitative analysis of the real sample taken from the Yellow River. The correlation coefficient (R(2)) and leave-one-out cross validation correlation coefficient (R(2)cv) were up to 0.9994 and 0.9987, respectively. The average recoveries were reached 96.28%. Compared with N-way partial least square and alternating trilinear decomposition methods, our approach was immune from the scattering and noise signals owing to its powerful multi-resolution characteristic and the obtained results were more reliable and accurate, which could be applied in food analyses. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Characterization of Humic Acid Modified Bentonite Binder for Iron Ore Pelletization

    Science.gov (United States)

    Sun, Yang; Xu, Bin; Zhang, Yuanbo; Liu, Bingbing; Zhou, Youlian; Su, Zijian

    Anew kind of iron ore pellet binder named humic acid modifying bentonite (HA-MB) has been developed by the author's group, which has the advantages of both organic HA and inorganic bentonite. The green pellet strength can be obviously improved by using the HA-MB binder. In this study, the detection of the characterization of HA-MB was conducted by zeta-potential, TG-DSC, FTIR, XRD, etc. The addition of HA was able to change the zeta-potential of bentonite. And HA-MB had more weight loss than that of bentonite according to TG-DSC analysis. Some functional groups of HA were also found in the FTIR spectrum of HA-MB. XRD result indicated that d(001) of crystal layer of bentonite had apparently altered due to the addition of HA.

  4. Free and esterified aliphatic carboxylic acids in humin and humic acids from a peat sample as revealed by pyrolysis with tetramethylammonium hydroxide or tetrathylammonium acetate

    Energy Technology Data Exchange (ETDEWEB)

    Grasset, L.; Guignard, C.; Ambles, A. [UMR 6514, Faculte des Sciences, Poitiers (France). Lab. de Synthese et Reactivite Substances Naturelles

    2002-07-01

    The combination of TMAH thermochemolysis and TEAAc treatment makes it possible to discriminate between the different forms of mono- and dicarboxylic acids present in the structure of humin and humic acids, that is, ''free'' uncombined acids, methyl or ethyl esters present as tightly trapped molecules within the matrix, or acids chemically linked to the matrix by ester groups. The results confirm that ester groups are involved in the structure of humin and humic acids. The cross-linking of moieties originating from microbial metabolism or inherited from higher plants is partly ensured by these chemical groups. On the other hand, significant amounts of fatty monocarboxylic acids and linear dicarboxylic acids are present as free acids in the humin of the studied sample. Humin contains also fatty acid methyl esters. Free, uncombined {alpha},{omega}-dicarboxylic acids were only found in humin. (author)

  5. Effects of humic acid on the interactions between zinc oxide nanoparticles and bacterial biofilms

    Energy Technology Data Exchange (ETDEWEB)

    Ouyang, Kai; Yu, Xiao-Ying; Zhu, Yunlin; Gao, Chunhui; Huang, Qiaoyun; Cai, Peng

    2017-12-01

    The effects of humic acid (HA) on interactions between ZnO nanoparticles (ZnO NPs) and Pseudomonas putida KT2440 biofilms at different maturity stages were investigated. Three stages of biofilm development were identified according to bacterial adenosine triphosphate (ATP) activity associated with biofilm development process. In the initial biofilm stage 1, the ATP content of bacteria was reduced by more than 90% when biofilms were exposed to ZnO NPs. However, in the mature biofilm stages 2 and 3, the ATP content was only slightly decreased. Biofilms at stage 3 exhibited less susceptibility to ZnO NPs than biofilms at stage 2. These results suggest that more mature biofilms have a significantly higher tolerance to ZnO NPs compared to young biofilms. In addition, biofilms with intact extracellular poly-meric substances (EPS) showed higher tolerance to ZnO NPs than those without EPS, indicating that EPS play a key role in alleviating the toxic effects of ZnO NPs. In both pure ZnO NPs and ZnO-HA mixtures, dissolved Zn2+ originating from the NPs significantly contributed to the overall toxicity. The presence of HA dramatically decreased the toxicity of ZnO NPs due to the binding of Zn2+ on HA. The combined results from this work suggest that the biofilm maturity stages and environmental constituents (such as humic acid) are important factors to consider when evaluating potential risks of NPs to ecological systems.

  6. Aminopropyl-Silica Hybrid Particles as Supports for Humic Acids Immobilization

    Directory of Open Access Journals (Sweden)

    Mónika Sándor

    2016-01-01

    Full Text Available A series of aminopropyl-functionalized silica nanoparticles were prepared through a basic two step sol-gel process in water. Prior to being aminopropyl-functionalized, silica particles with an average diameter of 549 nm were prepared from tetraethyl orthosilicate (TEOS, using a Stöber method. In a second step, aminopropyl-silica particles were prepared by silanization with 3-aminopropyltriethoxysilane (APTES, added drop by drop to the sol-gel mixture. The synthesized amino-functionalized silica particles are intended to be used as supports for immobilization of humic acids (HA, through electrostatic bonds. Furthermore, by inserting beside APTES, unhydrolysable mono-, di- or trifunctional alkylsilanes (methyltriethoxy silane (MeTES, trimethylethoxysilane (Me3ES, diethoxydimethylsilane (Me2DES and 1,2-bis(triethoxysilylethane (BETES onto silica particles surface, the spacing of the free amino groups was intended in order to facilitate their interaction with HA large molecules. Two sorts of HA were used for evaluating the immobilization capacity of the novel aminosilane supports. The results proved the efficient functionalization of silica nanoparticles with amino groups and showed that the immobilization of the two tested types of humic acid substances was well achieved for all the TEOS/APTES = 20/1 (molar ratio silica hybrids having or not having the amino functions spaced by alkyl groups. It was shown that the density of aminopropyl functions is low enough at this low APTES fraction and do not require a further spacing by alkyl groups. Moreover, all the hybrids having negative zeta potential values exhibited low interaction with HA molecules.

  7. Soil remediation: humic acids as natural surfactants in the washings of highly contaminated soils

    International Nuclear Information System (INIS)

    Conte, Pellegrino; Agretto, Anna; Spaccini, Riccardo; Piccolo, Alessandro

    2005-01-01

    The remediation of the highly contaminated site around the former chemical plant of ACNA (near Savona) in Northern Italy is a top priority in Italy. The aim of the present work was to contribute in finding innovative and environmental-friendly technology to remediate soils from the ACNA contaminated site. Two soils sampled from the ACNA site (A and B), differing in texture and amount and type of organic contaminants, were subjected to soil washings by comparing the removal efficiency of water, two synthetic surfactants, sodium dodecylsulphate (SDS) and Triton X-100 (TX100), and a solution of a natural surfactant, a humic acid (HA) at its critical micelle concentration (CMC). The extraction of pollutants by sonication and soxhlet was conducted before and after the soil washings. Soil A was richer in polycyclic aromatic hydrocarbons, whereas soil B had a larger content of thiophenes. Sonication resulted more analytically efficient in the fine-textured soil B. The coarse-textured soil A was extracted with a general equal efficiency also by soxhlet. Clean-up by water was unable to exhaustively remove contaminants from the two soils, whereas all the organic surfactants revealed very similar efficiencies (up to 90%) in the removal of the contaminants from the soils. Hence, the use of solutions of natural HAs appears as a better choice for soil washings of highly polluted soils due to their additional capacity to promote microbial activity, in contrast to synthetic surfactants, for a further natural attenuation in washed soils. - Solutions of natural humic acids appear to be a better choice for washing highly polluted soils

  8. Enhanced transport of ferrihydrite colloid by chain-shaped humic acid colloid in saturated porous media.

    Science.gov (United States)

    Ma, Jie; Guo, Huaming; Lei, Mei; Li, Yongtao; Weng, Liping; Chen, Yali; Ma, Yuling; Deng, Yingxuan; Feng, Xiaojuan; Xiu, Wei

    2018-04-15

    Both humic acid and colloid particle size effectively regulate colloid transport. However, little is known about effect of particle size and configuration of humic acid colloid (HA colloid ) on enhanced-transport of ferrihydrite colloid (FH colloid ) in porous media. Co-transport of HA colloid and FH colloid at different pH was systematically investigated by monitoring breakthrough curves (BTCs) in saturated sand columns. The colloid transport model and the (X)DLVO theory were used to reveal the mechanism of HA colloid -enhanced FH colloid transport in the columns. Results showed that HA colloid enhanced FH colloid transport in neutral and alkaline conditions. In neutral conditions, small HA colloid (F-HA colloid ) with chain-shaped structure enhanced FH colloid transport more prominently than pristine granular HA colloid . The chain-shaped F-HA colloid caused osmotic repulsion and elastic-steric repulsion between colloids and sand, leading to enhanced transport. However, the granular HA colloid readily occurred as deposition due to attachment and straining, which decreased the enhanced transport of FH colloid . In alkaline conditions, both HA colloid and F-HA colloid were chain-shaped, with longer chains of HA colloid than F-HA colloid . Ferrihydrite colloid transport was enhanced by HA colloid more significantly than F-HA colloid due to stronger repulsion between mixed HA colloid -FH colloid and sand. It suggested that regulation of particle size and morphology of HA colloid would enhance FH colloid transport and further help in understanding FH colloid -facilitated contaminants transport in porous media. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Effects of humic substances on the migration of radionuclides: Complexation of actinides with humic substances. 3. Progress report

    International Nuclear Information System (INIS)

    Kim, J.I.; Rhee, D.S.; Buckau, G.; Moulin, V.; Tits, J.; Decambox, P.; Franz, C.; Herrmann, G.; Trautmann, N.; Dierckx, A.; Vancluysen, J.; Maes, A.

    1993-03-01

    The aim of the present research programme is to study the complexation behaviour of actinide ions with humic substances in natural aquifer systems and hence to quantify the effect of humic substances on the actinide migration. Aquatic humic substances commonly found in all groundwaters in different concentrations have a strong tendency towards complexation with actinide ions. This is one of the major geochemical reactions but hitherto least quantified. Therefore, the effect of humic substances on the actinide migration is poorly understood. In the present research programme the complexation of actinide ions with humic substances will be described thermodynamically. This description will be based on a model being as simple as possible to allow an easy introduction of the resulting reaction constants into geochemical modelling of the actinide migration. This programme is a continuation of the activities of the COCO group in the second phase of the CEC-MIRAGE project. The programme consists of the following three main tasks: Task 1: Complexation reactions of actinide ions with well characterized reference and site-specific humic and fulvic acids; Task 2: Competition reactions with major cations in natural groundwaters; Task 3: Validation of the complexation data in natural aquatic systems by comparison of calculation with spectroscopic experiment. (orig./EF)

  10. Kinetics of the oxidative hydroxylation of tetraphosphorus in the presence of copper(II chloride modified by humic (fulvo- acid

    Directory of Open Access Journals (Sweden)

    Zhaksyntay Kairbekov

    2012-12-01

    Full Text Available It was established that in mild conditions (50-70 oC, РО2= 1 atm white phosphorus effectively is oxidized by oxygen in water-toluene solutions of copper(II chloride modified by humic (fulvo- acid to give mainly phosphoric acid. Humic (fulvo- acid was extracted from brown coal of domestic deposit Kiyakty. For determination of optimum parameters of fulvo-acid extraction the laboratory experiments were carried out using the method of experiment planning. The kinetics, intermediate and final products, optimum conditions of new catalytic reaction of P4 oxidation by oxygen in water medium were defined by kinetics, volumometry, redox-potentiometry, 31Р{1Н} NMR spectroscopy and  titration. 

  11. Complexation of Hg (II) ions with humic acids of tundra soils

    Science.gov (United States)

    Vasilevich, Roman

    2013-04-01

    Humic acids (HA) play an important role in processes of heavy metals migration, controlling their geochemical streams in environment. Accumulative and detoxification abilities of HA to heavy metals are realized by means of formation of steady complexes salycylate and pyrocatechin types. Modern researches show that HA of the Arctic and Subarctic areas are poorly enriched by aromatic frames, so and metalbinding centres. The work purpose is to study interaction mechanisms of Hg (II) ions with HA and to define tread possibilities of a tundra soils humic acids. It is established that binding ability of Hg (II) ions depends on concentration of an element, on quantity of functional groups in peripheral and nuclear parts of HA molecule as well as on a solution pH. coomplexation proceeds at pH 2.5-3.5 efficiently. On the basis of kinetic models it is shown that HA interaction with Hg (II) ions, at microconcentration of a pollutant (0.025-5.0 mkmol/dm3), has a zero order of reaction. Rate of a reaction does not depend on initial components concentration and is defined by process of Hg (II) ions diffusion to organic ligands. High correlation of a HA sorption capacity to Hg (II) ions is observed: with the nitrogen content and maintenance of amino groups (according to a 13C-NMR, element composition) and negative correlation - with degree of HA aromaticity. It testifies to primary binding of Hg (II) ions by amino-acid fragments of a HA molecule peripheral part. When concentration of Hg (II) ions increases, binding proceeds on carboxylic and phenolic groups of a molecule nuclear part. Higher order of kinetic models reaction and FTIR spectroscopy data testify to it. Comparison of FTIR spectra of HA preparations and mercury humates, shows that Hg (II) ions binding in humate complexes is carried out mainly by -COOH. Reduction of a spectral line intensity not ionized -COOH at 1700-1720 sm-1 and intensity increases of dissymetric valency vibration at 1610-1650 sm-1 diagnose increase

  12. Effect of Vermicompost Extract and Vermicompost-Derived Humic Acids on Seed Germination and Seedling Growth of Hemp

    Directory of Open Access Journals (Sweden)

    Ievinsh Gederts

    2017-08-01

    Full Text Available Hemp (Cannabis sativa L. cultivars grown for industrial use have recently emerged as a sustainable alternative source of industrial fibre and bioenergy, and is a highly valuable food and animal feed resource. The aim of the present study was to evaluate the effect of vermicompost extract, vermicompost mineral nutrient composition, and vermicompost-derived humic and fulvic acids on seed germination and growth of hemp seedlings. In general, separate application of all vermicompost components stimulated seed germination and hypocotyl and radicle growth, as well as increased chlorophyll concentration in cotyledons. Effective concentration range and the degree of stimulation varied significantly between the treatments. For practical purposes, application of vermicompost and vermicompost-derived extracts for stimulation of hemp growth could be useful at concentrations 5%, 0.05 mg·mL−1 and 1%, for vermicompost extract, humic acids and fulvic acids, respectively.

  13. Mitigation of Humic Acid Inhibition in Anaerobic Digestion of Cellulose by Addition of Various Salts

    NARCIS (Netherlands)

    Azman, S.; Khadem, A.F.; Zeeman, G.; Lier, van J.B.; Plugge, C.M.

    2015-01-01

    Humic compounds are inhibitory to the anaerobic hydrolysis of cellulosic biomass. In this study, the impact of salt addition to mitigate the inhibitory effects of humic compounds was investigated. The experiment was conducted using batch tests to monitor the anaerobic hydrolysis of cellulose in the

  14. Investigations of the uptake of transuranic radionuclides by humic and fulvic acids chemically immobilized on silica gel and their competitive release by complexing agents

    International Nuclear Information System (INIS)

    Bulman, R.A.; Szabo, G.; Clayton, R.F.; Clayton, C.R.

    1998-01-01

    The chemistry of the interactions of transuranic elements (TUs) with humic substances needs to be understood so that humate-mediated movement of transuranic radionuclides through the environment can be predicted. This paper reports the chemical immobilization on silica gel of humic and fulvic acids and evaluates the potential of these new materials for the retention of Pu and Am. In addition to the preparation of the foregoing immobilized humic substances, other low molecular weight metal-binding ligands have also been immobilized on silica gel to investigate the binding sites for transuranic elements (TUs) in humic substances. The X-ray photoelectron spectra (XPS) of Th(IV) complexed by humic acid and the immobilized humic acid are similar thus it appears that immobilization of humic acid does not generate any configurational changes in the Th(IV)-binding sites of the macromolecule. A variety of chelating agents partly mobilize these TUs sorbed on the solid phases. A batch method was used to determine the distribution coefficients (R d ) of Pu and Am between the silica gels and aqueous solutions of phosphate and citrate. The effects of the immobilized ligands, the anions and pH in the solution on sorption were assessed. Distributed coefficients (R d ) for the uptake of Pu and Am by these prepared solid phases are, in some cases, of a similar order of magnitude as those determined for soil and particles suspended in terrestrial surface waters

  15. Effects of a sedimentary humic acid on plant growth: study of the general mechanisms of action upon root application in cucumber plants (Cucumis Sativus l. Cv Ashley).

    OpenAIRE

    Olaetxea-Indaburu, M. (Maite); Baigorri-Ekisoáin, R. (Roberto); Garcia-Mina, J.M. (José María)

    2015-01-01

    HS (humic substances) constitute one of the most abundant forms of organic matter in the biosphere. Many studies reported the ability of humic acids (HAs) isolated from HS to affect plant the plant development of diverse plant species. However, the mechanism of action that is behind these events is scarcely understood and it is not integrated into a holistic view. To this end, the aim of this work was to study the mechanism of action of an specific sedimentary humic acid (SHA) under roots ...

  16. Sorption mechanisms of phenanthrene, lindane, and atrazine with various humic acid fractions from a single soil sample.

    Science.gov (United States)

    Wang, Xilong; Guo, Xiaoying; Yang, Yu; Tao, Shu; Xing, Baoshan

    2011-03-15

    The sorption behavior of organic compounds (phenanthrene, lindane, and atrazine) to sequentially extracted humic acids and humin from a peat soil was examined. The elemental composition, XPS and (13)C NMR data of sorbents combined with sorption isotherm data of the tested compounds show that nonspecific interactions govern sorption of phenanthrene and lindane by humic substances. Their sorption is dependent on surface and bulk alkyl carbon contents of the sorbents, rather than aromatic carbon. Sorption of atrazine by these sorbents, however, is regulated by polar interactions (e.g., hydrogen bonding). Carboxylic and phenolic moieties are key components for H-bonding formation. Thermal analysis reveals that sorption of apolar (i.e., phenanthrene and lindane) and polar (i.e., atrazine) compounds by humic substances exhibit dissimilar relationships with condensation and thermal stability of sorption domains, emphasizing the major influence of domain spatial arrangement on sorption of organic compounds with distinct polarity. Results of pH-dependent sorption indicate that reduction in sorption of atrazine by the tested sorbents is more evident than phenanthrene with increasing pH, supporting the dependence of organic compound sorption on its polarity and structure. This study highlights the different interaction mechanisms of apolar and polar organic compounds with humic substances.

  17. Protective Effect of Humic acid and Chitosan on Radish (Raphanus sativus, L. var. sativus Plants Subjected to Cadmium Stress

    Directory of Open Access Journals (Sweden)

    A.M. EL-Gahmery

    2011-05-01

    Full Text Available BackgroundHumic acid or chitosan has been shown to increase plant growth, yield and improving physiological processes in plant, but its roles on alleviating the harmful effect of cadmium on plant growth and some physiological processes in plants is very rare. Pot experiments were conducted to study the role of 100 and 200 mg/kg dry soil from either humic acid or chitosan on counteracted the harmful effects of cadmium levels (100 and 150 mg/kg dry soil on radish plant growth and some physiological charactersResultsCadmium at 100 and 150 mg kg-1 soil decreased significantly length, fresh and dry weights of shoot and root systems as well as leaf number per plant in both seasons. Chlorophyll, total sugars, nitrogen, phosphorus, potassium, relative water content, water deficit percentage and soluble proteins as well as total amino acids contents were also decreased. Meanwhile, cadmium concentration in plants was increased. On the other hand, application of chitosan or humic acid as soil addition at the concentration of 100 or 200 mg kg-1 increased all the above mentioned parameters and decreased cadmium concentrations in plant tissues. Chitosan at 200 mg kg-1 was the most effective than humic acid at both concentrations in counteracting the harmful effect of cadmium stress on radish plant growth.ConclusionIn conclusion, both natural chelators, in particular, chitosan at 200 mg/kg dry soil can increase the capacity of radish plant to survive under cadmium stress due to chelating the Cd in the soil, and then reduced Cd bio-availability.

  18. Potential Regulatory Role of Gibberellic and Humic Acids in Sprouting of Chlorophytum borivilianum Tubers

    Directory of Open Access Journals (Sweden)

    Jaafar Juju Nakasha

    2014-01-01

    Full Text Available Tubers of safed musli (Chlorophytum borivilianum were immersed in three different concentrations of gibberellic acid (GA3 or humic acid (HA prior to planting. The highest concentration of GA3 (20 mg L-1 and all concentrations of HA (5, 10, and 15% appeared to hasten tuber sprouting and promote uniform sprouting pattern. The use of 20 mg L-1 GA3 or 15% HA successfully improved sprouting and mean sprouting time. Safed musli growth and development was improved through the increase in the number of leaves, total leaf area, leaf area index, and total fibrous root length. This directly influenced the number of new tubers formed. The use of 20 mg L-1 GA3 or 15% HA gave similar response with nonsignificant difference among them. However, due to the cost of production, the result from this study suggests that 15% HA should be used to obtain improved sprouting percentage, homogeneous stand establishment, efficient plant growth and development, and increased yield of safed musli.

  19. Potential regulatory role of gibberellic and humic acids in sprouting of Chlorophytum borivilianum tubers.

    Science.gov (United States)

    Nakasha, Jaafar Juju; Sinniah, Uma Rani; Puteh, Adam; Hassan, Siti Aishah

    2014-01-01

    Tubers of safed musli (Chlorophytum borivilianum) were immersed in three different concentrations of gibberellic acid (GA3) or humic acid (HA) prior to planting. The highest concentration of GA3 (20 mg L(-1)) and all concentrations of HA (5, 10, and 15%) appeared to hasten tuber sprouting and promote uniform sprouting pattern. The use of 20 mg L(-1) GA3 or 15% HA successfully improved sprouting and mean sprouting time. Safed musli growth and development was improved through the increase in the number of leaves, total leaf area, leaf area index, and total fibrous root length. This directly influenced the number of new tubers formed. The use of 20 mg L(-1) GA3 or 15% HA gave similar response with nonsignificant difference among them. However, due to the cost of production, the result from this study suggests that 15% HA should be used to obtain improved sprouting percentage, homogeneous stand establishment, efficient plant growth and development, and increased yield of safed musli.

  20. Removal of humic and tannic acids by adsorption-coagulation combined systems with activated biochar.

    Science.gov (United States)

    Jung, Chanil; Phal, Narong; Oh, Jeill; Chu, Kyoung Hoon; Jang, Min; Yoon, Yeomin

    2015-12-30

    Despite recent interest in transforming biomass into bio-oil and syngas, there is inadequate information on the compatibility of byproducts (e.g., biochar) with agriculture and water purification infrastructures. A pyrolysis at 300°C yields efficient production of biochar, and its physicochemical properties can be improved by chemical activation, resulting in a suitable adsorbent for the removal of natural organic matter (NOM), including hydrophobic and hydrophilic substances, such as humic acids (HA) and tannic acids (TA), respectively. In this study, the adsorption affinities of different HA and TA combinations in NOM solutions were evaluated, and higher adsorption affinity of TA onto activated biochar (AB) produced in the laboratory was observed due to its superior chemisorption tendencies and size-exclusion effects compared with that of HA, whereas hydrophobic interactions between adsorbent and adsorbate were deficient. Assessment of the AB role in an adsorption-coagulation hybrid system as nuclei for coagulation in the presence of aluminum sulfate (alum) showed a synergistic effect in a HA-dominated NOM solution. An AB-alum hybrid system with a high proportion of HA in the NOM solution may be applicable as an end-of-pipe solution. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Three-dimensional fluorescence analysis of chernozem humic acids and their electrophoretic fractions

    Science.gov (United States)

    Trubetskoi, O. A.; Trubetskaya, O. E.

    2017-09-01

    Polyacrylamide gel electrophoresis in combination with size-exclusion chromatography (SEC-PAGE) has been used to obtain stable electrophoretic fractions of different molecular size (MS) from chernozem humic acids (HAs). Three-dimensional fluorescence charts of chernozem HAs and their fractions have been obtained for the first time, and all fluorescence excitation-emission maxima have been identified in the excitation wavelength range of 250-500 nm. It has been found that fractionation by the SEC-PAGE method results in a nonuniform distribution of protein- and humin-like fluorescence of the original HA preparation among the electrophoretic fractions. The electrophoretic fractions of the highest and medium MSs have only the main protein-like fluorescence maximum and traces of humin-like fluorescence. In the electrophoretic fraction of the lowest MS, the intensity of protein-like fluorescence is low, but the major part of humin-like fluorescence is localized there. Relationships between the intensity of protein-like fluorescence and the weight distribution of amino acids have been revealed, as well as between the degree of aromaticity and the intensity of humin-like fluorescence in electrophoretic fractions of different MSs. The obtained relationships can be useful in the interpretation of the spatial structural organization and ecological functions of soil HAs.

  2. Nanotoxicity of graphene oxide: Assessing the influence of oxidation debris in the presence of humic acid.

    Science.gov (United States)

    Clemente, Zaira; Castro, Vera Lúcia S S; Franqui, Lidiane S; Silva, Cristiane A; Martinez, Diego Stéfani T

    2017-06-01

    This study sought to evaluate the toxicological effects of graphene oxide (GO) through tests with Danio rerio (zebrafish) embryos, considering the influence of the base washing treatment and the interaction with natural organic matter (i.e., humic acid, HA). A commercial sample of GO was refluxed with NaOH to remove oxidation debris (OD) byproducts, which resulted in a base washed GO sample (bw-GO). This process decreased the total oxygenated groups in bw-GO and its stability in water compared to GO. When tested in the presence of HA, both GO and bw-GO stabilities were enhanced in water. Although the embryo exposure showed no acute toxicity or malformation, the larvae exposed to GO showed a reduction in their overall length and acetylcholinesterase activity. In the presence of HA, GO also inhibited acid phosphatase activity. Our findings indicate a mitigation of material toxicity after OD removal. The difference in the biological effects may be related to the materials' bioavailability and biophysicochemical interactions. This study reports for the first time the critical influence of OD on the GO material biological reactivity and HA interaction, providing new data for nanomaterial environmental risk assessment and sustainable nanotechnology. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Spin Labeling ESR Investigation of a Role of Humic Acids at Covalent Binding of Xenobiotics to Soil

    Science.gov (United States)

    Aleksandrova, Olga

    2014-05-01

    The environmental risk of organic xenobiotic chemicals released into soils is controlled by their sorption and binding processes. However, the molecular mechanisms of reversible and irreversible interactions of xenobiotics with soil constituents and an influence of humic substances on this interaction are only partly understood. New methods and approaches aimed at understanding of molecular mechanisms in the soil environment and a role of humic substances in the sorption and binding processes are today required to manage and keep the quality of soil used and fertilized in agricultural industry. The paper presents a new approach of using stable ESR spin labels to investigate a role of humic substances in the interactions of organic xenobiotic chemicals with constituents of natural soil via the typical functional groups of xenobiotics, such as Amines. At the experiment, the nitroxide spin labels, such as TEMPO (2,2,6,6-Tetramethylpiperidin-1-oxyl), Amino-TEMPO (4-amino-2,2,6,6-Tetramethylpiperidin-1-oxyl) and Aniline spin labels (2,5,5-Trimethyl-2-(3-aminophenyl)pyrrolidin-1-oxyl), were added to samples of different natural soils, such luvisol, cambisol and chernozem. Amino-TEMPO and Aniline spin labels include the aliphatic amino and aromatic amino functional groups, respectively. A significant broadening of the ESR spectrum of Aniline spin labels incubated in different soils indicated a stable effect of covalent binding of the spin labels to soil constituents via the aromatic amino, whereas the ESR spectra of the other two spin labels were not broadened that pointed at the absence of covalent binding of spin labels via the aliphatic amino. As shown, a part of bound spin labels via the aromatic amino increased with increasing of the concentration of humic acids in soil. The same broadened signals were also be detected with the humic acids extracted from the investigated soils. A strong covalent binding of spin labels to humic substances via the aromatic amines was

  4. Adsorption of phenanthrene, 2-naphthol, and 1-naphthylamine to colloidal oxidized multiwalled carbon nanotubes: effects of humic acid and surfactant modification.

    Science.gov (United States)

    Hou, Lei; Zhu, Dongqiang; Wang, Ximeng; Wang, Lilin; Zhang, Chengdong; Chen, Wei

    2013-03-01

    Carbon nanotubes (CNTs) can exist in the form of colloidal suspension in aquatic environments, particularly in the presence of natural organic matter or surfactants, and may significantly affect the fate and transport of organic contaminants. In the present study, the authors examined the adsorption of phenanthrene, 2-naphthol, and 1-naphthylamine to three colloidal CNTs, including a stable suspension of oxidized multiwalled carbon nanotubes (O-MWNT), a humic acid (HA)-modified colloidal O-MWNT, and a sodium dodecyl sulfate (SDS)-modified colloidal O-MWNT. All three colloidal O-MWNTs exhibit strong adsorption affinities to the three test compounds (with K(OC) values orders of magnitude greater than those of natural organic matter), likely resulting from strong nonhydrophobic interactions such as π-π electron donor-acceptor interactions and Lewis acid-base interactions. When thoroughly mixed, HA (at ∼310 mg HA/g CNT) and SDS (at ∼750 mg SDS/g CNT) significantly affected the aggregation properties of O-MWNT, causing individually dispersed tubes to form a loosely entangled network. The effects of HA or SDS modification on adsorption are twofold. Adsorption of HA/SDS significantly reduces surface areas of O-MWNT; however, the entangled network allows adsorbate molecules to interact simultaneously with multiple tubes. An important implication is that humic substances and surfactant-like materials not only facilitate the formation of colloidal carbon nanoparticles but also affect how these colloidal carbon nanoparticles adsorb organic contaminants. Copyright © 2013 SETAC.

  5. Propriedades ácido-base e de complexação de ácidos húmico e fúlvico isolados de vermicomposto Acid/base and complexation properties of humic and fulvic acids isolated from vermicompost

    Directory of Open Access Journals (Sweden)

    Sandro de Miranda Colombo

    2007-10-01

    Full Text Available Proton binding properties of humic and fulvic acids were studied by potentiometric titration. Carboxylic groups were the predominant ionizable sites in comparison to phenolic and amine groups. Total acidity of fulvic acid was 12 x 10-3 mol g-1, a number significantly higher than that obtained for humic acid (5.2 x 10-3 mol g-1. Copper ion binding was evaluated at pH 4, 5 and 6 by potentiometric titration with an ion selective electrode for Cu(II. Differential stability constants and complexation capacities were systematically higher for humic acid, despite its lower number of ionizable sites in comparison with fulvic acid.

  6. [Effect of humic acid and coexistent cation on the adsorption of Pb (II) in wastewater onto bentonite].

    Science.gov (United States)

    Yue, Qin-Yan; Li, Ren-Bo; Gao, Bao-Yu; Yang, Jing; Li, Ying; Yu, Hui

    2008-07-01

    Both the physical-chemical properties and adsorption performance for lead of Na-bentonite have been studied in this paper. The results showed that the removal of lead in solution by use of bentonite was effective. The pH, concentrations of coexistent cations and humic acid, which could influence the adsorption process were also studied. The results indicate that the sorption of lead (II) on Na-bentonite increased as pH value increased, and increased with increasing humic acid concentration, while decreased with increasing coexistent cation concentration. The adsorption mechanism was investigated from thermodynamics, and it was founded that the sorption of lead (II) on Na-bentonite increased with increasing temperature and the Freundlich adsorption equation fit to the experimental data excellently. The thermodynamic parameters were calculated: deltaH = 0.959 4 kJ/mol, deltaS = 16.6113 kJ/(mol x K).

  7. Neptunium redox behavior and sorption onto goethite and hematite in the presence of humic acids with different hydroquinone content

    International Nuclear Information System (INIS)

    Khasanova, A.B.; Kalmykov, St.N.; Perminova, I.V.; Clark, S.B.

    2007-01-01

    The effect of humic acids (HA) on neptunium redox behavior and sorption onto hematite, α-Fe 2 O 3 , and goethite, α-FeOOH, colloids was established in batch sorption experiments that were carried out in broad pH interval. The sorption isotherms were provided for two samples of HA: commercial sample of leonardite humic acid and its hydroquinone-enriched derivative obtained using formaldehyde copolycondensation. The distribution of Np fitted the distribution of hydroquinone-enriched HA at low pH values in case of both solids while the influence of parent HA on Np sorption was negligible. This is due to Np(V) reduction upon interaction with hydroquinone-enriched derivative having higher reducing capacity compared to the parent HA. The order of components addition was found to be significant for Np retention

  8. Biotechnology humic acids-based electrospun carbon nanofibers as cost-efficient electrodes for lithium-ion batteries

    International Nuclear Information System (INIS)

    Zhao, Pin-Yi; Guo, Yan; Yu, Bao-Jun; Zhang, Jie; Wang, Cheng-Yang

    2016-01-01

    Bio-based, cost-effective carbon nanofibers are fabricated from polyacrylonitrile (PAN) – refined biotechnology humic acids (RB) via simple eletrospinning after stabilization and carbonization. The influence of PAN/RB mass ratios and heat-treatment temperatures (HTTs) on structure and morphology is systematically studied. Excitingly, a first discharge/charge capacity of 937.9/613.4 mAh g −1 (coulombic efficiency of 65.4%) is achieved at 20 mA g −1 for PB7/3-800 in lithium-ion batteries (LIBs). Meanwhile, a charge capacity of 348.2 mAh g −1 (about 89% retention ratio) remains even after 100 cycles at 0.1 A g −1 . It is demonstrated that biomass humic acids can be applied as a promising precursor to fabricate high performance, low-cost, as well as “green” carbon electrode material for LIBs.

  9. Fractal analysis of polyferric chloride-humic acid (PFC-HA) flocs in different topological spaces.

    Science.gov (United States)

    Wang, Yili; Lu, Jia; Baiyu, Du; Shi, Baoyou; Wang, Dongsheng

    2009-01-01

    The fractal dimensions in different topological spaces of polyferric chloride-humic acid (PFC-HA) flocs, formed in flocculating different kinds of humic acids (HA) water at different initial pH (9.0, 7.0, 5.0) and PFC dosages, were calculated by effective density-maximum diameter, image analysis, and N2 absorption-desorption methods, respectively. The mass fractal dimensions (Df) of PFC-HA flocs were calculated by bi-logarithm relation of effective density with maximum diameter and Logan empirical equation. The Df value was more than 2.0 at initial pH of 7.0, which was 11% and 13% higher than those at pH 9.0 and 5.0, respectively, indicating the most compact flocs formed in flocculated HA water at initial pH of 7.0. The image analysis for those flocs indicates that after flocculating the HA water at initial pH greater than 7.0 with PFC flocculant, the fractal dimensions of D2 (logA vs. logdL) and D3 (logVsphere VS. logdL) of PFC-HA flocs decreased with the increase of PFC dosages, and PFC-HA flocs showed a gradually looser structure. At the optimum dosage of PFC, the D2 (logA vs. logdL) values of the flocs show 14%-43% difference with their corresponding Df, and they even had different tendency with the change of initial pH values. However, the D2 values of the flocs formed at three different initial pH in HA solution had a same tendency with the corresponding Dr. Based on fractal Frenkel-Halsey-Hill (FHH) adsorption and desorption equations, the pore surface fractal dimensions (Ds) for dried powders of PFC-HA flocs formed in HA water with initial pH 9.0 and 7.0 were all close to 2.9421, and the Ds values of flocs formed at initial pH 5.0 were less than 2.3746. It indicated that the pore surface fractal dimensions of PFC-HA flocs dried powder mainly show the irregularity from the mesopore-size distribution and marcopore-size distribution.

  10. Effect of probiotics and humic acid on egg production and internal quality parameters of laying hens eggs

    Directory of Open Access Journals (Sweden)

    Henrieta Arpášová

    2016-10-01

    Full Text Available The aim of our experiment was to evaluate the influence of probiotic preparation based on lactobacillus, probiotic preparation based on enterococci or humic acid on egg production and selected internal egg quality parameters of laying hens hybrid Lohman Brown Lite. For housing hens (n ​​= 60 three storey enriched battery cage was used in which hens were divided in groups (n = 15. In the control group of hens complete feed mixtures without any additions were fed. In the first experimental group complete feed mixture was enriched with probiotic lactobacilli based preparation in a dose of 0.5 g.kg-1. In the second experimental group probiotic enterococci based preparation was added to the feed mixture at a dose of 0.5 g.kg-1. The third experimental group was enriched with 0.5% concentration of humic acid. All groups were fed ad libitum. Egg production and egg weight were recorded daily. Complete analysis of the table egg quality was used to evaluate quality parameters: yolk weight (g, yolk index, yolk colour (°HLR, albumen weight (g, Haugh Units (HU, albumen index. The results show that supplementation of feed mixture with both kind probiotics as well as humic acid increased egg production (P>0.05 (values of average intensity of laying in the order of the groups: 90.5; 91.9; 91.6 and 92.3 %. The addition of probiotics also positively influenced egg weight (P>0.05. The qualitative parameters of egg internal content were with probiotics or humic acids addition insignificantly influenced (P>0.05. Doses of supplements used in this study did not significant negatively influenced monitored egg quality parameters. Based on these findings and the beneficial effects of substances on the poultry health confirmed by other authors we recommend use of these substances as supplements to the feed mixtures for laying hens.

  11. Sorption-desorption of imidacloprid onto a lacustrine Egyptian soil and its clay and humic acid fractions.

    Science.gov (United States)

    Kandil, Mahrous M; El-Aswad, Ahmed F; Koskinen, William C

    2015-01-01

    Sorption-desorption of the insecticide imidacloprid 1-[(6-chloro-3-pyridinyl)-methyl]-N-nitro-2-imidazolidinimine onto a lacustrine sandy clay loam Egyptian soil and its clay and humic acid (HA) fractions was investigated in 24-h batch equilibrium experiments. Imidacloprid (IMDA) sorption-desorption isotherms onto the three sorbents were found to belong to a non-linear L-type and were best described by the Freundlich model. The value of the IMDA adsorption distribution coefficient, Kd(ads), varied according to its initial concentration and was ranged 40-84 for HA, 14-58 for clay and 1.85-4.15 for bulk soil. Freundlich sorption coefficient, Kf(ads), values were 63.0, 39.7 and 4.0 for HA, clay and bulk soil, respectively. The normalized soil Koc value for imidacloprid sorption was ∼800 indicating its slight mobility in soils. Nonlinear sorption isotherms were indicated by 1/n(ads) values clay and soil. In conclusion, although the humic acid fraction showed the highest capacity and affinity for imidacloprid sorption, the clay fraction contributed to approximately 95% of soil-sorbed insecticide. Clay and humic acid fractions were found to be the major two factors controlling IMDA sorption in soils. The slight mobility of IMDA in soils and the hysteresis phenomenon associated with the irreversibility of its sorption onto, mainly, clay and organic matter of soils make its leachability unlikely to occur.

  12. Fatty Acid Content of Indonesian Aquatic Microalgae

    Directory of Open Access Journals (Sweden)

    TRI PRARTONO

    2010-12-01

    Full Text Available High utilization of fossil fuel increases the level of carbon dioxide in the atmosphere and results in global warming phenomenon. These things establish the world's thought to look for the other alternative energy that can reduce the use of fossil fuel even to be replaced by the substitute. Recently, Indonesia has been doing the research of microalgae as a feedstock of an alternative biofuel. Fatty acid content that microalgae have is also high to produce biofuel. The steps used in this research is a 7 days cultivation, harvesting, extraction using hexane, and fatty acid identification using Gas Chromatography of microalgae species. Fatty acid component in some species such as Chlorella sp., Scenedesmus sp., Nannochloropsis sp., and Isochrysis sp. is between 0.21-29.5%; 0.11-25.16%; 0.30-42.32%; 2.06-37.63%, respectively, based on dry weight calculation. The high content of fatty acid in some species of microalgae showed the potential to be the feedstock of producing biofuel in overcoming the limited utilization from petroleum (fossil fuel presently.

  13. Fatty Acid Content of Indonesian Aquatic Microalgae

    Directory of Open Access Journals (Sweden)

    TRI PRARTONO

    2010-12-01

    Full Text Available High utilization of fossil fuel increases the level of carbon dioxide in the atmosphere and results in global warming phenomenon. These things establish the world’s thought to look for the other alternative energy that can reduce the use of fossil fuel even to be replaced by the substitute. Recently, Indonesia has been doing the research of microalgae as a feedstock of an alternative biofuel. Fatty acid content that microalgae have is also high to produce biofuel. The steps used in this research is a 7 days cultivation, harvesting, extraction using hexane, and fatty acid identification using Gas Chromatography of microalgae species. Fatty acid component in some species such as Chlorella sp., Scenedesmus sp., Nannochloropsis sp., and Isochrysis sp. is between 0.21-29.5%; 0.11-25.16%; 0.30-42.32%; 2.06-37.63%, respectively, based on dry weight calculation. The high content of fatty acid in some species of microalgae showed the potential to be the feedstock of producing biofuel in overcoming the limited utilization from petroleum (fossil fuel presently.

  14. Extractive and oxidative removal of copper bound to humic acid in soil.

    Science.gov (United States)

    Hwang, Bo-Ram; Kim, Eun-Jung; Yang, Jung-Seok; Baek, Kitae

    2015-04-01

    Copper (Cu) is often found strongly bound to natural organic matter (NOM) in soil through the formation of strong Cu-NOM complexes. Therefore, in order to successfully remediate Cu-contaminated soils, effective removal of Cu bound to soil organic matter should be considered. In this study, we investigated soil washing methods for Cu removal from a synthetic Cu-contaminated model silica soil coated with humic acid (HA) and from field contaminated soil. Various reagents were studied to extract Cu bound to NOM, which included oxidant (H2O2), base (NaOH), and chelating agents (citric acid and ethylenediaminetetraacetic acid (EDTA)). Among the wash reagents, EDTA extracted Cu most effectively since EDTA formed very strong complexes with Cu, and Cu-HA complexes were transformed into Cu-EDTA complexes. NaOH extracted slightly less Cu compared to EDTA. HA was effectively extracted from the model soil under strongly alkaline conditions with NaOH, which seemed to concurrently release Cu bound to HA. However, chemical oxidation with H2O2 was not effective at destroying Cu-HA complexes. Fourier transform infrared spectroscopy and elemental analysis revealed that chelating agents such as citrate and EDTA were adsorbed onto the model soil via possible complexation between HA and extraction agents. The extraction of Cu from a field contaminated soil sample was effective with chelating agents, while oxidative removal with H2O2 and extractive removal with NaOH separated negligible amounts of Cu from the soil. Based on these results, Cu bound to organic matter in soil could be effectively removed by chelating agents, although remnant agents may remain in the soil.

  15. RETENTION OF HUMIC ACID FROM WATER BY NANOFILTRATION MEMBRANE AND INFLUENCE OF SOLUTION CHEMISTRY ON MEMBRANE PERFORMANCE

    Directory of Open Access Journals (Sweden)

    M. A. Zazouli, S. Nasseri, A. H. Mahvi, M. Gholami, A. R. Mesdaghinia, M. Younesian

    2008-01-01

    Full Text Available The objectives of this research were to investigate the rejection efficiency of salt and hydrophobic fraction of natural organic matter, to study the flux decline behavior with a spiral wound nanofiltration membrane, and also to survey the influence of water chemistry on membrane performance. Experiments were conducted using a cross flow pilot-scale membrane unit with a full circulation mode. Humic acid was used as hydrophobic organic matter and NaCl as background electrolyte. Results showed that flux reduction increased with increasing ionic strength and humic acid concentration, and with lower pH. The rejection efficiency of organic and salt decreased with the decrease in pH and increase in ionic strength, because of osmotic pressure increase, leading to permeate flux decline and decrease in salt rejection. In addition, the improved salt rejection was likely due to Donnan exclusion by humic material close to membrane surfaces. The average rejection efficiency of humic acid and salt ranged between 91.2%-95.25% and 63.6%-80%, respectively. Dissolved organic carbon concentration was less than 0.57mg/L in permeate for all experiments. With increasing organic concentration, the charge of the membrane surface has become more negative due to the adsorption of organic foulants on the membrane surface, and thus increased the electrostatic repulsion. However, the increasing surface charge had the potential to result in a larger molecular weight cut-off of a fouled membrane due to membrane swelling which can lead to lower rejection solutes. Therefore, results of this study indicated that membrane fouling may significantly affect the rejection of organic and ion solute.

  16. The stabilization of tannery sludge and the character of humic acid-like during low temperature pyrolysis.

    Science.gov (United States)

    Ma, Hongrui; Gao, Mao; Hua, Li; Chao, Hao; Xu, Jing

    2015-11-01

    Tannery sludge contained plenty of organic matter, and the organic substance stability had direct impact on its derived chars' utilization. In this paper, the stabilization of tannery sludge and the variation of humic acid-like (HAL) extracted by different methods were investigated in a magnetic stirring reactor under low temperature pyrolysis of 100-400 °C. Results showed that the aromatic structure of pyrolysis chars increased with the increase of temperature and time. The char contained highly aromatic structure and relatively small dissolved organic matters (DOM) at 300 °C. The similar behaviors appeared in two HAL series by different extraction methods. The N content, H/C value, and aliphatic structures of HAL decreased with the increase of pyrolysis temperature, while the C/N value and aromatic structures increased with the rise of pyrolysis temperature. The composition and functional groups of HAL were similar with the purchased humic acid (HA). The fluorescence spectra revealed that two main peaks were found at Ex/Em = 239/363-368 nm and 283/359-368 nm in each HAL series from raw and 100 °C pyrolysis tannery sludge, representing a protein-like matter. The new peak appeared at Ex/Em = 263-283/388 nm in each HAL series from 200 °C pyrolysis tannery sludge-represented humic acid-like matter. The fluorescence intensity increased strongly compared to the other two peak intensity. Therefore, the humification of organic matter was increased by pyrolyzing. Notably, the HAL from 200 °C pyrolysis tannery sludge contained simple molecular structure, and the polycondensation increased but with a relative lower humification degree compared to soil HAL and purchased HA. Therefore, the sludge needs further oxidation. The humic substance was negligible by direct extraction when the temperature was 300 and 400 °C.

  17. Comparative sorption of benzo[alpha]phrene to different humic acids and humin in sediments.

    Science.gov (United States)

    Zhang, Jinghuan; He, Mengchang; Shi, Yehong

    2009-07-30

    Sediment/soil organic matter (SOM) is the predominant sorbents for hydrophobic organic compounds (HOCs). The identification and comparison of sorption characterization of HOCs by different organic matter fractions are essential to predict the fate and transport of HOCs in soils and sediments. The objectives of this paper are to compare the sorption of benzo[alpha]phrene (BaP) to the humic acid (HA) and humin (HM) extracted from different sediments. The HA and HM were extracted with 0.1M NaOH from five sediments in different areas in China, and their sorption isotherms for BaP were determined. All sorption isotherms were nonlinear and nonlinearity increased in the order HA

  18. Removal of metal ions and humic acids through polyetherimide membrane with grafted bentonite clay.

    Science.gov (United States)

    Hebbar, Raghavendra S; Isloor, Arun M; Prabhu, Balakrishna; Inamuddin; Asiri, Abdullah M; Ismail, A F

    2018-03-16

    Functional surfaces and polymers with branched structures have a major impact on physicochemical properties and performance of membrane materials. With the aim of greener approach for enhancement of permeation, fouling resistance and detrimental heavy metal ion rejection capacity of polyetherimide membrane, novel grafting of poly (4-styrenesulfonate) brushes on low cost, natural bentonite was carried out via distillation-precipitation polymerisation method and employed as a performance modifier. It has been demonstrated that, modified bentonite clay exhibited significant improvement in the hydrophilicity, porosity, and water uptake capacity with 3 wt. % of additive dosage. SEM and AFM analysis showed the increase in macrovoides and surface roughness with increased additive concentration. Moreover, the inclusion of modified bentonite displayed an increase in permeation rate and high anti-irreversible fouling properties with reversible fouling ratio of 75.6%. The humic acid rejection study revealed that, PEM-3 membrane having rejection efficiency up to 87.6% and foulants can be easily removed by simple hydraulic cleaning. Further, nanocomposite membranes can be significantly employed for the removal of hazardous heavy metal ions with a rejection rate of 80% and its tentative mechanism was discussed. Conspicuously, bentonite clay-bearing poly (4-styrenesulfonate) brushes are having a synergistic effect on physicochemical properties of nanocomposite membrane to enhance the performance in real field applications.

  19. Atrazine biodegradation modulated by clays and clay/humic acid complexes

    International Nuclear Information System (INIS)

    Besse-Hoggan, Pascale; Alekseeva, Tatiana; Sancelme, Martine; Delort, Anne-Marie; Forano, Claude

    2009-01-01

    The fate of pesticides in the environment is strongly related to the soil sorption processes that control not only their transfer but also their bioavailability. Cationic (Ca-bentonite) and anionic (Layered Double Hydroxide) clays behave towards the ionisable pesticide atrazine (AT) sorption with opposite tendencies: a noticeable sorption capacity for the first whereas the highly hydrophilic LDH showed no interactions with AT. These clays were modified with different humic acid (HA) contents. HA sorbed on the clay surface and increased AT interactions. The sorption effect on AT biodegradation and on its metabolite formation was studied with Pseudomonas sp. ADP. The biodegradation rate was greatly modulated by the material's sorption capacity and was clearly limited by the desorption rate. More surprisingly, it increased dramatically with LDH. Adsorption of bacterial cells on clay particles facilitates the degradation of non-sorbed chemical, and should be considered for predicting pesticide fate in the environment. - The biodegradation rate of atrazine was greatly modulated by adsorption of the pesticide and also bacterial cells on clay particles.

  20. Responses of root physiological characteristics and yield of sweet potato to humic acid urea fertilizer

    Science.gov (United States)

    Kou, Meng; Tang, Zhonghou; Zhang, Aijun; Li, Hongmin; Wei, Meng

    2017-01-01

    Humic acid (HA), not only promote the growth of crop roots, they can be combined with nitrogen (N) to increase fertilizer use efficiency and yield. However, the effects of HA urea fertilizer (HA-N) on root growth and yield of sweet potato has not been widely investigated. Xushu 28 was used as the experimental crop to investigate the effects of HA-N on root morphology, active oxygen metabolism and yield under field conditions. Results showed that nitrogen application alone was not beneficial for root growth and storage root formation during the early growth stage. HA-N significantly increased the dry weight of the root system, promoted differentiation from adventitious root to storage root, and increased the overall root activity, total root length, root diameter, root surface area, as well as root volume. HA-N thus increased the activity of superoxide dismutase (SOD), peroxidase (POD), and Catalase (CAT) as well as increasing the soluble protein content of roots and decreasing the malondialdehyde (MDA) content. HA-N significantly increased both the number of storage roots per plant increased by 14.01%, and the average fresh weight per storage root increased by 13.7%, while the yield was also obviously increased by 29.56%. In this study, HA-N increased yield through a synergistic increase of biological yield and harvest index. PMID:29253886

  1. Effect of humic acid on photocatalytic activity of ZnO nanoparticles.

    Science.gov (United States)

    Chandran, Preethy; Netha, Suhas; Sudheer Khan, S

    2014-09-05

    Zinc oxide nanoparticles (ZnO NPs) are widely used in consumer products including sunscreens, textiles and paints. The indiscriminate use of such materials may leads to its release into the environment. The present study evaluated the photocatalytic effect of ZnO NPs in presence of humic acid (HA), which is an important factor present largely in the environment. ZnO NPs were characterized by using UV-visible spectrophotometer, scanning electron microscopy, particle size analyzer and X-ray diffraction analysis. The mean diameter of the particles was found to be 55±2.1 nm. The XRD patterns exhibited hexagonal structure for ZnO NPs. The photocatalytic activity of ZnO NPs was evaluated based on the change in UV-visible absorption spectra of the methylene blue solution as a function of reaction time under visible light source. The rate of photocatalytic degradation of methylene blue was decreased with increase in HA concentration. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Responses of root physiological characteristics and yield of sweet potato to humic acid urea fertilizer.

    Directory of Open Access Journals (Sweden)

    Xiaoguang Chen

    Full Text Available Humic acid (HA, not only promote the growth of crop roots, they can be combined with nitrogen (N to increase fertilizer use efficiency and yield. However, the effects of HA urea fertilizer (HA-N on root growth and yield of sweet potato has not been widely investigated. Xushu 28 was used as the experimental crop to investigate the effects of HA-N on root morphology, active oxygen metabolism and yield under field conditions. Results showed that nitrogen application alone was not beneficial for root growth and storage root formation during the early growth stage. HA-N significantly increased the dry weight of the root system, promoted differentiation from adventitious root to storage root, and increased the overall root activity, total root length, root diameter, root surface area, as well as root volume. HA-N thus increased the activity of superoxide dismutase (SOD, peroxidase (POD, and Catalase (CAT as well as increasing the soluble protein content of roots and decreasing the malondialdehyde (MDA content. HA-N significantly increased both the number of storage roots per plant increased by 14.01%, and the average fresh weight per storage root increased by 13.7%, while the yield was also obviously increased by 29.56%. In this study, HA-N increased yield through a synergistic increase of biological yield and harvest index.

  3. Deactivation of nanoscale zero-valent iron by humic acid and by retention in water.

    Science.gov (United States)

    Kim, Do-Gun; Hwang, Yu-Hoon; Shin, Hang-Sik; Ko, Seok-Oh

    2013-01-01

    The effects of the deactivation of nanoscale zero-valent iron (NZVI), induced by humic acid (HA) and by the retention of NZVI in water, on nitrate reduction were investigated using a kinetic study. Both the nitrate removal and generation of ammonia were significantly inhibited as the HA adsorption amount and retention time were increased. However, HA removal was greatly enhanced when the NZVI was used after 1 d or 25 d of retention in water. The results are caused by the formation of iron oxides/hydroxides, which increased the specific surface area and the degree of NZVI aggregation which was observed by transmission electron microscopy (TEM). However, the nitrate reduction was greater at the beginning of reaction in the presence of HA when fresh NZVI was used, because of the enhanced electron transfer by the HA in bulk phase and on NZVI surface as train sequences. The pseudo second order adsorption kinetic equation incorporating deactivation and a Langmuir-Hinshelwood (LH) type kinetic equation provided accurate descriptions of the nitrate removal and ammonia generation, respectively. The deactivation constant and the reaction rate constant of the LH type kinetic equation were strongly correlated with the HA amount accumulated on NZVI. These results suggest that the HA accumulation on the NZVI surface reactive sites plays the dominant role in the inhibition and the inhibition can be described successfully using the deactivation model. The HA accumulation on NZVI was verified using TEM.

  4. Effect of humic acids on the metabolism of Chlorella vulgaris in a model experiment

    Science.gov (United States)

    Toropkina, M. A.; Ryumin, A. G.; Kechaikina, I. O.; Chukov, S. N.

    2017-11-01

    The effect of humic acids (HAs) on physiological processes (photosynthesis, respiration, and abundance) of green microalga Chlorella vulgaris has been studied, and the relationships between the physiological activity of HAs and their structural parameters have been investigated. It has been found that the optimum range of HA concentrations for the growth of C. vulgaris is 0.01-0.03%. In this range, the highest positive effect on total photosynthesis increment is due to hydrophilic HA preparations from fallow soddypodzolic soil (Albic Retisol) and virgin gray soil (Luvic Greyzemic Phaeozem). The minimum stimulation of respiration is noted for all HA preparations in the region of the maximum photosynthesis stimulation. At concentrations above 0.003%, all HA preparations have a negative effect: the rate of photosynthesis in C. vulgaris cells decreases, and their respiration is strongly enhanced. The abundance of C. vulgaris under the effect of all of the studied preparations under illumination increases more rapidly than in the dark. A high positive coefficient of correlation is found between the hydrophilicity of HAs calculated from 13C NMR data and the photosynthesis rate in C. vulgaris.

  5. Simultaneous Removal of Turbidity and Humic Acid Using Electrocoagulation/Flotation Process in Aqua Solution

    Directory of Open Access Journals (Sweden)

    Abdolmotaleb Seid-Mohammadi

    2015-06-01

    Full Text Available In this study, the applicability of the Electrocoagulation/Flotation (ECF process in batch operation was investigated for the simultaneous removal of turbidity and Humic acid (HA using Fe and Al electrodes. The effects of solution pH (3 - 12, electrical potentials (10 - 30 V, initial turbidity concentration (300 - 1200 NTU, and reaction time (10 - 30 minutes with or without HA were investigated in an attempt to achieve higher turbidity removal efficiency. The batch experimental results revealed that with initial turbidity of 300 NTU, at voltage of 30 V, after 30 minutes reaction times, and at pH values of 6 and 8, the ECF process for Fe and Al electrodes removed over 97% and 88% of turbidity, respectively. The percentage of turbidity removal from solution dropped with a decrease in voltages for both electrodes. The results displayed that the Fe-Fe electrode arrangement attained the highest performance for turbidity removal rate. As a result, ECF process was shown to be a very efficient, cost-effective, and promising process for efficient treatment of high turbid water. Regarding HA, the results showed that in ECF process over 67% and 43% of UV254 has been removed for Al and Fe electrodes, respectively at the optimum pH, 30 minutes reaction time and 30 V applied voltage. Thus, it can be considered that Fe and Al are the best electrodes for removing turbidity and HA, respectively.

  6. The humic acids from vermicompost protect rice (Oryza sativa L.) plants against a posterior hidric stress

    International Nuclear Information System (INIS)

    Guridi-Izquierdo, Fernando; Martínez-Balmori, Dariellys; Rosquete-Bassó, Mayelín; Calderín-García, Andrés; Louro-Berbara, Ricardo L.

    2017-01-01

    The humic acids (HA) from two different vermicompost were extracted, isolated, purified and partially characterized, to evaluate their possible protection in rice (Oryza sativa L.) plants against an hydric stress. Differences in elemental composition, as the coagulation threshold value and E4/E6 relation in their UV-Vis spectra were found. Two concentrations (40 and 60 mg L-1) of both HA were included in the nutritive solutions for rice plants in controlled conditions. It was verified that the previous treatment with the HA during six days stimulated the root biomass production. Later the HA were excluded and was an hydric deficit induced by adding polietilenglicol (PEG-6000) in the initially treated plants and in a group of those used as control. After 96 hours of this final condition the net radical biomass, the photosynthetic pigments content and the root membrane permeability were evaluated. In the plants previously treated with HA (at the concentration 60 mg HA L-1), the root membrane permeability, the net radical biomass production and the “a” chlorophyll content had no differences when compared with those without stress. It was concluded that the previous treatment with the HA protected the rice plants against a posterior hydric stress that was induced. (author)

  7. Tetracycline adsorption on kaolinite: pH, metal cations and humic acid effects.

    Science.gov (United States)

    Zhao, Yanping; Geng, Jinju; Wang, Xiaorong; Gu, Xueyuan; Gao, Shixiang

    2011-07-01

    Contamination of environmental matrixes by human and animal wastes containing antibiotics is a growing health concern. Because tetracycline is one of the most widely-used antibiotics in the world, it is important to understand the factors that influence its mobility in soils. This study investigated the effects of pH, background electrolyte cations (Li(+), Na(+), K(+), Ca(2+) and Mg(2+)), heavy metal Cu(2+) and humic acid (HA) on tetracycline adsorption onto kaolinite. Results showed that tetracycline was greatly adsorbed by kaolinite over pH 3-6, then decreased with the increase of pH, indicating that tetracycline adsorption mainly through ion exchange of cations species and complexation of zwitterions species. In the presence of five types of cations (Li(+), Na(+), K(+), Ca(2+) and Mg(2+)), tetracycline adsorption decreased in accordance with the increasing of atomic radius and valence of metal cations, which suggested that outer-sphere complexes formed between tetracycline and kaolinite, and the existence of competitor ions lead to the decreasing adsorption. The presence of Cu(2+) greatly enhanced the adsorption probably by acting as a bridge ion between tetracycline species and the edge sites of kaolinite. HA also showed a major effect on the adsorption: at pH kaolinite and need to be considered when assessing the environmental toxicity of tetracycline.

  8. Chemical and Spectroscopical Characterization of Humic Acids from two South Brazilian Coals of Different Ranks

    Directory of Open Access Journals (Sweden)

    Dick Deborah P.

    2002-01-01

    Full Text Available Humic acids (HA extracted from two coals of different ranks, from their regenerated samples and from a nitrated sample, were characterized by elemental analysis and by infra-red (FTIR, solid state 13C nuclear magnetic resonance (NMR and eletronic paramagnetic resonance (EPR spectroscopies. The low rank coal HA presented higher C and lower O contents, higher C/N and lower H/C and O/C ratios than high rank coal HA. NMR results showed that both samples were more aromatic and less carboxylic than common soil HA. Those characteristics may limit the coal HA efficiency as an appropriate soil conditioner and fertilizer. The regeneration process did not produce major alterations in the coal HA, except a decrease of the free radical content as determined by EPR spectroscopy. Probably, the regeneration conditions and time were not adequate to oxidize the samples. The obtained FTIR spectra were much alike, except that from the nitrated sample, where the absorption band at 1533 cm-1 confirms the presence of nitrated groups. The nitration process increased the N content and reduced the C/N ratio to values comparable to those reported for soil HA, but the aromaticity still remained high and the carboxylic content was lowered after the procedure.

  9. Spontaneous aggregation of humic acid observed with AFM at different pH.

    Science.gov (United States)

    Colombo, Claudio; Palumbo, Giuseppe; Angelico, Ruggero; Cho, Hyen Goo; Francioso, Ornella; Ertani, Andrea; Nardi, Serenella

    2015-11-01

    Atomic force microscopy in contact (AFM-C) mode was used to investigate the molecular dynamics of leonardite humic acid (HA) aggregate formed at different pH values. HA nanoparticles dispersed at pH values ranging from 2 to 12 were observed on a mica surface under dry conditions. The most clearly resolved and well-resulted AFM images of single particle were obtained at pH 5, where HA appeared as supramolecular particles with a conic shape and a hole in the centre. Those observations suggested that HA formed under these conditions exhibited a pseudo-amphiphilic nature, with secluded hydrophobic domains and polar subunits in direct contact with hydrophilic mica surface. Based on molecular simulation methods, a lignin-carbohydrate complex (LCC) model was proposed to explain the HA ring-like morphology. The LCC model optimized the parameters of β-O-4 linkages between 14 units of 1-4 phenyl propanoid, and resulted in an optimized structure comprising 45-50 linear helical molecules looped spirally around a central cavity. Those results added new insights on the adsorption mechanism of HA on polar surfaces as a function of pH, which was relevant from the point of view of natural aggregation in soil environment. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Interaction of indigo carmine dye with silica modified with humic acids at solid/liquid interface

    Science.gov (United States)

    Prado, Alexandre G. S.; Miranda, Bárbara S.; Jacintho, Guilherme V. M.

    2003-09-01

    Two distinct humic acids, one extracted from Brazilian peat soil, HA PS, and another one obtained from commercial source, HA FL, were attachment onto silica gel modified with aminopropyltrimethoxysilane, producing two material named SiHA PS and SiHA FL, respectively. The ability of these materials in removing indigo carmine dye from aqueous solution was followed through series of adsorption isotherms adjusted to modified Langmuir equation. The maximum number of moles adsorbed gave 6.82 ± 0.12 × 10 -4 and 2.15 ± 0.17 × 10 -4 mol g -1 for SiHA PS and SiHA FL, respectively. Same interactions were calorimetrically followed and the thermodynamic data showed endothermic enthalpic values: 12.31 ± 0.55 and 24.69 ± 1.05 kJ mol -1 for SiHA PS and SiHA FL surfaces, respectively. Gibbs free energies for two adsorption processes of indigo carmine dye presented negative values, reflecting dye/surface interactions must be accompanied by an increased in entropy values, which are 65 ± 3 and 98 ± 5 J mol -1 K -1 for SiHA PS and SiHA FL materials, respectively. The adsorption processes for both materials were spontaneous in nature although they presented an endothermic enthalpy for the interaction, resulting in an entropically favored process.

  11. The Effect of Dissolved Humic Acids on Aluminosilicate Formation and Associated Carbon Sequestration

    Directory of Open Access Journals (Sweden)

    Ashaki A. Rouff

    2012-01-01

    Full Text Available Allophane and imogolite neogenesis in soils may occur in the presence of organic matter. To understand this process under conditions relevant to soils, the influence of dissolved organic carbon (DOC as humic acid (HA, on aluminosilicate formation was studied at , pH 6, and low-DOC concentrations. For solutions with initial Al/Si ratios of 1–2.1, and 0–6 mg/L DOC, precipitates recovered after 20 h had Al/Si ratios of 2.2–2.7. The formation of allophane, imogolite-like material, and aluminosilicate gel was confirmed by XRD, FTIR, and NMR. The effect of DOC was to produce a small, but systematic increase in imogolite-like Si in the precipitate, and a decrease in the formation of aluminosilicate gel. Results suggest that the presence of DOC as HA slows the otherwise rapid polymerization of Al and Si at low temperature, and may also promote the formation of imogolite. The high C content of these precipitates indicates that this process may facilitate the sequestration of organic matter, slowing C cycling in soils.

  12. Effect of humic acid on ciprofloxacin removal by magnetic multifunctional resins

    Science.gov (United States)

    Wang, Wei; Cheng, Jiade; Jin, Jing; Zhou, Qing; Ma, Yan; Zhao, Qingqing; Li, Aimin

    2016-07-01

    Background organic matter significantly influences the removal of emerging contaminants in natural water. In this work, the adsorption of ciprofloxacin (CPX) onto a series of magnetic multifunctional resins (GMA10-GMA90) in the presence and absence of humic acid (HA) was conducted to demonstrate the effect of HA. Both hydrophobic and ion exchange interactions contributed to CPX adsorption. Negative charge-assisted hydrogen bonds also participated in the adsorption process, resulting in the high adsorption amount of anionic CPX onto the negatively charged GMA30 under basic solutions. HA could impact CPX adsorption not only as a competitive adsorbate but also as an additional adsorbent. At pH 5.6, the additional adsorption sites provided by adsorbed HA molecules on the resins dominated and thus facilitated the adsorption process. While at pH 10, HA inhibited the adsorption of CPX by directly competing for ion exchange sites and coexisting with CPX in the solution. The ratio of the amount of CPX adsorbed by dissolved HA to that by the resin reached as high as 1.61 for GMA90. The adsorbed HA molecules onto the resins could provide additional adsorption sites for CPX as proven by the enhanced CPX adsorption in HA-preloading systems at pH 5.6.

  13. The retention of calcium, barium, and strontium ions by a mollisol humic acid: Spectroscopic investigation

    Science.gov (United States)

    Oufqir, Sofia; Bloom, Paul R.; Torner, Brandy M.

    2014-05-01

    Humic substances have a major role in controlling the mobility and bioavailability of metallic ions in soils and natural waters. The alkaline earth metals, calcium, barium, and strontium, are broadly abundant in the crust of the earth, and Ca2+ ions are known to be important in the formation of structural aggregates in soils. Yet, direct spectroscopic evidence of how Ca, Ba, and Sr ions interact with soil organic matter, is minimal. To develop a deeper understanding of the interaction of the alkaline earth cations in soil, we studied the complexation behavior of strontium, barium and calcium by humic acid (HA) using solid-state 13C CP-MAS NMR, FTIR and extended x-ray absorption fine structure (EXAFS) spectroscopy. A HA sample was extracted from an agricultural mollisol (pH 6, 32.5% clay content, 3.7% organic carbon) located in southwestern Minnesota, USA, by the standard NaOH method. The HA sample was treated with chloride salts of Ca, Sr or Ba, then freeze-dried prior to spectroscopic measurements. The FTIR spectra, obtained using pressed KBr disks, and the 13C NMR spectra revealed spectral differences, stemming mainly from deprotonation reactions of the carboxylic and phenolic groups of the HA. The association of Ca, Ba, and Sr ions with the HA caused a marked FTIR shift of the carboxylate band, with the Ba shift being the most pronounced (HA 1604.7; HA-Ca 1595.1; HA-Sr 1597; HA-Ba 1579.6), which seems to imply that Ba is the strongest bound element. An NMR shift of the carbonyl peak at 171.8 ppm was also observed to 174.5 for Ca, 173.7 for Sr, and 174.4 for Ba confirming that these cations are behaving differently towards soil HA. The EXAFS spectra indicated back-scattering from oxygen atoms, in the first shell, for Ca, Sr, and Ba with varied coordination number. Our data prove that (1) the carboxylates and phenolates are the prevailing functional groups involved in the interactions between the extracted HA and alkali metal cations, (2) barium forms the

  14. Characterization of the interaction of uranyl ions with humic acids by x-ray absorption spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Reich, T.; Denecke, M.A.; Pompe, S. [Inst. of Radiochemistry, Dresden (Germany)] [and others

    1995-11-01

    Humic substances are present throughout the environment in soil and natural water. They are organic macromolecules with a variable structural formula, molecular weight, and a wide variety of functional groups depending on their origin. In natural waters, humic substances represent the main component of the {open_quotes}dissolved organic carbon{close_quotes} (DOC). The DOC may vary considerably from 1 mg/L at sea water surfaces to 50 mg/L at the surface in dark water swamps. There is strong evidence that all actinides form complexes with humic substances in natural waters. Therefore, humic substances can play an important role in the environmental migration of radionuclides by enhancing their transport. Retardation through humic substance interaction may be also possible due to formation of precipitating agglomerates. For remediation and restoration of contaminated environmental sites and risk assessment of future nuclear waste repositories, it is important to improve the predictive capabilities for radionuclide migration through a better understanding of the interaction of radionuclides with humic substances.

  15. Removal of humic acid from peat soils by using AlCl3 prior to DNA extraction

    Science.gov (United States)

    Mustafa, Irfan; Hadiatullah, Sustiyah

    2017-05-01

    The amplification of environmental DNA is one of the main steps in microbial diversity profiling of environmental samples. To represent the microbial community in the soil, DNA extraction is initially needed. The major inhibitor in the soil is a humic acid which greatly inhibits the ability of enzymes to amplify DNA. The protocol provided with the commercial kit was not able to resolve the problem. We, therefore, introduced a modification for soil sample treatment with AlCl3 as a flocculating agent that is capable of removing the humic substance contained in peat soil. This technique was superior to the original instruction for extracting DNA with the FastDNA® Spin Kit for Soil (MP Bio, USA).

  16. Humic acids and their interactions with metallic elements: Cu II, Eu III, Th IV, U VI: contribution of size exclusion chromatography method and research of complexation models

    International Nuclear Information System (INIS)

    Lesourd-Moulin, V.

    1986-04-01

    The interest given to natural organic matter (humic and fulvic acids) as complexing agents of metallic ions in soils and natural waters becomes more and more important in environmental area. Cation - humic matter interactions have a great importance, a better understanding of the contribution of these substances in natural media specially towards radioactive elements with long life time. Interactions are studied by a chromatographic technique of gel filtration: the dynamic equilibrium method is based on the separation of the formed complex humic macromolecule - metallic ion and the free metallic ion, which due to its size penetrates totally in the pores of the gel. Separation mechanisms of the chromatographic support and the contribution of each parameter, are studied as a function of the buffer nature, its concentration, the PH, the gel porosity and the valence of the metallic cation. This study led to the determination of the appropriate experimental conditions for each cation. A study of metallic binding with humic acid has been undertaken with Cu 2+ , Eu 3+ , Th 4+ , Uo 2 2+ . These elements, except copper, have been chosen for their properties similar to the transuranic elements. Different samples of humic acids (commercial, podzolic soil, rendzine soil) are also studied. A deeper research of europium - humic acid interactions by means of different treatment models (discrete or gaussian models) has been undertaken in order to determine the number, the binding site strength and the global interaction constants [fr

  17. Synthesis and utilization of chitin humic acid hybrid as sorbent for Cr(III)

    Science.gov (United States)

    Santosa, Sri Juari; Siswanta, Dwi; Sudiono, Sri; Sehol, Muhamad

    2007-11-01

    New types of hybrid material have been synthesized by using four different methods of immobilization of humic acid (HA) on chitin. The most stable hybrid material toward the change of medium acidity was then utilized as sorbent for Cr(III). The HA was extracted from peat soil of Gambut District, South Kalimantan, Indonesia, using the recommended procedure of International Humic Substances Society (IHSS), while the chitin was isolated from crab shell waste through deproteination using 3.5% (w/v) NaOH and followed by removal of inorganic impurities using 1 M HCl. The four methods of immobilization of HA on chitin were (i) Method A: chitin powder (4 g) was gently poured into the stirred solution of 0.4 g HA in 40 mL of 0.01 M NaOH. After overnight stirring, the solid was separated, washed with water, and dried in oven at 70 °C. (ii) Method B: gelatinous chitin (40 g) in 250 mL of 0.5 M HCl was reacted with HA (4 g) in 500 mL of 0.5 M NaOH and aged for 24 h. The product was washed with water and dried. (iii) Method C: HA powder (0.5 g) was mixed with the stirred gel of chitin (2.5 g) in 60 mL of CaCl 2 saturated methanol and the mixture was then washed with the mixed solution of 25 mL of 2 M sodium citrate and ethylene glycol 1:1. The solid was separated, washed with water, and dried. (iv) Method D: the solution of HA (0.056 g) in 10 mL of 0.01 M NaOH was reacted with the gel of chitin (0.2 g) in 10 mL of CaCl 2 saturated methanol. After 24 h stirring, the solid was separated from the reaction medium, washed with the mixed solution of 2 M sodium citrate and ethylene glycol 1:1, and followed by washing with water and drying. Parameters investigated in this study consisted of the stability test of the immobilized HA, as well as the rate constant ( k1), capacity ( b), and energy ( E) of sorption as well as the rate constant of desorption ( k-1). The k1 and k-1 were determined according to a kinetic model of first order sorption reaching equilibrium, while the b and E

  18. Humic Acid Degradation via Solar Photo-Fenton Process in Aqueous Environment

    Directory of Open Access Journals (Sweden)

    Seyed Ali Sajjadi

    2015-08-01

    Full Text Available Control of mutagenic and carcinogenic disinfection by-products, particularly Trihalomethanes (THMs and Halo Acetic Acids (HAAs in water treatment process is critical, due to their adverse effects on human health. Generally, reducing the toxicity of these by-products hinges on prior removal of the precursor materials, such as Humic Acid (HA in drinking water. This study was conducted to investigate the role of some parameters that could affect the removal of HA, including HA (5 and 10 ppm and H2O2 (20, 40, 60, and 80 ppm initial concentrations, Iron (II, sulfate heptahydrate dosage (4, 8, 12, and 16 ppm, pH (2, 3, 4 and 5, Oxidation time (5, 10, 15 and 30 min, and Sunlight levels (322±13 kWm-2. To accelerate the process of HA removal, the Solar Photo-Fenton (SPF process was employed by direct irradiation of converged sunlight in a Parabolic Trough Collectors (PTC, with 3m2 effective area. HA levels were measured via quantifying Dissolved Organic Carbon (DOC concentrations by means of a TOC Analyzer method. The results showed that the SPF process is under control of the Fe & H2O2 ratio, the Fe2+ dosage and especially the pH quantity. In optimal condition, (pH: 4, oxidation time: 30min, initial HA levels: 50 ppm, H2O2 concentrations: 20 ppm Fe+2 levels: 4 ppm, the study found more than 98% DOC removal. In conclusion, the SPF, as an economically effective technique, could be applied for the removal of HA in aqueous environments.

  19. Effect of the use and the cover of the soil on the profile of polydispersity of humic acids extracted of an andisol from the department of Caldas, Colombia

    International Nuclear Information System (INIS)

    Avellaneda, Lizeth Manuela; Lozano de Yunda, Amanda; Zamudio, Adriana Mireya

    2005-01-01

    In order to know the possible effect of the use and the cover of soil, on the polydispersity profile of humic acids were analyzed the a horizon of three samples of an andisol (melanudand) from the department of Caldas, Colombia, that have presented different management and coverland as soils under forest of bamboo, coffee with somber of Guamo and under free exposition coffee. For this in the lower fraction to 50 μm, the sequential extraction of humic substances was carried out with solutions of sodium tetraborate (Na2B 4 O7 0.05 m), sodium pyrophosphate (Na4P 2 O7 0.025 m) and sodium hydroxide (NaOH 0.1m) and the later separation and purification of the respective humic acids. To obtain the polydispersity profiles were applied the exclusion chromatography separation by size technique utilizing sephadex g-75 and ultra centrifugation by gradient of density with sucrose and they devised graphics of distribution by size (absorbance (450 nm) vs. volume eluted). It was found that the humic acids extracted with sodium hydroxide presented smaller polydispersity, bigger size and molecular weight, as well as, degree of aromatic condensation. The results did not show drastic effect of the use and the cover land, on the polydispersity profile and the coefficient of sedimentation of the humic acids, which is related to the size, weight and molecular density of the same ones. Nevertheless, it was found that the humic acids of the samples of soil under coffee with somber of Guamo and free exposition coffee are very similar among it and different from the sample under forest of bamboo. This fact was associated with a beginning of the effect of the use and the cover of the soil on the size of the humic acids. It presumed that in the long term the effect is accentuated and eventually could be considered as indicator of degradation of the organic component of the soil

  20. A comparison between alkaline and decomplexing reagents to extract humic acids from low rank coals

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, D.; Cegarra, J.; Abad, M. [CSIC, Madrid (Spain). Centro de Edafologia y Biologia Aplicada del Segura

    1996-07-01

    Humic acids (HAs) were obtained from two low rank coals (lignite and leonardite) by using either alkali extractants (0.1 M NaOH, 0.1 M KOH or 0.25 M KOH) or solutions containing Na{sub 4}P{sub 2}O{sub 7} (0.1 M Na{sub 4}P{sub 2}O{sub 7} or 0.1 M NaOH/Na{sub 4}P{sub 2}O{sub 7}). In both coals, the greatest yields were obtained with 0.25 M KOH and the lowest with the 0.1 M alkalis, whereas the extractions based on Na{sub 4}P{sub 2}O{sub 7} yielded intermediate values and were more effective on the lignite. Chemical analysis showed that the leonardite HAs consisted of molecules that were less oxidized and had fewer functional groups than the HAs released form the lignite. Moreover, the HAs extracted by reagents containing Na{sub 4}P{sub 2}O{sub 7} exhibited more functional groups than those extracted with alkali, this effect being more apparent in lignite because of its greater cation exchange capacity. Gel permeation chromatography indicated that the leonardite HAs contained a greater proportion of higher molecular size compounds than the lignite HAs, and that both solutions containing Na{sub 4}P{sub 2}O{sub 7} released HAs with a greater proportion of smaller molecular compounds from the lignite than did the alkali extractants. 16 refs., 3 figs., 2 tabs.

  1. Transformation of Flame Retardant Tetrabromobisphenol A by Aqueous Chlorine and the Effect of Humic Acid.

    Science.gov (United States)

    Gao, Yuan; Pang, Su-Yan; Jiang, Jin; Ma, Jun; Zhou, Yang; Li, Juan; Wang, Li-Hong; Lu, Xue-Ting; Yuan, Li-Peng

    2016-09-06

    In this work, it was found that the most widely used brominated flame retardant tetrabromobisphenol A (TBrBPA) could be transformed by free chlorine over a wide pH range from 5 to 10 with apparent second-order rate constants from 138 to 3210 M(-1)·s(-1). A total of eight products, including one quinone-like compound (i.e., 2,6-dibromoquinone), two dimers, and several simple halogenated phenols (e.g., 4-(2-hydroxyisopropyl)-2,6-dibromophenol, 2,6-dibromohydroquinone, and 2,4,6-tribromophenol), were detected by high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) using a novel precursor ion scan (PIS) approach. A tentative reaction pathway was proposed: chlorine initially oxidized TBrBPA leading to the formation of a phenoxy radical, and then this primary radical and its secondary intermediates (e.g., 2,6-dibromo-4-isopropylphenol carbocation) formed via beta-scission subsequently underwent substitution, dimerization, and oxidation reactions. Humic acid (HA) considerably inhibited the degradation rates of TBrBPA by chlorine even accounting for oxidant consumption. A similar inhibitory effect of HA was also observed in permanganate and ferrate oxidation. This inhibitory effect was possibly attributed to the fact that HA competitively reacted with the phenoxy radical of TBrBPA and reversed it back to parent TBrBPA. This study confirms that chlorine can transform phenolic compounds (e.g., TBrBPA) via electron transfer rather than the well-documented electrophilic substitution, which also have implications on the formation pathway of halo-benzoquinones during chlorine disinfection. These findings can improve the understanding of chlorine chemistry in water and wastewater treatment.

  2. Impact of humic acid on the degradation of levofloxacin by aqueous permanganate: Kinetics and mechanism.

    Science.gov (United States)

    Xu, Ke; Ben, Weiwei; Ling, Wencui; Zhang, Yu; Qu, Jiuhui; Qiang, Zhimin

    2017-10-15

    Levofloxacin (LF) is a frequently detected fluoroquinolone in surface water, and permanganate (MnO 4 - ) is a commonly used oxidant in drinking water treatment. This study investigated the impact of humic acid (HA) on LF degradation by aqueous MnO 4 - from both kinetic and mechanistic aspects. In the absence of HA, the second-order rate constant (k) of LF degradation by MnO 4 - was determined to be 3.9 M -1  s -1 at pH 7.5, which increased with decreasing pH. In the presence of HA, the pseudo-first-order rate constant (k obs ) of LF degradation at pH 7.5 was significantly increased by 3.8- and 2.8-fold at [HA] o :[KMnO 4 ] o (mass ratio) = 0.5 and 1, respectively. Secondary oxidant scavenging and electron paramagnetic resonance tests indicated that HA could form a complex with Mn(III), a strongly oxidative intermediate produced in the reaction of MnO 4 - with HA, to induce the successive formation of superoxide radicals (O 2 - ) and hydroxyl radicals (OH). The resulting OH primarily contributed to the accelerated LF degradation, and the complex [HA-Mn(III)] could account for the rest of acceleration. The degradation of LF and its byproducts during MnO 4 - oxidation was mainly through hydroxylation, dehydrogenation and carboxylation, and the presence of HA led to a stronger destruction of LF. This study helps better understand the degradation of organic micropollutants by MnO 4 - in drinking water treatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Clay filter-aid in ultrafiltration (UF) of humic acid solution

    KAUST Repository

    Pontié, M.

    2012-04-01

    Fouling studies with three different molecular weight cut-off (MWCO) (100. kDa, 30. kDa and 10. kDa) membranes in regenerated cellulose were carried out in the presence of Acros humic acids (HA) at pH 3.0, 6.7 and 9.5. It was shown that the tighter membranes were less fouled compared with the higher MWCO membranes. 100. kDa membrane showed the highest degree of fouling. The role of pH showed that the highest degree of fouling happened at a neutral pH (pH 6.7) and the lowest degree of fouling happened at a basic pH (pH 9.5).Effectiveness of a novel pre-treatment method was applied to the 100kDa membrane. We added in the HA solution clay particles, homemade synthetized from natural bentonite and denoted Mont-CTAB. We observed a gain in productivity of 25%. 2D-fractal dimension parameter decreased under 1.5, showing a de-organization of the cake due to clay particles in/on the cake and a specific resistance of 4.4×10 11m/kg was obtained in presence of clays versus 3.6×10 14m/kg with HA alone. Finally the development of clay assisted ultrafiltration process changes the cake morphology limiting fouling impact and it is hope that for long term experiments, formation of a gel-layer should be limited. © 2012 Elsevier B.V..

  4. Humic acid-induced silver nanoparticle formation under environmentally relevant conditions.

    Science.gov (United States)

    Akaighe, Nelson; Maccuspie, Robert I; Navarro, Divina A; Aga, Diana S; Banerjee, Sarbajit; Sohn, Mary; Sharma, Virender K

    2011-05-01

    The formation of silver nanoparticles (AgNPs) via reduction of silver ions (Ag(+)) in the presence of humic acids (HAs) under various environmentally relevant conditions is described. HAs tested originated from the Suwannee River (SUW), and included samples of three sedimentary HAs (SHAs), and five soils obtained across the state of Florida. The time required to form AgNPs varied depending upon the type and concentration of HA, as well as temperature. SUW and all three SHAs reduced Ag(+) at 22 °C. However, none of the soil HAs formed absorbance-detectable AgNPs at room temperature when allowed to react for a period of 25 days, at which time experiments were halted. The appearance of the characteristic surface plasmon resonance (SPR) of AgNPs was observed by ultraviolet-visible spectroscopy in as few as 2-4 days at 22 °C for SHAs and SUW. An elevated temperature of 90 °C resulted in the accelerated appearance of the SPR within 90 min for SUW and all SHAs. The formation of AgNPs at 90 °C was usually complete within 3 h. Transmission electron microscopy and atomic force microscopy images showed that the AgNPs formed were typically spherical and had a broad size distribution. Dynamic light scattering also revealed polydisperse particle size distributions. HAs appeared to colloidally stabilize AgNPs based on lack of any significant change in the spectral characteristics over a period of two months. The results suggest the potential for direct formation of AgNPs under environmental conditions from Ag(+) sources, implying that not all AgNPs observed in natural waters today may be of anthropogenic origin.

  5. Transformation of triclosan by laccase catalyzed oxidation: The influence of humic acid-metal binding process.

    Science.gov (United States)

    Lu, Junhe; Shi, Yuanyuan; Ji, Yuefei; Kong, Deyang; Huang, Qingguo

    2017-01-01

    Laccase is a widely present extracellular phenoloxidase excreted by fungi, bacteria, and high plants. It is able to catalyze one-electron oxidation of phenolic compounds into radical intermediates that can subsequently couple to each other via covalent bonds. These reactions are believed to play an important role in humification process and the transformation of contaminants containing phenolic functionalities in the environment. In this study, we investigated the kinetics of triclosan transformation catalyzed by laccase. It was found that the rate of triclosan oxidation was first order to the concentrations of both substrate and enzyme. Humic acid (HA) could inhibit the reaction by quenching the radical intermediate of triclosan generated by laccase oxidation. Such inhibition was more significant in the presence of divalent metal cations. This is because that binding to metal ions neutralized the negative charge of HA molecules, thus making them more accessible to laccase molecule that is also negatively charged. Therefore, it has greater chance to quench the radical intermediate that is very unstable and can only diffuse a limited distance after being released from the enzyme catalytic center. Based on these understandings, a reaction model was developed by integration of metal-HA binding equilibriums and kinetic equations. This model precisely predicted the transformation rate of triclosan in the presence of HA and divalent metal ions including Ca 2+ , Mg 2+ , Cd 2+ , Co 2+ , Mn 2+ , Ba 2+ , and Zn 2+ . Overall, this work reveals important insights into laccase catalyzed oxidative coupling process. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Antagonistic effect of humic acid and naphthalene on biochar colloid transport in saturated porous media.

    Science.gov (United States)

    Yang, Wen; Wang, Yang; Shang, Jianying; Liu, Kesi; Sharma, Prabhakar; Liu, Juan; Li, Baoguo

    2017-12-01

    Biochar is a carbon-enriched material derived from organic material pyrolysis under no/limited oxygen, which is widely used for soil amendment, carbon sequestration, and contaminated soil remediation. This study aims to explore the interplay effect of humic acid (HA) and naphthalene on transport of biochar colloid (BC) in saturated porous media. A series of column experiments were conducted to study BC mobility at different concentrations of HA (0, 10, and 20 mg L -1 ) and naphthalene (0, 0.1, and 0.2 mg L -1 ). The results showed that increasing HA concentration promoted BCs mobility in porous media by increasing the electrostatic and steric interaction between BCs and collectors. However, the presence of naphthalene reduced the mobility of BCs with naphthalene increasing from 0 to 0.2 mg L -1 , because the nonpolar naphthalene adsorbed onto the biochar surface and shielded the negative charge of BCs. The maximum breakthrough C/C 0 of BCs was increased from 0.7 to 0.8 with increasing HA concentration from 0 to 20 mg L -1 in the presence of 0.1 mg L -1 naphthalene. This meant that HA still played the role to increase the electrostatic repulsion between BCs with HA and collectors when naphthalene was adsorbed on BCs. BCs breakthrough curves were well described by the two-site kinetic retention model including one reversible retention site and another irreversible retention site. The antagonistic effects of naphthalene and HA on BC transport suggested that the mobility of colloidal biochar particles in naphthalene-polluted soil was dependent on the coupled effects of naphthalene and natural organic matter. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Effect of humic acid preloading on phosphate adsorption onto zirconium-modified zeolite.

    Science.gov (United States)

    Lin, Jianwei; Zhang, Zhe; Zhan, Yanhui

    2017-05-01

    A zirconium-modified zeolite (ZrMZ) was prepared, and then, humic acid (HA) was immobilized on the ZrMZ surface to prepare HA-loaded ZrMZ (HA-ZrMZ). The obtained ZrMZ and HA-ZrMZ were characterized by energy dispersive X-ray spectroscopy, elemental analyzer, N 2 adsorption/desorption isotherms, pH at the point of zero charge, and X-ray photoelectron spectroscopy. The adsorption characteristics of phosphate on ZrMZ and HA-ZrMZ were comparatively investigated in batch mode. The adsorption mechanism of phosphate on ZrMZ and HA-ZrMZ was investigated by ionic strength effect and 31 P nuclear magnetic resonance. The mechanism for phosphate adsorption onto ZrMZ was the formation of inner-sphere phosphate complexes at the solid/solution interface. The preloading of HA on ZrMZ reduced the phosphate adsorption capacity, and the more the HA loading amount, the lower the phosphate adsorption capacity. However, the preloading of HA on ZrMZ did not change the phosphate adsorption mechanism; i.e., the formation of inner-sphere phosphate surface complexes was still responsible for the adsorption of phosphate on HA-ZrMZ. The decreased phosphate adsorption capacity for ZrMZ after HA coating could be attributed to the fact that the coating of HA on ZrMZ reduced the amount of binding active sites available for phosphate adsorption, changed the adsorbent surface charges, and reduced the specific surface areas and pore volumes of ZrMZ.

  8. Removal of humic acid from aqueous solution by magnetically separable polyaniline: adsorption behavior and mechanism.

    Science.gov (United States)

    Wang, Jiahong; Bi, Lijuan; Ji, Yanfen; Ma, Hongrui; Yin, Xiaolong

    2014-09-15

    Magnetically separable polyaniline (Fe3O4@SiO2-PANI) was prepared by in situ chemical polymerization of aniline on the surface of silica-coated Fe3O4 nanoparticles, and characterized by FTIR spectroscopy, powder X-ray diffraction, elemental analysis, transmission electron microscopy, vibrating sample magnetometry and X-ray photoelectron spectroscopy. Characterization results showed that Fe3O4@SiO2-PANI with amino groups of 1.78 mmol/g and the average diameter of 21.6 nm are superparamagnetic. Adsorption behavior of Fe3O4@SiO2-PANI nanoparticles for humic acid (HA) was investigated by batch experiments and adsorption kinetic tests. HA adsorption amount on the adsorbent decreased with increasing solution pH and the presence of Ca(2+) resulted in the enhanced HA adsorption. HA adsorption on Fe3O4@SiO2-PANI could be well described by Langmuir model and the maximum adsorption amount of the adsorbent for HA at 25°C was 36.36 mg/g. HA adsorption process on the adsorbent obey pseudo-second-order kinetics and the adsorption rates decrease with increasing initial HA concentration. The XPS analysis verified that HA adsorption over the adsorbent could be attributed to the surface complexation between the disassociated HA molecules and the protonated nitrogen of polyaniline on the adsorbent. HA loaded adsorbent could be magnetically separated and easily desorbed in 0.01 mol/L NaOH solution. Regeneration tests indicated that Fe3O4@SiO2-PANI could be used repeatedly. Copyright © 2014 Elsevier Inc. All rights reserved.

  9. The cowpea (Vigna unguiculata L. Walp and its response to the application of humic acids (HA´s in Canton Jipijapa in Ecuador

    Directory of Open Access Journals (Sweden)

    Ayón Fernando

    2017-05-01

    Full Text Available This research was carried out in the Jipijapa canton, Manabi province of Ecuador, with the following objectives: i to identify the dose of humic acid in the caupí crop, ii to determine the time for foliar application of humic acid, and iii determine the marginal rate of return in terms of cost/benefit. A plot in experimental design of completely randomized blocks (DCRB with factorial arrangement of 4 x 3 with four replications was implemented. The variables plant height (PH, stem diameter (SD, sheath length (SL, number of decks (ND and average weight of decks (AWD were evaluated. The results showed that to improve cowpea production, the addition of significant amounts of iron is required. The dose of leaf application was 1000 cm3/ha of humic acids, the PH was 48.76 cm and SD of 9.66 mm. The time for foliar application of humic acids was at 30 days, the length of pod was obtained with 21.16 cm and numbers of decks with 14.34. For the weight of the mallets, the treatment was the application to the 15 days after the sowing. There was a high and significant correlation between PH and SD (0.54. When the economic analysis was carried out, the T8 treatment, 1000 cm3/ha of humic acid was applied, applied 30 days after sowing was the one with the marginal return rate with 271.43%.

  10. The effect of phytobiotics, organic acids and humic acids on the utility and egg quality of laying hens

    Directory of Open Access Journals (Sweden)

    Henrieta Arpášová

    2017-11-01

    Full Text Available The aim of this study was the assessment of an influence of supplement of dietary herbal additive in combination with organic acids into feed mixture or drinking water of laying hens on performance parameters and egg quality. The Lohmann Brown Lite laying hens (n = 30 were divided into 3 groups (n = 10, and fed for 20 weeks ad libitum with complete feed mixtures (CFM. Hens in the control group received the complete feed mixture (CFM and drank drinking water without any supplements. In the first experimental group hens received CFM without supplements but phytobiotics (bergamot oil (Citrus bergamia, thyme (Thymus vulgaris, clove (Syzygium aromaticum, pepper (Piper nigrum in combination with the fumaric acid and citric acid at 60 mg per 1 liter of water were added to their drinking water. In the second experimental group was CFM enriched with humic acids in the concentration of 0.5%, and phytobiotcs with organic acids at the same dose as in the first experimental group were added to their drinking water. Monitored parameters: body weight (g, egg production (%, the weight of all produced eggs (g, egg albumen weight (g, egg albumen index, Haugh unit (HU, egg yolk weight (g, egg yolk index, egg yolk colour (° HLR, egg shell weight (g and egg shell strength (N.cm-2. The results showed no significant differences between the both experimental groups and the control group in the parameter body weight of hens (P>0.05. The highest average body weight was found in the hens from the second experimental group (values in the order of groups:  1792.22 ± 80.85; 1768.42 ±55.55; 1820.12 ±78.56 g±S.D.. We observed positive trend of increasing of egg production by adding of used supplements, especially in the second experimental group with the addition of humic acids, although with no statistically significant difference compared to the control group (P>0.05. The mean laying intensity in the order of groups: 90.42; 91.16; 91.56%. We observed statistically

  11. Molybdenum (VI) binded to humic and nitrohumic acid models in aqueous solutions salicylic, 3-nitrosalicylic, 5-nitrosalicylic and 3,5 dinitrosalicylic acids, Part 2

    International Nuclear Information System (INIS)

    Merce, Ana Lucia R.; Lopes, Priscilla P.; Mangricha, Antonio S.

    2006-01-01

    In this work electrochemical and Ultraviolet-Visible studies were performed in solutions of salicylic acid models of humic and nitrohumic acids, a laboratory artifact, and molybdenum in order to determine the affinity of these models towards the metal ion. Molybdenum, which plays a very important role in the soil chemistry, and together with humic substances, impart fertility to soil and water and is a key element in the activity of nitrogenase. The obtained results showed that at least one complexed species is present at the pH range of 6.3 to 8.0, even for the less basic chosen models, the nitrosalicylic acids. Previous study showed that phthalic and nitrophthalic, also humic and nitrohumic acids model compounds, presented complexed species with molybdenum only till pH 6.5. The calculated formation constants showed that the substitution of the nitro group in the orto position was less favoured than in the para substitution, probably due to a steric hindrance in the former, which was clearly seen in the double substituted salicylic nitro derivative. The cyclic voltammetry as well as the Ultraviolet-Visible obtained spectra were able to show that the chemistry of molybdenum in aqueous solutions as the pH is increased is very complex, and the molybdate stops acting as an anion only after pH around 4, when it finally becomes a cation MoO 2 2+ (M). (author)

  12. Molybdenum (VI binded to humic and nitrohumic acid models in aqueous solutions. Salicylic, 3-nitrosalicylic, 5-nitrosalicylic and 3,5 dinitrosalicylic acids: part 2

    Directory of Open Access Journals (Sweden)

    Mercê Ana Lucia R.

    2006-01-01

    Full Text Available In this work electrochemical and Ultraviolet-Visible studies were performed in solutions of salicylic acid models of humic and nitrohumic acids, a laboratory artifact, and molybdenum in order to determine the affinity of these models towards the metal ion. Molybdenum, which plays a very important role in the soil chemistry, and together with humic substances, impart fertility to soil and water and is a key element in the activity of nitrogenase. The obtained results showed that at least one complexed species is present at the pH range of 6.3 to 8.0, even for the less basic chosen models, the nitrosalicylic acids. Previous study showed that phthalic and nitrophthalic, also humic and nitrohumic acids model compounds, presented complexed species with molybdenum only till pH 6.5. The calculated formation constants showed that the substitution of the nitro group in the orto position was less favoured than in the para substitution, probably due to a steric hindrance in the former, which was clearly seen in the double substituted salicylic nitro derivative. The cyclic voltammetry as well as the Ultraviolet-Visible obtained spectra were able to show that the chemistry of molybdenum in aqueous solutions as the pH is increased is very complex, and the molybdate stops acting as an anion only after pH around 4, when it finally becomes a cation MoO2(2+ (M.

  13. Advanced oxidation treatment and photochemical fate of selected antidepressant pharmaceuticals in solutions of Suwannee River humic acid

    International Nuclear Information System (INIS)

    Santoke, Hanoz; Song, Weihua; Cooper, William J.; Peake, Barrie M.

    2012-01-01

    Highlights: ► We elucidate the photochemical degradation of three antidepressant pharmaceuticals. ► Hydroxyl radical is the most significant contributor to the degradation. ► Excited state dissolved organic matter also plays a significant role for duloxetine. ► Tentative reaction byproducts are identified. - Abstract: Antidepressant pharmaceuticals have recently been detected at low concentrations in wastewater and surface water. This work reports studies of the direct and indirect photochemical fate and treatment by advanced oxidation of three antidepressant compounds (duloxetine, venlafaxine and bupropion) in solutions of humic acid in order to elucidate their behavior in the natural environment prior to reaching a water treatment facility and potentially entering a potable water supply. Humic acid solution was prepared by adding to distilled water a known amount of organic matter as a photosensitizer. All three antidepressants react very rapidly with hydroxyl radicals (·OH) and hydrated electrons (e − aq ) with rate constants of ∼10 8 to 10 10 M −1 s −1 , but significantly slower with singlet oxygen ( 1 ΔO 2 ) (∼10 3 to 10 5 M −1 s −1 ). The steady-state concentrations of ·OH and 1 ΔO 2 , in a sample of humic acid solution were measured and used with the second order rate constants to show that the hydroxyl radical was an order of magnitude more effective than the singlet oxygen in the solar-induced photochemical degradation of the antidepressants. Excited state dissolved organic matter also accounted for a substantial portion of degradation of duloxetine, decreasing its half-life by 27% under solar irradiation. Several reaction pathways and by-products arising from the photodegradation were identified using gamma-irradiation followed by LC–MS analysis.

  14. Advanced oxidation treatment and photochemical fate of selected antidepressant pharmaceuticals in solutions of Suwannee River humic acid

    Energy Technology Data Exchange (ETDEWEB)

    Santoke, Hanoz, E-mail: hsantoke@uci.edu [Urban Water Research Center, Department of Civil and Environmental Engineering, University of California, Irvine, Irvine, CA 92697-2175 (United States); Song, Weihua, E-mail: wsong@uci.edu [Urban Water Research Center, Department of Civil and Environmental Engineering, University of California, Irvine, Irvine, CA 92697-2175 (United States); Department of Environmental Science and Engineering, Fudan University, Shanghai, 200433 (China); Cooper, William J., E-mail: wcooper@uci.edu [Urban Water Research Center, Department of Civil and Environmental Engineering, University of California, Irvine, Irvine, CA 92697-2175 (United States); Peake, Barrie M., E-mail: bpeake@chemistry.otago.ac.nz [Chemistry Department, University of Otago, P.O. Box 56, Dunedin 9054 (New Zealand)

    2012-05-30

    Highlights: Black-Right-Pointing-Pointer We elucidate the photochemical degradation of three antidepressant pharmaceuticals. Black-Right-Pointing-Pointer Hydroxyl radical is the most significant contributor to the degradation. Black-Right-Pointing-Pointer Excited state dissolved organic matter also plays a significant role for duloxetine. Black-Right-Pointing-Pointer Tentative reaction byproducts are identified. - Abstract: Antidepressant pharmaceuticals have recently been detected at low concentrations in wastewater and surface water. This work reports studies of the direct and indirect photochemical fate and treatment by advanced oxidation of three antidepressant compounds (duloxetine, venlafaxine and bupropion) in solutions of humic acid in order to elucidate their behavior in the natural environment prior to reaching a water treatment facility and potentially entering a potable water supply. Humic acid solution was prepared by adding to distilled water a known amount of organic matter as a photosensitizer. All three antidepressants react very rapidly with hydroxyl radicals ({center_dot}OH) and hydrated electrons (e{sup -}{sub aq}) with rate constants of {approx}10{sup 8} to 10{sup 10} M{sup -1} s{sup -1}, but significantly slower with singlet oxygen ({sup 1}{Delta}O{sub 2}) ({approx}10{sup 3} to 10{sup 5} M{sup -1} s{sup -1}). The steady-state concentrations of {center_dot}OH and {sup 1}{Delta}O{sub 2}, in a sample of humic acid solution were measured and used with the second order rate constants to show that the hydroxyl radical was an order of magnitude more effective than the singlet oxygen in the solar-induced photochemical degradation of the antidepressants. Excited state dissolved organic matter also accounted for a substantial portion of degradation of duloxetine, decreasing its half-life by 27% under solar irradiation. Several reaction pathways and by-products arising from the photodegradation were identified using gamma-irradiation followed by LC

  15. Effects of Humic Acid and Suspended Solids on the Removal of Heavy Metals from Water by Adsorption onto Granular Activated Carbon

    Directory of Open Access Journals (Sweden)

    Danious P. Sounthararajah

    2015-08-01

    Full Text Available Heavy metals constitute some of the most dangerous pollutants of water, as they are toxic to humans, animals, and aquatic organisms. These metals are considered to be of major public health concern and, therefore, need to be removed. Adsorption is a common physico-chemical process used to remove heavy metals. Dissolved organic carbon (DOC and suspended solids (SS are associated pollutants in water systems that can interact with heavy metals during the treatment process. The interactions of DOC and SS during the removal of heavy metals by granular activated carbon were investigated in batch and fixed-bed column experiments. Batch adsorption studies indicated that Langmuir adsorption maxima for Pb, Cu, Zn, Cd, and Ni at pH 6.5 were 11.9, 11.8, 3.3, 2.0, and 1.8 mg/g, respectively. With the addition of humic acid (HA (DOC representative, they were 7.5, 3.7, 3.2, 1.6, and 2.5 mg/g, respectively. In the column experiment, no breakthrough (complete removal was obtained for Pb and Cu, but adding HA provided a breakthrough in removing these metals. For Zn, Cd and Ni, this breakthrough occurred even without HA being added. Adding kaolinite (representative of SS had no effect on Pb and Cu, but it did on the other metals.

  16. Measurement of humic and fulvic acid concentrations and dissolution properties by a rapid batch procedure.

    NARCIS (Netherlands)

    Zomeren, van A.; Comans, R.N.J.

    2007-01-01

    Although humic substances (HS) strongly facilitate the transport of metals and hydrophobic organic contaminants in environmental systems, their measurement is hampered by the time-consuming nature of currently available methods for their isolation and purification. We present and apply a new rapid

  17. Effects of organic wastes on structural characterizations of humic acid in semiarid soil under plastic mulched drip irrigation.

    Science.gov (United States)

    Hu, Juan; Wu, Jinggui; Qu, Xiaojing; Li, Jianming

    2018-02-22

    The objective of this work was to evaluate the variation in the amount and structure of humic acid (HA) after the application of organic wastes (OWs) in semiarid soil under plastic mulched drip irrigation, measured by elemental composition, excitation-emission matrix (EEM) fluorescence, and carbon 13 nuclear magnetic resonance ( 13 C CPMAS NMR). The experiment involved chemical fertilizer combined with chicken manure (CM), sheep manure (SM), maize straw (MS), fodder grass (FG), and tree leaves (TL), while chemical fertilizer only was used as control (CK). The highest cation exchange capacity (CEC), soil organic carbon (SOC), and HA contents (P plastic mulched drip irrigation conditions. Copyright © 2018 Elsevier Ltd. All rights reserved.

  18. Effect of Potassium Sulphate and Humic acid on Growth, Yield and Essential Oil Content in Hypericum perforatum L.

    Directory of Open Access Journals (Sweden)

    H. Kaboli Farshchi

    2016-07-01

    Full Text Available Introduction: Medicinal and aromatic plants can play an important role in commercial crops, which also represent a safe alternative for chemical pharmaceutical industries. St. John’s Wort (Hypericum perforatum L. due to its therapeutic efficacy has been used for decades in folk medicine and is considered as a promising medicinal plant with valuable potential as a source of hypericin, essential oils and antioxidants. Studies on agronomic factors such as application of potassium and humic acid as well as nitrogen fertilization on yield, essential oil and antioxidant activity of Hypericum perforatum have not been investigated thoroughly until now. This study was designed to study the effect of using humic acid and potassium sulphate on morphological and phytochemical characteristics of Hypericum perforatum. Materials and Methods: The plant material was prepared from Science and Technology Park in Khorasan-e Razzavi–Mashhad. In spring, the plants were transplanted into the field of Horticulture department, Ferdowsi University of Mashhad, for fertilizing treatments. The experimental layout was factorial in a complete randomized design (CRD, with three replications. Potassium Sulphate (K2SO4 was applied at the rates of 0.0 (K0, 60 (K60 and 100 (K100 kg ha-1. The other treatment were humic acid, which was applied at three rates 0 (H0, 20 (H20 and 40 (H40 L ha-1. Plants were treated at two stages, before flowering by potassium fertilizer and fertigated four times in 15-day intervals with humic acid. Besides the fresh and dry weight, number of flowers, stem height and number of flowering stems were determined at the end of the growing stage. Results and Discussion: The ANOVA indicated that most of measured attributes of Hypericum perforatum plant were significantly affected by both treatments. Data presented revealed that the highest stem (91.6 cm was recorded at the highest level of potassium sulphate (K100 treatment, while the shortest height (60

  19. Fluorescence of soil humic acids and their fractions obtained by tandem size exclusion chromatography-polyacrylamide gel electrophoresis

    Energy Technology Data Exchange (ETDEWEB)

    Trubetskaya, O. [Russian Academy of Sciences, Moscow Region (Russian Federation). Shemyakin and Ovchinnikov Inst. of Bioorganic Chemistry; Trubetskoj, O. [Russian Academy of Sciences, Moscow Region (Russian Federation). Inst. of Basic Biological Problems; Guyot, G.; Richard, C. [UMR CNRS 6505, Aubiere (France). Lab. de Photochimie Moleculaire et Macromoleculaire; Andreux, F. [Centre des Sciences de la Terre, Dijon (France)

    2002-07-01

    Humic acids (HAs) extracted from soils of different origin (chernozem, ferralsol and ranker) and their fractions (A, B and C+D) obtained by tandem size exclusion chromatography-polyacrylamide gel electrophoresis were investigated by steady-state fluorescence spectroscopy in the emission mode. Independently of HA source, high molecular size fractions A and B are shown to be weakly fluorescent. The main fluorophores, especially those emitting at long wavelength (around 500-510 nm), are contained in the polar and low molecular size fractions C+D. As indicated by the observed pH effect, aromatic structures bearing carboxylate and OH substituents may be involved in these longer wavelength emissions. [author].

  20. Immobilization of metal-humic acid complexes in anaerobic granular sludge for their application as solid-phase redox mediators in the biotransformation of iopromide in UASB reactors.

    Science.gov (United States)

    Cruz-Zavala, Aracely S; Pat-Espadas, Aurora M; Rangel-Mendez, J Rene; Chazaro-Ruiz, Luis F; Ascacio-Valdes, Juan A; Aguilar, Cristobal N; Cervantes, Francisco J

    2016-05-01

    Metal-humic acid complexes were synthesized and immobilized by a granulation process in anaerobic sludge for their application as solid-phase redox mediators (RM) in the biotransformation of iopromide. Characterization of Ca- and Fe-humic acid complexes revealed electron accepting capacities of 0.472 and 0.556milli-equivalentsg(-1), respectively. Once immobilized, metal-humic acid complexes significantly increased the biotransformation of iopromide in upflow anaerobic sludge blanket (UASB) reactors. Control UASB reactor (without humic material) achieved 31.6% of iopromide removal, while 80% was removed in UASB reactors supplied with each metal-humic acid complex. Further analyses indicated multiple transformation reactions taking place in iopromide including deiodination, N-dealkylation, decarboxylation and deacetylation. This is the first successful application of immobilized RM, which does not require a supporting material to maintain the solid-phase RM in long term operation of bioreactors. The proposed redox catalyst could be suitable for enhancing the redox conversion of different recalcitrant pollutants present in industrial effluents. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. A comprehensive structural evaluation of humic substances using several fluorescence techniques before and after ozonation. Part II: evaluation of structural changes following ozonation.

    Science.gov (United States)

    Rodríguez, Francisco J; Schlenger, Patrick; García-Valverde, María

    2014-04-01

    The main objective of this work (Part II) is to evaluate the usefulness of fluorescence techniques to monitor structural changes in humic substances produced by the ozonation treatment, using all the current fluorescence techniques: Emission scan fluorescence (ESF), synchronous fluorescence spectroscopy (SFS), total luminescence spectroscopy (TLS or EEM) through the use of both 2-D contour maps and 3-D plots, fluorescence index and the λ0.5 parameter. Four humic substances were studied in this work: three of them were provided by the International Humic Substances Society (Suwannee River Fulvic Acid Standard: SUFA, Suwannee River Humic Acid Standard: SUHA and Nordic Reservoir Fulvic Acid Reference: NOFA) and the other one was a commercial humic acid widely used as a surrogate for aquatic humic substances in various studies (Aldrich Humic Acid: ALHA). The lowest ozone dosage tested (0.25mg O3/mg TOC) caused no appreciable change in the different types of fluorescence spectra under study, therefore the structural change produced in the humic macromolecules may be considered of little significance. Concerning EEM and synchronous spectra, the two natural fulvic acids (SUFA and NOFA) showed a decrease in fluorescence intensity as ozone dosage increased, but the natural humic acid (SUHA) showed a different behaviour: an initial increase in fluorescence intensity at medium ozone dosages (1.5 mg O3/mg TOC) followed by an intensity decrease for the higher ozone dose (7.5 mg O3/mg TOC). Regarding synchronous spectra, the moderate dosage of 1.5 mg O3/mg TOC led to an increase in the fluorescence of the protein-like peak at λsyn=285 nm for the natural humic substances. The results obtained for the fluorescence index and λ0.5 may suggest that the greatest degradation of aromatic structures within the humic macromolecule occurs at high ozone dosages, whereas the predominant effect at moderate dosages would be the break-up of the humic macromolecule into lower molecular weight

  2. Uranium accumulation in Brassica rapa L. and effect of citric acid and humic acids as chelating agents; Acumulacion de uranio en Brassica rapa L. y efecto del acido citrico y acidos humicos como agentes quelantes

    Energy Technology Data Exchange (ETDEWEB)

    Lopez del R, H.; Perez C, G. A.; Davila R, J. I.; Mireles G, F. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98060 Zacatecas, Zac. (Mexico); Rodriguez H, G., E-mail: hlopezdelrio@hotmail.com [Universidad Autonoma de Zacatecas, Unidad Academica de Agronomia, Carretera Zacatecas-Guadalajara Km 15.5, Cieneguillas, Zacatecas (Mexico)

    2016-09-15

    Phyto extraction is a technique that makes use of plants for the remediation of soils contaminated with heavy metals. In this study the uranium incorporation in the Brassica rapa L. species was evaluated, in artificially contaminated inert soils with 40 mg U/kg, and the effect of adding of the natural chelating agents citric acid and humic acids in the accumulation of uranium was analyzed. Soil free of organic matter and biologically inert was obtained by controlled calcination s of natural soil. Cultures in the prepared soil consisted of five growth treatments: 1) cultivation without uranium or additives; 2) cultivation in the uranium presence; 3) cultivation with uranium and citric acid (2 g/kg); 4) cultivation with uranium and humic acids (10 g/kg); 5) uranium cultivation and combination of citric and humic acids at the same concentrations. There was no adverse effect on plant growth with the presence of uranium at the given concentration. Regarding the controls, the total biomass in the presence of uranium was slightly higher, while the addition of humic acids significantly stimulated the production of biomass with respect to the citric acid. The combined action of organic acids produced the highest amount of biomass. The efficiency of phyto extraction followed the order Humic acids (301 μg U/g) > Non-assisted (224 μg U/g) >> Citric acid + Humic acids (68 μg U/g) > Citric acid (59 μg U/g). The values of uranium concentration in the total biomass show that the species Brassica rapa L. has the capacity of phyto extraction of uranium in contaminated soils. The addition of humic acids increases the uranium extraction while the addition of citric acid disadvantages it. (Author)

  3. Heavy metal / polyacid interaction : an electrochemical study of the binding of Cd(II), Pb(II) and Zn(II) to polycarboxylic and humic acids

    NARCIS (Netherlands)

    Cleven, R.F.M.J.

    1984-01-01

    Polyelectrolyte effects in the interaction of heavy metal ions with model polycarboxylic acids have been described, in order to establish the relevance of these effects in the interaction of heavy metal ions with naturally occurring humic and fulvic acids. The model systems consisted of Cd(II),

  4. Effect of humic acids on intestinal viscosity, leaky gut and ammonia excretion in a 24 h feed restriction model to induce intestinal permeability in broiler chickens

    Science.gov (United States)

    Humic acids (HA) are produced by biodegradation of organic matter that involves physical, chemical and microbiological processes, hence, HA are a complex mixture of many different acids containing carboxyl and phenolate groups. The purpose of this study was to evaluate the effect of HA on intestina...

  5. Effect of cysteine and humic acids on bioavailability of Ag from Ag nanoparticles to a freshwater snail

    Science.gov (United States)

    Luoma, Samuel N.; Tasha Stoiber,; Croteau, Marie-Noele; Isabelle Romer,; Ruth Merrifeild,; Lead, Jamie

    2016-01-01

    Metal-based engineered nanoparticles (NPs) will undergo transformations that will affect their bioavailability, toxicity and ecological risk when released to the environment, including interactions with dissolved organic material. The purpose of this paper is to determine how interactions with two different types of organic material affect the bioavailability of silver nanoparticles (AgNPs). Silver uptake rates by the pond snail Lymnaea stagnalis were determined after exposure to 25 nmol l-1 of Ag as PVP AgNPs, PEG AgNPs or AgNO3, in the presence of either Suwannee River humic acid or cysteine, a high-affinity thiol-rich organic ligand. Total uptake rate of Ag from the two NPs was either increased or not strongly affected in the presence of 1 – 10 mg 1-1 humic acid. Humic substances contain relatively few strong ligands for Ag explaining their limited effects on Ag uptake rate. In contrast, Ag uptake rate was substantially reduced by cysteine. Three components of uptake from the AgNPs were quantified in the presence of cysteine using a biodynamic modeling approach: uptake of dissolved Ag released by the AgNPs, uptake of a polymer or large (>3kD) Ag-cysteine complex and uptake of the nanoparticle itself. Addition of 1:1 Ag:cysteine reduced concentrations of dissolved Ag, which contributed to, but did not fully explain the reductions in uptake. A bioavailable Ag-cysteine complex (> 3kD) appeared to be the dominant avenue of uptake from both PVP AgNPs and PEG AgNPs in the presence of cysteine. Quantifying the different avenues of uptake sets the stage for studies to assess toxicity unique to NPs.

  6. Effects of long-term fertilization on soil humic acid composition and structure in Black Soil.

    Science.gov (United States)

    Zhang, Jiuming; Wang, Jingkuan; An, Tingting; Wei, Dan; Chi, Fengqin; Zhou, Baoku

    2017-01-01

    The composition and structure of humic acid (HA) can be affected by fertilization, but the short-term effects are difficult to detect using traditional analysis methods. Using a 35-year long-term experiment in Black Soil, the molecular structure of HA was analyzed with Fourier transform infrared spectroscopy (FTIR), 13C nuclear magnetic resonance spectroscopy (NMR), and fluorescence spectroscopy. Variation in HA was analyzed after long-term fertilization, including fertilization with manure (M), inorganic N, P and K fertilizer (NPK), manure combined with inorganic N, P, and K fertilizer (MNPK), and a no-fertilizer control (CK). The application of each fertilizer treatment increased crop yields compared with the CK treatment, and the MNPK treatment increased crop yield the most. The ratio of main IR absorption peak of HA at 2,920 cm-1 compared with the peak at 2,850 cm-1 (2920/2850) was higher in the NPK and MNPK treatments compared with the CK treatment. The application of manure (MNPK and M treatments) increased the ratio of hydrogen to carbon (H/C) in HA, and raised the ratio of the main IR absorption peak of HA at 2920 cm-1 to that at 1720 cm-1 (2920/1720). Manure treatments also raised the ratio of aliphatic carbon (C) to aromatic C, alkyl C to alkoxy C and hydrophobic C to hydrophilic C and the fluorescence index (f 450/500), but decreased the degree of aromatization of HA, when compared with the CK treatment. The ratio between each type of C in HA was similar among all the fertilizer treatments, but NPK had a lower ratio of H/C and a lower content of aliphatic C compared with the CK treatment. These results indicated that the molecular structure of HA in Black Soil tends to be aliphatic, simpler, and younger after the application of manure. While the application of inorganic fertilizers increased in the degree of condensation of HA and made HA structure complicated. The application of manure alone or combined with inorganic fertilizers may be an effective way

  7. Sorption behaviour of microelements in aqueous solutions in the presence of humic acid

    International Nuclear Information System (INIS)

    Polyakov, E.V.; Surikov, V.T.; Moskova, N.S.; Zhernakova, Z.M.

    2006-01-01

    Migration of stable and radioactive forms of microelements in soil as a result of interaction of atmosphere fallouts with monazite sand is one of the factors of a local radiological situation in Sverdlovsk Region of Urals, Russia. Though no experimental data exist on the physicochemical state in soil of such water soluble products as Th(IV), U(VI), lanthanides (REE), thermodynamic analysis predicts crucial role of humic acids (HA) in the complexation of these elements in natural heterogeneous aqueous media. The object of our research consisted in the experimental evaluation of the impact of Th(IV), U(VI), REE(III) physicochemical state on their partitioning between a cation exchanger (CE) and aqueous solution of HA (800-900 mg HA/L). Determination of equilibrium abundance of the elements in the CE, insoluble fraction of HA and water allowed us to trace both general (ε b ) and partial (ε KY2 , ε HA ) behaviour of more than 20 major and minor elements in the system 'HA-CE-HCl-NaOH-H 2 O' as a function of pH. Sorption system 'CE-HCl-NaOH-H 2 O-microelement' was selected as a reference one with regard to the chemical state of microelements. It was shown that sorption behaviour of Th(IV), U(VI), lanthanides(III) and a number of other microelements toward CE in the reference system is fully determined by the formation of aqua-hydroxo- and mixed hydroxo-carbonate complexes of these elements. For example, in the case of U(VI), the partitioning of positively charged hydroxo complexes leads to cupola-shaped isotherm of sorption due to the formation of non-adsorbable uranium carbonate complexes at pH>6. Presence of HA in sorption system changes substantially the sorption behaviour of microelements due to the formation of strong HA-complexes at pH>4 and insoluble HA solid at pH<4. The peculiarities of sorption behaviour of Th(IV), U(VI) and lanthanides(III) in the investigated systems are discussed in detail. (author)

  8. Speciation of chromium compounds from humic acid-zeolite Y to an ionic liquid during extraction.

    Science.gov (United States)

    Huang, Hsin-Liang; Wei, Yu Jhe

    2018-03-01

    By synchrotron X-ray absorption spectroscopy, chemical structures of hexavalent chromium (Cr(VI))/trivalent chromium (Cr(III)) adsorbed on humic acid (HA)-zeolite Y and extracted in an ionic liquid (1-butyl-3-methylimidazolium tetrafluoroborate ([C 4 mim][BF 4 ])) have been studied. By combining the competitive adsorption results and reduction of Cr(VI)-HA with the carboxyl groups of HA, Cr(III)-HA (58%) was shown to be the major compound in HA-zeolite Y using synchrotron X-ray absorption near-edge structure (XANES) spectroscopy. In an ionic liquid phase, the reduction of Cr(VI)-HA to Cr(III)-HA and the desorption of Cr(III) from HA were caused by [C 4 mim][BF 4 ]. The 9 F nuclear magnetic resonance (NMR) spectra show that the perturbation of the [C 4 mim][BF 4 ] anion was affected by the extractable chromium species. The formation of a Cr(III) ion affected the increase in the bond distance for the 1st shell CrO of the chromium species in [C 4 mim][BF 4 ] using extended X-ray absorption fine structure (EXAFS) spectroscopy. The changes in the non-extractable chromium species remaining in HA-zeolite Y were also caused by [C 4 mim][BF 4 ] during extraction. The desorption of the absorbed Cr(III) on HA and zeolite Y was observed to form Cr(III) ions. As the percentage of Cr(III) ions remaining in HA-zeolite Y increased, a slightly greater bond distance for CrO was found at 2.01 Å. The enhanced reduction of Cr(VI)-HA and desorption of Cr(III) adsorbed on the HA and zeolite Y to form Cr(III) ions were affected by [C 4 mim][BF 4 ]. Increased mobility of Cr(III) in the simulated soil can promote the migration of Cr(III) ions into the H 2 O during soil washing for remediation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Characterization of humic acid reactivity modifications due to adsorption onto α-Al 2O 3

    KAUST Repository

    Janot, Noémie

    2012-03-01

    Adsorption of purified Aldrich humic acid (PAHA) onto α-Al 2O 3 is studied by batch experiments at different pH, ionic strength and coverage ratios R (mg of PAHA by m 2 of mineral surface). After equilibration, samples are centrifuged and the concentration of PAHA in the supernatants is measured. The amount of adsorbed PAHA per m 2 of mineral surface is decreasing with increasing pH. At constant pH value, the amount of adsorbed PAHA increases with initial PAHA concentration until a pH-dependent constant value is reached. UV/Visible specific parameters such as specific absorbance SUVA 254, ratio of absorbance values E 2/E 3 and width of the electron-transfer absorbance band Δ ET are calculated for supernatant PAHA fractions of adsorption experiments at pH 6.8, to have an insight on the evolution of PAHA characteristics with varying coverage ratio. No modification is observed compared to original compound for R≥20mgPAHA/gα-Al2O3. Below this ratio, aromaticity decreases with initial PAHA concentration. Size-exclusion chromatography - organic carbon detection measurements on these supernatants also show a preferential adsorption of more aromatic and higher-sized fractions. Spectrophotometric titrations were done to estimate changes of reactivity of supernatants from adsorption experiments made at pH ≈6.8 and different PAHA concentrations. Evolutions of UV/Visible spectra with varying pH were treated to obtain titration curves that are interpreted within the NICA-Donnan framework. Protonation parameters of non-sorbed PAHA fractions are compared to those obtained for the PAHA before contact with the oxide. The amount of low proton-affinity type of sites and the value of their median affinity constant decrease after adsorption. From PAHA concentration in the supernatant and mass balance calculations, "titration curves" are experimentally proposed for the adsorbed fractions for the first time. These changes in reactivity to our opinion could explain the difficulty

  10. Competitive effects of humic acid and wastewater on adsorption of Methylene Blue dye by activated carbon and non-imprinted polymers.

    Science.gov (United States)

    Murray, Audrey; Örmeci, Banu

    2018-04-01

    Natural organic matter (NOM), present in natural waters and wastewater, decreases adsorption of micropollutants, increasing treatment costs. This research investigated mechanisms of competition for non-imprinted polymers (NIPs) and activated carbon with humic acid and wastewater. Three different types of activated carbons (Norit PAC 200, Darco KB-M, and Darco S-51) were used for comparison with the NIP. The lower surface area and micropore to mesopore ratio of the NIP led to decreased adsorption capacity in comparison to the activated carbons. In addition, experiments were conducted for single-solute adsorption of Methylene Blue (MB) dye, simultaneous adsorption with humic acid and wastewater, and pre-loading with humic acid and wastewater followed by adsorption of MB dye using NIP and Norit PAC 200. Both the NIP and PAC 200 showed significant decreases of 27% for NIP (p=0.087) and 29% for PAC 200 (p=0.096) during simultaneous exposure to humic acid and MB dye. There was no corresponding decrease for NIP or PAC 200 pre-loaded with humic acid and then exposed to MB. In fact, for PAC 200, the adsorption capacity of the activated carbon increased when it was pre-loaded with humic acid by 39% (p=0.0005). For wastewater, the NIP showed no significant increase or decrease in adsorption capacity during either simultaneous exposure or pre-loading. The adsorption capacity of PAC 200 increased by 40% (p=0.001) for simultaneous exposure to wastewater and MB. Pre-loading with wastewater had no effect on MB adsorption by PAC 200. Copyright © 2017. Published by Elsevier B.V.

  11. Kinetics of the oxidative hydroxylation of sodium hypophosphite in the presence of copper (II chloride modified by humic (fulvo- acid

    Directory of Open Access Journals (Sweden)

    Zhaksyntay Kairbekov

    2012-12-01

    Full Text Available It was established that in soft conditions (50-70oC, PO2 = 1 atm sodium hypophosphite effectively is oxidized by oxygen in water solutions of copper(II chloride  to give mainly a phosphorous acid. Humic (fulvo- acid was extracted from brown coal of domestic deposit Kiyakty. For determination of optimum parameters of fulvo-acid extraction the laboratory experiments were carried out using the method of experiment planning. The kinetics, the intermediate and final products, optimal conditions of new catalytic reaction of NaH2PO2 oxidation by oxygen in water solution were defined by kinetics, volumometry, redox-potentiometry and a titration.

  12. Covalent binding of sulfamethazine to natural and synthetic humic acids: assessing laccase catalysis and covalent bond stability.

    Science.gov (United States)

    Gulkowska, Anna; Sander, Michael; Hollender, Juliane; Krauss, Martin

    2013-07-02

    Sulfonamide antibiotics form stable covalent bonds with quinone moieties in organic matter via nucleophilic addition reactions. In this work, we combined analytical electrochemistry with trace analytics to assess the catalytic role of the oxidoreductase laccase in the binding of sulfamethazine (SMZ) to Leonardite humic acid (LHA) and to four synthetic humic acids (SHAs) polymerized from low molecular weight precursors and to determine the stability of the formed bonds. In the absence of laccase, a significant portion of the added SMZ formed covalent bonds with LHA, but only a very small fraction (<0.4%) of the total quinone moieties in LHA reacted. Increasing absolute, but decreasing relative concentrations of SMZ-LHA covalent bonds with increasing initial SMZ concentration suggested that the quinone moieties in LHA covered a wide distribution in reactivity for the nucleophilic addition of SMZ. Laccase catalyzed the formation of covalent bonds by oxidizing unreactive hydroquinone moieties in LHA to reactive, electrophilic quinone moieties, of which a large fraction (5%) reacted with SMZ. Compared to LHA, the SHA showed enhanced covalent bond formation in the absence of laccase, suggesting a higher reactivity of their quinone moieties toward nucleophilic addition. This work supports that binding to soil organic matter (SOM) is an important process governing the fate, bioactivity, and extractability of sulfonamides in soils.

  13. Application of a set of complementary techniques to understand how varying the proportion of two wastes affects humic acids produced by vermicomposting

    Energy Technology Data Exchange (ETDEWEB)

    Fernández-Gómez, Manuel J., E-mail: manuelj.fernandez@eez.csic.es [Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Profesor Albareda 1, 18008 Granada (Spain); Nogales, Rogelio [Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Profesor Albareda 1, 18008 Granada (Spain); Plante, Alain [Department of Earth and Environmental Science, University of Pennsylvania, Hayden Hall, 240 S. 33rd Street, Philadelphia, PA 19104 (United States); Plaza, César [Instituto de Ciencias Agrarias, Consejo Superior de Investigaciones Científicas, Serrano 115, 28006 Madrid (Spain); Fernández, José M. [Department of Earth and Environmental Science, University of Pennsylvania, Hayden Hall, 240 S. 33rd Street, Philadelphia, PA 19104 (United States); Instituto de Ciencias Agrarias, Consejo Superior de Investigaciones Científicas, Serrano 115, 28006 Madrid (Spain)

    2015-01-15

    Highlights: • A set of techniques was used to characterize humic acids content of vermicomposts. • The properties of the humic acids produced from different waste mixtures were similar. • This set of techniques allowed distinguishing the humic acids of each vermicomposts. • Increasing humic acid contents in initial mixtures would produce richer vermicomposts. - Abstract: A better understanding of how varying the proportion of different organic wastes affects humic acid (HA) formation during vermicomposting would be useful in producing vermicomposts enriched in HAs. With the aim of improving the knowledge about this issue, a variety of analytical techniques [UV–visible spectroscopic, Fourier transform infrared, fluorescence spectra, solid-state cross-polarization magic-angle spinning (CPMAS) {sup 13}C nuclear magnetic resonance (NMR) spectra, and thermal analysis] was used in the present study to characterize HAs isolated from two mixtures at two different ratios (2:1 and 1:1) of tomato-plant debris (TD) and paper-mill sludge (PS) before and after vermicomposting. The results suggest that vermicomposting increased the HA content in the TD/PS 2:1 and 1:1 mixtures (15.9% and 16.2%, respectively), but the vermicompost produced from the mixture with a higher amount of TD had a greater proportion (24%) of HAs. Both vermicomposting processes caused equal modifications in the humic precursors contained in the different mixtures of TD and PS, and consequently, the HAs in the vermicomposts produced from different waste mixtures exhibited analogous characteristics. Only the set of analytical techniques used in this research was able to detect differences between the HAs isolated from each type of vermicompost. In conclusion, varying the proportion of different wastes may have a stronger influence on the amount of HAs in vermicomposts than on the properties of HAs.

  14. An investigation of the characteristics of humic acid and of its effects on the chemistry of the near field of a radioactive waste repository

    International Nuclear Information System (INIS)

    Bates, C.I.; Bayliss, S.; Gardiner, M.P.; Hobley, J.; Smith, A.J.; Williams, S.J.

    1993-01-01

    The work described in this report attempts to assess the possible effects of humic substances in the near field of a radioactive waste repository. Two samples of humic acid were studied by analytical ultracentrifugation. It was found to be an advantage to reduce sample polydispersity before carrying out molecular weight determinations. Ultrafiltration experiments showed that calcium concentrations of greater than 10 -3 M were sufficient to cause precipitation of humic acid. Boom clay extracts in sodium hydroxide solution were able to maintain high concentrations of americium in the aqueous phase. Extracts of Boom clay in cement-equilibrated water showed less ability to increase americium concentrations. The sorption of americium on BFS/OPC was studied. Distribution ratios of 600 ml g -1 in the absence of humic acid and 500 ml g -1 in its presence were obtained. Size distribution studies on americium showed that humic acid had little effect on the concentration of the radioelement in solutions passed through filters with up to 2 μm pore size. However, size distribution studies on plutonium revealed that more plutonium was associated with each filtered fraction in the experiments which contained Boom clay extract than in those which used cement-equilibrated water. Measurements of the sorption of neptunium on cements showed that this radioelement was strongly sorbed onto both 9:1 BFS/OPC and the Nirex reference backfill. The presence of humic acid extracted from Boom clay did not cause any discernible decrease in the sorption of this radioelement on cement. Thermodynamic calculations, using a simple model, illustrate the important role which calcium could play in controlling the concentrations of actinide humates in the near-field porewater. 31 refs., 19 figs., 12 tabs

  15. An investigation of the characteristics of humic acid and of its effects on the chemistry of the near field of a radioactive waste repository

    International Nuclear Information System (INIS)

    Bates, C.I.; Bayliss, S.; Gardiner, M.P.; Hobley, J.; Smith, A.J.; Williams, S.J.

    1992-07-01

    The work described in this report attempts to assess the possible effects of humic substances in the near field of a radioactive waste repository. Two samples of humic acid were studied by analytical ultracentrifugation. It was found to be an advantage to reduce sample polydispersity before carrying out molecular weight determinations. Ultrafiltration experiments showed that calcium concentrations of greater than 10 -3 M were sufficient to cause precipitation of humic acid. Boom clay extracts in sodium hydroxide solution were able to maintain high concentrations of americium in the aqueous phase. Extracts of Boom clay in cement-equilibrated water showed less ability to increase americium concentrations. The sorption of americium on BFS/OPC was studied. Distribution ratios of 600 ml g -1 in the absence of humic acid and 500 ml g -1 in its presence were obtained. Size distribution studies on americium showed that humic acid had little effect on the concentration of the radioelement in solutions passed through filters with up to 2 μm pore size. However, size distribution studies on plutonium revealed that more plutonium was associated with each filtered fraction in the experiments which contained Boom clay extract than in those which used cement-equilibrated water. Measurements of the sorption of neptunium on cements showed that this radioelement was strongly sorbed onto both 9:1 BFS/OPC and the Nirex reference backfill. The presence of humic acid extracted from Boom clay did not cause any discernible decrease in the sorption of this radioelement on cement. Thermodynamic calculations, using a simple model, illustrate the important role which calcium could play in controlling the concentrations of actinide humates in the near-field porewater. (author)

  16. Radiotracer study of europium interaction with humic acid using electrophoresis, ultrafiltration, and dialysis

    Czech Academy of Sciences Publication Activity Database

    Mizera, Jiří; Mizerová, Gabriela; Beneš, P.

    2005-01-01

    Roč. 263, č. 1 (2005), s. 75-80 ISSN 0236-5731. [International Conference on Methods and Applications of Radioanalytical Chemistry, MARC VI. Kailua-Kona, Hawaii, 07.04.2003-11.04.02003] Institutional research plan: CEZ:AV0Z10480505 Keywords : humic substances * europium * radiotracer technique Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 0.460, year: 2005

  17. H-binding of size- and polarity-fractionated soil and lignite humic acids after removal of metal and ash components

    Science.gov (United States)

    Drosos, Marios; Leenheer, Jerry A.; Avgeropoulos, Apostolos; Deligiannakis, Yiannis

    2014-01-01

    A fractionation technique, combining dialysis removal of metal and ash components with hydrofluoric acid and pH 10 citrate buffer followed by chromatography of dialysis permeate on XAD-8 resin at decreasing pH values, has been applied to lignite humic acid (lignite-HA) and soil humic acid (soil-HA). H-binding data and non ideal competitive adsorption-Donnan model parameters were obtained for the HA fractions by theoretical analysis of H-binding data which reveal a significant increase of the carboxyl and the phenolic charge for the lignite-HA fractions vs. the parental lignite humic acid (LParentalHA). The fractionated lignite-HA material consisted mainly of permeate fractions, some of which were fulvic acid-like. The fractionated soil-HA material consisted mainly of large macromolecular structures that did not permeate the dialysis membrane during deashing. Chargeable groups had comparable concentrations in soil-HA fractions and parental soil humic acid (SParentalHA), indicating minimal interference of ash components with carboxyl and phenolic (and/or enolic) groups. Fractionation of HA, combined with theoretical analysis of H-binding, can distinguish the supramolecular vs. macromolecular nature of fractions within the same parental HA.

  18. Unrefined humic substances as a potential low-cost amendment for the management of acidic groundwater contamination.

    Science.gov (United States)

    Gonzalez-Raymat, Hansell; Anagnostopoulos, Vasileios; Denham, Miles; Cai, Yong; Katsenovich, Yelena P

    2018-02-09

    The present study explores a novel application of Huma-K, a commercially available, unrefined humic substance, as a promising low-cost source of organic matter for in situ remediation of contaminated acidic groundwater plumes. This can be achieved by creating a humic-rich coating on the surface of minerals which can enhance the sorption of contaminants from groundwater. Huma-K was characterized by means of scanning electron microscopy equipped with energy dispersive spectroscopy, Fourier-transform infrared analysis, and potentiometric titrations. Batch experiments were performed to investigate the sorption-desorption behavior of Huma-K and to evaluate what conditions (pH, contact time, and initial Huma-K concentration) affect these processes upon injection into aquifer sediments. As evidenced by potentiometric titrations, Huma-K possesses functional groups that have an acidic nature, with pK values in the range of 4-6 (carboxylic) and 9-10 (phenolic). Sorption, homogeneous precipitation, and surface-induced precipitation seem to be favored in the presence of sediment at pH 4, where there is less deprotonation of acidic functional groups. As the pH is increased, functional groups become negatively charged, leading to electrostatic repulsion and dissolution of Huma-K from sediment. Kinetic experiments indicate that Huma-K sorption is a slow-rate process, most likely governed by film diffusion. The enhanced sorption of Huma-K in acidic conditions suggests that it may be used to create a subsurface treatment zone in acidic aquifers for the sequestration of contaminants such as uranium. The treatment zone will persist as long as the pH does not increase sufficiently to cause soil-bound Huma-K to be released, remobilizing aqueous contaminants. Copyright © 2018 Elsevier Ltd. All rights reserved.

  19. Low molecular weight components in an aquatic humic substance as characterized by membrane dialysis and orbitrap mass spectrometry.

    Science.gov (United States)

    Remucal, Christina K; Cory, Rose M; Sander, Michael; McNeill, Kristopher

    2012-09-04

    Suwannee River fulvic acid (SRFA) was dialyzed through a 100-500 molecular weight cutoff dialysis membrane, and the dialysate and retentate were analyzed by UV-visible absorption and high-resolution Orbitrap mass spectrometry (MS). A significant fraction (36% based on dissolved organic carbon) of SRFA passed through the dialysis membrane. The fraction of SRFA in the dialysate had a different UV-visible absorption spectrum and was enriched in low molecular weight molecules with a more aliphatic composition relative to the initial SRFA solution. Comparison of the SRFA spectra collected by Orbitrap MS and Fourier transform ion cyclotron resonance MS (FT-ICR MS) demonstrated that the mass accuracy of the Orbitrap MS is sufficient for determination of unique molecular formulas of compounds with masses masses detected by Orbitrap MS were found in the 100-200 Da mass range. Many of these low molecular masses corresponded to molecular formulas of previously identified compounds in organic matter, lignin, and plants, and the use of the standard addition method provided an upper concentration estimate of selected target compounds in SRFA. Collectively, these results provide evidence that SRFA contains low molecular weight components that are present individually or in loosely bound assemblies.

  20. Acid deposition in aquatic ecosystems: Setting limits empirically

    Science.gov (United States)

    Newcombe, Charles P.

    1985-07-01

    The problem of acid deposition and its harmful effects on aquatic ecosystems has created a new branch of science that is called upon to provide the knowledge on which legislative controls can be based. However, because of the nature of existing legislation, which requires evidence of cause and effect between industrial emissions and pollution, and because of science's inability to provide this information over the short term, considerable controversy has arisen about whether sufficient information exists to warrant control measures at this time. Among those who advocate controls, there is genuine divergence of opinion about how stringent the controls must be to achieve any desired level of protection. The controversy has led to an impasse between the scientific and political participants, which is reflected in the slow pace of progress toward an effective management strategy. Resolution of the impasse, at least in the short term, may demand that science and politics rely on empirical models rather than explanatory ones. The empirical model, which is the major proposal in this article, integrates all of the major variables and many of the minor ones, and constructs a three-dimensionally curved surface capable of representing the status of any waterbody subjected to the effects of acid deposition. When suitably calibrated—a process involving the integration of knowledge and data from aquatic biology, geochemistry, meteorology, and limnology—it can be used to depict limits to the rate of acid deposition required for any level of environmental protection. Because it can generate a pictorial display of the effects of management decisions and legislative controls, the model might serve as a basis for enhancing the quality of communication among all the scientific and political participants and help to resolve many of their controversies.

  1. Application of microwave energy to speed up the alkaline extraction of humic and fulvic acids from marine sediments

    Energy Technology Data Exchange (ETDEWEB)

    Romaris-Hortas, Vanessa; Moreda-Pineiro, Antonio [Department of Analytical Chemistry, Nutrition and Bromatology, Faculty of Chemistry, University of Santiago de Compostela, Avenida das Ciencias s/n, 15782 Santiago de Compostela (Spain); Bermejo-Barrera, Pilar [Department of Analytical Chemistry, Nutrition and Bromatology, Faculty of Chemistry, University of Santiago de Compostela, Avenida das Ciencias s/n, 15782 Santiago de Compostela (Spain)], E-mail: pbermejo@usc.es

    2007-10-29

    The feasibility of microwave energy to speed up the alkaline extraction of humic substances (humic acid, HA, and fulvic acid, FA) from marine sediments has been checked. Extractions were performed by using 20 mL of sodium hydroxide at 0.1 M (two repeated extractions) after an ultrasound-assisted acid pre-treatment of samples to remove the carbonate fraction (ultrasound power at 17 kHz, 10 mL of 6.0 M hydrochloric acid for 15 min). After separation of HA and FA fractions by acidifying with 6 M HCl, the FA fraction (supernatant) was purified by passing the solution through a column of Amberlite XAD-8. Both HA and FA extracts were measured by UV-visible spectrophotometry. All variables affecting the extraction process (sodium hydroxide concentration and volume, ramp and hold times, temperature and number of repeated extractions) have been screened by using a Plackett-Burman design (PBD) as multivariate approach. The variables temperature and number of repeated extractions were the most significant factors (P = 95%) affecting the extraction of both FA and HA from marine sediments. These two variables have led optimum values of 150 deg. C and two repeated extractions. The developed method has been found precise (R.S.D.s of 9% for HA and 12% for FA, for 11 determinations) and its results were comparable in terms of elemental (C, H and N) composition to those obtained after applying methods based on mechanical stirring and ultrasounds assisting. However, higher HA and FA concentrations than those obtained after conventional stirring and ultrasound irradiation were obtained when applying microwave energy. This means a higher efficiency of microwave energy than ultrasounds or mechanical stirring to extract HA and FA fractions from marine sediments. The method was finally applied to different surface marine sediments from the Ria de Arousa estuary.

  2. Introducing Environmental and Sustainable Chemistry Topics Using a Nanotechnology Approach: Removing Hazardous Metal Ions by Means of Humic-Acid-Modified Superparamagnetic Nanoparticles

    Science.gov (United States)

    Gomes da Silva, Delmarcio; Menegatti de Melo, Fernando; Silveira, Alceu Totti, Jr.; Constancio da Cruz, Bruno; Prado, Caio Cesar Pestana; Pereira de Vasconcelos, Luana Cristina; Lucas, Vitor Amaral Sanches; Toma, Henrique Eisi

    2016-01-01

    A laboratory experiment has been developed to illustrate environmental and sustainability aspects, focusing on the wastewater treatment by means of superparamagnetic nanoparticles functionalized with humic acid. The experiment, conducted by a group of high school students, involves nanoparticle synthesis and minor characterization, followed by…

  3. THE INFLUENCE OF pH TOWARDS MULTIPLE METAL ION ADSORPTION OF Cu(II, Zn(II, Mn(II, AND Fe(II ON HUMIC ACID

    Directory of Open Access Journals (Sweden)

    Buhani Buhani

    2010-06-01

    Full Text Available Multiple metal ions adsorption of Cu(II, Zn(II, Mn(II and Fe(II on humic acid with a batch method has been carried out at pH interaction of 3, 5, and 6. Concentration of metal ions in solution before and after interaction was analyzed with Atomic Absorption Spectrophotometer (AAS. Result showed that adsorption multiple metal ions of Cu(II, Zn(II, Mn(II, and Fe(II on humic acid is optimum at pH 5. Adsorption energies of the multiple metal ions Cu(II, Zn(II, Mn(II, and Fe(II on humic acid at pH 3, 5, and 6 are around 35.0 - 37.6 kJ/mole. In general, capacity of competition adsorption of the multiple metal ions has an order as follows; Cu(II < Fe(II < Zn(II < Mn(II.   Keywords: Humic acid, adsorption, multiple metal

  4. Batch experiments for assessing the sorption/desorption characteristics of 152Eu in systems of loose sediments and water containing humic acids

    International Nuclear Information System (INIS)

    Klotz, D.

    2001-01-01

    The 152 Eu distribution coefficients of the sorption and desorption of non-binding loose sediments of different grain sizes are investigated using a groundwater of tertiary lignite from Northern Germany which contains high concentrations of humic acids. The batch experiments were carried out with a ratio of 2.5cm 3 /g of solution volume to sediment mass, without mixing [de

  5. Synergistic removal of Pb(II, Cd(II and humic acid by Fe3O4@mesoporous silica-graphene oxide composites.

    Directory of Open Access Journals (Sweden)

    Yilong Wang

    Full Text Available The synergistic adsorption of heavy metal ions and humic acid can be very challenging. This is largely because of their competitive adsorption onto most adsorbent materials. Hierarchically structured composites containing polyethylenimine-modified magnetic mesoporous silica and graphene oxide (MMSP-GO were here prepared to address this. Magnetic mesoporous silica microspheres were synthesized and functionalized with PEI molecules, providing many amine groups for chemical conjugation with the carboxyl groups on GO sheets and enhanced the affinity between the pollutants and the mesoporous silica. The features of the composites were characterized using TEM, SEM, TGA, DLS, and VSM measurements. Series adsorption results proved that this system was suitable for simultaneous and efficient removal of heavy metal ions and humic acid using MMSP-GO composites as adsorbents. The maximum adsorption capacities of MMSP-GO for Pb(II and Cd (II were 333 and 167 mg g(-1 caculated by Langmuir model, respectively. HA enhances adsorption of heavy metals by MMSP-GO composites due to their interactions in aqueous solutions. The underlying mechanism of synergistic adsorption of heavy metal ions and humic acid were discussed. MMSP-GO composites have shown promise for use as adsorbents in the simultaneous removal of heavy metals and humic acid in wastewater treatment processes.

  6. Dimensão fractal de ácidos húmicos em diferentes condições experimentais Fractal dimension of humic acids in differents experimental condition

    Directory of Open Access Journals (Sweden)

    Alessandro Costa da Silva

    2003-05-01

    Full Text Available The determination of fractal dimension (D of humic particles was achieved by the turbidimetric technique where diluted suspensions of humic acids, in different experimental conditions, were analyzed by spectrophotometry UV-Vis. The slope of the lines (beta was taken from the graphics (logtauvs loglambda to obtain D. The results show that the values of D changed according to pH (3.0, 5.0 and 7.0, temperature (25 and 5 ºC and shaking (magnetic and horizontal. In general, the value of D decreased with the increment of pH, increase of shaking and decrease of temperature.

  7. Physico-chemical analysis of tannery solid waste and structural characterization of its isolated humic acids after composting.

    Science.gov (United States)

    Amir, Soumia; Benlboukht, Fatima; Cancian, Nadia; Winterton, Peter; Hafidi, Mohamed

    2008-12-30

    In Marrakech, solid by-products from tanneries are highly polluting, generating large amounts of nitrogenous and organic matter. In the present study composting is tested as a cost-effective method for waste management to overcome many of the environmental hazards and produce a stable, rich material for soil fertilization. Two composting trials were conducted after neutralization by ammonia or lime. The aim of the neutralization was to avoid the antimicrobial effects of the acidity in the tannery waste, thus ensuring correct composting. Different techniques such as elemental analysis and 13C NMR spectroscopy were applied to analyse humic acids isolated from raw and composted materials, and to monitor the process of tannery waste composting, and the stability and maturity of the final product according to the means of neutralization. Comparison of data showed similar behaviour in both trials, but the composting process appeared to be more complete following neutralization with lime. The C, H and N content decreased, while the O increased. The FTIR and 13C NMR spectra show the decrease of aliphatic compounds demonstrated by the reduction of absorbance around 2922cm(-1) and of the resonance in the C-alkyl area around 0-55ppm. The humic acids newly formed during composting were richer in the O-N alkyl and oxidized aromatic structures that increased almost twofold on composting after neutralization with lime. The first principal component axis PC1 (54%) separated C-aliphatic, C-carboxylic and other less stable and less polycondensed compounds such as polyphenols from the more polycondensed O-N alkyl and oxidized C-aromatic compounds.

  8. Sorption of chlorophenols on microporous minerals: mechanism and influence of metal cations, solution pH, and humic acid.

    Science.gov (United States)

    Yang, Hui; Hu, Yuanan; Cheng, Hefa

    2016-10-01

    Sorption of 2-chlorophenol (2-CP), 2,4-dichlorophenol (2,4-DCP), and 2,4,6-trichlorophenol (2,4,6-TCP) on a range of dealuminated zeolites were investigated to understand the mechanism of their sorption on microporous minerals, while the influence of common metal cations, solution pH, and humic acid was also studied. Sorption of chlorophenols was found to increase with the hydrophobicity of the sorbates and that of the microporous minerals, indicating the important role of hydrophobic interactions, while sorption was also stronger in the micropores of narrower sizes because of greater enhancement of the dispersion interactions. The presence of metal cations could enhance chlorophenol sorption due to the additional electrostatic attraction between metal cations exchanged into the mineral micropores and the chlorophenolates, and this effect was apparent on the mineral sorbent with a high density of surface cations (2.62 sites/nm(2)) in its micropores. Under circum-neutral or acidic conditions, neutral chlorophenol molecules adsorbed into the hydrophobic micropores through displacing the "loosely bound" water molecules, while their sorption was negligible under moderately alkaline conditions due to electrostatic repulsion between the negatively charged zeolite framework and anionic chlorophenolates. The influence of humic acid on sorption of chlorophenols on dealuminated Y zeolites suggests that its molecules did not block the micropores but created a secondary sorption sites by forming a "coating layer" on the external surface of the zeolites. These mechanistic insights could help better understand the interactions of ionizable chlorophenols and metal cations in mineral micropores and guide the selection and design of reusable microporous mineral sorbents for sorptive removal of chlorophenols from aqueous stream.

  9. Surface-enhanced Raman spectroscopy of chernozem humic acid and their fractions obtained by coupled size exclusion chromatography-polyacrylamide gel electrophoresis (SEC-PAGE).

    Science.gov (United States)

    Sanchez-Cortes, S; Corrado, G; Trubetskaya, O E; Trubetskoj, O A; Hermosin, B; Saiz-Jimenez, C

    2006-01-01

    A humic acid extracted from a chernozem soil was fractionated combining size exclusion chromatography and polyacrylamide electrophoresis (SEC-PAGE). Three fractions named A, B, and C+D, with different electrophoretic mobilities and molecular sizes (MS), were obtained and subsequently characterized by thermochemolysis and surface-enhanced Raman spectroscopy (SERS). The data confirmed that fraction A, with the higher MS, was more aliphatic than fractions B and C+D and, in turn, fractions with lower MS (B and C+D) denoted an enrichment in lignin residues. These structural features explain conformational changes when varying the pH in the humic fraction A and indicated that combination of the two techniques is a good approach for characterizing humic substances.

  10. Humic Acids Isolated from Earthworm Compost Enhance Root Elongation, Lateral Root Emergence, and Plasma Membrane H+-ATPase Activity in Maize Roots1

    Science.gov (United States)

    Canellas, Luciano Pasqualoto; Olivares, Fabio Lopes; Okorokova-Façanha, Anna L.; Façanha, Arnoldo Rocha

    2002-01-01

    Earthworms (Eisenia foetida) produce humic substances that can influence plant growth by mechanisms that are not yet clear. In this work, we investigated the effects of humic acids (HAs) isolated from cattle manure earthworm compost on the earliest stages of lateral root development and on the plasma membrane H+-ATPase activity. These HAs enhance the root growth of maize (Zea mays) seedlings in conjunction with a marked proliferation of sites of lateral root emergence. They also stimulate the plasma membrane H+-ATPase activity, apparently associated with an ability to promote expression of this enzyme. In addition, structural analysis reveals the presence of exchangeable auxin groups in the macrostructure of the earthworm compost HA. These results may shed light on the hormonal activity that has been postulated for these humic substances. PMID:12481077

  11. Use of the ion exchange method for the determination of stability constants of trivalent metal complexes with humic and fulvic acids--part I: Eu3+ and Am3+ complexes in weakly acidic conditions.

    Science.gov (United States)

    Wenming, Dong; Hongxia, Zhang; Meide, Huang; Zuyi, Tao

    2002-06-01

    The conditional stability constants for tracer concentrations of Eu(III) and Am(III) with a red earth humic acid (REHA), a red earth fulvic acid (REFA) and a fulvic acid from weathered coal (WFA) were determined at pH 5.2-6.4 (such values are similar to those in non-calcareous soils) in the presence of HAc/NaAc or NaNO3 by using the cation exchange method. It was found that 1:1 complexes were predominately formed in weakly acidic conditions. The total exchangeable proton capacities and the degrees of dissociation of these humic substances were determined by using a potentiometric titration method. The key parameters necessary for the experimental determination of the conditional stability constants of metal ions with humic substances in weakly acidic conditions by using the cation exchange method were discussed. The conditional stability constants of 1:1 complexes obtained in this paper were compared with the literature data of Am(III) determined by using the ion exchange method and the solvent extraction method and with the stability constants of 1:1 complexes of UO2(2+) and Th4+ with the same soil humic substances. These results indicate the great stability of bivalent UO2(2+), trivalent Eu3+, Am3+ and tetravalent Th4+ complexes with humic and fulvic acids in weakly acidic conditions.

  12. Use of the ion exchange method for the determination of stability constants of trivalent metal complexes with humic and fulvic acids--Part I: Eu{sup 3+} and Am{sup 3+} complexes in weakly acidic conditions

    Energy Technology Data Exchange (ETDEWEB)

    Dong Wenming E-mail: dongwm@lzu.edu.cn; Zhang Hongxia; Huang Meide; Tao Zuyi

    2002-06-01

    The conditional stability constants for tracer concentrations of Eu(III) and Am(III) with a red earth humic acid (REHA), a red earth fulvic acid (REFA) and a fulvic acid from weathered coal (WFA) were determined at pH 5.2-6.4 (such values are similar to those in non-calcareous soils) in the presence of HAc/NaAc or NaNO{sub 3} by using the cation exchange method. It was found that 1 : 1 complexes were predominately formed in weakly acidic conditions. The total exchangeable proton capacities and the degrees of dissociation of these humic substances were determined by using a potentiometric titration method. The key parameters necessary for the experimental determination of the conditional stability constants of metal ions with humic substances in weakly acidic conditions by using the cation exchange method were discussed. The conditional stability constants of 1 : 1 complexes obtained in this paper were compared with the literature data of Am(III) determined by using the ion exchange method and the solvent extraction method and with the stability constants of 1 : 1 complexes of UO{sub 2}{sup 2+} and Th{sup 4+} with the same soil humic substances. These results indicate the great stability of bivalent UO{sub 2}{sup 2+}, trivalent Eu{sup 3+}, Am{sup 3+} and tetravalent Th{sup 4+} complexes with humic and fulvic acids in weakly acidic conditions.

  13. Impact of Humic Acid on Yield and Quality of Sugar Beet (Beta vulgaris L. Grown on Calcareous Soil

    Directory of Open Access Journals (Sweden)

    Ghorbanali RASSAM

    2015-09-01

    Full Text Available A field experiment was performed to determine the effects of using humic acid with irrigation on quantitative and qualitative yield traits of sugar beet grown on calcareous soils in Esfaraen, located in the North-East of Iran. Treatments consisted of three levels of humic acid concentration (zero or control, 2.5 and 5 L ha-1 and the number of applications (once 45 days after planting; twice, 45 and 75 days after planting; three times, respectively 45, 75 and 105 days after planting. The effect of the two experimental factors on sugar beet yield traits such as the content of sucrose, refined sugar, molasses forming substances, root yield and refined sugar yield were evaluated. The results proved the existence of a significant interaction between humic acid concentration and the number of applications on all parameters under study. The application of humic acid caused a significant increase of sucrose, refined sugar, root yield and refined sugar yield and a reduction in molasses forming substances content, compared to the control. The increased amount of sucrose and refined sugar content in all applications in concentration of 2.5 L ha-1 humic acid was more than with 5 L ha-1. Similarly, the content of molasses forming substances showed more reduction in 2.5 L ha-1 than in 5 L ha-1 treatment. However, the results revealed that the highest root yield and refined sugar yield, as the main qualitative and quantitative parameters of sugar beet yield, were achieved by three times application of 5 L ha-1 that had 24 and 37% increase compared to control.

  14. Radiotracer study of the kinetics of complexation and decomplexation of Eu(III) with humic acid using ion exchange

    International Nuclear Information System (INIS)

    Stamberg, K.; Benes, P.; Mizera, J.; Vopalka, D.; Prochazkova, S.

    2003-01-01

    The kinetics of complexation (C) and decomplexation (D) reactions between Eu(III) and Aldrich humic acid (HA) was investigated as a function of pH (pH 4, 5, 6, 7 and 8) in the system Eu(III) - HA - Amberlite IR-120(Na) (I 0.1). The derivation of the kinetic differential equations was based on the reactions of Eu 3+ with, so called, strong (HAS) and weak (HAW) carboxylic groups of HA formulated in accordance with the new complexation model. The differential equations determining d[Eu a HAS]/dt and d[Eu b HAW]/dt have the classical form applicable for reversible reactions where the forward reaction is the C-reaction and the reverse one is the D-reaction. Kinetic model used for the evaluation of experimental data includes these differential equations and the film diffusion model of sorption of Eu 3+ on Amberlite IR-120(Na). (author)

  15. Direct and indirect photodegradation of estriol in the presence of humic acid, nitrate and iron complexes in water solutions

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yong [Department of Chemistry and Biochemistry, University of Massachusetts Dartmouth, North Dartmouth, MA 02747 (United States); School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); Zhang, Kai [Department of Chemistry and Biochemistry, University of Massachusetts Dartmouth, North Dartmouth, MA 02747 (United States); Zuo, Yuegang, E-mail: yzuo@umassd.edu [Department of Chemistry and Biochemistry, University of Massachusetts Dartmouth, North Dartmouth, MA 02747 (United States)

    2013-10-01

    The photochemical behavior of a natural estrogen estriol (E3) was investigated in the presence of the natural photoreactive constituents including nitrate, iron(III), and humic acid (HA). The direct photodegradation of E3 increased with increasing incident light intensity, decreasing initial concentration of E3 and increasing pH in the range of 6.0 to 10.0. The direct photodegradation of the deprotonated speciation of E3 was much faster than that of its protonated form. The presence of NO{sub 3}{sup −} and iron(III) promoted the photochemical loss of E3 in the aqueous solutions. The quenching experiments verified that hydroxyl radicals were predominantly responsible for the indirect photodegradation of E3. HA could act as photosensitizer, light screening agent and free radical quencher. For the first time, the enhancement or inhibition effect of HA on photodegradation was found to depend on the irradiation light intensity. HA enhanced the photodegradation of E3 under sunlight or weak irradiation of simulated sunlight. In contrast, under high irradiation light intensity, HA inhibited the photodegradation. The hydroxylation photoproducts were identified using GC-MS and the photodegradation pathway of E3 was proposed. - Highlights: • Direct and indirect photodegradation of estriol (E3) were first investigated. • The direct photodegradation of E3 increased with increasing pH of the solutions. • The light intensity affected the photosensitization effect of humic acid. • Nitrate and iron(III) promoted the photodecomposition of estriol in water. • The ·OH oxidation products of E3 was first determined.

  16. Influences of humic acid on the bioavailability of phenanthrene and alkyl phenanthrenes to early life stages of marine medaka (Oryzias melastigma).

    Science.gov (United States)

    Liu, Yangzhi; Yang, Chenghu; Cheng, Pakkin; He, Xiaojing; Zhu, Yaxian; Zhang, Yong

    2016-03-01

    The influences of humic acid (HA) on the environmental behavior and bioavailability of parent polycyclic aromatic hydrocarbons (PAHs) and alkyl PAHs were investigated and compared using the early life stages of marine medaka (Oryzias melastigma, O. melastigma). It was demonstrated that the binding affinity of parent phenanthrene (PHE) with HA was smaller than that of 3-methyl phenanthrene (3-MP) and 9-ethyl phenanthrene (9-EP). Furthermore, the bioaccumulation of the three PAHs and the levels of lipid peroxidation (LPO) were calculated to study the changes in bioavailability of PAHs in presence of HA. The results indicated that the addition of HA significantly decreased the bioaccumulation and toxicity of PAHs by decreasing free PAHs concentrations. The bioavailable fractions of HA-bound PAHs in bioaccumulation (α) and toxicity (β) were evaluated, indicating that the HA-bound 3-MP and 9-EP show higher bioavailability in bioaccumulation and lower bioavailability in toxicity relative to those of PHE. The β/α values were less than 1 for all PAH treatment groups containing HA, suggesting that the fraction of HA-bound PAHs contributing to bioaccumulation was higher than that of HA-bound PAHs inducing toxic effect. In addition, we proposed that the free PAHs generated by desorption from HA in the cell were toxic by showing that the β/α ratio values are correlated with the log KOW values (p = 0.007 and R(2) = 0.8355). Thus, oil spill risk assessments should consider both alkyl PAHs and the factors that influence the bioavailability and toxicity of PAHs in the natural aquatic environments. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Sorption of small molecules to natural organic matter from humic acid to black carbon: a perspective on the nature of pores

    Science.gov (United States)

    Pignatello, J. J.

    2003-04-01

    In recent years our concept of how organic compounds sorb to natural organic matter (NOM) components has undergone re-examination, some would say revision. In this paper I will share results by our group and the results of data pooled from several groups in the U.S. on sorption of PAHs and other apolar chemicals in soils and soil components. These results indicate that most forms of solid NOM contain internal micropores that act to make sorption more or less nonlinear and competitive. Moreover, they show that the pores are irreversibly deformed by the incoming solute. Pore deformation contributes to "irreversible" sorption manifested by hysteresis in the isotherm, and may play a role in slow desorption. The results can be summarized as follows. 1) Sorption to reconstituted humic acid particles (from a variety of sources) is generally nonlinear, although, predictably, usually less nonlinear than sorption to whole soils, humin, ancient forms of organic matter and chars. 2) Sorption to humic acid particles is competitive. 3) Cross-linking humic acid with aluminum ions to increase its glassy character results in enhanced nonlinearity and competition. 4) Sorption to lignin, a random network biopolymer and the main precursor of terrestrial humic substances, is nonlinear. 5) The micropores in macromolecular forms of organic matter, including humic acids, are deformable; this is demonstrated by the "conditioning effect" in which uptake is enhanced after pretreatment of the solid with the same or a different solute. 6) Micropores in a wood charcoal are deformable, as confirm by swelling experiments with benzene. Pore deformation is suggested as the cause of pronounced hysteresis in the benzene isotherm.

  18. Multiple dynamic Al-based floc layers on ultrafiltration membrane surfaces for humic acid and reservoir water fouling reduction.

    Science.gov (United States)

    Ma, Baiwen; Li, Wenjiang; Liu, Ruiping; Liu, Gang; Sun, Jingqiu; Liu, Huijuan; Qu, Jiuhui; van der Meer, Walter

    2018-04-05

    The integration of adsorbents with ultrafiltration (UF) membranes is a promising method for alleviating membrane fouling and reducing land use. However, adsorbents typically are only injected into the membrane tank once, resulting in a single dynamic protection layer and low removal efficiency over long-term operation. In addition, the granular adsorbents used can cause membrane surface damage. To overcome these disadvantages, we injected inexpensive and loose aluminum (Al)-based flocs directly into a membrane tank with bottom aeration in the presence of humic acid (HA) or raw water taken from the Miyun Reservoir (Beijing, China). Results showed that the flocs were well suspended in the membrane tank, and multiple dynamic floc protection layers were formed (sandwich-like) on the membrane surface with multiple batch injections. Higher frequency floc injections resulted in better floc utilization efficiency and less severe membrane fouling. With continuous injection, acid solutions demonstrated better performance in removing HA molecules, especially those with small molecular weight, and in alleviating membrane fouling compared with the use of high aeration rate or polyacrylamide injection. This was attributed to the small particle size, large specific surface area, and high zeta potential of the flocs. Additionally, excellent UF membrane performance was exhibited by reservoir water with continuous injection and acid solution. Based on the outstanding UF membrane performance, this innovative integrated filtration with loose Al-based flocs has great application potential for water treatment. Copyright © 2018 Elsevier Ltd. All rights reserved.

  19. Ion binding by humic and fulvic acids: A computational procedure based on functional site heterogeneity and the physical chemistry of polyelectrolyte solutions

    International Nuclear Information System (INIS)

    Marinsky, J.A.; Reddy, M.M.; Ephraim, J.; Mathuthu, A.

    1988-04-01

    Ion binding equilibria for humic and fulvic acids are examined from the point of view of functional site heterogeneity and the physical chemistry of polyelectrolyte solutions. A detailed explanation of the potentiometric properties of synthetic polyelectrolytes and ion-exchange gels is presented first to provide the basis for a parallel consideration of the potentiometric properties exhibited by humic and fulvic acids. The treatment is then extended to account for functional site heterogeneity. Sample results are presented for analysis of the ion-binding reactions of a standard soil fulvic acid (Armadale Horizons Bh) with this approach to test its capability for anticipation of metal ion removal from solution. The ultimate refined model is shown to be adaptable, after appropriate consideration of the heterogeneity and polyelectrolyte factors, to programming already available for the consideration of ion binding by inorganics in natural waters. (orig.)

  20. Nitrogenous and phosphorus excretions in juvenile silver catfish (Rhamdia quelen) exposed to different water hardness, humic acid, and pH levels.

    Science.gov (United States)

    Golombieski, Jaqueline Ineu; Koakoski, Gessi; Becker, Alessandra Janaína; Almeida, Ana Paula Gottlieb; Toni, Cândida; Finamor, Isabela Andres; Pavanato, Maria Amália; de Almeida, Tielle Moraes; Baldisserotto, Bernardo

    2013-08-01

    This study examined ammonia, urea, creatinine, protein, nitrite, nitrate, and phosphorus (P) excretion at different water hardness, humic acid, or pH levels in silver catfish (Rhamdia quelen) juveniles. The fish were exposed to different levels of water hardness (4, 24, 50, or 100 mg L(-1) CaCO3), humic acid (0, 2.5, or 5.0 mg L(-1)), or pH (5.0, 6.0, 7.0, 8.0, or 9.0) for 10 days. The overall measured nitrogen excretions were 88.1% (244-423 μmol kg(-1 )h(-1)) for ammonia, 10.9% (30-52 μmol kg(-1 )h(-1)) for creatinine, 0.02% (0.05-0.08 μmol kg(-1 )h(-1)) for protein, 0.001 % (0.002-0.004 μmol kg(-1 )h(-1)) for urea, 0.5% (0.64-3.6 μmol kg(-1 )h(-1)) for nitrite, and 0.5% (0.0-6.9 μmol kg(-1 )h(-1)) for nitrate, and these proportions were not affected by water hardness or humic acid levels. The overall P excretion in R. quelen was 0.14-2.97 μmol kg(-1) h(-1). Ammonia excretion in R. quelen usually was significantly higher in the first 12 h after feeding, and no clear effect of water hardness, humic acid levels, and pH on this daily pattern of ammonia excretion could be observed. Water hardness only affected the ammonia and P excretion of R. quelen juveniles in the initial and fifth days after transfer, respectively. The exposure of this species to humic acid increased ammonia excretion after 10 days of exposure but did not affect P excretion. An increase in pH decreased ammonia and increased creatinine excretion but did not change P excretion in R. quelen. Therefore, when there is any change on humic acid levels or pH in the culture of this species, nitrogenous compounds must be monitored because their excretion rates are variable. On the other hand, P excretion rates determined in the present study are applicable to a wide range of fish culture conditions.

  1. Greensporones: resorcylic acid lactones from an aquatic Halenospora sp.

    Science.gov (United States)

    El-Elimat, Tamam; Raja, Huzefa A; Day, Cynthia S; Chen, Wei-Lun; Swanson, Steven M; Oberlies, Nicholas H

    2014-09-26

    Fourteen new resorcylic acid lactones (1-14) were isolated from an organic extract of a culture of a freshwater aquatic fungus Halenospora sp. originating from a stream in North Carolina. The structures were elucidated using a set of spectroscopic and spectrometric techniques. The absolute configuration of one representative member of the compounds (7) was assigned using X-ray crystallography of an analogue that incorporated a heavy atom, whereas for compounds 8-11, a modified Mosher's ester method was utilized. The relative configurations of compounds 12-14 were determined on the basis of NOE data. Compounds 12-14 were proposed as artifacts produced by intramolecular cycloetherification of the ε-hydroxy-α,β-unsaturated ketone moieties of the parent compounds during the purification processes. The isolated compounds, except for 8 and 12, were tested against the MDA-MB-435 (melanoma) and HT-29 (colon) cancer cell lines. Compound 5 was the most potent, with IC50 values of 2.9 and 7.5 μM, respectively. The compounds were evaluated as TAK1-TAB1 inhibitors but were found to be inactive.

  2. Interaction of Fe(II) with Polyacrylic Acid as a Simplification of Humic Acid: Comparison of Ion Exchange and Solvent Extraction Methods

    International Nuclear Information System (INIS)

    Budi Setiawan

    2007-01-01

    To estimate the safety assessment around the disposal facility, the interaction behavior of radionuclides/metal ions into organic material (such as humic acids) exist in natural water becomes an important study. To avoid the effect of heterogeneous composition of humic acid, polyacrylic acids (abbrev. APA) was used as are representative of homogeneous polymeric weak acid. The experiments have been carried out by solvent extraction and ion exchange methods to find out the suitable method for the study of complex formation of Fe(II) with humic acid(AH) and APA. The solvent extraction experiment has been done by using diphenylthiocarbazone (dithizone) in CCl 4 and C Fe(II) were 10 -8 M to 10 -5 M, pH around 5 and I=0.1M NaCI. In ionic exchange experiment, C Fe(II) were 10 -8 to 10 -4 M, pH from 4.8 to 5.5 in I=0.1M NaCl. The apparent complex formation constant is defined as β α = [ML]/([M][R]), where [M] and [ML] are concentration of free and bound of Fe(II) and [R] is the concentration of dissociated carboxylic group in macromolecules of PAA. The results shown that, for solvent extraction experiments, variable concentration of Fe(II) had no appreciable influence on the distribution ratio of Fe(II)-polyacrylate at the tracer concentration with the log D to be 1.32 ± 0.03 (pcH 5.25). At macro concentration, the distribution ratio of Fe(II) becomes smaller due to oxidation and obtained log D value to be 1.04 ± 0.07 (pcH 5.34). An interest kind was observed at higher PAA concentration, the distribution ratio curve becomes higher presumably due to the problem on redox sensitive characteristic of Fe(II) and/or coagulation of Fe(II)-polyacrylate at the interface of aqueous-organic phases. In case of ionic exchange method, the plot of I/Kd versus [R] gives a straight line result indicating this method is appropriate and more superior compare than solvent extraction method to determine the complex formation constant. (author)

  3. Phosphorus in chronosequence of burnt sugar cane in Brazilian cerrado: humic acid analysis by {sup 31}P NMR; Fosforo em cronossequencia de cana-de-acucar queimada no cerrado goiano: analise de acidos humicos por RMN de {sup 31}P

    Energy Technology Data Exchange (ETDEWEB)

    Rossi, Celeste Q.; Pereira, Marcos G.; Garcia, Andreas C., E-mail: mgervasiopereira@gmail.com [Universidade Federal Rural do Rio de Janeiro (UFRRJ), Seropedica, RJ (Brazil). Dept. de Solos; Perin, Adriano; Gazolla, Paulo R. [Instituto Federal de Educacao, Ciencia e Tecnologia Goiano, Rio Verde, GO (Brazil); Gonzalez, Antonio P. [Universidade de Coruna, ES (Spain). Faculdad de Ciencias

    2013-10-01

    The aim of this study was to identify, with the use of {sup 31}P NMR spectroscopy, organic P species in humic acids (HA) in samples from Oxisol cultivated in chronosequence with sugar cane, pasture and Cerrado. The main forms of P-type found were orthophosphate, monoester-P (phosphate sugars) and P-diester (orthophosphate). The {sup 31}P NMR technique proved capable of identifying changes in the areas studied as a function of sugar cane burning time. In areas with 1 and 5 years of burnt cane, a decrease in recalcitrant organic P in humic acids indicated the need for use of P-humic substances for plant nutrition (author)

  4. Melanin and humic acid-like polymer complex from olive mill waste waters. Part I. Isolation and characterization.

    Science.gov (United States)

    Khemakhem, Maissa; Papadimitriou, Vassiliki; Sotiroudis, Georgios; Zoumpoulakis, Panagiotis; Arbez-Gindre, Cécile; Bouzouita, Nabiha; Sotiroudis, Theodore G

    2016-07-15

    A water soluble humic acid and melanin-like polymer complex (OMWW-ASP) was isolated from olive mill waste waters (OMWW) by ammonium sulfate fractionation to be used as natural additive in food preparations. The dark polymer complex was further characterized by a variety of biochemical, physicochemical and spectroscopic techniques. OMWW-ASP is composed mainly of proteins associated with polyphenols and carbohydrates and the distribution of its relative molecular size was determined between about 5 and 190 kDa. SDS-PAGE shows the presence of a well separated protein band of 21.3 kDa and a low molecular weight peptide. The OMWW-ASP complex exhibits a monotonically increasing UV-Vis absorption spectrum and it contains stable radicals. Antioxidant activity measurements reveal the ability of the OMWW protein fraction to scavenge both the cationic 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS(+)) radical, as well as the stable nitroxide free radical 4-hydroxy-2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPOL). Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. DETERMINATION OF RATE CONSTANT AND STABILITY OF ADSORPTION IN COMPETITIVE ADSORPTION OF Cr(III AND Cd(II ON HUMIC ACID BY USING THE NEW MODEL OF KINETIC FORMULATION

    Directory of Open Access Journals (Sweden)

    Suyanta Suyanta

    2010-06-01

    Full Text Available Determination of rate and stability constants of adsorption in competitive adsorption of Cr(III and Cd(II on humic acid by using the new model of kinetic formulation has been done. The new model based on assumption that those adsorption was first order adsorption rearched equilibrium. Humic acid was isolated from Peat moss of Silaut- West Sumatra by modificated Schnitzer method. Humic acid characterization was conducted by using infrared spectrophotometer with KBR pellet method. The experiment of kinetic adsorption was conducted in batch system reactor using erlenmeyer at 25 ± 0.01 oC of water steam bath and in a series of sampling procedure. Initial concentration of both Cr(III and Cd(II was 4x10-4 M. Thirty milligrams of humic acid was added to 200 mL of metal solution, and then stirred continuously. At the fixed periode of time, 10 mL of sample was taken using a syringe, then filterd with 0.45 µm filter paper. Concentration of Cr(III and Cd(II in the filtrate was determinated by AAS, while that was adsorbed by humic acid was equal to difference between initial and equilibrium concentration. It was concluded that competitive adsorption of Cr(III and Cd(II on humic acid was first order adsorption rearched equilibrium as proposed in this research. Adsorption rate constant of Cr(III on humic acid  at competitive condition was greater than of Cd(II, but on the contrary for stability constant (K. Competition between Cr(III and Cd(II to interact with the active side of humic acid was dominated by Cr(III.   Keywords: rate constant, stability and competitive adsorption

  6. Effects of iron nanoparticles and humic acid on growth, development and vase life of cut rose flower cv. White Nablus under hydroponic conditions

    OpenAIRE

    H. Bagi; E. Chamani

    2016-01-01

    To evaluate the effects of different concentrations of iron nanoparticles (10, 100, 1000 and 2000 mg/L) and humic acid (100, 1000 and 2000 mg/L) on growth, flowering and characteristics of cut rose flower, cultivar White Nablus, under hydroponic system, an experiment was conducted based on completely randomized design with factorial arrangement and 5 replications in the Research Greenhouse of Mohaghegh Ardabili University in 2012-2013. Nutrient solution, formulated by Van Zinder and Baker, wa...

  7. The Effect of Humic Acid Applications on Some Morphological, Physiological and Biochemical Characteristics of Eggplants Irrigated with Water Contained Heavy Metals in High Concentration

    OpenAIRE

    Sevinc Kiran; Fatma Özkay; Kuşvuran Şebnem; Ellialtıoğlu Şebnem

    2014-01-01

    In this study, it was aimed to demonstrate the effect of humic acid applications on some morphological, physiological and biochemical characteristics of eggplant genotypes (Burdur Merkez, Burdur Bucak, Kemer and Giresun) irrigated with the irrigation water with a high content of heavy metal and determined previously salt tolerance levels. In studies conducted in controlled greenhouse conditions, eggplant seeds germinated in the growth substrate a mixture of peat and perlite and the seedlings ...

  8. Potential effects of rainwater-borne H2O2on competitive degradation of herbicides and in the presence of humic acid.

    Science.gov (United States)

    Qin, Junhao; Li, Yongjun; Li, Shengan; Li, Huashou; Lin, Chuxia

    2017-03-01

    In a previous piece of work, we reported some preliminary experimental results showing that hydrogen peroxide at a concentration range frequently encountered in rainwater could lead to degradation of three common herbicides (diuron, butachlor and glyphosate). However, the work was limited to the observation on the effects of Fenton process on the individual herbicides. In field conditions, different types of herbicides along with other organic molecules may occur concurrently. It is unclear how different herbicides and various organic molecules compete for the available hydroxyl radical. In this study, further laboratory experiments were conducted to observe the changes in the herbicides in the scenarios where multiple herbicides or humic acid are present. The results show that humic acid impeded hydroxyl radical-driven degradation of the diuron and butachlor. However, humic acid had no significant effects on reducing glyphosate removal rate. Glyphosate could compete strongly with the humic acid for the available hydroxyl radical in the reaction systems. The reactivity of glyphosate with hydroxyl radical was much higher than those of diuron and butachlor due possibly to its relatively simpler chemical structure, as compared to either diuron or butachlor, which are aromatic compounds that have higher chemical stability. Butachlor degradation was much weaker in the combined diuron and butachlor system than in the combined glyphosate and butachlor system. In the glyphosate-butachlor system, the opposite was observed. The findings have moved another step forward to understanding the potential role of rainwater-borne H 2 O 2 in degrading herbicides in open water environments. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Humic acid-bonded silica as a novel sorbent for solid-phase extraction of benzo[a]pyrene in edible oils

    International Nuclear Information System (INIS)

    Luo Dan; Yu Qiongwei; Yin Hongrui; Feng Yuqi

    2007-01-01

    A novel solid-phase extraction (SPE) sorbent, humic acid-bonded silica (HAS), was prepared. Humic acids (HAs) were grafted onto silica matrices via an amide linkage between humyl chloride and the amido terminus of 3-aminopropyltrimethoxysilane (APTS)-silica gel. The resulting material was characterized by Fourier transform infrared spectrometer, elemental analysis, and nitrogen adsorption analysis. This sorbent exhibits an excellent adsorption capacity for some electron-abundant analytes owing to its peculiar structure. In this paper, we choose benzo[a]pyrene (BaP) in oil as a probe to validate the adsorption capacity of the material. Thus a fast, cheap and simple SPE method with humic acid-bonded silica cartridge for edible oil clean-up, followed by high-performance liquid chromatography (HPLC) with fluorescence detection was established. The effects of experimental variables, such as washing and elution solvents, and the amount of sorbents have been studied. The recoveries of BaP in edible oils spiked at 0.2-100 μg kg -1 were in the range of 78.8-102.7% with relative standard deviations ranging between 1.3 and 9.3%; the limit of detection was -0.06 μg kg -1

  10. Effect of humic acid on the toxicity of bare and capped ZnO nanoparticles on bacteria, algal and crustacean systems.

    Science.gov (United States)

    Akhil, K; Sudheer Khan, S

    2017-02-01

    Zinc oxide nanoparticles are one of the most extensively used nanoparticles in various commercial products. Depending on the purpose, the particles are coated with various agents including poly vinyl pyrrolidone, poly vinyl alcohol, ethylene glycol etc. As the particles are heavily used, the chance of the particles to get run off into the environment is very high. The study explains the difference in toxicity of bare and capped zinc oxide nanoparticles under various environmental conditions including humic acid and visible light against bacterial, algal and crustacean system. Staphylococcus aureus and Pseudomonas aeruginosa were used as model system for bacterial toxicity testing. Plate counting assay was employed for assessing the toxicity against bacteria. Chlorella pyrenoidsa was used for studying toxicity against algal system, which was evaluated using the chlorophyll estimation assay. Daphnia sp. was used for studying the toxicity in crustacean system. The particles had the ability to adsorb humic acid which further affected the stability of the particle. The study concludes that the presence of environmental factors including humic acid affects the toxicological nature of ZnO NPs. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Hydroxypropyl-β-cyclodextrin extractability and bioavailability of phenanthrene in humin and humic acid fractions from different soils and sediments.

    Science.gov (United States)

    Gao, Huipeng; Ma, Jing; Xu, Li; Jia, Lingyun

    2014-01-01

    Organic matter (OM) plays a vital role in controlling polycyclic aromatic hydrocarbon (PAH) bioavailability in soils and sediments. In this study, both a hydroxypropyl-β-cyclodextrin (HPCD) extraction test and a biodegradation test were performed to evaluate the bioavailability of phenanthrene in seven different bulk soil/sediment samples and two OM components (humin fractions and humic acid (HA) fractions) separated from these soils/sediments. Results showed that both the extent of HPCD-extractable phenanthrene and the extent of biodegradable phenanthrene in humin fraction were lower than those in the respective HA fraction and source soil/sediment, demonstrating the limited bioavailability of phenanthrene in the humin fraction. For the source soils/sediments and the humin fractions, significant inverse relationships were observed between the sorption capacities for phenanthrene and the amounts of HPCD-extractable or biodegradable phenanthrene (p humin fractions, with both slopes close to 1. On the other hand, in the case of phenanthrene contained in HA, a poor relationship was observed between the amount of phenanthrene extracted by HPCD and the amount degraded, with the former being much less than the latter. The results revealed the importance of humin fraction in affecting the bioavailability of phenanthrene in the bulk soils/sediments, which would deepen our understanding of the organic matter fractions in affecting desorption and biodegradation of organic pollutants and provide theoretical support for remediation and risk assessment of contaminated soils and sediments.

  12. Phenanthrene sorption to humic acids, humin, and black carbon in sediments from typical water systems in China.

    Science.gov (United States)

    Zhang, Jinghuan; He, Mengchang; Lin, Chunye; Shi, Yehong

    2010-07-01

    Humic acid (HA) and humin (HM) were extracted with 0.1 M NaOH and black carbon (BC) was isolated using a combustion method at 375 degrees C from six sediments in different areas in China and their sorption isotherms for phenanthrene (Phen) were determined. All sorption isotherms were nonlinear and fitted well with the Freundlich model. Among the SOM, HM and BC with more aromatic carbon controlled the sorption nonlinearity and capacity. Compared to HM, higher K (oc) values were observed for BC due to the combustion of organic matter and native sorbates in HM. For HAs isotherms, a positive relation was observed between the K (oc) values and aliphaticity or H/C ratios, but a negative relation was shown between the n values and polarity of HAs. HA, HM, and BC were responsible for 0.4-9.3%, 46-97%, and 65-96% of the total sorption, respectively, indicating the dominance of HM and BC fractions in overall sorption of Phen by the sediments.

  13. Enhanced removal of humic acid from aqueous solution by novel stabilized nano-amorphous calcium phosphate: Behaviors and mechanisms

    Science.gov (United States)

    Jiang, Ling; Li, Yiming; Shao, Yi; Zhang, Yong; Han, Ruiming; Li, Shiyin; Wei, Wei

    2018-01-01

    Stabilized nano-amorphous calcium phosphate (nACP) was prepared using polyethylene glycol as stabilizer to obtain a nanosized amorphous adsorbent. The produced nACP was evaluated by using XRD, FTIR, SEM and X-ray photoelectron spectroscopy (XPS). The sedimentation test demonstrated that nACP exhibited better stability than crystallized hydroxyapatite. The adsorption efficiency of the nACP material for aqueous humic acid (HA) was evaluated from the point of view of medium pH, adsorption time, temperature, and ionic strength, as well as the presences of metal ions. The results of the study showed very good adsorption performance towards aqueous HA. The Sips modeling results revealed that the stabilized nACP adsorbent had a considerably high adsorption capacity (248.3 mg/g) for HA at 298 K. The adsorption data fitted well into pseudo-second order and Elovich kinetic models. XPS analyses indicated that HA retention on nACP material might be due to the surface complexation reaction between oxygen-containing group and calcium of HA and nACP, respectively. Moreover, the HA adsorption capacity of nACP could still keep more than 86% after four adsorption-desorption cycles. By taking into account all results it was concluded that the nACP adsorbent leveraged its stability in combination with its high uptake capacity to offer a great promise for HA adsorption from water.

  14. Synergy between surface adsorption and photocatalysis during degradation of humic acid on TiO2/activated carbon composites

    International Nuclear Information System (INIS)

    Xue Gang; Liu Huanhuan; Chen Quanyuan; Hills, Colin; Tyrer, Mark; Innocent, Francis

    2011-01-01

    A photocatalyst comprising nano-sized TiO 2 particles on granular activated carbon (GAC) was prepared by a sol-dipping-gel process. The TiO 2 /GAC composite was characterized by scanning electron microscopy (SEM), X-ray diffractiometry (XRD) and nitrogen sorptometry, and its photocatalytic activity was studied through the degradation of humic acid (HA) in a quartz glass reactor. The factors influencing photocatalysis were investigated and the GAC was found to be an ideal substrate for nano-sized TiO 2 immobilization. A 99.5% removal efficiency for HA from solution was achieved at an initial concentration of 15 mg/L in a period of 3 h. It was found that degradation of HA on the TiO 2 /GAC composite was facilitated by the synergistic relationship between surface adsorption characteristics and photocatalytic potential. The fitting of experimental results with the Langmuir-Hinshelwood (L-H) model showed that the reaction rate constant and the adsorption constant values were 0.1124 mg/(L min) and 0.3402 L/mg. The latter is 1.7 times of the calculated value by fitting the adsorption equilibrium data into the Langmuir equation.

  15. Combined photo-Fenton and biological treatment for Diuron and Linuron removal from water containing humic acid

    International Nuclear Information System (INIS)

    Farre, Maria Jose; Domenech, Xavier; Peral, Jose

    2007-01-01

    A combined chemical (photo-Fenton) and biological treatment has been proposed for Diuron and Linuron degradation in water containing natural dissolved organic matter (DOM). Humic acid (HA) was used to simulate the DOM. During the photo-Fenton process ([Fe(II)]=15.9mgL -1 , [H 2 O 2 ]=202mgL -1 , 60min of UVA irradiation time), the chemical oxygen demand (COD), total organic carbon (TOC), toxicity (EC 50 15 ) and biodegradability (BOD 5 /COD) of the generated intermediates were assessed. A reduction of photo-Fenton efficiency was observed when HA was present in solution. This effect has been explained as the result of a UVA light screening as well as a OH? radical quenching process by the HA. After the photo-Fenton process, the initial toxic and non-biodegradable herbicides were transformed into intermediates suitable for a subsequent aerobic biological treatment that was performed in a sequencing batch reactor (SBR). Complete elimination of the intermediates in presence of HA was reached at the end of the chemical-biological coupled system. Biosorption of HA onto the aerobic biomass was characterized. The results indicate that the Freundlich model adequately describes the adsorption of HA, a phenomena that follows a pseudo second-order adsorption kinetic model

  16. Combined photo-Fenton and biological treatment for Diuron and Linuron removal from water containing humic acid

    Energy Technology Data Exchange (ETDEWEB)

    Farre, Maria Jose [Departament de Quimica, Universitat Autonoma de Barcelona, 08193 Bellaterra (Spain); Domenech, Xavier [Departament de Quimica, Universitat Autonoma de Barcelona, 08193 Bellaterra (Spain); Peral, Jose [Departament de Quimica, Universitat Autonoma de Barcelona, 08193 Bellaterra (Spain)]. E-mail: jose.peral@uab.es

    2007-08-17

    A combined chemical (photo-Fenton) and biological treatment has been proposed for Diuron and Linuron degradation in water containing natural dissolved organic matter (DOM). Humic acid (HA) was used to simulate the DOM. During the photo-Fenton process ([Fe(II)]=15.9mgL{sup -1}, [H{sub 2}O{sub 2}]=202mgL{sup -1}, 60min of UVA irradiation time), the chemical oxygen demand (COD), total organic carbon (TOC), toxicity (EC{sub 50}{sup 15}) and biodegradability (BOD{sub 5}/COD) of the generated intermediates were assessed. A reduction of photo-Fenton efficiency was observed when HA was present in solution. This effect has been explained as the result of a UVA light screening as well as a OH? radical quenching process by the HA. After the photo-Fenton process, the initial toxic and non-biodegradable herbicides were transformed into intermediates suitable for a subsequent aerobic biological treatment that was performed in a sequencing batch reactor (SBR). Complete elimination of the intermediates in presence of HA was reached at the end of the chemical-biological coupled system. Biosorption of HA onto the aerobic biomass was characterized. The results indicate that the Freundlich model adequately describes the adsorption of HA, a phenomena that follows a pseudo second-order adsorption kinetic model.

  17. EXAFS investigations of the interaction of humic acids and model compounds with uranyl cations in solid complexes

    International Nuclear Information System (INIS)

    Denecke, M.A.; Reich, T.; Pompe, S.; Bubner, M.; Heise, K.H.; Nitsche, H.; Allen, P.G.; Bucher, J.J.; Edelstein, N.M.; Shuh, D.K.; Czerwinski, K.R.

    1998-01-01

    Natural humic acids, HA's, having varying amounts of their proton exchange capacities, PEC's, loaded with uranyl ions and synthetic HA loaded with 14% PEC were prepared either from solution or from suspension. The interaction of uranium with the humates was studied using U L III -edge extended X-ray absorption fine structure, EXAFS, and infrared, IR, spectroscopy. IR results indicate a direct complexation of the uranyl ions onto the HA's. The spectral positions of the asymmetric and symmetric IR stretching frequencies for COO - in the complex suggest monodentate coordination of HA carboxylate groups onto the uranyl cation. In all samples studied, the EXAFS analysis yielded axial uranium-oxygen distances of 1.77-1.78 A and five oxygen atoms in the plane equatorial to the uranyl unit at distances of 2.37-2.39 A. The bond distances determined from the EXAFS are the same, within the experimental error, for both synthetic and two different natural uranyl humates, for samples with large loadings and samples with relatively low uranyl loadings, as well as for dry and wet paste samples. Comparison of the EXAFS from the uranyl humates with that observed for two crystalline uranyl carboxylate complexes indicates that the HA carboxylate groups act predominantly as monodentate ligands when bound to the uranyl unit. Additional, neutral ligands must also be coordinated to the uranyl ion in order to satisfy the uranyl cation coordination number determined as 5 ± 0.7. (orig.)

  18. Effect of Humic Acid on As Redox Transformation and Kinetic Adsorption onto Iron Oxide Based Adsorbent (IBA

    Directory of Open Access Journals (Sweden)

    Hoda Fakour

    2014-10-01

    Full Text Available Due to the importance of adsorption kinetics and redox transformation of arsenic (As during the adsorption process, the present study elucidated natural organic matter (NOM effects on As adsorption-desorption kinetics and speciation transformation. The experimental procedures were conducted by examining interactions of arsenate and arsenite with different concentrations of humic acid (HA as a model representative of NOM, in the presence of iron oxide based adsorbent (IBA, as a model solid surface in three environmentally relevant conditions, including the simultaneous adsorption of both As and HA onto IBA, HA adsorption onto As-presorbed IBA, and As adsorption onto HA-presorbed IBA. Experimental adsorption-desorption data were all fitted by original and modified Lagergren pseudo-first and -second order adsorption kinetic models, respectively. Weber’s intraparticle diffusion was also used to gain insight into the mechanisms and rate controlling steps, which the results suggested that intraparticle diffusion of As species onto IBA is the main rate-controlling step. Different concentrations of HA mediated the redox transformation of As species, with a higher oxidation ability than reduction. The overall results indicated the significant effect of organic matter on the adsorption kinetics and redox transformation of As species, and consequently, the fate, transport and mobility of As in different environmentally relevant conditions.

  19. Differential roles of humic acid and particulate organic matter in the equilibrium sorption of atrazine by soils.

    Science.gov (United States)

    Yu, Zhiqiang; Sharma, Samriti; Huang, Weilin

    2006-08-01

    Recent studies have indicated that soil organic matter (SOM) may consist of physically and chemically different fractions, including particulate organic matter (POM), such as black carbon and unburned coal materials. The present study examined the differential roles of three different SOM fractions isolated from a peat and a topsoil in the equilibrium sorption of the herbicide atrazine (ATZ). The SOM fractions isolated from the two samples included humic acids (HAs), base-extracted humin (HM), and POM after demineralization of HM. A batch technique was employed to measure both the nonequilibrium ATZ sorption on the original and HA samples and the equilibrium ATZ sorption and desorption. The results showed that the phase-distribution relationships measured under nonequilibrium conditions were more linear and had lower sorption-capacity parameters compared with their respective isotherms measured under equilibrium conditions. The sorption isotherms were variously nonlinear, with POM exhibiting the greatest organic carbon-normalized sorption capacity. There existed apparent sorption-desorption hysteresis for each sorbent-sorbate system. It appeared that the extracted HAs could facilitate hydrolysis of ATZ when the reaction time extended to 4 d or longer. The equilibrium sorptive behavior of the HAs therefore was not examined. The present study indicated that both original samples showed lower organic carbon-normalized sorption distribution coefficients compared with their respective SOM fractions, suggesting that a fraction of sorption sites in soil aggregates were not accessed by ATZ.

  20. Effect of the chemical structure of anion exchange resin on the adsorption of humic acid: behavior and mechanism.

    Science.gov (United States)

    Shuang, Chendong; Wang, Jun; Li, Haibo; Li, Aimin; Zhou, Qing

    2015-01-01

    Polystyrenic (PS) anion-exchange resin and polyacrylic (PA) anion-exchange resin were used to investigate the effect of resin chemical structure on the adsorption of humic acid (HA). Due to the rearrangement of HA to form layers that function as barricades to further HA diffusion, PS resin exhibited 12.4 times slower kinetics for the initial adsorption rate and 8.4 times for the diffusion constant in comparison to that of the PA resin. An HA layer and a spherical cluster of HA can be observed on the surface of the PS and PA resins after adsorption, respectively. The considerable difference in HA adsorption between the PS and PA resins was due to the difference in molecule shape for interaction with different resin structures, which can essentially be explained by the hydrophobicity and various interactions of the PS resin. A given amount of HA occupies more positively charged sites and hydrophobic sites on the PS resin than were occupied by the same amount of HA on the PA resin. Increased pH resulted in an increase of HA adsorption onto the PA resin but a decrease in adsorption onto PS resin, as the non-electrostatic adsorption led to electrostatic repulsion between the HA attached to the resin and the HA dissolved in solution. These results suggest higher rates of adsorption and higher regeneration efficiency for interaction of HA with more hydrophilic anion exchange materials. Copyright © 2014 Elsevier Inc. All rights reserved.

  1. Induction of Systematic Resistance in Soybean Plants against Fusarium Wilt Disease by Seed Treatment with Benzothiadiazole and Humic Acid

    Directory of Open Access Journals (Sweden)

    Montaser Fawzy ABDEL-MONAIM

    2011-05-01

    Full Text Available The ability of benzothiadiazole (BTH, humic acid (HA and their combination when used as seed soaking to induce systemic resistance against a pathogenic strain of Fusarium oxysporum was examined in four soybean cultivars under greenhouse conditions. Both inducers and their combination were able to protect soybean plants against damping-off and wilt diseases compared with check treatment. These results were confirmed under field conditions in two different locations i. e Minia and New Valley governorates. The tested treatments significantly reduced damping-off and wilt diseases and increased growth parameters, except number of branches plant-1, and seed yield. Application of BTH (0.25 + HA (4 g/l was the most potent in this respect treatment. Soybean seed soaking in BTH+ HA recorded the highest activities of the testes of oxidative enzymes followed by BTH in the four soybean cultivars. Whereas, HA treatment was recorded the lowest increased of these oxidative enzymes. Also, similar results were obtained in case of total phenol but HA increased the total phenol more than BTH in all tested cultivars.

  2. Chlorpyrifos-methyl solubilisation by humic acids used as bio-surfactants extracted from lignocelluloses and kitchen wastes.

    Science.gov (United States)

    Scaglia, Barbara; Baglieri, Andrea; Tambone, Fulvia; Gennari, Mara; Adani, Fabrizio

    2016-09-01

    Chlorpyrifos-methyl (CLP-m) is a widely used organophosphate insecticide that can accumulate in soil and become toxic to humans. CLP-m can be removed from soil by its solubilisation using synthetic surfactants. However, synthetic surfactants can accumulate in soil causing contamination phenomena themselves. Bio-surfactants can be used as an alternative to synthetic ones, reducing costs and environmental issues. In this work, humic acid (HA) extracted from raw biomasses, i.e. lignocelluloses (HAL) and lignocelluloses plus kitchen food waste (HALF), corresponding composts (C) (HALC and HALFC) and leonardite (HAc), were tested in comparison with commercial surfactants, i.e. SDS, Tween 20 and DHAB, to solubilize CLP-m. Results obtained indicated that only biomass-derived HA, composted biomass-derived HA, and SDS solubilized CLP-m: SDS = 0.006; HAL = 0.007; HALC = 0.009 g; HALF = 0.025; HALFC = 0.024) (g CLP-m g(-1) surfactant). Lignocelluloses HAs (HAL, HALF) solubilized CLP-m just as well as SDS while lignocellulosic plus kitchen food waste HA (HALF, HALFC) showed a three times higher CLP-m solubilisation capability. This difference was attributed to the higher concentration of alkyl-Carbon that creates strong links with CLP-m in the hydrophobic micelle-core of the surfactants. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Could humic acid relieve the biochemical toxicities and DNA damage caused by nickel and deltamethrin in earthworms (Eisenia foetida)?

    Science.gov (United States)

    Shen, Chen-Chao; Shen, Dong-Sheng; Shentu, Jia-Li; Wang, Mei-Zhen; Wan, Ming-Yang

    2015-12-01

    The aim of the study was to determine whether humic acid (HA) prevented gene and biochemical toxic effects in earthworms (Eisenia foetida) exposed to nickel and deltamethrin (at 100 and 1 mg kg(-1), respectively) in soil. Cellular- and molecular-level toxic effects of nickel and deltamethrin in earthworms were evaluated by measuring damage to lipid membranes and DNA and the production of protein carbonyls over 42 days of exposure. Nickel and deltamethrin induced significant levels of oxidative stress in earthworms, increasing the production of peroxidation products (malondialdehyde and protein carbonyls) and increasing the comet assay tail DNA% (determined by single-cell gel electrophoresis). DNA damage was the most sensitive of the three indices because it gave a higher sample/control ratio than did the other indices. The presence of HA alleviated (in decreasing order of effectiveness) damage to DNA, proteins, and lipid membranes caused by nickel and deltamethrin. A low HA dose (0.5-1% HA in soil) prevented a great deal of lipid membrane damage, but the highest HA dose (3% HA in soil) prevented still more DNA damage. However, the malondialdehyde concentrations in earthworms were higher at the highest HA dose than at the lower HA doses. The amounts of protein carbonyls produced at different HA doses were not significantly different. The toxic effects to earthworms caused by increased oxidizable nickel concentrations could be relieved by adding HA.

  4. Influences of humic acid on the bioavailability of phenanthrene and alkyl phenanthrenes to early life stages of marine medaka (Oryzias melastigma)

    International Nuclear Information System (INIS)

    Liu, Yangzhi; Yang, Chenghu; Cheng, Pakkin; He, Xiaojing; Zhu, Yaxian; Zhang, Yong

    2016-01-01

    The influences of humic acid (HA) on the environmental behavior and bioavailability of parent polycyclic aromatic hydrocarbons (PAHs) and alkyl PAHs were investigated and compared using the early life stages of marine medaka (Oryzias melastigma, O. melastigma). It was demonstrated that the binding affinity of parent phenanthrene (PHE) with HA was smaller than that of 3-methyl phenanthrene (3-MP) and 9-ethyl phenanthrene (9-EP). Furthermore, the bioaccumulation of the three PAHs and the levels of lipid peroxidation (LPO) were calculated to study the changes in bioavailability of PAHs in presence of HA. The results indicated that the addition of HA significantly decreased the bioaccumulation and toxicity of PAHs by decreasing free PAHs concentrations. The bioavailable fractions of HA-bound PAHs in bioaccumulation (α) and toxicity (β) were evaluated, indicating that the HA-bound 3-MP and 9-EP show higher bioavailability in bioaccumulation and lower bioavailability in toxicity relative to those of PHE. The β/α values were less than 1 for all PAH treatment groups containing HA, suggesting that the fraction of HA-bound PAHs contributing to bioaccumulation was higher than that of HA-bound PAHs inducing toxic effect. In addition, we proposed that the free PAHs generated by desorption from HA in the cell were toxic by showing that the β/α ratio values are correlated with the log K OW values (p = 0.007 and R 2  = 0.8355). Thus, oil spill risk assessments should consider both alkyl PAHs and the factors that influence the bioavailability and toxicity of PAHs in the natural aquatic environments. - Highlights: • Effects of HA on bioavailability of parent and alkyl PAHs were firstly compared. • Changes in the bioavailability due to HA depended on the alkylation of PAHs. • The bioavailable fractions of the HA-bound parent and alkyl PAHs were calculated. • The toxicity of HA-bound PAHs was related to the physicochemical properties of PAHs. - This study is the

  5. Humic acid adsorption onto cationic cellulose nanofibers for bioinspired removal of copper( ii ) and a positively charged dye

    KAUST Repository

    Sehaqui, H.

    2015-01-01

    © The Royal Society of Chemistry. Waste pulp residues are herein exploited for the synthesis of a sorbent for humic acid (HA), which is a major water pollutant. Cellulose pulp was etherified with a quaternary ammonium salt in water thereby introducing positive charges onto the surface of the pulp fibers, and subsequently mechanically disintegrated into high surface area cellulose nanofibers (CNF). CNF with three different charge contents were produced and their adsorption capacity towards HA was investigated with UV-spectrophotometry, quartz crystal microbalance with dissipation, and ζ-potential measurements. Substantial coverage of the CNF surface with HA in a wide pH range led to a reversal of the positive ζ-potentials of CNF suspensions. The HA adsorption capacity and the kinetics of HA uptake were found to be promoted by both acidic pH conditions and the surface charge content of CNF. It is suggested that HA adsorption onto CNF depends on electrostatic interactions between the two components, as well as on the conformation of HA. At pH ∼ 6, up to 310 mg g-1 of HA were adsorbed by the functionalized CNF, a substantially higher capacity than that of previously reported HA sorbents in the literature. It is further shown that CNF-HA complexes could be freeze-dried into "soil-mimicking" porous foams having good capacity to capture Cu(ii) ions and positive dyes from contaminated water. Thus, the most abundant natural polymer, i.e., cellulose could effectively bind the most abundant natural organic matter for environmental remediation purpose.

  6. Secondary Structures in a Freeze-Dried Lignite Humic Acid Fraction Caused by Hydrogen-Bonding of Acidic Protons with Aromatic Rings.

    Science.gov (United States)

    Cao, Xiaoyan; Drosos, Marios; Leenheer, Jerry A; Mao, Jingdong

    2016-02-16

    A lignite humic acid (HA) was separated from inorganic and non-HA impurities (i.e., aluminosilicates, metals) and fractionated by a combination of dialysis and XAD-8 resin. Fractionation revealed a more homogeneous structure of lignite HA. New and more specific structural information on the main lignite HA fraction is obtained by solid-state nuclear magnetic resonance (NMR) spectroscopy. Quantitative (13)C multiple cross-polarization (multiCP) NMR indicated oxidized phenyl propane structures derived from lignin. MultiCP experiments, conducted on potassium HA salts titrated to pH 10 and pH 12, revealed shifts consistent with carboxylate and phenolate formation, but structural changes associated with enolate formation from aromatic beta keto acids were not detected. Two-dimensional (1)H-(13)C heteronuclear correlation (2D HETCOR) NMR indicated aryl-aliphatic ketones, aliphatic and aromatic carboxyl groups, phenol, and methoxy phenyl ethers. Acidic protons from carboxyl groups in both the lignite HA fraction and a synthetic HA-like polycondensate were found to be hydrogen-bonded with electron-rich aromatic rings. Our results coupled with published infrared spectra provide evidence for the preferential hydrogen bonding of acidic hydrogens with electron-rich aromatic rings rather than adjacent carbonyl groups. These hydrogen-bonding interactions likely result from stereochemical arrangements in primary structures and folding.

  7. Humic substances can modulate the allelopathic potential of caffeic, ferulic, and salicylic acids for seedlings of lettuce (Lactuca sativa L.) and tomato (Lycopersicon esculentum Mill.).

    Science.gov (United States)

    Loffredo, Elisabetta; Monaci, Linda; Senesi, Nicola

    2005-11-30

    The capacity of a leonardite humic acid (LHA), a soil humic acid (SHA), and a soil fulvic acid (SFA) in modulating the allelopathic potential of caffeic acid (CA), ferulic acid (FA), and salicylic acid (SA) on seedlings of lettuce (Lactuca sativa L.) and tomato (Lycopersicon esculentum Mill.) was investigated. Lettuce showed a sensitivity greater than that of tomato to CA, FA, and SA phytotoxicity, which was significantly reduced or even suppressed in the presence of SHA or SFA, especially at the highest dose, but not LHA. In general, SFA was slightly more active than SHA, and the efficiency of the action depended on their concentration, the plant species and the organ examined, and the allelochemical. The daily measured residual concentration of CA and FA decreased drastically and that of SA slightly in the presence of germinating seeds of lettuce, which were thus able to absorb and/or enhance the degradation of CA and FA. The adsorption capacity of SHA for the three allelochemicals was small and decreased in the order FA > CA > SA, thus suggesting that adsorption could be a relevant mechanism, but not the only one, involved in the "antiallelopathic" action.

  8. Structural characteristics of marine sedimentary humic acids by CP/MAS sup(13)C NMR spectroscopy

    Digital Repository Service at National Institute of Oceanography (India)

    Sardessai, S.; Wahidullah, S.

    acides humiques de la mer d’Arabie ; les acides humiques des stdiments estuariens et &tiers de la baie du Bengale sont dominks par les hyd.rates de carbone et les structures aro- matiques, ainsi que, dans une moindre mesure, par les structures... ont CtC Ctudiks dans diffkrents environnements de d6pp8ts par RMN du 13C (&at solide) et les rksultats ont Ctt cornparks avec les analyses chimiques traditionnelles en milieu liquide. Les donnkes obte- nues sont en accord avec la littkrature...

  9. Effects of extraction period on yield of rice straw compost humic acids

    African Journals Online (AJOL)

    PALANIVELL PERUMAL

    2012-03-08

    Mar 8, 2012 ... the dry combustion method (Cheftetz et al., 1996). The carboxylic, phenolic .... produces and donate more hydronium and hydrogen ions which could function as Brønsted-Lowry acid, and this might have replaced some of the remaining cations at HA exchange sites that were not replaced by hydrogen ions.

  10. Effects of humic substances on the migration of radionuclides: Complexation of actinides with humic substances

    International Nuclear Information System (INIS)

    Kim, J.I.; Rhee, D.S.; Wimmer, H.; Buckau, G.; Klenze, R.; Decambox, P.; Moulin, C.; Moulin, V.; Tits, J.; Marquardt, C.; Herrmann, G.; Trautmann, N.; Dierckx, A.; Vancluysen, J.; Maes, A.

    1992-09-01

    The aim of the present research programme is to study the complexation behaviour of actinide ions with humic substances in natural aquifer systems and hence to quantify the effect of humic substances on the actinide migration. Aquatic humic substances commonly found in all groundwaters in different concentrations have a strong tendency towards complexation with actinide ions. This is one of the major geochemical reactions but hitherto least quantified. Therefore, the effect of humic substances on the actinide migration is poorly understood. In the present research programme the complexation of actinide ions with humic substances will be described thermodynamically. This description will be based on a model being as simple as possible to allow an easy introduction of the resulting constants into geochemical modelling of the actinide migration. (orig.)

  11. Effects of humic substances on the migration of radionuclides: complexation of actinides with humic substances

    International Nuclear Information System (INIS)

    Kim, J.I.; Buckau, G.

    1993-01-01

    The aim of the present research programme is to study the complexation behaviour of actinide ions with humic substances in natural aquifer systems and hence to quantify the effect of humic substances on the actinide migration. Aquatic humic substances commonly found in all groundwaters in different concentrations have a strong tendency towards complexation with actinide ions. This is one of the major geochemical reactions but hitherto least quantified. Therefore, the effect of humic substances on the actinide migration is poorly understood. In the present research programme the complexation of actinide ions with humic substances will be described thermodynamically. This description will be based on a model being as simple as possible to allow an easy introduction of the resulting constants into geochemical modelling of the actinide migration. 13 refs

  12. Structure and catalytic activities of ferrous centers confined on the interface between carbon nanotubes and humic acid

    Science.gov (United States)

    Wang, Bing; Zhou, Xiaoyan; Wang, Dongqi; Yin, Jun-Jie; Chen, Hanqing; Gao, Xingfa; Zhang, Jing; Ibrahim, Kurash; Chai, Zhifang; Feng, Weiyue; Zhao, Yuliang

    2015-01-01

    Preparation of heterogeneous catalysts with active ferrous centers is of great significance for industrial and environmental catalytic processes. Nanostructured carbon materials (NCM), which possess free-flowing π electrons, can coordinate with transition metals, provide a confinement environment for catalysis, and act as potential supports or ligands to construct analogous complexes. However, designing such catalysts using NCM is still seldom studied to date. Herein, we synthesized a sandwich structured ternary complex via the coordination of Fe-loaded humic acid (HA) with C&z.dbd;C bonds in the aromatic rings of carbon nanotubes (CNTs), in which the O/N-Fe-C interface configuration provides the confinement environment for the ferrous sites. The experimental and theoretical results revealed octahedrally/tetrahedrally coordinated geometry at Fe centers, and the strong hybridization between CNT C π* and Fe 3d orbitals induces discretization of the atomic charges on aromatic rings of CNTs, which facilitates O2 adsorption and electron transfer from carbon to O2, which enhances O2 activation. The O2 activation by the novel HA/Fe-CNT complex can be applied in the oxidative degradation of phenol red (PR) and bisphenol A (BPA) in aqueous media.Preparation of heterogeneous catalysts with active ferrous centers is of great significance for industrial and environmental catalytic processes. Nanostructured carbon materials (NCM), which possess free-flowing π electrons, can coordinate with transition metals, provide a confinement environment for catalysis, and act as potential supports or ligands to construct analogous complexes. However, designing such catalysts using NCM is still seldom studied to date. Herein, we synthesized a sandwich structured ternary complex via the coordination of Fe-loaded humic acid (HA) with C&z.dbd;C bonds in the aromatic rings of carbon nanotubes (CNTs), in which the O/N-Fe-C interface configuration provides the confinement environment for the

  13. Partitioning of uranyl between ferrihydrite and humic substances at acidic and circum-neutral pH

    Science.gov (United States)

    Dublet, Gabrielle; Lezama Pacheco, Juan; Bargar, John R.; Fendorf, Scott; Kumar, Naresh; Lowry, Gregory V.; Brown, Gordon E.

    2017-10-01

    As part of a larger study of the reactivity and mobility of uranyl (U(VI)O22+) cations in subsurface environments containing natural organic matter (NOM) and hydrous ferric oxides, we have examined the effect of reference humic and fulvic substances on the sorption of uranyl on 2-line ferrihydrite (Fh), a common, naturally occurring nano-Fe(III)-hydroxide. Uranyl was reacted with Fh at pH 4.6 and 7.0 in the presence and absence of Elliott Soil Humic Acid (ESHA) (0-835 ppm) or Suwanee River Fulvic Acid (SRFA) (0-955 ppm). No evidence was found for reduction of uranyl by either form of NOM after 24 h of exposure. The following three size fractions were considered in this study: (1) ≥0.2 μm (Fh-NOM aggregates), (2) 0.02-0.2 μm (dispersed Fh nanoparticles and NOM macro-molecules), and (3) <0.02 μm (dissolved). The extent to which U(VI) is sorbed in aggregates or dispersed as colloids was assessed by comparing U, Fe, and NOM concentrations in these three size fractions. Partitioning of uranyl between Fh and NOM was determined in size fraction (1) using X-ray absorption spectroscopy (XAS). Uranyl sorption on Fh-NOM aggregates was affected by the presence of NOM in different ways depending on pH and type of NOM (ESHA vs. SRFA). The presence of ESHA in the uranyl-Fh-NOM ternary system at pH 4.6 enhanced uranyl uptake more than the presence of SRFA. In contrast, neither form of NOM affected uranyl sorption at pH 7.0 over most of the NOM concentration range examined (0-500 ppm); at the highest NOM concentrations (500-955 ppm) uranyl uptake in the aggregates was slightly inhibited at pH 7.0, which is interpreted as being due to the dispersion of Fh aggregates. XAS at the U LIII-edge was used to characterize molecular-level changes in uranyl complexation as a result of sorption to the Fh-NOM aggregates. In the absence of NOM, uranyl formed dominantly inner-sphere, mononuclear, bidentate sorption complexes on Fh. However, when NOM concentration was increased at pH 4.6, the

  14. Biogeochemical processes of incorporation and transformation of 14C labelled fulvic acid, humic acid and simple organic molecules at the sediment-water interface (submarine canyon of the NW Mediterranean)

    International Nuclear Information System (INIS)

    Buscail, R.; Gadel, F.

    1987-01-01

    The input of organic compounds at the marine water-sediment interface was simulated by the injection of 14 C labelled raygrass fulvic and humic acids and glutamic acid in the overlying water of three identically preserved interfaces. After incubations of 6 days under in situ conditions (13 0 C, oxidizing conditions), separation of the resulting products are carried out by successive chemical extractions. They correspond to the relative importance of biological (respiration, assimilation) and geochemical (condensation in geopolymers and adsorption) processes. Two experiments have showed predominance of biological processes (with 14 C fulvic and glutamic acids), while in the case of 14 C humic acid, incorporation in sediment and geochemical processes are more important. (Auth.)

  15. Humic acid facilitates the transport of ARS-labeled hydroxyapatite nanoparticles in iron oxyhydroxide-coated sand

    Science.gov (United States)

    Wang, Dengjun; Bradford, Scott A.; Harvey, Ronald W.; Gao, Bin; Cang, Long; Zhou, Dongmei

    2012-01-01

    Hydroxyapatite nanoparticles (nHAP) have been widely used to remediate soil and wastewater contaminated with metals and radionuclides. However, our understanding of nHAP transport and fate is limited in natural environments that exhibit significant variability in solid and solution chemistry. The transport and retention kinetics of Alizarin red S (ARS)-labeled nHAP were investigated in water-saturated packed columns that encompassed a range of humic acid concentrations (HA, 0–10 mg L–1), fractional surface coverage of iron oxyhydroxide coatings on sand grains (λ, 0–0.75), and pH (6.0–10.5). HA was found to have a marked effect on the electrokinetic properties of ARS-nHAP, and on the transport and retention of ARS-nHAP in granular media. The transport of ARS-nHAP was found to increase with increasing HA concentration because of enhanced colloidal stability and the reduced aggregate size. When HA = 10 mg L–1, greater ARS-nHAP attachment occurred with increasing λ because of increased electrostatic attraction between negatively charged nanoparticles and positively charged iron oxyhydroxides, although alkaline conditions (pH 8.0 and 10.5) reversed the surface charge of the iron oxyhydroxides and therefore decreased deposition. The retention profiles of ARS-nHAP exhibited a hyperexponential shape for all test conditions, suggesting some unfavorable attachment conditions. Retarded breakthrough curves occurred in sands with iron oxyhydroxide coatings because of time-dependent occupation of favorable deposition sites. Consideration of the above effects is necessary to improve remediation efficiency of nHAP for metals and actinides in soils and subsurface environments.

  16. Humic acid effect on catalase activity and the generation of reactive oxygen species in corn (Zea mays).

    Science.gov (United States)

    Cordeiro, Flávio Couto; Santa-Catarina, Claudete; Silveira, Vanildo; de Souza, Sonia Regina

    2011-01-01

    Humic acids (HAs) have positive effects on plant physiology, but the molecular mechanisms underlying these events are only partially understood. The induction of root growth and emission of lateral roots (LRs) promoted by exogenous auxin is a natural phenomenon. Exogenous auxins are also associated with HA. Gas nitric oxide (NO) is a secondary messenger produced endogenously in plants. It is associated with metabolic events dependent on auxin. With the application of auxin, NO production is significantly increased, resulting in positive effects on plant physiology. Thus it is possible to evaluate the beneficial effects of the application of HA as an effect of auxin. To investigate the effects of HA the parameters of root growth, Zea mays was studied by evaluating the application of 3 mM C L⁻¹ of HA extracted from Oxisol and 100 µM SNP (sodium nitroprusside) and the NO donor, subject to two N-NO₃⁻, high dose (5.0 mM N-NO₃⁻) and low dose (5.0 mM N-NO₃⁻). Treatments with HA and NO were positively increased, regardless of the N-NO₃⁻ taken, as assessed by fresh weight and dry root, issue of LRs. The effects were more pronounced in the treatment with a lower dose of N-NO₃⁻. Detection of reactive oxygen species (ROS) in vivo and catalase activity were evaluated; these tests were associated with root growth. Under application of the bioactive substances tested, detection of ROS and catalase activity increased, especially in treatments with lower doses of N-NO₃⁻. The results of this experiment indicate that the effects of HA are dependent on ROS generation, which act as a messenger that induces root growth and the emission of LRs.

  17. Impact of humic acid and chemical fertilizer application on growth and grain yield of rainfed wheat (triticum aestivum l.)

    International Nuclear Information System (INIS)

    Khan, R.U.; Khan, M.S.

    2010-01-01

    The high cost of inorganic fertilizer, use of natural fertilizer resources for increasing crop production on sustainable basis has become imperative. Two field experiments were conducted to study the potential of humic acid (HA) as a low-cost natural fertilizer and to determine its effect on the yield of rainfed wheat crop (Triticum aestivum L. cv. Naseer) at the research farm of Arid Zone Research Institute, Dera Ismail Khan during two successive winter seasons, 2007-08 and 2008-09. The treatments consisted of HA alone (3 kg ha/sup -1/ or 1.5 kg ha/sup -1/) and in combination with full (60:40 kg ha/sup -1/) and half (30:20 kg ha/sup -1/) the recommended rates of NP fertilizers. Results showed that in the first growing season (2007-08), the combination of 3 kg ha/sup -1/ HA with half (30:20 kg ha-1) rate of NP produced the highest grain yield (1314 kg ha/sup -1/) and increased the yield by 46.9% over the control. In the second growing season (2008-09), application of 3 kg ha/sup -1/ HA alone produced significantly (P<0.05) higher grain yield (2999.9 kg ha/sup -1/) and increased the yield by 24% over the control and saved 100% cost of the chemical fertilizer. Results suggested that HA applied alone at 3 kg ha/sup -1/ or in combination with half (30:20 kg ha/sup -1/) rate of NP fertilizers appeared to be the most economical rate to obtain the maximum yield of wheat under the rainfed conditions of Dera Ismail Khan. HA has great potential as a low cost natural fertilizer to improve soil fertility on sustainable basis. (author)

  18. Accelerated removal of Sudan dye by Shewanella oneidensis MR-1 in the presence of quinones and humic acids.

    Science.gov (United States)

    Liu, Guangfei; Zhou, Jiti; Ji, Qiuyan; Wang, Jing; Jin, Ruofei; Lv, Hong

    2013-09-01

    Although there have been many studies on bacterial removal of soluble azo dyes, much less information is available for biological treatment of water-insoluble azo dyes. The few bacterial species capable of removing Sudan dye generally require a long time to remove low concentrations of insoluble dye particles. The present work examined the efficient removal of Sudan I by Shewanella oneidensis MR-1 in the presence of redox mediator. It was found that the microbially reduced anthraquinone-2,6-disulfonate (AQDS) could abiotically reduce Sudan I, indicating the feasibility of microbially-mediated reduction. The addition of 100 μM AQDS and other different quinone compounds led to 4.3-54.7 % increase in removal efficiencies in 22 h. However, adding 5-hydroxy-1,4-naphthoquinone into the system inhibited Sudan I removal. The presence of 10, 50 and 100 μM AQDS stimulated the removal efficiency in 10 h from 26.4 to 42.8, 54.9 and 64.0 %, respectively. The presence of 300 μM AQDS resulted in an eightfold increase in initial removal rate from 0.19 to 1.52 mg h⁻¹ g⁻¹ cell biomass. A linear relationship was observed between the initial removal rates and AQDS concentrations (0-100 μM). Comparison of Michaelis-Menten kinetic constants revealed the advantage of AQDS-mediated removal over direct reduction. Different species of humic acid could also stimulate the removal of Sudan I. Scanning electronic microscopy analysis confirmed the accelerated removal performance in the presence of AQDS. These results provide a potential method for the efficient removal of insoluble Sudan dye.

  19. Study on the Fouling Behavior of Polyethylene and Silica Nanoparticles Mixed Matrix Membranes in Filtration of Humic Acid Solution

    Directory of Open Access Journals (Sweden)

    Ali Akbari

    2016-09-01

    Full Text Available Because most contaminants in water create strong interactions with hydrophobic surfaces, there are usually problems such as flux decline and pore blocking in polyethylene (PE membranes due to irreversible adsorption of foulants on their intrinsic hydrophobic surface. Therefore, in this work, attempts were made to improve the properties of PE membranes in terms of water flux and membrane fouling resistance by dispersion of silica nanoparticles (NPs. First, NPs were synthesized by sol-gel method at two concentrations of ammonia (0.5 and 1 mol/L. The synthesized NPs with smaller size were used to fabricate the mixed matrix PE membranes containing 0, 0.5, 1 and 2 wt% NPs. FE-SEM and EDX analyses were employed to evaluate the morphology and structure of the fabricated membranes and confirmed the presence of NPs in the membranes matrix. The results of pure water flux test revealed that the membrane containing 1 wt% NPs displayed the maximum flux of 30 L/m2.h. Furthermore, the performance and fouling behaviors of membranes during filtration of humic acid solution, one of the most important contaminants of water resources, were studied using a classical fouling model. Fouling mechanism analysis showed that for neat and NPs-embedded membranes containing 0.5 and 2 wt% NPs, the best fit of the data was obtained by cake layer formation as well as the intermediate blocking mechanisms. However, the best fit of the experimental data of NPs-embedded membrane containing 1 wt% occurred with only cake layer formation mechanism. The investigation on membrane fouling resistance showed that 1 wt% NPs-embedded membrane displayed 58% maximum flux recovery and 52% reversibility to total fouling ratio, respectively.

  20. Impact of de-ashing humic Acid and humin on organic matter structural properties and sorption mechanisms of phenanthrene.

    Science.gov (United States)

    Yang, Yu; Shu, Liang; Wang, Xilong; Xing, Baoshan; Tao, Shu

    2011-05-01

    Organic matter-mineral interactions greatly affect the fate of hydrophobic organic compounds (HOCs) in the environment. In the present study, the impact of organic matter-mineral interaction on sorption of phenanthrene (PHE) by the original and de-ashed humic acids (HAs) and humin (HM) was examined. After de-ashing treatment, the overall polarity of organic matter in HAs and HM consistently decreased. Differently, the surface polarity of HAs increased but that of HM decreased. No correlation between K(oc) values of PHE by all tested sorbents and their bulk polarity was observed due to inaccessibility of a portion of interior sorption domains. The inaccessibility of interior sorption domains in HAs and HM was partly due to the crystalline structure in organic matter as indicated by differential scanning calorimetric (DSC) and ¹³C NMR data and the interference from minerals. A good correlation between surface polarity of the original and de-ashed HAs and HMs and their K(oc) values for PHE indicated its importance in HOC sorption. Dissimilar changes in surface polarity of HAs and HM after de-ashing treatment can be ascribed to the distinct interactions between organic matter and minerals. The solid-state ¹³C NMR, XPS, and elemental composition data of all tested sorbents revealed that a larger fraction of O atoms in HAs were involved in organic matter-mineral interaction as compared to HM. Results of this work highlight the importance of soil organic matter (SOM)-mineral interactions, surface polarity, and microscaled domain arrangement of SOM in HOC sorption.

  1. Effect of humic acid on pyrene removal from water by polycation-clay mineral composites and activated carbon.

    Science.gov (United States)

    Radian, Adi; Mishael, Yael

    2012-06-05

    Pyrene removal by polycation-montmorillonite (MMT) composites and granulated activated carbon (GAC) in the presence of humic acid (HA) was examined. Pyrene, HA, and sorbent interactions were characterized by FTIR, fluorescence and zeta measurements, adsorption, and column filtration experiments. Pyrene binding coefficients to the macromolecules were in the order of PVPcoS (poly-4-vinylpiridine-co-styrene) > HA > PDADMAC (poly diallyl-dimethyl-ammonium-chloride), correlating to pyrene-macromolecules compatibility. Electrostatic interactions explained the high adsorption of HA to both composites (∼100%), whereas HA adsorption by GAC was low. Pyrene removal by the composites, unlike GAC, was enhanced in the presence of HA; removal by PDADMAC-MMT increased from ∼50 (k(d) = 2.2 × 10(3) kg/L) to ∼70% (k(d) = 2.4 × 10(3) kg/L) in the presence of HA. This improvement was attributed to the adsorption of pyrene-HA complexes. PVPcoS-MMT was most efficient in removing pyrene (k(d) = 1.1 × 10(4) kg/L, >95% removal) which was explained in terms of specific π donor-π acceptor interactions. Pyrene uptake by column filters of GAC reached ∼50% and decreased to ∼30% in the presence of HA. Pyrene removal by the PVPcoS-MMT filter was significantly higher (100-85% removal), exhibiting only a small decrease in the presence of HA. The utilization of HA as an enhancing agent in pollutant removal is novel and of major importance in water treatment.

  2. Degradation and structure change of humic acids corresponding to water decline in Zoige peatland, Qinghai-Tibet Plateau

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Xuejun, E-mail: guoxj21@yahoo.com.cn; Du, Wei; Wang, Xuan; Yang, Zhifeng, E-mail: zfyang@bnu.edu.cn

    2013-02-15

    As the largest plateau-type wetland in the world and the largest peat storage in China, Zoige wetland faces severe water decline, and consequently accelerated peat degradation and carbon emission. Here, a variety of characterization approaches, including elemental analysis, UV–vis spectra, FT-IR spectra, and solid state {sup 13}C NMR spectra were used to investigate the degradation and the structural shift of humic acids (HAs) in correspondence with serious water loss in Zoige peatland. Water loss derived from both natural slope and artificial drainage caused a substantial degradation of organic matter and HAs. Compared with the blocks immersed by free surface water, HAs extracted from the drier blocks had more pronounced signals of carboxyl and carbonyl groups, but carried lower content of methoxyl, carbohydrate, alcohol and ether groups. The total aliphatic carbon in HAs from natural-slope drier site decreased almost one half, but in the artificial-drained site, only slightly decreased. Correspondingly, the HA aromaticity substantially increased in the site undergoing the longer time of aerobic oxidation, whereas varied little in the site impacted by extensive water leaching. - Highlights: ► HAs were decomposed significantly due to water loss in Zoige peatland. ► Water loss induced a significant shift in FT-IR and {sup 13}C NMR spectra of HAs. ► The ratio of aliphatic to O-aliphatic carbon (A/O-A ratio) dramatically increased. ► The aromaticity of HAs increased with water loss in the higher-altitude site.

  3. Effects of humic acid and heavy metals on the sorption of polar and apolar organic pollutants onto biochars.

    Science.gov (United States)

    Wang, Fei; Sun, Hongwen; Ren, Xinhao; Liu, Yarui; Zhu, Hongkai; Zhang, Peng; Ren, Chao

    2017-12-01

    The effects of humic acid (HA) and heavy metals (Cu 2+ and Ag + ) on the sorption of polar and apolar organic pollutants onto biochars that were produced at temperatures of 200 °C (BC200) and 700 °C (BC700) were studied. Due to the plentiful polar functional groups on BC200, cationic propranolol exhibited higher levels of sorption than naphthalene on BC200 while naphthalene and propranolol showed similar sorption capacities on BC700. HA changed the characteristics of biochars and generally inhibited the sorption of target organic pollutants on biochars; however, enhancement occurred in some cases depending on the pollutants involved and their concentrations, biochars used and the addition sequences and concentrations of HA. On BC200, HA modifications mainly influenced sorption by decreasing its polarity and increasing its aromaticity, while on BC700, the surface area and pore volume greatly decreased due to the pore-blocking effects of HA. Residue dissolved HA in solution may also contribute to sorption inhibition. Complexation between polar functional groups on BC200 and heavy metals slightly enhanced the sorption of neutral naphthalene and significantly enhanced that of anionic 4-nitro-1-naphtol, while limited the sorption of cationic propranolol. Heavy metals together with their associated water molecules decreased the sorption of target chemicals on BC700 via pore-filling or pore-mouth-covering. Inhibition of heavy metals for 4-nitro-1-naphthol was found to be the weakest due to the bridge effects of heavy metals between 4-nitro-1-naphtol and BC700. The higher polarizability of Ag + led to the increase of its sorption on biochars in the presence of organic aromatic pollutants. The results of the present study shed light on the sorption mechanisms of bi-solute systems and enable us to select suitable biochar sorbents when chemicals co-exist. Copyright © 2017. Published by Elsevier Ltd.

  4. Contribution of bacterial cell nitrogen to soil humic fractions

    International Nuclear Information System (INIS)

    Knowles, R.; Barro, L.

    1981-01-01

    Living cells of Serratia marcescens, uniformly labelled with 15 N, were added to samples of maple (Acer saccharum) and black spruce (Picea mariana) forest soils. After different periods of incubation from zero time to 100 days, the soils were subjected to alkali-acid and phenol extraction to provide humic acid, fulvic acid, humin and 'humoprotein' fractions. Significant amounts of the cell nitrogen were recovered in the humic and fulvic acids immediately after addition. After incubation, less cell nitrogen appeared in the humic acid and more in the fulvic acid. The amount of cell nitrogen recovered in the humin fraction increased with incubation. Roughly 5 to 10 per cent of the added cell nitrogen was found as amino acid nitrogen from humoprotein in a phenol extract of the humic acid. The data are consistent with the occurrence of co-precipitation of biologically labile biomass nitrogen compounds with humic polymers during the alkaline extraction procedure involved in the humic-fulvic fractionation. (orig.)

  5. Fractal nature of humic materials

    Science.gov (United States)

    Rice, J. A.; Lin, J. S.

    Fractals are geometric representatives of strongly disordered systems whose structure is described by nonintegral dimensions. A fundamental tenet of fractal geometry is that disorder persists at any characterization scale-length used to describe the system. The nonintegral nature of these fractal dimensions is the result of the realization that a disordered system must possess more structural detail than an ordered system with classical dimensions of 1, 2, or 3 in order to accommodate this 'disorder within disorder.' Thus from a fractal perspective, disorder is seen as an inherent characteristic of the system rather than as a perturbative phenomena forced upon it. Humic materials are organic substances that are formed by the profound alteration of organic matter in a natural environment. They can be operationally divided into 3 fractions; humic acid (soluble in base), fulvic acid (soluble in acid or base), and humin (insoluble in acid or base). Each of these fractions has been shown to be an extremely heterogeneous mixture. These mixtures have proven so intractable that they may represent the ultimate in molecular disorder. In fact, based on the characteristics that humic materials must possess in order to perform their functions in natural systems, it has been proposed that the fundamental chemical characteristic of a humic material is not a discrete chemical structure but a pronounced lack of order on a molecular level. If the fundamental chemical characteristic of a humic material is a strongly disordered nature, as has been proposed, then humic materials should be amenable to characterization by fractal geometry. The purpose of this paper is to test this hypothesis.

  6. Heavy metal transport by humic acid in underground water - investigations on europium; Untersuchungen zum huminstoffgetragenen Schwermetall-Transport im unterirdischen Wasser - durchgefuehrt am Beispiel des Europiums

    Energy Technology Data Exchange (ETDEWEB)

    Klotz, D. (ed.)

    2001-12-01

    Colloids, i.e. particulates of 1 nm to 1 {mu}m suspended in water, are found in all types of groundwater, either as organic colloids, inorganic colloids, or mixtures of both. Their concentration, chemical composition, structure and particle size varies with the geochemistry of the sediment-water system. Inorganic colloids are Al-Fe-Mn mixed oxides, clays and other complex minerals. Organic colloids consist of humic and fulvic acids which are the main constituent of the dissolved organic carbon. Humic acids are capable of forming metal humate complexes with metal ions via proton-exchanging groups. Radionuclides, too, are transported with humic acid, especially trivalent and multivalent metal ions of the lanthanides and actinides as well as radio-iodine. [German] In allen Grundwaessern werden Kolloide, d.h. im Wasser suspendierte Teilchen mit Durchmessern im Bereich 1 nm bis 1 {mu}m gefunden. Die Zusammensetzung der Kolloide kann sowohl organischer als auch anorganischer Natur sein, wobei in vielen Grundwaessern eine Mischung beider Kolloidarten auftritt. Die Konzentration, die chemische Zusammensetzung, die Struktur und die Teilchengroesse natuerlicher Kolloide variieren stark, sie sind abhaengig von der Geochemie des Sediment-Wasser-Systems. Anorganische Kolloide sind Al-Fe-Mn-Mischoxide, Tone and andere komplexe Mineralien. Organische Kolloide bestehen aus Humin- und Fulvinsaeuren; diese Huminstoffe bilden den Hauptbestandteil des geloesten organischen Kohlenstoffs. Eine wichtige Eigenschaft der Huminstoffe ist ihre Faehigkeit, mit Metallionen ueber protonenaustauschende Gruppen Komplexe - sog. Metall-Humate - zu bilden. Auch Radionuklide, insbesondere drei- und mehrwertige Metallionen der Lanthaniden und Actiniden sowie Radio-Iod werden an Huminstoffe gebunden. Damit koennen Radionuklide nicht nur in Form einfacher Spezies, sondern auch huminstoffgebunden transportiert werden. (orig.)

  7. Sorption of selected organic compounds from water to a peat soil and its humic-acid and humin fractions: Potential sources of the sorption nonlinearity

    Science.gov (United States)

    Chiou, C.T.; Kile, D.E.; Rutherford, D.W.; Sheng, G.; Boyd, S.A.

    2000-01-01

    The sorption isotherms of ethylene dibromide (EDB), diuron (DUN), and 3,5-dichlorophenol (DCP) from water on the humic acid and humin fractions of a peat soil and on the humic-acid of a muck soil have been measured. The data were compared with those of the solutes with the whole peat from which the humic-acid (HA) and humin (HM) fractions were derived and on which the sorption of the solutes exhibited varying extents of nonlinear capacities at low relative concentrations (C(e)/S(w)). The HA fraction as prepared by the density-fractionated method is relatively pure and presumably free of high- surface-area carbonaceous material (HSACM) that is considered to be responsible for the observed nonlinear sorption for nonpolar solutes (e.g., EDB) on the peat; conversely, the base-insoluble HM fraction as prepared is presumed to be enriched with HSACM, as manifested by the greatly higher BET- (N2) surface area than that of the whole peat. The sorption of EDB on HA exhibits no visible nonlinear effect, whereas the sorption on HM shows an enhanced nonlinearity over that on the whole peat. The sorption of polar DUN and DCP on HA and HM display nonlinear effects comparable with those on the whole peat; the effects are much more significant than those with nonpolar EDB. These results conform to the hypothesis that adsorption onto a small amount of strongly adsorbing HSACM is largely responsible for the nonlinear sorption of nonpolar solutes on soils and that additional specific interactions with the active groups of soil organic matter are responsible for the generally higher nonlinear sorption of the polar solutes.

  8. Effect of PVP on the characteristic of modified membranes made from waste PET bottles for humic acid removal [version 2; referees: 2 approved

    Directory of Open Access Journals (Sweden)

    Nasrul Arahman

    2017-06-01

    Full Text Available Background: The aim of the present study was to evaluate the possibility of using recycled polymer (waste polyethylene terephthalate [PET] bottles as a membrane material. Furthermore, the effect of the addition of a pore-forming agent and preparation conditions was also observed. Methods: Porous polymeric membranes were prepared via thermally induced phase separation by dissolving recycled PET in phenol. PET polymer was obtained from waste plastic bottles as a new source of polymeric material. For original PET membrane, the casting solution was prepared by dissolving of 20wt% PET in phenol solution. For PET modified membrane, a 5 wt% of polyvinylpyrrolidone (PVP was added into polymer solution. The solution was cast onto a glass plate at room temperature followed by evaporation before the solidification process. The membranes formed were characterized in terms of morphology, chemical group, and filtration performance. A humic acid solution was used to identify the permeability and the solute rejection of the membranes. Results: The results showed that the recycled PET from waste plastic bottles was applicable to use as a membrane material for a water treatment process. The maximum flux of 97.0 l/m2.hr was obtained from filtration test using PET membrane. The highest rejection of humic acid in a water sample, which reached up to 75.92%, was obtained using the PET/PVP membrane. Conclusions: The recycled PET from waste bottles was successfully used to prepare porous membrane. The membrane was modified by the addition of PVP as a membrane modifying agent. SEM analysis confirmed that the original PET membrane has a rough and large pore structure. The addition of PVP improved the pore density with a narrow pore structure. The PET/PVP membrane conditioned with evaporation was the best in humic acid rejection.

  9. May humic acids or mineral fertilisation mitigate arsenic mobility and availability to carrot plants (Daucus carota L.) in a volcanic soil polluted by As from irrigation water?

    Science.gov (United States)

    Caporale, Antonio G; Adamo, Paola; Azam, Shah M G G; Rao, Maria A; Pigna, Massimo

    2018-02-01

    Carrot (Daucus carota L.) is a widely consumed root vegetable, whose growth and safety might be threatened by growing-medium arsenic (As) contamination. By this work, we evaluated the effects of humic acids from Leonardite and NPK mineral fertilisation on As mobility and availability to carrot plants grown for 60 days in a volcanic soil irrigated with As-contaminated water - representing the most common scenario occurring in As-affected Italian areas. As expected, the irrigation with As-contaminated water caused a serious toxic effect on plant growth and photosynthetic rate; the highest rate of As also inhibited soil enzymatic activity. In contrast, the organic and mineral fertilisation alleviated, at least partially, the toxicity of As, essentially by stimulating plant growth and promoting nutrient uptake. The mobility of As in the volcanic soil and thus its phytoavailability were differently affected by the organic and mineral fertilisers; the application of humic acids mitigated the availability of the contaminant, likely by its partial immobilisation on humic acid sorption sites - thus raising up the intrinsic anionic sorption capacity of the volcanic soil; the mineral fertilisation enhanced the mobility of As in soil, probably due to competition of P for the anionic sorption sites of the soil variable-charge minerals, very affine to available P. These findings hence suggest that a proper soil management of As-polluted volcanic soils and amendment by stable organic matter might mitigate the environmental risk of these soils, thus minimising the availability of As to biota. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Synthesis, characterization and visible light photocatalytic activity of Cr 3+ , Ce 3+ and N co-doped TiO 2 for the degradation of humic acid

    KAUST Repository

    Rashid, S. G.

    2015-01-01

    The synthesis, characterization and photocatalytic activity of Cr3+ and Ce3+ co-doped TiON (N-doped TiO2) for the degradation of humic acid with exposure to visible light is reported. The synthesized bimetal (Cr3+ + Ce3+) modified TiON (Cr-Ce/TiON), with an evaluated bandgap of 2.1 eV, exhibited an enhanced spectral response in the visible region as compared to pure and Ce3+ doped TiON (Ce/TiON). The XRD analysis revealed the insertion of Cr3+ and Ce3+ in the crystal lattice along with Ti4+ and N that resulted in the formation of a strained TiON anatase structure with an average crystallite size of ∼10 nm. Raman analysis also supported the formation of stressed rigid structures after bimetal doping. HRTEM confirmed the homogeneous distribution of both the doped metallic components in the crystal lattice of TiON without the formation of surface oxides of either Cr3+ or Ce3+. Electron energy loss spectroscopy (EELS) analysis revealed no change in the oxidation of either Cr or Ce during the synthesis. The synthesized Cr-Ce/TiON catalyst exhibited appreciable photocatalytic activity for the degradation of humic acid on exposure to visible light. Additionally, a noticeable mineralization of carbon rich humic acid was also witnessed. The photocatalytic activity of the synthesized catalyst was compared with pristine and Ce3+ doped TiON. © The Royal Society of Chemistry 2015.

  11. Effects of a dietary complex of humic and fulvic acids (FeedMAX 15) on the health and production of feedlot cattle destined for the Australian domestic market.

    Science.gov (United States)

    Cusack, P M V

    2008-01-01

    To examine the effects of a dietary humic and fulvic acid complex, FeedMAX 15, on the health, growth rate, feed conversion ratio, and carcase characteristics of feedlot cattle. Cattle, in eight pens of 125 animals each, were fed either a diet containing a humic and fulvic acid complex (FeedMAX 15, FeedMAX Industries, Toowoomba, Queensland) or the same diet without the additive. Control or FeedMAX 15 diets were allocated to each pen at random. Individual cattle were allocated alternately to control or treatment pens based on order of presentation. Comparisons of disease incidence, mortality, feed intake, growth rate, feed conversion ratio, fat depth, dressing percentage, meat colour, fat colour and marbling were made at the conclusion of the feeding period. No differences were found between cattle fed FeedMAX 15 and cattle not fed the additive in entry body weight (P = 0.99), exit body weight (P = 0.91), dressing percentage (P = 0.66), P8 fat depth (P = 0.57), meat colour (P = 0.67), marbling (P = 0.70), all diseases (P = 0.64), bovine respiratory disease (P = 0.91), or mortalities (P = 1.0). Cattle fed FeedMAX 15 reached the market specifications for body weight and fat depth in fewer mean days (P = 0.0001), had a greater average daily gain (P = 0.05), a lower feed conversion ratio (P = 0.05) and whiter fat (P < 0.0001). Feeding the humic and fulvic acid complex, FeedMAX 15, at 0.055 g per kg body weight per day, can increase growth rate and feed conversion efficiency in feedlot cattle.

  12. Enzymatic treatment for controlling irreversible membrane fouling in cross-flow humic acid-fed ultrafiltration

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Chien-Hwa [Department of Civil and Environment Engineering, Nanya Institute of Technology, Taoyuan, Taiwan (China); Fang, Lung-Chen; Lateef, Shaik Khaja [Graduate Institute of Environmental Engineering, National Taiwan University, Taipei, Taiwan (China); Wu, Chung-Hsin, E-mail: chunghsinwu@yahoo.com.tw [Department of Chemical and Materials Engineering, National Kaohsiung University of Applied Sciences, 415 Chien Kung Road, Kaohsiung 807, Taiwan (China); Lin, Cheng-Fang [Graduate Institute of Environmental Engineering, National Taiwan University, Taipei, Taiwan (China)

    2010-05-15

    Exploring reasonable ways to remove foulant is of great importance in order to allow sustainable operation of ultrafiltration (UF) membranes in water/wastewater treatment technology. Compounds of organic and inorganic origin largely contribute to irreversible fouling. This study attempted to remove problem of UF membrane fouling by using four different enzymes including {alpha}-amylase, lipase, cellulase and protease. This investigation showed that none of the above mentioned enzymes was found to be effective for the removal of foulant when used alone. However, when these enzymes were used in combination with NaOH and citric acid, about 90% cleaning was achieved. The addition of non-ionic surfactant to the enzymatic solution appears to increase the efficiency of flux recovery by reducing the adhesion of foulant species to the membrane surface through the decrease of contact angle. Field emission gun scanning electron microscopy, Fourier transform infrared spectroscopy and atomic force microscopy (AFM) techniques were employed to qualitatively illustrate the foulant characteristics. The surface roughness through AFM was used to explain the potential mechanism for the enzymatic cleaning.

  13. Investigation of the complexation and the migration of actinides and non-radioactive substances with humic acids under geogenic conditions. Complexation of humic acids with actinides in the oxidation state IV Th, U, Np

    International Nuclear Information System (INIS)

    Sachs, S.; Schmeide, K.; Brendler, V.; Krepelova, A.; Mibus, J.; Geipel, G.; Heise, K.H.; Bernhard, G.

    2004-03-01

    Objective of this project was the study of basic interaction and migration processes of actinides in the environment in presence of humic acids (HA). To obtain more basic knowledge on these interaction processes synthetic HA with specific functional properties as well as 14 C-labeled HA were synthesized and applied in comparison to the natural HA Aldrich. One focus of the work was on the synthesis of HA with distinct redox functionalities. The obtained synthetic products that are characterized by significantly higher Fe(III) redox capacities than Aldrich HA were applied to study the redox properties of HA and the redox stability of U(VI) humate complexes. It was confirmed that phenolic OH groups play an important role for the redox properties of HA. However, the results indicate that there are also other processes than the single oxidation of phenolic OH groups and/or other functional groups contributing to the redox behavior of HA. A first direct-spectroscopic proof for the reduction of U(VI) by synthetic HA with distinct redox functionality was obtained. The complexation behavior of synthetic and natural HA with actinides (Th, Np, Pu) was studied. Structural parameters of Pu(III), Th(IV), Np(IV) and Np(V) humates were determined by X-ray absorption spectroscopy (XAS). The results show that carboxylate groups dominate the interaction between HA and actinide ions. These are predominant monodentately bound. The influence of phenolic OH groups on the Np(V) complexation by HA was studied with modified HA (blocked phenolic OH groups). The blocking of phenolic OH groups induces a decrease of the number of maximal available complexing sites of HA, whereas complex stability constant and Np(V) near-neighbor surrounding are not affected. The effects of HA on the sorption and migration behavior of actinides was studied in batch and column experiments. Th(IV) sorption onto quartz and Np(V) sorption onto granite and its mineral constituents are affected by the pH value and the

  14. Investigation of the complexation and the migration of actinides and non-radioactive substances with humic acids under geogenic conditions. Complexation of humic acids with actinides in the ocidation state IV Th, U, Np

    Energy Technology Data Exchange (ETDEWEB)

    Sachs, S.; Schmeide, K.; Brendler, V.; Krepelova, A.; Mibus, J.; Geipel, G.; Heise, K.H.; Bernhard, G.

    2004-03-01

    Objective of this project was the study of basic interaction and migration processes of actinides in the environment in presence of humic acids (HA). To obtain more basic knowledge on these interaction processes synthetic HA with specific functional properties as well as {sup 14}C-labeled HA were synthesized and applied in comparison to the natural HA Aldrich. One focus of the work was on the synthesis of HA with distinct redox functionalities. The obtained synthetic products that are characterized by significantly higher Fe(III) redox capacities than Aldrich HA were applied to study the redox properties of HA and the redox stability of U(VI) humate complexes. It was confirmed that phenolic OH groups play an important role for the redox properties of HA. However, the results indicate that there are also other processes than the single oxidation of phenolic OH groups and/or other functional groups contributing to the redox behavior of HA. A first direct-spectroscopic proof for the reduction of U(VI) by synthetic HA with distinct redox functionality was obtained. The complexation behavior of synthetic and natural HA with actinides (Th, Np, Pu) was studied. Structural parameters of Pu(III), Th(IV), Np(IV) and Np(V) humates were determined by X-ray absorption spectroscopy (XAS). The results show that carboxylate groups dominate the interaction between HA and actinide ions. These are predominant monodentately bound. The influence of phenolic OH groups on the Np(V) complexation by HA was studied with modified HA (blocked phenolic OH groups). The blocking of phenolic OH groups induces a decrease of the number of maximal available complexing sites of HA, whereas complex stability constant and Np(V) near-neighbor surrounding are not affected. The effects of HA on the sorption and migration behavior of actinides was studied in batch and column experiments. Th(IV) sorption onto quartz and Np(V) sorption onto granite and its mineral constituents are affected by the pH value

  15. Simultaneous removal of As, Cd, Cr, Cu, Ni and Zn from stormwater using high-efficiency industrial sorbents: Effect of pH, contact time and humic acid

    DEFF Research Database (Denmark)

    Genc-Fuhrman, Hülya; Mikkelsen, Peter Steen; Ledin, Anna

    2016-01-01

    The effect of contact time, solution pH, and the presence of humic acid (HA) on the combined removal of As, Cd, Cr, Cu, Ni and Zn is investigated in batch tests using alumina, granulated activated carbon (GAC), and bauxsol coated sand (BCS) as sorbents. It is found that the equilibrium time for Cd...... their removal. The presence of both 20 and 100 mg/L HA suppressed the heavy metal removal except for Cr, and the suppression was higher at the higher HA concentration. Geochemical simulations suggest that this is due to the formation of dissolved HA-metal complexes preventing effective metal sorption...

  16. Chromatography of humic substances on controlled pore glass

    International Nuclear Information System (INIS)

    Danneberg, O.H.

    1977-01-01

    To check the suitability of controlled pore glass (CPG) for the chromatography of humic substances, a soil extract from an Austrian chernozem and humic fractions prepared from the extract were chromatographed using a column filled with CPG of a pore diameter of 156A. The chromatograms obtained were reproducible, and showed the expected sequence of elution, grey humic acids (GHA) being eluted before brown humic acids (BHA) and fulvic acids (FA). Chromatograms of complex humic systems agreed well with the computed sums of the chromatograms of all its components. This means that all humic substances moved through the column independently of the presence or absence of others. From these findings, the suitability of CPG for chromatography of humic substances was concluded. A structural alteration of GHA during the preparation was detected. This was accompanied by a decrease in molecular weight and an increase in colour intensity. (author)

  17. Effect of Different Levels of Nitroxin and Humic Acid on Quantitative Properties and Essential Oil of Ajowan (Carum copticum (L. C. B. Clarke

    Directory of Open Access Journals (Sweden)

    K. Barghamadi

    2016-02-01

    agricultural products. Humic acid, as one of the appropriate fertilizer, is used in the agricultural organic system. Humic acid causes shoot growth increase due to the absorption of calcium, nitrogen, phosphorus, potassium, manganese, iron, zinc and copper. Bio-fertilizer application information on medicinal plants is very important. In the present study, nitroxin and humic acid effects on Carumcopticum extract were investigated. Materials and Methods: In order to evaluate the effect of different levels of humic acid, organic fertilizer and Nitroxin bio-fertilizer on quantitative and qualitative characteristics of Ajowan, a factorial experiment in a randomized complete block design with three replications was conducted in Zabol University. The seeds used in this study were obtained from a local variety that was planted superficially. Active ingredientof the seed was extracted by distillation with water for threehours. Essence percentage was determined by sodium sulfate. The Kejeldal method was used to determine the percentage of nitrogen. The crude method was used to determine the concentration of calcium, potassium, phosphorus and magnesium in dry ash. A factorial experiment in a randomized complete block design with three replications was conducted at the Research Farm. Treatments include the seed inoculation with Nitroxin bio-fertilizer in fourlevels including N1= zero (control, N2 = 0.5, N3 = 1 and N4 = 1.5 L/ha and organic fertilizer humic acid as irrigation water solublefour-leaf stage on fourlevels H1 = zero (control, H2 = 1, H3 = 2 and H4 = 3 kg per hectare. SAS statistical software was used to analyze the data and mean of three traits were compared by LSD test at the 5% level. Results and Discussion: None of the treatments affected plant height and Nitroxinhumic acid interactions were not significant. The results showed significant effects of humic acid on seed weight, number of umbels and lateral branches, essential oil percentage and yield. The highest percentage

  18. The transformation of triclosan by laccase: Effect of humic acid on the reaction kinetics, products and pathway.

    Science.gov (United States)

    Dou, Rong-Ni; Wang, Jing-Hao; Chen, Yuan-Cai; Hu, Yong-You

    2018-03-01

    This study systematically explored the effect of humic acid (HA) (as model of natural organic matter) on the kinetics, products and transformation pathway of triclosan (TCS) by laccase-catalyzed oxidation. It was found that TCS could be effectively transformed by laccase-catalysis, with the apparent second-order rate constant being 0.056 U -1 mL min -1 . HA inhibited the removal rate of TCS. HA-induced inhibition was negatively correlated with HA concentration in the range of 0-10 mg L -1 and pH-dependent from 3.5 to 9.5. FT-IR and 13 C NMR spectra showed a decrease of aromatic hydroxyl (phenolic) groups and an increase of aromatic ether groups, indicating the cross-linking of HA via C-O-C and C-N-C bonds during enzyme-catalyzed oxidation. Ten principle oxidative products, including two quinone-like products (2-chlorohydroquinone, 2-chloro-5-(2,4-dichlodichlorophenoxy)-(1,4)benzoquinone), one chlorinated phenol (2,4-dichlorophenol (2,4-DCP)), three dimers, two trimmers and two tetramers, were detected by gas chromatograghy/mass spectrometry (GC-MS) and high performance liquid chromatography/quadrupole time-of-flight/mass spectrometry (HPLC/Q-TOF/MS). The presence of HA induced significantly lesser generation of self-polymers and enhanced cross-coupling between HA and self-polymers via C-O-C, C-N-C and C-C coupling pathways. A plausible transformation pathway was proposed as follows: TCS was initially oxidized to form reactive phenoxyl radicals, which self-coupled to each other subsequently by C-C and C-O pathway, yielding self-polymers. In addition, the scission of ether bond was also observed. The presence of HA can promote scission of ether bond and further oxidation of phenoxyl radicals, forming hydroxylated or quinone-like TCS. This study shed light on the behavior of TCS in natural environment and engineered processes, as well provided a perspective for the water/wastewater treatment using enzyme-catalyzed oxidation techniques. Copyright © 2017 Elsevier Ltd

  19. Sorption of estrogens and pesticides from aqueous solution by a humic acid and raw and processed plant materials

    Science.gov (United States)

    Loffredo, Elisabetta; Taskin, Eren

    2016-04-01

    The huge number of organic contaminants released in water as a consequence of anthropogenic activities have detrimental effects to environmental systems and human health. Industrial products and byproducts, pharmaceuticals, pesticides, detergents and so on impose increasing costs for wastewater decontamination. Adsorption techniques can be successfully used for the treatment of wastewaters to remove contaminants of various nature. Humic acids (HA) have well-known adsorptive capacities towards hydrophilic and, especially, hydrophobic compounds. In the recent years, alternative low-cost adsorbents, especially originated from agricultural wastes and food industries residues, such as wood chips, almond and coconut shells, peanut and rice husks, are under investigation. Biochar is also considered a promising and relatively low-cost adsorbent, even if there are still knowledge gaps about the influence of feedstock type, pyrolysis conditions, physical and chemical properties on its potential and safe use. In the present work, a HA from a green compost was used along with three other materials of plant origin to remove two estrogens, 4-tert-octylphenol and 17-β-estradiol, and two pesticides, carbaryl and fenuron, from an aqueous solution. The four molecules were spiked in water each at a concentration of 1 mg L-1. The materials were: a biochar obtained from 100% red spruce pellet pyrolysed at 550 °C, spent coffee grounds and spent tea leaves. Kinetics curves and adsorption isotherms studies were performed using a batch equilibrium method. Adsorption data obtained for each compound were fitted to a linear equation and non-linear Freundlich and Langmuir models. Kinetics data of the four compounds onto all adsorbents showed an initial very rapid adsorption which was completed in few hours when it reached equilibrium. The two estrogens were adsorbed onto all materials more quickly than the two less hydrophobic pesticides. Significant differences among adsorbents and the

  20. Impact of humic acid on the photoreductive degradation of perfluorooctane sulfonate (PFOS) by UV/Iodide process.

    Science.gov (United States)

    Sun, Zhuyu; Zhang, Chaojie; Chen, Pei; Zhou, Qi; Hoffmann, Michael R

    2017-12-15

    Iodide photolysis under UV illumination affords an effective method to produce hydrated electrons (e aq - ) in aqueous solution. Therefore, UV/Iodide photolysis can be utilized for the reductive degradation of many recalcitrant pollutants. However, the effect of naturally occurring organic matter (NOM) such as humic and fulvic acids (HA/FA), which may impact the efficiency of UV/Iodide photoreduction, is poorly understood. In this study, the UV photoreductive degradation of perfluorooctane sulfonate (PFOS) in the presence of I - and HA is studied. PFOS undergoes a relatively slow direct photoreduction in pure water, a moderate level of degradation via UV/Iodide, but a rapid degradation via UV/Iodide/HA photolysis. After 1.5 h of photolysis, 86.0% of the initial [PFOS] was degraded in the presence of both I - and HA with a corresponding defluorination ratio of 55.6%, whereas only 51.7% of PFOS was degraded with a defluorination ratio of 4.4% via UV/Iodide illumination in the absence of HA. The relative enhancement in the presence of HA in the photodegradation of PFOS can be attributed to several factors: a) HA enhances the effective generation of e aq - due to the reduction of I 2 , HOI, IO 3 - and I 3 - back to I - ; b) certain functional groups of HA (i.e., quinones) enhance the electron transfer efficiency as electron shuttles; c) a weakly-bonded association of I - and PFOS with HA increases the reaction probability; and d) absorption of UV photons by HA itself produces e aq - . The degradation and defluorination efficiency of PFOS by UV/Iodide/HA process is dependent on pH and HA concentration. As pH increases from 7.0 to 10.0, the enhancement effect of HA improves significantly. The optimal HA concentration for the degradation of 0.03 mM PFOS is 1.0 mg L -1 . Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Coordination chemistry and hydrolysis of Fe(III) in a peat humic acid studied by X-ray absorption spectroscopy

    Science.gov (United States)

    Karlsson, Torbjörn; Persson, Per

    2010-01-01

    The speciation of iron (Fe) in soils, sediments and surface waters is highly dependent on chemical interactions with natural organic matter (NOM). However, the molecular structure and hydrolysis of the Fe species formed in association with NOM is still poorly described. In this study extended X-ray absorption fine structure (EXAFS) spectroscopy was used to determine the coordination chemistry and hydrolysis of Fe(III) in solution of a peat humic acid (5010-49,200 μg Fe g -1 dry weight, pH 3.0-7.2). Data were analyzed by both conventional EXAFS data fitting and by wavelet transforms in order to facilitate the identification of the nature of backscattering atoms. Our results show that Fe occurs predominantly in the oxidized form as ferric ions and that the speciation varies with pH and Fe concentration. At low Fe concentrations (5010-9920 μg g -1; pH 3.0-7.2) mononuclear Fe(III)-NOM complexes completely dominates the speciation. The determined bond distances for the Fe(III)-NOM complexes are similar to distances obtained for Fe(III) complexed by desferrioxamine B and oxalate indicating the formation of a five-membered chelate ring structure. At higher Fe concentrations (49,200 μg g -1; pH 4.2-6.9) we detect a mixture of mononuclear Fe(III)-NOM complexes and polymeric Fe(III) (hydr)oxides with an increasing amount of Fe(III) (hydr)oxides at higher pH. However, even at pH 6.9 and a Fe concentration of 49,200 μg g -1 our data indicates that a substantial amount of the total Fe (>50%) is in the form of organic complexes. Thus, in environments with significant amounts of organic matter organic Fe complexes will be of great importance for the geochemistry of Fe. Furthermore, the formation of five-membered chelate ring structures is in line with the strong complexation and limited hydrolytic polymerization of Fe(III) in our samples and also agrees with EXAFS derived structures of Fe(III) in organic soils.

  2. Effects of humic substances on the migration of radionuclides: Complexation of actinides with humic substances. (6th progress report, project summary). Period covered: January 1994 - July 1994

    International Nuclear Information System (INIS)

    Czerwinski, K.R.; Rhee, D.S.; Scherbaum, F.; Buckau, G.; Kim, J.I.; Moulin, V.; Tits, J.; Laszak, I.; Moulin, C.; Decambox, P.; Ruty, O. de; Marquardt, C.; Franz, C.; Herrmann, G.; Trautmann, N.; Dierckx, A.; Vancluysen, J.; Maes, A.; Bidoglio, G.; Eliet, V.; Grenthe, I.

    1995-03-01

    The goal of the research project is to examine the complexation behaviour of actinide ions with humic substances and thermodynamically describe the binding based upon a simple complexation model. This program is a continuation of the activities of the colloid and complexation group (COCO) in the second phase of the EC-MIRAGE project. A number of different experimental methods are used to determine speciation. The metal ions examined are the trivalent lanthanides, UO 2 2+ , NpO 2 + , Am 3+ , and Cm 3+ . The project is divided into three tasks: Task 1: complexation reactions of actinide ions with well characterized reference and site-specific humic and fulvic acids, Task 2: complexation reactions with major cations in natural groundwaters; Task 3: validation of the complexation data in natural aquatic systems by comparison of calculation with spectroscopic experiment. Five European community laboratories participated in the program: Technische Universitaet Muenchen, Commissariat a l'Energie Atomique Fontenay-Aux-Roses and Saclay, Universitaet Mainz, Katolieke Universiteit Leuven, and Joint Research Centre, Ispra. The evaluated stability constants are similar for all laboratories when the same humic substance complexation model is applied. Humic acid is shown to reduce NpO 2 + to Np 4+ , while no reduction of UO 2 2+ is observed. Temperature effects are seen on the Np humate complex. Competition is observed between NpO 2 + and Ca 2+ , but not between the trivalent lanthanides and Ca 2+ . No influence of humic acid purification on the evaluated stability constants is seen. Using the evaluated constants, calculations are conducted for natural water systems which indicate the trivalent actinide humate complex to be an important species. (orig.)

  3. INFLUENCE OF BORATE BUFFERS ON THE ELECTROPHORETIC BEHAVIOR OF HUMIC SUBSTANCES IN CAPILLARY ZONE ELECTROPHORESIS

    Science.gov (United States)

    The influence of tetrahydroxyborate ions on the electrophoretic mobility of humic acids was evaluated by capillary electrophoresis (CE). Depending on the molarity of borate ions in the separation buffer, the humic acids exhibit electropherograms with sharp peaks consistently exte...

  4. Interactions between radionuclides and organic colloids. Structure and reactivity of humic compounds

    International Nuclear Information System (INIS)

    Plancque, G.

    2001-09-01

    Humic compounds are the main organic colloids present in natural waters. These compounds can significantly modify the speciation of metals and control their properties, like migration, toxicity or bio-availability. It is thus important to study their speciation in conditions representative to those encountered in the natural environment. The aim of this work is to analyze the reactivity of these humic compounds. Two spectroscopic techniques have been used: the time-resolution laser spectro-fluorimetry, limited to the study of fluorescent elements, and the electro-spray source mass spectroscopy which requires the development of specific protocols for all elements of the periodic classification system. Europium, a fluorescent element analogue to trivalent actinides, has been chosen as test-metal for the intercomparison of both spectroscopic techniques. The first technique has permitted to determine the inorganic and organic speciation (spectra and lifetime of europium hydroxides and carbonates, and constants of interaction with humic acids, respectively). The limitations of this technique in the study of inorganic speciation has been evidenced. Humic compounds have a badly defined structure. The use of high-resolution mass spectroscopy has permitted to propose in a direct and experimental way, a molecular structure of aquatic fulvic acids in agreement with their known physico-chemical properties. (J.S.)

  5. Phytochemical and Morphological Attributes of St. John’s Wort (Hypericum perforatum Affected by Organic and Inorganic Fertilizers; Humic Acid and Potassium Sulphate

    Directory of Open Access Journals (Sweden)

    Helaleh Sadat KABOLI FARSHCHI

    2014-09-01

    Full Text Available This experiment was designed to evaluate the effects of organic (liquid humic acid and inorganic (potassium sulphate on phytochemical and morphological attributes of St. John’s Wort (Hypericum perforatum. Thus, a research was conducted in a factorial experiment (3×3 based on completely randomized design with three replications. Treatments consisted of potassium sulphate (Kx at three concentrations (0, 60 and 100 Kg/h which were treated before flowering and humic acid (Hx at three concentrations (0, 20 and 40 L/h which were fertigated four times of 15-days intervals. Results showed that the plant stem height, number of flowering stems and number of flowers were significantly affected by simple effect of each fertilizers (p<0.01, while their interaction effect was not significant for the plants height. The highest contents of fresh and dry weight were achieved under the highest amounts of fertilizers (K100 and H40. The highest stem height, number of flowers and number of flowering stems also belonged to these treatments. Increment of applied fertilizers led to increase of obtained essential oils, so that application of these fertilizers simultaneously increased the essential oil content up to 6-fold. Regarding the antioxidant activity, applied fertilizers at their high levels showed significant effects on decrease of EC50, which means the increment of antioxidant activity of H. perforatum.

  6. Effect of pH, temperature, humic acid and coexisting anions on reduction of Cr(Ⅵ) in the soil leachate by nZVI/Ni bimetal material.

    Science.gov (United States)

    Zhu, Fang; Li, Luwei; Ren, Wentao; Deng, Xiaoqiang; Liu, Tao

    2017-08-01

    Nano zero valent iron/Ni bimetal materials (nZVI/Ni) were prepared by borohydride reduction method to remediate toxic Cr(Ⅵ) contaminated in soil leachate. nZVI/Ni was characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray Photoelectron Spectroscopy (XPS). Different factors including pH value of soil leachate, reaction time, temperature, humic acid and coexisting anions (SO 4 2- , NO 3 - , HCO 3 - , CO 3 2- ) were studied to analyze the reduction rate. Results showed that the reduction rate of Cr(Ⅵ) could reach 99.84% under the condition of pH of 5 and temperature of 303 K. pH values and temperature of soil leachate had a significant effect on the reduction efficiency, while humic acid had inhibition effect for the reduction reaction. SO 4 2- , HCO 3 - and CO 3 2- had inhibition effect for reduction rate, while NO 3 - barely influenced the reduction process of nZVI/Ni. Moreover, Langumir-Hinshelwood first order kinetic model was studied and could describe the reduction process well. The thermodynamic studies indicated that the reaction process was endothermic and spontaneous. Activation energy was 143.80 kJ mol -1 , showing that the reaction occurred easily. Therefore, the study provides an idea for nZVI/Ni further research and practical application of nZVI/Ni in soil remediation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. CHARACTERIZATION OF SORBENT PRODUCED THROUGH IMMOBILIZATION OF HUMIC ACID ON CHITOSAN USING GLUTARALDEHYDE AS CROSS-LINKING AGENT AND Pb(II ION AS ACTIVE SITE PROTECTOR

    Directory of Open Access Journals (Sweden)

    Uripto Trisno Santoso

    2010-12-01

    Full Text Available Sorbent produced through immobilization of humic acid (HA on chitosan using glutaraldehyde as cross-linking agent and Pb(II ions as active site protector has been characterized. Active sorption site of HA was protected by reacting HA with Pb(II ion, and the protected-HA was then activated by glutaraldehyde, crosslinked onto chitosan, and deprotected by 0.1 M disodium ethylenediamine tetra-acetic acid (Na2EDTA. The protected-crosslinking method enhanced the content of immobilized-HA and its chemical stability. Based on the FTIR spectra, crosslinking of HA on chitosan probably occurred through a chemical reaction. The sorption capacity of sorbent still remains unchanged after the second regeneration, but some of HA start to be soluble. The latter shows that cross-linking reaction between HA and chitosan is through formation an unstable product. The effectiveness of sorbent regeneration can also be identified by the XRD pattern.

  8. Analysis of electrophoretic soil humic acids fractions by reversed-phase high performance liquid chromatography with on-line absorbance and fluorescence detection.

    Science.gov (United States)

    Trubetskoj, Oleg A; Richard, Claire; Guyot, Ghislain; Voyard, Guillaume; Trubetskaya, Olga E

    2012-06-22

    A combination of reversed-phase high performance liquid chromatography (RP HPLC) with on-line absorbance and fluorescence detection was used for analysis of chernozem soil humic acids (HAs) and their fractions A, B and C+D with different electrophoretic mobility (EM) and molecular size (MS). Samples were injected onto the column at the identical volume and absorbance. All chromatograms exhibit the resolution of seven peaks. The estimation of relative recovery of HAs and fractions from the reverse-phase column has been done. High MS fraction A, which possesses the low EM, is essentially more hydrophobic (73% of the fraction amount remained adsorbed on the column) and aliphatic than medium MS and EM fraction B (33% of the fraction amount remained adsorbed on the column). The most hydrophilic and aromatic properties belong to low MS fraction C+D, which possess the highest EM and practically was not adsorbed on the column. The hydrophobicity of the bulk HAs lies within the range of fractions hydrophobicity. The absorption spectra of bulk HAs, electrophoretic fractions A, B, C+D and corresponding RP HPLC peaks were featureless but had differences in the values of absorbance ratio at 300 and 400 nm (A3/A4). For fractions A and B this ratio gradually decreased from peak 1 to 7 (from 3.05 to 2.80 and 3.00 to 2.40, respectively). This trend was less pronounced in HAs and practically absent in fraction C+D, where ratio A3/A4 varied within a small range. The strong relationship between fluorescence properties, EM, MS, polarity and aliphaticity/aromaticity of HAs fractions was found. Humic and protein-like fluorescence had different polarity nature. The protein-like fluorescence is located in humic material which irreversibly adsorbed on the reverse-phase column and not subjected to RP HPLC characterization. The humic-like fluorescence at Ex/Em 270/450 nm is mostly located in the hydrophilic peak of low MS fraction C+D. Taking into account that high MS fraction A consisted

  9. Characterization of Nanoparticles and Colloids in Aquatic Systems 1. Small Angle Neutron Scattering Investigations of Suwannee River Fulvic Acid Aggregates in Aqueous Solutions

    International Nuclear Information System (INIS)

    Diallo, Mamadou S.; Glinka, Charles J.; Goddard, William A.; Johnson, James H.

    2005-01-01

    Fulvic acids (FA) and humic acids (HA) constitute 30-50% of dissolved organic matter in natural aquatic systems. In aqueous solutions, a commonly accepted view is that FA and HA exist as soluble macroligands at low concentration and as supramolecular aggregates at higher concentration. The size, shape and structure of these aggregates are still the subject of ongoing debate in the environmental chemistry literature. In this article, we use small angle neutron scattering (SANS) to assess the effects of solute concentration, solution pH and background electrolyte (NaCl) concentration on the structures of Suwannee River FA (SRFA) aggregates in D 2 O. The qualitative features of the SANS curves and data analysis are not consistent with the view point that SRFA forms micelle-like aggregates as its concentration in aqueous solution increases. We find that SRFA forms fractal aggregates in D 2 0 with size greater than 242 nm. The SRFA aggregates undergo a significant degree of restructuring in compactness as solution pH, solute concentration and NaCl concentration increase

  10. Sorption of Aldrich humic acid onto hematite: Insights into fractionation phenomena by electro-spray ionization with quadrupole time-of-flight mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Reiller, Pascal; Amekraz, Badia; Moulin, Christophe [CEA, CE Saclay, Nuclear Energy Division, DANS/DPC/SECR, Laboratoire de Speciation des Radionucleides et des Molecules, Batiment 391, BP 11, F-91191 Gif sur Yvette Cedex (France)

    2006-07-01

    Sorption induced fractionation of purified Aldrich humic acid (PAHA) on hematite is studied through the modification of electro-spray ionization (ESI) quadrupole time-of-flight (QToF) mass spectra of supernatants from retention experiments. The ESI mass spectra show an increase of the 'mean molecular masses' of the molecules that constitutes humic aggregates. The low molecular weight fraction (LMWF; m/z {<=} 600 Da) is preferentially sorbed compared to two other fractions. The resolution provided by ESI-QToF mass spectrometer in the low-mass range provided evidence of further fractionation induced by sorption within the LMWF. Among the two latter fractions, the high molecular weight fraction (HMWF; m/z {approx_equal} 1700 Da) seems to be more prone to sorption compared to the intermediate molecular weight fraction (IMWF; m/z {approx_equal} 900 Da). The IMWF seems to be more hydrophilic as it should be richer in O, N, and alkyl C from the proportion of even mass, and poorer in aromatic structures from mass defect analysis in ESI mass spectra. (authors)

  11. Association of 16 priority polycyclic aromatic hydrocarbons with humic acid and humin fractions in a peat soil and implications for their long-term retention.

    Science.gov (United States)

    Chen, Weixiao; Wang, Hui; Gao, Qian; Chen, Yin; Li, Senlin; Yang, Yu; Werner, David; Tao, Shu; Wang, Xilong

    2017-11-01

    To elucidate the environmental fate of polycyclic aromatic hydrocarbons (PAHs) once released into soil, sixteen humic acids (HAs) and one humin (HM) fractions were sequentially extracted from a peat soil, and sixteen priority PAHs in these humic substances (HSs) were analyzed. It was found that the total concentration of 16 PAHs (∑16PAHs) increased evidently from HA1 to HA16, and then dramatically reached the highest value in HM. The trend of ∑16PAHs in HAs relates to surface carbon and C-H/C-C contents, the bulk aliphatic carbon content and aliphaticity, as well as the condensation enhancement of carbon domains, which were derived from elemental composition, XPS, 13 C NMR, as well as thermal analyses. HM was identified to be the dominant sink of 16 PAHs retention in soil, due to its aliphatic carbon-rich chemical composition and the highly condensed physical makeup of its carbon domains. This study highlights the joint roles of the physical and chemical properties of HSs in retention of PAHs in soil and the associated mechanisms; the results are of significance for PAH-polluted soil risk assessment and remediation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Polymerin and lignimerin, as humic acid-like sorbents from vegetable waste, for the potential remediation of waters contaminated with heavy metals, herbicides, or polycyclic aromatic hydrocarbons.

    Science.gov (United States)

    Capasso, Renato; De Martino, Antonio

    2010-10-13

    Polymerin is a humic acid-like polymer, which we previously recovered for the first time from olive oil mill waste waters (OMWW) only, and chemically and physicochemically characterized. We also previously investigated its versatile sorption capacity for toxic inorganic and organic compounds. Therefore, a review is presented on the removal, from simulated polluted waters, of cationic heavy metals [Cu(II), Zn, Cr(III)] and anionic ones [Cr(VI)) and As(V)] by sorption on this natural organic sorbent in comparison with its synthetic derivatives, K-polymerin, a ferrihydrite-polymerin complex and with ferrihydrite. An overview is also performed of the removal of ionic herbicides (2,4-D, paraquat, MCPA, simazine, and cyhalofop) by sorption on polymerin, ferrihydrite, and their complex and of the removal of phenanthrene, as a representative of polycyclic aromatic hydrocarbons, by sorption on this sorbent and its complexes with micro- or nanoparticles of aluminum oxide, pointing out the employment of all these sorbents in biobed systems, which might allow the remediation of water and protection of surface and groundwater. In addition, a short review is also given on the removal of Cu(II) and Zn from simulated contaminated waters, by sorption on the humic acid-like organic fraction, named lignimerin, which we previously isolated for the first time, in collaboration with a Chilean group, from cellulose mill Kraft waste waters (KCMWW) only. More specifically, the production methods and the characterization of the two natural sorbents (polymerin and lignimerin) and their derivatives (K-polymerin ferrihydrite-polymerin, polymerin-microAl(2)O(3) and -nanoAl(2)O(3), and H-lignimerin, respectively) as well as their sorption data and mechanism are reviewed. Published and original results obtained by the cyclic sorption on all of the considered sorbents for the removal of the above-mentioned toxic compounds from simulated waste waters are also reported. Moreover, sorption capacity

  13. The Effect of Humic Acid Applications on Some Morphological, Physiological and Biochemical Characteristics of Eggplants Irrigated with Water Contained Heavy Metals in High Concentration

    Directory of Open Access Journals (Sweden)

    Sevinc Kiran

    2014-06-01

    Full Text Available In this study, it was aimed to demonstrate the effect of humic acid applications on some morphological, physiological and biochemical characteristics of eggplant genotypes (Burdur Merkez, Burdur Bucak, Kemer and Giresun irrigated with the irrigation water with a high content of heavy metal and determined previously salt tolerance levels. In studies conducted in controlled greenhouse conditions, eggplant seeds germinated in the growth substrate a mixture of peat and perlite and the seedlings were transplanted into pots at 20 days after sowing. Plants when they are 4-5 true leaves, 3 different humic acid levels (0, 500, 1000 ppm have been applied and 7 days later after this application began to be watered with 3 different irrigation water comprising a mixture of various doses of heavy metals (control: 0 ppm; I. Mixture: 0.2 ppm 5 ppm to 0.01 ppm Cd + Cu + Pb + 2 ppm Zn, II. mixture: +0.02 ppm 0.4 ppm Cu 10 ppm Pb + Cd + 4 ppm Zn. Field capacity level for the plants 40 days after quenched with water after which time they were harvested and samples for analysis were performed. In the study plants were investigated for shoot and root fresh weight, shoot and root dry weight, shoot and root length, leaf area, chlorophyll and MDA level of superoxide dismutase (SOD, catalase (CAT, ascorbate peroxidase (APX and glutathione reductase (GR enzyme activities All genotypes are adversely affected by heavy metal applications. In parallel to increase the dose, heavy metal mixtures led to a reduction in values of fresh and dry weight of shoot and root, stem and root length, leaf area of eggplant genotypes. MDA and antioxidative enzyme activities increased in plants irrigated with water containing a mixture of heavy metal. Humic acid applications had a positive effect on reducing of the limiting effect of heavy metal stress on growth and development. As a result, compared to sensitive genotypes Giresun and Kemer, salt tolerant genotypes Burdur Merkez and Burdur

  14. Biodegradation of dissolved humic substances by fungi.

    Science.gov (United States)

    Collado, Sergio; Oulego, Paula; Suárez-Iglesias, Octavio; Díaz, Mario

    2018-04-01

    Humic and fulvic acids constitute humic substances, a complex mixture of many different acids containing carboxyl and phenolate groups, which are not only the principal soil fertility factors but also the main pollutants present in landfill leachates or natural organic matter in water. Due to their low bacterial biodegradability, fungal biodegradation processes are key for their removal. The present study compiles and comments all the available literature on decomposition of aqueous humic substances by fungi or by their extracellular enzymes alone, focusing on the influence of the reaction conditions. The biodegradation extent mainly depends on the characteristics and concentration of the humic compounds, the type of microorganisms selected, the inoculation mode, the C and N sources, the presence of certain chemicals in the medium, the availability of oxygen, the temperature, and the pH.

  15. Haloacetic acids in the aquatic environment. Part II: ecological risk assessment

    International Nuclear Information System (INIS)

    Hanson, Mark L.; Solomon, Keith R.

    2004-01-01

    Haloacetic acids (HAAs) are environmental contaminants found in aquatic ecosystems throughout the world as a result of both anthropogenic and natural production. The ecological risk posed by these compounds to organisms in freshwater environments, with a specific focus on aquatic macrophytes, was characterized. The plants evaluated were Lemna gibba, Myriophyllum spicatum and M. sibiricum and the HAAs screened were monochloroacetic acid (MCA), dichloroacetic acid (DCA), trichloroacetic acid (TCA), trifluoroacetic acid (TFA) and chlorodifluoroacetic acid (CDFA). Laboratory toxicity data formed the basis of the risk assessment, but field studies were also utilized. The estimated risk was calculated using hazard quotients (HQ), as well as effect measure distributions (EMD) in a modified probabilistic ecological risk assessment. EMDs were used to estimate HAA thresholds of toxicity for use in HQ assessments. This threshold was found to be a more sensitive measure of low toxicity than the no observed effect concentrations (NOEC) or the effective concentration (EC 10 ). Using both deterministic and probabilistic methods, it was found that HAAs do not pose a significant risk to freshwater macrophytes at current environmental concentrations in Canada, Europe or Africa for both single compound and mixture exposures. Still, HAAs are generally found as mixtures and their potential interactions are not fully understood, rendering this phase of the assessment uncertain and justifying further effects characterization. TCA in some environments poses a slight risk to phytoplankton and future concentrations of TFA and CDFA are likely to increase due to their recalcitrant nature, warranting continued environmental surveillance of HAAs. - Current environmental concentrations of haloacetic acids do not pose a risk to aquatic macrophytes, but could impact plankton

  16. Evaluation of adsorption capacities of humic acids extracted from Algerian soil on polyaniline for application to remove pollutants such as Cd(II), Zn(II) and Ni(II) and characterization with cavity microelectrode.

    Science.gov (United States)

    Terbouche, Achour; Ramdane-Terbouche, Chafia Ait; Hauchard, Didier; Djebbar, Safia

    2011-01-01

    The adsorption capacities of new humic acids isolated from Yakouren forest (YHA) and Sahara (Tamenrasset: THA) soils (Algeria) and commercial humic acid (PFHA) on polyaniline emeraldine base (PEB) were studied at pH 6.6. Also the adsorption of heavy metals such as Cd2+, Zn2+ and Ni2+ on humic acid-polyaniline systems (HA-PEB) was investigated at the same conditions. HA-PEB compounds were characterized by scanning electron microscopy (SEM), infrared spectrometry and cavity microelectrode. In addition, batch adsorption and cavity microelectrode were used in the adsorption study of Cd2+, Zn2+ and Ni2+ on HA-PEB. To develop biocaptors of polluting metals using a cavity microelectrode modified by HA-PEB systems, the adsorption kinetic and adsorption capacity were investigated. The SEM analysis showed that the presence of humic acid affected the PEB surface and caused the formation of a granular morphology. The maximum adsorption capacities (q(max)) of PFHA, THA and YHA determined by adsorption isotherms were 91.31, 132.1 and 151.0 mg/g, respectively. Batch adsorption results showed that q(max) of Cd2+, Zn2+ and Ni2+ on HA-PEB followed the order: THA-PEB > YHA-PEB > PFHA-PEB. The voltammograms obtained with HA-PEB modified cavity microelectrode showed the appearance of new redox couples reflecting the adsorption of HA on PEB. Metal-humic acid-polyaniline voltammograms were characterized by appearance of oxidation-reduction couples or reduction wave corresponding to metal. Finally, the result may be exploited to develop a biocaptor based on the cavity microelectrode amended by THA-PEB and YHA-PEB.

  17. Photodegradation of lambda-cyhalothrin and cypermethrin in aqueous solution as affected by humic acid and/or copper: intermediates and degradation pathways.

    Science.gov (United States)

    Xie, Jimin; Wang, Pingli; Liu, Jun; Lv, Xiaomeng; Jiang, Deli; Sun, Cheng

    2011-11-01

    The influence of coexisting humic acids (HA) or Cu²⁺ on the photodegradation of pesticides lambda-cyhalothrin (λ-CHT) and cypermethrin (CPM) in aqueous solution was studied under xenon lamp irradiation. The removal efficiency of pesticides λ-CHT and CPM were enhanced in the presence of either Cu²⁺ or HA but restrained in the presence of both Cu²⁺ and HA. The photodegradation of λ-CHT and CPM followed first-order reaction kinetics. The photodegradation intermediates of λ-CHT and CPM were determined using gas chromatography/mass spectrometry. Possible photodegradation pathways included decarboxylation, ester bond cleavage, dechlorination, and phenyl group removal. Copyright © 2011 SETAC.

  18. Particle phase distribution of polycyclic aromatic hydrocarbons in stormwater — Using humic acid and iron nano-sized colloids as test particles

    DEFF Research Database (Denmark)

    Nielsen, Katrine; Kalmykova, Yuliya; Strömvall, Ann-Margret

    2015-01-01

    The distribution of polycyclic aromatic hydrocarbons (PAHs) in different particulate fractions in stormwater: Total, Particulate, Filtrated, Colloidal and Dissolved fractions, were examined and compared to synthetic suspensions of humic acid colloids and iron nano-sized particles. The distribution...... to a higher extent in the Filtrated fractions. The highest concentrations of PAHs were present in the stormwater with the highest total suspended solids (TSS); the relative amount of the HMWPAHs was highest in the Particulate fractions (particles N 0.7 μm). The highest concentration of PAHs in the Colloidal...... fraction was found in the sample with occurrence of small nano-sized particles (b10 nm). The results show the importance of developing technologies that both can manage particulate matter and effectively remove PAHs present in the Colloidal and Dissolved fractions in stormwater. © 2015 Elsevier B.V. All...

  19. Tracing carbon sources through aquatic and terrestrial food webs using amino acid stable isotope fingerprinting.

    Directory of Open Access Journals (Sweden)

    Thomas Larsen

    Full Text Available Tracing the origin of nutrients is a fundamental goal of food web research but methodological issues associated with current research techniques such as using stable isotope ratios of bulk tissue can lead to confounding results. We investigated whether naturally occurring δ(13C patterns among amino acids (δ(13CAA could distinguish between multiple aquatic and terrestrial primary production sources. We found that δ(13CAA patterns in contrast to bulk δ(13C values distinguished between carbon derived from algae, seagrass, terrestrial plants, bacteria and fungi. Furthermore, we showed for two aquatic producers that their δ(13CAA patterns were largely unaffected by different environmental conditions despite substantial shifts in bulk δ(13C values. The potential of assessing the major carbon sources at the base of the food web was demonstrated for freshwater, pelagic, and estuarine consumers; consumer δ(13C patterns of essential amino acids largely matched those of the dominant primary producers in each system. Since amino acids make up about half of organismal carbon, source diagnostic isotope fingerprints can be used as a new complementary approach to overcome some of the limitations of variable source bulk isotope values commonly encountered in estuarine areas and other complex environments with mixed aquatic and terrestrial inputs.

  20. The humic acid-induced changes in the water status, chlorophyll fluorescence and antioxidant defense systems of wheat leaves with cadmium stress.

    Science.gov (United States)

    Ozfidan-Konakci, Ceyda; Yildiztugay, Evren; Bahtiyar, Mustafa; Kucukoduk, Mustafa

    2018-07-15

    The using of bio-stimulant in plants grown under stress conditions for enhancing nutrition efficiency and crop quality traits is an effective approach. One of the bio-stimulants, humus material, is defined as humic acid (HA). HA application as a promotion of plant growth to plants grown in the heavy metals-contaminated soils has promised hope in terms of effects on plants but the its limiting effect is the application dose. Therefore, the wheat seedlings were grown in hydroponic culture for 21 d and the various concentrations of humic acid (HA; 750 or 1500 mg L -1 ) were treated alone or in combination with cadmium (Cd) stress (100 or 200 μM) for 7 d. The results showed that after Cd stress treatment, water content (RWC), osmotic potential (Ψ Π ) and chlorophyll fluorescence parameters decreased and proline content (Pro) increased for 7 d. In spite of activated peroxidase (POX) and ascorbate peroxidase (APX), stress induced the toxic levels of hydrogen peroxide (H 2 O 2 ) accumulation. Cd stress triggered lipid peroxidation (TBARS content). HA application successfully eliminated the negative effects of stress on RWC, Ψ Π and photosynthetic parameters. In the presence of HA under stress, the increased activation of superoxide dismutase (SOD), catalase (CAT) and NADPH-oxidase (NOX) enzymes and ascorbate, glutathione and GSH/GSSG ratio observed. Only 750 mg L -1 HA under stress conditions induced the activities of monodehydroascorbate reductase (MDHAR) and dehydroascorbate reductase (DHAR), and dehydroascorbate (DHA) content. After the combined application of HA and Cd stress, the low contents of H 2 O 2 and TBARS maintained in wheat leaves. Hence, HA successfully eliminated the toxicity of Cd stress by modulating the water status, photosynthetic apparatus and antioxidant activity in wheat leaves. Copyright © 2018 Elsevier Inc. All rights reserved.

  1. Stability and aggregation of nanoscale titanium dioxide particle (nTiO2): Effect of cation valence, humic acid, and clay colloids.

    Science.gov (United States)

    Tang, Zhong; Cheng, Tao

    2018-02-01

    Fate and transport of engineered nanoscale titanium dioxide (nTiO 2 ) have received much attention during the past decade. The aggregation and stability of nTiO 2 in water with complicated components, however, have not been fully examined. The objective of this paper is to determine the individual and synergistic effect of cation valence, humic acid, and clay colloids on nTiO 2 stability and aggregation, and elucidate the related mechanisms. We conducted systematic laboratory experiments to determine nTiO 2 stability and aggregation in NaCl and MgCl 2 solutions, both in the absence and presence of humic acid and illite colloids. Results showed that Mg 2+ , in comparison to Na + , could make the zeta potential of nTiO 2 more positive, and shift the point of zero charge of nTiO 2 (pH pzc,TiO2 ) towards higher pH. We also found that nTiO 2 are destabilized by illite colloids at pH < pH pzc,TiO2 through formation of illite-nTiO 2 hetero-aggregates, but are not interfered by illite colloids at higher pH. HA was found to make nTiO 2 stable via electrostatic and steric effects, both in the absence and presence of illite colloids. Calculated interaction energy based on DLVO theory revealed that instability of the nTiO 2 suspensions is mainly caused by primary minima, and that secondary minima normally do not destabilize the suspension, even though they are found to promote aggregation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. History-dependent sorption in humic acids and a lignite in the context of a polymer model for natural organic matter.

    Science.gov (United States)

    Lu, Yuefeng; Pignatello, Joseph J

    2004-11-15

    We examined sorption of two apolar compounds in three samples of macromolecular natural organic matter (NOM) in order to test whether history-dependent ("irreversible") behaviors, including sorption hysteresis and the conditioning effect, agree with a pore deformation/creation hypothesis applicable to the glassy organic solid state as proposed in the polymer literature. The compounds are 1,2,4-trichlorobenzene (TCB) and naphthalene (Naph). The NOM samples are a soil humic acid (H-HA), an Al3+-exchanged form of the same humic acid (Al-HA), and a low-rank coal (Beulah-Zap lignite, BZL). The HAs, at least, are believed free of environmental black carbon. The degree of nonlinearity in the isotherm and the ratio of hole-filling to solid-phase dissolution increased in the order of hardness (stiffness) of the solid: H-HA hole "sites" as compared to dissolution "sites", which we attribute to the free energy needed in the dissolution domain to create a cavity to accommodate the solute. All solids exhibited hysteresis and the conditioning effect, which refers to enhanced re-sorption after pretreatment with a conditioning agent (in this case, chlorobenzene). Conditioning the sample results in increased sorption and increased contribution of hole-filling relative to dissolution. The effects of original hole population, matrix stiffness, and solute concentration on the hysteresis index and on the magnitude of the conditioning effect are consistent with a pore-deformation mechanism as the underlying cause of sorption irreversibility. This mechanism involves concurrent processes of irreversible hole expansion and the creation of new holes by the incoming sorbate (or conditioning agent). The results show that nonlinear and irreversible behavior may be expected for macromolecular forms of NOM that are in a glassy state and emphasize the case that NOM is not a passive sorbent but may be physically altered by the sorbate.

  3. Amino acid- vs. peptide-odorants: responses of individual olfactory receptor neurons in an aquatic species.

    Directory of Open Access Journals (Sweden)

    Thomas Hassenklöver

    Full Text Available Amino acids are widely used waterborne olfactory stimuli proposed to serve as cues in the search for food. In natural waters the main source of amino acids is the decomposition of proteins. But this process also produces a variety of small peptides as intermediate cleavage products. In the present study we tested whether amino acids actually are the natural and adequate stimuli for the olfactory receptors they bind to. Alternatively, these olfactory receptors could be peptide receptors which also bind amino acids though at lower affinity. Employing calcium imaging in acute slices of the main olfactory epithelium of the fully aquatic larvae of Xenopus laevis we show that amino acids, and not peptides, are more effective waterborne odorants.

  4. Aquatic predicted no-effect-concentration derivation for perfluorooctane sulfonic acid.

    Science.gov (United States)

    Qi, Ping; Wang, Ying; Mu, Jingli; Wang, Juying

    2011-04-01

    Perfluorooctane sulfonic acid (PFOS), a representative perfluorinated surfactant, is an anthropogenic pollutant detected in various environmental and biological matrices. Some laboratory and field work has been conducted to assess the aquatic toxicity of PFOS, but little is known regarding its toxicity threshold to the aquatic ecosystem. In the present study, predicted no-effect concentrations (PNECs) were derived by four different approaches. The interspecies correlation estimation (ICE) program and final acute-to-chronic ratio (FACR) were applied to the development of PNEC based on the toxic mode of action (MOA) of PFOS. By comparison of the different PNECs, the recommended aquatic toxicity thresholds for PFOS are in the range of 0.61 to 6.66 µg/L. Based on comparison of PNEC values, microcosm results, and reported environmental concentrations, PFOS appears not to pose a serious threat to aquatic organisms. The present results demonstrate that MOA is an important consideration for the derivation of reliable PNECs; moreover, the ICE-based species sensitivity distribution (SSD) method can be used to derive PNECs when toxicological data are limited. The application of MOA and ICE for deriving PNEC values in the present study may facilitate studies on using a combination of quantitative structure-activity relationship (QSAR) models and ICE to estimate PNECs. Copyright © 2011 SETAC.

  5. Yields of potato and alternative crops impacted by humic product application

    Science.gov (United States)

    Humic substance (HA—humic acid, fulvic acid, and humin) are a family of organic molecules made up of long carbon chains and numerous active functional groups such as phenols and other aromatics. Humic substances play dynamic roles in soil physical, chemical biological functions essential to soil he...

  6. Chemical modeling of boron adsorption by humic materials using the constant capacitance model

    Science.gov (United States)

    The constant capacitance surface complexation model was used to describe B adsorption behavior on reference Aldrich humic acid, humic acids from various soil environments, and dissolved organic matter extracted from sewage effluents. The reactive surface functional groups on the humic materials wer...

  7. Evaluation of Some Agroecological Characteristics of Basil (Ocimum basilicum L. as Affected by Simultaneous Application of Water-Saving Superabsorbent Hydrogel in Soil and Foliar Application of Humic Acid under Different Irrigation Intervals in a Low Inp

    Directory of Open Access Journals (Sweden)

    M. Jahan

    2016-02-01

    Full Text Available Introduction: Basil (Ocimum basilicum L. is an annual herbaceous plant that belongs to lamiaceae family. This plant is native of India country and other countries in south of Asia. Nowadays, the use of water superabsorbent polymers is increased in agriculture and their role in reducing the drought stress and increasing the crops production has been demonstrated in many researches. Superabsorbent polymers can absorb lots of water and keep it in their structure and give it to plant under drought stress conditions (9. Humic substances are a group of heterogeneous molecules that are bonded together by weak forces, therefore they have high chemical stability. Humic acid comprise 65 to 80 percent of total soil organic matter (6. According to medicinal importance of Basil and its roles in the food and pharmaceutical industries, beside the limited water resources and need to increase water use efficiency through using ecological inputs, this study designed and conducted aimed to evaluate agroecological characteristics of Basil as affected by application of water-saving superabsorbent and humic acid under irrigation intervals. Materials and Methods: In order to evaluate the effects of different amounts of water-saving superabsorbent and foliar application of humic acid and irrigation intervals on some quantitative characteristics of basil (Ocimum basilicum L., a split strip plot experiment was conducted based on RCBD design with three replications at The Research Farm of Ferdowsi University of Mashhad, Iran during growing season of 2012-13. Experimental factors included three levels of water-saving superabsorbent (0, 40 and 80 kg ha-1 as the main plot factor, two levels of humic acid (0 and 3 kg ha-1 as the sub plot factor and two levels of irrigation interval (5 and 10 days as the strip plot factor. Studied traits were seed number and weight per plant, plant height, number of lateral branches per plant, seed yield, biological yield and harvest index

  8. Effects of humic substances on the migration of radionuclides: Complexation of actinides with humic substances. 1. progress report

    International Nuclear Information System (INIS)

    Kim, J.I.; Buckau, G.; Klenze, R.; Rhee, D.S.; Wimmer, H.; Decambox, P.; Mauchien, P.; Moulin, C.; Moulin, V.; Tits, J.; Marquardt, C.; Riegel, J.; Sattelberger, P.; Herrmann, G.; Trautmann, N.; Diercks, A.; Vancluysen, J.; Maes, A.; Bidoglio, G.; Righetto, L.

    1992-02-01

    The aim of the present research programme is to study the complexation behaviour of actinide ions with humic substances in natural aquifer systems and hence to quantify the effect of humic substances on the actinide migration. Aquatic humic substances commonly found in all groundwaters in different concentrations have a strong tendency towards complexation with actinide ions. This is one of the major geochemical reactions but hitherto least quantified. Therefore, the effect of humic substances on the actinide migration is poorly understood. In the present research programme the complexation of actinide ions with humic substances will be described thermodynamically. This description will be based on a model being as simple as possible to allow an easy introduction of the resulting constants into geochemical modelling of the actinide migration. This programme is a continuation of the activities of the COCO group in the second phase of the CEC-MIRAGE project. (orig.)