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Sample records for humic acids enhances

  1. Effect of Enhancing Urea-Humic Acid Mixture with Refined Acid Sulphate Soil

    OpenAIRE

    Mohd T.M. Yusuff; Osumanu H. Ahmed; Nik M.A. Majid

    2009-01-01

    Problem statement: Acid Sulphate Soil (ASS) is a problem soil partly because of its high acidity. This low pH could be exploited to reduce ammonia loss from urea by reducing soil microsite pH. The use Humic Acid (HA) to control ammonia loss from urea has been reported but the cost of this material is high. This laboratory study compared the effect of enhancing urea-humic acid mixtures with acid sulphate soil on NH3 loss, pH, exchangeable ammonium and available nitrate contents. Approach: Humi...

  2. [Comparison study of enhanced coagulation on humic acid and fulvic acid removal].

    Science.gov (United States)

    Zhou, Ling-ling; Zhang, Yong-ji; Ye, He-xiu; Zhang, Yi-qing

    2012-08-01

    Enhanced coagulation effects of four coagulants, such as aluminium sulfate, ferric chloride, aluminium polychloride and poly-ferric chloride, were examined, with an emphasis on pH, turbidity, Ca+ and relative contents of humic acid and fulvic acid. The result showed that the removal efficiency of four kinds of coagulant for humic acid was higher than that for fulvic acid. Compared with aluminium polychloride and poly-ferric chloride, aluminium sulfate and ferric chloride possessed a better coagulation effect. At the coagulant dosage of 40 mg x L(-1), ferric chloride, aluminium sulfate, poly-ferric chloride and aluminium polychloride removed fulvic acid from 10 mg x L(-1) to 3.22 mg x L(-1), 4.34 mg x L(-1), 5.85 mg x L(-1) and 4.86 mg x L(-1) respectively, while the four coagulants removed humic acid from 10 mg x L(-1) to 1.13 mg x L(-1), 2.13 mg x L(-1), 3.44 mg x L(-1) and 2.50 mg x L(-1) respectively in water. At pH between 5.5 and 6.5, aluminium sullfate and ferric chloride had the best coagulation effect. The coagulant had the lower efficiency with increase of organic carbon in water. Especially, the content ratio of fulvic acid and humic acid was above 0.4, the coagulation effect markedly decreased. Turbidity has a little influence on organic carbon removal rate. With the concentration of Ca2+, the removal efficiency of humic acid and fulvic acid increased.

  3. 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

  4. Interaction between humic acids and anthraquinone dyes

    Energy Technology Data Exchange (ETDEWEB)

    Shinozuka, N.; Lee, C. (The University of Tokyo, Tokyo (Japan). Institute of Industrial Science)

    1991-08-20

    Interactions between humic acids and anthraquinone disperse-dyes were studied. A humic acid extracted from a marine sediment and a commercial one were used to solubilized dyes sparingly soluble in water. The dye solubility in humic acid solution increases with humic acid concentration and enhancement was marked for solution of Aldrich humic acid. The addition of salts decreased the solubility of the dye. But the effects were complicated. Dye solubility increased with temperature. Especially, in the case of a 0.1% solution of marine humic acid at high temperature, the solubility increased. The spectrum of the dye were changed by solubilization in humic acid solution, and a twin peak characteristics of 1,4-isomers of polyaminoanthraquinone disappeared and a broad peak appeared. The dye solubilized by humic acid may thus possibly exist as a solid state as a deposit on quartz. 23 refs., 3 figs., 3 tabs.

  5. Humic acid protein complexation

    OpenAIRE

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

    2008-01-01

    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 ...

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

    Science.gov (United States)

    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. Copyright © 2012 Elsevier Ltd. All rights reserved.

  7. Effect of humic acid on sorption of technetium by alumina

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, S.; Rawat, N.; Kar, A.S. [Radiochemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085, Maharastra (India); Tomar, B.S., E-mail: bstomar@barc.gov.in [Radiochemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085, Maharastra (India); Manchanda, V.K. [Radiochemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085, Maharastra (India)

    2011-09-15

    Highlights: {yields} Tc sorption on alumina has been studied under aerobic as well anaerobic condition over pH 3-10. {yields} Effect of humic acid on sorption of Tc by alumina has been investigated. {yields} Linear additive modeling and surface complexation modeling were carried out to delineate the role of humic acid in Tc(IV) sorption in ternary system of Tc(IV)-humic acid-alumina. {yields} Sorption of humic acid onto alumina and strong complexation of Tc(IV) with humic acid were found to govern the sorption of Tc(IV) in the ternary system. - Abstract: Sorption of technetium by alumina has been studied in absence as well as in presence of humic acid using {sup 95}Tc{sup m} as a tracer. Measurements were carried out at fixed ionic strength (0.1 M NaClO{sub 4}) under varying pH (3-10) as well as redox (aerobic and reducing anaerobic) conditions. Under aerobic conditions, negligible sorption of technetium was observed onto alumina both in absence and in presence of humic acid. However, under reducing conditions (simulated with [Sn(II)] = 10{sup -6} M), presence of humic acid enhanced the sorption of technetium in the low pH region significantly and decreased at higher pH with respect to that in absence of humic acid. Linear additive as well as surface complexation modeling of Tc(IV) sorption in presence of humic acid indicated the predominant role of sorbed humic acid in deciding technetium sorption onto alumina.

  8. Sorption of curium by silica colloids: Effect of humic acid

    Energy Technology Data Exchange (ETDEWEB)

    Kar, Aishwarya Soumitra; Kumar, Sumit [Radiochemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Tomar, B.S., E-mail: bstomar@barc.gov.in [Radiochemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Manchanda, V.K. [Radiochemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India)

    2011-02-28

    Sorption of curium by silica colloids has been studied as a function of pH and ionic strength using {sup 244}Cm as a tracer. The sorption was found to increase with increasing pH and reach a saturation value of {approx}95% at pH beyond 5.3. The effect of humic acid on the sorption of {sup 244}Cm onto silica was studied by changing the order of addition of the metal ion and humic acid. In general, in the presence of humic acid (2 mg/L), the sorption increased at lower pH (<5) while it decreased in the pH range 6.5-8 and above pH 8, the sorption was found to increase again. As curium forms strong complex with humic acid, its presence results in the enhancement of curium sorption at lower pH. At higher pH the humic acid present in the solution competes with the surface sites for curium thus decreasing the sorption. The decrease in the Cm sorption in presence of humic acid was found to be less when humic acid was added after the addition of curium. Linear additive model qualitatively reproduced the profile of the Cm(III) sorption by silica in presence of humic acid at least in the lower pH region, however it failed to yield quantitative agreement with the experimental results. The results of the present study evidenced the incorporation of Cm into the silica matrix.

  9. Replenishing Humic Acids in Agricultural Soils

    Directory of Open Access Journals (Sweden)

    Michael Susic

    2016-09-01

    Full Text Available For many decades, it was commonly believed that humic acids were formed in soils by the microbial conversion of plant lignins. However, an experiment to test whether these humic acids were formed prior to plant matter reaching the soil was never reported until the late 1980s (and then only as a side issue, even though humic acids were first isolated and reported in 1786. This was a serious omission, and led to a poor understanding of how the humic acid content of soils could be maintained or increased for optimum fertility. In this study, commercial sugar cane mulch and kelp extracts were extracted with alkali and analyzed for humic acid content. Humic acids in the extracts were positively identified by fluorescence spectrophotometry, and this demonstrated that humic acids are formed in senescent plant and algal matter before they reach the soil, where they are then strongly bound to the soil and are also resistant to microbial metabolism. Humic acids are removed from soils by wind and water erosion, and by water leaching, which means that they must be regularly replenished. This study shows that soils can be replenished or fortified with humic acids simply by recycling plant and algal matter, or by adding outside sources of decomposed plant or algal matter such as composts, mulch, peat, and lignite coals.

  10. Iodine binding to humic acid

    OpenAIRE

    Bowley, Hannah E.; Young, Scott D.; Ander, E. Louise; Crout, Neil J.M.; Crout, N.M.J.; Watts, Michael J.; Bailey, Elizabeth H.

    2016-01-01

    The rate of reactions between humic acid (HA) and iodide (I-) and iodate (IO3-) have been investigated in suspensions spiked with 129I at concentrations of 22, 44 and 88 µg L-1 and stored at 10oC. Changes in the speciation of 129I-, 129IO3- and mixed (129I-+129IO3-) spikes were monitored over 77 days using liquid chromatography inductively coupled plasma mass spectrometry (LC-ICP-MS). In suspensions spiked with 129I- 25% of the added I- was transformed into organic iodine (Org-129I) within...

  11. Humic acid enhances cigarette smoke-induced lung emphysema in mice and IL-8 release of human monocytes

    NARCIS (Netherlands)

    Eijl, S. van; Mortaz, E.; Ferreira, A.F.; Kuper, F.; Nijkamp, F.P.; Folkerts, G.; Bloksma, N.

    2011-01-01

    Tobacco smoke is the main factor in the etiology of lung emphysema. Generally prolonged, substantial exposure is required to develop the disease. Humic acid is a major component of cigarette smoke that accumulates in smokers' lungs over time and induces tissue damage. Objectives: To investigate

  12. Chemical immobilisation of humic acid on silica

    NARCIS (Netherlands)

    Koopal, L.K.; Yang, Y.; Minnaard, A.J.; Theunissen, P.L.M.; Riemsdijk, W.H. van

    1998-01-01

    Immobilisation of purified Aldrich humic acid (PAHA) on aminopropyl silica and glutaraldehyde-activated aminopropyl silica has been investigated. In general the humic acid is bound to the solid by both physical and chemical bonds. The physically adsorbed HA can be released to a large extent at high

  13. Buffer capacity of humic acid: thermodynamic approach.

    Science.gov (United States)

    Pertusatti, Jonas; Prado, Alexandre G S

    2007-10-15

    Commercial humic acid was dialyzed and characterized by infrared, UV/vis spectroscopy, (13)C NMR spectrometry, thermogravimetry, and elemental analysis. The dialyzed humic acid was titrated with HNO(3) and NaOH in order to obtain the buffer capacity value (beta). The humic acid presented buffer behavior by base and acid addition, and moreover, an excellent buffer capacity by addition of NaOH. Humic acid showed buffer action between pH 5.5 and 8.0, and a maximum buffer capacity at pH 6.0. The same study was followed calorimetrically to determinate the enthalpy of interaction between H(+)/OH(-) and buffer, which resulted in a maximum enthalpy of -38.49 kJ mol(-1) at pH 6.0. This value suggests that the buffer activity is based on chemisorption of proton and hydroxyl.

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

    African Journals Online (AJOL)

    Jane

    2011-06-22

    Jun 22, 2011 ... metabolism are less understood, but it seems that humic substances may influence both respiration and photosynthesis (Nardi et al., 2002). Humic substances have a very strong influence on the growth of plant roots. When humic and fulvic acids are applied on the soil, enhancement of root initiation and.

  15. 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...

  16. Photocatalytic Degradation of Humic Acid by Fe-TiO2 Supported on Spherical Activated Carbon with Enhanced Activity

    Directory of Open Access Journals (Sweden)

    Mi-Hwa Baek

    2013-01-01

    Full Text Available Fe-TiO2 supported on spherical activated carbon (Fe-TiO2/SAC with different Fe contents was prepared by heat treatment process after ion exchange method. The prepared Fe-TiO2/SAC was characterized by SEM, EDS, and BET. Batch experiments for photocatalytic degradation of humic acid by Fe-TiO2/SAC were carried out in the fluidized bed photoreactor. It was found that 0 wt% Fe-TiO2/SAC had high photocatalytic activity in the wavelength range of 100~280 nm. However, Fe-TiO2/SAC with Fe contents of 0.4, 0.6, and 0.8 wt% exhibited higher photocatalytic activity than 0 wt% Fe-TiO2/SAC in the wavelength range of 315~400 nm compared to that of 100~280 nm. The optimum Fe content was 0.6 wt% for maximum photocatalytic degradation of humic acid. Moreover, Fe-TiO2/SAC does not require an additional process step for separation of photocatalyst from treated water after photocatalysis.

  17. 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.

  18. 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...

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

    African Journals Online (AJOL)

    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 reesei) species using empty ...

  20. Spectral Study of Modified Humic Acids from Lignite

    Science.gov (United States)

    Zherebtsov, Sergey; Malyshenko, Natalya; Bryukhovetskaya, Ludmila; Ismagilov, Zinfer

    2017-11-01

    The IR-Fourier, ESR and solid-state 13C NMR analysis are used for investigation of unmodified and modified humic acids obtained from Tisul lignite (the Kansko-Achinsk Basin). Treatment with Hydrogen peroxide used for modification of humic acids and it changes the functionalgroup composition of the humic acids and increases the sorptional capacity

  1. Copper binding to soil fulvic and humic acids

    NARCIS (Netherlands)

    Xu, Jinling; Tan, Wenfeng; Xiong, Juan; Wang, Mingxia; Fang, Linchuan; Koopal, Luuk K.

    2016-01-01

    Binding of Cu(II) to soil fulvic acid (JGFA), soil humic acids (JGHA, JLHA), and lignite-based humic acid (PAHA) was investigated through NICA-Donnan modeling and conditional affinity spectrum (CAS). It is to extend the knowledge of copper binding by soil humic substances (HS) both in respect of

  2. Effect of humic acid source on humic acid adsorption onto titanium dioxide nanoparticles.

    Science.gov (United States)

    Erhayem, Mohamed; Sohn, Mary

    2014-02-01

    In many studies, different humic acid (HA) sources are used interchangeably to evaluate the effect of organic matter on geochemical processes in the environment. This research looks more specifically at the effect of HA source on HA adsorption onto nano-TiO2 and how HA adsorption affects the fate and transport of nano-TiO2. In this study, six humic acids (HAs) were studied which were derived from soils (SLHA), or from sediments (SDHA) all originating from the state of Florida. Humic acid adsorption onto titanium dioxide nanoparticles (nano-TiO2) and the sedimentation of HA-coated and uncoated nano-TiO2 were monitored by Ultraviolet-visible (UV-vis) spectroscopy. Synchronous scan fluorescence (SSF) spectroscopy was used to complement the study of HA adsorption onto nano-TiO2. Phosphate buffer was found to reduce the amount of HA adsorbed onto nano-TiO2 relative to solutions of NaCl of the same pH and ionic strength. Adsorption constant values (Kads) for HAs varied in the order SLHA>FSDHA (freshwater sedimentary HA)>ESDHA (estuarine sedimentary HA). SSF results suggested that the more highly conjugated fractions of HA, which are more prevalent in SLHAs versus SDHAs, were preferentially adsorbed. In order to better understand the relationship between adsorption and aggregation, sedimentation studies were conducted and it was found that the percentage of nano-TiO2 sedimentation was preferentially enhanced in the order of the presence of SLHA>FSDHA>ESDHA. The extent of nano-TiO2 sedimentation was decreased with increasing HA concentration. TEM imaging of nano-TiO2 confirmed that nano-TiO2 was aggregated in the presence of HAs. The findings in this study suggest that HAs from different sources influence the fate and transport of nano-TiO2 in the environment differently. © 2013.

  3. Chemical and spectroscopic characteristics of humic acids

    NARCIS (Netherlands)

    Ferreira, F.; Vidal-Torrado, P.; Otero, X.L.; Buurman, P.

    2013-01-01

    To characterise soil humic acids (HAs) extracted from Spanish marshes formed under different vegetation types (Spartina maritima (GSp), Juncus maritimus (GJc), Phragmites australis (GPh), and Scirpus maritimus (VSc)), soil depths (0-20, 20-40 and 40-60 cm), physiographic position (low and high

  4. 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...

  5. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Hu Miao [School of Resources Environment, Northeast Agricultural University, Harbin 150030 (China); Zhang Ying, E-mail: zhangyinghr@hotmail.com [School of Resources Environment, Northeast Agricultural University, Harbin 150030 (China); Wang Zhigang; Jiang Zhao; Li Juan [School of Resources Environment, Northeast Agricultural University, Harbin 150030 (China)

    2011-06-15

    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.

  7. Interaction of Humic Acids with Organic Toxicants

    Science.gov (United States)

    Tchaikovskaya, O. N.; Yudina, N. V.; Maltseva, E. V.; Nechaev, L. V.; Svetlichnyi, V. A.

    2016-08-01

    Interaction of humic acids with polyaromatic hydrocarbons (PAH) (naphthalene and anthracene) and triazole series fungicides (cyproconazole (CC) and tebuconazole (TC)) is investigated by the method of fluorescence quenching depending on the concentration of substances in solutions and their structural features. Humic acids were modified by mechanochemical activation in a planetary mill. The complex character of intermolecular interactions between PAH and fungicides with humic acids, including donor-acceptor and hydrophobic binding, is established. Thermodynamically stable conformations of biocide molecules were estimated using ChemOffice CS Chem3D 8.0 by methods of molecular mechanics (MM2) and molecular dynamics. Biocide molecules with pH 7 are in energetically favorable position when the benzene and triazole rings are almost parallel to each other. After acidification of solutions to pH 4.5, the CC molecule retains the geometry for which donor-acceptor interactions are possible: the benzene ring in the molecule represents the electron donor, and triazole is the acceptor. In this case, the electron density in CC is redistributed easier, which is explained by a smaller number of carbon atoms between the triazole and benzene rings, unlike TC. As a result, the TC triazole ring is protonated to a greater degree, acquiring a positive charge, and enters into donoracceptor interactions with humic acid (HA) samples. The above-indicated bond types allow HA to participate actively in sorption processes and to provide their interaction with biocides and PAH and hence, to act as detoxifying agents for recultivation of the polluted environment.

  8. Metalion-humic acid nanoparticle interactions

    OpenAIRE

    Town, Raewyn M.; Leeuwen, van, M.G.A.

    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 anomalously high Donnan potentials, as well as intrinsic affinity constants for electrostatically associating ions such as Ca2+. In contrast, the recently introduced counterion condensation-Donnan mo...

  9. Copper(II and lead(II complexation by humic acid and humic-like ligands

    Directory of Open Access Journals (Sweden)

    IVANA KOSTIĆ

    2011-09-01

    Full Text Available The stability of metal–humate complexes is an important factor determining and predicting speciation, mobility and bioavailability of heavy metals in the environment. A comparative investigation of the complexation of Cu(II and Pb(II with humic acid and humic-like ligands, such as benzoic and salicylic acid, was performed. The analysis was realized at pH 4.0, a temperature of 25 °C and at an ionic strength of 0.01 mol dm-3 (NaCl using the Schubert ion-exchange method and its modified form. The stability constants were calculated from the experimental data by the Schubert method for complexes with benzoic and humic acid. A modified Schubert method was used for the determination of the stability constants of the complexes with salicylic acid. It was found that Cu(II and Pb(II form mononuclear complexes with benzoic and humic acid while with salicylic acid both metals form polynuclear complexes. The results indicate that Pb(II has a higher binding ability than Cu(II to all the investigated ligands. The Cu(II–salicylate and Pb(II–salicylate complexes showed noticeable higher stability constants compared with their complexes with humic acid, while the stabilities of the complexes with benzoic acid differed less. Salicylic and benzoic acids as humic-like ligands can be used for setting the range of stability constants of humic complexes with Cu(II and Pb(II.

  10. Rare earth elements complexation with humic acid

    OpenAIRE

    Pourret, Olivier; Davranche, Mélanie; Gruau, Gérard; Dia, Aline

    2007-01-01

    The binding of rare earth elements (REE) to humic acid (HA) was studied by combining ultrafiltration and Inductively Coupled Plasma Mass Spectrometry techniques. REE­HA complexation experiments were performed at various pH conditions (ranging from 2 to 10.5) using a standard batch equilibration method. Results show that the amount of REE bound to HA strongly increases with increasing pH. Moreover, a Middle-REE (MREE) downward concavity is evidenced by REE distribution patterns at acidic pH. M...

  11. Lability of copper bound to humic acid

    OpenAIRE

    Mao, Lingchen; Young, Scott D.; Bailey, Liz

    2015-01-01

    Geochemical speciation models generally include the assumption that all metal bound to humic acid and fulvic acid (HA, FA) is labile. However, in the current study, we determined the presence of a soluble ‘non-labile’ Cu fraction bound to HA extracted from grassland and peat soils. This was quantified by determining isotopically-exchangeable Cu (E-value) and EDTA-extraction of HA-bound Cu, separated by size-exclusion chromatography (SEC) and assayed by coupled ICP-MS. Evidence of time-depend...

  12. 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.

  13. Isolation and characterization of aquatic humic acid and fulvic acid

    Energy Technology Data Exchange (ETDEWEB)

    Rhee, D.S. [Kangwon National University, Chunchon (Korea)

    2002-02-01

    The dissolved organic carbon extracted from groundwater is separated into humic acid and fulvic acid. They are characterized for their chemical composition, spectroscopic characteristics using UV/VIS, IR and solid state {sup 13}C-NMR spectroscopy, proton exchange capacity and molecular size distribution. The results are comparable with the literature data. The study explains that the aquatic humic and fulvic acid in this experiment are site-specipic and polydisperse natural organic matter with considerable proton exchange capacity. (author). 16 refs., 5 tabs., 4 figs.

  14. Trace metals in humic acids and their hydrolysis products

    Energy Technology Data Exchange (ETDEWEB)

    Huljev, D.J.

    1986-04-01

    The role of humic acids in the transport of trace elements in the Sava river biocycle (near Zagreb, Yugoslavia) has been investigated by means of neutron activation analysis. Humic acids can accumulate certain trace elements, but little is known about their selectivity under certain physicochemical conditions. Humic acids isolated from Sava river sediments were hydrolized to their main components, namely to amino acids (proteins), phenols (and phenolic acids), carbohydrates, polycyclic aromatics, and metals. Degradation of humic acids in the environment occurs by the action of microorganisms, and during this step, certain trace metals become available to Sava river animals through standard physiological processes. In this work neutron activation analysis was applied to the quantitative and qualitative determination of trace metals in humic acids of Sava river origin, and in their hydrolysis products. The trace metals measured were Ag, Fe, Co, Cs, Eu, Sb, Sc, Se, and Sr. The concentrations obtained ranged from 0.05 to 2730 ..mu..g of a certain microconstituent per gram of sample. The experimental data are compared with laboratory experiments on the determination of stability constants for metal complexes of humic acids and their hydrolysis product. From these data it is possible to suggest the ecological importance of trace metals bonded to humic acids in a certain region. The results concerning the role of humic acids in the cycle of trace elements in Sava river biocycle are discussed.

  15. MODELING LANTHANIDE BINDING SITES ON HUMIC ACID

    OpenAIRE

    Pourret, Olivier; Martinez, Raul,

    2009-01-01

    International audience; Lanthanide (Ln) binding to humic acid (HA) has been investigated by combining ultrafiltration and ICP-MS techniques. A Langmuir sorption isotherm metal complexation model was used in conjunction with a linear programming method (LPM) to fit experimental data representing a wide range of experimental conditions both in HA/Ln ratio (varying between 5 and 20) and in pH range (from 2 to 10) with a ionic strength of 10-3 mol L-1. The LPM approach, not requiring prior knowle...

  16. 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.

    effects of humic and fulvic acids on the DGT detection of metal species have been observed, the gel permeation properties of the actual humic and fulvic acid compounds themselves have not been analyzed thus far. Here we show with DET (Diffusive Equilibrium...

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

    African Journals Online (AJOL)

    ABSTRACT. Experiments were carried out to study humic acid solutions and surface waters coagulation by Moringa oleifera Lam seeds aqueous extract. High amounts of such extract (up to. 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.

  18. 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 ...

  19. Interaction of metals with humic acid isolated from oxidized coal

    Energy Technology Data Exchange (ETDEWEB)

    Erdogan, S.; Baysal, A.; Akba, O.; Hamamci, C. [Dicle University, Diyarbakir (Turkey)

    2007-07-01

    The sorption behaviour of divalent cations M{sup 2+} (Cu, Pb and Zn) and trivalent cations M{sup 2+} (Fe, Al) with humic acid isolated from oxidized coal (Hazro, SE Anatolia,Turkey) was followed in aqueous solution. Coal humic acid and metal ion interaction was investigated with special emphasis on the effects of pH, metal ion concentration and humic acid concentration. It has been found that the interaction of humic acid with metal ions in solution increases with pH, decreases with metal ion concentration and increases with humic acid concentration. The differences in sorption ability of particular metal ions on oxidized coal-derived humic acid are Fe> Pb> Cu> Al> Zn and Fe> Pb> Al> Cu> Zn at pH 2.5 and 3.5, respectively, while they are Fe=Pb=Cu=Al> Zn at both pH 4.5 and 5.5. The interaction of some trivalent (Fe, Al) and divalent (Cu, Pb, Zn) metal ions with humic acid prepared from coal was also studied using FTIR spectroscopy. This has proven helpful with respect to metal binding to understand better the potential sites of binding within the humic acid. Infrared spectroscopy showed the participation of COOH and OH groups in binding to the metal ions.

  20. 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

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

    African Journals Online (AJOL)

    ONOS

    2010-09-06

    Sep 6, 2010 ... Humic acids may stimulate shoot and root growth, and improve resistance to environmental stress in plant, but the physiological mechanism has not been well established (Delfine et al., 2005). Türkmen et al. (2005) suggested that humic acid may promote much growth of pepper seedlings in salty condition.

  2. Studies of metal complexation with humic and fulvic acid

    Energy Technology Data Exchange (ETDEWEB)

    King, S.J.; Warwick, P. [Loughborough Univ. (United Kingdom). Dept. of Chemistry

    1998-08-01

    The main objective of the project is to determine the influence of humic substances on the migration of radionuclides. One of the first steps taken in order to deepen this understanding was to investigate the complexation of Eu{sup 3+} with humic substances (Task 2). There is concern that after disposal in underground repositories radionuclides may eventually come into contact with groundwaters containing humic acids at elevated temperatures. Preliminary investigations have therefore been undertaken to determine the effect of temperature on the stability constants for europium binding to humic acid by a series of batch experiments. Eu is used as an analogue of trivalent actinides. (orig.)

  3. 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...... shows tree characteristic regions with markedly different precipitation courses: region I at HA concentration below 0.15g/l, region H at HA concentration between 0.15 and similar to2g/l and rgeion IV at HA concentration above 3.5g/l. Furthermore, a forth intermediate region M is observed between similar...... to2 and 3.5g/l. In order to understand these measurements and precipitation behaviour a phase diagram model is constructed using a simple thermodynamic approach. The result of this analysis shows that precipitation in region I and U can be explained by a simple equilibrium reaction between the HA...

  4. 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.

  5. 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.

  6. Np(V) reduction by humic acid: Contribution of reduced sulfur functionalities to the redox behavior of humic acid

    Energy Technology Data Exchange (ETDEWEB)

    Schmeide, K., E-mail: k.schmeide@hzdr.de; Sachs, S.; Bernhard, G.

    2012-03-01

    The role of sulfur-containing functional groups in humic acids for the Np(V) reduction in aqueous solution has been studied with the objective to specify individual processes contributing to the overall redox activity of humic substances. For this, humic acid model substances type M1-S containing different amounts of sulfur (1.9, 3.9, 6.9 wt.%) were applied. The sulfur functionalities in these humic acids are dominated by reduced-sulfur species, such as thiols, dialkylsulfides and/or disulfides. The Np(V) reduction behavior of these humic acids has been studied in comparison to that of the sulfur-free humic acid type M1 at pH 5.0, 7.0 and 9.0 under anaerobic conditions by means of batch experiments. For Np redox speciation in solution, solvent extraction and ultrafiltration were applied. In addition, redox potentials of the sample solutions were monitored. At pH 5.0, both rate and extent of Np(V) to Np(IV) reduction were found to increase with increasing sulfur content of the humic acids. At pH 7.0 and 9.0, sulfur functional groups had only a slight influence on the reduction behavior of humic acid toward Np(V). Thus, in addition to quinoid moieties and non-quinoid phenolic OH groups, generally acknowledged as main redox-active sites in humic substances, sulfur functional groups have been identified as further redox-active moieties of humic substances being active especially in the slightly acidic pH range as shown for Np(V). Due to the low sulfur content of up to 2 wt.% in natural humic substances, their contribution to the total reducing capacity is smaller than that of the other redox-active functional groups. - Highlights: Black-Right-Pointing-Pointer Redox processes of humic substances control the speciation and mobility of metal ions in the environment. Black-Right-Pointing-Pointer Sulfur functional groups were identified as further redox-active sites in humic substances toward Np(V). Black-Right-Pointing-Pointer The specification of processes contributing to

  7. 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...

  8. Growth respone, production and quality of grass resulted from addition of arbuscular mycorrhizal fungi and humic acid on acid soil with high aluminium content

    Directory of Open Access Journals (Sweden)

    Panca Dewi Manu Hara Karti

    2011-06-01

    Full Text Available Arbuscular mycorrhizal fungi (AMF can help plant to uptake of low P availability in acid soils because of the ability of AMF to adapt from acid soil. Humic acid plays a role in adsorption metals such as Al. The purpose of this research was to study the effect of addition of AMF and humic acid to acid soils on growth, yield and quality of grass. A complete randomized design with factorial pattern was applied to two types of grasses, namely: Setaria splendida (Al-tolerance and Chloris gayana (Al-sensitive. The first factor is the addition of AMF, which consists of two levels, namely: -AMF = without AMF. +AMF = with AMF. The second factor was the addition of humic acid which consists of four levels, namely: Ho = without humic acid, H60 = 60 ppm humic acid usage, H120 = 120 ppm humic acid usage and H180 = 180 ppm humic acid usage. Variables measured were dry matter production of shoot and roots, uptake of P and N, the production of phosphatase, root infection, the number of spores. AMF and humic acid augmentation on Setaria splendida did not affect on growth and production, but they improved the uptake of P and N total. AMF augmentation enhanced growth, yield and quality of the Chloris gayana. The use of 180 ppm of humic acid could improve the quality of Setaria splendida and Chloris gayana.

  9. Clarithromycin and tetracycline binding to soil humic acid in the absence and presence of calcium

    Science.gov (United States)

    Christl, Iso; Ruiz, Mercedes; Schmidt, J. R.; Pedersen, Joel A.

    2017-04-01

    Many organic micropollutants including antibiotics contain positively charged moieties and are present as organic cations or zwitterions at environmentally relevant pH conditions. In this study, we investigated the pH-, ionic strength-, and concentration-dependent binding of the two antibiotics clarithromycin and tetracycline to dissolved humic acid in the absence and presence of Ca2+. The investigated compounds strongly differ in their chemical speciation. Clarithromycin can be present as neutral and cationic species, only. But tetracycline can form cations, zwitterions as well as anions and is able to form various calcium complexes. The pH-dependence of binding to soil humic acid was observed to be strongly linked to the protonation behavior for both antibiotics. The presence of Ca2+ decreased clarithromycin binding to soil humic acid, but increased tetracycline binding with increasing Ca2+ concentration. The experimental observations were well described with the NICA-Donnan model considering the complete aqueous speciation of antibiotics and allowing for binding of cationic and zwitterionic species to soil humic acid. Our results indicate that clarithromycin is subject to competition with Ca2+ for binding to soil humic acid and that the electrostatic interaction of positively charged tetracycline-Ca complexes with humic acid enhances tetracycline binding in presence of Ca2+ rather than the formation of ternary complexes, except at very low tetracycline concentrations. We conclude that for the description of ionizable organic micropollutant binding to dissolved natural organic matter, the complete speciation of both sorbate and sorbent has to be considered.

  10. Dechlorination of tetrachloroethylene by palladized iron in the presence of humic acid.

    Science.gov (United States)

    Doong, Ruey-An; Lai, Yen-Jung

    2005-06-01

    The dechlorination of tetrachloroethylene (PCE) by palladized irons in the presence of humic acid was investigated to understand the feasibility of using Pd/Fe for the in situ remediation of contaminated groundwater. Untreated zerovalent iron (ZVI) was amended with Pd(II) ions to form palladized irons. X-ray photoelectron spectroscopy showed that Pd(II) was completely reduced to metallic Pd on the surface of ZVI. PCE was catalytically dechlorinated via beta-elimination to ethane and ethylene by palladized irons. The carbon mass balances were in the range of 78--98%. The dechlorination followed the pseudo first-order rate equation and the normalized surface reaction rate constant (k(sa)) for PCE dechlorination was 33.47+/-7.21 L/m(2)h in the absence of humic acid. Humic acid competed the reactive sites on the palladized irons with PCE, and thus lowered the dechlorination efficiency and rate of PCE. After 24h of equilibrium between humic acid and palladized irons prior to the injection of PCE, however, the efficiency and rate of PCE dechlorination could increase with increasing concentrations of humic acid. Addition of quinones having low redox potentials including AQDS, lawsone and hydroquinone also enhanced the dechlorination efficiency of PCE after 24h, depicting that humic acids serve as the electron shuttles to effectively transfer electrons and to accelerate the dechlorination efficiency and rate of PCE.

  11. Micro-organization of humic acids in aqueous solutions

    Science.gov (United States)

    Klučáková, Martina; Věžníková, Kateřina

    2017-09-01

    The methods of dynamic light scattering and micro-rheology were used to investigate the molecular organization of humic acids in solutions. The obtained results were supplemented by ultraviolet/visible spectrometry and measurement of the zeta potential. Particle tracking micro-rheology was used for the first time as a novel method in humic research. Solutions of humic acids were prepared in three different mediums: NaOH, NaCl, and NaOH neutralized by HCl after dissolution of the humic sample. The molecular organization of humic acids was studied over a wide concentration range (0.01-10 g dm-3). Two breaks were detected in the obtained concentration dependencies. The rearrangements were observed at concentrations around 0.02 g dm-3 and 1 g dm-3. Changes in the measured values observed at around 0.02 g dm-3 were less noticeable and were related to the formation of particles between 100 and 1000 nm in size and the strong bimodal character of humic systems diluted by NaCl. The ;switch-over point; at around 1 g dm-3 indicated changes in the secondary structure of humic acids connected with the increase in colloidal stability (decrease of zeta potential), the decrease in polydispersity, and minimal values of viscosity.

  12. Luminescence from {gamma}-irradiated humic acid

    Energy Technology Data Exchange (ETDEWEB)

    Goraczko, Wieslaw [Faculty of Chemical Technology, Radio- and Photochemistry Department, Poznan University of Technology, ul. Piotrowo 3, 60-965 Poznan (Poland)], E-mail: wieslaw.goraczko@put.poznan.pl; Slawinski, Janusz [Institute of Ecotechnology, State Higher Vocational School, ul. Ks. Kard. S.Wyszynskiego 38, 62-200 Gniezno (Poland)

    2008-07-15

    This study was conducted to investigate the ultraweak delayed radiochemiluminescence (RCL) spectra, kinetics and spectroscopic properties of humic acids (HAs) after {gamma}-radiation exposure (absorbed doses of 1-10 kGy, Co-60) in model systems. The kinetics and spectral distribution of RCL (340-650 nm) were measured using the single photon counting (SPC) method and cut-off filters. The intensity of fluorescence ({lambda}{sub ex}=390, 440, 490 and 540 nm) covering the spectral range 400-580 nm was heavily dependent on the {lambda}{sub ex} and slightly increased with the absorbed dose of {gamma}-radiation. Absorption spectra (the range 240-800 nm) and color coefficients E{sub 2.6/4} and E{sub 4/6} of irradiated solutions indicated that post-radiative degradation/polymerization processes take place in the HA, changing their macromolecule size or properties. Comparison of FTIR spectra and elemental analysis proved an increased O and decreased C atoms in irradiated samples. The data indicate on the radiolysis-induced degradation of native HA into fulvic-like acids with higher hydrophilicity and lower molecular size.

  13. 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

  14. REDUCTION AND OXIDATION PROCESSES OF CHROMIUM IN HUMIC ACID SUBFRACTION-SENSITIZED PHOTOCATALYST

    Directory of Open Access Journals (Sweden)

    Uripto Trisno Santoso

    2010-06-01

    Full Text Available The process of reduction and oxidation of soluble chromium in humic acid subfraction-sensitized photocatalyst was studied. Humic acid was extracted from peat soil sampled in Gambut District, South Kalimantan. Humic acid (HA was fractionated to humic acid subfraction (HAS by centrifugation method. ZnO and TiO2 were applied as the photocatalysts produced by Merck, suspended in solution of 2 g/L. Two germicide UV lamps 30 watt (Philip® was placed in a box at 20 cm above the samples. The results showed that HA or HAS sensitized the photoreduction of Cr(VI by photocatalyst. The low molecular weight of HAS is more effective to act as sensitizer than the high molecular weight one. The yield of the photoreduction of Cr(VI with photocatalysts enhanced both in the presence of Fe(II ion and HAS. UV irradiation of the MnO4- solutions containing Cr(III induced the photooxidation of Cr(III to Cr(VI. The presence of Fe(III or HAS doesn't inhibit significantly. The inhibition is enhanced by the present of both HAS and Fe(II or HAS and Fe(III. This inhibition is enhanced more by the presence of ZnO or TiO2 photocalysts.   Keywords: reduction, oxidation, chromium, humic acid, photocatalyst

  15. Copper(II) and lead(II) complexation by humic acid and humic-like ligands

    OpenAIRE

    IVANA KOSTIĆ; TATJANA ANĐELKOVIĆ; RUŽICA NIKOLIĆ; ALEKSANDAR BOJIĆ; MILOVAN PURENOVIĆ; SRĐAN BLAGOJEVIĆ; DARKO ANĐELKOVIĆ

    2011-01-01

    The stability of metal–humate complexes is an important factor determining and predicting speciation, mobility and bioavailability of heavy metals in the environment. A comparative investigation of the complexation of Cu(II) and Pb(II) with humic acid and humic-like ligands, such as benzoic and salicylic acid, was performed. The analysis was realized at pH 4.0, a temperature of 25 °C and at an ionic strength of 0.01 mol dm-3 (NaCl) using the Schubert ion-exchange method and its modified form....

  16. 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.

  17. Ozonization of polyfunctional and humic acids of sapropelites

    Energy Technology Data Exchange (ETDEWEB)

    Verkhodanova, N.N.; Myakina, I.A.; Egor' kov, A.N.; Shiskov, V.F.; Tuturina, V.V.

    1981-01-01

    Data are presented which show that in the ozonization of polyfunctional acids (PFAs) and humic acids (HAs) in glacial acetic acid, all the organic carbon can be converted into the soluble form. Mono- and dicarboxylic acids of normal structure have been detected in the ozonization products. 5 refs.

  18. Characteristics of unburned carbons and their application for humic acid removal from water

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Shaobin [Department of Chemical Engineering, Curtin University of Technology, G.P.O. Box U1987, Perth, WA 6845 (Australia); Ma, Qing; Zhu, Z.H. [ARC Centre of Excellence for Functional Nanomaterials and Division of Chemical Engineering, The University of Queensland, St. Lucia, QLD 4072 (Australia)

    2009-03-15

    Two unburned carbons (UCs) were separated from coal fly ash and their physicochemical properties were characterised using N{sub 2} adsorption, XRD, SEM, XPS, FT-IR and potentiometric mass titration. Chemical treatments using HNO{sub 3} and KOH were also conducted on one of the unburned carbons. The adsorption of humic acid from aqueous solution was performed on these untreated and chemically treated UCs. It was found that the UCs showed different porous structure and surface chemical properties, which influenced their adsorption behaviour. UCs exhibited high adsorption capacity for humic acid. After chemical treatment, the textural structure and surface functional groups of the unburned carbon were changed and the adsorption behaviour showed significant difference. Acid treatment did not change the surface area but reduced the functional groups while basic treatment significantly enhanced the surface area in microporous section but still reduced the surface functional groups. Particle size and pH solution will also influence the adsorption capacity. The adsorption will increase with decreasing particle size for humic acid. Higher pH solution will reduce humic acid adsorption on unburned carbon. Ionic strength will also affect humic acid adsorption showing positive effect on adsorption capacity. (author)

  19. 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).

  20. The Effect of Humic Acid on Nutrient Composition in Broad Bean (Vicia faba L. Roots

    Directory of Open Access Journals (Sweden)

    Sener AKINCI

    2009-12-01

    Full Text Available Humic acids promote the conversion of mineral nutrients into forms available to plants. It also stimulates seed germination and viability, and its main effect usually being more prominent in the roots. The objective of this study was to determine of the influence of humic acid on broad bean (Vicia faba L. cultivar �Eresen 87� on root growth and development as well as nutrient uptake, during investigation in a pot experiment. Treatment with leonardite, as humic acid source positively affected both germination and harvesting, enhancing root length and biomass. Humic acid (HA caused significant increase of fresh (RFW and dry (RDW weights by 30.1% and 56.6% of broad bean roots, respectively. Flame photometer and atomic absorption spectrophotometry analyses revealed that K content was major nutrient among the tested elements. Humic acid increased the contents of Na and K significantly. The content of Ca and Fe was not significantly increased whereas Cu, Mn and Zn content decreased under HA treatment.

  1. Kinetic study for copper adsorption onto soil minerals in the absence and presence of humic acid.

    Science.gov (United States)

    Komy, Zanaty R; Shaker, Ali M; Heggy, Said E M; El-Sayed, Mohamed E A

    2014-03-01

    Equilibrium and kinetics of Cu(2+) adsorption onto soil minerals (kaolinite and hematite) in the absence and presence of humic acid have been investigated under various conditions. The influences of ionic strength, pH and solution cations on the rate of the adsorption have been studied. The rate and the amount of adsorbed Cu(2+) onto soil minerals in the absence or the presence of humic acid increased with decreasing ionic strength, increasing pH and in the presence of the background electrolyte K(+) rather than Ca(2+). Humic acid enhanced the rate and the amount of adsorbed Cu(2+) onto soil minerals. The adsorption equilibrium data showed that adsorption behavior of Cu(2+) could be described more reasonably by Langmiur adsorption isotherm than Freundlich isotherm in the absence or presence of humic acid. Pseudo first and pseudo second order models were used to evaluate the kinetic data and the rate constants. The results indicated that the adsorption of Cu(2+) onto hematite and kaolinite in the absence and presence of humic acid is more conforming to pseudo second order kinetics. Copyright © 2013 Elsevier Ltd. All rights reserved.

  2. [Adsorption characteristics and mechanism of atrazine on three types of humic acid].

    Science.gov (United States)

    Chang, Chun-ying; Zheng, Yin-tian; Lü, Yi-zhong

    2010-10-01

    This study mainly researched the adsorption properties and adsorption mechanism of atrazine on three different types of humic acids: the black soil humic acid, the chestnut soil humic acid and the humic acid purchased. After the extraction of humic acid from the two different types of soil, the black soil and chestnut soil, adsorption experiments were carried out using the batch equilibrium techniques. Then FTIR and ESR spectral analysis methods were employed to explain the functional mechanism between atrazine and humic acid. The results showed that the sorption of humic acid on atazine was very fast at the beginning, then went to slower and finally came to equilibrium. The relationship between the amount of atrazine sorbed by the three humic acids and reaction time all fitted logarithmic and hyperbolic equations well. Adsorption isotherms of atrazine on the three humic acids all are L-type and in accordance with the linear model and the Freundlich model. Because of the different structure, there is significant difference between the adsorption isotherm of atrazine on purchased humic acid and extract humic acid. The interactions between humic acid and atrazine are mostly weak forces, such as the H-bond, proton transfer, charge transfer, van der Waals force and so on. In addition, ESR analysis proved that charge transfer exists between humic acid and atrazine during the process of adsorption.

  3. HUMIC ACID ON GERMINATION AND VIGOR OF CORN SEEDS

    Directory of Open Access Journals (Sweden)

    LENNIS AFRAIRE RODRIGUES

    2017-01-01

    Full Text Available The development of technologies to increase stand establishment efficiency and seed vigor, as well as to maximize profits, is of fundamental importance for the sustainability of agriculture. Products based on humic substances, such as humic acids, have been recently used in Brazilian agriculture to produce seedlings with high vigor, which positively influences the establishment of the initial stand. Thus, this study aimed to evaluate the effect of treatment of corn seeds with a commercial humic acid-based product, Humykos® (18% of humic acid content, on germination and seedling vigor. The treatments consisted of six doses (0, 100, 200, 300, 400, and 500 mL 100 kg-1 seed of Humykos®, and the treated seeds were analyzed for germination and vigor (first count, emergence, emergence speed index, length, and dry mass of shoots and roots. Our results show that humic acid promotes greater seedling growth and increased shoot dry mass in corn; in addition, it has a positive influence on the emergence speed index up to a dose 158 mL 100 kg-1 seeds.

  4. Effects of the humic acid extracted from vermicompost on the ...

    African Journals Online (AJOL)

    Felipe Andrade

    2015-05-06

    May 6, 2015 ... To this effect, auxin promotes acid growth of plants in which the cell elongation and the consequent increase in length of the plants is a function of cell turgor. This increased growth promoted by humic acid can be of great importance in the early growth of brachiaria seedlings, promoting rapid establishment ...

  5. Possibilities of using humic acid in diets for Saanen goats

    Directory of Open Access Journals (Sweden)

    Taskin Degirmencioglu

    2012-12-01

    Full Text Available This study was carried out to determine the effect of diets containing humic acid at different levels on some blood and milk components in Saanen goats. Saanen goats (2 years old, 52 kg live body weight were fed three diets, containing 0 g kg-1 humic acid (T1, 1 g kg-1 humic acid (T2 and 3 g kg-1 humic acid (T3 in a 3x3 Latin square design experiment. Compared to the control group, T1 - treated group produced more milk/day (P<0.05; 2.45 vs. 2.11 kg d-1 and this yield was similar to that of T2 - treated group. The fat (3.55, 3.67 and 3.58 %, non-fat solids (SNF (8.41, 8.30 and 8.58 %, protein (3.73, 3.60 and 3.92 % and lactose percentages of milk (3.82, 3.83 and 3.77 were similar for T1, T2 and T3 groups. Humic acid administration significantly reduced total cholesterol in blood (P<0.05; 124.1, 100.8 and 102.2 mg dL-1 for T1, T2 and T3, respectively. The LDL cholesterol levels in blood serum of T1, T2 and T3 groups were 23.49, 15.14 and 16.19 mg dL-1, respectively (P<0.05. Further investigation is required to elucidate the effects of humic acid on goat performance.

  6. Effects of fulvic acid and humic acid on aluminum speciation in drinking water.

    Science.gov (United States)

    Wang, Wendong; Yang, Hongwei; Wang, Xiaochang; Jiang, Jing; Zhu, Wanpeng

    2010-01-01

    This article focused on the influences of fulvic acid and humic acid on aluminum speciation in drinking water. Factors including the concentration of residual chlorine and pH value had been concerned. Aluminum species investigated in the experiments included inorganic mononuclear, organic mononuclear, mononuclear, polymer, soluble, and suspended forms. It was found that the effects of fulvic acid and humic acid on aluminum speciation depended mainly on their molecular weight. Fulvic acid with molecular weight less than 5000 Dalton had little influence on aluminum speciation; while fulvic acid with molecular weight larger than 5000 Dalton and humic acid would increase the concentration of soluble aluminum significantly even at concentration below 0.5 mg/L (calculated as TOC). Aluminum species, in the present of fulvic acid with molecular weight larger than 5000 Dalton and humic acid, were more stable than that in the present of fluvic acid with molecular mass less than 5000 Dalton, and varied little with reaction time. Within pH range 6.5-7.5, soluble aluminum increased notably in water with organic matter. As the concentration of residual chlorine increased, the effects of fulvic acid and humic acid became weak. The reactions between humic acid, fulvic acid with large molecular weight, and aluminum were considered to be a multi-dentate coordination process. With the consideration of aluminum bioavailability, reducing the concentration of fulvic acid and humic acid and keeping the pH value among 6.5-7.5 were recommended during drinking water treatment.

  7. Cotransport of bacteria with hematite in porous media: Effects of ion valence and humic acid.

    Science.gov (United States)

    Yang, Haiyan; Ge, Zhi; Wu, Dan; Tong, Meiping; Ni, Jinren

    2016-01-01

    This study investigated the influence of multiple colloids (hematite and humic acid) on the transport and deposition of bacteria (Escherichia coli) in packed porous media in both NaCl (5 mM) and CaCl2 (1 mM) solutions at pH 6. Due to the alteration of cell physicochemical properties, the presence of hematite and humic acid in cell suspensions significantly affected bacterial transport and deposition in quartz sand. Specifically, the presence of hematite (5 mg/L) decreased cell transport (increased cell deposition) in quartz sand in both NaCl and CaCl2 solutions, which could be attributed to the less negative overall zeta potentials of bacteria induced by the adsorption of positively charged hematite onto cell surfaces. The presence of a low concentration (0.1 mg/L) of humic acid in bacteria and hematite mixed suspensions reduced the adsorption of hematite onto cell surfaces, leading to increased cell transport in quartz sand in NaCl solutions, whereas, in CaCl2 solutions, the presence of 0.1 mg/L humic acid increased the formation of hematite-cell aggregates and thus decreased cell transport in quartz sand. When the concentration of humic acid was increased to 1 mg/L, enhanced cell transport was observed in both NaCl and CaCl2 solutions. The decreased adsorption of hematite onto cell surfaces as well as the competition of deposition sites on quartz sand with bacteria by the suspended humic acid contributed to the increased cell transport. Copyright © 2015 Elsevier Ltd. All rights reserved.

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

    Energy Technology Data Exchange (ETDEWEB)

    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/sub 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 (..cap alpha..) increased. The binding data required a fit of two stability constants, ..beta../sub 1/ and ..beta../sub 2/, such that for Eu, log ..beta../sub 1/ = 8.86 ..cap alpha.. + 4.39, log ..beta../sub 2/ = 3.55 ..cap alpha.. + 11.06 while for Am, log ..beta../sub 1/ = 10.58 ..cap alpha.. + 3.84, log ..beta../sub 2/ = 5.32 ..cap alpha.. + 10.42. With hydroxide, carbonate, and humate as competing ligands, the humate complex associated with the ..beta../sub 1/ constant is calculated to be the dominant species for the trivalent actinides and lanthanides under conditions present in natural waters.

  9. The ternary system U(VI) / humic acid / Opalinus Clay

    Energy Technology Data Exchange (ETDEWEB)

    Joseph, Claudia

    2013-07-23

    The storage of nuclear waste in deep geological formations is discussed worldwide as the main strategy for nuclear waste management. To ensure the confinement of the nuclear waste, a multiple barrier system which consists of engineered, geo-engineered, and geological barriers will be applied. Thereby, in Germany the definition of the isolating rock zone represents an important safety function indicator. Clay rock is internationally investigated as potential host rock for a repository and represents a part of the geological barrier. In the present work, the natural clay rock Opalinus Clay from the Mont Terri rock laboratory, Switzerland, was studied. In Germany, the direct disposal of the spent nuclear fuel without the reprocessing of the spent fuel is preferred. In case of water ingress, radionuclides can be released from the nuclear waste repository into its surroundings, namely the host rock of the repository. Humic acids, ubiquitous in nature, can be found associated with the inorganic components in natural clay rock (1.5 x 10{sup -3} wt.% in Opalinus Clay). They can be released under certain conditions. Due to their variety of functional groups, humic acids are very strong complexing agents for metal ions. They have inherent redox abilities and a colloidal conformation in solution. Because of these characteristics, humic acids can affect the mobility of metal ions such as actinides. Furthermore, in the near-field of a repository elevated temperatures have to be considered due to the heat production resulting from the radioactive decay of the various radionuclides in the nuclear waste. This work focuses on the interaction of uranium, as main component of spent nuclear fuel, with Opalinus Clay and studies the influence of humic acid and elevated temperature on this interaction. Thus, the collected sorption and diffusion data are not only relevant for safety assessment of nuclear waste repositories but also for any clay-containing system present in the environment

  10. 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

    greatest impact on the number of pods. The results showed that treatment with 1000 mg/l salicylic acid and humic acid had the greatest effect on stem diameter. Conclusion: The results of this study indicated that low concentrations of salicylic acid increased plant height, the number of leaves, chlorophyll content and stomatal conductance, which can increase plant resistance against unfavorable environmental conditions. As a result, the plants treated with salicylic acid can be increased two driven in adverse environmental conditions. The treatment of humic acid by increasing the rate of photosynthesis and increases the amount of material available for plant growth. This increase can accelerate the growth of the main branch and side periwinkle plant medicinal plants and enhances the appearance of the plant.

  11. 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.

  12. Impact of humic acids on EYL liposome membranes: ESR method

    Directory of Open Access Journals (Sweden)

    Pytel Barbara

    2015-07-01

    Full Text Available In this paper, the effects of model (commercial and natural (extracted from peat humic substances on the membrane of liposomes formed with egg yolk lecithin (EYL are presented. In our research, mass concentrations of fulvic and humic acids were used, which in relation to lecithin varied from 0% to 13%. To study membrane fluidity, electron spin resonance (EPR was used with two spin probes, penetrating various regions of the lipid bilayer. The effects of model and natural humic substances (humic acids – HAs and fulvic acids – FAs on the lipid membrane in different regions were researched: the lipid-water interphase, and in the middle of the lipid bilayer. It was shown that FA and HA impact the fluidity of liposome membranes in different ways. Increased mass concentrations of HAs decreased membrane fluidity in both acids: extracted from peat and the model. However, increased mass concentration of FAs extracted from peat, decreased membrane fluidity in the surface region, at the same time stiffening the central part of the bilayer. Increasing the concentration of FAs extracted from peat had the opposite effect when compared to model FA. This effect may be related to the complexation of xenobiotics present in the soil environment and their impact on biological membranes.

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

    African Journals Online (AJOL)

    This paper discussed the potential role of humic acids (HA) in preventing oxidative stress in rice plants submitted to water stress. The rice seedlings (Oryza sativa L. cv. IACUB-30) was grown in nutrient solution and HA were extracted from vermicompost and analysed using Fourier-transform infrared (FTIR) spectroscopic ...

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

    African Journals Online (AJOL)

    FEA

    2014-02-24

    Feb 24, 2014 ... Humic acids (HA), a component of the organic matter in soil, are the soil fraction that is most resistant to ... the most active fractions of organic matter and affect a variety of chemical, physical, and biological ..... pH, Temperature, Botanicals, Fungicides and Mutagenic Agent. Indian J. Plant Prot. 36:279-282.

  15. 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, ...

  16. Electric condensation of divalent counterions by humic acid nanoparticles

    NARCIS (Netherlands)

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

    2016-01-01

    Experimental data for divalent counterion binding by soil humic acid nanoparticles are set against ion distributions as ensuing from continuous Poisson–Boltzmann electrostatics and a two-state condensation approach. The results demonstrate that Poisson–Boltzmann massively underestimates the extent

  17. Accumulation of humic acid in DET/DGT gels

    NARCIS (Netherlands)

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

    2010-01-01

    Gel layer based sensors are increasingly employed for dynamic trace metal speciation analysis in aquatic and soil media. In DGT (Diffusive Gradient in Thin film), polyacrylamide hydrogels are commonly used for the diffusive gel layer. While some effects of humic and fulvic acids on the DGT detection

  18. 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

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

    NARCIS (Netherlands)

    Koelmans, A.A.; Meulman, B.; Meijer, T.; Jonker, M.T.O.|info:eu-repo/dai/nl/175518793

    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

  20. Humic Acid Degradation by ZnO Photocatalyst

    OpenAIRE

    Sekartaji Putri A.; Babel Sandhya

    2016-01-01

    Humic acid (HA) is universally present in soils and natural water resources in a yellow-brown form. HA can react with chlorine during drinking water treatment and produce disinfection byproducts (DBPs), such as trihalomethanes (THMs) and haloacetic acids (HAAs), which are harmful for health. Therefore, HA has to be eliminated from water environment. The photocatalysis is an effective alternative solution for the degradation of HA in a water environment. This research aims to degrade HA from w...

  1. The Acute Effect of Humic Acid on Iron Accumulation in Rats.

    Science.gov (United States)

    Cagin, Yasir Furkan; Sahin, N; Polat, A; Erdogan, M A; Atayan, Y; Eyol, E; Bilgic, Y; Seckin, Y; Colak, C

    2016-05-01

    Free iron leads to the formation of pro-oxidant reactive oxygen species (ROS). Humic acids (HAs) enhance permeability of cellular wall and act as a chelator through electron transferring. This study was designed to test chelator effect of HA on iron as well as its anti-oxidant effect against the iron-induced hepatotoxicity and cardiotoxicity. The rats used were randomly divided into four groups (n = 8/group): group I (the control group); group II (the HA group), humic acid (562 mg/kg) was given over 10 days by oral gavage; group III (the iron group), iron III hydroxide polymaltose (250 mg/kg) was given over 10 days by intraperitoneal route; and group IV (the HA plus iron group), received the iron (similar to group II) plus humic acid (similar to those in groups II and III) group. Blood and two tissue samples both from liver and heart were obtained for biochemical and histopathological evaluations. Iron deposition, the iron-induced hepatotoxicity, and cardiotoxicity were demonstrated by histopathological and biochemical manner. However, no significant differences were observed in the serum biochemical values and the histopathological results among the iron and the HA plus iron groups in the liver tissue but not in the heart tissue. The protective effects of humic acid against iron-induced cardiotoxicity were shown but not against hepatotoxicity in our study.

  2. Impact of humic acid fouling on membrane performance and transport of pharmaceutically active compounds in forward osmosis.

    Science.gov (United States)

    Xie, Ming; Nghiem, Long D; Price, William E; Elimelech, Menachem

    2013-09-01

    The impact of humic acid fouling on the membrane transport of two pharmaceutically active compounds (PhACs) - namely carbamazepine and sulfamethoxazole - in forward osmosis (FO) was investigated. Deposition of humic acid onto the membrane surface was promoted by the complexation with calcium ions in the feed solution and the increase in ionic strength at the membrane surface due to the reverse transport of NaCl draw solute. The increase in the humic acid deposition on the membrane surface led to a substantial decrease in the membrane salt (NaCl) permeability coefficient but did not result in a significant decrease in the membrane pure water permeability coefficient. As the deposition of humic acid increased, the permeation of carbamazepine and sulfamethoxazole decreased, which correlated well with the decrease in the membrane salt (NaCl) permeability coefficient. It is hypothesized that the hydrated humic acid fouling layer hindered solute diffusion through the membrane pore and enhanced solute rejection by steric hindrance, but not the permeation of water molecules. The membrane water and salt (NaCl) permeability coefficients were fully restored by physical cleaning of the membrane, suggesting that humic acid did not penetrate into the membrane pores. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

  3. Mid-Infrared Spectroscopic Properties of Humic Acid and Fulvic Acid-Soil Mixtures.

    Science.gov (United States)

    The detection of humic materials in soils is essential in order to determine organic matter (SOM) stability and C sequestration on agricultural land. Mid-Infrared (MidIR) spectroscopy has been used to characterize SOM quality [1], study extracted soil humic acids [2], develop calibrations for quanti...

  4. Enzymatically mediated incorporation of 2-chlorophenol 4-chlorophenol into humic acids

    DEFF Research Database (Denmark)

    Lassen, P.; Randall, A.; Jørgensen, O.

    1994-01-01

    A possible route to chlorinated humic substances in the environment, is an indirect chlorination of humic material by enzymatically mediated incorporation of low molecular weight organo-chlorine compounds into the humic skeleton. The enzymatically mediated incorporation of 2-chlorophenol and 4-ch......-chlorophenol into humic acids by Horseradish Peroxidase is reported. The incorporation is accompanied by a significant polymerization of the chlorophenols. The stability of the chlorinated humic acids as well as the environmental implication are discussed.......A possible route to chlorinated humic substances in the environment, is an indirect chlorination of humic material by enzymatically mediated incorporation of low molecular weight organo-chlorine compounds into the humic skeleton. The enzymatically mediated incorporation of 2-chlorophenol and 4...

  5. 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.

  6. Evolution of humic acid-like and core-humic acid-like during high-rate composting of pig faeces amended with wheat straw

    NARCIS (Netherlands)

    Genevini, P.; Adani, F.; Veeken, A.H.M.

    2002-01-01

    The changes in the absolute amounts and in the composition of humic acid-like (RA-like) and core-humic acid-like (core-RA-like) were monitored for the high-rate composting process (4 weeks) of wheat straw-amended pig faeces. Absolute amounts of HA-like and core-HA-like were obtained by extraction of

  7. Qualitative modifications of humic acid-like and core-humic acid-like during high-rate composting of pig faces amended with wheat straw

    NARCIS (Netherlands)

    Genevini, P.; Adani, F.; Veeken, A.H.M.

    2002-01-01

    Humic acid-like (RA-like) and core-humic acid-like (core-RA-like) were characterized during the high-rate composting process by CP-MAS C-13 NMR, pyrolysis-gas chromatography (GC) / mass spectrometry (MS), and elemental analysis. Results obtained indicated that humification proceeded through a

  8. Effect of humic acid on transformation of soil heavy metals

    Science.gov (United States)

    Wu, Shengzhe; Li, Rui; Peng, Shuyang; Liu, Qiuyong; Zhu, Xi

    2017-06-01

    The pattern of transformation among different fractions of heavy metals in soil draws great attention. This article investigated the effect of humic acid on soil heavy metal under different pH and temperature. The results showed that with the increasing of the concentration of humic acid, the concentration of available Cu, Pb decreased greatly, though the decrease of available Cd was light. Also, pH of soil had certain impact on the concentration of available Cu, Pb, Cd while the influence of environmental temperature was minor. The removal efficiency of contaminated soil was 57.283% (Cu), 2.645% (Cd) and 15.485% (Pb) while it could reach more than 98% in contaminated solution.

  9. 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.

  10. 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...

  11. 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.

  12. 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.

  13. Modeling the oxidation kinetics of sono-activated persulfate's process on the degradation of humic acid.

    Science.gov (United States)

    Songlin, Wang; Ning, Zhou; Si, Wu; Qi, Zhang; Zhi, Yang

    2015-03-01

    Ultrasound degradation of humic acid has been investigated in the presence of persulfate anions at ultrasonic frequency of 40 kHz. The effects of persulfate anion concentration, ultrasonic power input, humic acid concentration, reaction time, solution pH and temperature on humic acid removal efficiency were studied. It is found that up to 90% humic acid removal efficiency was achieved after 2 h reaction. In this system, sulfate radicals (SO₄⁻·) were considered to be the mainly oxidant to mineralize humic acid while persulfate anion can hardly react with humic acid directly. A novel kinetic model based on sulfate radicals (SO₄⁻·) oxidation was established to describe the humic acid mineralization process mathematically and chemically in sono-activated persulfate system. According to the new model, ultrasound power, persulfate dosage, solution pH and reaction temperature have great influence on humic acid degradation. Different initial concentration of persulfate anions and humic acid, ultrasonic power, initial pH and reaction temperature have been discussed to valid the effectiveness of the model, and the simulated data showed new model had good agreement with the experiments data.

  14. 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.

  15. Characterization of humic acids from tundra soils of northern Western Siberia by electron paramagnetic resonance spectroscopy

    Science.gov (United States)

    Chukov, S. N.; Ejarque, E.; Abakumov, E. V.

    2017-01-01

    Humic acids from polar soils—cryozems (Cryosols), gleyezems (Gleysols), and peat soils (Histosols)—have been studied by electron paramagnetic resonance spectroscopy. First information was acquired on the content of free radicals in humic acids from polar soils for the northern regions of Western Siberia (Gydan Peninsula, Belyi Island). It was found that polar soils are characterized by higher contents of free radicals than other zonal soils. This is related to the lower degree of humification of organic matter and the enhanced hydromorphism under continuous permafrost conditions. The low degree of organic matter humification in the cryolithozone was confirmed by the increased content of free radicals as determined by electron paramagnetic resonance, which indicates a low biothermodynamic stability of organic matter.

  16. 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

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

    African Journals Online (AJOL)

    NWUUser

    2017-10-17

    Oct 17, 2017 ... acids, including humic acids, have variable physical and chemical properties that allow them to influence gastronomic ... enzymes and humic acid salts inclusion in canola-based diets on organ and bone development in broilers is scarce. ..... As observed in other studies, the type of rickets could not be.

  18. Influence of Humic Acids Extracted from Peat by Different Methods on Functional Activity of Macrophages in Vitro.

    Science.gov (United States)

    Trofimova, E S; Zykova, M V; Ligacheva, A A; Sherstoboev, E Y; Zhdanov, V V; Belousov, M V; Yusubov, M S; Krivoshchekov, S V; Danilets, M G; Dygai, A M

    2017-04-01

    We studied activation of macrophages with humic acids extracted from peat of large deposits in the Tomsk region by two extraction methods: by hydroxide or sodium pyrophosphate. Humic acid of lowland peat types containing large amounts of aromatic carbon, phenolic and alcohol groups, carbohydrate residues and ethers, irrespectively of the extraction methods contained LPS admixture that probably determines their activating properties. Humic acid of upland peat types characterized by high content of carbonyl, carboxyl, and ester groups enhance NO production and reduce arginase expression, but these effects were minimized when sodium hydroxide was used as an extraction solvent. Pyrophosphate samples of the upland peat types were characterized by aromaticity and diversity of functional groups and have a significant advantage because of they induce specific endotoxin-independent stimulating action on antigen presenting cells.

  19. Colloidal behavior of goethite nanoparticles modified with humic acid and implications for aquifer reclamation

    Science.gov (United States)

    Tiraferri, Alberto; Saldarriaga Hernandez, Laura Andrea; Bianco, Carlo; Tosco, Tiziana; Sethi, Rajandrea

    2017-03-01

    Nanosized colloids of iron oxide adsorb heavy metals, enhance the biodegradation of contaminants, and represent a promising technology to clean up contaminated aquifers. Goethite particles for aquifer reclamation were recently synthesized with a coating of humic acids to reduce aggregation. This study investigates the stability and the mobility in porous media of this material as a function of aqueous chemistry, and it identifies the best practices to maximize the efficacy of the related remediation. Humic acid-coated nanogoethite (hydrodynamic diameter ˜90 nm) displays high stability in solutions of NaCl, consistent with effective electrosteric stabilization. However, particle aggregation is fast when calcium is present and, to a lesser extent, also in the presence of magnesium. This result is rationalized with complexation phenomena related to the interaction of divalent cations with humic acid, inducing rapid flocculation and sedimentation of the suspensions. The calcium dose, i.e., the amount of calcium ions with respect to solids in the dispersion, is the parameter governing stability. Therefore, more concentrated slurries may be more stable and mobile in the subsurface than dispersions of low particle concentration. Particle concentration during field injection should be thus chosen based on concentration and proportion of divalent cations in groundwater.

  20. Preparation of fulvic acid and low-molecular organic acids by oxidation of weathered coal humic acid

    Energy Technology Data Exchange (ETDEWEB)

    Shinozuka, T.; Ito, A.; Sasaki, O.; Yazawa, Y.; Yamaguchi, T. [Chiba Institute of Technolgy, Chiba (Japan). Dept. of Industrial Chemistry

    2002-07-01

    Weathered coal contains much humic acid and a little fulvic acid. Therefore, the production of fulvic acid, the most valuable humic substance because of its water-solubility, was examined by ozone and hydrogen peroxide oxidation of humic acid extracted form Xinjiang (China) weathered coal. The resulting products of the oxidation were water soluble fulvic acid and organic acids, mainly formic acid and oxalic acid. The product yield of fulvic acid was 20 (C%) and that of organic acids were 39 (C%) for formic and acid 13 (C%) for oxalic acid. The formed fulvic acid showed a higher content of oxygen and carboxyl groups, than those of the extracted one from the original weathered coal.

  1. 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

  2. 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.

  3. 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

  4. Reduction and Reoxidation of Humic Acid: Influence on Spectroscopic Properties and Proton Binding

    Energy Technology Data Exchange (ETDEWEB)

    Maurer, F.; Christl, I; Kretzschmar, R

    2010-01-01

    Previous studies on proton and metal binding to humic substances have not considered a potential influence of reduction and oxidation of functional groups. Therefore, we investigated how proton binding of a purified soil humic acid was affected by reduction. Reduction of the humic acid was carried out using an electrochemical cell that allowed us to measure the amounts of electrons and protons involved in reduction reactions. We further applied spectroscopic methods (UV-vis, fluorescence, FT-IR, C-1s NEXAFS) to detect possible chemical changes in the humic acid induced by reduction and reoxidation. The effect of reduction on proton binding was determined with acid-base titrations in the pH range 4-10 under controlled redox conditions. During reduction, 0.54 mol kg{sup -1} protons and 0.55 mol kg{sup -1} electrons were transferred to humic acid. NICA-Donnan modeling revealed an equivalent increase in proton-reactive sites (0.52 mol kg{sup -1}) in the alkaline pH-range. Our results indicate that reduction of humic acid increased the amount of proton-reactive sites by 15% compared to the untreated state. Spectroscopic differences between the untreated and reduced humic acid were minor, apart from a lower UV-vis absorption of the reduced humic acid between 400 and 700 nm.

  5. 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.

  6. 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

  7. Natural and pyrogenic humic acids at goethite and natural oxide surfaces interacting with phosphate

    NARCIS (Netherlands)

    Hiemstra, T.; Mia, S.; Duhaut, P.B.; Molleman, B.

    2013-01-01

    Fulvic and humic acids have a large variability in binding to metal (hydr) oxide surfaces and interact differently with oxyanions, as examined here experimentally. Pyrogenic humic acid has been included in our study since it will be released to the environment in the case of large-scale application

  8. Effects of Applying Humic Acids and Bio-fertilizer on the Qualities and Yields of Strawberry and Soil Agrochemical Characters

    OpenAIRE

    LIU Ji-pei; LIU Wei-yi; ZHOU Jie; LI Tong; ZHAO Yue; ZHANG Meng

    2015-01-01

    A greenhouse experiment was conducted to study the effect of humic acids and bio-fertilizer on the qualities, yields of strawberry and soil agrochemical characters. Humic acids and bio-fertilizer were applied based on the requirement of the normal growth of strawberry. Four treatments were plotted: control(conventional treatment), dressing humic acid, topdressing bio-fertilizer, dressing humic acid+bio-fer-tilizer. Each treatment was repeated three times and randomly arranged. Results showed ...

  9. Organic matter source discrimination by humic acid characterization: synchronous scan fluorescence spectroscopy and Ferrate(VI).

    Science.gov (United States)

    Horst, Carolyn; Sharma, Virender K; Baum, J Clayton; Sohn, Mary

    2013-02-01

    In this study, seven soil and sedimentary humic acid samples were analyzed by synchronous scan fluorescence (SSF) spectroscopy. The spectra of these humic acids were compared to each other and characterized, based on three major SSF peaks centered at approximately 281, 367 and 470 nm. Intensity ratios were calculated based on these peaks that were used to numerically assist in source discrimination. All humic acid samples were then reacted with Ferrate(VI) and were again analyzed with SSF. Upon the addition of Ferrate(VI) SSF spectra were obtained which more readily differentiated humic acid source. This method will assist geochemists and water management districts in tracing sources of organic matter to receiving water bodies and may aid in the elucidation of the chemical nature of humic acids. Copyright © 2012 Elsevier Ltd. All rights reserved.

  10. [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.

  11. Forms and lability of phosphorus in humic and fulvic acids

    Science.gov (United States)

    Humic substances are involved in many biological and ecological processes in soils and natural waters. Characterization of phosphorus (P) associated with humic substances may shed light on the function of humic substances in P cycling and nutrition. In this chapter, we review and discuss the forms a...

  12. Formation of aryl-chlorinated aromatic acids and precursors for chloroform in chlorination of humic acid

    NARCIS (Netherlands)

    Sinninghe Damsté, J.S.; Leer, E.W.B. de; Galan, L.

    1985-01-01

    The formation of chloroform when humic substances are chlorinated is well known. Other chlorinated products that may be formed are chloral, di- and trichloroacetic acid, chlorinated C-4 diacids, and α-chlorinated aliphatic acids. Several of these compounds are formed in molar yields comparable

  13. Comparison of some spectroscopic and physico-chemical properties of humic acids extracted from sewage sludge and bottom sediments

    Science.gov (United States)

    Polak, J.; Bartoszek, M.; Sułkowski, W. W.

    2009-04-01

    Comparison of the physico-chemical properties was carried out for humic acids extracted from sewage sludge and bottom sediments. The isolated humic acids were investigated by means of EPR, IR, UV/vis spectroscopic methods and elementary analysis AE. On the basis of earlier studies it was stated that humic acids extracted from sewage sludge can be divided into humic acids extracted from raw sewage sludge and from sewage sludge after the digestion process. The digestion process was found to have the most significant effect on the physico-chemical properties of humic acids extracted from sludge during sewage treatment. Humic acids extracted from sewage sludge had higher free radical concentration than humic acid extracted from bottom sediments. Values of the g-factor were similar for all studied samples. However, it is noteworthy that g-factor values for humic acid extracted from raw sewage sludge and from bottom sediments were lower in comparison to the humic acid extracted from sewage sludge after the fermentation processes. The IR spectra of all studied humic acids confirmed the presence of functional groups characteristic for humic substances. It was also observed that humic acids extracted from bottom sediments had a more aromatic character and contained less carbon, nitrogen and hydrogen than those extracted from the sewage sludge.

  14. The effect of humic and glutamic acids in nutrient solution on the N metabolism in lettuce.

    Science.gov (United States)

    Haghighi, Maryam

    2012-12-01

    This paper reports for the first time the influence of partially replacing the nitrogen (N) source of a nutrient solution with amino acids and humic acid on the physiological and antioxidant activities and N metabolism in lettuce. A hydroponic experiment was designed to replace 25 and 50% of the N in nutrient solutions (NSs) with glutamic acid (GA) and humic acid (HA) and evaluate the effects on growth, nitrate (NO(3)) assimilation, protein content, nitrate reductase (NR) activity and antioxidant changes in lettuce. The results showed that, when a portion of the N was replaced with GA and HA, the fresh and dry weights of lettuce shoots did not change significantly compared with the full NO(3) treatment. The titratable acidity was not affected by adding HA and/or GA to the NS. The nitrite concentration and NR activity decreased with reductions in the N concentration of the NS and improved with the addition of GA and HA. GA enhanced the NO(3) uptake and protein content more than HA. Changes in the superoxide dismutase (SOD) and peroxidase (POD) activities and malondialdehyde content were inconclusive: SOD and POD activities decreased with decreasing N content of the NS, and HA addition improved the SOD and POD activities. When HA and GA were substituted for NO(3) in an NS, the acids effectively adjusted the N metabolism and growth in lettuce and decreased the N consumption of the NS. Copyright © 2012 Society of Chemical Industry.

  15. 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.

  16. Functional groups and reactivity of size-fractionated Aldrich humic acid

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Tadao, E-mail: tanaka.tadao26@jaea.go.jp [Nuclear Safety Research Center, Japan Atomic Energy Agency, Shirakata 2-4, Tokai, Naka, Ibaraki, 319-1195 (Japan)

    2012-03-20

    The complexation affinity of the Aldrich Chemicals humic acid with {sup 60}Co was examined with respect to molecular size of humic acid. Correlations between the affinity and the structures of humic acid were studied. At low humic acid concentration range, {sup 60}Co was interacted with the humic acid of size fraction over 100k Da (HA(100<)). With increasing humic acid concentration, the {sup 60}Co was preferentially interacted with the 30k-100k Da of humic acid (HA(30-100)). Fractionated HA(100<) and HA(30-100) were characterized from their FTIR (Fourier Transform Infra-Red), {sup 13}C NMR spectral analyses and acid-base titration curves. The HA(10<) having aliphatic branched structure, smaller amount of COOH group and large proton exchangeable capacity, seem to show low covalent bonding nature and high ion exchangeability in the complexation. In addition, steric hindrance may affect on the complexation, by winding up like random coils from the branched structure. The HA(30-100) is dominated with the aromatic COOH group and OH group and it may preferentially coordinate to {sup 60}Co by covalent binding. These presumptions were supported by XPS analysis, in which the biding energy of cobalt-humates was discussed.

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

    Directory of Open Access Journals (Sweden)

    S Sabzevari

    2011-01-01

    Full Text Available 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 concentration (0, 36, 54, and 72 mg/l and wheat cultivars (Sayons, Chamran, Pishtaz and Sabalan. Results showed that all traits except germination rate were significantly different (p

  18. 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...

  19. Interpretation of humic acid coagulation and soluble soil organic matter using a calculated electrostatic potential

    NARCIS (Netherlands)

    Weng, L.P.; Temminghoff, E.J.M.; Riemsdijk, van W.H.

    2002-01-01

    The coagulation of humic substances and its role in controlling the solubility of organic matter in soils are not well understood. We therefore studied the physico-chemical behaviour of purified humic acid from forest soil coagulated with Na, Ca, Cu, Al at pH 4 and 6, and then modelled the behaviour

  20. Hollow fiber dead-end ultrafiltration: Axial transport variations during humic acid filtration

    NARCIS (Netherlands)

    van de Ven, W.J.C.; van 't Sant, K.; Punt, Ineke G.M.; Zwijnenburg, A.; Kemperman, Antonius J.B.; van der Meer, Walterus Gijsbertus Joseph; Wessling, Matthias

    2008-01-01

    This paper describes the dead-end ultrafiltration of humic substances with hollow fiber modules. We show that the resistance of a fouling layer decreases with increasing flux. The lower resistance of the fouling layer is caused by a loss in retention of the membrane for humic acid at these higher

  1. Evaluation of a proposed standardized analytical method for the determination of humic and fulvic acids in commercial products

    Science.gov (United States)

    A constraint to growth of the commercial humic products industry has been the lack of a widely accepted procedure for determining humic acid and fulvic acid concentrations of the products, which has raised regulatory issues. On behalf of the U.S.-based Humic Products Trade Association, we developed ...

  2. 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.)

  3. 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.

  4. Thermodynamic Characterization of Humic Acid-surfactant Interaction: New Insights into the Characteristics and Structure of Humic Acids

    Directory of Open Access Journals (Sweden)

    Leonardus Vergütz

    2015-12-01

    Full Text Available ABSTRACT Humic acids (HA are a component of humic substances (HS, which are found in nearly all soils, sediments, and waters. They play a key role in many, if not most, chemical and physical properties in their environment. Despite the importance of HA, their high complexity makes them a poorly understood system. Therefore, understanding the physicochemical properties and interactions of HA is crucial for determining their fundamental role and obtaining structural details. Cationic surfactants are known to interact electrostatically and hydrophobically with HA. Because they are a very well-known and characterized system, they offer a good choice as molecular probes for studying HA. The objective of this study was to evaluate the interaction between cationic surfactants and HA through isothermal titration calorimetry in a thermodynamic manner, aiming to obtain information about the basic structure of HA, the nature of this interaction, and if HA from different origins show different basic structures. Contrary to what the supramolecular model asserts, HA structure is not loosely held, though it may separate depending on the conditions the HA are subjected to in their milieu. It did not show any division or conformational change when interacting with surfactants. The basic structure of the HA remains virtually the same regardless of the different sources and compositions of these HA.

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

    Science.gov (United States)

    Katsumi, Naoya; 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 12h. 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, (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. Copyright © 2015 Elsevier B.V. All rights reserved.

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

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    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.

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

    Science.gov (United States)

    Azman, Samet; Khadem, Ahmad F.; Zeeman, Grietje; van Lier, Jules B.; Plugge, Caroline 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 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. PMID:28955013

  8. 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

  9. 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.

  10. 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

  11. Effect of mechanochemical modification on the surfactant and structural properties of humic and himatomelanic acids

    Science.gov (United States)

    Mal'tseva, E. V.; Shekhovtsova, N. S.; Shilyaeva, L. P.; Yudina, N. V.

    2017-07-01

    The structural properties of humic and himatomelanic acids are studied by means of 1H NMR spectroscopy and differential thermal analysis after mechanochemical modification of peat. The relationship between the structural modification of humic and himatomelanic acids and their surfactant properties in aqueous solutions is established. It is shown that the critical micelle concentration of transformed himatomelanic acids is halved in comparison to the initial sample, while the adsorption equilibrium constant grows by 9 times.

  12. Migration of uranium(IV)/(VI) in the presence of humic acids in quartz sand: a laboratory column study.

    Science.gov (United States)

    Mibus, Jens; Sachs, Susanne; Pfingsten, Wilfried; Nebelung, Cordula; Bernhard, Gert

    2007-01-30

    The migration behavior of U(IV) and U(VI) in the presence of humic acid was studied in a quartz sand system. Laboratory column experiments were performed using humic acid, U(VI) in humic acid absence, U(IV) and U(VI) in humic acid presence, and for comparison a conservative tracer. In experiments using humic acid, both redox species of U migrate nearly as fast as the conservative tracer. Humic acid accelerates the U(VI) breakthrough compared to the humic acid-free system. There are strong indications for a similar effect on the U(IV) transport. At the same time, a part of U(IV) and U(VI) associated with the humic acid is immobilized in the quartz sand due to humic colloid filtration thus producing a delaying effect. Tailing at a low concentration level was observed upon tracer elution. The experimental breakthrough curves were described by reactive transport modeling using equations for equilibrium and kinetic reactions. The present study demonstrates that humic acids can play an important role in the migration of actinides. As natural organic matter is ubiquitous in aquifer systems, the humic colloid-borne transport of actinides is of high relevance in performance assessment.

  13. Comparison of Chemical Structure of Alginite Humic Acids Isolated with Two Different Procedures with Soil Humic Acids

    Directory of Open Access Journals (Sweden)

    Barančíková Gabriela

    2016-12-01

    Full Text Available The different origin of alginite and soil organic matter may be the reason of differences in their humic acids (HA chemical structure. One of the aims of this article is to compare the chemical composition of alginite HA and HA isolated from different soil types. Another aim of this article is to compare the chemical structure of humic acids of alginite isolated with two different procedures: modified IHSS (International Humic Substances Society method and simplified extraction method. The modified IHSS method was applied for the isolation of alginite and soil HA. To obtain sufficient amount of alginate HA for biological experiments, simplified extraction method suited for large volumes of HA was applied. The differences in elemental analysis and ash proportion in HA extracted by modified IHSS method (C = 35.4, H = 43 atomic%, ash content = 0.08% and simplified extraction method (C = 31, H = 31 atomic%, ash content = 7.42% can be caused by different concentration of extraction solution and also differences in purification of HA. The differences in chemical structure between alginate HA and HA isolated from different soil types according to the data of elemental analysis (C content of alginite HA = 35.4 atomic%, C content in soils HA = 38.2‒49.1 atomic% and 13C nuclear magnetic resonance (NMR spectra (degree of aromaticity of alginite HA = 24.4% and soil HA= 35.9‒53% were found. Results of 13C NMR show that the content of aromatic carbon was decreasing in the following order: Haplic Chernozem HA > Andic Cambisol HA > Haplic Cambisol HA > alginite HA. Based on the obtained results, it can be concluded that the differences in the chemical structure of alginite and soil HA can be explained by the difference in the origin of organic matter in alginite and soil samples. The source of organic matter in alginite is mainly type II kerogen from algae and that of soil is lignin and cellulose (type III kerogen of higher plants.

  14. TiO2 BEADS FOR PHOTOCATALYTIC DEGRADATION OF HUMIC ACID IN PEAT WATER

    Directory of Open Access Journals (Sweden)

    Winarti Andayani

    2011-12-01

    Full Text Available Degradation of humic acid in aqueous solution containing TiO2 coated on ceramics beads under irradiation of 254 nm UV light has been conducted in batch reactor. The aim of this experiment was to study photocatalytic degradation of humic acid in peat water. The irradiation of the humic acid in aqueous solution was conducted in various conditions i.e solely uv, in the presence of TiO2-slurry and TiO2 beads. The color intensity, humic acid residue, conductivity and COD (chemical oxygen demand of the solution were analyzed before and after irradiation.  The compounds produced during photodegradation were identified using HPLC. The results showed that after photocatalytic degradation, the color intensity and the COD value of the solution decreased, while the conductivity of water increased indicating mineralization of the peat water occurred. In addition, oxalic acid as the product of degradation was observed.

  15. Effect of Mixing Urea with Humic Acid and Acid Sulphate Soil on Ammonia Loss, Exchangeable Ammonium and Available Nitrate

    OpenAIRE

    Mohd T.M. Yusuff; Osumanu H. Ahmed; Nik M.A. Majid

    2009-01-01

    Problem statement: Ammonia loss due to rapid hydrolysis of urea in soil following surface application can be substantial. Ammonia loss in agriculture is estimated to be 1 to 60%. This laboratory study compared the effect of three different urea-humic acid-acid sulphate soil mixtures on NH3 loss and soil ammonium and nitrate contents, with loss from surface applied urea without additives (urea alone). Approach: Humic acid, acid sulfate soil and soil use in the incubation study was analyzed for...

  16. Cd(II) Sorption on Montmorillonite-Humic acid-Bacteria Composites

    National Research Council Canada - National Science Library

    Du, Huihui; Chen, Wenli; Cai, Peng; Rong, Xingmin; Dai, Ke; Peacock, Caroline L; Huang, Qiaoyun

    2016-01-01

    .... Herein, batch sorption isotherms, isothermal titration calorimetry (ITC), and Cd K-edge EXAFS spectroscopy were applied to investigate the binding characteristics of Cd on montmorillonite(Mont)-humic acid(HA...

  17. Study of coagulation processes of selected humic acids under copper ions influence*

    Science.gov (United States)

    Boguta, Patrycja; Sokolowska, Zofia

    2013-04-01

    Humic acids have limited sorption capacity and big dose of metal or other mineral component which can be sorbed on humic acids, can cause saturation of negative, surface charge of humic acids leading to destabilization of dissolved humic acids compounds. Destabilisation can be observed as coagulation and floculation proces of humic acids. However there are a lot of mechanisms which causing precipitation of humic acids. Thereby, in order to full description of coagulation process, different methods should be applied. Ordinarily, humic acids coagulation is studied by measurement of absorbance, transmittance or carbon loss in solution. Meanwhile, very significant information is also variation of metal content in soil solution and information whether metal goes to precipitate together with humic acids or stays in dissolved form in solution. So, that, from one side, processes of stronger accumulation of metal can lead to soil degradation and micronutrient deficiency for plants. However, there is also possibility to stay metal in solution in toxic and bioavailable form for plants. Main aim of this paper was to study coagulation process of different humic acids extracted from mucking peats under copper ions influence at adjusted pH to 5. In order to this, four peaty-muck soils were taken from selected places in east part of Poland (meadows and river valleys). These soils differed by humification degree, secondary transformation, density and pH. At next step, humic acids were extracted from soils using sodium hydroxide (NaOH) extractant. After exact purification by washing with HF-HCl mixture and water, humic acids were liofilized. Solutions of humic acids were prepared at concentration 40 mg/dm3 with addition of different amount of copper ions to obtain final concentration of Cu(II) ranged from 0-40mg/dm3. After 24 hours solutions were investigated using measurements of absorbance at 470nm (UV-VIS spectrometer Jasco V-530), measurements of organic carbon in solution

  18. Decreased solubilization of Pu(IV) polymers by humic acids under anoxic conditions

    Science.gov (United States)

    Xie, Jinchuan; Lin, Jianfeng; Liang, Wei; Li, Mei; Zhou, Xiaohua

    2016-11-01

    Pu(IV) polymer has a very low solubility (log[Pu(IV)aq]total = -10.4 at pH 7.2 and I = 0). However, some aspects of their environmental fate remain unclear. Humic acids are able to complex with Pu4+ ions and their dissolved species (0.57 mg/L). Solubilization of the humic-coated polymers was thus inhibited to a significant extent although EDTA, having the great complexation ability, was present in the humic solutions. Reduction of Pu(IV) polymers by the humic acids was also not observed in the absence of EDTA. In the presence of EDTA, the polymers were partially reduced to Pu(III)aq by the humic acids of 0.57 mg/L and the percentage of Pu(III)aq accounted for 51.7% of the total aqueous Pu. This demonstrates that the humic acids were able to reduce the aqueous Pu(IV), instead of the polymeric Pu(IV). Such a demonstration is supported by the very positive redox potential of aqueous Pu(IV)-EDTA complex: Eho ‧ (PuL24-/PuL25-) = 154.3 mV >>Eh (PuO2 (am) /Pu3+) = -182.7 mV calculated at 10-10 mol/L Pu3+ and pH 7.2. At the higher humic concentrations (>0.57 mg/L), the polymers were reduced to a lesser extent because the much denser humic coatings resulted in lower concentrations of the aqueous Pu(IV). Consequently, humic acids make Pu(IV) polymers pretty stable unless the artificial ligands such as EDTA are present in the groundwater.

  19. A Study of Adsorption Behaviour of Humic Acid and Americium on the Kaolinite

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Myung Ho; Park, Kyung Kyun; Jung, Euo Chang; Song, Kyu Seok [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Shin, Hyun Sang [Department of Environmental Engineering, Seoul National University, Seoul (Korea, Republic of)

    2010-06-15

    In this study, the adsorption reactions in the binary component system such as kaolinite-humic acid, kaolinite-americium and humic acid-americium were investigated. After performing the basic physico-chemical properties of the kaolinite, the adsorption reactions of the humic acid on the kaolinite were carried out with varying concentration of humic acid and ion strength, and pH. With increasing HA concentration and pH, the sorption of HA onto KA decreased, while the sorption of HA onto KA increased with increasing ionic strength. Also, with varying pH, the adsorption reactions of the americium-kaolinite and americium-humic acid were studied. In the acid and neutral region, Am easily adsorbed on the HA, while the sorption of Am on the HA in the alkali region decreased because of electrostatic repulsion. The results from these studies make it possible to understand the characteristics of adsorption behaviour of the americium by the humic acid in the water environment.

  20. 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.

  1. The Role of Concentration and Solvent Character in the Molecular Organization of Humic Acids

    Directory of Open Access Journals (Sweden)

    Martina Klučáková

    2016-10-01

    Full Text Available The molecular organization of humic acids in different aqueous solutions was studied over a wide concentration range (0.01–10 g·dm−3. Solutions of humic acids were prepared in three different media: NaOH, NaCl, and NaOH neutralized by HCl after dissolution of the humic sample. Potentiometry, conductometry, densitometry, and high resolution ultrasound spectrometry were used in order to investigate conformational changes in the humic systems. The molecular organization of humic acids in the studied systems could be divided into three concentration ranges. The rearrangements were observed at concentrations of ~0.02 g·dm−3 and ~1 g·dm−3. The first “switch-over point” was connected with changes in the hydration shells of humic particles resulting in changes in their elasticity. The compressibility of water in the hydration shells is less than the compressibility of bulk water. The transfer of hydration water into bulk water increased the total compressibility of the solution, reducing the ultrasonic velocity. The aggregation of humic particles and the formation of rigid structures in systems with concentrations higher than 1 g·dm−3 was detected.

  2. Humic Acid Degradation by ZnO Photocatalyst

    Directory of Open Access Journals (Sweden)

    Sekartaji Putri A.

    2016-01-01

    Full Text Available Humic acid (HA is universally present in soils and natural water resources in a yellow-brown form. HA can react with chlorine during drinking water treatment and produce disinfection byproducts (DBPs, such as trihalomethanes (THMs and haloacetic acids (HAAs, which are harmful for health. Therefore, HA has to be eliminated from water environment. The photocatalysis is an effective alternative solution for the degradation of HA in a water environment. This research aims to degrade HA from water environment. The rapid degradation of HA, using zinc oxide nanoparticles, irradiated by ultraviolet light (ZnO/UV, is investigated. The optimum conditions of pertinent factors, which include the light wavelength (UV-A and UV-C, and light intensity, HA concentration, ZnO dose, and contact time are investigated at neutral pH conditions, considered for drinking water treatment. HA degradation efficiency reached more than 80% after 60 min for both types of irradiation in optimum conditions of 0.3 g/L ZnO dose in 180 min of contact time. Comparisons for degradation efficiency under UV-A and UV-C irradiation indicate that UV-C has higher efficiency, up to 150 min of contact time. The reusability of catalyst is performed for three reuses and still revealed effective for beneficial commercial applications.

  3. Compost-derived humic acids as regulators for reductive degradation of nitrobenzene.

    Science.gov (United States)

    Yuan, Ying; Xi, Beidou; He, Xiaosong; Tan, Wenbing; Gao, Rutai; Zhang, Hui; Yang, Chao; Zhao, Xinyu; Huang, Caihong; Li, Dan

    2017-10-05

    Nitrobenzene (NB) is a major class of contaminants in soil and groundwater. The current methods involved in the reductive degradation of NB suffer either cost-ineffective or slow conversion rate. Here, we investigated the mechanisms regarding compost-derived humic acids (HAs) as cost-effective regulators to enhance the reduction of NB to aniline (AN). Our results show that the compost-derived HAs, which have been reduced by a Pd-H2 catalytic system, were able to reduce NB to AN, and their redox properties were the main factors governing the reduction of NB to AN. The decreasing reduction of NB was mainly caused by the decreasing phenol content of compost-derived HAs during composting. In addition, the results reveal that the increase in the generation content of AN was mainly attributed to the increase in the quinones, aromaticity and humic-like components of compost-derived HAs. The findings demonstrate that the HAs derived from compost are effective regulators to enhance the reduction of NB to AN, and that they exert a bright application prospect for the remediation of the NB-contaminated soil. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. 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.

  5. 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.

    2017-04-01

    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.

  6. The influence of humic acids derived from earthworm-processed organic wastes on plant growth

    Energy Technology Data Exchange (ETDEWEB)

    Atiyeh, R.M.; Lee, S.; Edwards, C.A.; Arancon, N.Q.; Metzger, J.D. [Ohio State University, Columbus, OH (United States). Soil Ecology Lab.

    2002-08-01

    Some effects of humic acids, formed during the breakdown of organic wastes by earthworms (vermicomposting), on plant growth were evaluated. In the first experiment, humic acids were extracted from pig manure vermicompost using the classic alkali/acid fractionation procedure and mixed with a soilless container medium (Metro-Mix 360), to provide a range of 0, 50, 100, 150, 200, 250, 500, 1000, 2000 and 4000 mg of humate per kg of dry weight of container medium, and tomato seedlings were grown in the mixtures. In the second experiment, humates extracted from pig manure and food wastes vermicomposts were mixed with vermiculite to provide a range of 0, 50, 125, 250, 500, 1000 and 4000 mg of humate per kg of dry weight of the container medium, and cucumber seedlings were grown in the mixtures. Both tomato and cucumber seedlings were watered daily with a solution containing all nutrients required to ensure that any differences in growth responses were not nutrient-mediated. The incorporation of both types of vermicompost-derived humic acids, into either type of soilless plant growth media, increased the growth of tomato and cucumber plants significantly, in terms of plant heights, leaf areas, shoot and root dry weights. Plant growth increased with increasing concentrations of humic acids incorporated into the medium up to a certain proportion, but this differed according to the plant species, the source of the vermicompost, and the nature of the container medium. Plant growth tended to be increased by treatments of the plants with 50-500 mg/kg humic acids, but often decreased significantly when the concentrations of humic acids derived in the container medium exceeded 500-1000 mg/kg. These growth responses were most probably due to hormone-like activity of humic acids from the vermicomposts or could have been due to plant growth hormones adsorbed onto the humates. (author)

  7. Investigation of the Effect of Humic Acids on Phototransformation of Naphthalene Illuminated by Visible and UV Light

    Science.gov (United States)

    Nechaev, L. V.; Tchaikovskaya, O. N.

    2016-04-01

    Results of investigation of the effect of humic acids on the degree of photochemical transformation of naphthalene in an aqueous solution illuminated by model solar and UV light are presented. The constant of complexation of naphthalene and humic acids is determined. It is established that the molecular complex of the humic acid and naphthalene is more stable to illumination by UV light then by model sunlight.

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

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    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.

  9. 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.

  10. [Nitrate nitrogen leaching and residue of humic acid fertilizer in field soil].

    Science.gov (United States)

    Liu, Fang-chun; Xing, Shang-jun; Duan, Chun-hua; Du, Zhen-yu; Ma, Hai-lin; Ma, Bing-yao

    2010-07-01

    To elucidate the potential influence of humic acidfertilizer on groundwater and soil quality in clay soil (CS) and sandy soil (SS), nitrate nitrogen leaching and residue of different fertilizers in field soil were studied using a self-made leaching field device. Nitrate nitrogen concentration in leaching water of fertilizer treatments was 28.1%-222.2% higher than that of non-nitrogen treatment in different times, but humic acid fertilizer could prevent nitrate nitrogen leaching both in CS and SS, especially in CS. Nitrate nitrogen concentration of leaching water in CS was 41.2%-59.1% less than that in SS and the inhibiting effect in CS was greater than that in SS. Nitrate nitrogen could be accumulated in soil profile by fertilizer application. The residue of nitrate nitrogen retained in 0-40 cm soil layer of humic acid fertilizer treatment was 59.8% and 54.4% respectively, higher than that of urea and compound fertilizer treatments. Nitrate nitrogen amount of humic acid, urea and compound fertilizer treatments in SS was significantly less than that in CS, being 81.7%, 81.1% and 47.6% respectively. Compared with the conventional fertilizer, humic acid fertilizer treatment improved the contents of organic matter, available nitrogen, phosphorus, and potassium of upper layer soil as well as cation exchange capacity. Besides, total amount of water-soluble salts in humic acid fertilizer treatment was decreased by 24.8% and 22.5% in comparison to urea and compound fertilizer treatments in CS, respectively. In summary, the application of humic acid fertilizer could improve physical and chemical properties of upper layer soil and reduce the risk of potential pollution to groundwater.

  11. Humic acid from Shilajit – a physico-chemical and spectroscopic characterization

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    SURAJ P. AGARWAL

    2010-03-01

    Full Text Available Shilajit is a blackish–brown exudation, consisting of organic substances, metal ions and minerals, from different formations, commonly found in the Himalayan region (1000–3000 m from Nepal to Kashmir. Shilajit can also be collected throughout the mountain regions in Afghanistan, Bhutan, China, Bajkal, throughout Ural, Caucasus and Altai mountains also, at altitudes between 1000 to 5000 m. The major physiological action of shilajit has been attributed to the presence of bioactive dibenzo-α-pyrones together with humic and fulvic acids, which act as carrier molecules for the active ingredients. In this work, the aim was to extract humic acid from Shilajit from various sources and characterised these humic acids based on their physicochemical properties, elemental analysis, UV/Vis and FTIR spectra, X-ray diffraction pattern and DSC thermograms. The spectral features obtained from UV/Vis, FTIR, XRD and DSC studies for samples of different origins showed a distinct similarity amongst themselves and in comparison to soil humic acids. The surfactant properties of the extracted fulvic acids were investigated by determining the effect of increasing concentration on the surface tension of water. The study demonstrated that humic acids extracted from shilajit indeed possessed surfactant properties.

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

    Science.gov (United States)

    DiDonato, Nicole; Chen, Hongmei; Waggoner, Derek; Hatcher, Patrick G.

    2016-04-01

    Soil humic acids are the base soluble/acid insoluble organic components of soil organic matter. Most of what we know about humic acids comes from studies of their bulk molecular properties or analysis of individual fractions after extraction from soils. This work attempts to better define humic acids and explain similarities and differences for several soils varying in degrees of humification using advanced molecular level techniques. Our investigation using electrospray ionization coupled to Fourier transform ion cyclotron resonance mass spectrometry (ESI-FTICR-MS) and nuclear magnetic resonance spectroscopy (NMR) has given new insight into the distinctive molecular characteristics of humic acids which suggest a possible pathway for their formation. Humic acids from various ecosystems, climate regions and soil textural classes are distinguished by the presence of three predominant molecular components: lignin-like molecules, carboxyl-containing aliphatic molecules and condensed aromatic molecules that bear similarity to black carbon. Results show that humification may be linked to the relative abundance of these three types of molecules as well as the relative abundance of carboxyl groups in each molecular type. This work also demonstrates evidence for lignin as the primary source of soil organic matter, particularly condensed aromatic molecules often categorized as black carbon and is the first report of the non-pyrogenic source for these compounds in soils. We also suggest that much of the carboxyl-containing aliphatic molecules are sourced from lignin.

  13. Humic Acid Composition and Characteristics of Soil Organic Matter in Relation to the Elevation Gradient of Moso Bamboo Plantations.

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    Hsueh-Ching Wang

    Full Text Available Studying the influence of climatic and/or site-specific factors on soil organic matter (SOM along an elevation gradient is important for understanding the response of SOM to global warming. We evaluated the composition of SOM and structure of humic acids along an altitudinal gradient from 600 to 1400 m in moso bamboo (Phyllostachys edulis plantations in central Taiwan using NMR spectroscopy and photometric analysis. Total organic C and total nitrogen (N content increased with increasing elevation. Aromaticity decreased and ΔlogK (the logarithm of the absorbance ratio of humic acids at 400 and 600 nm increased with increasing elevation, which suggests that SOM humification decreased with increasing elevation. High temperature at low elevations seemed to enhance the decomposition (less accumulation of total organic C and N and humification (high aromaticity and low ΔlogK. The alkyl-C/O-alkyl-C (A/O-A ratio of humic acids increased with increasing elevation, which suggests that SOM humification increased with increasing elevation; this finding was contrary to the trend observed for ΔlogK and aromaticity. Such a discrepancy might be due to the relatively greater remaining of SOM derived from high alkyl-C broadleaf litter of previous forest at high elevations. The ratio of recalcitrant C to total organic C was low at low elevations, possibly because of enhanced decomposition of recalcitrant SOM from the previous broadleaf forest during long-term intensive cultivation and high temperature. Overall, the change in SOM pools and in the rate of humification with elevation was primarily affected by changes in climatic conditions along the elevation gradient in these bamboo plantations. However, when the composition of SOM, as assessed by NMR spectroscopy and photometric analysis was considered, site-specific factors such as residual SOM from previous forest and intensive cultivation history could also have an important effect on the humic acid

  14. Humic Acid Composition and Characteristics of Soil Organic Matter in Relation to the Elevation Gradient of Moso Bamboo Plantations.

    Science.gov (United States)

    Wang, Hsueh-Ching; Chou, Chiao-Ying; Chiou, Chyi-Rong; Tian, Guanglong; Chiu, Chih-Yu

    2016-01-01

    Studying the influence of climatic and/or site-specific factors on soil organic matter (SOM) along an elevation gradient is important for understanding the response of SOM to global warming. We evaluated the composition of SOM and structure of humic acids along an altitudinal gradient from 600 to 1400 m in moso bamboo (Phyllostachys edulis) plantations in central Taiwan using NMR spectroscopy and photometric analysis. Total organic C and total nitrogen (N) content increased with increasing elevation. Aromaticity decreased and ΔlogK (the logarithm of the absorbance ratio of humic acids at 400 and 600 nm) increased with increasing elevation, which suggests that SOM humification decreased with increasing elevation. High temperature at low elevations seemed to enhance the decomposition (less accumulation of total organic C and N) and humification (high aromaticity and low ΔlogK). The alkyl-C/O-alkyl-C (A/O-A) ratio of humic acids increased with increasing elevation, which suggests that SOM humification increased with increasing elevation; this finding was contrary to the trend observed for ΔlogK and aromaticity. Such a discrepancy might be due to the relatively greater remaining of SOM derived from high alkyl-C broadleaf litter of previous forest at high elevations. The ratio of recalcitrant C to total organic C was low at low elevations, possibly because of enhanced decomposition of recalcitrant SOM from the previous broadleaf forest during long-term intensive cultivation and high temperature. Overall, the change in SOM pools and in the rate of humification with elevation was primarily affected by changes in climatic conditions along the elevation gradient in these bamboo plantations. However, when the composition of SOM, as assessed by NMR spectroscopy and photometric analysis was considered, site-specific factors such as residual SOM from previous forest and intensive cultivation history could also have an important effect on the humic acid composition and

  15. 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.

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

    Science.gov (United States)

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

    2014-08-01

    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 cells, as well as the mechanisms behind these effects. It was found that 50 mg/L HA showed cytotoxicity, which we considered to be mediated by apoptosis through the mitochondrial pathway because of an increase in the expression of caspases 6 and 9 in response to HA administration. In addition, this cytotoxicity was enhanced when cells in this experimental system were exposed to oxidative stress, while it was decreased by the addition of vitamin C. Thus, we conclude that the apoptosis induced by HA depends upon oxidative stress. Furthermore, an iron chelator, DFO, showed a tendency to decrease HA-induced cytotoxicity, suggesting that iron may potentially mediate HA-induced oxidative stress. In conclusion, long-term consumption of HA-rich water obtained from our study area may cause damage to endothelial cells and subsequent chronic health problems. Copyright © 2012 Wiley Periodicals, Inc., a Wiley company.

  17. 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.

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

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    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.

  19. 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.

  20. Fractionation of humic acids upon adsorption on montmorillonite and palygorskite

    Science.gov (United States)

    Alekseeva, T. V.; Zolotareva, B. N.

    2013-06-01

    The adsorption of three humic acid (HA) preparations by clays—montmorillonite (Wyoming, USA) and palygorskite (Kolomenskoe district, Moscow oblast)—has been studied. The HA preparations were isolated from samples of the humus-accumulative horizons of a leached chernozem (Voronezh) and a chestnut soil (Volgograd), and a commercial preparation of sodium humate (Aldrich) was also used. The solid-state 13C NMR spectroscopy and IR spectroscopy revealed the selective adsorption of structural HA fragments (alkyls, O-alkyls (carbohydrates), and acetal groups) on these minerals. As a result, the aromaticity of the organic matter (OM) in the organic-mineral complexes (OMCs) and the degree of its humification have been found to be lower compared to the original HA preparations. The fractionation of HAs is controlled by the properties of the mineral surfaces. The predominant enrichment of OMCs with alkyls has been observed for montmorillonite, as well as an enrichment with O-alkyls (carbohydrates) for palygorskite. A decrease in the C : N ratio has been noted in the elemental composition of the OM in complexes, which reflected its more aromatic nature and (or) predominant sorption of N-containing structural components of HA molecules. The adsorption of HA preparations by montmorillonite predominantly occurs on the external surface of mineral particles, and the interaction of nonpolar alkyl groups of HAs with this mineral belongs to weak (van der Waals, hydrophobic) interactions. The adsorption of HA preparations by palygorskite is at least partly of chemical nature: Si-OH groups of minerals are involved in the adsorption process. The formation of strong bonds between the OM and palygorskite explains the long-term (over 300 million years) retention of fossil fulvate-type OM in its complex with palygorskite, which we revealed previously.

  1. Humic acid removal from aqueous solutions by peroxielectrocoagulation process

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    Ahmad Reza Yazdanbakhsh

    2015-06-01

    Full Text Available Background: Natural organic matter is the cause of many problems associated with water treatment such as the presence of disinfection by-products (DBPs and membrane fouling during water filtration. In this study, the performance of the peroxi-electrocoagulation process (PEP was investigated for the removal of humic acids (HAs from aqueous solutions. Methods: PEP was carried out for the removal of HA using a plexiglas reactor with a volume of 2 L and fitted with iron electrodes and a direct current supply (DC. Samples were taken at various amounts of pH (2-4, current density (1 and 2A/cm2, hydrogen peroxide (50-150 mg/L and reaction time (5-20 minutes and then filtered to remove sludge formed during reaction. Finally, the HA concentration was measured by UV absorbance at 254 nm (UV254. Results: Results indicated that increasing the concentration of H2O2 from 50 to 150 mg/L increased HA removal efficiency from 83% to 94.5%. The highest removal efficiency was observed at pH 3.0; by increasing the pH to the alkaline range, the efficiency of the process was reduced. It was found that HA removal efficiency was high in current density 1A/cm2. Increasing current density up to 1 A cm-2 caused a decrease in removal efficiency. Results of this study showed that under the optimum operating range for the process ([current density] = 1A/cm2, [hydrogen peroxide concentration] = 150 mg/L, [reaction time]= 20 minutes and [pH]= 3.0, HA removal efficiency reached 98%. Conclusion: It can be concluded that PEP has the potential to be utilized for cost-effective removal of HA from aqueous solutions.

  2. 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

  3. Performance of the catalytic ozonation process with pumice in removal of humic acids from aqueous solutions

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    Ghorban Asgari

    2012-01-01

    Full Text Available Aims: This study was conducted to evaluate the feasibility of applying pumice as a catalyst in the ozonation process for removal of humic acids from aqueous solutions. Materials and Methods: The molecular structure and chemical composition of pumice were determined using X-ray fluorescence (XRF and X-ray diffraction (XRD. The catalytic ozonation experiments were performed in a semi-batch reactor and the mass of ozone produced was measured by means of iodometric titration methods. Concentration changes in humic acid were determined using a spectrophotometer, at an absorption wavelength of 254 nm. To evaluate the performance of catalytic ozonation in humic acid removal, effects of different parameters including pH, contact time, pumice dosage, and t-butyl alcohol (TBA were examined. Results: The catalytic ozonation results showed that the use of pumice as a catalyst increased the decomposition of humic acid eight times, and the removal efficiency increased as the pH changed from 4 to 12 and catalyst dosage changed from 0.25 to 10 g/l. The catalytic ozonation with considerable efficiency (90% removed humic acid in less time (10 minutes than the sole ozonation process (SOP. Moreover; the results indicated that the catalytic ozonation process (COP, compared to conventional SOP, was less affected by the radical scavenger. Conclusions: Due to the low cost, easy access, and remarkable performance of pumice as a catalyst, it can be used in conventional sole ozonation processes for removing organic pollutants.

  4. 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)

  5. Isolation of Soil Bacteria Adapted To Degrade Humic Acid-Sorbed Phenanthrene

    Science.gov (United States)

    Vacca, D. J.; Bleam, W. F.; Hickey, W. J.

    2005-01-01

    The goal of these studies was to determine how sorption by humic acids affected the bioavailability of polynuclear aromatic hydrocarbons (PAHs) to PAH-degrading microbes. Micellar solutions of humic acid were used as sorbents, and phenanthrene was used as a model PAH. Enrichments from PAH-contaminated soils established with nonsorbed phenanthrene yielded a total of 25 different isolates representing a diversity of bacterial phylotypes. In contrast, only three strains of Burkholderia spp. and one strain each of Delftia sp. and Sphingomonas sp. were isolated from enrichments with humic acid-sorbed phenanthrene (HASP). Using [14C]phenanthrene as a radiotracer, we verified that only HASP isolates were capable of mineralizing HASP, a phenotype hence termed “competence.” Competence was an all-or-nothing phenotype: noncompetent strains showed no detectable phenanthrene mineralization in HASP cultures, but levels of phenanthrene mineralization effected by competent strains in HASP and NSP cultures were not significantly different. Levels and rates of phenanthrene mineralization exceeded those predicted to be supported solely by the metabolism of phenanthrene in the aqueous phase of HASP cultures. Thus, competent strains were able to directly access phenanthrene sorbed by the humic acids and did not rely on desorption for substrate uptake. To the best of our knowledge, this is the first report of (i) a selective interaction between aerobic bacteria and humic acid molecules and (ii) differential bioavailability to bacteria of PAHs sorbed to a natural biogeopolymer. PMID:16000791

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

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    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.

  7. Variability of humic acid properties depending on their precursor material: a study of peat profiles

    Science.gov (United States)

    Klavins, Maris; Purmalis, Oskars

    2015-04-01

    Analysis of variation of peat composition, presence of trace elements in the peat and HSs within peat profiles can give information on the character of transformation of organic matter, important for C biogeochemical cycling, but also about impacts of climate change and human activities. In peat the transformation and decay process of living organic matter (humification) is retarded by the acidic and anaerobic environment, but at the same time the peat can provide information on environmental and paleo-environmental conditions of the past. The aim of the present study is to analyze the elemental and functional composition, spectral characteristics of humic acids isolated from a well characterized raised bog peat profiles to evaluate the impact of the character of humification processes on the peat HA properties. A comparative and complex characterization of humic acids (HAs) isolated from peat profiles of different origin in Latvia was carried out. Elemental and functional analysis of the isolated HAs was done, their acidity and molecular weights estimated. Spectral characterization included UV-Vis, IR, and electron spin resonance and fluorescence spectra. Structural characterization of HAs was by both 1H and 13C nuclear magnetic resonance spectra. Comparison of position of studied humic acids in the Van Krevelen graph was done, thus locating them in the biogeochemical transformation processes of organic matter. Properties of HAs isolated from the Latvian peat were compared with HA from other sources (soil, water, coal and synthetic humic substances). Major properties of peat HAs depended on their origin, indicating the importance of humification processes. HAs isolated from peat of more recent origin were more similar to soil HAs, but from older sources there was a greater degree of humification. Changes of surface tension of solutions of humic acids stress the differences in aggregation character - ability to form supramacromolecular complexes of humic substances

  8. Spectroscopic studies of humic acids from subsurface sediment samples collected across the Aegean Sea

    Directory of Open Access Journals (Sweden)

    F. SAKELLARIADOU

    2006-12-01

    Full Text Available Natural humic acids are biogenic, structurally complex and heterogeneous, refractory, acidic, yellow-to black-coloured organic polyelectrolytes of relatively high molecular weight. They occur in all soils, sediments, fresh waters, and seawaters. Humic acids represent the largest portion of nonliving soil organic matter. In the present paper, humic substances were isolated from marine subsurface sediment samples collected across the Aegean sea (in Greece and especially from a marine area extending northwards of the Samothraki plateau towards the north-eastern part of the island of Crete. In a following step, humic preparations were studied using infrared and fluorescence spectroscopy (emission, excitation and synchronous-scan excitation spectra were obtained. The infrared spectra suggested functional chemical groups such as as OH-, C-H aliphatic, C=C, C=O/COO-, salts of carboxylic acids, and also, in some cases, silicate anions or C-O from alcohols, esters and ethers. Fluorescence emission, excitation and synchronous scan excitation provided some valuable information concerning a probable origin (marine and/or terrestrial for the isolated humics.

  9. Kinetics of rapid covalent bond formation of aniline with humic acid: ESR investigations with nitroxide spin labels

    Science.gov (United States)

    Glinka, Kevin; Matthies, Michael; Theiling, Marius; Hideg, Kalman; Steinhoff, Heinz-Jürgen

    2016-04-01

    Sulfonamide antibiotics used in livestock farming are distributed to farmland by application of slurry as fertilizer. Previous work suggests rapid covalent binding of the aniline moiety to humic acids found in soil. In the current work, kinetics of this binding were measured in X-band EPR spectroscopy by incubating Leonardite humic acid (LHA) with a paramagnetic aniline spin label (anilino-NO (2,5,5-Trimethyl-2-(3-aminophenyl)pyrrolidin-1-oxyl)). Binding was detected by a pronounced broadening of the spectral lines after incubation of LHA with anilino-NO. The time evolution of the amplitude of this feature was used for determining the reaction kinetics. Single- and double-exponential models were fitted to the data obtained for modelling one or two first-order reactions. Reaction rates of 0.16 min-1 and 0.012 min-1, were found respectively. Addition of laccase peroxidase did not change the kinetics but significantly enhanced the reacting fraction of anilino-NO. This EPR-based method provides a technically simple and effective method for following rapid binding processes of a xenobiotic substance to humic acids.

  10. Identification of 6-aminochrysene photoproducts and study of the effect of a humic acid and riboflavin on its photolysis

    Science.gov (United States)

    Zeng, Kui; Hwang, Huey-min; Zhang, Yi; Yu, Hongtao

    2013-01-01

    The effect of the photosensitizer riboflavin (0, 10, 25, 50, 100 μM) and a river humic acid (0, 20, 40, 80 ppm) on the photolysis of 6-aminochrysene (6AC) in 10 mM PBS solution (pH 7.0) was studied. The presence of riboflavin significantly enhanced photolysis rate of 6AC. The photo-transformation half-life of 6AC was 1 min or 36 min respectively in the presence or absence of riboflavin. The humic acid inhibited the photo-transformation rate of 6AC. The photo-transformation half-lives of 6AC were 37, 56, 92 min at 20, 40, 80 ppm humic acid, respectively. By using LC-MS, the main 6AC photoproduct identified was 5,6-chrysene-quinone along with some minor products. Both 6AC and 5,6-chrysene-quinone exhibited photoinduced cytotoxicity. A photochemical transformation pathway for 6AC was derived. PMID:14644571

  11. 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.

  12. Effect of humic acids with different characteristics on fermentative short-chain fatty acids production from waste activated sludge.

    Science.gov (United States)

    Liu, Kun; Chen, Yinguang; Xiao, Naidong; Zheng, Xiong; Li, Mu

    2015-04-21

    Recently, the use of waste activated sludge to bioproduce short-chain fatty acids (SCFA) has attracted much attention as the sludge-derived SCFA can be used as a preferred carbon source to drive biological nutrient removal or biopolymer (polyhydroxyalkanoates) synthesis. Although large number of humic acid (HA) has been reported in sludge, the influence of HA on SCFA production has never been documented. This study investigated the effects on sludge-derived SCFA production of two commercially available humic acids (referred to as SHHA and SAHA purchased respectively from Shanghai Reagent Company and Sigma-Aldrich) that differ in chemical structure, hydrophobicity, surfactant properties, and degree of aromaticity. It was found that SHHA remarkably enhanced SCFA production (1.7-3.5 folds), while SAHA had no obvious effect. Mechanisms study revealed that all four steps (solubilization, hydrolysis, acidification, and methanogenesis) involved in sludge fermentation were unaffected by SAHA. However, SHHA remarkably improved the solubilization of sludge protein and carbohydrate and the activity of hydrolysis enzymes (protease and α-glucosidase) owing to its greater hydrophobicity and protection of enzyme activity. SHHA also enhanced the acidification step by accelerating the bioreactions of glyceradehyde-3P → d-glycerate 1,3-diphosphate, and pyruvate → acetyl-CoA due to its abundant quinone groups which served as electron acceptor. Further investigation showed that SHHA negatively influenced the activity of acetoclastic methanogens for its competition for electrons and inhibition on the reaction of acetyl-CoA → 5-methyl-THMPT, which caused less SCFA being consumed. All these observations were in correspondence with SHHA significantly enhancing the production of sludge derived SCFA.

  13. Influence of ionic strength and pH on the limitation of latex microsphere deposition sites on iron-oxide coated sand by humic acid

    Energy Technology Data Exchange (ETDEWEB)

    Yang, X. [School of Planning, Architecture and Civil Engineering, Queen' s University Belfast, David Keir Building, Stranmillis Road, Belfast BT9 5AG, N. Ireland (United Kingdom); Flynn, R., E-mail: r.flynn@qub.ac.uk [School of Planning, Architecture and Civil Engineering, Queen' s University Belfast, David Keir Building, Stranmillis Road, Belfast BT9 5AG, N. Ireland (United Kingdom); Kammer, F. von der, E-mail: frank.von.der.kammer@univie.ac.at [Department of Environmental Geosciences, University of Vienna, Althanstrasse 14, 1090 Vienna (Austria); Hofmann, T. [Department of Environmental Geosciences, University of Vienna, Althanstrasse 14, 1090 Vienna (Austria)

    2011-07-15

    This study, for the first time, investigates and quantifies the influence of slight changes in solution pH and ionic strength (IS) on colloidal microsphere deposition site coverage by Suwannee River Humic Acid (SRHA) in a column matrix packed with saturated iron-oxide coated sand. Triple pulse experimental (TPE) results show adsorbed SRHA enhances microsphere mobility more at higher pH and lower IS and covers more sites than at higher IS and lower pH. Random sequential adsorption (RSA) modelling of experimental data suggests 1 {mu}g of adsorbed SRHA occupied 9.28 {+-} 0.03 x 10{sup 9} sites at pH7.6 and IS of 1.6 mMol but covered 2.75 {+-} 0.2 x 10{sup 9} sites at pH6.3 and IS of 20 mMol. Experimental responses are suspected to arise from molecular conformation changes whereby SRHA extends more at higher pH and lower ionic strength but is more compact at lower pH and higher IS. Results suggest effects of pH and IS on regulating SRHA conformation were additive. - Highlights: > We quantified the coupled role of pH and IS and humic acid on colloid deposition. > Humic acid enhances microsphere mobility more at higher pH and lower IS. > pH and IS may control the behaviour of humic acid by regulating its conformation. > The effect of pH and IS on regulating humic acid conformation is additive. - This paper quantifies the impact of pH and ionic strength on the transient deposition behaviour of colloids in porous medium in the presence of humic acid.

  14. Neutralization of the antimicrobial effect of glyphosate by humic acid in vitro.

    Science.gov (United States)

    Shehata, Awad A; Kühnert, Manfred; Haufe, Svent; Krüger, Monika

    2014-06-01

    In the present study, the neutralization ability of the antimicrobial effect of glyphosate by different humic acids was investigated. The minimal inhibitory concentrations of glyphosate for different bacteria such as Bacillus badius, Bifidobacterium adolescentis, Escherichia coli, E. coli 1917 strain Nissle, Enterococcus faecalis, Enterococcus faecium, Salmonella enteritidis and Salmonella typhimurium were determined in the presence or absence of different concentrations of humic acid (0.25, 0.5 and 1.0 mg mL(-1)). Our findings indicated that humic acids inhibited the antimicrobial effect of glyphosate on different bacteria. This information can help overcome the negative impact of glyphosate residues in feed and water. Copyright © 2013 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

    Zinc oxide (ZnO)-coated zeolite adsorbents were developed by both nitric acid modification and Zn(NO3)2•6H2O functionalization of zeolite. The developed adsorbents were used for the removal of humic acid (HA) from aqueous solutions. The adsorption capacity of the adsorbents at 21...

  16. Identification of intermediates leading to chloroform and C-4 diacids in the chlorination of humic acid

    NARCIS (Netherlands)

    Sinninghe Damsté, J.S.; Leer, E.W.B. de; Erkelens, Corrie; Galan, L.

    1985-01-01

    The chlorination of terrestrial humic acid was studied at pH 7. 2 with varying chlorine to carbon ratios. The principal products are chloroform, di- and trichloroacetic acid, and chlorinated C-4 diacids. At a high chlorine dose many new chlorination products were detected, among them

  17. Effects of oil palm bunch refuse on humic acid content of five soils ...

    African Journals Online (AJOL)

    The effect of the addition of composted oil palm bunch refuse on five different soils supporting palms with respect to the acidic functional groups of the humic acids in the soils was investigated. The composts was added to the soils at different rates. The results showed that there was a highly significant (P =0.001) increase in ...

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

    African Journals Online (AJOL)

    ... yield (15180 kg ha-1), dry herbage yield (3045 kg ha-1) and plant height (61 cm) was obtained from soil 100% fertilizations, while the highest crude protein concentration (13.43%) was obtained from seeds 33% + soil 33% + leaves 33% fertilizations. Key words: Crude protein, fertilization, fulvic acid, humic acid and vetch.

  19. 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.

  20. Effects of Humic Acid and Sunlight on the Generation and Aggregation State of Aqu/C60 Nanoparticles

    Science.gov (United States)

    Aqueous suspensions of nanoscale C60 aggregates (aqu/C60) were produced by stirring in water with Suwanee River Humic Acid (humic acid) and water from Call’s Creek, a small stream near Athens, GA. Time course experiments were conducted to determine the effects of sunlight and sol...

  1. 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)

  2. A nuclear magnetic resonance study of the dynamics of organofluorine interactions with a dissolved humic acid.

    Science.gov (United States)

    Longstaffe, James G; Courtier-Murias, Denis; Simpson, Andre J

    2016-02-01

    A quantitative understanding of the dynamics of the interactions between organofluorine compounds and humic acids will contribute to an improved understanding of the role that Natural Organic Matter plays as a mediator in the fate, transport and distribution of these contaminants in the environment. Here, Nuclear Magnetic Resonance (NMR) spectroscopy-based diffusion measurements are used to estimate the association dynamics between dissolved humic acid and selected organofluorine compounds: pentafluoroaniline, pentafluorophenol, potassium perfluorooctane sulfonate, and perfluorooctanoic acid. Under the conditions used here, the strength of the association with humic acid increases linearly as temperature decreases for all compounds except for perfluorooctanoic acid, which exhibits divergent behavior with a non-linear decrease in the extent of interaction as temperature decreases. A general interaction mechanism controlled largely by desolvation effects is suggested for all compounds examined here except for perfluorooctanoic acid, which exhibits a specific mode of interaction consistent with a proteinaceous binding site. Reverse Heteronuclear Saturation Transfer Difference NMR is used to confirm the identity and nature of the humic acid binding sites. Copyright © 2015 Elsevier Ltd. All rights reserved.

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

    OpenAIRE

    Bożena Dębska; Magdalena Banach-Szott; Ewa Rosa

    2014-01-01

    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 ...

  4. Double-walled carbon nanotubes suspending by natural active substances (saponins and humic acids

    Directory of Open Access Journals (Sweden)

    Zafour-Hadj-Ziane A.

    2013-09-01

    Full Text Available Carbon nanotubes (CNTs discovered over the past fifteen years are very interesting materials because of their structural, mechanical, chemical and electronic properties. However, their poor dispersion after synthesis constitutes a real obstacle to their use in varied fields. To respond to a topical issue, we proposed a new concept based on the use of natural active substances such a saponins; biosurfactant extracted from the tree Sapindus Mukorossiand humic acids. The results showed that for a concentration of 1.5 mg/l of saponin and 5 mg/l of humic acids, the stable suspensions were obtained; the zeta potential measurements have justified these results.

  5. Coagulation of some humic acid solutions by Moringa oleifera lam seeds: effect on chlorine requirement

    Directory of Open Access Journals (Sweden)

    L.M. Bawa

    2001-12-01

    Full Text Available Experiments were carried out to study humic acid solutions and surface waters coagulation by Moringa oleifera Lam seeds aqueous extract. High amounts of such extract (up to 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. The treatment of water with low turbidity (Moringa oleifera Lam seeds extract released a high amount of organic compounds in treated solutions leading to a high chlorine requirement.

  6. Transport of humic and fulvic acids in relation to metal mobility in a copper-contaminated acid sandy soil

    NARCIS (Netherlands)

    Weng, L.; Fest, E.P.M.J.; Filius, J.; Temminghoff, E.J.M.; Riemsdijk, van W.H.

    2002-01-01

    The transport of inorganic and organic pollutants in water and soil can be strongly influenced by the mobility of natural dissolved organic matter (DOM). In this paper, the transport of a humic acid (HA) and a fulvic acid (FA) in a copper-contaminated acid sandy soil was studied. The data showed

  7. Effects of Applying Humic Acids and Bio-fertilizer on the Qualities and Yields of Strawberry and Soil Agrochemical Characters

    Directory of Open Access Journals (Sweden)

    LIU Ji-pei

    2015-02-01

    Full Text Available A greenhouse experiment was conducted to study the effect of humic acids and bio-fertilizer on the qualities, yields of strawberry and soil agrochemical characters. Humic acids and bio-fertilizer were applied based on the requirement of the normal growth of strawberry. Four treatments were plotted: control(conventional treatment, dressing humic acid, topdressing bio-fertilizer, dressing humic acid+bio-fer-tilizer. Each treatment was repeated three times and randomly arranged. Results showed that application of bio-fertilization, humic acid, hu-mic acid+bio-fertilization could significantly improve the growing of the strawberry, average weight of strawberry during full burning period increased by 8.85%, 14.12% and 16.23%, respectively; Incidence of powdery mildew, gray mold and rot disease of strawberry was signifi-cantly reduced. Yield of strawberry was also improved by 7.70%, 10.80% and 14.7% respectively, compared with the control treatment. The results also showed that application of humic acid+bio-fertilization could significantly increase the protein, vitamin C and soluble sugar con-tent while reduce free acid of strawberry. Soil organic matter content was significantly improved by 0.13, 1.51 g·kg-1 and 1.69 g·kg-1 respec-tively than control when bio-fertilization, humic acid, humic acid+bio-fertilizer were applied. In summary, humic acid and bio-fertilization had a positive impact on the growth of strawberry. Combined application of those two kinds of fertilizer would show the best agricultural effect.

  8. Removal of arsenate with hydrous ferric oxide coprecipitation: effect of humic acid.

    Science.gov (United States)

    Du, Jingjing; Jing, Chuanyong; Duan, Jinming; Zhang, Yongli; Hu, Shan

    2014-02-01

    Insights from the adverse effect of humic acid (HA) on arsenate removal with hydrous ferric oxide (HFO) coprecipitation can further our understanding of the fate of As(V) in water treatment process. The motivation of our study is to explore the competitive adsorption mechanisms of humic acid and As(V) on HFO on the molecular scale. Multiple complementary techniques were used including macroscopic adsorption experiments, surface enhanced Raman scattering (SERS), extended X-ray absorption fine structure (EXAFS) spectroscopy, flow-cell attenuated total reflectance Fourier transform infrared (ATR-FTIR) measurement, and charge distribution multisite complexation (CD-MUSIC) modeling. The As(V) removal efficiency was reduced from over 95% to about 10% with the increasing HA concentration to 25 times of As(V) mass concentration. The SERS analysis excluded the HA-As(V) complex formation. The EXAFS results indicate that As(V) formed bidentate binuclear surface complexes in the presence of HA as evidenced by an As-Fe distance of 3.26-3.31 angstroms. The in situ ATR-FTIR measurements show that As(V) replaces surface hydroxyl groups and forms innersphere complex. High concentrations of HA may physically block the surface sites and inhibit the As(V) access. The adsorption of As(V) and HA decreased the point of zero charge of HFO from 7.8 to 5.8 and 6.3, respectively. The CD-MUSIC model described the zeta potential curves and adsorption edges of As(V) and HA reasonably well.

  9. Aggregation and disaggregation of ZnO nanoparticles: influence of pH and adsorption of Suwannee River humic acid.

    Science.gov (United States)

    Mohd Omar, Fatehah; Abdul Aziz, Hamidi; Stoll, Serge

    2014-01-15

    The surface charge and average size of manufactured ZnO nanoparticles (NPs) were studied as a function of pH to understand the aggregation behavior and importance of the electrostatic interactions in solution. The interactions between ZnO and Suwannee River humic acid (SRHA) were then investigated under a range of environmentally relevant conditions with the ZnO nanoparticles pHPZC as the point of reference. The anionic charges carried by aquatic humic substances were found to play a major role in the aggregation and disaggregation of ZnO nanoparticles. At low concentrations of SRHA (<0.05 mg/L) and below the pHPZC, anionic SRHA was rapidly adsorbed onto the positively charged ZnO NPs hence promoting aggregation. With similar SHRA concentrations, at pHPZC, SRHA was able to control the suspension behavior of the ZnO and promote partial disaggregation in small volumes. This was more distinguishable when the pH was greater than pHPZC as SRHA formed a surface coating on the ZnO nanoparticles and enhanced stability via electrostatic and steric interactions. In most cases, the NP coating by SRHA induced disaggregation behavior in the ZnO nanoparticles and decreased the aggregate size in parallel to increasing SRHA concentrations. Results also suggest that environmental aquatic concentration ranges of humic acids largely modify the stability of aggregated or dispersed ZnO nanoparticles. © 2013.

  10. Feasibility of humic substances removal by enhanced coagulation process in surface water

    Directory of Open Access Journals (Sweden)

    Mohammad Mehdi Amin

    2012-01-01

    Full Text Available Aims: This study evaluates the effectiveness of polyaluminium chloride (PAClas a coagulant for enhanced coagulation (EC of humic substances (HS in surface water. Materials and Methods: Dissolved organic carbon (DOC, ultraviolet absorbance (UV 254 , specific ultraviolet absorbance (SUVA, and humic acid (HA were determined as the HS indices. HS was extracted by Amberlit XAD-7HP from water and HA was analyzed by high performance liquid chromatography (HPLC. The HS index was determined in raw water and after clarification and filtration in all seasons. The efficiency of PACl for removal of HS, both in the jar test and pilot scale were determined. Results: The average extraction efficiency for XAD-7HP was 77%, and the HA concentration was determined in all seasons ranging from 0.15 to 0.29 mg/ L in raw water. The DOC in raw water was in the range of 1.5 to 4mg/L, in all seasons. The average removal efficiency of PACl for EC was 52% for HA in the pilot scale. Also the average removal efficiencies of PACl EC for DOC and UV 254 were 43 and 57% on the pilot scale and 38 and 41% in the jar test, respectively. The optimum pH for removal of HS was 7.5 ± 0.2 and the optimum PACl dose was 12 ± 0.5 mg/L. Conclusions: After EC, the aluminum concentration was lower than the maximum concentration level (MCL of aluminum in drinking water ( 8.5 was very poor for the HS index and turbidity.

  11. 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

  12. Decolorization of azo dyes by Shewanella oneidensis MR-1 in the presence of humic acids.

    Science.gov (United States)

    Liu, Guangfei; Zhou, Jiti; Wang, Jing; Wang, Xiujuan; Jin, Ruofei; Lv, Hong

    2011-07-01

    The effects of humic acid (HA) on azo dye decolorization by Shewanella oneidensis MR-1 were studied. It was found that HA species isolated from different sources could all accelerate the decolorization of Acid Red 27 (AR27). Anoxic and anaerobic conditions were required for the enhancement of azo dye decolorization by HA. In the presence of 50 mg DOC L⁻¹ Aldrich HA, 15-29% increases in decolorization efficiencies of azo dyes with different structures were achieved in 11 h. The enhancing effects increased with the increase of HA concentrations ranging from 25 to 150 mg DOC L⁻¹, and the decolorization rates were directly proportional to the HA concentrations when they were below 100 mg DOC L⁻¹. Lactate and formate were good electron donors for AR27 decolorization in the presence of HA. Both nitrate (0.1-3.0 mM) and nitrite (0.3-1.2 mM) inhibited AR27 decolorization in the presence of HA, and negligible decolorization was observed before their removal. Soluble FeCl₃ could accelerate the decolorization process in the presence of HA, whereas insoluble hematite could not. These findings may affect the understanding of bioremediation of azo dye-polluted environments and help improve the treatment of azo dye wastewaters.

  13. 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.

  14. Partitioning of humic acids between aqueous solution and hydrogel. 2. Impact of physicochemical conditions

    NARCIS (Netherlands)

    Zielinska, K.; Town, R.M.; Yasadi, K.; Leeuwen, van H.P.

    2015-01-01

    The effects of the physicochemical features of aqueous medium on the mode of partitioning of humic acids (HAs) into a model biomimetic gel (alginate) and a synthetic polyacrylamide gel (PAAm) were explored. Experiments were performed under conditions of different pH and ionic strength as well as in

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

    African Journals Online (AJOL)

    Daniel

    rice seedlings from Cd and As (arsenic) (Panda et al.,. 2011; Singh et al., 2009). These studies strongly suggest that exogenous NO can protect plants from the harmful impacts of toxic heavy metals concentrations. The aim of this research was to evaluate the effect of Humic Acid and Sodium Nitroprusside on diminishment ...

  17. 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

  18. Coagulant properties of Moringa oleifera protein preparations: application to humic acid removal.

    Science.gov (United States)

    Santos, Andréa F S; Paiva, Patrícia M G; Teixeira, José A C; Brito, António G; Coelho, Luana C B B; Nogueira, Regina

    2012-01-01

    This work aimed to characterize the coagulant properties of protein preparations from Moringa oleifera seeds in the removal of humic acids from water. Three distinct preparations were assayed, namely extract (seeds homogenized with 0.15 M NaCl), fraction (extract precipitated with 60% w/v ammonium sulphate) and cMoL (protein purified with guar gel column chromatography). The extract showed the highest coagulant activity in a protein concentration between 1 mg/L and 180 mg/L at pH 7.0. The zeta potential of the extract (-10 mV to -15 mV) was less negative than that of the humic acid (-41 mV to -42 mV) in a pH range between 5.0 and 8.0; thus, the mechanism that might be involved in this coagulation activity is adsorption and neutralization of charges. Reduction of total organic carbon (TOC) and dissolved organic carbon (DOC) was observed in water samples containing 9 mg/L carbon as humic acid when treated with 1 mg/L of the extract. A decrease in colour and in the aromatic content of the treated water was also observed. These results suggested that the extract from M. oleifera seeds in a low concentration (1 mg/L) can be an interesting natural alternative for removing humic acid from water in developing countries. The extract dose determined in the present study does not impart odour or colour to the treated water.

  19. 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.

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

    African Journals Online (AJOL)

    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 following five dietary treatments ...

  1. Effect of Humic Acid and Sunlight on the Generation of aqu/C60

    Science.gov (United States)

    Little is known about the effect of sunlight and natural organic matter, such as humic acid, on the aqueous suspension of fullerene C60. This knowledge gap limits our ability to determine the environmental impact of potential environmental releases of these materials. Aqueous sus...

  2. 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

  3. DYNAMIC CONDUCTIVITY MEASUREMENTS IN HUMIC AND FULVIC ACID SOLUTIONS. (R828158)

    Science.gov (United States)

    Conductivity changes of dilute aqueous humic and fulvic acids solutions were monitored after the addition of small quantities of Cu, Cd, Pb, and Zn. The solutions were stirred at a constant and reproducible rate, and measurements proceeded until stable conductivities were atta...

  4. 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...

  5. Chitosan, the Marine Functional Food, Is a Potent Adsorbent of Humic Acid

    Directory of Open Access Journals (Sweden)

    Chao-Lin Liu

    2011-11-01

    Full Text Available Chitosan is prepared by the deacetylation of chitin, the second-most abundant biopolymer in nature, and has applicability in the removal of dyes, heavy metals and radioactive waste for pollution control. In weight-reduction remedies, chitosan is used to form hydrogels with lipids and to depress the intestinal absorption of lipids. In this study, an experimental method was implemented to simulate the effect of chitosan on the adsorption of humic acid in the gastrointestinal tract. The adsorption capacity of chitosan was measured by its adsorption isotherm and analyzed using the Langmuir equation. The results showed that 3.3 grams of humic acid was absorbed by 1 gram of chitosan. The adsorption capacity of chitosan was much greater than that of chitin, diethylaminoethyl-cellulose or activated charcoal. Cellulose and carboxymethyl-cellulose, a cellulose derivative with a negative charge, could not adsorb humic acid in the gastrointestinal tract. This result suggests that chitosan entraps humic acid because of its positive charge.

  6. 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 ...

  7. Prophylactic effects of humic acid AND#8211; glucan combination against experimental liver injury

    Directory of Open Access Journals (Sweden)

    Vaclav Vetvicka

    2015-09-01

    Full Text Available Aim: Despite intensive research, liver diseases represent a significant health problem and current medicine does not offer a substance able to significantly inhibit the hepatotoxicity leading to various stages of liver disease. Based on our previously published studies showing the protective effects of a glucan-humic acid combination, we focused on the hypothesis that combination of these two natural molecules can offer prophylactic protection against experimentally induced hepatotoxicity. Methods: lipopolysaccharide (LPS, carbon tetrachloride (CCl4 and ethanol were used to experimentally damage the liver. Levels of aspartate aminotransferase (AST, alanine transaminase (ALT, alkaline phosphatase (ALP, glutathione (GSH, superoxide dismutase (SOD and malondialdehyde (MDA, known to correspond to the liver damage, were assayed. Results: Using three different hepatotoxins, we found that in all cases, some samples of humic acid and most of all the glucan-humic acid combination, offer strong protection against liver damage. Conclusion: glucan-humic acid combination is a promising agent for use in liver protection. [J Intercult Ethnopharmacol 2015; 4(3.000: 249-255

  8. DGT/DET Gel partition features of humic acid/metal species

    NARCIS (Netherlands)

    Veeken, van der P.L.R.; Leeuwen, van H.P.

    2010-01-01

    Gel layer based sensors are increasingly employed for dynamic trace metal speciation analysis in aquatic and soil media, in which humic and fulvic acid species are generally known to be relevant. In DGT (diffusive gradient in thin film), polyacrylamide hydrogels are commonly used for the diffusive

  9. Role of the humic acid for sorption of radionuclides by synthesized titania

    Energy Technology Data Exchange (ETDEWEB)

    Singh, B.K.; Tomar, Radha [Jiwaji Univ., Gwalior (India). School of Studies in Chemistry; Kumar, Sumit; Kar, A.S.; Tomar, B.S. [Bhabha Atomic Reseach Centre, Mumbai (India). Radio Analytical Chemistry Div.; Ramanathan, S. [Bhabha Atomic Reseach Centre, Mumbai (India). Material Science Div.; Manchanda, V.K. [Bhabha Atomic Reseach Centre, Mumbai (India). Radiochemistry Div.

    2014-04-01

    Present work reports on synthesis, characterization and application of titania powder (anatase) for sorption of {sup 137}Cs (monovalent), {sup 133}Ba (divalent) and {sup 154}Eu (trivalent) radionuclides in the presence and absence of humic acid (Aldrich). In order to obtain a detailed sorption behavior of all the three aforementioned radionuclides, a series of experiments were conducted with respect to effect of pH, humic acid (HA), and concentration of radionuclides. Sorption studies of {sup 137}Cs, {sup 133}Ba and {sup 154}Eu onto synthesized titania have been carried out over a wide range of pH scale varying from 3 to 11 in the presence and absence of Aldrich Humic acid (2 mg/L). Sorption of all the three radionuclides rises sharply with the pH of the suspension with saturation value of ∝ 70%, 80% and 85% respectively for monovalent, bivalent and trivalent radionuclides. Humic acid could not make any influence for sorption of {sup 137}Cs, but significantly altered with respect to {sup 133}Ba and {sup 154}Eu sorption. The sorption data at various concentrations were fitted with Freundlich isotherm model. (orig.)

  10. Removal of dissolved humic acid from water by photocatalytic oxidation using a silver orthophosphate semiconductor

    Energy Technology Data Exchange (ETDEWEB)

    Hatakeyama, Keisuke, E-mail: hatakeyamak@pref.tottori.jp [Tottori Prefectural Institute of Public Health and Environmental Science, 526-1, Minamidani, Yurihama-cho, Tottori 682-0704 (Japan); Okuda, Masukazu; Kuki, Takahiro [Tottori Prefectural Institute of Public Health and Environmental Science, 526-1, Minamidani, Yurihama-cho, Tottori 682-0704 (Japan); Esaka, Takao [Department of Chemistry and Biotechnology, Graduate School of Engineering, Tottori University, Minami 4-101, Koyama-cho, Tottori 680-8552 (Japan)

    2012-12-15

    Graphical abstract: Display Omitted Highlights: ► The photocatalytic property of a silver orthophosphate (Ag{sub 3}PO{sub 4}) was investigated for humic acid degradation. ► The Ag{sub 3}PO{sub 4} shows high photocatalytic activity under visible light. ► The photocatalytic activity was greatly improved by employing the precipitation method. -- Abstract: In order to remove dissolved organic matter such as humic acid from water, a silver orthophosphate (Ag{sub 3}PO{sub 4}) was newly employed as a heterogeneous photocatalyst. Here, Ag{sub 3}PO{sub 4} was prepared by simple ion-exchange and precipitation methods, and the physico-chemical properties were characterized by X-ray diffraction, ultraviolet–visible diffuse reflectance spectroscopy, scanning electron microscopy, particle distribution measurements and Brunauer–Emmett–Teller (BET) analysis. The degradation of humic acid was faster over Ag{sub 3}PO{sub 4} catalyst than over conventional TiO{sub 2} (P-25). The total photocatalytic properties were improved by employing not an ion-exchange method but a precipitation method; humic acid degradation was performed with a removal ratio of dissolved organic carbon of 75% under visible light (λ = 451 nm) for 2-h irradiation.

  11. Regularities of extracting humic acids from soils using sodium pyrophosphate solutions

    Science.gov (United States)

    Bakina, L. G.; Drichko, V. F.; Orlova, N. E.

    2017-02-01

    Regularities of extracting humic acids from different soil types (soddy-podzolic soil, gray forest soil, and all chernozem subtypes) with sodium pyrophosphate solutions at different pH values (from 5 to 13) have been studied. It is found that, regardless of soil type, the process occurs in two stages through the dissociation of carboxylic groups and phenolic hydroxyls, each of which can be described by a logistic function. Parameters of the logistic equations approximating the extraction of humic acids from soils at different pH values are independent of the content and composition of humus in soils. Changes in the optical density of humic acids extracted from soils using sodium pyrophosphate solutions with different pH values are described in the first approximation by the Gaussian function. The optically densest humic acids are extracted using sodium pyrophosphate solutions at pH 10. Therefore, it is proposed to use an extract with pH 10 for the characterization of organic matter with the maximum possible degree of humification in the given soil.

  12. Nickel(II) and copper(II) complexes with humic acid anions and their derivatives

    Energy Technology Data Exchange (ETDEWEB)

    Ryabova, I.N. [Kazakh Academy of Science, Karaganda (Kazakhstan)

    2008-01-15

    Complexation of Ni(II) and Cu(II) in aqueous solutions with anions of humic acids, extracted from naturally oxidized coal, and with their hydroxymethyl derivatives is studied spectrophotometrically and potentiometrically. The complexation stoichiometry and the stability constants of the complexes are determined.

  13. Chemical properties of humic and fulvic acid products and their ores of origin

    Science.gov (United States)

    Commercial products consisting of humic and fulvic acids are thought to boost plant growth and economic yield in cropland agriculture. The specific mechanism for their benefit is unknown, in part because little information is available on the chemical nature of these products. We examined the chemic...

  14. Influence of humic fulvic acid on the sorption behaviour of Eu(III) on natural hematite

    Energy Technology Data Exchange (ETDEWEB)

    Rabung, T. [Universitaet des Saarlandes, Saarbruecken (Germany). Anorganische und Analytische Chemie und Radiochemie]|[Forschungszentrum Karlsruhe GmbH Technik und Umwelt (Germany). Inst. fuer Nukleare Entsorgungstechnik; Geckeis, H.; Kim, J.I. [Forschungszentrum Karlsruhe GmbH Technik und Umwelt (Germany). Inst. fuer Nukleare Entsorgungstechnik; Beck, H.P. [Universitaet des Saarlandes, Saarbruecken (Germany). Anorganische und Analytische Chemie und Radiochemie

    1999-04-01

    The solid-water interface reaction is investigated for the sorption of the Eu(III) ion, as a trivalent actinide homologue, onto well-characterized natural hematite at pH{<=}6 in 0.1 M NaClO{sub 4} in the presence of humic and fulvic acid (HA/FA). (orig.)

  15. Dispersion state and humic acids concentration-dependent sorption of pyrene to carbon nanotubes

    NARCIS (Netherlands)

    Zhang, X.; Kah, M.; Jonker, M.T.O.; Hofmann, T.

    2012-01-01

    Sonication and humic acids (HA) are known to disperse carbon nanotube (CNT) suspensions, but potential effects on sorption of chemicals to CNTs remain poorly understood. We applied a passive sampling method to investigate the influence of dispersion/aggregation on sorption of pyrene to CNTs.

  16. 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 ...

  17. Effect of Humic Acid on Soil Chemical and Physical Characteristics of Embankment

    Directory of Open Access Journals (Sweden)

    Ali Munawar

    2016-01-01

    Full Text Available The effectiveness of the treatment of pathogens disease in fish using chemicals is very limited because of the stress of toxic ions. A treatment of humic acid of 50-90 mg /L on a farmland has been able to reduce illness and death compared to a mixture of formaldehyde and blue-green methylene. Humic acid is suspected to be able to increase yield, through improved conditions and resistance to diseases, health, and cultural vitality, either by itself or combined with cation species toxic. Humic acid can balance the soil cation so that the soil pH reached 7-8, through a chelate of Al, Fe, Ca or exchanged with NH4, Na and K. Humic acids were extracted from compost plants with a weak base of 0.1 N NaOH and precipitated at pH 2. The concentration of AH 0- 400 ml was applied to three soil types with an area of 0.12 m2 and 15 cm thickness. The results showed that the application of 100-200 ml HA/0.12 m2 gave optimum yield in improving the physical-chemical characteristics of the soil embankment. Soil pH reached a value of 7-8, cation exchange to 60% saturated, and soil bulk density was reached in the range of 1.1- 0.97 g / cm3.This condition is suitable for fish or shrimp in the embankment.

  18. 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

  19. 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

  20. 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

  1. 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

  2. The role of natural purified humic acids in modifying mercury accessibility in water and soil

    Energy Technology Data Exchange (ETDEWEB)

    Cattani, I.; Zhang, H.; Beone, G.M.; Del Re, A.A.M.; Boccelli, R.; Trevisan, M. [University of Cattolica Sacro Cuore, Piacenza (Italy)

    2009-03-15

    We investigated the influence of different humic acids (HAs, extracted from lignite, compost, and forest soil) on mercury mobility and availability both in a model solution and in soil samples from a mercury-polluted region. The technique of diffusive gradients in thin-films (DGT), which is capable of measuring: (i) free metal in solution: (ii) dissociated metal complexes previously mobilized by HA; (iii) mobilized metal-HA complexes that liberate metals by dissociation or by exchange reaction between the metal-HA complexes and the chelating groups on the resin-gel, was used in solutions and soils. The DGT measurements in solution, together with ultrafiltration, allowed estimation of the lability of Hg-HA complexes. Ultrafiltration results were also compared with predictions made by the windermere humic-aqueous model (WHAM). According to both these different approaches, Hg{sup 2+} resulted nearly 100% complexed by HAs, whereas results from ultrafiltration showed that 32 to 72% of the CH{sub 4}Hg{sup +} was bound to the HAs, with higher values for compost and lower values for forest and Aldrich HA. The DGT-measured mercury in soils was below 0.20 {mu}g L{sup -1}, irrespective of the extent of the contamination. Addition of HA increased the concentration of DGT-measured mercury in soil solution up to 100-fold in the contaminated soil and up to 30-fold in the control soil. The level of the increase also depended on the HA. The smallest increase (about 10 times) was found for lignite HA in both control and contaminated soils. The addition of forest HA gave the largest increases in DGT-measured mercury, in particular for the contaminated soil. Overall, the results demonstrated that DGT can be used for estimating the lability of mercury complexes in solution and for verifying enhanced mercury mobility when HA is added to contaminated soils.

  3. Phenanthrene binding by humic acid-protein complexes as studied by passive dosing technique.

    Science.gov (United States)

    Zhao, Jian; Wang, Zhenyu; Ghosh, Saikat; Xing, Baoshan

    2014-01-01

    This work investigated the binding behavior of phenanthrene by humic acids (HA-2 and HA-5), proteins (bovine serum albumin (BSA)), lysozyme and pepsin), and their complexes using a passive dosing technique. All sorption isotherms were fitted well with Freundlich model and the binding capability followed an order of HA-5 > HA-2 > BSA > pepsin > lysozyme. In NaCl solution, phenanthrene binding to HA-BSA complexes was much higher than the sum of binding to individual HA and BSA, while there was no enhancement for HA-pepsin. Positively charged lysozyme slightly lowered phenanthrene binding on both HAs due to strong aggregation of HA-lysozyme complexes, leading to reduction in the number of binding sites. The binding enhancement by HA-BSA was observed under all tested ion species and ionic strengths. This enhancement can be explained by unfolding of protein, reduction of aggregate size and formation of HA-BSA complexes with favorable conformations for binding phenanthrene. Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. 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.

  5. ADSORPTION OF Am-241, Cs-137 AND Sr-90 RADIONUCLIDES WITH BENTONITE-HUMIC ACID IMMOBILIZED YIELD

    Directory of Open Access Journals (Sweden)

    Kris Tri Basuki

    2010-06-01

    Full Text Available Adsorption of Am-241, Cs-137 and Sr-90 radionuclides to bentonite-humic acid immobilized yield have been done. The aims of this study are (1 making of adsorbent materials from resulted immobilization humic acid into bentonite mineral, and it's characterization with spectroscopy infrared and X-ray diffractometer and (2 adsorption of Am-241, Cs-137 and Sr-90 radionuclides into bentonite mineral as adsorbent at various pH. Experiments showed that result of immobilization of bentonite-humic acid were optimum at 100 g bentonite, 60 g humic acid, 0.1 M NaNO3 ionic strength, and 2.5 pH. At the optimum condition bentonite could be bonded by the functional COOH from humic acid maximum equal to 75.2%. Base on infrared spectroscopy and X-ray diffractometer showed that humic acid can immobilized into bentonite to form of bentonite-humic acid alloy. Application of adsorbent bentonite-humic acid immobilized yield to adsorb radionuclides of Am-241, Cs-137 and of Sr-90, showed that can adsorb at the range of pH 3 until 10. The phenomenon adsorption as species radionuclides was predicted by ";;Visual minteq";; software. By each the feeds of radionuclide 0.001 mMol/L, 0.1 M NaNO3 ionic strength and pH 5 showed that bentonite-humic acid can adsorb radionuclides 98.50-99.1% of Am-241, Cs-137, and Sr-90.   Keywords: immobilisation, adsorption, infra red spectroscopy, X-ray diffractometer

  6. 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.

  7. Partitioning of humic acids between aqueous solution and hydrogel. 3. Microelectrodic dynamic speciation analysis of free and bound humic metal complexes in the gel phase

    NARCIS (Netherlands)

    Yasadi, K.; Pinheiro, J.P.; Zielinska, K.; Town, R.M.; Leeuwen, van H.P.

    2015-01-01

    The hydrogel/water partitioning of the various species in the cadmium(II)/soil humic acid (HA) system is studied for two types of gel, using in situ microelectrodic voltammetry. Under the conditions of this work, with HA particles of ca. 25 and 125 nm radius, the CdHA complex is shown to be close to

  8. 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.

  9. Photolytic and photocatalytic degradation of tetracycline: Effect of humic acid on degradation kinetics and mechanisms.

    Science.gov (United States)

    Li, Si; Hu, Jiangyong

    2016-11-15

    The widespread occurrence of tetracycline (TC) in the aquatic environment poses a potential risk to aquatic ecosystem and human health. In this study, elimination of TC by photolysis and TiO2 photocatalysis were investigated by using mercury-free UVA-LED as an alternative light source. Particular emphasis was given to the effect of humic acid (HA) on the reaction kinetics and mechanisms of TC removal. Photolytic degradation of TC was slightly enhanced by HA due to its photosensitization effect, as evidenced by the increased steady-state concentrations of OH. The most abundant transformation product of TC, which was formed by the attack of OH radical, was enhanced during photolytic degradation. During photocatalytic experiments, HA dramatically inhibited TC loss due to the surface deactivation of TiO2 and OH quenching. The steady-state concentration of OH was dramatically decreased in the presence of HA. Identification of transformation products showed that HA could inhibit the oxidation pathways initiated by OH during photocatalysis of TC. These findings provide further insights into the assessment of photolysis and photocatalysis for antibiotics elimination in natural waters where HA exists ubiquitously. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Adventitious rooting in cuttings of croton and hibiscus in response to indolbutyric acid and humic acid

    Directory of Open Access Journals (Sweden)

    Lílian Estrela Borges Baldotto

    2012-08-01

    Full Text Available Adventitious rooting of ornamental plants can be accelerated by the application of growth regulators, such as auxin. Humic acids, organic matter in soil and organic compounds also have a biostimulant effect. This work evaluated the rooting in cuttings of croton (Codianeum variegatum L. Rumph and hibiscus (Hibiscus rosa-sinensis L in response to the application of different concentrations of indolbutyric acid (IBA and humic acid (HA. The experiment was carried out in a greenhouse. Apical stem cuttings were treated with solutions at concentrations of: 0, 250, 500, 1000, 2000 mg L-1 IBA and 0, 10, 20, 30, 40 mmol L-1 HA carbon isolated from vermicomposting. Forty-five days after the applications, the cuttings were removed from the pots containing carbonized rice hull and the following variables were measured: rooting number, length and width of leaves, fresh and dry matter of root and aerial part and root area. The results were subjected to analysis of variance and the qualitative and quantitative effects of the treatments were compared by contrast and regression, respectively. Regression equations were used to determine the maximum efficiency level of root dry matter according to IBA and HA. Higher accumulation of root dry matter was recorded for the treatments with the doses 579 mg L-1 IBA and 14 mmol L-1 HA and 970 mg L-1 IBA and 50 mmol L-1 HA for root cuttings of croton and hibiscus, respectively. It was found that the application of eiher IBA or HA at the indicated doses accelerates rooting in cuttings of croton and hibiscus and contributes to the formation of vigorous plants.

  11. The Role of Humic Acid in Cobalt Sorption to Soil Minerals

    Science.gov (United States)

    Woodward, Gemma; Peacock, Caroline; Thompson, Olivia; Law, Gareth; Fariña, Alba Otero; Burke, Ian

    2016-04-01

    Batch sorption experiments have been carried out to investigate cobalt sorption to ferrihydrite, kaolinite, and humic acid (HA) as a function of pH; and to ferrihydrite-HA and kaolinite-HA composites at three different total carbon contents. Sorption to the composites was enhanced at low pH values (<7) compared to the pure ferrihydrite and kaolinite systems. For the ferrihydrite-HA composites, there was no significant difference in the amount that sorption was enhanced by for the different composites. However, sorption was dependent on the C content of the kaolinite-HA composites, with more Co sorbed to the composites at higher C concentrations. Changes in Co speciation in the kaolinite and kaolinite-HA composite system was investigated using XAS analysis. EXAFS spectra collected from kaolinite samples at pH 5-6 show a single shell of 6 O backscatters; indicative of Co present in an outer-sphere sorption complex. At pH 7-8, Co-Al(Si) and Co-Co backscatters were also resolved indicating Co present in inner-sphere complexes or as Co(OH)2 surface precipitates. At pH 5-6, EXAFS spectra for Co sorption to pure HA and the kaolinite-HA composite are similar, with Co-carboxyl bonding evident, suggesting that Co is predominantly associated with the HA phase of the composite at low pH. Co sorption to natural humic acid was also studied as a function of pH, and determined in samples after filtration at both 0.22μm and 10kDa. Data from the samples filtered at 10kDa (<˜2nm) represent the best estimate of true sorption behaviour. Co sorption increased with increasing pH, reaching ˜90% at pH 7. The 0.22μm filtered samples showed incomplete sorption above pH 5, indicating that increased solvation of HA at high pH values results in a 1.5-220nm Co-HA phase that is potentially mobile at pH values where high Co sorption would be expected.

  12. A comparative evaluation of metal humic and fulvic acid predictive models

    Energy Technology Data Exchange (ETDEWEB)

    Warwick, P. [Loughborough Univ. of Technology (United Kingdom). Dept. of Chemistry; Hall, T. [Loughborough Univ. of Technology (United Kingdom). Dept. of Chemistry; Read, D. [RM Consultants Ltd., Abingdon (United Kingdom)

    1996-10-01

    Research into the safe disposal of nuclear waste prompted a comparative study of the predictive capabilities and limitations of metal humic and fulvic acid binding models. Three approaches were investigated: (i) A simple ligand mixture approach; (ii) a continuous distribution approach; and (iii) an electrostatic discrete site approach. Appropriate geochemical equilibrium codes, incorporating the models designated, PHREEQESP, MINTEQA2 and PHREEQEV, were applied to three unrelated test problems, (1) Ni interactions with fulvic acid. (2) Eu interactions with fulvic and humic acids and (3) actinide speciation in Mol groundwater. The model predictions were compared with experimental data. Only PHREEQEV provided results in all three test cases. Overall it was concluded that of the approaches tested PHREEQEV currently offers the most advantages for predictive modelling. (orig.)

  13. Plant tolerance to mercury in a contaminated soil is enhanced by the combined effects of humic matter addition and inoculation with arbuscular mycorrhizal fungi.

    Science.gov (United States)

    Cozzolino, V; De Martino, A; Nebbioso, A; Di Meo, V; Salluzzo, A; Piccolo, A

    2016-06-01

    In a greenhouse pot experiment, lettuce plants (Lactuca sativa L.) were grown in a Hg-contaminated sandy soil with and without inoculation with arbuscular mycorrhizal fungi (AMF) (a commercial inoculum containing infective propagules of Rhizophagus irregularis and Funneliformis mosseae) amended with different rates of a humic acid (0, 1, and 2 g kg(-1) of soil), with the objective of verifying the synergistic effects of the two soil treatments on the Hg tolerance of lettuce plants. Our results indicated that the plant biomass was significantly increased by the combined effect of AMF and humic acid treatments. Addition of humic matter to soil boosted the AMF effect on improving the nutritional plant status, enhancing the pigment content in plant leaves, and inhibiting both Hg uptake and Hg translocation from the roots to the shoots. This was attributed not only to the Hg immobilization by stable complexes with HA and with extraradical mycorrhizal mycelium in soil and root surfaces but also to an improved mineral nutrition promoted by AMF. This work indicates that the combined use of AMF and humic acids may become a useful practice in Hg-contaminated soils to reduce Hg toxicity to crops.

  14. 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...

  15. The investigation of humic acid adsorption from aqueous solutions onto modified pumice with hexadecyl trimethyl ammonium bromide

    Directory of Open Access Journals (Sweden)

    Ghorban Asgari

    2013-01-01

    Conclusions: It was understood from the results of this study that adsorption onto modified pumice is efficient in performance and thus affordable technology for the elimination of humic acid from the polluted water supply.

  16. Effect of pH, ionic strength and humic acid on the sorption of uranium(VI) to attapulgite

    Energy Technology Data Exchange (ETDEWEB)

    Niu Zhiwei [Radiochemistry Laboratory, Lanzhou University, Lanzhou 730000, Gansu (China); Fan Qiaohui [Radiochemistry Laboratory, Lanzhou University, Lanzhou 730000, Gansu (China)], E-mail: fanqiaohui@gmail.com; Wang Wenhua; Xu Junzheng [Radiochemistry Laboratory, Lanzhou University, Lanzhou 730000, Gansu (China); Chen Lei [School of Chemical Engineering, Shandong University of Technology, 255049 Zibo, Shandong (China); Wu Wangsuo [Radiochemistry Laboratory, Lanzhou University, Lanzhou 730000, Gansu (China)], E-mail: wuws@lzu.edu.cn

    2009-09-15

    Attapulgite was investigated to remove UO{sub 2}{sup 2+} from aqueous solutions because of its strong sorption capacity. Herein, the attapulgite sample was characterized by Fourier transform infrared spectra (FTIR), X-ray diffraction (XRD) and acid-base titration in detail. Sorption of UO{sub 2}{sup 2+} on attapulgite was strongly dependent on pH values and ionic strength. The presence of humic acid enhanced the sorption of UO{sub 2}{sup 2+} on attapulgite obviously because of the strong complexation of humic acid (HA) with UO{sub 2}{sup 2+} on attapulgite surface. Sorption of UO{sub 2}{sup 2+} on attapulgite was mainly dominated by ion-exchange or outer-sphere complexation at low pH values, and by inner-sphere complexation at high pH values. The results indicated that attapulgite was a suitable material for the preconcentration and solidification of UO{sub 2}{sup 2+} from large volume of solutions because of its negative surface charge and large surface areas.

  17. Environmentally relevant concentration of arsenic trioxide and humic acid promoted tumor progression of human cervical cancer cells: In vivo and in vitro studies.

    Science.gov (United States)

    Tsai, Min-Ling; Yen, Cheng-Chieh; Lu, Fung-Jou; Ting, Hung-Chih; Chang, Horng-Rong

    2016-09-01

    In a previous study, treatment at higher concentrations of arsenic trioxide or co-exposure to arsenic trioxide and humic acid was found to be inhibited cell growth of cervical cancer cells (SiHa cells) by reactive oxygen species generation. However, treatment at lower concentrations slightly increased cell viability. Here, we investigate the enhancement of progression effects of environmentally relevant concentration of humic acid and arsenic trioxide in SiHa cell lines in vitro and in vivo by measuring cell proliferation, migration, invasion, and the carcinogenesis-related protein (MMP-2, MMP-9, and VEGF-A) expressions. SiHa cells treated with low concentrations of humic acid and arsenic trioxide alone or in co-exposure significantly increased reactive oxygen species, glutathione levels, cell proliferation, scratch wound-healing activities, migration abilities, and MMP-2 expression as compared to the untreated control. In vivo the tumor volume of either single drug (humic acid or arsenic trioxide) or combined drug-treated group was significantly larger than that of the control for an additional 45 days after tumor cell injection on the back of NOD/SCID mice. Levels of MMP-2, MMP-9, and VEGF-A, also significantly increased compared to the control. Histopathologic effects of all tumor cells appeared round in cell shape with high mitosis, focal hyperkeratosis and epidermal hyperplasia in the skin, and some tumor growth in the muscle were observed. Our results may indicate that exposure to low concentrations of arsenic trioxide and humic acid is associated with the progression of cervical cancer. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1121-1132, 2016. © 2015 Wiley Periodicals, Inc.

  18. Effects of Humic Acid-based Cation Buffer on Chemical Characteristics of Saline Soil and Growth of Maize

    OpenAIRE

    Mindari, W; N. Aini; Z Kusuma; Syekhfani, S

    2014-01-01

    Humic acid is believed to maintain the stability of the soil reaction, adsorption / fixation / cationic chelate, 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 nutrient uptake of plants. This experiment was aimed to examine the characteristics of the humic acid from compost, coal, and peat and its function in the adsorption of cations (K+ and NH4+), t...

  19. Comparative study of humic acid extract with ammoniacal solutions from coals in inferior rank and from Romanian soil

    Energy Technology Data Exchange (ETDEWEB)

    Chiriac, J.; Barca, F. [Universitatea Politehnica din Bucuresti, Bucharest (Romania)

    2009-04-15

    The paper shows the similitude that exists between humic acids extracted from Rosia (Jiu) and Schitu Golesti Romanian mining sites for coals with inferior rank and those extracted from soil. The possibility of utilization of useless coal for energy-industry to introduce organic mass and humic acids in poor soils is sustained by these similarities. These coals introduced in soil could be ecological materials which give a better soil quality.

  20. 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.

  1. 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.

  2. Transformation of humic acid and halogenated byproduct formation in UV-chlorine processes.

    Science.gov (United States)

    Li, Tong; Jiang, Yan; An, Xiaoqiang; Liu, Huijuan; Hu, Chun; Qu, Jiuhui

    2016-10-01

    The synergistic effect of ultraviolet light (UV) and chlorine on the structural transformation of Humic Acid (HA) and formation of chloro-disinfection byproducts (DBPs) in water were investigated, with chlorination as a reference. The transformation and mineralization of HA were enhanced upon co-exposure to UV and chlorine. Electron spin resonance (ESR) studies revealed that hydroxyl radical (OH) and chlorine radical (Cl) were predominant active species in a pH range from 4 to 7, while Cl dominated at pH 2 and pH higher than 7. The impact of different radicals on the transformation of HA was investigated by UV254, fluorescence and TOC measurements. OH were found to be responsible for the removal of chromophoric groups and mineralization of HA, while Cl mainly reacted with HA and intermediates from HA degradation. Due to the competitive and synergistic reaction of OH and Cl with HA, higher removal of HA and lower formation of chloro-DBPs appeared in UV-chlorine than chlorination, thus the combined UV-chlorine processes should be a promising method for water purification. Copyright © 2016. Published by Elsevier Ltd.

  3. 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.

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

    Science.gov (United States)

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

    2016-12-01

    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 and molecular size distribution of HA by size exclusion chromatography. Trametes versicolor and Phanerochaete chrysosporium showed the highest HA removal efficiency, reaching about 80%. Laccase and manganese peroxidase were measured as extracellular enzymes and their relation to the HA removal by WRF was investigated. Results indicated that nitrogen limitation could enhance the WRF extracellular enzyme activity, but did not necessarily increase the HA removal by WRF. The mechanism of bioremediation by WRF was shown to involve biosorption of HA by fungal biomass and degradation of HA to smaller molecules. Also, contradicting previous reports, it was shown that the decolorization of HA by WRF could not necessarily be interpreted as degradation of HA. Biosorption experiments revealed that HA removal by fungal biomass is dependent not only on the amount of biomass as the sorbent, but also on the fungal species. The involvement of cytochrome P450 (CYP) enzymes was confirmed by comparing the HA removal capability of fungi with and without the presence of a CYP inhibitor. The ability of purified laccase from WRF to solely degrade HA was proven and the importance of mediators was also demonstrated.

  5. Influence of Humic Acid Complexation with Metal Ions on Extracellular Electron Transfer Activity

    Science.gov (United States)

    Zhou, Shungui; Chen, Shanshan; Yuan, Yong; Lu, Qin

    2015-01-01

    Humic acids (HAs) can act as electron shuttles and mediate biogeochemical cycles, thereby influencing the transformation of nutrients and environmental pollutants. HAs commonly complex with metals in the environment, but few studies have focused on how these metals affect the roles of HAs in extracellular electron transfer (EET). In this study, HA-metal (HA-M) complexes (HA-Fe, HA-Cu, and HA-Al) were prepared and characterized. The electron shuttle capacities of HA-M complexes were experimentally evaluated through microbial Fe(III) reduction, biocurrent generation, and microbial azoreduction. The results show that the electron shuttle capacities of HAs were enhanced after complexation with Fe but were weakened when using Cu or Al. Density functional theory calculations were performed to explore the structural geometry of the HA-M complexes and revealed the best binding sites of the HAs to metals and the varied charge transfer rate constants (k). The EET activity of the HA-M complexes were in the order HA-Fe > HA-Cu > HA-Al. These findings have important implications for biogeochemical redox processes given the ubiquitous nature of both HAs and various metals in the environment. PMID:26593782

  6. Dual-Pore Carbon Shells for Efficient Removal of Humic Acid from Water.

    Science.gov (United States)

    Yu, Hongxia; Zhang, Qiao; Dahl, Michael; Joo, Ji Bong; Wang, Xin; Wang, Lianjun; Yin, Yadong

    2017-11-16

    A template-mediated process for the preparation of mesoporous carbon shells with high surface area, dual-pore structure, and excellent performance in the adsorption of humic acid is reported. Their synthesis involves templating phenolic resin against wrinkled silica nanospheres, subsequent carbonization under Ar atmosphere, and final release of dual-pore mesoporous carbon shells by etching the silica templates. An additional silica layer was used to protect the phenolic resin from aggregation during carbonization, and its subsequent removal gives the carbon shells a hydrophilic surface, which significantly improves their dispersity in aqueous media. When used as adsorbents for humic acid removal, the as-prepared dual-pore mesoporous carbon shells show superior adsorption performance to activated carbon. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. 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.

  8. Metal ion-humic acid nanoparticle interactions: role of both complexation and condensation mechanisms.

    Science.gov (United States)

    Town, Raewyn M; van Leeuwen, Herman P

    2016-07-21

    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 anomalously high Donnan potentials, as well as intrinsic affinity constants for electrostatically associating ions such as Ca(2+). In contrast, the recently introduced counterion condensation - Donnan model (CCD) provides a physicochemically realistic description of the electrostatic contribution to metal ion binding by humic acid nanoparticles. The extent of Ca(2+)-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(ii), Pb, (ii) and Cu(ii) by HA also involves inner-sphere complex formation leading to intraparticulate metal species distributions with major proportions of condensed and complexed ions.

  9. 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.

  10. Equilibrium and kinetic studies on the adsorption of humic acid by activated sludge and Bacillus subtilis

    OpenAIRE

    Woranart Jonglertjunya; Tidathip Lertchutimakul

    2012-01-01

    This research is concerned with the adsorption of humic acid by activated sludge obtained from an alcoholic beverageplant and Bacillus subtilis (ATCC 6633). The effects of experimental factors such as initial pH, agitation speed, and types ofadsorbent have been studied to compare adsorption capacity. The characterisation of activated sludge and Bacillus subtilisadsorption were examined by investigating the adsorption isotherm and kinetics. The results showed that the type of adsorbent had a ...

  11. Layer-by-layer self-assembly of multilayer films based on humic acid

    Energy Technology Data Exchange (ETDEWEB)

    Xu Zhengxia; Hu Chenyang; Guoxin Hu, E-mail: hugx@sjtu.edu.c

    2011-04-29

    Multilayer films consisting of negatively charged humic acid and positively charged polyelectrolyte have been fabricated on various substrates using the layer-by-layer self-assembly technique. The thickness (linearly increasing with the square root of NaCl concentration) and refractive index of the films determined by ellipsometry can be regulated by ionic strength through adjusting the coiling of the polyelectrolyte chains for assembly. The cone-shaped features on surface obtained by atomic force microscope are derived from the negatively charged colloidal humic acid binding with polyelectrolyte cation. The smooth features are corresponding to the dissociated humic acid with carboxylate ion (-COO{sup -}) electrostatically attracted on polyelectrolyte cation. These results are verified by Fourier transform infrared spectra. The linear dependence of the peak current on the square root of the scan rate revealed by the cyclic voltammetry indicates that the redox process at the electrode surface is diffusion-limited and the charge transport does not involve the film itself.

  12. Aminoclay-induced humic acid flocculation for efficient harvesting of oleaginous Chlorella sp.

    Science.gov (United States)

    Lee, Young-Chul; Oh, Seo Yeong; Lee, Hyun Uk; Kim, Bohwa; Lee, So Yeun; Choi, Moon-Hee; Lee, Go-Woon; Park, Ji-Yeon; Oh, You-Kwan; Ryu, Taegong; Han, Young-Kyu; Chung, Kang-Sup; Huh, Yun Suk

    2014-02-01

    Biofuels (biodiesel) production from oleaginous microalgae has been intensively studied for its practical applications within the microalgae-based biorefinement process. For scaled-up cultivation of microalgae in open ponds or, for further cost reduction, using wastewater, humic acids present in water-treatment systems can positively and significantly affect the harvesting of microalgae biomass. Flocculation, because of its simplicity and inexpensiveness, is considered to be an efficient approach to microalgae harvesting. Based on the reported cationic aminoclay usages for a broad spectrum of microalgae species in wide-pH regimes, aminoclay-induced humic acid flocculation at the 5g/L aminoclay loading showed fast floc formation, approximately 100% harvesting efficiency, which was comparable to the only-aminoclay treatment at 5g/L, indicating that the humic acid did not significantly inhibit the microalgae harvesting behavior. As for the microalgae flocculation mechanism, it is suggested that cationic nanoparticles decorated on macromolecular matters function as a type of network in capturing microalgae. Copyright © 2013 Elsevier Ltd. All rights reserved.

  13. Generation of humic and fulvic acid from Callovo-Oxfordian clay under high alkaline conditions

    Energy Technology Data Exchange (ETDEWEB)

    Claret, Francis; Schafer, Thorsten; Bauer, Andreas; Buckau, Gunnar [Forschungszentrum Karlsruhe, Institut fur Nukleare Entsorgungstechnik, Karlsruhe D-76021 (Germany)

    2003-12-30

    Low-carbon-containing clay from four different depths (447 to 516 m) of the Meuse Haute Marne (MHM) site is kept in contact with alkaline solution simulating conditions expected from cement dissolution in the near-field of a nuclear waste repository. Original organic material in the clay consists mainly of aliphatic hydrophobic compounds basically without oxygen-containing functional groups. After contact with 'solid young fluid' (mimicking cement dissolution, initial pH 13.22) for approximately one and a half years, high concentrations of hydrophilic organic matter are found (243-355 mg DOC/L). Characterization by solubility behavior, UV/Vis absorption, IR and fluorescence properties show that the dissolved hydrophilic organic matter has the characteristic features of humic and fulvic acids. Estimation of humic and fulvic acid content via UV/Vis spectroscopy results in 97.5 ({+-}9.7)% of DOC being humic and fulvic acid. The results indicate that this could be an important source of complexing mobile organic matter influencing the mobility of radionuclides in a nuclear waste repository under consideration for this site. Investigations were conducted under oxic conditions representing the situation in the excavation disturbed zone (EDZ) of an underground facility. Sample amounts were very small and thus some characterization results are partly of preliminary character.

  14. A Fluorescence Quenching Analysis of the Binding of Fluoroquinolones to Humic Acid.

    Science.gov (United States)

    Ferrie, Ryan P; Hewitt, Gregory E; Anderson, Bruce D

    2017-11-01

    Fluorescence quenching was used to investigate the interaction of six fluoroquinolones with humic acid. Static quenching was observed for the binding of ciprofloxacin, enoxacin, fleroxacin, levofloxacin, norfloxacin, and ofloxacin to humic acid. The equilibrium binding constants were found from Stern-Volmer plots of the data. The quenching experiments were repeated over a temperature range of 25-45 ℃ and van't Hoff plots were generated. From these linear plots, thermodynamic values were calculated for Δ H, Δ G, and Δ S for each of the fluoroquinolones. The equilibrium binding constants were found to be <1 for all the antibiotics studied. The calculated ΔH values were all negative and ranged from -9.5 to -27.6 kJ/mol. The high water solubility of the antibiotics and low ΔH of binding suggests that the antibiotics will be transported easily through the environment. Finally, whether the fluoroquinolones are in a protonated, deprotonated, or partially protonated state is found to correlate to the strength of binding to humic acid.

  15. Effect of reduced humic acid on the transport of ferrihydrite nanoparticles under anoxic conditions.

    Science.gov (United States)

    Liao, Peng; Li, Wenlu; Wang, Dengjun; Jiang, Yi; Pan, Chao; Fortner, John D; Yuan, Songhu

    2017-02-01

    Humic acid (HA) occurs ubiquitously in the subsurface environments and is well-known to play a critical role in the fate and transport of ferrihydrite nanoparticles (NPs) and NPs-associated contaminants. Under anoxic conditions, HA can readily be reduced by microorganisms or geochemical reducing species, and the mechanisms and kinetics of ferrihydrite reduction by reduced HA (HAred) are well-documented; however, the role of these redox reactions on the transport of ferrihydrite NPs is largely underestimated. This study provides new knowledge regarding the role of HA (both reduced HA (HAred) and oxidized HA (HAox)) of environmentally relevant concentrations (0-50 mg C/L) on the transport of ferrihydrite NPs in anoxic sand columns. Our findings show that, regardless of the redox state, the presence of a low concentration of HA (3 mg C/L) inhibited ferrihydrite NP's transport due to enhanced aggregation (and deposition) between positively charged ferrihydrite NPs and negatively charged HA molecules. In contrast, higher HA (both HAred and HAox) concentration (≥10 mg C/L) significantly enhanced the mobility of ferrihydrite NPs, primarily due to the enhanced electrostatic and steric stabilization originating from excessively adsorbed HA molecules. Interestingly, the transport of ferrihydrite NPs is substantially lower in the presence of HAred than in the presence of HAox. This distinct effect (HAred vs. HAox) on the particle transport is attributed to the fact that reductive dissolution of ferrihydrite NPs occurs in the presence of HAred (ferrihydrite dissolves and thus total breakthrough decreases), but not in the presence of HAox. Furthermore, the abatement extent of ferrihydrite NPs transport triggered by the presence of HAred is dependent on dissolved HAred concentration. Taken together, our findings provide direct, and much needed insights into the distinct roles of redox state of HA on the transport of redox-sensitive metal-bearing NPs in porous media

  16. 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.

  17. 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.

  18. Insights into the Role of Humic Acid on Pd-catalytic Electro-Fenton Transformation of Toluene in Groundwater

    Science.gov (United States)

    Liao, Peng; Al-Ani, Yasir; Malik Ismael, Zainab; Wu, Xiaohui

    2015-01-01

    A recently developed Pd-based electro-Fenton (E-Fenton) process enables efficient in situ remediation of organic contaminants in groundwater. In the process, H2O2, Fe(II), and acidic conditions (~pH 3) are produced in situ to facilitate the decontamination, but the role of ubiquitous natural organic matters (NOM) remain unclear. This study investigated the effect of Aldrich humic acid (HA) on the transformation of toluene by the Pd-based E-Fenton process. At pH 3 with 50 mA current, the presence of HA promoted the efficiency of toluene transformation, with pseudo-first-order rate constants increase from 0.01 to 0.016 as the HA concentration increases from 0 to 20 mg/L. The HA-enhanced toluene transformation was attributed to the accelerated thermal reduction of Fe(III) to Fe(II), which led to production of more hydroxyl radicals. The correlation of the rate constants of toluene transformation and HA decomposition validated hydroxyl radical (·OH) as the predominant reactive species for HA decomposition. The finding of this study highlighted that application of the novel Pd-based E-Fenton process in groundwater remediation may not be concerned by the fouling from humic substances. PMID:25783864

  19. 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

  20. Removal of Trace Levels of Cu(II) from Seawater by Co-precipitation with Humic Acids.

    Science.gov (United States)

    Iwai, Hisanori

    2017-01-01

    To maintain performance related to fuel consumption and maneuverability, the bottom of ships are painted with antifouling paint that contains Cu2O as a biocidal pigment. However, in enclosed coastal areas around dockyards, some of the Cu(II) contained in the paint is eluted into the surrounding water. The present study examined the removal of Cu from seawater by co-precipitation with humic acids (HAs). After precipitating the HA in seawater, the amount of Cu(II) in the supernatant was colorimetrically measured by a colorimetry using bathocuproine. The removal efficiency (RE%) for micromolar Cu(II) increased with increasing initial concentrations of HAs. An RE of 90% was obtained using an HA derived from hardwood bark compost. Aromatic components in the HA that contained highly substituted acidic functional groups appeared to enhance the removal of Cu(II). The findings reported herein indicate that HAs represent a useful material for removing trace levels of Cu from seawater.

  1. Evaluation of Humic Acid and Tannic Acid Fouling in Graphene Oxide-Coated Ultrafiltration Membranes.

    Science.gov (United States)

    Chu, Kyoung Hoon; Huang, Yi; Yu, Miao; Her, Namguk; Flora, Joseph R V; Park, Chang Min; Kim, Suhan; Cho, Jaeweon; Yoon, Yeomin

    2016-08-31

    Three commercially available ultrafiltration (UF) membranes (poly(ether sulfone), PES) that have nominal molecular weight cut-offs (5, 10, and 30 kDa) were coated with graphene oxide (GO) nanosheets. Field-emission scanning electron microscopy, Fourier-transform infrared spectroscopy, confocal laser scanning microscopy, water contact angle measurements, and X-ray photoelectron spectroscopy were employed to determine the changed physicochemical properties of the membranes after GO coating. The water permeability and single-solute rejection of GO-coated (GOC) membranes for humic acid (HA) molecules were significantly higher by approximately 15% and 55%, respectively, compared to those of pristine UF membranes. However, the GOc membranes for single-solute tannic acid (TA) rejection showed similar trends of higher flux decline versus pristine PES membranes, because the relatively smaller TA molecules were readily adsorbed onto the membrane pores. When the mixed-solute of HA and TA rejection tests were performed, in particular, the adsorbed small TA molecules resulted in irreversible membrane fouling due to cake formation and membrane pore blocking on the membrane surface for the HA molecules. Although both membranes showed significantly higher flux declines for small molecules rejection, the GOc membranes showed better performance than the pristine UF membranes in terms of the rejection of various mixed-solute molecules, due to higher membrane recovery and antifouling capabilities.

  2. 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.

  3. Influence of soil humic acid and fulvic acid on sorption of thorium(IV) on MX-80 bentonite

    Energy Technology Data Exchange (ETDEWEB)

    Xu, D.; Wang, X.K.; Chen, C.L.; Zhou, X.; Tan, X.L. [Inst. of Plasma Physics, Chinese Academy of Sciences, Hefei (China)

    2006-07-01

    Th(IV) is considered herein as a chemical analogue of other actinides (IV). Effect of pH, ionic strength and humic acid/fulvic acid concentrations on the sorption of thorium(IV) to MX-80 bentonite was studied by batch technique. The sorption isotherms were acquired by varying pH in the range of 0.5-12 and FA/HA concentration in the range of 2-20 mg/L. The results indicate that soil fulvic acid has higher carboxylic content than humic acid, and has stronger positive influence on the sorption of Th(IV) on bentonite at low pH values than humic acid. The increase of FA/HA concentration results in a slight increase of Th(IV) sorption on FA/HA coated bentonite. The results of no drastic effect of different addition sequences of FA/HA and Th(IV) to bentonite suspension on Th(IV) sorption in the ternary system HA/FA-Th(IV)-bentonite indicate that both the Th(IV)-HA/FA complexation and HA/FA-bentonite sorption do not affect the sorption of Th(IV) on HA/FA coated bentonite obviously. The samples were also measured by SEM method and the results show that the surface properties of different samples are different. (orig.)

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

    Science.gov (United States)

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

    2008-06-01

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Aquino, Adelia J.A. [Institute for Theoretical Chemistry, University of Vienna, Waehringer Strasse 17, A-1090 Vienna (Austria); Institute of Soil Research, University of Natural Resources and Applied Life Sciences Vienna, Peter-Jordan-Strasse 82, A1190 Vienna (Austria)], E-mail: adelia.aquino@univie.ac.at; Tunega, Daniel [Institute for Theoretical Chemistry, University of Vienna, Waehringer Strasse 17, A-1090 Vienna (Austria); Institute of Soil Research, University of Natural Resources and Applied Life Sciences Vienna, Peter-Jordan-Strasse 82, A1190 Vienna (Austria); Pasalic, Hasan [Institute for Theoretical Chemistry, University of Vienna, Waehringer Strasse 17, A-1090 Vienna (Austria); Haberhauer, Georg [ARC Seibersdorf Research, A-2444 Seibersdorf (Austria); Gerzabek, Martin H. [Institute of Soil Research, University of Natural Resources and Applied Life Sciences Vienna, Peter-Jordan-Strasse 82, A1190 Vienna (Austria); Lischka, Hans [Institute for Theoretical Chemistry, University of Vienna, Waehringer Strasse 17, A-1090 Vienna (Austria)

    2008-06-16

    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.

  6. Influence of humic acid on the transport behavior of bacteria in quartz sand.

    Science.gov (United States)

    Yang, Haiyan; Kim, Hyunjung; Tong, Meiping

    2012-03-01

    The significance of natural organic matter (NOM) on the transport of bacteria in packed porous media (quartz sand) was examined in both NaCl and CaCl(2)-NaCl mixing solutions at pH 6.0. Three representative cell types (with EPS), Rhodococcus sp. QL2 (Gram-positive, non-motile), Escherichia coli BL21 (Gram-negative, non-motile), and E. coli C3000 (Gram-negative, motile), were utilized to systematically determine the influence of NOM (Suwannee River humic acid (SRHA)) on cell transport behavior. To investigate the significance of SRHA on transport of bacteria without EPS on cell surfaces, experiments for treated cells with the removal of EPS from cell surfaces were also performed. The breakthrough plateaus for all examined bacteria with the presence of SRHA (1 mg L(-1)) in solutions were higher than those with the absence of SRHA under all examined conditions, indicating that the presence of SRHA in solutions enhanced cell transport regardless of cell types (Gram-negative or Gram-positive), motility (non-motile or motile), presence or absence of EPS on cell surfaces, and solution chemistry (ionic strength and ion valence). Zeta potentials for bacteria and quartz sand with the presence of SRHA were similar as those without SRHA present in solutions, suggesting that SRHA did not alter the surface charge of bacteria or sand, thus the enhanced cell transport by SRHA was not likely driven by alteration in the surface charge of either cell or quartz sand. SRHA pre-equilibration experiments demonstrated that the site competition by a portion of SRHA and the repelling deposition by suspended SRHA contributed to the decreased cell deposition observed with the presence of SRHA in bacteria suspension. Copyright © 2011 Elsevier B.V. All rights reserved.

  7. 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.

  8. Effect of humic acid, fulvic acid, pH and temperature on the sorption-desorption of Th(IV) on attapulgite

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Q.H. [Lanzhou Univ., Gansu (China). Radiochemistry Lab.; Chinese Academy of Sciences, Hefei (China). Inst. of Plasma Physics; Wu, W.S.; Xu, J.Z.; Niu, Z.W. [Lanzhou Univ., Gansu (China). Radiochemistry Lab.; Song, X.P. [Anhui Medical College, Hefei (China); Hu, J. [Chinese Academy of Sciences, Hefei (China). Inst. of Plasma Physics

    2008-07-01

    Sorption of Th(IV) on attapulgite as a function of pH and temperature in the presence and absence of humic acid and fulvic acid was studied under ambient conditions using batch technique. The results indicated that sorption of Th(IV) on attapulgite was strongly affected by pH values. The presence of humic acid and fulvic acid enhanced the sorption of Th(IV) at low pH values and no significant influence was observed at high pH values. Sorption of Th(IV) was mainly dominated by surface complexation. Sorption of Th(IV) increased with increasing temperature of the system. Enthalpy ({delta}H{sup 0}), entropy ({delta}S{sup 0}) and Gibbs free energy ({delta}G{sup 0}) were calculated from the temperature dependent sorption data, and the results indicated that the sorption of Th(IV) on attapulgite was a spontaneous process. The results of sorption and desorption of Th(IV) on HS bound attapulgite indicated that the sorption of Th(IV) on HS-attapulgite hybrids was reversible. (orig.).

  9. Understanding Humic Acid / Zr(IV) Interaction — A Spectromicroscopy Approach

    Science.gov (United States)

    Rothe, Jörg; Plaschke, Markus; Denecke, Melissa A.

    2007-02-01

    Complexation of Zr(IV) by humic acid (HA) and polyacrylic acid (PAA) is investigated from the point of view of the organic ligand. STXM Spectromicroscopy and C 1s-NEXAFS point to different interaction mechanisms between Zr(IV) cations and oxo/hydroxo colloids and PAA. Under conditions where the metal aquo ion is stable, strong complexes are formed. In contrast, unspecific surface coating is identified when PAA is contacted with Zr(IV) oxo/hydroxide colloids. HA exhibits similar C 1s-NEXAFS features indicating a complexation reaction.

  10. Influence of herbicide structure, clay acidity, and humic acid coating on acetanilide herbicide adsorption on homoionic clays.

    Science.gov (United States)

    Liu, Weiping; Gan, Jianying; Yates, Scott R

    2002-07-03

    Adsorption of chloroacetanilide herbicides on homoionic montmorillonite was studied by coupling batch equilibration and FT-IR analysis. Adsorption decreased in the order metolachlor > acetochlor > alachlor > propachlor on Ca(2+)- or Mg(2+)-saturated clays and in the order metolachlor > alachlor > acetachlor > propachlor on Al(3+)- or Fe(3+)-saturated clays. FT-IR spectra showed that the carbonyl group of the herbicide molecule was involved in bonding. For the same herbicide, adsorption of alachlor, acetachlor, and metolachlor on clay followed the order Ca(2+) approximately Mg(2+) < Al(3+) < or = Fe(3+), which coincided with the increasing acidity of homoionic clays. Adsorption of propachlor, however, showed an opposite dependence, suggesting a different governing interaction. In clay and humic acid mixtures, herbicide adsorption was less than that expected from independent additive adsorption by the individual constituents, and the deviation was dependent on the clay-to-humic acid ratio, with the greatest deviation consistently occurring at a 60:40 clay-to-humic acid ratio.

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

    Science.gov (United States)

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

    2015-12-01

    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., PO 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. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. 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.

  13. 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

  14. Humic substances in a soil treated with household compost under ...

    African Journals Online (AJOL)

    Tillage (hoeing) significantly enhanced the formation of humic substances (HS) in the soil. Formation of humic substance (HS) was not favoured by fertilizer application which gave lower % HS than the control. Fulvic acid fraction was higher in compost amended soil. Nigerian Journal of Soil Science Vol. 15 2005: 86-89 ...

  15. Effects of cluster reduction, herbagreen and humic acid applications ...

    African Journals Online (AJOL)

    Jane

    2011-06-22

    Jun 22, 2011 ... formation of CO2 within the cell. It enhances the efficiency of plant photosynthesis and enzyme activity, and increa- ses the immune system, improves plant health and productivity ... while the lowest yield was obtained by control application with 14.7 kg (Akyüz, 2000). In round seedless grape cultivar, the ...

  16. 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

  17. Title: Effects of supplementing humic/fulvic acid on rumen ...

    African Journals Online (AJOL)

    Casey McMurphy

    on serum urea nitrogen, rumen pH, rumen ammonia nitrogen and volatile fatty acid (VFA) production. Steers .... cheesecloth (BBA Nonwovens, Simpsonville, SC, USA) until 100 mL of rumen fluid was obtained in a 150 ... 500 °C), dry matter (DM; oven dried at 110 °C), crude protein (CP; g/kg N x 6.25; LECO Corporation, St.

  18. Influence of humic acid on the Am(III) sorption onto kaolinite

    Energy Technology Data Exchange (ETDEWEB)

    Krepelova, A.; Sachs, S.; Bernhard, G. [Forschungszentrum Rossendorf e.V. (FZR), Dresden (Germany). Inst. fuer Radiochemie

    2011-07-01

    The sorption of americium(III), (Am(III)), onto kaolinite was studied in batch experiments in the absence and presence of humic acid (HA) ([Am(III)]{sub 0} = 1 x 10{sup -6} M, [HA]{sub 0} = 0 or 10 mg/L, I = 0.01 M NaClO{sub 4}, pH = 3-10, p{sub CO{sub 2}} = 10{sup -3.5} atm, solid-to-liquid ratio (S/L)=1 or 4 g/L). The results show that the Am(III) sorption onto kaolinite is influenced by S/L, the presence of HA and the pH value. In the absence of HA, Am(III) exhibits a very strong and almost pH independent sorption onto kaolinite at the S/L ratio of 4 g/L. In the presence of HA, there are small differences in the Am(III) sorption compared to the HA free system. At pH values < 5, HA very slightly enhances the sorption of Am(III). Conversely, at pH values {>=} 5.5, the presence of HA decreases the sorption of Am(III) due to the formation of dissolved Am(III) humate complexes. The decrease of S/L from 4 to 1 g/L has a significant effect on the Am(III) sorption onto kaolinite. A sorption edge occurs at pH 6 and the influence of carbonate on the Am(III) sorption at higher pH values becomes evident. Furthermore, the influence of HA on the Am(III) sorption onto kaolinite is more pronounced. The Am(III) sorption results are compared to literature data and to those of U(VI) sorption onto kaolinite obtained under the same experimental conditions. (orig.)

  19. Pyrene fate affected by humic acid amendment in soil slurry systems

    Science.gov (United States)

    Liang, Yanna; Sorensen, Darwin L; McLean, Joan E; Sims, Ronald C

    2008-01-01

    Background Humic acid (HA) has been found to affect the solubility, mineralization, and bound residue formation of polycyclic aromatic hydrocarbons (PAHs). However, most of the studies on the interaction between HA and PAH concentrated on one or two of the three phases. Few studies have provided a simple protocol to demonstrate the overall effects of HA on PAH distribution in soil systems for all three phases. Methods In this study, three doses of standard Elliott soil HA (ESHA), 15, 187.5, and 1,875 μg ESHA/g soil slurry, were amended to soil slurry systems. 14C-pyrene was added to the systems along with non-radiolabeled pyrene; 14C and 14CO2 were monitored for each system for a period of 120 days. Results The highest amendment dose significantly increased the 14C fraction in the aqueous phase within 24 h, but not after that time. Pyrene mineralization was significantly inhibited by the highest dose over the 120-day study. While organic solvent extractable 14C decreased with time in all systems, non-extractable or bound 14C was significantly enhanced with the highest dose of ESHA addition. Conclusion Amendment of the highest dose of ESHA to pyrene contaminated soil was observed to have two major functions. The first was to mitigate CO2 production significantly by reducing 14CO2 from 14C pyrene mineralization. The second was to significantly increase stable bound 14C formation, which may serve as a remediation end point. Overall, this study demonstrated a practical approach for decontamination of PAH contaminated soil. This approach may be applicable to other organic contaminated environments where active bioremediation is taking place. PMID:18783628

  20. 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.

  1. Reduction of toxic Cr(VI)-humic acid in an ionic liquid

    Science.gov (United States)

    Huang, Hsin-Liang; Huang, Hsin-Hung; Wei, Yu Jhe

    2017-07-01

    Remediation of soil contaminated by toxic hexavalent chromium species associated with humic acid (Cr(VI)-HA) and absorbed Cr(VI) in pores frequently experiences technical difficulties. In the present work, a feasibility study for extraction of the Cr(VI) species from a molecular sieve MCM-41 (Mobil Composition of Matter No. 41) that was used to simulate the pore system of soil, with a green solvent (ionic liquid), 1-butyl-3-methylimidazolium chloride ([C4mim][Cl]), was carried out. After a 30-min extraction, approximately 70% of the Cr(VI) species can be extracted. By component fitted X-ray absorption near edge structure (XANES) spectroscopy, about 48% of the Cr(VI)-HA are reduced to form less toxic species (Cr(III)-HA) during extraction with [C4mim][Cl]. Note that the Cr-O in the [C4mim][Cl] phase has a slightly greater bond distance (BD) (0.162 nm) possibly due to the fact of that the fraction of Cr(III) is increased in the extraction process. The non-extractable chromium remaining in MCM-41 has a much greater fraction of Cr(III) (78%) and its BD is further increased to 0.195 nm. The coordination numbers of chromium for the 1st shell Cr-O in the Cr(VI) and Cr(III) species are in the range of 2.4-2.9, suggesting that chromium is chelated with HA and adsorbed in MCM-41. The 1H NMR data also suggest that the enhanced reduction of the Cr(VI) species may be related to interactions between chromium species and electron-rich imidazole ring of the [C4mim]+. This work also exemplifies that the fate of toxic chromium species in the complicated remediation of contaminated soils can be revealed in a molecule-scale study by synchrotron X-ray absorption spectroscopy.

  2. [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

  3. 15N NMR investigation of the covalent binding of reduced TNT amines to soil humic acid, model compounds, and lignocellulose

    Science.gov (United States)

    Thorn, K.A.; Kennedy, K.R.

    2002-01-01

    The five major reductive degradation products of TNT-4ADNT (4-amino-2,6-dinitrotoluene), 2ADNT (2-amino-4,6-dinitrotoluene), 2,4DANT (2,4-diamino-6-nitrotoluene), 2,6DANT (2,6-diamino-4-nitrotoluene), and TAT (2,4,6-triaminotoluene)-labeled with 15N in the amine positions, were reacted with the IHSS soil humic acid and analyzed by 15N NMR spectrometry. In the absence of catalysts, all five amines underwent nucleophilic addition reactions with quinone and other carbonyl groups in the soil humic acid to form both heterocyclic and nonheterocyclic condensation products. Imine formation via 1,2-addition of the amines to quinone groups in the soil humic acid was significant with the diamines and TAT but not the monoamines. Horseradish peroxidase (HRP) catalyzed an increase in the incorporation of all five amines into the humic acid. In the case of the diamines and TAT, HRP also shifted the binding away from heterocyclic condensation product toward imine formation. A comparison of quantitative liquid phase with solid-state CP/MAS 15N NMR indicated that the CP experiment underestimated imine and heterocyclic nitrogens in humic acid, even with contact times optimal for observation of these nitrogens. Covalent binding of the mono- and diamines to 4-methylcatechol, the HRP catalyzed condensation of 4ADNT and 2,4DANT to coniferyl alcohol, and the binding of 2,4DANT to lignocellulose with and without birnessite were also examined.

  4. 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.

  5. The effect of the humic acid and garlic (Allium sativum L. on performance parameters and carcass characteristic of broiler chicken

    Directory of Open Access Journals (Sweden)

    Veronika PISTOVÁ

    2016-12-01

    Full Text Available In this study the effect of humic acids and humic acids and garlic powder (Allium sativum L. combination on performance parameters and carcass characteristic of broiler chickens were studied. A total of 120 Ross 308 broiler chickens were divided into 3 treatments (n=40. The control group of chickens was fed complete feed mixtures without any additives. Treatment T1 was fed complete feed mixtures containing 1% of humic acid. Treatment T2 was fed complete feed mixtures containing 1.8% of humic acid and 0.2% of garlic powder (Allium sativum L.. At the end of the experiment was average body weight (values in the order of the groups: 1796.4±188.1; 1999.1±355.8 and 1958.6±201.2 g±SD significantly higher (P≤0.05 in both treatments groups compared to control group. In T1 was weight of gizzard (values in the order of the groups: 34.9±5.2; 43.1±9.4 and 38.9±7.0 g±SD significantly higher (P≤0.05 compared to control group. Carcass weight, weight of heart weight of liver and carcass yield of treatments groups was higher, but differences in these indicators were not statistically significant (P≥0.05. The results of this experiment indicate that humic acids may by an alternative replacement of feed antibiotics.

  6. 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 F1 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.

  7. 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

  8. 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.

  9. 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.

  10. 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

  11. 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.

  12. Adsorption of humic acid from landfill leachate by nitrogen-containing activated carbon

    Science.gov (United States)

    Qin, Hangdao; Meng, Jianling; Chen, Jing

    2017-01-01

    Humic substances are the major contaminants in the landfill leachate, while activated carbon adsorption is an effective treatment method. AC was modified with nitric acid, ammonium hydroxide and urea, which introduced functional groups onto AC surface. The adsorption capacity of HA on AC were investigated. ACN showed the highest HA adsorption capacity, increasing more than 20% compared to the parent one. The results indicated that the mesoporous structure favored HA adsorption and the nitrogen-containing basic groups played an important role in the adsorption of HA.

  13. 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...

  14. Effect of humic acids on electricity generation integrated with xylose degradation in microbial fuel cells

    DEFF Research Database (Denmark)

    Huang, Liping; Angelidaki, Irini

    2008-01-01

    Pentose and humic acids (HA) are the main components of hydrolysates, the liquid fraction produced during thermohydrolysis of lignocellulosic material. Electricity generation integrated with xylose (typical pentose) degradation as well as the effect of HA on electricity production in microbial fuel...... degradation and formation of more oxidized products (acetate and formate) as well as less reduced products (lactate and ethanol) compared to the controls. The reduced power generation in the presence of DMW was attributed to the presence of bacterial inhibitors such as phenolic compounds. Therefore, new...

  15. 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.

  16. Fractionation of Suwannee River Fulvic Acid and Aldrich Humic Acid on α-Al2O3: Spectroscopic Evidence

    Energy Technology Data Exchange (ETDEWEB)

    Claret, F.; Schäfer, T; Brevet, J; Reiller, P

    2008-01-01

    Sorptive fractionation of Suwannee River Fulvic Acid (SRFA) and Purified Aldrich Humic Acid (PAHA) on a-Al2O3 at pH 6 was probed in the supernatant using different spectroscopic techniques. Comparison of dissolved organic carbon (DOC) analysis with UV/vis spectrophotometric measurements at 254 nm, including specific UV absorbance (SUVA) calculation, revealed a decrease in chromophoric compounds for the nonsorbed extracts after a 24 h contact time. This fractionation, only observable below a certain ratio between initial number of sites of humic substances and of a-Al2O3, seems to indicate a higher fractionation for PAHA. C(1s) near-edge X-ray absorption fine structure spectroscopy (NEXAFS) confirmed this trend and points to a decrease in phenolic moieties in the supernatant and to an eventual increase in phenolic moieties on the surface. Time-resolved luminescence spectroscopy (TRLS) of Eu(III) as luminescent probe showed a decrease in the ratio between the 5D0?7F2 and 5D0?7F1 transitions for the fractionated organic matter (OM) that is thought to be associated with a lower energy transfer from the OM to Eu(III) due to the loss of polar aromatics. These modifications in the supernatant are a hint for the modification of sorbed humic extracts on the surface.

  17. Quantum chemical modeling of humic acid/air equilibrium partitioning of organic vapors.

    Science.gov (United States)

    Niederer, Christian; Goss, Kai-Uwe

    2007-05-15

    Classical approaches for predicting soil organic matter partition coefficients of organic compounds require a calibration with experimental partition data and, for good accuracy, experimental compound descriptors. In this study we evaluate the quantum chemical model COSMO-RS in its COSMOtherm implementation for the prediction of about 200 experimental Leonardite humic acid/air partition coefficients without calibration or experimental compound descriptors, but simply based on molecular structures. For this purpose a Leonardite Humic Acid model monomer limited to 31 carbon atoms was derived from 13C NMR analysis, elemental analysis, and acidic function analysis provided in the literature. Altogether the COSMOtherm calculations showed a good performance and we conclude that it may become a very promising tool for the prediction of sorption in soil organic matter for compounds for which the molecular structure is the only reliable information available. COSMOtherm can be expected to be very robust with respectto new and complex compound structures because its calculations are based on a fundamental assessment of the underlying intermolecular forces. In contrast, other empirical models that are also based on the molecular structure of the sorbate have an application domain that is limited by their calibration data set that is often unknown to the user.

  18. Adsorption of MCPA on goethite and humic acid-coated goethite.

    Science.gov (United States)

    Iglesias, A; López, R; Gondar, D; Antelo, J; Fiol, S; Arce, F

    2010-03-01

    Anionic pesticides are adsorbed on the mineral oxide fraction of the soil surface but considerably less on the organic fraction, so that the presence of organic matter causes a decrease in the amount of pesticide adsorbed, and may affect the mechanism of adsorption. In the present study we investigated the adsorption of the weak acid pesticide MCPA on the surface of goethite and of humic acid-coated goethite, selected as models of the mineral oxide fraction and organic components present in soil systems. Adsorption of the anionic form of the pesticide on goethite fitted an S-type isotherm and the amount adsorbed increased as the ionic strength decreased and the pH of the medium decreased. Application of the charge distribution multi site complexation model (CD-MUSIC model) enabled interpretation of the results, which suggested the formation of inner and outer sphere complexes between the pesticide and the singly-coordinated surface sites of goethite. Less pesticide was adsorbed on the humic acid-coated goethite than on the bare goethite and the pattern fitted an L-type isotherm, which indicates a change in the mechanism of adsorption. Simplified calculations with the CD-MUSIC model enabled interpretation of the results, which suggested that the pesticide molecules form the same type of surface complexes as in the previous case. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

  19. Humus and Humic Acids of Luvisol and Cambisol of Jiguli Ridges, Samara Region, Russia

    Directory of Open Access Journals (Sweden)

    Evgeny Abakumov

    2009-01-01

    Full Text Available Luvisols and Cambisols are two types of sub-boreal soils, which are known as continental and humid-ocean types of soils in deciduous forests respectively. Morphological features of soil, which are frequently used as the main argument in solum diagnostics, are subjective and do not give final decision that continental Cambisols are a specific type of soils different from Luvisols. These soils were studied in a mountain massive—Jiguli ridges of Samara region, Russia, East European part. Humid climate of northern slopes leads to formation of brown type of humic acids (HA, while the conditions of eastern slopes assist to formation of gray HA. These HAs of different soils are different in elemental composition (C and N are higher in Cambisols, O is higher in Luvisols, carbon species according to 13-C NMR (aromaticity is higher in Luvisols, while the aliphatic, carbonylic and carboxylic compounds are higher in Cambisols. Cambisols are characterized by dominance of fulvic acids (FAs on HAs, while the ratio of HA to FA groups in Luvisols is about 1,0. Essential differences in humus composition and humic acids properties confirm that local humid climate in continental forest-steppe leads to formation of Cambisols instead of zonal Luvisols.

  20. Large temperature-induced red shift of G-band of functionalized graphene nanosheets synthesized from humic acid

    Science.gov (United States)

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

    2016-10-01

    For the first time, temperature dependence of the G-band frequency for the functionalized graphene nanosheets synthesized using humic acid as precursor has been investigated. The Raman measurements has been performed using the excitation wavelength 514.5 nm and in the temperature range 23-116 °C. The prepared samples showed a negative temperature coefficient as large as -0.087 ± 0.008 cm-1/°C. Relatively large red shift of the G-band has been observed as the substrate temperature increases which indicates the higher sensitivity of the G-band peak position when the temperature varies. Such behavior has been attributed to the large contribution of the thermal expansion due to the lower Young's modulus of the reduced humic acid. This finding is important and opens the door for new applications of reduced humic acid as low cost, environmentally friendly and scalable material.

  1. Effect of ionic strength on complexation of Pu(IV) with humic acid

    Energy Technology Data Exchange (ETDEWEB)

    Szabo, G.; Guezi, J. [National Research Inst. for Radiobiology and Radiohygiene, Budapest (Hungary); Reiller, P. [Commissariat a l' Energie Atomique, CE Saclay, Nuclear Energy Div./DPC/SECR, Lab. de Speciation des Radionucleides et des Molecules, Gif-sur-Yvette (France); Miyajima, T. [Dept. of Chemistry, Saga Univ. (Japan); Bulman, R.A. [Radiation Protection Div., Health Protection Agency, Chilton, Didcot (United Kingdom)

    2010-07-01

    Successful geochemical modelling of the migration of radioactive materials, such as the transuranic elements, from nuclear waste repositories is dependent upon an understanding of their interaction with biogeopolymers such as humic acids, the most likely complexing agents in groundwaters. An established silica/humic acid composite has been evaluated as a model substrate for naturally occurring humate-coated minerals that are likely to be present in the vicinity of the repositories. The binding of Pu(IV), the highly likely oxidation station, by the silica/humic substrate was examined at pH 4 in the range 0.02 to 3.00 M NaClO{sub 4} by the titration method. Pu(IV)-humate conditional stability constants have been evaluated from data obtained from these experiments by using non-linear regression of binding isotherms. The results have been interpreted in terms of complexes of 1: 1 stoichiometry. Analysis of the complex formation dependency with ionic strength shows that the effect of ionic strength on humate complexation of Pu(IV) is not dramatically pronounced. The complexation constants are evaluated for the humate interaction with Pu{sup 4-} and Pu(OH){sub 3}{sup +}, at pH 4. The complexation constants are found, respectively, to be log{sup HA}{beta}{sup 0}(Pu{sup 4+}) = 16.6 {+-} 0.3 and log{beta}{sup 0}{sub 1.3.1} = 46.6 {+-} 2.3. The estimations through analogy from previous results a are in agreement with these new experimental data (orig.)

  2. Simultaneous analysis of free and humic acid complexed europium and gadolinium species by CE-ICP-MS

    Energy Technology Data Exchange (ETDEWEB)

    Kautenburger, R.; Nowotka, K.; Beck, H.P. [Institut fuer Anorganische und Analytische Chemie und Radiochemie, Universitaet des Saarlandes, P.O. Box 151150, 66041 Saarbruecken (Germany)

    2005-07-01

    Full text of publication follows: For the long-term safety assessment of waste repositories, detailed information about geo-chemical behaviour of radioactive and toxic metal ions under environmental conditions (geological matrix and aquifer systems) is necessary. It includes knowledge about the mechanism of relevant geochemical reactions, as well as thermodynamic and kinetic data. Several previous studies have shown that humic acid can play an important role in the immobilisation or mobilization of metal ions due to complexation and colloid formation. In this project we investigate the complexation behaviour of humic acid (purified Aldrich humic acid) and its influence on the migration of the lanthanides europium and gadolinium (homologues of the actinides americium and curium) in the the ternary system consisting of these heavy metals, humic acid and kaolinite (KGa-1b) as geological model system under conditions close to nature. Capillary electrophoresis (CE, Beckman Coulter P/ACE MDQ), with its excellent separation performance, was coupled to Inductively Coupled Plasma Mass Spectrometry (ICP-MS, VG Elemental Plasma Quad 3) to obtain a high sensitivity for the determination of the rare earth elements europium (Eu{sup 3+}) and gadolinium (Gd{sup 3+}) and their complexes with humic acid. Additionally, the used humic acid was halogenated with iodine as ICP-MS marker. A fused-silica capillary was flexibly fitted into a MicroMist 50 {mu}l nebulizer with a Cinnabar cyclonic spray chamber. The chamber was chilled to a temperature of 4 deg. C for best sensitivity. 200 ppb of caesium were added to the CE separation buffer to observe the capillary flow. A make-up fluid including 4 ppb Ho as an internal standard was combined with the flow from the capillary within the interface to obtain a fluid throughput high enough to maintain a continuous nebulization. Very low detection limits were achieved, 100 ppt for {sup 153}Eu and 125 ppt for {sup 158}Gd. With this optimized CE

  3. Adsorption of humic acid and Eu(III) to multi-walled carbon nanotubes. Effect of pH, ionic strength and counterion effect

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Q.H. [Chinese Academy of Sciences, Hefei (China). Key Lab. of Novel Thin Film Solar Cell; Lanzhou Univ. (China). Radiochemistry Lab.; Shao, D.D.; Hu, J.; Chen, C.L.; Wang, X.K. [Chinese Academy of Sciences, Hefei (China). Key Lab. of Novel Thin Film Solar Cell; Wu, W.S. [Lanzhou Univ. (China). Radiochemistry Lab.

    2009-07-01

    Carbon nanotubes (CNTs) have come under intense multidisciplinary study because of their unique physicochemical properties. Understanding adsorptive interactions of simultaneous humic substances (HS) and radionuclides on CNTs is critical to understand the pollution of radionuclides and the assessment of potential impact of CNTs on the behavior of HS and radionuclides. In this paper, the adsorption of humic acid (HA) and Eu(III) on multi-walled carbon nanotubes (MWCNTs) are studied as a function of pH and ionic strength. The results indicate that the adsorption of Eu(III) and HA on MWCNTs is strongly dependent on pH and ionic strength, and the presence of HA enhances Eu(III) adsorption to HA-MWCNT hybrids. The XPS analysis indicates that the functional groups of HA contribute to Eu(III) adsorption to MWCNTs. (orig.)

  4. 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

  5. Facilitated transport of titanium dioxide nanoparticles by humic substances in saturated porous media under acidic conditions

    Science.gov (United States)

    Zhang, Ruichang; Zhang, Haibo; Tu, Chen; Hu, Xuefeng; Li, Lianzhen; Luo, Yongming; Christie, Peter

    2015-04-01

    The transport behavior of titanium dioxide nanoparticles (TiO2 NPs, 30 nm in diameter) was studied in well-defined porous media composed of clean quartz sand over a range of solution chemistry under acidic conditions. Transport of TiO2 NPs was dramatically enhanced by humic substances (HS) at acidic pH (4.0, 5.0 and 6.0), even at a low HS concentration of 0.5 mg L-1. Facilitated transport of TiO2 NPs was likely attributable to the increased stability of TiO2 NPs and repulsive interaction between TiO2 NPs and quartz sands due to the adsorbed HS. The mobility of TiO2 NPs was also increased with increasing pH from 4.0 to 6.0. Although transport of TiO2 NPs was insensitive to low ionic strength, it was significantly inhibited by high concentrations of NaCl and CaCl2. In addition, calculated Derjaguin-Landau-Verwey-Overbeek (DLVO) interaction energy indicated that high energy barriers were responsible for the high mobility of TiO2 NPs, while the secondary energy minimum could play an important role in the retention of TiO2 NPs at 100 mmol L-1 NaCl. Straining and gravitational settlement of larger TiO2 NPs aggregates at 1 mg L-1 HS, pH 5.0, and 2 mmol L-1 CaCl2 could be responsible for the significant retention even in the presence of high energy barriers. Moreover, more favorable interaction between approaching TiO2 NPs and TiO2 NPs that had been already deposited on the collector resulted in a ripening-shape breakthrough curve at 2 mmol L-1 CaCl2. Overall, a combination of mechanisms including DLVO-type force, straining, and physical filtration was involved in the retention of TiO2 NPs over the range of solution chemistry examined in this study.

  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. 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

    2016-03-01

    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.

  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. Effect of humic acids on the adsorption of paraquat by goethite.

    Science.gov (United States)

    Brigante, Maximiliano; Zanini, Graciela; Avena, Marcelo

    2010-12-15

    The adsorption of the herbicide paraquat (PQ(2+)) on goethite and on the binary system humic acid-goethite has been studied in batch experiments by performing adsorption isotherms under different conditions of pH, supporting electrolyte concentration and temperature. The results were completed with capillary electrophoresis (CE) in order to measure the binding isotherm between PQ(2+) and humic acid (HA) molecules in solution. PQ(2+) adsorption is negligible on the bare goethite surface but important on the HA-goethite adsorbent. In this last case, the adsorption increases by increasing pH and decreasing electrolyte concentration. There are no significant effects of temperature on the adsorption. The adsorption takes place by direct binding of PQ(2+) to adsorbed HA molecules leading to the formation of surface species of the type goethite-HA-PQ(2+). The results are consistent with a mechanism where PQ(2+) binds negatively charged groups of HA (carboxylates and phenolates) forming ionic pairs or outer-sphere complexes. Since goethite in nature usually contains adsorbed HA molecules, it may act as a good adsorbent for cationic herbicides. This will not only benefit the deactivation of the herbicides but also reduce their leaching and transport through groundwater. Copyright © 2010 Elsevier B.V. All rights reserved.

  11. Sorption of radioactive cesium and barium ions onto solid humic acid

    Energy Technology Data Exchange (ETDEWEB)

    Celebi, O., E-mail: celebi@vt.edu [Department of Chemistry, Macromolecular Science and Engineering, Virginia Tech, Blacksburg, VA 24061 (United States); Kilikli, A. [Department of Chemistry, Middle East Technical University, 06530 Ankara (Turkey); Erten, H.N. [Department of Chemistry, Bilkent University, 06800 Bilkent, Ankara (Turkey)

    2009-09-15

    In this study, the sorption behavior of two important fission product radionuclides ({sup 137}Cs and {sup 140}Ba) onto sodium form of insolubilized humic acid (INaA) were investigated as a function of time, cation concentration and temperature, utilizing the radiotracer method. The sorption processes are well described by both Freundlich and Dubinin-Radushkevich type isotherms. Thermodynamic constants such as; free energy ({Delta}G{sub ads}), enthalpy ({Delta}H{sub ads}), entropy ({Delta}S{sub ads}) of adsorption were determined. It was found that Ba{sup 2+} was adsorbed five times more than Cs{sup +} onto structurally modified humic acid and kinetic studies indicated that adsorption behavior of both ions obey the pseudo second order rate law. The effect of pH change on sorption was also examined. FTIR and solid-state carbon NMR ({sup 13}CNMR) spectroscopic techniques were used to understand the structural changes during insolubilization process. Quantitative determination of adsorption sites was carried out using potantiometric titration.

  12. Effects of salinity and humic acid on the sorption of Hg on Fe and Mn hydroxides.

    Science.gov (United States)

    Liang, Peng; Li, Yi-Chun; Zhang, Chan; Wu, Sheng-Chun; Cui, Hao-Jie; Yu, Shen; Wong, Ming H

    2013-01-15

    The objective of this study was to investigate the influence of humic acid (HA) and salinity on adsorption of Hg on the amorphous and crystalline of iron and manganese hydroxides. The results show that the adsorption of Hg(2+) on Fe and Mn hydroxides was inhibited in marine system due to the formation of stable, nonsorbing aqueous HgCl(2) complexes in solution. Moreover, Cl(-) inhibited the Hg(2+) adsorption more severely on amorphous than crystalline hydroxides. The addition of HA inhibited Hg(2+) adsorption on Fe and Mn hydroxides in freshwater system might be attributed to the competition between Hg(2+) and HA on adsorption to Fe and Mn hydroxides. In contrast, the addition of HA promoted Hg(2+) adsorption on Fe and Mn hydroxides in the marine system, which might be due to the addition of humic acid resulted in the reaction between Cl(-) and HA, and therefore the reducing of Cl(-) promoted more Hg(2+) on Fe and Mn hydroxides. In addition, the influence of HA on Hg(2+) adsorption on Fe and Mn hydroxides are more visible for crystalline than amorphous hydroxides. Copyright © 2012 Elsevier B.V. All rights reserved.

  13. 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.

  14. 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.

  15. Light induced uptake of NO{sub 2} on submicron humic acid aerosol

    Energy Technology Data Exchange (ETDEWEB)

    Kleffmann, Joerg; Elshorbany, Yasin [Bergische Universitaet Wuppertal (Germany); Ammann, Markus; Stemmler, Konrad [Paul Scherrer Institut, Villigen (Switzerland); Bohn, Birger [Forschungszentrum Juelich (Germany); George, Christian; Ndour, Marieme [University Claude Bernard, (UCBL-CNRS), Villeurbanne (France)

    2007-07-01

    Recent field studies have demonstrated that the contribution of HONO to the OH radical production during daytime has been underestimated and indicated the existence of strong photolytic sources of HONO. A potential source is the light induced heterogeneous conversion of NO{sub 2} into HONO on humic acid surfaces, which was recently investigated on bulk surfaces. In the present laboratory study, we extended these studies to humic acid aerosols, which were generated by a nebulizer. The aerosol was transferred into a flow reactor and irradiated (300-700 nm) under controlled atmospheric conditions (humidity, NO{sub 2} concentration, etc.). HONO was detected using a selective and sensitive instrument (LOPAP), while the particle surface was quantified by a SMPS and an electrostatic precipitator. Similar to our recent study on bulk surfaces, a clearly photoinduced formation of HONO was observed, which was linear correlated with the aerosol surface and the reaction time. The experimental results are compared with the bulk study and a mechanism is presented to explain the experimental observations. In addition, the contribution to the primary production of OH radicals in the atmosphere is estimated.

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

    Energy Technology Data Exchange (ETDEWEB)

    Janot, N.; Benedetti, M. F. [Univ Paris Diderot, Lab Geochim Eaux, UMR CNRS 7154, IPGP, F-75025 Paris 13 (France); Janot, N.; Reiller, P. E. [CE Saclay, CEA DEN DANS DPC SECR, Lab Speciat Radionucleides and Mol, F-91191 Gif Sur Yvette (France); Korshin, G. V. [Univ Washington, Dept Civil and Environm Engn, Seattle, WA 98195 (United States)

    2010-07-01

    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)

  17. Effect of persulfate on the oxidation of benzotriazole and humic acid by e-beam irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Roshani, Babak, E-mail: Babak.Roshani@univ-poitiers.fr [Universite de Poitiers, CNRS, Laboratoire de Chimie et Microbiologie de l' Eau (UMR 6008), Ecole Nationale Superieure d' Ingenieurs de Poitiers, 1 rue Marcel Dore, 86022 Poitiers Cedex (France); Karpel Vel Leitner, Nathalie, E-mail: Nathalie.Karpel@univ-poitiers.fr [Universite de Poitiers, CNRS, Laboratoire de Chimie et Microbiologie de l' Eau (UMR 6008), Ecole Nationale Superieure d' Ingenieurs de Poitiers, 1 rue Marcel Dore, 86022 Poitiers Cedex (France)

    2011-06-15

    These days, the use of persulfate in advanced oxidation processes (AOPs) has gained more attention as an emerging clean and efficient technology to degrade the organic pollutants. The objective of this study was to investigate the effect of the addition of persulfate on the oxidation of benzotriazole (BT) and humic acids (HAs) by irradiation. The degradation of BT (3.7 {mu}M) was followed under the influence of persulfate addition (200-500 {mu}M) in combination with a fixed radiation dose (15 Gy) in the absence and presence of HA (5 and 20 mg/L) in deionized water. The main results obtained in this study on the degradation of BT in the presence of HA showed a different effect of S{sub 2}O{sub 8}{sup 2-} addition during irradiation, depending on whether HA are oxidized or not-oxidized. (1) An inhibitory effect of S{sub 2}O{sub 8}{sup 2-} was observed in the presence of non-oxidized HA. (2) The removal of BT was generally more important during irradiation in the presence of S{sub 2}O{sub 8}{sup 2-} when HA is pre-oxidized. This could be explained by the different structures of humic acids. These differences of structures of HA were identified by physico-chemical parameters such as the absorbance in the UV (254 nm), the fluorescence and the SUVA measurement.

  18. Electrochemical removal of Cu{sup II} in the presence of humic acid

    Energy Technology Data Exchange (ETDEWEB)

    Barbosa, Claudomiro P.; Malpass, Geoffroy R.P.; Miwa, Douglas W.; Gomes, Luciano; Motheo, Artur J., E-mail: artur@iqsc.usp.b [Universidade de Sao Paulo (USP), Sao Carlos, SP (Brazil). Inst. de Quimica; Bertazzoli, Rodnei [Universidade Estadual de Campinas (UNICAMP), SP (Brazil)

    2010-07-01

    The removal of Cu{sup II} (10 mg L{sup -1}) complexed by commercial humic acid (100 mg L{sup -1}) was studied at different current densities (30-80 mA cm{sup -2}) using a filter-press cell, Ti/Ru{sub 0.}3Ti{sub 0.7}O{sub 2} anode and stainless steel cathode. The electrolyses were performed with and without membrane separating the cell compartments [(homogeneous anionic (Nafion R117), heterogeneous cationic (Ionac MC-3470) and heterogeneous anionic (Ionac MA-3475)]. The influence of the membrane on the rate of Cu{sup II} removal was bigger for cationic membranes. Current efficiencies up to ca. 55% (Ionac MC-3470) for Cu{sup II} removal at 30 mA cm{sup -2} were obtained. By combining oxidation and reduction, 100% Cu{sup II} removal was achieved at current efficiencies of 75%. The main path for the removal is the electrostatic interaction with the anode followed by diffusion through the membrane and deposition at the cathode. Additionally, the oxidative degradation of humic acid contributes to the rate of CuI{sup I} removal. (author)

  19. Competitive sorption between imidacloprid and imidacloprid-urea on soil clay minerals and humic acids.

    Science.gov (United States)

    Liu, Weiping; Zheng, Wei; Gan, Jianying

    2002-11-06

    Soil organic matter and clay minerals are responsible for the adsorption of many pesticides. Adsorption and competitive sorption of imidacloprid on clay minerals and humic acids (HA) were determined using the batch equilibration method. The sorption coefficient of imidacloprid on humic acids was significantly higher than that on Ca-clay minerals, indicating that soil organic matter content was a more important property in influencing the adsorption of imidacloprid. Competitive sorption was investigated between imidacloprid and its main metabolite imidacloprid-urea on HA and Ca-clay minerals. The results showed that the sorption capacity of imidacloprid on clay minerals and HA was reduced in the presence of the metabolite, implying that imidacloprid-urea could occupy or block adsorption sites of imidacloprid on soil, potentially affecting the fate, transport, and bioavailability of imidacloprid in the environment. The interactions between a Ca-clay or HA-clay mixture and adsorption of imidacloprid and imidacloprid-urea were studied using IR differential spectra on thin films made of the adsorbent. The possible mechanisms were discussed from the shift of characteristic IR absorption bands of imidacloprid and imidacloprid-urea after sorption.

  20. 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.

  1. Spectroscopic and conformational properties of size-fractions acid separated from a lignite humic

    Energy Technology Data Exchange (ETDEWEB)

    Conte, P.; Spaccini, R.; Smejkalova, D.; Nebbioso, A.; Piccolo, A. [University of Naples Federico 2, Portici (Italy)

    2007-10-15

    A lignite humic acid (HA) was fractionated by preparative high performance size-exclusion chromatography (HPSEC) in seven different size-fractions. The size-fractions were characterized by cross polarization (CP) magic angle spinning (MAS) {sup 13}C NMR spectroscopy and a further analytical HPSEC elution under UV and fluorescence detection. The alkyl hydrophobic components mainly distributed in the largest molecular-size-fraction, whereas the amount of oxidized carbons increased with decreasing size of fractions. Cross polarization time (T{sub CH}) and proton spin-lattice relaxation time in the rotating frame (T{sub 1p}(H)) were measured from variable contact time (VCT) experiments. The bulk HA was characterized by the shortest T{sub CH} values and the longest T{sub 1p}(H) values which suggested, respectively, one, an aggregation of components in a large conformation that favored a fast H-C cross polarization, and, two, consequent steric hindrances that prevented fast local molecular motions and decreased proton relaxation rates. Conversely, the separated size-fractions showed longer T{sub CH} values and shorter T{sub 1p}(H) values than the bulk HA, thereby indicating that they were constituted by a larger number of mobile molecular conformations. The UV and fluorescence absorptions were both low in the large size-fractions that mainly contained alkyl carbons, whereas they increased in the olephinic- and aromatic-rich fractions with intermediate molecular-size, and decreased again in the smaller fractions which were predominantly composed by oxidized carbons. These results support the supramolecular structure of humic Substances and indicate that the observed variation in conformational distribution in humic association may be used to explain environmental processes with additional precision.

  2. The density of humic acids and humic like substances (HULIS from fresh and aged wood burning and pollution aerosol particles

    Directory of Open Access Journals (Sweden)

    E. Dinar

    2006-01-01

    Full Text Available Atmospheric aerosols play significant roles in climatic related phenomena. Size, density and shape of particles affect their fluid-dynamic parameters which in turn dictate their transport and lifecycle. Moreover, density and shape are also related to particles' optical properties, influencing their regional and global radiative effects. In the present study we have measured and compared the effective densities of humic like substances (HULIS extracted from smoke and pollution aerosol particles to those of molecular weight-fractionated aquatic and terrestrial Humic Substances (HS. The effective density was measured by comparing the electro mobility and vacuum aerodynamic diameter of aerosol particles composed of these compounds. Characterization of chemical parameters such as molecular weight, aromaticity and elemental composition allow us to test how they affect the effective density of these important environmental macromolecules. It is suggested that atmospheric aging processes increase the effective density of HULIS due to oxidation, while packing due to the aromatic moieties plays important role in determining the density of the aquatic HS substances.

  3. Model compounds of humic acid and oxovanadium cations. Potentiometric titration and EPR spectroscopy studies

    Directory of Open Access Journals (Sweden)

    Mercê Ana Lucia Ramalho

    1999-01-01

    Full Text Available The stability constants and the isotropic EPR parameters Ao (hyperfine splitting constant and g o (g value were obtained by potentiometric titrations and EPR spectroscopy, respectively, of 85%v/v aqueous solutions of model compounds of humic acids - salicylic acid (SALA - and both nitrohumic acids, a laboratory artifact - nitrosalicylic acids, 3-nitrosalicylic acid (3-NSA, 5-nitrosalicylic acid (5-NSA and 3,5-dinitrosalicylic acid (3,5-DNSA and oxovanadium cations. It was possible to record EPR spectra of those model compounds and the ion VO2+ (V(IV, and the stability constants were obtained from a solution of VO3+ (V(V, the values for the logarithms of the stability constants ranging from 12.77 ± 0.04 to 7.06 ± 0.05 for the species ML, and from 9.90 ±0.04 to 4.06 ± 0.05 for the species ML2 according to the decrease in the acidity of the carboxylic and the hydroxyl groups in the aromatic ring of the model compounds studied as the -NO2 substituents were added. Species distribution diagrams were also obtained for the equilibria studied. The EPR parameters showed that as the logarithm of the overall stability constants increase, g o values also increase, while Ao values show a tendency to decrease.

  4. Effect of Humic Acid and Ferrous Sulfate Foliar Application on Some Physiological Indices, Quantity and Quality of Grape cv. \\"Askari\\"

    Directory of Open Access Journals (Sweden)

    A. Vatankhah

    2017-02-01

    Full Text Available Application of humic acid as an organic acid derived from humus and other natural resources along with iron could be beneficial to overcoming, at least in part, the nutrients deficiencies in the grapes. In order to evaluate the effects of humic acid and iron on fruit yield and concentration of nutrient elements in the leaf of grape, a factorial experiment based on a randomized complete block design in three replications was done during growing season of 2013- 2014. The treatments included combinations of humic acid (control, 1 and 2 per thousand and ferrous sulfate (control, 1 and 2 per thousand, sprayed in two steps (i.e. before flowering and two weeks after fruit set. The results indicated that treatments significantly increased the grapes fruit yield, e.g. the maximum yield (8.27 kg per plant was obtained when 2 per thousand of iron sulfate was applied. The above treatments significantly affected nitrogen, iron, zinc and copper content of leaves. Foliar application of ferrous sulfate increased leaf iron concentration, i.e. the highest (189.6 mg per kg tissue iron content was observed at the presence of 2 per thousand ferrous sulfate treatment.  Positive correlations were observed between the leaf iron concentration with fruit yield, cluster weight, berry diameter, leaf chlorophyll concentration and TSS of fruit. Hence, foliar application of humic acid and iron sulfate (e.g. each at a two per thousand concentrations in vineyards might be effective in increasing quality and quantity of grapes.

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

    Energy Technology Data Exchange (ETDEWEB)

    Steely, Sarah [School of Natural Science, Hampshire College, 869, West Street, Amherst, MA 01002 (United States); Amarasiriwardena, Dulasiri [School of Natural Science, Hampshire College, 869, West Street, Amherst, MA 01002 (United States)]. E-mail: dula@hampshire.edu; Xing Baoshan [Department of Plant, Soil, and Insect Sciences, University of Massachusetts, Amherst, MA 01003 (United States)

    2007-07-15

    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 {mu}g kg{sup -1}) and the apple orchard (69 {mu}g kg{sup -1}) had considerably higher surface Sb levels than the control site (<1.5 {mu}g kg{sup -1}), and Sb was confined to the top {approx}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.

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

    Science.gov (United States)

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

    2017-11-01

    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 reduced Ni uptake by E. crypticus in the soil-solution test system. Median lethal effect concentrations were calculated based on total dissolved Ni concentrations (LC50[Ni]), free Ni ion activity (LC50{Ni2+ }), and Ni body concentrations (LC50Body-Ni ). The LC50[Ni] values increased with increasing DOC levels and decreased with exposure time (4, 7, and 10 d). Humic acid exerted a greater protective effect on Ni toxicity than fulvic acid, but the protective effects decreased with prolonged exposure time. The LC50{Ni2+ } values also decreased with exposure time but were almost constant with variation in DOC levels, indicating that the protective effect of DOC is mainly through complexation with free Ni ions to reduce Ni bioavailability. The LC50Body-Ni value was independent of DOC concentration and exposure time, with an estimated overall value of 22.1 µg/g dry weight. The present study shows that body concentration could serve as an effective indicator for predicting Ni toxicity with variations in the exposure environment (e.g., DOC) and exposure time. Environ Toxicol Chem 2017;36:3019-3027. © 2017 SETAC. © 2017 SETAC.

  7. STXM and LSLM investigation of Eu(III) induced humic acid colloid aggregation

    Energy Technology Data Exchange (ETDEWEB)

    Plaschke, M; Rothe, J; Klenze, R [Forschungszentrum Karlsruhe, Institut fuer Nukleare Entsorgung, Postfach 3640, D-76021 Karlsruhe (Germany); Wissler, J; Naber, A, E-mail: plaschke@ine.fzk.d [Universitaet Karlsruhe, Institut fuer Angewandte Physik, Wolfgang-Gaede-Strasse 1, D-76131 Karlsruhe (Germany)

    2009-09-01

    Humic acids (HA) are potentially important in binding traces of actinides or lanthanides, thus affecting their transport in aquatic systems. Eu(III) induced HA colloid aggregation has been investigated by a combination of Scanning Transmission X-ray Microscopy (STXM) and Laser Scanning Luminescence Microscopy (LSLM). Both methods reveal the same aggregate morphology - optically dense zones embedded in a matrix of less dense material observed by STXM correspond to areas with increased Eu(III) luminescence yield in the LSLM micrographs. From these comparative measurements we infer the enrichment of Eu(III) cations in the optically dense zones. These areas also exhibit a C 1s-NEXAFS signature strongly differing from the signal extracted from the less dense areas. Spectral filtering of Eu(III) luminescence lines corresponding to valence transitions affected by organic acid complexation indicates that Eu(III) cations are more strongly bound in the dense zones.

  8. Enhanced degradation of metalaxyl in Gley Humic and Dark Red Latosol

    Directory of Open Access Journals (Sweden)

    S. Papini

    2000-06-01

    Full Text Available Enhanced degradation of the fungicide metalaxyl was investigated in two soils: a gley humic (GH and a Dark Red Latosol (LE, collected at sites never exposed to the fungicide. The soil samples were treated with successive applications of metalaxyl as a commercial formulation and 14C-metalaxyl in laboratory. Metalaxyl biodegradation was analyzed during 63 days by means of radiometric techniques to verify biomineralization and degradation product formation from the applied 14C-metalaxyl. Although biomineralization (maximum of 14 and 8% in the GH and LE soils, respectively, and partial degradation (about 32 and 48%, respectively were detected in both soils, enhanced degradation was verified only in the GH soil. Results proved that metalaxyl behaves differently in soils.

  9. Humic acid decreases acute toxicity and ventilation frequency in eastern rainbowfish (Melanotaenia splendida splendida) exposed to acid mine drainage.

    Science.gov (United States)

    Holland, Aleicia; Duivenvoorden, Leo J; Kinnear, Susan H W

    2014-12-01

    Acid mine drainage (AMD) is a global problem leading to the acidification of freshwaters, as well as contamination by heavy metals. The ability of humic substances (HS) such as humic acid (HA) to decrease toxicity of heavy metals is widely known, whereas limited studies have examined the ability of HS to decrease toxicity linked with multiple stressors such as those associated with AMD. This study investigated the ability of HA to decrease acute toxicity defined as morbidity and ventilation frequency (measured via the time elapsed for ten operculum movements) in eastern rainbowfish (Melanotaenia splendida splendida) exposed to the multiple stressors of AMD-driven heavy metal concentrations, together with low pH. Water from the Mount Morgan open pit (a now closed gold and copper mine site), located at Mount Morgan, Central Queensland, Australia, was used as the AMD source. Fish were exposed to zero per cent (pH 7.3), two per cent (pH 6.7), three per cent (pH 5.7) and four per cent (pH 4.6) AMD in the presence of 0, 10 and 20mg/L Aldrich Humic Acid (AHA) over 96h. HA was shown to significantly decrease the acute toxicity of AMD and its adverse effects on ventilation frequency. These results are important in showing that HA can influence toxicity of metal mixtures and low pH, thus indicating a potential role for HA in decreasing toxicity of multiple environmental stressors more widely, and possible value as a rehabilitation aid. Copyright © 2014 Elsevier Inc. All rights reserved.

  10. Humic substances increase survival of freshwater shrimp Caridina sp. D to acid mine drainage.

    Science.gov (United States)

    Holland, Aleicia; Duivenvoorden, Leo J; Kinnear, Susan H W

    2013-02-01

    Humic substances (HS) are known to decrease the toxicity of heavy metals to aquatic organisms, and it has been suggested that they can provide buffering protection in low pH conditions. Despite this, little is known about the ability for HS to increase survival to acid mine drainage (AMD). In this study, the ability of HS to increase survival of the freshwater shrimp (Caridina sp. D sensu Page et al. in Biol Lett 1:139-142, 2005) to acid mine drainage was investigated using test waters collected from the Mount Morgan open pit in Central Queensland with the addition of Aldrich humic acid (AHA). The AMD water from the Mount Morgan open pit is highly acidic (pH 2.67) as well as contaminated with heavy metals (1780 mg/L aluminum, 101 mg/L copper [Cu], 173 mg/L manganese, 51.8 mg/L zinc [Zn], and 51.8 mg/L iron). Freshwater shrimp were exposed to dilutions in the range of 0.5 % to 5 % AMD water with and without the addition of 10 or 20 mg/L AHA. In the absence of HS, all shrimp died in the 2.5 % AMD treatment. In contrast, addition of HS increased survival in the 2.5 % AMD treatment by ≤66 % as well as significantly decreased the concentration of dissolved Cu, cobalt, cadmium, and Zn. The decreased toxicity of AMD in the presence of HS is likely to be due to complexation and precipitation of heavy metals with the HS; it is also possible that HS caused changes to the physiological condition of the shrimp, thus increasing their survival. These results are valuable in contributing to an improved understanding of potential role of HS in ameliorating the toxicity of AMD environments.

  11. 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.

  12. Measurement of humic and fulvic acid concentrations and dissolution properties by a rapid batch procedure

    Energy Technology Data Exchange (ETDEWEB)

    Van Zomeren, A.; Comans, R.N.J. [ECN Biomass, Coal and Environmental Research, Petten (Netherlands)

    2007-08-29

    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 batch method to measure humic (HA) and fulvic (FA) acid concentrations and dissolution properties in both solid and aqueous samples. The method is compared with the conventional procedures and is shown to substantially facilitate HS concentration measurements, particularly for applications such as geochemical modeling where HS purification is not required. The new method can be performed within 1.5-4 h per sample and multiple samples can be processed simultaneously, while the conventional procedures typically require approximately 40 h for a single sample. In addition, specific dissolution properties of HS are identified and are consistent with recent views on the molecular structure of HS that emphasize molecular interactions of smaller entities over distinct macromolecular components. Because the principles of the new method are essentially the same as those of generally accepted conventional procedures, the identified HA and FA properties are of general importance for the interpretation of the environmental occurrence and behavior of HS.

  13. Fourier transform surface-enhanced Raman spectra of fulvic acid from weathered coal adsorbed on gold electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Wang, T.; Xiao, Y.J.; Yang, J.H.; Chase, H.A. [University of Cambridge, Cambridge (United Kingdom). Dept. of Chemical Engineering

    1999-08-01

    Surface-enhanced Raman spectroscopy was used to demonstrate that fulvic and humic acids can be readily adsorbed on gold surfaces mainly via physical adsorption. Chemically enhanced effects also play a minor role since the surface-enhanced Raman spectroscopic (SERS) signals of a few of specific groups in humic substances are selectively enhanced in some cases. Metal ions in solutions have little influence on the SERS spectra of fulvic acid and it implies that the binding sites of the fulvic acid to metal ions are located at considerable distance from the gold surface. The data show that humic substances are adsorbed to a gold surface via their hydrophobic regions whilst their active sites remain available. SERS spectroscopy on gold electrodes shows potential for in situ observation of humic substances in aqueous environment pertinent to their environmental roles.

  14. Influence of humic acid on the colloidal stability of surface-modified nano zero-valent iron.

    Science.gov (United States)

    Dong, Haoran; Lo, Irene M C

    2013-01-01

    To enhance colloidal stability of nano zero-valent iron (NZVI) used for groundwater remediation, the surfaces of such NZVI can be modified via coating with organic stabilizers. These surface stabilizers can electrostatically, sterically, or electrosterically stabilize NZVI suspensions in water, but their efficacy is affected by the presence of humic acid (HA) in groundwater. In this study, the effect of HA on the colloidal stability of NZVI coated with three types of stabilizers (i.e., polyacrylic acid (PAA), Tween-20 and starch) was evaluated. Differing stability behaviors were observed for different surface-modified NZVIs (SM-NZVI) in the presence of HA. Fluorescence spectroscopic analysis probed the possible interactions at the SM-NZVI-HA interface, providing a better understanding of the effect of HA on SM-NZVI stability. The adsorption of HA on the surface of PAA-modified NZVI via complexation with NZVI (rather than the PAA stabilizer) enhanced the electrosteric repulsion effect, increasing the stability of the particles. However, for NZVI modified with Tween-20 or starch, HA could interact with the surface stabilizer and apparently play a "bridge" role among the particles, which might induce aggregation of the particles. Therefore, the stability behavior of NZVI modified with Tween-20 or starch might have resulted from the combined effect of "bridging" and "electrosteric" exerted by HA. Copyright © 2012 Elsevier Ltd. All rights reserved.

  15. 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 strong...

  16. 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

  17. 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

  18. Interaction of fullerene (C60) nanoparticles with humic acid and alginate coated silica surfaces: measurements, mechanisms, and environmental implications.

    Science.gov (United States)

    Chen, Kai Loon; Elimelech, Menachem

    2008-10-15

    The deposition kinetics of fullerene (C60) nanoparticles onto bare silica surfaces and surfaces precoated with humic acid and alginate are investigated over a range of monovalent (NaCI) and divalent (CaCl2) salt concentrations using a quartz crystal microbalance. Because simultaneous aggregation of the fullerene nanoparticles occurs, especially at higher electrolyte concentrations, we normalize the observed deposition rates by the corresponding favorable (transport-limited) deposition rates to obtain the attachment efficiencies, alpha. The deposition kinetics of fullerene nanoparticles onto bare silica surfaces are shown to be controlled by electrostatic interactions and van der Waals attraction, consistent with the classical particle deposition behavior where both favorable and unfavorable deposition regimes are observed. The presence of dissolved humic acid and alginate in solution leads to significantly slower deposition kinetics due to steric repulsion. Precoating the silica surfaces with humic acid and alginate exerts similar steric stabilization in the presence of NaCl. In the presence of CaCl2, the deposition kinetics of fullerene nanoparticles onto both humic acid- and alginate-coated surfaces are relatively high, even at relatively low (0.3 mM) calcium concentration. This behavior is attributed to the macromolecules undergoing complex formation with calcium ions, which reduces the charge and steric influences of the adsorbed macromolecular layers.

  19. Using solid-phase microextraction to determine partition coefficients to humic acids and bioavailable concentrations of hydrophobic chemicals

    Energy Technology Data Exchange (ETDEWEB)

    Ramos, E.U.; Meijer, S.N.; Vaes, W.H.J.; Verhaar, H.J.M.; Hermens, J.L.M. [Utrecht Univ. (Netherlands). Research Inst. of Toxicology

    1998-11-01

    In the current study, the suitability of negligible depletion solid-phase microextraction (nd-SPME) to determine free fractions of chemicals in aquatic environments was explored. The potential interferences of the dissolved matrix (i.e., humic acids) with the SPME measurements were tested. Results show that nd-SPME measures only the freely dissolved fraction and that the measurements are not disturbed by the humic acids. In addition, nd-SPME was used to determine partition coefficients between dissolved organic carbon and water for four hydrophobic chemicals. Obtained values are in excellent agreement with previously reported data. Finally, the bioaccumulation of hexachlorobenzene and PCB 77 to Daphnia magna was determined in the presence and absence of humic acids. The bioconcentration factors (BCF) were calculated based on total as well as on free concentration. Lower BCF values are obtained in the presence of humic acids using total concentrations, whereas equal BCFs are found using free concentrations measured with nd-SPME. Therefore, the authors can conclude that negligible depletion SPME is a good technique to determine bioavailable concentrations of hydrophobic chemicals in aquatic environments.

  20. Accurate quantification of PAHs in water in the presence of dissolved humic acids using isotope dilution mass spectrometry.

    Science.gov (United States)

    Bercaru, Ofelia; Ulberth, Franz; Emons, Hendrik; Vandecasteele, Carlo

    2006-03-01

    The effect of dissolved humic acids on the recovery of PAHs from water samples has been investigated using a commercially available humic acid preparation as colloid model and a mixture containing the 16 EPA PAHs. The presence of humic acid reduced the extraction efficiency down to between 10 and 75%. An analytical protocol was therefore developed for the accurate determination of PAHs in the presence of humic acids based on isotope dilution mass spectrometry. The procedure compensates for losses due to sorption of PAHs and can be used for the determination of the total PAH concentration in water, i.e. dissolved PAHs plus PAHs adsorbed on colloids. To obtain reliable estimates it is essential to allow a certain time for equilibration between the isotope spike and the aqueous matrix which may vary between 5 and 24 h, in correlation with the water solubility of PAHs. The protocol allows one to recover the 16 PAHs studied at 94 to 105%. The expanded uncertainty of the measurements was 5-7% for all PAHs. Liquid-liquid extraction and solid-phase extraction in combination with the developed isotope dilution protocol performed equally well for the quantification of PAHs from water samples rich in colloidal material.

  1. Accurate quantification of PAHs in water in the presence of dissolved humic acids using isotope dilution mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Bercaru, Ofelia; Ulberth, Franz; Emons, Hendrik [Institute for Reference Materials and Measurements (IRMM), European Commission, Joint Research Centre, Geel (Belgium); Vandecasteele, Carlo [Katholieke Universiteit Leuven, Department of Chemical Engineering, Heverlee (Belgium)

    2006-03-15

    The effect of dissolved humic acids on the recovery of PAHs from water samples has been investigated using a commercially available humic acid preparation as colloid model and a mixture containing the 16 EPA PAHs. The presence of humic acid reduced the extraction efficiency down to between 10 and 75%. An analytical protocol was therefore developed for the accurate determination of PAHs in the presence of humic acids based on isotope dilution mass spectrometry. The procedure compensates for losses due to sorption of PAHs and can be used for the determination of the total PAH concentration in water, i.e. dissolved PAHs plus PAHs adsorbed on colloids. To obtain reliable estimates it is essential to allow a certain time for equilibration between the isotope spike and the aqueous matrix which may vary between 5 and 24 h, in correlation with the water solubility of PAHs. The protocol allows one to recover the 16 PAHs studied at 94 to 105%. The expanded uncertainty of the measurements was 5-7% for all PAHs. Liquid-liquid extraction and solid-phase extraction in combination with the developed isotope dilution protocol performed equally well for the quantification of PAHs from water samples rich in colloidal material. (orig.)

  2. Action of humic acid on promotion of cucumber shoot growth involves nitrate-related changes associated with the root-to-shoot distribution of cytokinins, polyamines and mineral nutrients.

    Science.gov (United States)

    Mora, Verónica; Bacaicoa, Eva; Zamarreño, Angel-Maria; Aguirre, Elena; Garnica, Maria; Fuentes, Marta; García-Mina, José-Maria

    2010-05-15

    Numerous studies have reported the ability of humic substances to increase shoot growth in different plant species cultivated under diverse growth conditions. However, the mechanism responsible for this effect of humic substances is poorly understood. It is possible that the shoot promoting effect of humic substances involves a primary effect on root H(+)-ATPase activity and nitrate root-shoot distribution that, in turn, causes changes in the root-shoot distribution of certain cytokinins, polyamines and abscisic acid, thus affecting shoot growth. We investigated this hypothesis in the present study. The results showed that the root application of a purified humic acid causes a significant increase in shoot growth that is associated with an enhancement in root H(+)-ATPase activity, an increase in nitrate shoot concentration, and a decrease in roots. These effects were associated with significant increases in the shoot concentration of several cytokinins and polyamines (principally putrescine), concomitant with decreases in roots. Likewise, these changes in the root-shoot distribution of diverse active cytokinins correlated well to significant changes in the root-shoot distribution of several mineral nutrients. These results, taken together, indicate that the beneficial effects of humic substances on shoot development in cucumber could be directly associated with nitrate-related effects on the shoot concentration of several active cytokinins and polyamines (principally putrescine). (c) 2010 Elsevier GmbH. All rights reserved.

  3. Adsorption of insecticidal Cry1Ab protein to humic substances. 2. Influence of humic and fulvic acid charge and polarity characteristics.

    Science.gov (United States)

    Tomaszewski, Jeanne E; Madliger, Michael; Pedersen, Joel A; Schwarzenbach, René P; Sander, Michael

    2012-09-18

    Assessing the fate and potential risks of transgenic Cry proteins in soils requires understanding of Cry protein adsorption to soil particles. The companion paper provided evidence that patch-controlled electrostatic attraction (PCEA) and the hydrophobic effect contributed to Cry1Ab protein adsorption to an apolar humic acid (HA). Here, we further assess the relative importance of these contributions by comparing Cry1Ab adsorption to seven humic substances varying in polarity and charge, at different solution pH and ionic strength, I. Cry1Ab adsorption to relatively apolar HAs at I = 50 mM exhibited rapid initial rates, was extensive, and was only partially reversible at pH 5-8, whereas adsorption to more polar fulvic acids was weak and reversible or absent at pH >6. The decrease in adsorption with increasing HS polarity at all tested pH strongly supports a large contribution from the hydrophobic effect to adsorption, particularly at I = 50 mM when PCEA was effectively screened. Using insect bioassays, we further show that Cry1Ab adsorbed to a selected HA retained full insecticidal activity. Our results highlight the need to consider adsorption to soil organic matter in models that assess the fate of Cry proteins in soils.

  4. 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

  5. Evaluating the efficiency of humic acid to remove micro-organisms from denture base material.

    Science.gov (United States)

    Meriç, Gökçe; Güvenir, Meryem; Süer, Kaya

    2016-09-01

    To evaluate the efficiency of humic acid substances on removing micro-organisms from denture base materials. Old denture wearer needs effective, easy-use and safe denture-cleaning material. Square-shaped, heat-polymerised acrylic resin specimens (n = 550) were prepared and divided into five groups (n = 110 for each) corresponding to the microbial contamination (Candida albicans, Staphylococcus aureus, Bacillus cereus, Enterococcus faecalis, Pseudomonas aeruginosa). Contaminated specimens were randomly assigned to the application of five different denture-cleaning agents as follows (n = 20 for each): Kloroben, Corsodyl, Steradent, Corega, experimental solution with humic acid. Ten specimens were assessed as an experimental control carried out simultaneously for the treatment groups for each micro-organism. It was divided into two groups: negative control and positive control (n = 5 for each). All acrylic specimens were incubated 37°C for 24 h (for bacterial strains) and 37°C for 48 h (for yeast strains). After incubation period, all brain-heart infusion broths (BHI) which contain disinfectant acrylic specimens were cultured on 5% sheep blood agar (for bacteria) and Sabouraud dextrose agar (SDA) for yeast using loop. The numbers of colony-forming units per millilitre (CFU/ml) were calculated. The results were analysed by Mann-Whitney U-test and Kruskal-Wallis tests (p = 0.05). Corsodyl and Kloroben completely eliminated the adherence of all investigated micro-organisms (100%) and showed the highest removal activity compared with other cleaning agents (p < 0.05). There was no statistically significant difference between Corsodyl and Kloroben (p ≥ 0.05), and there was no statistically significant difference between Corega, Steradent and experimental solution (p ≥ 0.05). Humic acid could be used as an alternative 'natural' solution for denture-cleaning agent. © 2014 John Wiley & Sons A/S and The Gerodontology Association. Published by John Wiley

  6. Combined effects of titanium dioxide and humic acid on the bioaccumulation of cadmium in Zebrafish

    Energy Technology Data Exchange (ETDEWEB)

    Hu Xialin [State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092 (China); Key Laboratory of Yangtze River Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092 (China); Chen Qiqing; Jiang Lei; Yu Zhenyang; Jiang Danlie [State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092 (China); Yin Daqiang, E-mail: yindq@tongji.edu.cn [State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092 (China)

    2011-05-15

    The combined effects of titanium dioxide (TiO{sub 2}) nanoparticles and humic acid (HA) on the bioaccumulation of cadmium (Cd) in Zebrafish were investigated. Experimental data on the equilibrium Cd bioaccumulation suggest that only the dissolved Cd effectively contributed to Cd bioaccumulation in HA solutions whereas both the dissolved and TiO{sub 2} associated Cd were accumulated in TiO{sub 2} or the mixture of HA and TiO{sub 2} solutions, due likely to the additional intestine uptake of the TiO{sub 2}-bound Cd. The equilibrium Cd bioaccumulation in the mixed system was comparable to that in the corresponding HA solutions, and significantly lower than that in the corresponding TiO{sub 2} solutions (n = 3, p < 0.05). The presence of either HA or TiO{sub 2} (5-20 mg L{sup -1}) in water slightly increased the uptake rate constants of Cd bioaccumulation whereas combining HA and TiO{sub 2} reduced the uptake rate constants. - Graphical abstract: Both titanium dioxide (TiO{sub 2}) and mixtures of TiO{sub 2} and humic acid (HA) facilitate the bioaccumulation of Cd in Zebrafish. The asterisk denotes significant differences of the values in solution with and without matrices. Significant differences between the test systems with 5 mg L{sup -1} HA, 5 mg L{sup -1} TiO{sub 2} and [5 + 5] mg L{sup -1} HA and TiO{sub 2} as well as 10 mg L{sup -1} HA, 10 mg L{sup -1} TiO{sub 2} and [10 + 10] mg L{sup -1} HA and TiO{sub 2} are indicated by different letters. C and C{sub 0} represent dissolved Cd concentrations (a) and Cd bioaccumulation (b) in solutions with and without matrices, respectively. Display Omitted Highlights: > TiO{sub 2} facilitated the bioaccumulation of Cd in Zebrafish. > TiO{sub 2} associated Cd added to Cd bioaccumulation in TiO{sub 2} or mixtures of HA and TiO{sub 2}. > Coexistence with HA reduced Cd bioaccumulation in TiO{sub 2} solutions. > HA or TiO{sub 2} increased the bioaccumulation rate constants whereas mixtures not. - Titanium dioxide in the aquatic

  7. 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(-), SO4(2-)and NO3(-) with some inhibition effect by CO3(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.

  8. [Effects of different managements on soil humic acid structural features in chestnut soil on typical Leymus chinensis steppe, Inner Mongolia, China].

    Science.gov (United States)

    Li, Guang-Jun; Lü, Yi-Zhong; Li, Bao-Guo

    2009-06-01

    Grazing has a lot of effects on grassland soil properties. The objective of the present study is to investigate the effects of different managements on soil humic acids. Soil samples were collected from the surface soil of four adjacent plots ( I , II , III and IV) at a long-term experiment site of the Inner Mongolia Grassland Ecosystem Research Station (IMGERS), the Chinese Academy of Sciences. The structure features of humic acids were investigated by cross-polarization magic angle spinning 13C-nuclear magnetic resonance spectroscopy (CP/MAS 13C-NMR), FTIR and elemental analysis. The results indicated that the humic acid extracted from the grazing plots were characterized by a higher degree of humification, including loss of polysaccharides, decrease in lignin content and increase in aromaticity. Compared with the humic substances from the grazing plots, the humic substances from fenced plots showed a lower degree of humification and were considerably more aliphatic in nature.

  9. 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.

  10. 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

  11. 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

  12. Spectroscopic characterization of the competitive binding of Eu(III), Ca(II), and Cu(II) to a sedimentary originated humic acid

    Energy Technology Data Exchange (ETDEWEB)

    Marang, L.; Reiller, P.E. [CEA Saclay, Nucl Energy Div, DPC SECR, Lab Speciat Radionucleides and Mol, 91 - Gif sur Yvette (France); Marang, L.; Benedetti, M.F. [Univ Paris 07, Lab Geochim Eaux, IPGP UMR CNRS 7154, F-75205 Paris 13 (France); Eidner, S.; Kumke, M.U. [Univ Potsdam, Inst Chem, D-14476 Potsdam (Germany)

    2009-06-15

    The competition between REE, alkaline earth and d-transition metals for organic matter binding sites is still an open field of research; particularly, the mechanisms governing these phenomena need to be characterized in more detail. In this study, we examine spectroscopically the mechanisms of competitive binding of Eu(III)/Cu(II) and Eu(III)/Ca(II) pair to Gorleben humic acid (HA), as previously proposed in the framework of the NICA-Donnan model. The evolution of time-resolved laser induced luminescence spectra of humic-complexed Eu(Ill) showed two strikingly different environments for a comparable bound proportion for Cu(II) and Ca(II). Cu(II) seems to compete more effectively with Eu(III) inducing its release into the Donnan phase, and into the bulk solution as free Eu{sup 3+}. This is evidenced both by the shapes of the spectra and by the decrease in the luminescence decay times. In contrast with that, Ca(II) induces a modification of the HA structure, which enhances the luminescence of humic-bound Eu(III), and causes a minor modification of the chemical environment of the complexed rare earth ion. (authors)

  13. 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 (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.

  14. Photodynamic processes in Cm(III)/Tb(III) humic and fulvic acid complexes

    Energy Technology Data Exchange (ETDEWEB)

    Claret, F. [CEA/DEN/DPC/SECR/Laboratoire de Speciation des Radionucleides et des Molecules, CE Saclay, Batiment, 391, BP 11, F-91191 Gif-sur-Yvette CEDEX (France)]|[Institut fuer Nukleare Entsorgung, Forschungszentrum Karlsruhe, P.O. Box 3640, 76021 Karlsruhe (Germany); Rabung, T.; Klenze, R.; Kim, J.I.; Buckau, G. [Institut fuer Nukleare Entsorgung, Forschungszentrum Karlsruhe, P.O. Box 3640, 76021 Karlsruhe (Germany); Kumke, M. [Institut fuer Chemie, Universitaet Potsdam, Karl-Liebknecht-Str. 24- 25, 14476 Potsdam-Golm (Germany); Stumpf, T.; Fanghaenel, T. [Ruprecht-Karls-Universitaet Heidelberg, Physikalisch- Chemisches Institut, Im Neuenheimer Feld 253, 69120 Heidelberg (Germany)

    2005-07-01

    Full text of publication follows: Photodynamic processes of the Cm(III) and Tb(III) complexed with different humic (HA) and fulvic acids (FA) are investigated with respect to the intrinsic fluorescence of humic substances (HS = FA and HA fractions) as well as to the luminescence of Cm(III) and Tb(III). The luminescence of Cm(III) and Tb(III) is shown to be the sum of two contributions: 1) direct excitation of the complexed metal ion and 2) indirect excitation via energy transfer from the HS (sensitization). For Cm(III), the HS-complexation leads to a red shift of the excitation peak relative to the non-complexed Cm(III) ion. The sensitization based contribution to the Cm(III) and Tb(III) emission spectra in HS complexes, resemble the fluorescence excitation spectra of the HS. Thereby, Cm(III) and Tb(III) HS complex luminescence intensities differ from that of the non-complexed metal ion and varies from one HS to another. For the complexed metal ions, the luminescence sensitization is strongly influenced by the origin of the HS, whereas this is not the case for direct excitation. Moreover, the FA and HA fractions of HS of the same origin show very different sensitization capabilities. Thus, the photophysical properties of the HS play a key role in the luminescence sensitization, which can be attributed to an energy transfer (ET) from HS centered excited states to the bound Cm(III) or Tb(III) ions. The sensitization is directly related to both electronic and structural properties of HS, the latter because the efficiency of the energy transfer is strongly dependent on the distance between donor and acceptor. In addition, depending on the relative energy of the electronic states of HS and metal ions involved in the ET, an energy back-transfer from the metal ion back to HS takes place. The combination of energy transfer and back-transfer results in the non-monoexponential decay of Cm(III) and Tb(III) luminescence when complexed by HS. The extent of the energy back

  15. New Insights on the Simultaneous Removal by Adsorption on Organoclays of Humic Acid and Phenol

    Directory of Open Access Journals (Sweden)

    Emese Szabó

    2016-01-01

    Full Text Available The exploitation of thermal water as a heat source in houses and apartments (during winter is a widely used alternative to natural gas. However, this type of water may contain organic contaminants, which must be removed before releasing the used water into rivers and lakes. Because of the presence of a wide range of pollutants (including phenolic compounds and humates, efficient, cheap removal processes are needed. In order to demonstrate their capability in thermal water cleaning, clay minerals were applied for the removal of phenol and humic acid via adsorption. To determine the most efficient removal strategy for the aforementioned pollutants, the following parameters were investigated: the type of the clay mineral, the organophilization strategy (in situ or pre-organophilization, and the individual or simultaneous removability of the model pollutants. The current study revealed that the applied low cost, in situ prepared clay mineral adsorbents are applicable in the removal of pollutants from thermal water.

  16. Layer structured graphite oxide as a novel adsorbent for humic acid removal from aqueous solution.

    Science.gov (United States)

    Hartono, Tri; Wang, Shaobin; Ma, Qing; Zhu, Zhonghua

    2009-05-01

    Layer structured graphite oxide (GO) was prepared from graphite using the Hummers-Offeman method, characterised using N(2) adsorption, XRD, XPS, SEM(TEM), and FT-IR, and tested for humic acid (HA) adsorption in aqueous solution. XRD, XPS, and FT-IR measurements indicate the formation of layered structure with strong functional groups of GO. It is also found that the GO exhibits strong and much higher adsorption capacity of HA than graphite. The maximum adsorption capacity of the GO from the Langmuir isotherm is 190 mg/g, higher than activated carbon. For the adsorption, several parameters will affect the adsorption such as solid loading and pH. HA adsorption will decrease with increasing pH and an optimum GO loading is required for maximum adsorption.

  17. 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.

  18. 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.

  19. Effect of humic acid on the uranium(VI) sorption onto phyllite and its mineralogical constituents

    Energy Technology Data Exchange (ETDEWEB)

    Schmeide, K.; Jander, R.; Heise, K.H.; Bernhard, G. [Forschungszentrum Rossendorf e.V. (FZR) (Germany). Inst. fuer Radiochemie

    1999-06-01

    The effect of humic acid (HA) on the uranium(VI) sorption onto phyllite and onto its individual main mineralogical constituents, muscovite, albite, and quartz was studied in air-equilibrated batch experiments in the pH range of 3.5 to 9.5. The uranyl(VI) and HA concentration was 1 x 10{sup -6}M and 5 mg/L, respectively. The ionic strength was held constant at 0.1 M (NaClO{sub 4} solution). A size fraction of 63 to 200 {mu}m of the solids was used, the mass loading was 12.5 g/L, and the experimental volume was 40 mL. (orig.)

  20. A humic substance analogue AQDS stimulates Geobacter sp. abundance and enhances pentachlorophenol transformation in a paddy soil.

    Science.gov (United States)

    Chen, Manjia; Tong, Hui; Liu, Chengshuai; Chen, Dandan; Li, Fangbai; Qiao, Jiangtao

    2016-10-01

    Soil humic substances can be used as redox mediators in accelerating the biotransformation of organic pollutants, and humus-respiring bacteria are widely distributed in soils. However, the impact of humic substances on the soil microbial community during the biotransformation of organic pollutants is expected to be crucial while remains to be unclear. In this study, the biostimulation of indigenous microbial communities and the consequent effects on anaerobic transformation of pentachlorophenol (PCP) by a model humic substance, anthraquinone-2,6-disulfonate (AQDS), were systematically investigated in a paddy soil. The addition of AQDS was observed to increase the production of HCl-extractable Fe(II) and enhance the PCP transformation rates consequently. The pseudo-first-order rate constants of the PCP transformation showed a positive exponential relationship with the AQDS dosage. The terminal restriction fragment length polymorphism (T-RFLP) results indicated the substantial effect of added AQDS on soil microbial community. The enhanced abundance of Geobacter sp. was disclosed to be most critical for accelerated PCP transformation when with AQDS, in which Geobacter sp. functioned for promoting the generation of active Fe(II) and consequently enhancing the PCP transformation rates. The transformation rates of PCP were exponentially correlated with the abundance of Geobacter sp. positively. The findings are expected to improve the understanding of diversity and ubiquity of microorganisms in humic substances-rich soils for accelerating the transformations of soil chlorinated pollutants. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. 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.

  2. 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.

  3. The effect of the humic acid and herbal additive supplement on carcass parameters of broiler chicken

    Directory of Open Access Journals (Sweden)

    Veronika Pistová

    2016-10-01

    Full Text Available The aim of this study was the assessment of an influence of dietary humic acids and dietary herbal additive (clove (Syzygium aromaticum, lavender (Lavendula angustifolia and black pepper (Piper nigrum L. on carcass parameters of Ross 308 broiler chicken (n=60.  Broiler chicken were divided into 3 treatments (n=20. The chicken of the control group were fed with complete feed mixtures without any additives. Chicken in treatments T1 were fed a diet containing 1% of humic acid and drank a water containing 150 mg/l of dietary herbal additive, chicken in treatments T2 were fed with complete feed mixture without any additives and drank a water containing 150 mg/l of herbal additive. The carcass weight, weight of heart, liver, gizzard and neck without skin and carcass yield were evaluated. The carcass weight was in the treatment T2 statistically significantly higher (P≤0.05 in compare with control group (values in the order of the groups: 1293.1±179.0; 1429.3±156.1 and 1531.6±282.3 g±SD. In the treatment T1 was weight of gizzard (43.7±7.5 g±SD significantly higher (P≤0.05 compared to control group (34.9±5.2 g±SD. In the treatment T2 was weight of liver (72.8±11.4 g±SD significantly higher (P≤0.05 compared to control group (49.3±10.3 g±SD. In indicators weight of heart, weight of neck without skin and carcass yield were recorded nonsignificant different (P≥0.05 compared to the control group

  4. Influence of humic acid on neptunium(V) sorption and diffusion in Opalinus Clay

    Energy Technology Data Exchange (ETDEWEB)

    Froehlich, D.R.; Amayri, S.; Drebert, J.; Reich, T. [Mainz Univ. (Germany). Inst. of Nuclear Chemistry

    2013-11-01

    The influence of {sup 14}C-labeled M42 humic acid (HA) on the interaction between neptunium(V) and natural clay rock (Opalinus Clay (OPA), Switzerland) has been investigated in batch sorption and diffusion experiments under ambient air conditions. The effect of 10 mg/L HA on the diffusion of 8 {mu}M Np(V) in OPA has been investigated in synthetic OPA pore water (pH 7.6, I = 0.4M) for the first time. Batch sorption experiments as a function of solid-to-liquid ratio (4-20 g/L) were performed under same experimental conditions to compare distribution coefficients obtained from both diffusion and sorption experiments. These experiments showed only a slight influence of HA on Np(V) uptake by OPA in both cases and provided comparable distribution coefficients (presence of HA: K{sub d} = 22-32 L/kg, absence of HA: K{sub d} = 30-46 L/kg). As it is known that the interactions of humic substances with actinides depend on various experimental parameters, the effect of HA on Np(V) sorption on 15 g/L OPA was also investigated as a function of pH (6-10) and initial Np concentration (8 {mu}M and 7 pM). A saturated calcite solution was used as a background electrolyte in this case to prevent any dissolution of calcite contained in OPA at low pH. The results showed that the presence of M42 HA increases Np(V) sorption at pH < 7 while lower sorption was obtained above pH 8. Higher sorption at acidic pH can be attributed to strong sorption of HA which increases the number of sorption sites, while sorption decreases at higher pH probably due to formation of soluble ternary neptunium humate carbonate species. (orig.)

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

    Energy Technology Data Exchange (ETDEWEB)

    Conte, Pellegrino [Dipartimento di Scienze del Suolo, della Pianta e dell' Ambiente, Universita di Napoli Federico II, Via Universita 100, 80055 Portici (Italy) and INCA Research Unit Napoli 2, Naples (Italy)]. E-mail: pellegrino.conte@unina.it; Agretto, Anna [Dipartimento di Scienze del Suolo, della Pianta e dell' Ambiente, Universita di Napoli Federico II, Via Universita 100, 80055 Portici (Italy); INCA Research Unit Napoli 2, Naples (Italy); Spaccini, Riccardo [Dipartimento di Scienze del Suolo, della Pianta e dell' Ambiente, Universita di Napoli Federico II, Via Universita 100, 80055 Portici (Italy); INCA Research Unit Napoli 2, Naples (Italy); Piccolo, Alessandro [Dipartimento di Scienze del Suolo, della Pianta e dell' Ambiente, Universita di Napoli Federico II, Via Universita 100, 80055 Portici (Italy); INCA Research Unit Napoli 2, Naples (Italy)

    2005-06-15

    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.

  6. Allelopathic effect of phenolic acids from humic solutions on two spruce mycorrhizal fungi:Cenococcum graniforme andLaccaria laccata.

    Science.gov (United States)

    Pellissier, F

    1993-10-01

    The aim of this investigation was to determine the impact ofp-hydroxyacetophenone,p-hydroxybenzoic acid, catechol, and protocatechuic acid on respiration of two spruce mycorrhizal fungi:Laccaria laccata andCenococcum graniforme. These phenols are produced byVaccinium myrtillus,Athyrium filixfemina, andPicea abies, predominant species of spruce forests in the Alps, and they are also present in humic solutions at 10(-10) M or 10(-5) M. Respiration of the two fungi was inhibited by the four phenolic acids, even at concentrations ranging from 10(-5) M to 10(-7) M. These data show phenolic acids from humic solutions have biological activity at extremely low concentrations, suggesting a contribution ofV. myrtillus, A. filixfemina, andP. abies to allelopathic inhibition of mycorrhizal fungi.

  7. 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. 

  8. 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.

  9. The effect of humic acids and their complexes with iron on the functional status of plants grown under iron deficiency

    Science.gov (United States)

    Abros'kin, D. P.; Fuentes, M.; Garcia-Mina, J. M.; Klyain, O. I.; Senik, S. V.; Volkov, D. S.; Perminova, I. V.; Kulikova, N. A.

    2016-10-01

    The effect of humic acids (HAs) and their iron complexes (Fe-HAs) on the input of the main mineral elements into wheat seedlings, as well as on the efficiency of photosynthesis and the lipid profile of plants, under iron deficiency has been studied. The input of iron from Fe-HA complexes and its predominant accumulation in roots are demonstrated. It is found that HAs increase the efficiency of photosynthesis due to enhanced electron transport in photosystem II. It is shown that the application of HAs and Fe-HAs is accompanied by an enhanced input of Zn into plants, which could increase the antioxidant status of plants under iron deficiency conditions. In addition, a pronounced increase in the content of lipids in plants is revealed, which is indicative of the effect of HAs on plant metabolism. The obtained results suggest that the positive effect of Fe-HAs and HAs on plants under iron deficiency conditions is due to a combination of factors, among which the effect of HAs on the antioxidant status of plants and the plant lipid metabolism predominates.

  10. Hexavalent chromium removal by titanium dioxide photocatalytic reduction and the effect of phenol and humic acid on its removal efficiency

    Directory of Open Access Journals (Sweden)

    Mohammad Malakootian

    2015-01-01

    Full Text Available Aims: The aim of this study is Cr (VI removal by titanium dioxide (TiO2 photocatalytic reduction and the effect of phenol and humic acid (HA on its removal efficiency are investigated. Materials and Methods: The experiments were performed on both simulated synthetic wastewater and real wastewater. Various parameters such as pH, contact time, Cr (VI and TiO 2 concentrations, and a constant concentration of phenol and HA were considered to perform the experiments. Results: The removal value of Cr (VI alone is 81% and in combination with HA and phenol is 89.7% and 96.2%, respectively. Cr (VI removal efficiency was enhanced by decreasing pH and contact time. With increasing TiO 2 dosage, the removal of Cr (VI increased, up to 0.5 g/L and then decreased at 1 g/L. Cr (VI removal efficiency decreases with the increase of Cr (VI initial concentration. Removal efficiency, in 10 mg/L initial concentration of phenol and HA, was enhanced as contact time increased. Equilibrium data and adsorption process kinetics obey Langmuir isotherm model and pseudo second-order kinetic model, respectively. Conclusions: Heavy metal ions and organic pollutants are often present in real wastewater. This research suggests that the photocatalytic reaction TiO 2 could be applied to more effectively treat wastewaters containing both Cr (VI and organic compounds.

  11. Influence of shear force on floc properties and residual aluminum in humic acid treatment by nano-Al{sub 13}

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Weiying, E-mail: stu_xuwy@ujn.edu.cn [School of Resources and Environmental Sciences, University of Jinan, Ji’nan 250022, Shandong (China); Gao, Baoyu [Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Ji’nan 250100, Shandong (China); Du, Bin; Xu, Zhenghe; Zhang, Yongfang; Wei, Dong [School of Resources and Environmental Sciences, University of Jinan, Ji’nan 250022, Shandong (China)

    2014-04-01

    Graphical abstract: Effect of shear forces on total residual Al and dissolved residual Al in humic acid coagulations by PACl and Al{sub 13} at dosages of 5.5 mg/L. Fig. a Variations of total residual Al concentrations with shear force. Fig. b Variations of dissolved residual Al concentrations with shear force. - Highlights: • Increased shear reduced floc size, strength and re-growth but improved floc D{sub f}. • HA-Al{sub 13} flocs were smaller but showed higher S{sub f}, R{sub f} and D{sub f} than HA-PACl flocs. • Higher shear resulted in higher residual Al in finished water. • Residual Al increased less with enhanced shear rate for Al{sub 13} than that for PACl. • Higher S{sub f} and R{sub f} mitigated residual Al increment but D{sub f} had little effect on it. - Abstract: The impacts of various shear forces on floc sizes and structures in humic acid coagulations by polyaluminum chloride (PACl) and nano-Al{sub 13} were comparatively studied in this paper. The dynamic floc size was monitored by use of a laser diffraction particle sizing device. The floc structure was evaluated in terms of fractal dimension, analyzed by small-angle laser light scattering (SALLS). The effect of increased shear rate on residual Al of the coagulation effluents was then analyzed on the basis of different floc characteristics generated under various shear conditions. The results showed that floc size decreased with the increasing shear rate for both Al{sub 13} and PACl. Besides, floc strength and re-formation ability were also weakened by the enhanced shear force. Al{sub 13} resulted in small, strong and better recoverable flocs than PACl and moreover, in the shear range of 100–300 revolution per minute (rpm) (G = 40.7–178.3 s{sup −1}), the characteristics of HA-Al{sub 13} flocs displayed smaller scale changes than those of HA-PACl flocs. The results of residual Al measurements proved that with shear increased, the residual Al increased continuously but Al{sub 13

  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. Influence of humic acid on plutonium sorption to gibbsite. Determination of Pu-humic acid complexation constants and ternary sorption studies

    Energy Technology Data Exchange (ETDEWEB)

    Zimmerman, Trevor; Powell, Brian A. [Clemson Univ., Anderson, SC (United States). Environmental Engineering and Earth Sciences; Zavarin, Mavrik [Lawrence Livermore National Laboratory, Livermore, CA (United States). Glenn T. Seaborg Institute

    2014-10-01

    In this work stability constants describing Pu(IV), Th(IV), and Np(V) binding to Leonardite humic acid (HA) were determined using a discrete pK{sub a} model. A hybrid ultra-filtration/equilibrium dialysis, ligand exchange technique was used to generate the partitioning data. Ethylenediaminetetraacetic acid (EDTA) was used as a reference ligand to allow the aqueous chemistry of the Pu(IV)-HA system to be examined over a range of pH values, while minimizing the possibility of precipitation of Pu(IV). The conditional stability constant for Pu(IV) complexation with HA determined as part of this work is logβ{sub 112} = 6.76 ± 0.14 based on the equation: Pu{sup 4+} + HL3 + 2H{sub 2}O <-> Pu(OH){sub 2}L3{sup +} + 3H{sup +} where HA is represented by HL3 (a binding site on the HA with a pK{sub a} value of 7). This value is three orders of magnitude higher than the Th(IV)-HA constant and between six and eight orders of magnitude higher than the Np(V)-HA complex. The magnitude of the stability constants and the general trend of increasing complexation strength with increasing pH is consistent with previous observations. The Pu(IV)-HA stability constants were used to model sorption of Pu(IV) to gibbsite in the presence of HA. Assuming only aqueous Pu-HA complexes and AlOH-Pu surface complexes, the model was unable to predict the observed data which exhibited greater sorption at pH 4 relative to pH 6; a phenomenon which does not occur in the absence of HA. Therefore, this study demonstrates that ternary Pu-HA-gibbsite complexes may form under low pH conditions and exhibit greater sorption than that observed in the absence of HA. Although the presence of HA may increase the solubility/aqueous concentrations of Pu in the absence of a solid phase, formation of ternary complexes may indeed retard the subsurface migration of Pu. The corollary to this finding is that increased mobility may occur if the ternary surface complex forms on a mobile colloid rather than part of the

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

    NARCIS (Netherlands)

    Azman, S.; Khadem, A.F.; Zeeman, G.; Van Lier, 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

  15. 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.

  16. 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.

  17. A stepwise stoichiometric representation to confirm the dependence of pesticide/humic acid interactions on salt concentration and to test the performance of a silica bonded humic acid column.

    Science.gov (United States)

    André, C; Thomassin, M; Berthelot, A; Guillaume, Y C

    2006-02-01

    In a previous paper (André et al., in press), a novel chromatographic column was developed in our laboratory for studying the binding of pesticides with humic acid (HA), the main organic component in soil. It was demonstrated that this column supported a low fraction of organic modifier in the aqueous mobile phase (equation for the partition of the added salt between the pesticide molecule, the HA, and the pesticide/HA complex. Based on this novel equation, the dependence of the pesticide/humic acid association on the salt concentration can be formulated via a relation similar to the one of Tanford. In addition, for the first time, the calculation of the affinity energy distribution for different values of the salt concentration in the mobile phase confirmed the existence of several types of binding sites on the HA macromolecule.

  18. The coagulation characteristics of humic acid by using acid-soluble chitosan, water-soluble chitosan, and chitosan coagulant mixtures.

    Science.gov (United States)

    Chen, Chih-Yu; Wu, Chung-Yu; Chung, Ying-Chien

    2015-01-01

    Chitosan is a potential substitute for traditional aluminium salts in water treatment systems. This study compared the characteristics of humic acid (HA) removal by using acid-soluble chitosan, water-soluble chitosan, and coagulant mixtures of chitosan with aluminium sulphate (alum) or polyaluminium chloride (PACl). In addition, we evaluated their respective coagulation efficiencies at various coagulant concentrations, pH values, turbidities, and hardness levels. Furthermore, we determined the size and settling velocity of flocs formed by these coagulants to identify the major factors affecting HA coagulation. The coagulation efficiency of acid- and water-soluble chitosan for 15 mg/l of HA was 74.4% and 87.5%, respectively. The optimal coagulation range of water-soluble chitosan (9-20 mg/l) was broader than that of acid-soluble chitosan (4-8 mg/l). Notably, acid-soluble chitosan/PACl and water-soluble chitosan/alum coagulant mixtures exhibited a higher coagulation efficiency for HA than for PACl or alum alone. Furthermore, these coagulant mixtures yielded an acceptable floc settling velocity and savings in both installation and operational expenses. Based on these results, we confidently assert that coagulant mixtures with a 1:1 mass ratio of acid-soluble chitosan/PACl and water-soluble chitosan/alum provide a substantially more cost-effective alternative to using chitosan alone for removing HA from water.

  19. 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.

  20. A study of metal complexation with humic and fulvic acid: the effect of temperature on association and dissociation

    Energy Technology Data Exchange (ETDEWEB)

    King, S.J.; Warwick, P. [Loughborough Univ. of Technology (United Kingdom). Dept. of Chemistry; Bryan, N. [RMC Ltd., Abingdon (United Kingdom); Manchester Univ. (United Kingdom). Dept. of Chemistry

    1999-06-01

    The main objective of the project is to determine the influence of humic substances on the migration of radionuclides. One of the first steps taken in order to deepen this understanding was to investigate the complexation of Eu{sup 3+} and UO{sub 2}{sup 2+} with humic substances (Task 2). There is concern that after disposal in underground repositories radionuclides may eventually come into contact with groundwaters containing humic substances at elevated temperatures. Investigations have therefore been undertaken to determine the temperature dependence of the stability constants for europium and uranium binding to humic and fulvic acid by a series of batch experiments. The rate at which these complexes dissociate may be a significant factor in understanding the radionuclide transportation in the environment and has been investigated over a range of environmental parameters. The derived binding strengths, enthalpies and entropies of reaction and dissociation rate constants have been used for the mechanistic modelling of metal-humate interactions by Bryan et al in this volume. (orig.)

  1. 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.

  2. Binding characteristics of Cu2+ to natural humic acid fractions sequentially extracted from the lake sediments.

    Science.gov (United States)

    He, En; Lü, Changwei; He, Jiang; Zhao, Boyi; Wang, Jinghua; Zhang, Ruiqing; Ding, Tao

    2016-11-01

    Humic acids (HAs) determine the distribution, toxicity, bioavailability, and ultimate fate of heavy metals in the environment. In this work, ten HA fractions (F1-F10) were used as adsorbent, which were sequentially extracted from natural sediments of Lake Wuliangsuhai, to investigate the binding characteristics of Cu2+ to HA. On the basis of the characterization results, differences were found between the ten extracted HA fractions responding to their elemental compositions and acidic functional groups. The characterization results reveal that the responses of ten extracted HA fractions to their elemental compositions and acidic functional groups were different. The O/C and (O + N)/C ratio of F1-F8 approximately ranged from 0.66 to 0.53 and from 0.72 to 0.61, respectively; the measured results showed that the contents of phenolic groups and carboxyl groups decreased from 4.46 to 2.60 mmol/g and 1.60 to 0.58 mmol/g, respectively. The binding characteristics of Cu2+ to the ten HA fractions were well modeled by the bi-Langmuir model; the binding behavior of Cu2+ to all the ten HA fractions were strongly impacted by pH and ionic strength. The FTIR and SEM-EDX image of HA fractions (pre- and post-adsorption) revealed that carboxyl and phenolic groups were responsible for the Cu2+ sorption on the ten sequentially extracted HA fractions process, which is the same with the analysis of the ligand binding and bi-Langmuir models Accordingly, the adsorption capacity of the former HA fractions on Cu2+ were higher than the latter ones, which may be attributed to the difference of carboxyl and phenolic group contents between the former and latter extracted HA fractions. Additionally, the functional groups with N and S should not be neglected. This work is hopeful to understand the environmental effect of humic substances, environmental geochemical behavior, and bioavailability of heavy metals in lakes.

  3. 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.

  4. Experimental study of humic acid degradation and theoretical modelling of catalytic ozonation.

    Science.gov (United States)

    Turkay, Ozge; Inan, Hatice; Dimoglo, Anatoli

    2015-01-01

    The efficiency of TiO2 as a catalyst in the ozonation of humic acid (HA) was evaluated in a comprehensive manner. Ozonation, catalytic ozonation and adsorption experiments were conducted using both synthetic HA solution and natural water. HA degradation was evaluated in terms of DOC, VIS400 and UV254. It was shown that the addition of catalyst positively affects the mechanism of ozonation. An increase in HA degradation was observed for all these parameters. The impact of catalyst dose and initial pH value of HA on the efficacy of catalytic ozonation was investigated. The highest removal efficiencies were achieved with the dose of 1 g l(-1) of TiO2 (Degussa P-25) and in the acidic pH region. The catalytic ozonation process was efficient also on natural water component although not at the same level as it was on synthetic water. The adsorptive feature of P-25 was considered to have a clear evidence of the catalytic ozonation mechanism. The mechanism of catalysis on the surface of metal oxides was elucidated with the help of quantum-chemical calculations. In the framework of Density Function Theory (DFT), the O3 decomposition was calculated in the catalytic and non-catalytic processes. Donor-acceptor properties of the frontier (highest occupied and lowest unoccupied molecular orbitals, HOMO/LUMO) orbitals are discussed. Electron density distribution and reaction mechanism of superoxide particles formation, which participate in the process of HA ozonation are analyzed.

  5. Modification of ultrafiltration membrane with nanoscale zerovalent iron layers for humic acid fouling reduction.

    Science.gov (United States)

    Ma, Baiwen; Yu, Wenzheng; Jefferson, William A; Liu, Huijuan; Qu, Jiuhui

    2015-03-15

    Nanoscale zerovalent iron (NZVI) was layered onto ultrafiltration (UF) membrane surface and tested for antifouling properties using humic acid (HA). Scanning electron microscopy showed that a relatively homogeneous layer was formed across the membrane surface by NZVI particles. Strong adhesion was observed between NZVI and UF membrane used. HA was significantly removed and membrane flux was increased in the presence of NZVI layer. Increased loadings of NZVI onto the membrane surface increased resistance to fouling while slightly reducing the clean water permeability of the membrane. However, the pore size of the layer formed by pristine NZVI was large, resulting in more chances of HA molecules getting to the membrane surface even blocking the membrane pores at the beginning. Membrane loaded with NZVI layer performed much better under acidic conditions. During NZVI synthesis, specific surface area of NZVI particle increased with increasing the ratio of ethanol (Vethanol/Vsolution), which also gradually decreased the average pore size of NZVI layer. As a result, the corresponding membrane flux steadily increased. Additionally, the results for permeate samples under different conditions showed that large molecular weight (MW, >30 kDa) and medium MW HA molecules (3-30 kDa) were removed much faster than those of small MW HA molecules (<3 kDa). Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Relative importance of humic and fulvic acid on ROS generation, dissolution, and toxicity of sulfide nanoparticles.

    Science.gov (United States)

    Shang, Enxiang; Li, Yang; Niu, Junfeng; Zhou, Yijing; Wang, Tianyu; Crittenden, John Charles

    2017-11-01

    In this study, the effect of natural organic matter (NOM) composition (humic acid (HA) or fulvic acid (FA)) on dissolution, reactive oxygen species (ROS) generation, and toxicity of sulfide nanoparticles (NPs) was investigated under UV irradiation. NOM acted as a UV filter or antioxidant, decreasing ROS (O2-, OH, and 1O2) generation by WS2 and MoS2 NPs. The higher light-absorbing fractions of HA in NP/HA mixtures and the faster reaction rate of HA with ROS resulted in higher inhibition effect of HA than FA on O2- and OH generation by WS2 and MoS2 NPs. Both HA and FA completely inhibited 1O2 generation by WS2 and MoS2 NPs. NOM could transfer electrons to CdS and promote its O2- generation. No measurable amount of OH was generated by CdS with or without NOM. FA decreased 1O2 generation by CdS more significantly than HA due to the higher reaction rate between FA and 1O2. HA showed a higher inhibition effect on the dissolution rate of CdS and WS2 NPs than FA. Both HA and FA played minor roles in the toxicity of CdS toward Escherichia coli but decreased the toxicity of MoS2 and WS2 due to the reduced ROS generation and/or dissolution concentrations. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. 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.

  8. Dispersion and stability of bare hematite nanoparticles: effect of dispersion tools, nanoparticle concentration, humic acid and ionic strength

    Science.gov (United States)

    Dickson, Dionne; Liu, Guangliang; Li, Chenzhong; Tachiev, Georgio; Cai, Yong

    2012-01-01

    The aggregation and sedimentation of iron oxide nanoparticles (IONPs) can significantly affect the mobility and reactivity of IONPs and subsequently influence the interaction between IONPs and environmental contaminants. Dispersing bare IONPs into a stable suspension within nanoscale range is an important step for studying the interaction of IONPs with contaminants (e.g., toxic metals). In this study, different techniques to disperse bare IONPs (vortex, bath sonication and probe ultrasonication) and the effects of important environmental factors such as dissolved organic matter and ionic strength on the stability of IONPs dispersions were investigated. Vortex minimally dispersed IONPs with hydrodynamic diameter outside the “nanosize range” (698–2400nm). Similar to vortex, bath sonication could not disperse IONPs efficiently. Probe ultrasonication was more effective at dispersing IONPs (50% or more) with hydrodynamic diameters ranging from 120–140 nm with minimal changes in size and sedimentation of IONPs for a prolonged period of time. Over the course of 168 hours, considerable amounts of IONPs remained dispersed in the presence and absence of low ionic strength (0.1 mM of NaCl) and 100 mg/L of humic acid (HA). These results indicate that IONPs can be broken down efficiently into “nanosize range” by probe ultrasonication and a degree of stability can be achieved without the use of synthetic modifiers to enhance colloidal stability. This dispersion tool could be used to develop a laboratory method to study the adsorption mechanism between dispersed bare IONPs and toxic contaminants. PMID:22289174

  9. Effect of humic acid on the sorption of perfluorooctane sulfonate (PFOS) and perfluorobutane sulfonate (PFBS) on boehmite.

    Science.gov (United States)

    Wang, Fei; Shih, Kaimin; Leckie, James O

    2015-01-01

    The sorption of PFOS and PFBS on boehmite was significantly retarded by the competitive sorption of humic acid (HA), implying that PFOS and PFBS are likely more mobile in water and groundwater systems enriched with HA. The sorption behavior of PFOS and PFBS on the HA-modified boehmite surface were also found to differ due to their different chain lengths. For a partially HA-modified boehmite surface, the isotherm study showed that PFOS had a much higher maximum sorption capacity than PFBS and that PFOS might possess additional surface interactions besides electrostatic interaction. For a HA-saturated boehmite, a linear sorption isotherm was found for PFOS while nearly no PFBS sorption was observed. This indicates that sorption behavior between PFOS and the sorbed HA on boehmite was dominated by hydrophobic interactions, instead of electrostatic interaction. In addition, a conceptual model combining hydrophobic and electrostatic interaction was established to explain the sorption behavior of PFOS and PFBS on HA-modified boehmite. Finally, the results revealed that the sorption of PFOS and PFBS on HA-modified boehmite is pH-dependent. The neutralization of negative sites on HA-modified boehmite reduced the electrostatic repulsion and enhanced the partitioning of PFBS on the sorbed HA. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Humic acid inhibits HBV-induced autophagosome formation and induces apoptosis in HBV-transfected Hep G2 cells.

    Science.gov (United States)

    Pant, Kishor; Yadav, Ajay K; Gupta, Parul; Rathore, Abhishek Singh; Nayak, Baibaswata; Venugopal, Senthil K

    2016-10-06

    Hepatitis B Virus (HBV) utilizes several mechanisms to survive in the host cells and one of the main pathways being autophagosome formation. Humic acid (HA), one of the major components of Mineral pitch, is an Ayurvedic medicinal food, commonly used by the people of the Himalayan regions of Nepal and India for various body ailments. We hypothesized that HA could induce cell death and inhibit HBV-induced autophagy in hepatic cells. Incubation of Hep G2.2.1.5 cells (HepG2 cells stably expressing HBV) with HA (100 μM) inhibited both cell proliferation and autophagosome formation significantly, while apoptosis induction was enhanced. Western blot results showed that HA incubation resulted in decreased levels of beclin-1, SIRT-1 and c-myc, while caspase-3 and β-catenin expression were up-regulated. Western blot results showed that HA significantly inhibited the expression of HBx (3-fold with 50 μM and 5-fold with 100 μM) compared to control cells. When HA was incubated with HBx-transfected Hep G2 cells, HBx-induced autophagosome formation and beclin-1 levels were decreased. These data showed that HA induced apoptosis and inhibited HBV-induced autophagosome formation and proliferation in hepatoma cells.

  11. Eu(III) uptake on rectorite in the presence of humic acid: a macroscopic and spectroscopic study.

    Science.gov (United States)

    Chen, Changlun; Yang, Xin; Wei, Juan; Tan, Xiaoli; Wang, Xiangke

    2013-03-01

    This work contributed to the comprehension of humic acid (HA) effect on Eu(III) uptake to Na-rectorite by batch sorption experiments, model fitting, scanning electron microscopy, powder X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and extended X-ray absorption fine structure (EXAFS) spectroscopy. At low pH, the presence of HA enhanced Eu(III) sorption on Na-rectorite, while reduced Eu(III) sorption at high pH. The experimental data of Eu(III) sorption in the absence and presence of HA were simulated by the diffuse-layer model well with the aid of FITEQL 3.2 software. The basal spacing of rectorite became large after Eu(III) and HA sorption on Na-rectorite. Some of Eu(III) ions and HA might be intercalated into the interlayer space of Na-rectorite. EXAFS analysis showed that the R(Eu-O) (the bond distance of Eu and O in the first shell of Eu) and N values (coordination number) of Eu(III)-HA-rectorite system were smaller than those of Eu(III)-rectorite system. Copyright © 2012 Elsevier Inc. All rights reserved.

  12. Humic acid acts as a natural antidote of graphene by regulating nanomaterial translocation and metabolic fluxes in vivo.

    Science.gov (United States)

    Hu, Xiangang; Mu, Li; Kang, Jia; Lu, Kaicheng; Zhou, Ruiren; Zhou, Qixing

    2014-06-17

    Graphene-related research has intensified rapidly in a wide range of disciplines, but few studies have examined ecosystem risks, particularly phytotoxicity. This study revealed that graphene significantly inhibits the number of wheat roots and the biosynthesis of chlorophyll, and altered the morphology of shoots. Humic acid (HA), a ubiquitous form of natural organic matter, significantly (P nanomaterial risks and can be used to control nanomaterial contamination.

  13. Evaluation of Performance Catalytic Ozonation Process with Activated Carbon in the Removal of Humic Acids from Aqueous Solutions

    Directory of Open Access Journals (Sweden)

    Gh. Asgari

    2011-01-01

    Full Text Available Introduction & Objective: In recent years, the use of alternative disinfectants and the control of natural organic matters are two approaches that are typically applied in water treatment utilities to reduce the formation of chlorinated disinfection by-products. Catalytic ozonation is a new technology used to promote the efficiency of ozonation. The goal of this study was to survey the feasibility application of activated carbon as a catalyst in ozonation process for removal of humic acids from aqueous solution. Materials & Methods: This experimental study has been done in laboratory of water and wastewater chemistry, Tarbiat Modarres University. The solid structure and chemical composition of activated carbon were analyzed by X-ray fluorescence (XRF. Ozonation and catalytic ozonation experiments were performed in a semi-batch reactor and the mass of ozone produced was measured by iodometric titration methods. Concentration changes of humic acid in samples with a concentration of 15 mg/l were determined by using spectrophotometer at an absorbance wavelength of 254 nm. To evaluate the performance of catalytic ozonation in humic acid removal, total organic carbon and trihalomethane formation potential were evaluated and the results were analyzed by Excel software. Results: Catalytic ozone results showed that using activated carbon as a catalyst increased humic acid decomposition up to 11 times and removal efficiency increased with increasing pH (4-12 and catalyst dosage (0.25-1.5 g/250cc. The experimental results showed that catalytic ozonation was most effective in less time (10 min with considerable efficiency (95% compared to the sole ozonation process (SOP. Conclusion: The results indicated that the catalytic ozonation process, compared to SOP, was less affected by radical scavenger, and total organic carbon, and trihalomethane formation potential removal achieved were 30% and 83%, respectively. (Sci J Hamadan Univ Med Sci 2011;17(4:25-33

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

    OpenAIRE

    Ievinsh Gederts; Vikmane Māra; Ķirse Agnese; Karlsons Andis

    2017-01-01

    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 s...

  15. Effect of Foliar Applications of Humic Acid, Iron and Zinc on some Characteristics of Negro (Guizotia abyssinica L.

    Directory of Open Access Journals (Sweden)

    Ali Tadayyon

    2016-06-01

    Full Text Available One of the most important needs in farm planning is the evaluation of different systems of plant nutrition. By supplying the correct way of plant nutrition you can preserve the environment and increase efficiency of agricultural inputs. In order to investigate the effect of foliar application of organic fertilizers and micronutrients on some characteristics of neger, a field experiment was conducted in a complete randomized block design with three replications at Agricultural Research Station of Shahrekord University in 2013-2014. Treatments consisted of control, three levels of humic acid (1, 3, and 6 liters/ha of humic acid, iron (4 per thousand, and zinc (4 per thousand. In this experiment traits like plant height, stem diameter, stem branch number, biological yield, seed yield, harvest index, and percent and oil yield were evaluated. The results showed that foliar application of these materials resulted in significant increase in the traits under study. Oil yield increased by 63 and 53 percent with the use of 6 liters humic acid and zinc respectively, as compared to the use of 1 liter per hectare. This may be the outcome of increased in oil yield and protein content. Meanwhile, the highest percentage of protein observed for tratment of 6 liters per hectare. The highest response of traits firstly obtained by use of 6 liters per hectare humic acid and then from spraying plants with the zinc which shows its limited absorption and/or probably the lack of this element in the soil where the experiment was conducted.

  16. 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.

  17. 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.

  18. Effect of phosphate on removal of humic substances by aluminum sulfate coagulant.

    Science.gov (United States)

    Cheng, Wen Po; Chi, Fung Hwa; Yu, Ruey Fang

    2004-04-01

    The presence of humic acid may change the way phosphate is absorbed or stabilized by soil and how it influences the growth of plants. The binding of phosphate with the humic substance requires bridging between phosphate ions and humic acid by metal ions, such as aluminum or iron ions. The bridging reaction can take place in peat and allophane soil under acidic conditions, altering the effectiveness of the phosphate in soil. Whether ternary phosphate-metal-HA complexes are actually formed has not yet been verified. This study considers variation in fluorescence intensity (FI) under various coagulation conditions to assess the mechanism by which humic acids and phosphate react with aluminum ions. A bond between the functional group of the humic acid and the electron-releasing group of the phosphate will enhance the florescent intensity of humic acids. Consequently the removal efficiency of humic acid, measured by florescence, declines as the phosphate concentration increases at low pH. This observation suggests that at low coagulation pH, the positively charged aluminum species can be used to bridge between the phosphate ion and the humic acid molecules.

  19. Reduction of Ammonia Volatilization through Mixing Urea with Humic and Fulvic Acids isolated from Palm Oil Mill Effluent Sludge

    OpenAIRE

    Shamsuddin Rosliza; Osumanu H. Ahmed; Nik M.A. Majid; Mohamadu B. Jalloh

    2009-01-01

    Problem statement: Ammonia volatilization from surface-applied urea may be substantial but it is possible to control it by mixing urea with acidic substances such as Humic Acids (HA) and Fulvic Acids (FA). The objective of this study was to compare the effects of urea-HA, urea-FA, urea-acidified (HA+FA) mixtures on ammonia loss, soil pH, soil exchangeable ammonium and available nitrate accumulation compared to urea alone. Approach: The effects of urea amended with or without HA and FA were ev...

  20. 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.

  1. 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.

  2. [Analysis on the impact of composting with different proportions of corn stalks and pig manure on humic acid fractions and IR spectral feature].

    Science.gov (United States)

    Sun, Xiang-Ping; Li, Guo-Xue; Xiao, Ai-Ping; Shi, Hong; Wang, Yi-Ming; Li, Yang-Yang

    2014-09-01

    Using pig manure and corn straw as raw materials for high-temperature composting, setting three different treat- ments: C/N 15, C/N 25, and C/N 35. Composting period is 120 days, which contains 30 days for ventilation cycle by forced continuous ventilation. Sampled on 0, 22, 30, 60, 90, 120th days, they were analyzed by elemental analysis and IR spectroscopy to study effect of different lignin content on compost humic acid (HA) composition and molecular structure. The results showed that the change in composting humic acid C focused on the first 30 days, while after composting, the O/C of compost HA increased, H/C decreased, and N content increased. Low C/N (15) and higher C/N ratio (35) had higher degree of oxidation than the C/N 25 in compost HA. FTIR indicated that the infrared spectrum shapes with different lignin content treatment are similar during the composting process, but the peak intensity is obviously different. Research results proved that the composting stage is more conducive to enhanced aromatic in compost HA. After composting, C/N 15 had less polysaccharide and fat ingredients and more aromatic structural components in compost HA, compared with C/N 25 and 35. In addition, compost HA of C/N 15 had higher degree of humification and its structure was more stable.

  3. Effect of soil tillage intensity on the composition, physical and chemical properties of the second fraction of humic acids extracted from the typical black soil

    Directory of Open Access Journals (Sweden)

    M. A. Popirny

    2016-10-01

    Full Text Available The purpose of this work lies in studying the composition, physical and chemical properties of the second fraction of the humic acid (HA2 extracted from the typical black soil, depending on the intensity of the soil tillage. Physical and chemical properties of HA2 have been studied by using ultraviolet (UV spectroscopy, infrared (IR spectroscopy and electron spin resonance spectroscopy (ESR. It has been demonstrated that increase of the tillage intensity of the typical black soil leads to decrease in the total carbon content and the HA2 content due to displacement of balance between the conjugated processes of humus synthesis and decay towards destruction. UV spectroscopy indicates intense absorption of humic acids in the near UV region, that corresponds to the donor-acceptor mechanisms π-π* electrons of double bonds. Maximum absorption has been observed for the HA2 isolated from the black soil tilled by plowing. Moreover, the highest content of oxygen-containing functional groups and low quantity of aliphatic structures has been observed in the same sample. It has been shown that the nature of paramagnetic centers of the HA2 represented by chelate paramagnetic Fe3+-complex formed by rearrangement π-electron system of double bonds, depending on the tillage intensity of the typical black soil. It has been found that plowing of the typical black soil enhances the number of paramagnetic centers in HA2.

  4. Determination of total antioxidant capacity of humic acids using CUPRAC, Folin-Ciocalteu, noble metal nanoparticle- and solid-liquid extraction-based methods.

    Science.gov (United States)

    Karadirek, Şeyda; Kanmaz, Nergis; Balta, Zeynep; Demirçivi, Pelin; Üzer, Ayşem; Hızal, Jülide; Apak, Reşat

    2016-06-01

    Total antioxidant capacity (TAC) of humic acid (HA) samples was determined using CUPRAC (CUPric Reducing Antioxidant Capacity), FC (Folin-Ciocalteu), QUENCHER-CUPRAC, QUENCHER-FC, Ag-NP (Silver nanoparticle)‒ and Au-NP (Gold nanoparticle)‒based methods. Conventional FC and modified FC (MFC) methods were applied to solid samples. Because of decreased solubility of Folin-Ciocalteu's phenol reagent in organic solvents, solvent effect on TAC measurement was investigated using QUENCHER-CUPRAC assay by using ethanol:distilled water and dimethyl sulfoxide:distilled water with varying ratios. To see the combined effect of solubilization (leaching) and TAC measurement of humic acids simultaneously, QUENCHER experiments were performed at 25°C and 50°C; QUENCHER-CUPRAC and QUENCHER-FC methods agreed well and had similar precision in F-statistics. Although the Gibbs free energy change (ΔG°) of the oxidation of HA dihydroxy phenols with the test reagents were negative, the ΔG° was positive only for the reaction of CUPRAC reagent with isolated monohydric phenols, showing CUPRAC selectivity toward polyphenolic antioxidants. This is the first work on the antioxidant capacity measurement of HA having a sparingly soluble matrix where enhanced solubilization of bound phenolics is achieved with coupled oxidation by TAC reagents. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. 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.

  6. 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.

  7. Effective removal of humic acid using xanthan gum incorporated polyethersulfone membranes.

    Science.gov (United States)

    Sathish Kumar, R; Arthanareeswaran, G; Paul, Diby; Kweon, Ji Hyang

    2015-11-01

    In this study, xanthan gum (XA) was used as a hydrophilic biopolymer additive for the modification of polyethersulfone (PES) membrane to removal of humic acid (HA). The membranes are prepared using phase inversion technique and the concentration of XA was varied from 0.5 to 1.5wt%. The prepared membranes are characterized as a function of hydrophilicity, equilibrium water content (EWC), porosity studies and functional group analysis. Membrane surface and cross-sectional morphology was studied using scanning electron microscope. The lower contact angle value 64.2° was exhibited, when 1.5wt% of XA incorporated in PES membrane and this ensures that increase of hydrophilicity in pristine PES membrane. Further, higher water permeability (PWP) of 68.9(-9)m/skPa was observed for 1.5wt% of XA/PES membrane. The effect of pH on HA removal was studied for neat PES and XA/PES membranes. The rejection performance of XA incorporated in PES membranes were compared with commercial available PES membrane. Copyright © 2015 Elsevier Inc. All rights reserved.

  8. 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

  9. 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.

  10. 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.

  11. Humic acid transport in saturated porous media: influence of flow velocity and influent concentration.

    Science.gov (United States)

    Wei, Xiaorong; Shao, Mingan; Du, Lina; Horton, Robert

    2014-12-01

    Understanding the transport of humic acids (HAs) in porous media can provide important and practical evidence needed for accurate prediction of organic/inorganic contaminant transport in different environmental media and interfaces. A series of column transport experiments was conducted to evaluate the transport of HA in different porous media at different flow velocities and influent HA concentrations. Low flow velocity and influent concentration were found to favor the adsorption and deposition of HA onto sand grains packed into columns and to give higher equilibrium distribution coefficients and deposition rate coefficients, which resulted in an increased fraction of HA being retained in columns. Consequently, retardation factors were increased and the transport of HA through the columns was delayed. These results suggest that the transport of HA in porous media is primarily controlled by the attachment of HA to the solid matrix. Accordingly, this attachment should be considered in studies of HA behavior in porous media. Copyright © 2014. Published by Elsevier B.V.

  12. Dynamics and thermodynamics of toxic metals adsorption onto soil-extracted humic acid.

    Science.gov (United States)

    Shaker, Medhat A; albishri, Hassan M

    2014-09-01

    Humic acids, HA represent a large portion of natural organic matter in soils, sediments and waters. They are environmentally important materials due to their extensive ubiquity and strong complexation ability, which can influence heavy metal removal and transportation in waters. The thermodynamics and kinetics of the adsorption of Cd(II) and Cr(VI) onto solid soil-derived HA have been investigated at optimum conditions of pH (5.5±0.1), metal concentration (10-100mmolL(-1)) and different temperatures (293-323K). The suitability of adsorption models such as Freundlich and Langmuir to equilibrium data was investigated. The adsorption was well described by Langmuir isotherm model in multi-detectable steps. Adsorption sites, i (i=A, B, C) with different capacities, νi are characterized. The stoichiometric site capacity is independent of temperature and equilibrium constant, Ki. Adsorption sites A and B are selectively occupied by Cr(VI) cations while sites A and C are selectively occupied by Cd(II) cations. The thermodynamic parameters of adsorption systems are correlated for each adsorption step. The adsorption is endothermic, spontaneous and favorable. Different kinetic models are applied and the adsorption of these heavy metals onto HA follows pseudo-second-order kinetics and equilibrium is achieved within 24h. The adsorption reaction is controlled by diffusion processes and the type of the adsorption is physical. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. The influence of humic acids on desalination process with the use of electrodialysis

    Directory of Open Access Journals (Sweden)

    Grzegorzek Martyna

    2017-01-01

    Full Text Available With every year amount of drinking water in the world becomes smaller. One of the possible way to solve the problem with water scarcity is desalination. The aim of this paper is to evaluate the use of electrodialysis for salt removal in the presence of organic matter. During the tests installation PCCell BED-1-System was applied. Desalination was conducted with the use of standard ion-exchange membranes. The treated solutions contained 0.5 and 1 g NaCl/dm3. The solution poured into a diluate chamber was also supplemented with humic acids (concentration amounted to 5, 10 and 15 mg/dm3. The current intensity was equal to 0.11 A (current density equal to 1.72 mA/cm2. The process was terminated when voltage reached 24 V. During the tests conductivity, colour and voltage was monitored. Also specific electrical energy demand (EC was calculated. It has been found that electrodialysis can be used as an effective method for salt removal. In most cases conductivity was reduced by approximately 90%. The main factor which influenced EC and process duration was mineral salt content. Besides, it has been observed that organic matter had a slight impact on the process course.

  14. Vermicompost humic acids modulate the accumulation and metabolism of ROS in rice plants.

    Science.gov (United States)

    García, Andrés Calderín; Santos, Leandro Azevedo; de Souza, Luiz Gilberto Ambrósio; Tavares, Orlando Carlos Huertas; Zonta, Everaldo; Gomes, Ernane Tarcisio Martins; García-Mina, José Maria; Berbara, Ricardo Luis Louro

    2016-03-15

    This work aims to determine the reactive oxygen species (ROS) accumulation, gene expression, anti-oxidant enzyme activity, and derived effects on membrane lipid peroxidation and certain stress markers (proline and malondialdehyde-MDA) in the roots of unstressed and PEG-stressed rice plants associated with vermicompost humic acid (VCHA) application. The results show that the application of VCHA to the roots of unstressed rice plants caused a slight but significant increase in root ROS accumulation and the gene expression and activity of the major anti-oxidant enzymes (superoxide dismutase and peroxidase). This action did not have negative effects on root development, and an increase in both root growth and root proliferation occurred. However, the root proline and MDA concentrations and the root permeability results indicate the development of a type of mild stress associated with VCHA application. When VCHA was applied to PEG-stressed plants, a clear alleviation of the inhibition in root development linked to PEG-mediated osmotic stress was observed. This was associated with a reduction in root ROS production and anti-oxidant enzymatic activity caused by osmotic stress. This alleviation of stress caused by VCHA was also reflected as a reduction in the PEG-mediated concentration of MDA in the root as well as root permeability. In summary, the beneficial action of VCHA on the root development of unstressed or PEG-stressed rice plants clearly involves the modulation of ROS accumulation in roots. Copyright © 2016 Elsevier GmbH. All rights reserved.

  15. Separation of macromolecular proteins and removal of humic acid by cellulose acetate modified UF membranes.

    Science.gov (United States)

    Kanagaraj, P; Nagendran, A; Rana, D; Matsuura, T

    2016-08-01

    Surface modifying macromolecules (SMMs) were synthesized with various polyurethane pre polymers end-capped with different groups and blended into the casting solution of cellulose acetate (CA) to prepare surface modified ultra-filtration (UF) membranes for water filtration applications. The surface modification of the CA membranes was confirmed by the FTIR and static contact angle (SCA) measurements. The membranes so prepared had the typical characteristics of UF membranes as confirmed by scanning electron microscopy (SEM). Membrane properties were studied in terms of membrane compaction, percentage water content (%WC), pure water flux (PWF), membrane hydraulic resistance (Rm), molecular weight cut-off (MWCO), average pore size and porosity. The result showed that PWF, %WC, MWCO and pore size increased whereas the Rm decreased by the addition of SMMs. The significant effect of SMMs on the fouling by humic acid (HA) was also observed. It was found that the cSMM-3 membrane, in which SMM was synthesized with diethylene glycol (DEG) and hydroxyl benzene sulfonate (HBS) was blended, had the highest flux recovery ratio FRR (84.6%), as well as the lowest irreversible fouling (15.4%), confirming their improved antifouling properties. Thus, the SMM modified CA membranes had proven, to play an important role in the water treatment by UF. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Microbial reduction of Fe(III)-bearing clay minerals in the presence of humic acids

    Science.gov (United States)

    Liu, Guangfei; Qiu, Shuang; Liu, Baiqing; Pu, Yiying; Gao, Zhanming; Wang, Jing; Jin, Ruofei; Zhou, Jiti

    2017-03-01

    Both Fe(III)-bearing clay minerals and humic acids (HAs) are abundant in the soils and sediments. Previous studies have shown that bioreduction of structural Fe(III) in clay minerals could be accelerated by adding anthraquinone compound as a redox-active surrogate of HAs. However, a quinoid analogue could not reflect the adsorption and complexation properties of HA, and little is known about the effects of real HAs at environmental concentration on bioreduction of clay minerals. Here, it was shown that 10-200 mg l-1 of natural or artificially synthesized HAs could effectively stimulate the bioreduction rate and extent of Fe(III) in both iron-rich nontronite NAu-2 and iron-deficient montmorillonite SWy-2. After adsorption to NAu-2, electron-transfer activities of different HA fractions were compared. Additionally, Fe(II) complexation by HAs also contributed to improvement of clay-Fe(III) bioreduction. Spectrosopic and morphological analyses suggested that HA addition accelerated the transformation of NAu-2 to illite, silica and siderite after reductive dissolution.

  17. Column experiments to investigate transport of colloidal humic acid through porous media during managed aquifer recharge

    Science.gov (United States)

    Liu, Dan; Zhou, Jingjing; Zhang, Wenjing; Huan, Ying; Yu, Xipeng; Li, Fulin; Chen, Xuequn

    2016-09-01

    Colloids act as vectors for pollutants in groundwater, thereby creating a series of environmental problems. While managed aquifer recharge plays an important role in protecting groundwater resources and controlling land subsidence, it has a significant effect on the transport of colloids. In this study, particle size and zeta potential of colloidal humic acid (HA) have been measured to determine the effects of different hydrochemistry conditions. Column experiments were conducted to examine the effects on the transport of colloidal HA under varying conditions of pH (5, 7, 9), ionic strength (<0.0005, 0.02, 0.05 M), cation valence (Na+, Ca2+) and flow rate (0.1, 0.2, 0.4 ml/min) through collectors (glass beads) to model the properties and quality of artificial recharge water and changes in the hydrodynamic field. Breakthrough curves showed that the behavior of colloidal HA being transported varied depending on the conditions. Colloid transport was strongly influenced by hydrochemical and hydrodynamic conditions. With decreasing pH or increasing ionic strength, a decrease in the peak effluent concentration of colloidal HA and increase in deposition could be clearly seen. Comparison of different cation valence tests indicated that changes in transport and deposition were more pronounced with divalent Ca2+ than with monovalent Na+. Changes in hydrodynamic field (flow rate) also had an impact on transportation of colloidal HA. The results of this study highlight the need for further research in this area.

  18. Modelling metal accumulation using humic acid as a surrogate for plant roots.

    Science.gov (United States)

    Le, T T Yen; Swartjes, Frank; Römkens, Paul; Groenenberg, Jan E; Wang, Peng; Lofts, Stephen; Hendriks, A Jan

    2015-04-01

    Metal accumulation in roots was modelled with WHAM VII using humic acid (HA) as a surrogate for root surface. Metal accumulation was simulated as a function of computed metal binding to HA, with a correction term (E(HA)) to account for the differences in binding site density between HA and root surface. The approach was able to model metal accumulation in roots to within one order of magnitude for 95% of the data points. Total concentrations of Mn in roots of Vigna unguiculata, total concentrations of Ni, Zn, Cu and Cd in roots of Pisum sativum, as well as internalized concentrations of Cd, Ni, Pb and Zn in roots of Lolium perenne, were significantly correlated to the computed metal binding to HA. The method was less successful at modelling metal accumulation at low concentrations and in soil experiments. Measured concentrations of Cu internalized in L. perenne roots were not related to Cu binding to HA modelled and deviated from the predictions by over one order of magnitude. The results indicate that metal uptake by roots may under certain conditions be influenced by conditional physiological processes that cannot simulated by geochemical equilibrium. Processes occurring in chronic exposure of plants grown in soil to metals at low concentrations complicate the relationship between computed metal binding to HA and measured metal accumulation in roots. Copyright © 2014 Elsevier Ltd. All rights reserved.

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

    Energy Technology Data Exchange (ETDEWEB)

    Besse-Hoggan, Pascale, E-mail: Pascale.Besse@univ-bpclermont.f [Laboratoire de Synthese et Etude de Systemes a Interet Biologique, UMR-CNRS 6504, Universite Blaise Pascal, 63177 Aubiere Cedex (France); Alekseeva, Tatiana [Institute of Physical, Chemical and Biological Problems of Soil Science, Russian Academy of Sciences, Pushchino, Moscow Region 142290 (Russian Federation); Laboratoire des Materiaux Inorganiques, UMR-CNRS 6002, Universite Blaise Pascal, 63177 Aubiere Cedex (France); Sancelme, Martine; Delort, Anne-Marie [Laboratoire de Synthese et Etude de Systemes a Interet Biologique, UMR-CNRS 6504, Universite Blaise Pascal, 63177 Aubiere Cedex (France); Forano, Claude [Laboratoire des Materiaux Inorganiques, UMR-CNRS 6002, Universite Blaise Pascal, 63177 Aubiere Cedex (France)

    2009-10-15

    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. Dynamic modeling of copper bioaccumulation by Mytilus edulis in the presence of humic acid aggregates.

    Science.gov (United States)

    Sánchez-Marín, Paula; Aierbe, Eneko; Lorenzo, J Ignacio; Mubiana, Valentine K; Beiras, Ricardo; Blust, Ronny

    2016-09-01

    Copper (Cu) complexation by humic acids (HA) is expected to decrease Cu bioavailability for aquatic organisms as predicted by metal bioavailability models, such as the biotic ligand model (BLM). This has been confirmed for non-feeding organisms such as marine invertebrate embryos or microalgae, but for filter-feeding organisms such as the mussel Mytilus edulis, Cu bioaccumulation was higher in the presence of HA, suggesting that part of the Cu-HA complexes were available for uptake. This study shows the dynamic modeling of Cu accumulation kinetics in the gills and rest of the soft-body of M. edulis in the absence and presence of HA. Assuming that truly dissolved Cu is taken in the body via the gills following BLM premises, and including uptake of Cu-HA aggregates via the gut into the rest compartment, this two-compartmental model could successfully explain the observed bioaccumulation data. This modeling approach gives strong evidence to the hypothesis that Cu-HA aggregates can be ingested by mussels leading to Cu absorption in the digestive system. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Evaluation of the potentials of humic acid removal in water by gas phase surface discharge plasma.

    Science.gov (United States)

    Wang, Tiecheng; Qu, Guangzhou; Ren, Jingyu; Yan, Qiuhe; Sun, Qiuhong; Liang, Dongli; Hu, Shibin

    2016-02-01

    Degradation of humic acid (HA), a predominant type of natural organic matter in ground water and surface waters, was conducted using a gas phase surface discharge plasma system. HA standard and two surface waters (Wetland, and Weihe River) were selected as the targets. The experimental results showed that about 90.9% of standard HA was smoothly removed within 40 min's discharge plasma treatment at discharge voltage 23.0 kV, and the removal process fitted the first-order kinetic model. Roles of some active species in HA removal were studied by evaluating the effects of solution pH and OH radical scavenger; and the results presented that O3 and OH radical played significant roles in HA removal. Scanning electron microscope (SEM) and FTIR analysis showed that HA surface topography and molecular structure were changed during discharge plasma process. The mineralization of HA was analyzed by UV-Vis spectrum, dissolved organic carbon (DOC), specific UV absorbance (SUVA), UV absorption ratios, and excitation-emission matrix (EEM) fluorescence. The formation of disinfection by-products during HA sample chlorination was also identified, and CHCl3 was detected as the main disinfection by-product, but discharge plasma treatment could suppress its formation to a certain extent. In addition, approximately 82.3% and 67.9% of UV254 were removed for the Weihe River water and the Wetland water after 40 min of discharge plasma treatment. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Studying arsenite-humic acid complexation using size exclusion chromatography-inductively coupled plasma mass spectrometry.

    Science.gov (United States)

    Liu, Guangliang; Cai, Yong

    2013-11-15

    Arsenic (As) can form complexes with dissolved organic matter (DOM), which affects the fate of arsenic in waste sites and natural environments. It remains a challenge to analyze DOM-bound As, in particular by using a direct chromatographic separation method. Size exclusion chromatography (SEC) hyphenated with UV spectrophotometer and inductively coupled plasma mass spectrometry (ICP-MS) was developed to characterize the complexation of arsenite (As(III)) with DOM. This SEC-UV-ICP-MS method is able to differentiate As(III)-DOM complexes from free As species and has the advantage of direct determination of both free and DOM-bound As(III) through mild separation. The suitability of this method for studying As(III)-DOM complexation was demonstrated by its application, in combination with the Scatchard plot and nonlinear regression of ligand binding model, for characterizing As(III) complexation with humic acid (HA) in the absence or presence of natural sand. The results suggest that, consistent with polyelectrolytic nature of HA, the As(III)-HA complexation should be accounted for by multiple classes of binding sites. By loosely classifying the binding sites into strong (S1) and weak (S2) sites, the apparent stability constants (Ks) of the resulting As-DOM complexes were calculated as logK(s1) = 6.5-7.1 while logK(s2) = 4.7-5.0. Copyright © 2012 Elsevier B.V. All rights reserved.

  3. Specific adsorption of arsenic and humic acid on Pt and PtO films

    Energy Technology Data Exchange (ETDEWEB)

    Menezes, Hebert A. [Department of Chemistry, Universidade Federal de Mato Grosso do Sul, Av. Filinto Muller, 1555, Cidade Universitaria s/n, C.P. 549, Campo Grande, MS 79070-900 (Brazil); Maia, Gilberto, E-mail: gmaia@nin.ufms.b [Department of Chemistry, Universidade Federal de Mato Grosso do Sul, Av. Filinto Muller, 1555, Cidade Universitaria s/n, C.P. 549, Campo Grande, MS 79070-900 (Brazil)

    2010-07-01

    A study of specific adsorption of arsenic (As) and humic acid (HM) onto Pt and PtO films using cyclic voltammetry and cyclic massogram in 0.5-M H{sub 2}SO{sub 4} is presented, which may serve as an alternative to studies involving specific adsorption of these species on soil minerals. Adsorption of As is normally evaluated by conducting batch adsorption experiments, followed by analysis using hydride-generation atomic absorption spectrophotometry (HGAA) or inductively coupled plasma-optical emission spectrometry (ICP-OES). We found that specific adsorption of As and HM depends both on the surface and on these species present in the adsorption solution. HM does not desorb previously adsorbed As at the HM concentrations used in the present study, but it does co-adsorb with As from a 1 x 10{sup -6}-M aqueous solution of As{sub 2}O{sub 3} containing 1 mg of carbon L{sup -1} HM. Arsenic adsorbs strongly on Pt in the presence of HM or during sequential specific adsorption with HM.

  4. Competitive ligand exchange between Cu-humic acid complexes and methanobactin.

    Science.gov (United States)

    Pesch, M-L; Hoffmann, M; Christl, I; Kraemer, S M; Kretzschmar, R

    2013-01-01

    Copper has been found to play a key role in the physiology of methanotrophic micro-organisms, and methane oxidation may critically depend on the availability of Cu. In natural environments, such as soils, sediments, peat bogs, and surface waters, the presence of natural organic matter (NOM) can control the bioavailability of Cu by forming strong metal complexes. To promote Cu acquisition, methanotrophs exude methanobactin, a ligand known to have a high affinity for Cu. In this study, the capability of methanobactin for Cu acquisition from NOM was investigated using humic acid (HA) as a model substance. The kinetics of ligand exchange between Cu-HA and methanobactin was observed by UV-vis spectroscopy, and the speciation of Cu bound to methanobactin was determined by size-exclusion chromatography coupled to an ICP-MS. The results showed that Cu was mobilized from HA by a fast ligand exchange reaction following a second-order rate law with first-order kinetics for both methanobactin and Cu-HA complexes. The reaction rates decreased with decreasing temperature. Equilibrium experiments indicated that methanobactin was not sorbed to HA and proved that methanobactin is competitive with HA for Cu binding by forming strong 1:1 Cu-methanobactin complexes. Consequently, our results demonstrate that methanobactin can efficiently acquire Cu in organic-rich environments. © 2012 Blackwell Publishing Ltd.

  5. High efficient removal of mercury from aqueous solution by polyaniline/humic acid nanocomposite

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Ya; Li Qin; Sun Li; Tang Rong [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093 (China); Zhai Jianping, E-mail: jpzhai@nju.edu.cn [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093 (China)

    2010-03-15

    A composite sorbent PANI/HA was prepared by adding humic acid (HA) into chemical oxidation process of polyaniline (PANI). The sorbent was characterized by BET analysis, transmission electron microscopy, and FT-IR spectra. Batch adsorption results showed that the sorbent had high affinity to Hg(II) in aqueous solutions. The adsorption kinetics results of Hg(II) showed that the adsorption reached equilibrium within 200 min and adsorption rates could be described by pseudo-second-order kinetics. Sorption of Hg(II) to PANI/HA agreed well to the Langmuir adsorption model at different ionic strengths with the maximum adsorption capacity of 671 mg g{sup -1} (I = 0.20 M). The experimental results showed solution pH values had a major impact on Hg(II) adsorption and with the help of HA the sorbent can effectively remove Hg(II) in a wide pH range (pH 4-7.5). An adsorption mechanism was proposed based on the XPS results.

  6. 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.

  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. Elemental and spectroscopic characterization of humic-acid-like compounds during composting of olive mill by-products.

    Science.gov (United States)

    Droussi, Zainab; D'Orazio, Valeria; Hafidi, Mohamed; Ouatmane, Aaziz

    2009-04-30

    Humic acids (HAs) were isolated at different stages of composting from two piles of solid olive mill residues (SOR) treated for the first 30 days with tap water (pile C1) or olive mill wastewater (pile C2), for a total composting period of 9 months. The HA fractions were characterized by elemental analysis, UV-visible, Fourier transform infrared and fluorescence spectroscopy in order to monitor humification process and the maturity of the composts. As composting proceeded, the elemental composition of the humic acids showed a decrease in C and H content, and in the C/N ratio, and an increase in N and O contents and in the C/H and O/C ratios. These changes could be attributed to a loss of aliphatic groups and to an increase of aromatic character, polycondensation and degree of oxidation of the HAs. Spectroscopic data agree and support these results, suggesting that the chemical and structural features of the HAs of both composts tend to reach those typical of native soil HAs, that is compounds with a high degree of humification and a high molecular weight and complexity. Therefore, both composting processes seem suitable to produce well-humified organic matter, with important benefits for their use in soil amendment. No differences appeared between the two treatments concerning the humic character of the two final composts.

  9. 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).

  10. Characterization of competitive binding of Eu(III)/Cu(II) and Eu(III)/Ca(II) to Gorleben humic acid

    Energy Technology Data Exchange (ETDEWEB)

    Marang, L.; Reiller, P.E. [CEA Saclay, Lab Speciat Radionucledies and Mol, DEN, DANS, DPC, SECR, 91 - Gif sur Yvette (France); Marang, L.; Benedetti, M.F. [Univ Paris Diderot, Lab Geochim Eaux, IPGP, F-75251 Paris 05 (France); Marang, L.; Benedetti, M.F. [CNRS, UMR 71574, F-75251 Paris 05 (France); Eidner, S.; Kumke, M. [Univ Potsdam, Inst Chem, D-14476 Potsdam (Germany)

    2009-06-15

    Complete text of publication follows: In an area that contains high concentrations of natural organic matter, it is expected to play an important role on the speciation of trivalent radionuclides. Competitive interactions with H{sup +} and major cations, e.g. Ca{sup 2+} or Mg{sup 2+}, could influence these metals transport and bioavailability. Competitive experiments between Eu{sup 3+} and cations which can bind differently to humic substances, would bring an improved understanding of the competitive mechanisms. The aim of this study is to acquire data for Eu(III)/Cu(II) and Eu(III)/Ca(II) competitive binding to a sedimentary-originated humic acid (Gorleben, Germany). The NICA-Donnan parameters [1] for Ca(II), Cu(II), and Eu(III) obtained from competitive binding experiments using Ca{sup 2+} or Cu{sup 2+} ion selective electrodes (ISE), were used to model time-resolved luminescence spectroscopy (TRLS) measurements. Then the TRL spectra and decay times were interpreted to check the consistency of the modelling. From ISE data, Eu(III) and Cu(II) are in direct competition for the same type of sites, whereas Ca(II) has an indirect influence through electrostatic binding. The spectroscopic interpretation of the competition experiments showed two strikingly different environments for the Eu(III)/Cu(II) and Eu(III)/Ca(II) systems. Cu(II) seems to expel more effectively Eu(III) into an aqueous like environment within the humic acid structure, i.e., the Donnan phase, and to the aqueous phase as free Eu{sup 3+}. This is evidenced both from the spectra as well as from the decrease in the luminescence decay times. Moreover, Ca(II) causes a slighter modification of the chemical environment of the humic-complexed Eu(III). [1] Kinniburgh et al. (1999) Colloids Surf. A 151, 147-166

  11. 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.

  12. Effect of humic acid, fulvic acid, pH, ionic strength and temperature on {sup 63}Ni(II) sorption to MnO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Sheng, G.; Wang, X. [School of Nuclear Science and Engineering, North China Electric Power Univ., BJ (China); Key Lab. of Novel Thin Film Solar Cells, Inst. of Plasma Physics, Chinese Academy of Sciences, Hefei (China); Hu, J.; Yang, S.; Ren, X.; Li, J. [Key Lab. of Novel Thin Film Solar Cells, Inst. of Plasma Physics, Chinese Academy of Sciences, Hefei (China); Jin, H. [National Synchrotron Radiation Lab., Univ. of Science and Technology of China, Hefei, AH (China); Chen, Y. [School of Nuclear Science and Engineering, North China Electric Power Univ., BJ (China)

    2010-07-01

    The effects of pH, ionic strength, temperature, humic acid (HA) and fulvic acid (FA) on the sorption of radionuclide {sup 63}Ni(II) to MnO{sub 2} have been investigated by using batch techniques. The results indicated that the sorption of {sup 63}Ni(II) on MnO{sub 2} is obviously dependent on pH values but independent of ionic strength. The presence of HA/FA strongly enhances the sorption of {sup 63}Ni(II) on MnO{sub 2} at low pH values, whereas reduces {sup 63}Ni(II) sorption at high pH values. The sorption of {sup 63}Ni(II) on MnO{sub 2} is attributed to inner-sphere surface complexation rather than outer-sphere surface complexation or ion exchange. The diffuse layer model (DLM) is used to simulate the experimental data well with the aid of FITEQL 3.2. The thermodynamic parameters ({delta}H{sup 0}, {delta}S{sup 0}, {delta}G{sup 0}) are also calculated from the temperature dependent sorption isotherms, and the results suggest that the sorption of {sup 63}Ni(II) on MnO{sub 2} is a spontaneous and endothermic process. (orig.)

  13. The interactions between humic acids and Pluronic F127 produce nanoparticles useful for pharmaceutical applications

    Energy Technology Data Exchange (ETDEWEB)

    Melo, Bruna Alice Gomes de; Motta, Fernanda Lopes; Santana, Maria Helena Andrade, E-mail: mariahelena.santana@gmail.com [University of Campinas, Development of Biotechnological Processes Laboratory, School of Chemical Engineering (Brazil)

    2015-10-15

    Humic acids (HAs) are macromolecules composed of a large variety of functional groups including phenols and carboxylic acids, which have anti-inflammatory and antioxidant properties. HAs are completely soluble in aqueous medium in alkaline conditions only. At neutral pH, the protonation of the OH/OOH groups causes the formation of micelle-like structures containing a hydrophobic core. Pluronic F127 (PF127) is a nonionic and non-toxic block copolymer with surfactant properties, which are able to interact with HAs through hydrophobic interactions. In this work, these interactions were studied to determine the potential of HA–PF127 structures for pharmaceutical applications. The HAs used was composed of phenol (15.92 %), carboxylic (13.70 %), and other aromatic groups as characterized by {sup 13}C NMR, GC–MS, and FTIR. Initially, the HA–PF127 interactions were identified by a fivefold decrease in the CMC of PF127. The effects of the HA:PF127 molar ratio were studied by adding naturally occurring HAs to PF127 dispersions under mechanical stirring. The highest ratios, 1:8 and 1:80, favored the formation of submicellar aggregates of approximately 100 nm and zeta potentials of −28.37 and −30.23 mV, respectively. HA–PF127 structures were spherical, with a polydispersity of approximately 0.43. These results show that the interactions between HAs and PF127 produce stable nanoparticles. These nanoparticles may be used as a carrier for hydrophobic bioactives and as an antioxidant or anti-inflammatory agent. To the best of our knowledge, this work is the first attempt to develop HA–PF127 nanoparticles.

  14. Humic Acid Metal Cation Interaction Studied by Spectromicroscopy Techniques in Combination with Quantum Chemical Calculations

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-01-01

    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 {sup 5}D{sub 0} {yields} {sup 7}F{sub 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.

  15. 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.

  16. Caracterização de ácidos húmicos de vermicomposto de esterco bovino compostado durante 3 e 6 meses Caracterization of humic acids from vermicompost of cattle manure composting by 3 and 6 months

    Directory of Open Access Journals (Sweden)

    Maria Diva Landgraf

    1999-07-01

    Full Text Available The main objective of this research was the characterization of the humic fractions isolated from vermicomposting, originating from cattle manure and treated with Eisenea foetida or Lumbricus rubellus, during 3 and 6 months. Elemental analysis and Infrared and UV-vis spectroscopy were used for their characterizations. The results obtained shown that both humic acids are very similar, but six-month humic acid shown lower percentage of organic material than three month humic acid. The spectroscopy analysis shown that the humic acid studied can be compared with other humic acids reported in the literature. By comparing both vermicomposts, the one produced in three months presents a great potential as fertilizer and it is more economical than the vermicompost produced during a six month period.

  17. Production of humic acids from oil palm empty fruit bunch by submerged fermentation with Trichoderma viride: cellulosic substrates and nitrogen sources.

    Science.gov (United States)

    Motta, F L; Santana, M H A

    2013-01-01

    The novelty of this study was to produce humic acids by submerged fermentation of empty fruit bunch (EFB) with Trichoderma viride and to investigate the effects of the cellulosic substrates and the organic sources of nitrogen on the biotechnological production of these acids. The results obtained indicate the potential application of EFB, a waste of oil palm processing, for humic acids production. Because EFB contains cellulose, hemicellulose and lignin, fermentations were also performed using these polymers as carbon sources, separately or in combination. After 120 h of fermentation, significant production of humic acids was observed only in cultures containing either EFB or a mixture of the three polymers. Use of either potato peptone or yeast extract as a nitrogen source yielded nearly identical patterns of fungal growth and production of humic acids. The data obtained from microscopic imaging of T. viride growth and sporulation in EFB, coupled with the determined rates of production of humic acids indicated that the production of these acids is related to T. viride sporulation. © 2013 American Institute of Chemical Engineers.

  18. TiO2 Nanoparticles Aggregation and Disaggregation in Presence of Alginates and Humic Acids: pH and Concentration Effects on Suspension Stability

    Science.gov (United States)

    Loosli, Frédéric; Le Coustumer, Philippe; Stoll, Serge

    2013-04-01

    The behavior of manufactured TiO2 nanoparticles is studied here in a systematic way as a function of pH and in the presence of Suwannee river humic acids and alginate, at variable concentrations, which represent two major components found in aquatic systems. TiO2 nanoparticles aggregation, disaggregation and stabilization are investigated using dynamic light scattering and electrophoretic experiments allowing the measurement and evolution determination of z-average hydrodynamic diameters and zeta potential values. Stability of the TiO2 nanoparticles is carried out by considering three pH-dependent electrostatic scenarios (below the point of zero charge of the nanoparticles, at the point of zero charge and above it). In the first scenario, when pH is below the point of zero charge of the TiO2 nanoparticles, nanoparticles exhibit a positively charged surface whereas alginate and Suwannee river humic acids are negatively charged. Fast adsorption at the TiO2 nanoparticles occurs, promotes surface charge neutralization and aggregation and, by increasing further Alginate and Suwannee river humic acids, results in charge inversion and thus stabilization of TiO2 nanoparticles. In the second electrostatic scenario, at the pH of the TiO2 surface charge neutralization, TiO2 nanoparticles are rapidly forming aggregates and adsorption of alginate and Suwannee river humic acid on aggregates surface leads to the partial disaggregation of aggregates. In the third electrostatic scenario, when nanoparticles, alginates and Suwannee river humic acids are negatively charged a small amount of Suwannee river humic acids is adsorbed via hydrophobic interactions. It is found that the fate and behavior of individual and aggregated TiO2 nanoparticles in presence of environmental compounds are strongly dependent on the electrostatic, concentration ratio, and to a less extend to the amphiphilic compounds character and that environmental aquatic concentration ranges of humic acids and

  19. TiO2 nanoparticles aggregation and disaggregation in presence of alginate and Suwannee River humic acids. pH and concentration effects on nanoparticle stability.

    Science.gov (United States)

    Loosli, Frédéric; Le Coustumer, Philippe; Stoll, Serge

    2013-10-15

    The behavior of manufactured TiO2 nanoparticles is studied in a systematic way in presence of alginate and Suwannee River humic acids at variable concentrations. TiO2 nanoparticles aggregation, disaggregation and stabilization are investigated using dynamic light scattering and electrophoretic experiments allowing the measurement of z-average hydrodynamic diameters and zeta potential values. Stability of the TiO2 nanoparticles is discussed by considering three pH-dependent electrostatic scenarios. In the first scenario, when pH is below the TiO2 nanoparticle point of zero charge, nanoparticles exhibit a positively charged surface whereas alginate and Suwannee River humic acids are negatively charged. Fast adsorption at the TiO2 nanoparticles occurs, promotes surface charge neutralization and aggregation. By increasing further alginate and Suwannee River humic acids concentrations charge inversion and stabilization of TiO2 nanoparticles are obtained. In the second electrostatic scenario, at the surface charge neutralization pH, TiO2 nanoparticles are rapidly forming aggregates. Adsorption of alginate and Suwannee River humic acids on aggregates leads to their partial fragmentation. In the third electrostatic scenario, when nanoparticles, alginate and Suwannee River humic acids are negatively charged, only a small amount of Suwannee River humic acids is adsorbed on TiO2 nanoparticles surface. It is found that the fate and behavior of individual and aggregated TiO2 nanoparticles in presence of environmental compounds are mainly driven by the complex interplay between electrostatic attractive and repulsive interactions, steric and van der Waals interactions, as well as concentration ratio. Results also suggest that environmental aquatic concentration ranges of humic acids and biopolymers largely modify the stability of aggregated or dispersed TiO2 nanoparticles. Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. Identification of humic acid-like and fulvic acid-like natural organic matter in river water using fluorescence spectroscopy.

    Science.gov (United States)

    Peiris, R H; Budman, H; Moresoli, C; Legge, R L

    2011-01-01

    Identifying the extent of humic acid (HA)-like and fulvic acid (FA)-like natural organic matter (NOM) present in natural water is important to assess disinfection by-product formation and fouling potential during drinking water treatment applications. However, the unique fluorescence properties related to HA-like NOM is masked by the fluorescence signals of the more abundant FA-like NOM. For this reason, it is not possible to accurately characterize HA-like and FA-like NOM components in a single water sample using direct fluorescence EEM analysis. A relatively simple approach is described here that demonstrates the feasibility of using a fluorescence excitation-emission matrix (EEM) approach for identifying HA-like and FA-like NOM fractions in water when used in combination with a series of pH adjustments and filtration steps. It is demonstrated that the fluorescence EEMS of HA-like and FA-like NOM fractions from the river water sample possessed different spectral properties. Fractionation of HA-like and FA-like NOM prior to fluorescence analysis is therefore proposed as a more reasonable approach.

  1. Adsorption of chloroacetanilide herbicides on soil and its components. III. Influence of clay acidity, humic acid coating and herbicide structure on acetanilide herbicide adsorption on homoionic clays.

    Science.gov (United States)

    Liu, Wei-ping; Fang, Zhuo; Liu, Hui-jun; Yang, Wei-chun

    2002-04-01

    Adsorption of chloroacetanilide herbicides on homoionic montmorillonite, soil humic acid, and their mixtures was studied by coupling batch equilibration and FT-IR analysis. Adsorption isotherms of acetochlor, alachlor, metolachlor and propachlor on Ca(2+)-, Mg(2+)-, Al(3+)- and Fe(3+)-saturated clays were well described by the Freundlich equation. Regardless of the type of exchange cations, Kf decreased in the order of metolachlor > acetolachlor > alachlor > propachlor on the same clay. FT-IR spectra showed that the carbonyl group of the herbicide molecule was involved in binding, probably via H-bond with water molecules in the clay interlayer. The type and position of substitutions around the carbonyl group may have affected the electronegativity of oxygen, thus influencing the relative adsorption of these herbicides. For the same herbicide, adsorption on clay increased in the order of Mg2+ < Ca2+ < Al3+ < or = Fe3+ which coincided with the increasing acidity of homoionic clays. Acidity of cations may have affected the protonation of water, and thus the strength of H-bond between the clay water and herbicide. Complexation of clay and humic acid resulted in less adsorption than that expected from independent adsorption by the individual constituents. The effect varied with herbicides, but the greatest decrease in adsorption occurred at a 60:40 clay-to-humic acid ratio for all the herbicides. Causes for the decreased adsorption need to be characterized to better understand adsorption mechanisms and predict adsorption from soil compositions.

  2. 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, 13C 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.

  3. Separation of molecular constituents from a humic acid by solid-phase extraction following a transesterification reaction.

    Science.gov (United States)

    Fiorentino, Gabriella; Spaccini, Riccardo; Piccolo, Alessandro

    2006-02-15

    A selective removal of humic constituents involved in ester groups was conducted by a boron trifluoride-methanol transesterification reaction after removal of structurally unbound lipids. An analytical separation of subfractions containing specific classes of compound liberated from the humic matrix simplifies their identification by gas chromatography-mass spectrometry. We compared the traditional liquid-liquid separation into phenolic and aliphatic fractions with the modern and versatile fractionation technique using solid-phase extraction (SPE) on aminopropyl-bonded phases. Our results showed that both methods ensured separation of the same compounds, such as di- and tri-hydroxyalkanoic acids, alpha-, beta- and omega-hydroxy fatty acids, alkanoic acids, alpha,omega-alkanedioic acids, n-alkanols, phenolic acids and sterols. Moreover, the SPE method not only provided a larger recovery of compounds, but involved smaller sample and solvent requirements, and larger ease and rapidity of sample handling than the traditional liquid-liquid separation. The SPE method should be thus recommended in structural studies of natural organic matter.

  4. 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.

  5. 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..

  6. 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.

  7. The Effect of Humic Acid Substances on the Thyroid Function and Structure in Lead Poisoning

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    A Sahin

    Full Text Available ABSTRACT Lead (Pb is a heavy metal, which adversely affects thyroid gland function and structure. Due to its high molecular weight and abundant functional groups, humic acid substances (HAS can form chelates with heavy metals. The experiment was conducted to evaluate the prophylactic effect of HAS on thyroid hormone levels and histopathological lesions of laying hens exposed to lead (Pb poisoning. After a week of adaptation, 192 Lohmann White laying hens (25 weeks of age were fed one of four diets: a basal diet (BD or the BD with HAS (0.15%, with Pb (0.3 g/kg, or with both. Experimental groups were replicated in 12 cages, with four hens each. Pb poisoning did not alter triiodothyronine (FT3; 3.22 ± 0.20 ng/dL or thyroxine (FT4; 0.71 ± 0.08 ng/dL concentrations, but caused a 167% increase in thyroid stimulating hormone (TSH concentration. HAS supplementation returned the high TSH levels of hens exposed to Pb poisoning to normal values. Degenerative changes in the epithelial cells of the thyroid gland of the hens exposed to Pb poisoning were evidenced. Connective tissue cells in the interfollicular area and total amount of colloids with partially atrophic follicles were observed. These histopathological findings were less severe when HAS was added to the diet. In conclusion, HAS alleviates the effects of Pb poisoning on thyroid gland function and structure, possibly preventing its internalization by the tissue by forming chelates and exerting anti-inflammatory effects.

  8. Reducing THMFP by H2O2/UV oxidation for humic acid of small molecular weight.

    Science.gov (United States)

    Yen, Hsing Yuan; Yen, Li Shuang

    2015-01-01

    In this study, the merits of using H2O2/UV oxidation for reducing trihalomethane formation potential (THMFP), colour, and dissolved organic carbon (DOC) of smaller molecular humic acid were investigated, especially the energy consumption based on EEO. The results show that THMFP decreases by increasing oxidation time, H2O2 dose and UV intensity. The reaction constant in descending order is kColour>kDOC>kTHMFP. Furthermore, EEO shows three trends. First, it decreases as H2O2 dose increases. That is, by increasing the amount of H2O2 dose, the electrical energy efficiency becomes better. Second, EEO,9 W>EEO,13 W, implying that higher UV power would result in a higher electrical energy efficiency. Third, EEO,THMFP>EEO,DOC>EEO,colour. That is, the electric energy efficiency is the best for colour removal, second for DOC removal, and third for THMFP reduction. The operation costs for 90% removal of colour, DOC, and THMFP are from 0.31 to 0.69, from 0.78 to 1.72, and from 1.11 to 2.29 US$/m3, respectively. However, reducing THMs to Taiwan's drinking water standard of 80 µg/L needs only 0.25-0.60 US$/m3. Therefore, the condition with UV of 9 W, H2O2 of 50 mg/L, and oxidation time of 23 min can be applied for THMs reduction as the cost is the smallest of 0.25 US$/m3, even lower than current Taiwan's drinking water price of 0.3 US$/m3.

  9. Effect of environmental factors on the complexation of iron and humic acid.

    Science.gov (United States)

    Fang, Kai; Yuan, Dongxing; Zhang, Lei; Feng, Lifeng; Chen, Yaojin; Wang, Yuzhou

    2015-01-01

    A method of size exclusion chromatography coupled with ultraviolet spectrophotometry and off-line graphite furnace atomic absorption spectrometry was developed to assess the complexation properties of iron (Fe) and humic acid (HA) in a water environment. The factors affecting the complexation of Fe and HA, such as ionic strength, pH, temperature and UV radiation, were investigated. The Fe-HA complex residence time was also studied. Experimental results showed that pH could influence the deprotonation of HA and hydrolysis of Fe, and thus affected the complexation of Fe and HA. The complexation was greatly disrupted by the presence of NaCl. Temperature had some influence on the complexation. The yield of Fe-HA complexes showed a small decrease at high levels of UV radiation, but the effect of UV radiation on Fe-HA complex formation at natural levels could be neglected. It took about 10 hr for the complexation to reach equilibrium, and the Fe-HA complex residence time was about 20 hr. Complexation of Fe and HA reached a maximum level under the conditions of pH 6, very low ionic strength, in the dark and at a water temperature of about 25°C, for 10 hr. It was suggested that the Fe-HA complex could form mainly in freshwater bodies and reach high levels in the warm season with mild sunlight radiation. With changing environmental parameters, such as at lower temperature in winter or higher pH and ionic strength in an estuary, the concentration of the Fe-HA complex would decrease. Copyright © 2014. Published by Elsevier B.V.

  10. The pH-dependence of organofluorine binding domain preference in dissolved humic acid.

    Science.gov (United States)

    Longstaffe, James G; Courtier-Murias, Denis; Simpson, André J

    2013-01-01

    In this study we explore the relationship between solution pH and the distribution of the binding interactions at different domains of a dissolved humic acid (HA) for three xenobiotics: pentafluoroaniline (PFA), pentafluorophenol (PFP), and hexafluorobenzene (HFB). The components of HA where xenobiotic interactions occur are identified using the (1)H{(19)F} Reverse Heteronuclear Saturation Transfer Difference (RHSTD) Nuclear Magnetic Resonance (NMR) spectroscopy experiment. At low pH, PFA and PFP interact preferentially with aromatic components of HA. Increasing pH reduces this preference. Conversely, HFB interacts with all components of HA equally, across the entire pH range. The possible roles of both aromatic-specific interactions and conformational changes of HA behind these observations are explored. It is shown that T-oriented π-π interactions at π-electron accepting HA structures are slightly stronger for PFA and PFP than for HFB. Using DOSY NMR it is shown that the pH-dependence of the interactions is correlated with changes in the conformation of the carbohydrate components of HA rather than with the aromatic components. It is argued that the observed preference for aromatic HA is caused by restricted access to the non-aromatic components of HA at low pH. These HA components form tightly bound hydrophobic domains due to strong inter- and intra-molecular hydrogen bonds. At high pH, these structures open up, making them more available for interactions with polar compounds. Copyright © 2012 Elsevier Ltd. All rights reserved.

  11. Speciation of copper-humic acid in zeolite Y during extraction with a RTIL

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Hsin-Liang, E-mail: hlhuang@nuu.edu.t [Department of Safety, Health and Environmental Engineering, National United University, Miao-Li City 360, Taiwan (China); Jyun Chen, Yan [Department of Safety, Health and Environmental Engineering, National United University, Miao-Li City 360, Taiwan (China)

    2010-07-21

    Chemical structure of copper chelated with humic acid (Cu-HA) in the micro-pores of zeolite Y (to simulate micropores in copper contaminated soils) and extracted with a room temperature ionic liquid (RTIL) ([C{sub 4}mim][PF{sub 6}], 1-butyl-3-methylimidazolium hexafluorophosphate) has been studied by X-ray absorption (near edge structure (XANES) and Fourier transformed extended X-ray absorption fine structure (EXAFS)) spectroscopy. At the temperature of 298 K, within 30 min, about 84% of Cu-HA in Y can be extracted by the RTIL. The XANES spectra reveal that a small amount of Cu(II)-HA (7%), adsorbed Cu(II) (Cu{sub (ads)}{sup 2+}) (5%) and Cu[mim]{sub 4}{sup 2+} (4%), which are not extracted, are found in Y. In the copper extracted RTIL, 75% of Cu(II)-HA in Y are converted to Cu[mim]{sub 4}{sup 2+} during extraction. About 17% of Cu(II)-HA is also found in the RTIL. Therefore, at least three reaction paths may be involved in the extraction process: (1) extraction of Cu(II)-HA in the RTIL, (2) Cu{sup 2+} (formed from dissociation of Cu(II)-HA in the RTIL) adsorbed on Y, and (3) inter-conversion of Cu(II)-HA to Cu[mim]{sub 4}{sup 2+} in the RTIL. The refined EXAFS data indicate that the Cu-O bond distance in the Y and RTIL phases is 1.94 A with an average coordination number (CN) of 3.4. Note that Cu[mim]{sub 4}{sup 2+} in the RTIL processes a Cu-N bond distance of 1.96 A and a CN of 4.1.

  12. 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.

  13. 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.

  14. Influence of humic substances on enhanced remediation of soil polluted by a copper-nickel smelter

    Science.gov (United States)

    Tregubova, Polina; Turbaevskaya, Valeria; Korneecheva, Mariya; Kupriyanova, Yuliya; Koptsik, Galina

    2017-04-01

    The problem of technogenic contamination through the anthropogenic activity is quite urgent nowadays. Long-term air pollution with sulphur dioxide and heavy metals (HM) by injuring vegetation and inhibition of plant and soil microorganisms growth and activity causes appearance of the barren areas - highly damaged eroded ecosystems requiring remediation. There are a lot of remediation ways, but an appropriate restoration method, which does not expensive, does not demand special technical support and corresponds to the natural conditions of soil development is still open to question. We suggest application of exogenous humic substances as the possible environmentally friendly solution of HM toxicity problem and soil health restoration. Using of humates can result in the improvement of soil properties, localization of contamination by decreasing of HM mobility and bioavailability through binding them in relatively immobile complexes, and in stabilization of organic pool. But practice of scientific society as well as our previous investigations demonstrates ambiguous influence of exogenic humic substances on the behavior of HM depending on origin, doses, molecular weight of organic matter and state of microorganisms. In this research we have provided series of short-term (45 days) experiments dedicated to the evaluation of suitable doses of humates of different origin - coal and peat - inoculated by nitrogen fixers and mycorhizae-forming fungi in comparison with lime and NPK-fertilizer on the properties of contaminated soil and mobility of HM. The object of investigation was Al-Fe-humus abrazems from the vicinity of mining-and-metallurgical integrated work located in the Kola Peninsula, Russia. This soil is characterized by the absence of vegetation, complete loss of the organic horizon in result of the erosion processes, low pH (pH H2O 4.1-5.0), low exchangeable acidity (0.8-1.6 cmolc/kg), and depletion of organic mater (content of total carbon is 0.3-0.5%). The main

  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. Synthesis of walnut shell modified with titanium dioxide and zinc oxide nanoparticles for efficient removal of humic acid from aqueous solutions.

    Science.gov (United States)

    Naghizadeh, Ali; Shahabi, Habibeh; Ghasemi, Fatemeh; Zarei, Ahmad

    2016-12-01

    The main aim of this research was to study the efficiency of modified walnut shell with titanium dioxide (TiO2) and zinc oxide (ZnO) in the adsorption of humic acid from aqueous solutions. This experimental study was carried out in a batch condition to determine the effects of factors such as contact time, pH, humic acid concentration, dose of adsorbents (raw walnut shell, modified walnut shell with TiO2 and ZnO) on the removal efficiency of humic acid. pHzpc of raw walnut shell, walnut shell modified with TiO2 and walnut shell modified with ZnO were 7.6, 7.5, and 8, respectively. The maximum adsorption capacity of humic acid at concentration of 30 mg/L, contact time of 30 min at pH = 3 in an adsorbent dose of 0.02 g of walnut shell and ZnO and TiO2 modified walnut shell were found to be 35.2, 37.9, and 40.2 mg/g, respectively. The results showed that the studied adsorbents tended to fit with the Langmuir model. Walnut shell, due to its availability, cost-effectiveness, and also its high adsorption efficiency, can be proposed as a promising natural adsorbent in the removal of humic acid from aqueous solutions.

  17. 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.

  18. 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

  19. 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

  20. Effect of PVP on the characteristic of modified membranes made from waste PET bottles for humic acid removal.

    Science.gov (United States)

    Arahman, Nasrul; Fahrina, Afrillia; Amalia, Sastika; Sunarya, Rahmat; Mulyati, Sri

    2017-01-01

    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/m (2).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.

  1. 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.

  2. 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

  3. Application of excitation-emission fluorescence matrices and UV/Vis absorption to monitoring the photocatalytic degradation of commercial humic acid

    Energy Technology Data Exchange (ETDEWEB)

    Valencia, Sergio, E-mail: hvalens@gmail.com [Procesos Fisicoquimicos Aplicados, Universidad de Antioquia, Carrera 53 61-30, Medellin (Colombia); Marin, Juan M.; Restrepo, Gloria [Procesos Fisicoquimicos Aplicados, Universidad de Antioquia, Carrera 53 61-30, Medellin (Colombia); Frimmel, Fritz H., E-mail: fritz.frimmel@kit.edu [BereichWasserchemie, Engler-Bunte-Institut, Karlsruher Institut fuer Technology (KIT), 7631, Karlsruhe (Germany)

    2013-01-01

    This study reports the use of excitation-emission matrix (EEM) fluorescence and UV/Vis spectroscopy to monitor the changes in the composition and reactivity of Aldrich humic acids (Aldrich HA) as a model compound for natural organic matter (NOM) during photocatalytic degradation. Degussa P-25 titanium dioxide (TiO{sub 2}) and a solar UV-light simulator (a batch reactor) were used. The photocatalysis shifted the fluorescence maxima of EEMs of Aldrich HA toward shorter wavelengths, which implied that the photocatalytic degradation of commercial Aldrich HA caused the breakdown of high molecular weight components and the formation of lower molecular weight fractions. In addition, the fluorescence intensity of fulvic- and humic-like Aldrich HA presented a strong correlation with dissolved organic carbon (DOC), specific UV absorbance (SUVA) parameters, trihalomethane formation potential (THMFP), and organically bound halogens absorbable on activated carbon formation potential (AOXFP). Fluorescence spectroscopy was shown to be a powerful tool for monitoring of the photocatalytic degradation of HA. Highlights: Black-Right-Pointing-Pointer There is a strong correlation between the fluorescence intensity of humic acids and DOC. Black-Right-Pointing-Pointer HA-like and FA-like fluorescence intensity and SUVA show strong linear correlation. Black-Right-Pointing-Pointer Humic acids with high fluorescence intensity imply high formation of DBPs. Black-Right-Pointing-Pointer Humic acid photocatalysis lead to a decrease in the fluorescence intensity of EEMs. Black-Right-Pointing-Pointer Fluorescence spectroscopy is a powerful tool to monitor HA photocatalytic removal.

  4. 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) 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 proportion of uranyl-Fh inner-sphere sorption complexes decreased relative to uranyl-ESHA or uranyl-SRFA complexes, which comprised up

  5. 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)

  6. 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

  7. Compositional and functional features of humic acid-like fractions from vermicomposting of sewage sludge and cow dung

    Energy Technology Data Exchange (ETDEWEB)

    Li Xiaowei [State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092 (China); Xing Meiyan, E-mail: xmy5000@163.com [State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092 (China); Yang Jian; Huang Zhidong [State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092 (China)

    2011-01-30

    The chemical changes occurring in five different substrates of sewage sludge spiked with different proportions of cow dung after vermicomposting with Eisenia foetida for 90 days were investigated. Their humic acid-like (HAL) fractions were isolated to determine the elemental and functional composition, and structural and functional characteristics using ultraviolet/visible, Fourier transform infrared (FT-IR) and fluorescence spectroscopies and scanning electron microscopy. After vermicomposting, the total organic C and C/N ratio decreased, and the total extractable C and humic acid (HA) C increased in all substrates. In the HAL fractions, the C and H contents, C/N and C/O and aliphatic structures, proteinaceous components and carbohydrates decreased, while the O and N and acidic functional group contents and C/H ratio, aromaticity and polycondensation structures increased. Further, the results suggest that the addition of cow dung to sewage sludge could improve the quality of organic matter humification of the substrates. The structures of HAL fractions in vermicomposts resembled those typical of soil HA, especially the vermicompost of cow dung alone. Scanning electron microscopy showed the microstructure of HAL fraction in final product became close-grained and lumpy. Overall results indicate that vermicomposting was an efficient technology for promoting organic matter (OM) humification in sewage sludge and cow dung alone, as well as in mixtures of both materials, improving their quality and environmental safety as a soil OM resource for utilization as soil amendments.

  8. Modification of humic acid by ether functional group as biosorbent to Au(III) adsorption in the presence of Sn(II) and Ni(II)

    Science.gov (United States)

    Yanti, Ika; Winata, Wahyu Fajar; Sudiono, Sri; Triyono

    2017-03-01

    Modification of humic acid on the phenolic functional group with dimethylsulfate (DMS) for adsorption Au(III) in the presence of Sn(II) and Ni(II) have been conducted. Ash content was analyzed and characterized by Fourier-Transform Infrared (FTIR). Determination of Au(III) adsorption in the presence of Sn(II) and Ni(II) was conducted by Atomic Adsorption Spectroscopy (AAS). The isolated humic acid has 19.8% ash content and after purification has 0.6% ash content, etherified humic acid (EHAs) has 1.4% ash content. Adsorption percentage of Au(III) in the presence of Sn(II) and Ni(II) by EHAs decreased until 4.936% and 41.782% respectively. The addition of Sn(II) and Ni(II) as competitors of Au(III) in the Au(III) adsorption by using EHAs, were affect the percentage of Au(III) adsorption.

  9. 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...

  10. 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),

  11. Effect of humic matter on metal adsorption onto clay materials: testing the linear additive model.

    Science.gov (United States)

    Lippold, Holger; Lippmann-Pipke, Johanna

    2009-10-13

    Migration of contaminants with low affinity for the aqueous phase is essentially governed by interaction with mobile carriers such as humic colloids. Their impact is, however, not sufficiently described by interaction constants alone since the humic carriers themselves are subject to a solid-liquid distribution that depends on geochemical parameters. In our study, co-adsorption of the REE terbium (as an analogue of trivalent actinides) and humic acid onto three clay materials (illite, montmorillonite, Opalinus clay) was investigated as a function of pH. (160)Tb(III) and (131)I-labelled humic acid were employed as radiotracers, allowing experiments at very low concentrations to mimic probable conditions in the far-field of a nuclear waste repository. Humate complexation of Tb was examined by anion and cation exchange techniques, also considering competitive effects of metals leached from the clay materials. The results revealed that desorption of metals from clay barriers, occurring in consequence of acidification processes, is generally counteracted in the presence of humic matter. For all clay materials under study, adsorption of Tb was found to be enhanced in neutral and acidic systems with humic acid, which is explained by additional adsorption of humic-bound Tb. A commonly used composite approach (linear additive model) was tested for suitability in reconstructing the solid-liquid distribution of Tb in ternary systems (Tb/humic acid/clay) on the basis of data determined for binary subsystems. The model can qualitatively explain the influence of humic acid as a function of pH, but it failed to reproduce our experimental data quantitatively. It appears that the elementary processes (metal adsorption, metal-humate complexation, humic acid adsorption) cannot be considered to be independent of each other. Possible reasons are discussed.

  12. Effect of humic matter on metal adsorption onto clay materials: Testing the linear additive model

    Science.gov (United States)

    Lippold, Holger; Lippmann-Pipke, Johanna

    2009-10-01

    Migration of contaminants with low affinity for the aqueous phase is essentially governed by interaction with mobile carriers such as humic colloids. Their impact is, however, not sufficiently described by interaction constants alone since the humic carriers themselves are subject to a solid-liquid distribution that depends on geochemical parameters. In our study, co-adsorption of the REE terbium (as an analogue of trivalent actinides) and humic acid onto three clay materials (illite, montmorillonite, Opalinus clay) was investigated as a function of pH. 160Tb(III) and 131I-labelled humic acid were employed as radiotracers, allowing experiments at very low concentrations to mimic probable conditions in the far-field of a nuclear waste repository. Humate complexation of Tb was examined by anion and cation exchange techniques, also considering competitive effects of metals leached from the clay materials. The results revealed that desorption of metals from clay barriers, occurring in consequence of acidification processes, is generally counteracted in the presence of humic matter. For all clay materials under study, adsorption of Tb was found to be enhanced in neutral and acidic systems with humic acid, which is explained by additional adsorption of humic-bound Tb. A commonly used composite approach (linear additive model) was tested for suitability in reconstructing the solid-liquid distribution of Tb in ternary systems (Tb/humic acid/clay) on the basis of data determined for binary subsystems. The model can qualitatively explain the influence of humic acid as a function of pH, but it failed to reproduce our experimental data quantitatively. It appears that the elementary processes (metal adsorption, metal-humate complexation, humic acid adsorption) cannot be considered to be independent of each other. Possible reasons are discussed.

  13. Effects of humic substances derived from organic waste enhancement on the growth and mineral nutrition of maize.

    Science.gov (United States)

    Eyheraguibel, B; Silvestre, J; Morard, P

    2008-07-01

    A physico-chemical process has been developed to transform and enhance lignocellulosic waste in liquid humic extracts: humic-like substances (HLS). The aim of this study was to determine the effects of HLS on plant physiology in order to consider their agricultural use as organic fertilizers. The effects of HLS were evaluated on maize seed germination, and their impact on growth, development and mineral nutrition was studied on maize plants cultivated under hydroponic conditions. The experimental results showed that HLS do not increase the percentage and rate of germination but enhance the root elongation of seeds thus treated. Positive effects were also observed on the whole plant growth as well as on root, shoot and leaf biomass. These effects can be related to the high water and mineral consumption of plants undergoing this treatment. The high water efficiency indicated that such plants produce more biomass than non-treated plants for the same consumption of the nutrient solution. Furthermore, the use of HLS induced a flowering precocity and modified root development suggesting a possible interaction of HLS with developmental processes. Considering the beneficial effect of HLS on different stages of plant growth, their use may present various scientific and economic advantages. The physico-chemical transformation of sawdust is an interesting way of enhancing organic waste materials.

  14. 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.

  15. 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

  16. Characterisation of Fe-oxide nanoparticles coated with humic acid and Suwannee River natural organic matter.

    Science.gov (United States)

    Chekli, Laura; Phuntsho, Sherub; Roy, Maitreyee; Shon, Ho Kyong

    2013-09-01

    Iron oxide nanoparticles are becoming increasingly popular for various applications including the treatment of contaminated soil and groundwater; however, their mobility and reactivity in the subsurface environment are significantly affected by their tendency to aggregate. One solution to overcome this issue is to coat the nanoparticles with dissolved organic matter (DOM). The advantages of DOM over conventional surface modifiers are that DOM is naturally abundant in the environment, inexpensive, non-toxic and readily adsorbed onto the surface of metal oxide nanoparticles. In this study, humic acid (HA) and Suwannee River natural organic matter (SRNOM) were tested and compared as surface modifiers for Fe2O3 nanoparticles (NPs). The DOM-coated Fe2O3 NPs were characterised by various analytical methods including: flow field-flow fractionation (FlFFF), high performance size exclusion chromatography (HPSEC) and Fourier transform infrared spectroscopy (FTIR). The stability of the coated NPs was then evaluated by assessing their aggregation and disaggregation behaviour over time. Results showed that both HA and SRNOM were rapidly and readily adsorbed on the surface of Fe2O3 NPs, providing electrosteric stabilisation over a wide range of pH. HPSEC results showed that the higher molecular weight components of DOM were preferentially adsorbed onto the surface of Fe2O3. As SRNOM consists of macromolecules with a higher molecular weight than HA, the measured size of the SRNOM-coated Fe2O3 NPs was 30% larger than the HA-coated Fe2O3 NPs. FTIR results indicated the occurrence of hydrogen bonding arising from electrostatic interaction between the DOM and Fe2O3 NPs. Finally, a stability study showed that after 14 days, small agglomerates and aggregates were formed. The HA-coated Fe2O3 NPs formed agglomerates which were easily disaggregated using a vortex mixer, with the coated NPs returning to their initial size. However, SRNOM-coated Fe2O3 NPs were only partially disaggregated

  17. 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

  18. [Characterizing the interaction between roxarsone and humic acid by fluorescence quenching experiment].

    Science.gov (United States)

    Zhu, Jiang-Peng; Mei, Ting; Peng, Yun; Ge, Si-Yi; Li, Shi-Yin; Wang, Guo-Xiang

    2014-07-01

    In this study, the methods of fluorescence spectroscopy and fluorescence quenching titration technique were used to identify the interactions between humic acid (HA) and roxarsone (ROX). Effects of HA concentration, pH and temperature on the bonding strength between HA and ROX were investigated. The results showed that the four fluorescence peaks (E(x)/E(m) = 300 nm/480 nm, 370 nm/480 nm, 420 nm/500 nm, 460 nm/520 nm, marked as peak A, B, C, D respectively) of HA could be quenched by ROX. The extent of decreases in fluorescence intensities of different peaks was different and followed the order of C > B > A > D. The common logarithm of association constants (lg K) between peak A and ROX increased slightly with the increase of HA concentration and were much larger than the bimolecular quenching constant of O2. It was confirmed that the carboxyl groups and the carboxide groups of HA were quenched statically by ROX. The lg K values fluctuated between 3.55 L x mol(-1) and 3.98 L x mol(-1) when pH ranged from 5.00 to 9.00, and the maximum value occurred at pH 6.00. It might be resulted from the fact that pH could change the formation of ROX and conformation of phenolic hydroxyl groups and carboxyl groups in HA. The lg K values decreased and fluctuated between 2.65 L x mol(-1) and 3.89 L x mol(-1) with temperature ranging from 25.0 degrees C to 55.0 degrees C, which further confirmed the static quenching interaction between HA and ROX. Transient-fluorescence spectrum analyses and liner model simulations revealed that single static quenching was the main mechanism between ROX and the functional groups of fluorescence peak A, B, D in HA, and combined dynamic and static quenching was the main mechanism between ROX and the functional groups of peak C in HA.

  19. Effects of long-term fertilization on soil humic acid composition and structure in Black Soil.

    Directory of Open Access Journals (Sweden)

    Jiuming Zhang

    Full Text Available 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

  20. 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

  1. Characterization of humic acid reactivity modifications due to adsorption onto α-Al2O3.

    Science.gov (United States)

    Janot, Noémie; Reiller, Pascal E; Zheng, Xing; Croué, Jean-Philippe; Benedetti, Marc F

    2012-03-01

    Adsorption of purified Aldrich humic acid (PAHA) onto α-Al(2)O(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