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Removal of heavy metals from waste streams  

Energy Technology Data Exchange (ETDEWEB)

A method for removing heavy metals from effluent water is described comprising performing sequentially the following steps: (a) adding from 7-333 ppm of an anionic surfactant to the effluent water to provide coagulatable heavy metal ion; (b) adjusting the effluent water pH to within the range of 8 to 10, (c) providing from 10-200 ppm of a cationic coagulant to coagulate the heavy metal ion, (d) providing from 0.3 to 5.0 ppm of a polymeric flocculant whereby a heavy metal containing floc is formed for removal from the effluent water, and, (e) then removing the floc from the effluent water, wherein the anionic surfactant is sodium lauryl ether sulfate. The cationic coagulant is selected from the group consisting of diallyl dimethylammonium chloride polymer, epichlorohydrin dimethylamine polymer, ethylene amine polymer, polyaluminum chloride, and alum; and the flocculant is an acrylamide/sodium acrylate copolymer having an RSV greater than 23.

Spence, M.D.; Kozaruk, J.M.; Melvin, M.; Gardocki, S.M.

1988-07-19

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Heavy metal removal and recovery using microorganisms  

Energy Technology Data Exchange (ETDEWEB)

Microorganisms -- bacteria, fungi, and microalgae -- can accumulate relatively large amounts of toxic heavy metals and radionuclides from the environment. These organisms often exhibit specificity for particular metals. The metal content of microbial biomass can be a substantial fraction of total dry weight with concentration factors (metal in dry biomass to metal in solution) exceeding one million in some cases. Both living and inert (dead) microbial biomass can be used to reduce heavy metal concentrations in contaminated waters to very low levels -- parts per billion and even lower. In many respects (e.g. specificity, residual metal concentrations, accumulation factors, and economics) microbial bioremoval processes can be superior to conventional processes, such as ion exchange and caustic (lime or hydroxide) precipitation for heavy metals removal from waste and contaminated waters. Thus, bioremoval could be developed to contribute to the clean-up of wastes at the Savannah River Site (SRS) and other DOE facilities. However, the potential advantages of bioremoval processes must still be developed into practical operating systems. A detailed review of the literature suggests that appropriate bioremoval processes could be developed for the SRS. There is great variability from one biomass source to another in bioremoval capabilities. Bioremoval is affected by pH, other ions, temperature, and many other factors. The biological (living vs. dead) and physical (immobilized vs. dispersed) characteristics of the biomass also greatly affect metal binding. Even subtle differences in the microbial biomass, such as the conditions under which it was cultivated, can have major effects on heavy metal binding.

Wilde, E.W. (Westinghouse Savannah River Co., Aiken, SC (United States)); Benemann, J.R. (Benemann (J.R.), Pinole, CA (United States))

1991-02-01

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Heavy metal removal using reverse osmosis  

Directory of Open Access Journals (Sweden)

Full Text Available The aim of this work was to study reverse osmosis characteristics for copper, nickel and zinc removal from technological aqueoussolutions. Reverse osmosis (RO) is a separation process that uses pressure to force a solution through a membrane that retainsthe solute on one side and allows the pure solvent to pass to the other side. A polyamide thin-film composite membrane TW30-1812-50was used. The difference in flux decline is significant. There is a significant difference in flux decline depending on the anions of usedheavy metal salts. The heavy metal concentration also has a significant influence on the membrane separation. There is alsoa significant difference in flux decline depending on the transmembrane pressure.

Tomáš Bakalár; Milan Búgel; Lucia Gajdošová

2009-01-01

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Heavy metals removal from dredged sediments using electro kinetics  

Directory of Open Access Journals (Sweden)

Full Text Available This study focuses on the use of a remediation process to remove particle-bound recalcitrant pollutants (heavy metals) from dredged harbor sediments which must be previously treated before reuse in civil engineering. Electrokinetic (EK) remediation is generally accepted as one of the most suitable technologies for extracting cationic heavy metals from fine grained sediments. Many batch tests were performed to better understand the capacity of various additives to improve sediment decontamination (when applying a constant voltage gradient of 1 V.cm-1), and the combination of enhancing agents (acids + surfactants) were assessed to obtain an efficient removal of heavy metals. We succeeded in proving that mixing citric acid and a nonionic surfactant (Tween 20), additives which are environmentally friendly, was a good association to enhance heavy metals (Cd, Cr, Cu, Pb and Zn) removal.

Ammami M. T.; Benamar A.; Koltalo F.; Wang H. Q.; LeDerf F.

2013-01-01

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Heavy metal removal potential of dried Salvinia biomass.  

UK PubMed Central (United Kingdom)

Investigations were carried out to evaluate heavy metal adsorption capacity of Salvinia. Batch experiments showed that dry plant biomass possess good potential to adsorb heavy metals such as Ni, Co, Cr, Fe, and Cd. The metal adsorption increased with increase in initial metal concentration. The data obtained fitted well with Freundlich equilibrium isotherm. Further characterization of plant biomass showed presence of both acidic and basic surface functionalities that might facilitate binding of metal ions. Fourier transform infrared (FTIR) spectra of plant biomass suggested involvement of carbonyl (C=O), carboxyl (-COO), and hydroxyl (-OH) groups in binding heavy metals to plant biomass. The studies establish S. natans as an effective biosorbent for removing heavy metals from wastewater and further emphasize biomass utilization in wastewater treatment technologies.

Dhir B; Nasim SA; Sharmila P; Saradhi PP

2010-02-01

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Removal of Heavy Metals from Textile Wastewater using Zeolite  

Directory of Open Access Journals (Sweden)

Full Text Available Heavy metals such as lead (Pb), chromium (Cr), cadmium (Cd) and copper (Cu) are widely used for production of colour pigments of textile dyes. Textile dyes pollutants are being released to the environment at various stages of operation therefore it is necessary that the pollutants are treated before discharge using zeolite with and without alum. A study was carried out to compare the effectiveness of treatment using zeolite with and without alum for the removal of heavy metals (Pb, Cu, Cd, Cr) in textile effluent. The concentrations of these heavy metals in the textile wastewater samples were reduced to more than 50 percent after treating with zeolite. The sequence in increasing order of removal efficiency of these heavy metals using zeolite was Cd < Pb < Cr < Cu. When the textile wastewater sample was treated using zeolite and 10 mg/L of alum, 80% of the heavy metals (Cd and Cu) were removed. The most effective treatment prior to removal of heavy metals from textile wastewater sample is by using zeolite with the addition of 10 mg/L of alum as flocculants.

Normala Halimoon

2010-01-01

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Process for removing heavy metal ions from aqueous fluids  

Energy Technology Data Exchange (ETDEWEB)

The invention relates to an improved method for removing corrosive heavy metal ions from aqueous fluids used in heat exchange systems. The method provides for the employment of a getter upstream of a heat exchange and in proximate contact therewith so that the getter removes said ions from said fluid before the fluid is introduced into the heat exchanger.

Popplewell, J.M.

1980-01-08

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Heavy metal removal by biosorption using Phanerochaete chrysosporium.  

UK PubMed Central (United Kingdom)

Biosorption using microbial cells as adsorbents is being seen as a cost-effective method for the removal of heavy metals from wastewaters. Biosorption studies with Phanerochaete chrysosporium were performed for copper (II), lead (II), and cadmium (II) to evaluate the effectiveness and to optimize the operational parameters using response surface methodology. The operational parameters chosen were initial metal ion concentration, pH, and biosorbent dosage. Using this method, the metal removal could be correlated to the operational parameters, and their values were optimized. The results showed fairly high adsorptive capacities for all the metals within the settings of the operational parameters. The removal efficiencies followed the order Pb > Cu > Cd. As a general trend, metal removal efficiency decreased as the initial metal ion concentration increased, and the results fitted the Langmuir and Freundlich isotherms well.

Gopal M; Pakshirajan K; Swaminathan T

2002-07-01

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BIOSORPTIVE REMOVAL OF HEAVY METALS FROM WASTEWATER USING DUCKWEED  

Directory of Open Access Journals (Sweden)

Full Text Available Water pollution has been recognized as a problem for decades. The use of heavy metals in industries and their regular mining increases their concentration in water bodies. Unlike organic compounds, metals cannot degrade, and therefore effective cleanup requires their immobilization to reduce or remove toxicity. A few conventional methods employed to remove heavy metals from wastewater are expensive, require skilled labors and maintenance. Therefore, the use of aquatic plants has come up since the last few decades. Duckweed is onesuch plant employed as a biosorbent and has been considered a better alternative than any other aquatic plant because of high tolerance to cold than water hyacinth, more easilyharvested than algae, capable of rapid growth (0.1 to 0.5 g g-1 day-1) and small size of plant. This study aims to determine the suitability of this plant for biosorbing toxic heavy metalscommonly found in industrial wastewater, domestic wastewater, and seepage water.

Ankita Suhag; Richa Gupta; Archana Tiwari

2011-01-01

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Heavy metals removal from dredged sediments using electro kinetics  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This study focuses on the use of a remediation process to remove particle-bound recalcitrant pollutants (heavy metals) from dredged harbor sediments which must be previously treated before reuse in civil engineering. Electrokinetic (EK) remediation is generally accepted as one of the most suitable ...

Ammami M. T.; Benamar A.; Koltalo F.; Wang H. Q.; LeDerf F.

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Removal of Heavy Metal from Aqueous Solution by Aspergillus sp  

UK PubMed Central (United Kingdom)

The biomas of Aspergillus so jae M146 and Aspergillus oryzae M149 is an effective agent for heavy metal removal. The effects of pH, temperature, equilibration time and pre-treatment reagents on the removel of Pb (III),Cd(II)from aqueous solutions by Aspergillus sojae M146 and Aspergillus oryzae M149 have been studied. The optimal conditions for both heavy metal removal were pH 5.5, equilibration temperature 30 ? and equilibration time 1 hour with 69.76% Pb(II) and 72.28% Cd(II) being removed by Aspergillus so jae M146 and 60.64% Pb(II) and 81.34% Cd(II) by Aspergillus orgzae M149. Chemical treatment of cultivated fungal biomass (0.1 mol/L NaOH, 0.1 mol/L HCl, 30% ethanol and distilled water) affected the efficiency of metal removal by Aspergillus so jae M146 and Aspergillus oryzae M149. Pretreatment of biomss by NaOH enhanced Cd(II) and Pb(II) removal, while pretreatment by HCl, ethanol and distilled water reduced Cd(II) and Pb(II) removal. Once heavy metals were accumulated in the fungal biomass, the release back to the aqueous solutions was efficient (>80%) when the loaded-biomass was treated with 0.1mol/L Na_2CO_3 or 0.1mol/L EDTA indicating the potential for regeneration and reuse of the microbial biomass for further heavy metal removal.

Huang Minsheng; Shi Huali; Zheng Leping

2002-01-01

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Removing heavy metals by in vitro cultures.  

UK PubMed Central (United Kingdom)

In vitro roots cultures of Typha latifolia and Scirpus americanus aquatic plants have the capacity to remove Pb (II), Mn (II), and Cr (III) from the culture medium. Both species remove Cr and Pb by an absorption process, while Mn is mainly adsorbed to the root surface. This chapter describes a protocol for the establishment of in vitro roots cultures (nontransformed) from T. latifolia and S. americanus, and the procedure for the uptake analysis of Pb (II), Mn (II), and Cr (III) by roots.

Santos-Díaz Mdel S; Barrón-Cruz Mdel C

2012-01-01

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Chitosan removes toxic heavy metal ions from cigarette mainstream smoke  

Science.gov (United States)

This study investigated the removal of heavy metal ions from cigarette mainstream smoke using chitosan. Chitosan of various deacetylation degrees and molecular weights were manually added to cigarette filters in different dosages. The mainstream smoke particulate matter was collected by a Cambridge filter pad, digested by a microwave digestor, and then analyzed for contents of heavy metal ions, including As(III/V), Pb(II), Cd(II), Cr(III/VI) and Ni(II), by graphite furnace atomic absorption spectrometry (GFAAS). The results showed that chitosan had a removal effect on Pb(II), Cd(II), Cr(III/VI) and Ni(II). Of these, the percent removal of Ni(II) was elevated with an increasing dosage of chitosan. Chitosan of a high deace tylation degree exhibited good binding performance toward Cd(II), Cr(III/VI) and Ni(II), though with poor efficiency for Pb(II). Except As(III/V), all the tested metal ions showed similar tendencies in the growing contents with an increasing chitosan molecular weight. Nonetheless, the percent removal of Cr(III/VI) peaked with a chitosan molecular weight of 200 kDa, followed by a dramatic decrease with an increasing chitosan molecular weight. Generally, chitosan had different removal effects on four out of five tested metal ions, and the percent removal of Cd(II), Pb(II), Cr(III/VI) and Ni(II) was approximately 55%, 45%, 50%, and 16%, respectively. In a word, chitosan used in cigarette filter can remove toxic heavy metal ions in the mainstream smoke, improve cigarette safety, and reduce the harm to smokers.

Zhou, Wen; Xu, Ying; Wang, Dongfeng; Zhou, Shilu

2013-09-01

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Removal of heavy metals ions by synthetic carbonate apatite  

International Nuclear Information System (INIS)

The removal of cations such as Zn2+, Cd2+ and Pb2+ in aqueous solutions containing various counter-anions by synthetic carbonate apatite (CAP) has been in investigated using batch methods. The ranking of ions according to amount exchanged was as follows: Pb2+ > Cd2+ > Zn2+. The reaction with Pb2'+ ions was especially remarkable: after 2 hours, removal of Pb2+ ions from the 1000 ppm solution was 98,1%. XRD and IR analysis indicated the formation of a single phase of Pb'2+ ion-exchanged carbonate apatite. we can conclude that synthesized CAP is useful in removing heavy-metal ions from water. (author)

1999-01-01

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Heavy metal removal from water solutions  

Directory of Open Access Journals (Sweden)

Full Text Available Equilibrium and kinetic data for copper adsorption on chitosan and Lewatit S100 in batch systems have been obtained. For chitosan particles the best fit isotherm in the concentration range 0 – 8 g.m-3 is the R-P isotherm and for Lewatit S100-G the best fit isotherm in the concentration range 0 – 8 g.m-3 is the Langmuir isotherm. The maximum capacity of chitosan is slightly higher than that of Lewatit; however at aqueous concentrations below about 150 g.m-3 the amount of metal adsorbed on Lewatit is higher.

Tomáš Bakalár; Milan Búgel; Štefan Schlosser; Barbora Onderková

2005-01-01

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Electrodialytic Removal of Heavy Metals from Different Solid Waste Products  

DEFF Research Database (Denmark)

A variety of heavy metal polluted waste products must be handled today. Electrochemical methods have been developed for remediation of polluted soil. One of the methods is the electrodialytic remediation method that is based on electromigration of heavy metal ions and ionic species within the soil matrix, and a separation of the soil and the process solutions, where the heavy metals are concentrated, with ion exchange membranes. For remediation of some soils, such as calcareous soils, it is necessary to add an enhancement solution. It was shown in a laboratory experiment that ammonium citrate could be used when removing Cu and Cr from a soil with 25% carbonates. The final concentrations of the elements were below the target values after the remediation. A question of whether the electrodialytic remediation method can be used for other waste products arose. Preliminary experiments showed that the method could be used for removal of different heavy metals from impregnated wood waste, fly ash from straw combustion, and fly ash from municipal solid waste incineration. The best result was obtained with the wood waste where more than 80% of each of the polluting elements Cu, Cr and As was removed in a 7-day experiment in which oxalic acid was used as enhancement solution. From the straw ash, 66% of the Cd was removed, but 64% of the fly ash dry mass dissolved during the treatment. In this actual experiment, no enhancement solution was used but that will be necessary to avoid dissolution of the ash to such a high extent. For the fly ash from waste incineration, ammonium citrate was tested as enhancement solution and in 14 days 62% Cd, 53% Cu, 6% Pb, and 31% Zn were removed. The preliminary results were thus promising for developing the electrodialytic method to other products than soil, although more research is needed especially in finding the best enhancement solutions for each product.

Ottosen, Lisbeth M.; Christensen, Iben Vernegren

2003-01-01

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Removal of metals from heavy oils with phosphorus - Alumina catalysts  

Energy Technology Data Exchange (ETDEWEB)

Earlier it was found that various oil-soluble phosphorous compounds were active for vanadium removal from different crude oils. The phosphorous compounds preferentially reacted with low molecular weight vanadium species in the resin fraction and therefore the highest rate of vanadium removal was observed when the asphaltene fraction was partially or completely removed. Phosphorous compounds promoted the rate of vanadium removal during hydroprocessing over alumina in a trickle bed reactor. Some metal phosphates were prepared and tested for demetallization activity. Several mixed metal phosphates, such as Cr-Zr, Ni-Zr, Cu-Zr, V-Co-Zr, Fe-Co-Zr, Ni-Co-Zr, etc., exhibited high activity for both vanadium and nickel removal. These catalysts were found to possess HDM activity and activity maintenance comparable to conventional hydrotreating catalysts available commercially. The vanadium removal selectivity of the mixed metal phosphates was similar to that of the commercial catalyst, but much lower than that observed earlier for oil soluble phosphorous compounds. Since the lack of high vanadium selectivity for the mixed metal phosphates could be due to their transition metal component, they investigated the hydroprocessing of heavy oils over aluminas impregnated with different inorganic phosphorous compounds.

Kukes, S.G.; Parrott, S.L.; Gardner, L.E. (Phillips Petroleum Co., Bartlesville, OK (USA))

1987-04-01

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Bacteria immobilisation on hydroxyapatite surface for heavy metals removal.  

Science.gov (United States)

Selected bacterial strains were immobilised on the surface of hydroxyapatite (Ca10(PO4)6(OH)2 - HAp) of natural origin (fish bones). The capacity of the material, alone and in combination with the bacterial strains to act as heavy metal removers from aqueous streams was assessed. Pseudomonas fluorescens (S3X), Microbacterium oxydans (EC29) and Cupriavidus sp. (1C2) were chosen based on their resistance to heavy metals and capacity of adsorbing the metals. These systems were tested using solutions of Zn(II), Cd(II) and in solutions containing both metals. A synergistic effect between the strains and HAp, which is effective in removing the target heavy metals on its own, was observed, as the combination of HAp with the bacterial strains led to higher adsorption capacity for both elements. For the solutions containing only one metal the synergistic effect was greater for higher metal concentrations; 1C2 and EC29 were the most effective strains for Zn(II) and Cd(II) respectively, while S3X was less effective. Overall, an almost four-fold increase was observed for the maximum adsorption capacity for Zn(II) when 1C2 was employed - 0.433 mmol/g in comparison of 0.121 mmol/g for the unmodified HAp. For Cd(II), on the other hand, an almost three-fold increase was registered with EC29 bacterial strain - 0.090 vs 0.036 mmol/g for the unmodified HAp. When the solutions containing both metals were tested, the effect was more marked for lower concentrations. PMID:23524400

Piccirillo, C; Pereira, S I A; Marques, A P G C; Pullar, R C; Tobaldi, D M; Pintado, M E; Castro, P M L

2013-03-20

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Removal of heavy metals from electroplating wastewater by membrane  

Directory of Open Access Journals (Sweden)

Full Text Available This research was to study the treatment of heavy metals in electroplating wastewater using membranes. Two selected membrane types, cellulose acetate microfiltration membrane with pore size 0.2 ?m and polysulfone ultrafiltration membrane with MWCO of 30 kDa were used in this study. Synthetic and factory electroplating wastewater were used as the samples. The experiments were performed by chemical precipitating both synthetic and factory wastewater in the first step and membrane filtrating of supernatant at the pressure of 50, 100 and 200 kPa in the second step. The concentration of chromium, copper, nickel and zinc of treated water were compared with standard values given by the Ministry of Industry (MOI), Thailand. The experimental results showed that flux was highest at the pressure of 200 kPa and decreased as the pressure decreased. The rejection was highest at the pressure of 50 kPa and decreased as pressure increased. The results from synthetic wastewater were better than those from factory wastewater. Thecapability of heavy metal removal of microfiltration and ultrafiltration membrane was the same, but microfiltration gave more flux. The heavy metal removal efficiency of microfiltration of synthetic electroplating wastewater of four processes of chromium, copper, nickel and zinc electroplating , each was higher than that from factory wastewater but slightly lower than the removal efficiency obtained from composite synthetic wastewater. The removal efficiency of chromium, copper, nickel and zinc from composite synthetic wastewater was higher than those from composite factory wastewater for both microfiltration and ultrafiltration processes. The results from the study of membrane surface washing showed little flux increase after washing the membrane by stirring with a propeller at a distance of 2 mm above membrane surface at 400 rpm for 30 minutes.

Galaya Srisuwan; Poonpetch Thongchai

2002-01-01

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Crab shell for the removal of heavy metals from aqueous solution.  

UK PubMed Central (United Kingdom)

The ability of crab shell to remove heavy metals from aqueous solution was evaluated by comparing with that of several sorbents (cation exchange resin, zeolite, granular activated carbon, powdered activated carbon). All experiments were conducted using several heavy metal ion solutions (Pb, Cd, Cu, Cr). The orders of heavy metal removal capacity and initial heavy metal removal rate were found as crab shell > cation exchange resin > zeolite > powdered activated carbon>granular activated carbon. Therefore, crab shell is satisfactory as a good biosorbent for the heavy metal removal. The study indicates that the removal of these heavy metals is selective, with Pb and Cr being removed in preference to Cd and Cu. The sorption equilibrium of heavy metal ions on sorbents was modeled on the applications of Langmuir and Freundlich.

An HK; Park BY; Kim DS

2001-10-01

 
 
 
 
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Industrial effluent treatments using heavy-metal removing bacterial bioflocculants  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english Bioflocculants produced by Herbaspirillium sp. CH7, Paenibacillus sp. CH11, Bacillus sp. CH15 and a Halomonas sp. were preliminarily evaluated as flocculating agents in the treatment of industrial wastewater effluents. Industrial (1 local chemical-industry and 2 textile-industry: Biavin 109-medium blue dye and Whale dye) effluent (9 m?) containing various heavy metals was vortexed with 1 m? of bioflocculant in a 25 m? test tube. One m? of water (Mi (more) llipore Elix purification system, 17 mega?) was substituted for the bioflocculant in the control. After 5 min, the heavy metal concentrations, the microbial population and the turbidity of the top layer of the industrial effluent were determined using ICP-OES, spread-plate technique and a turbidity meter respectively. The flocculating activity was calculated based on absorbance at a wavelength of 550 nm. Bioflocculants produced in this study were capable of removing several heavy metals from industrial effluents simultaneously and effectively. This was significant (p

Lin, J; Harichund, C

2011-04-01

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Heavy metal removal from aqueous solutions by activated phosphate rock  

International Nuclear Information System (INIS)

[en] The use of natural adsorbent such as phosphate rock to replace expensive imported synthetic adsorbent is particularly appropriate for developing countries such as Tunisia. In this study, the removal characteristics of lead, cadmium, copper and zinc ions from aqueous solution by activated phosphate rock were investigated under various operating variables like contact time, solution pH, initial metal concentration and temperature. The kinetic and the sorption process of these metal ions were compared for phosphate rock (PR) and activated phosphate rock (APR). To accomplish this objective we have: (a) characterized both (PR) and (APR) using different techniques (XRD, IR) and analyses (EDAX, BET-N2); and, (b) qualified and quantified the interaction of Pb2+, Cd2+, Cu2+ and Zn2+ with these sorbents through batch experiments. Initial uptake of these metal ions increases with time up to 1 h for (PR) and 2 h for (APR), after then, it reaches equilibrium. The maximum sorption obtained for (PR) and (APR) is between pH 2 and 3 for Pb2+ and 4 and 6 for Cd2+, Cu2+ and Zn2+. The effect of temperature has been carried out at 10, 20 and 40 deg. C. The data obtained from sorption isotherms of metal ions at different temperatures fit to linear form of Langmuir sorption equation. The heat of sorption (?Ho), free energy (?Go) and change in entropy (?So) were calculated. They show that sorption of Pb2+, Cd2+, Cu2+ and Zn2+on (PR) and (APR) an endothermic process. These findings are significant for future using of (APR) for the removal of heavy metal ions from wastewater under realistic competitive conditions in terms of initial heavy metals, concentrations and pH

2008-08-15

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Removal of heavy metals from the environment by biosorption  

Energy Technology Data Exchange (ETDEWEB)

The pollution of the environment with toxic metals is a result of many human activities, such as mining and metallurgy, and the effects of these metals on the ecosystems are of large economic and public-healthsignificance. This paper presents the features and advantages of the unconventional removal method of heavy metals - biosorption - as a part of bioremediation. Bioremediation consists of a group of applications, which involve the detoxification of hazardous substances instead of transferring them from one medium to another, by means of microbes and plants. This process is characterized as less disruptive and can be often carried out on site, eliminating the need to transport the toxic materials to treatment sites. The biosorption (sorption of metallic ions from solutions by live or dried biomass) offers an alternative to the remediation of industrial effluents as well as the recovery of metals contained in other media. Biosorbents are prepared from naturally abundant and/or waste biomass. Due to the high uptake capacity and very cost-effective source of the raw material, biosorption is a progression towards a perspective method. The mechanism by which microorganisms take up metals is relatively unclear, but it has been demonstrated that both living and non-living biomass may be utilized in biosorptive processes, as they often exhibit a marked tolerance towards metals and other adverse conditions. One of their major advantages is the treatment of large volumes of effluents with low concentrations of pollutants. Models developed were presented to determine both the number of adsorption sites required to bind each metal ion and the rate of adsorption, using a batch reactor mass balance and the Langmuir theory of adsorption to surfaces or continuous dynamic systems. Two main categories of bioreactors used in bioremediation - suspended growth and fixed film bioreactors - are discussed. Reactors with varying configurations to meet the different requirements for biosorption are analyzed considering two major groups of reactors - batch reactors and continuous reactors. Biosorption is treated as an emerging technology effective in removing even very low levels of heavy metal. (Abstract Copyright [2004], Wiley Periodicals, Inc.)

Gavrilescu, M. [Technical University of Iasi, Faculty of Industrial Chemistry, Department of Environmental Engineering, Mangeron Blvd. 71, 6600-Iasi (Romania)

2004-06-01

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BIOSORPTIVE REMOVAL OF HEAVY METALS FROM WASTEWATER USING DUCKWEED  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Water pollution has been recognized as a problem for decades. The use of heavy metals in industries and their regular mining increases their concentration in water bodies. Unlike organic compounds, metals cannot degrade, and therefore effective cleanup requires their immobilization to reduce or remo...

Ankita Suhag; Richa Gupta; Archana Tiwari

25

Comparison of electrocoagulation and chemical coagulation for heavy metal removal  

Energy Technology Data Exchange (ETDEWEB)

Copper (Cu), chromium (Cr), and nickel (Ni) removal from metal plating wastewater by electrocoagulation and chemical coagulation was investigated. Chemical coagulation was performed using either aluminum sulfate or ferric chloride, whereas electrocoagulation was done in an electrolytic cell using aluminum or iron electrodes. By chemical coagulation, Cu-, Cr-, and Ni-removal of 99.9 % was achieved with aluminum sulfate and ferric chloride dosages of 500, 1000, and 2000 mg L{sup -1}, respectively. Removal of metals by electrocoagulation was affected by the electrode material, wastewater pH, current density, number of electrodes, and electrocoagulation time. Electrocoagulation with iron electrodes at a current density of 10 mA cm{sup -2}, electrocoagulation time of 20 min, and pH 3.0 resulted in 99.9 % Cu-, 99.9 % Cr-, and 98 % Ni-removal. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

Akbal, F.; Camci, S. [Ondokuz Mayis University, Engineering Faculty, Environmental Engineering Department, Kurupelit, Samsun (Turkey)

2010-10-15

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Using biopolymers to remove heavy metals from soil and water  

Energy Technology Data Exchange (ETDEWEB)

Chemical remediation of soil may involve the use of harsh chemicals that generate waste streams, which may adversely affect the soil's integrity and ability to support vegetation. This article reviews the potential use of benign reagents, such as biopolymers, to extract heavy metals. The biopolymers discussed are chitin and chitosan, modified starch, cellulose, and polymer-containing algae. (Copyright (c) Remediation 1994.)

Krishnamurthy, S.; Frederick, R.M.

1993-11-19

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Cyclic electrowinning/precipitation (CEP) system for the removal of heavy metal mixtures from aqueous solutions.  

Science.gov (United States)

The description and operation of a novel cyclic electrowinning/precipitation (CEP) system for the simultaneous removal of mixtures of heavy metals from aqueous solutions are presented. CEP combines the advantages of electrowinning in a spouted particulate electrode (SPE) with that of chemical precipitation and redissolution, to remove heavy metals at low concentrations as solid metal deposits on particulate cathode particles without exporting toxic metal precipitate sludges from the process. The overall result is very large volume reduction of the heavy metal contaminants as a solid metal deposit on particles that can either be safely discarded as such, or further processed to recover particular metals. The performance of this system is demonstrated with data on the removal of mixtures of copper, nickel, and cadmium from aqueous solutions. PMID:22102792

Grimshaw, Pengpeng; Calo, Joseph M; Hradil, George

2011-11-15

28

Cyclic electrowinning/precipitation (CEP) system for the removal of heavy metal mixtures from aqueous solutions.  

UK PubMed Central (United Kingdom)

The description and operation of a novel cyclic electrowinning/precipitation (CEP) system for the simultaneous removal of mixtures of heavy metals from aqueous solutions are presented. CEP combines the advantages of electrowinning in a spouted particulate electrode (SPE) with that of chemical precipitation and redissolution, to remove heavy metals at low concentrations as solid metal deposits on particulate cathode particles without exporting toxic metal precipitate sludges from the process. The overall result is very large volume reduction of the heavy metal contaminants as a solid metal deposit on particles that can either be safely discarded as such, or further processed to recover particular metals. The performance of this system is demonstrated with data on the removal of mixtures of copper, nickel, and cadmium from aqueous solutions.

Grimshaw P; Calo JM; Hradil G

2011-11-01

29

Aminopolycarboxylic acid functionalized adsorbents for heavy metals removal from water.  

UK PubMed Central (United Kingdom)

Due to the excellent chelating properties of aminopolycarboxylic acid (APCAs), they can be used for the removal of metals from contaminated waters. This paper reviews the research results obtained for both commercial and self-prepared adsorbents functionalized with four most common APCAs: iminodiacetic acid (IDA), nitrilotriacetic acid (NTA), ethylenediaminetetraacetic acid (EDTA), and diethylenetriaminepentaacetic acid (DTPA). The structural characteristics and unique metal binding properties of these chelating adsorbents are presented. The theory of the adsorption phenomena is discussed based on the kinetics of adsorption, equilibrium adsorption isotherm models, and thermodynamic models. The most important applications of APCA-functionalized adsorbents are also described. APCA-functionalized adsorbents are found to be highly promising materials for metal removal from contaminated waters.

Repo E; Warcho? JK; Bhatnagar A; Mudhoo A; Sillanpää M

2013-09-01

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Remoção de metais pesados de efluentes industriais por aluminossilicatos Removal of heavy metals from wastewaters by aluminosilicate  

Directory of Open Access Journals (Sweden)

Full Text Available This review had as aim the bibliography research for the use of aluminosilicates to remove heavy metals from wastewaters. Advanced studies based on parameters that have influence for removal of heavy metals as pH, metal concentration, effect of ligants and removal capacity of zeolites and clays, were reported. These studies demonstrate that aluminosilicates can be successfully used for the removal of heavy metals under the optimized conditions.

Mônica Regina Marques Palermo de Aguiar; Amanda Cardoso Novaes; Alcides Wagner Serpa Guarino

2002-01-01

31

Remoção de metais pesados de efluentes industriais por aluminossilicatos/ Removal of heavy metals from wastewaters by aluminosilicate  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english This review had as aim the bibliography research for the use of aluminosilicates to remove heavy metals from wastewaters. Advanced studies based on parameters that have influence for removal of heavy metals as pH, metal concentration, effect of ligants and removal capacity of zeolites and clays, were reported. These studies demonstrate that aluminosilicates can be successfully used for the removal of heavy metals under the optimized conditions.

Aguiar, Mônica Regina Marques Palermo de; Novaes, Amanda Cardoso; Guarino, Alcides Wagner Serpa

2002-12-01

32

Sorption studies on heavy metal removal using chitin/bentonite biocomposite.  

Science.gov (United States)

Contamination of water by toxic heavy metals due to urbanization is a world-wide environmental problem, which changes chemical and biological properties of both surface and ground water. The heavy metals render the water unsuitable for drinking and are also highly toxic to human beings. Removal of heavy metals is therefore essential. Thus, in my present work batch adsorption studies have been used to remove the Cr(VI) from aqueous solution using chitin composite. The data obtained from batch method at optimized conditions have been subjected to Freundlich and Langmuir isotherm studies. The data were suitable for both models indicating favorability. PMID:23148945

Saravanan, D; Gomathi, T; Sudha, P N

2012-11-10

33

Sorption studies on heavy metal removal using chitin/bentonite biocomposite.  

UK PubMed Central (United Kingdom)

Contamination of water by toxic heavy metals due to urbanization is a world-wide environmental problem, which changes chemical and biological properties of both surface and ground water. The heavy metals render the water unsuitable for drinking and are also highly toxic to human beings. Removal of heavy metals is therefore essential. Thus, in my present work batch adsorption studies have been used to remove the Cr(VI) from aqueous solution using chitin composite. The data obtained from batch method at optimized conditions have been subjected to Freundlich and Langmuir isotherm studies. The data were suitable for both models indicating favorability.

Saravanan D; Gomathi T; Sudha PN

2013-02-01

34

Dietary Supplement For Promoting Removal Of Heavy Metals From The Body  

UK PubMed Central (United Kingdom)

A dietary supplement for removing or preventing the bio-accumulation of heavy metals in the body includes one or more chelators, precursors therefore, with at least one chelator capable of crossing the blood brain barrier to promote capture of a heavy metal ion from a site in the central nervous system, and a vascular system promoter for assisting in distributing the chelators within the body. The chelator then crosses back through the blood brain barrier with the entrained heavy metal ion. Preferably, one or more secondary chelators promotes binding any of the heavy metal released from the primary chelator and hold it for removal via an excretion pathway. In one embodiment, the supplement includes a cilantro extract to assist the body's' natural defense systems in removing mercury from the human body.; Using the dietary supplement limits the accumulation of heavy metals in the body, which are encountered in trace amounts from various environmental sources, promotes removal of heavy metals previously accumulated in the body and thereby alleviates the symptoms and conditions associated with heavy metal toxicity.

COLEMAN HENRY D; SUDOL R. NEIL; SAPONE WILLIAM J

35

Removal of heavy metals from water effluents using supermacroporous metal chelating cryogels.  

Science.gov (United States)

Applications of IDA in, for example, immobilized metal ion affinity chromatography for purification of His-tagged proteins are well recognized. The use of IDA as an efficient chelating adsorbent for environmental separations, that is, for the capture of heavy metals, is not studied. Adsorbents based on supermacroporous gels (cryogels) bearing metal chelating functionalities (IDA residues and ligand derived from derivatization of epoxy-cryogel with tris(2-aminoethyl)amine followed by the treatment with bromoacetic acid (defined as TBA ligand)) have been prepared and evaluated on capture of heavy metal ions. The cryogels were prepared in plastic carriers, resulting in desired mechanical stability and named as macroporous gel particles (MGPs). Sorption and desorption experiments for different metals (Cu²+, Zn²+, Cd²+, and Ni²+ with IDA adsorbent and Cu²+ and Zn²+ with TBA adsorbent) were carried out in batch and monolithic modes, respectively. Obtained capacities with Cu²+ were 74 ?mol/mL (TBA) and 19 ?mol/mL gel (IDA). The metal removal was higher for pH values between pH 3 and 5. Both adsorbents showed improved sorption at lower temperatures (10°C) than at higher (40°C) and the adsorption significantly dropped for the TBA adsorbent and Zn²+ at 40°C. Desorption of Cu²+ by using 1 M HCl and 0.1 M EDTA was successful for the IDA adsorbent whereas the desorption with the TBA adsorbent needs further attention. The result of this work has demonstrated that MGPs are potential treatment alternatives within the field of environmental separations and the removal of heavy metals from water effluents. PMID:20945486

Onnby, Linda; Giorgi, Camilla; Plieva, Fatima M; Mattiasson, Bo

36

Removal of heavy metals from water effluents using supermacroporous metal chelating cryogels.  

UK PubMed Central (United Kingdom)

Applications of IDA in, for example, immobilized metal ion affinity chromatography for purification of His-tagged proteins are well recognized. The use of IDA as an efficient chelating adsorbent for environmental separations, that is, for the capture of heavy metals, is not studied. Adsorbents based on supermacroporous gels (cryogels) bearing metal chelating functionalities (IDA residues and ligand derived from derivatization of epoxy-cryogel with tris(2-aminoethyl)amine followed by the treatment with bromoacetic acid (defined as TBA ligand)) have been prepared and evaluated on capture of heavy metal ions. The cryogels were prepared in plastic carriers, resulting in desired mechanical stability and named as macroporous gel particles (MGPs). Sorption and desorption experiments for different metals (Cu²+, Zn²+, Cd²+, and Ni²+ with IDA adsorbent and Cu²+ and Zn²+ with TBA adsorbent) were carried out in batch and monolithic modes, respectively. Obtained capacities with Cu²+ were 74 ?mol/mL (TBA) and 19 ?mol/mL gel (IDA). The metal removal was higher for pH values between pH 3 and 5. Both adsorbents showed improved sorption at lower temperatures (10°C) than at higher (40°C) and the adsorption significantly dropped for the TBA adsorbent and Zn²+ at 40°C. Desorption of Cu²+ by using 1 M HCl and 0.1 M EDTA was successful for the IDA adsorbent whereas the desorption with the TBA adsorbent needs further attention. The result of this work has demonstrated that MGPs are potential treatment alternatives within the field of environmental separations and the removal of heavy metals from water effluents.

Onnby L; Giorgi C; Plieva FM; Mattiasson B

2010-09-01

37

Investigation of heavy metal removal from motorway stormwater using inorganic ion exchange  

International Nuclear Information System (INIS)

[en] Stormwater runoff from motorway surfaces contains toxic heavy metals that are not sufficiently removed by current treatment systems. This research has investigated the potential use of inorganic ion exchange materials to further reduce the levels of dissolved heavy metals. Candidate materials (synthetic/natural zeolites, clay/modified clay, hydrotalcite, lignite) were tested by a shaking procedure (mixed 5 mg dm-3 of each heavy metals, shaken for 10 min) and analysed by atomic absorption spectrometry. The synthetic zeolites MAP and Y showed 100% heavy metal removal and were investigated further by a series of batch experiments. The zeolites exhibited a selectivity sequence Pb > Cu > Cd ? Zn. Zeolite MAP has a high capacity for heavy metal uptake (4.5 meq g-1), but is not practical for use in a treatment facility owing to its low particle size (3 ?m). However, large zeolite pellets (? 2 mm) were found to have a low heavy metal uptake (? 44 %) due to diffusion limitations. Selected materials (zeolites MAP, Y, mordenite, and carbon-based lignite) were tested in actual and spiked motorway stormwater. The synthetic zeolites effectively remove heavy metals (? 100 %) but change the environmental chemistry of the stormwater by releasing high concentrations of sodium, removing calcium ions and increasing the solution pH. The presence of other dissolved contaminants in motorway stormwater inhibited the uptake of heavy metals by the natural zeolite mordenite (34 % less removal). Alkali/alkaline-earth metals (Na, Ca) in solution compete for exchange sites in lignite and mordenite, reducing the heavy metal uptake. Chloride in solution forms complexes with cadmium, severely reducing its uptake by zeolite Y. The presence of dissolved road salt is a potentially serious concern as it causes previously exchanged heavy metals to be re-eluted, especially zinc and cadmium. Zeolite MAP as an exchanger is relatively unaffected by road salt. There is potential for the use of ion exchange materials to remove heavy metals from motorway stormwater, but a balance needs to be achieved between a practical particle size, capacity for heavy metal uptake and the potential environmental impact. (author)

2002-01-01

38

Utilization of Carbamoyethylated Cotton for Heavy Metal Ion Removal  

Directory of Open Access Journals (Sweden)

Full Text Available Cotton cellulose in fabric form was rendered ion exchanger via Carbamoyethylation Reaction (CER). The latter was carried out using acrylamide (Aam) and sodium hydroxide. The resulted carbamoyethylated cotton having amide functional groups (CONH2) was monitored for its ability to adsorb heavy metals from their aqueous solutions. Different factors affecting adsorption of metal ions onto the latter substrate such as metal ion concentration, pH, treatment time and temperature were studied systematically. Results obtained reflect the following findings: (a) the adsorption value increases by increasing the metal ion concentration up to 60 m mol L-1 then levels off, (b) the carbamoylethylated cotton was found to be selective adsorbent for Hg2+ at pH 0.5, (c) the adsorption values is higher at 40 °C then levels off by raising the temperature to 60 and 80 °C, respectively, (d). The adsorption values increase by increasing the treatment time up to 5 h at 40 and 60 °C and 3 h at 80 °C then levels off and (e) The adsorption values of the aforementioned substrate in question at different metal ions follow the order: Hg2+ > Cu2+ > Zn2+ > Co2+ > Pb2+.

Kh.M. Mostafa; Hassan Al-Bar

2005-01-01

39

Removal of heavy metals by two free floating aquatic macrophytes.  

UK PubMed Central (United Kingdom)

A concentration-dependent decrease in biomass, protein, RNA, DNA, and nutrient (NO3(-) and PO4(3-)) uptake of Lemna minor and Azolla pinnata by Cr, Ni, and Zn was detected. Cr was found to exert maximum toxicity followed by Ni and Zn. Metal uptake was dependent on time and concentration of metal in the external medium. Both the macrophytes, however, showed preference for Zn followed by Ni and Cr. The uptake kinetics also revealed a low Vmax and high Km for Cr. L. minor was more efficient in accumulating Zn and Cr than A. pinnata in Ni. Compared to immobilized algae and bacterial capsules the test macrophytes showed a greater efficiency for metal removal.

Mallick N; Shardendu; Rai LC

1996-12-01

40

Heavy metal removal from sewage sludge ash by thermochemical treatment with gaseous hydrochloric acid.  

UK PubMed Central (United Kingdom)

Sewage sludge ash (SSA) is a suitable raw material for fertilizers due to its high phosphorus (P) content. However, heavy metals must be removed before agricultural application and P should be transferred into a bioavailable form. The utilization of gaseous hydrochloric acid for thermochemical heavy metal removal from SSA at approximately 1000 °C was investigated and compared to the utilization of alkaline earth metal chlorides. The heavy metal removal efficiency increased as expected with higher gas concentration, longer retention time and higher temperature. Equivalent heavy metal removal efficiency were achieved with these different Cl-donors under comparable conditions (150 g Cl/kg SSA, 1000 °C). In contrast, the bioavailability of the P-bearing compounds present in the SSA after thermal treatment with gaseous HCl was not as good as the bioavailability of the P-bearing compounds formed by the utilization of magnesium chloride. This disadvantage was overcome by mixing MgCO(3) as an Mg-donor to the SSA before thermochemical treatment with the gaseous Cl-donor. A test series under systematic variation of the operational parameters showed that copper removal is more depending on the retention time than the removal of zinc. Zn-removal was declined by a decreasing ratio of the partial pressures of ZnCl(2) and water.

Vogel C; Adam C

2011-09-01

 
 
 
 
41

Ion exchange system design for removal of heavy metals from acid mine drainage wastewater  

Directory of Open Access Journals (Sweden)

Full Text Available This paper discusses the methodology used to determine the optimal ion-exchange column size to process all separate batchesof feeds from acid mine drainage wastewater.The optimal design ensures the best utilization of resin material and therefore results in a minimum amount of spent resins.Ion exchanger materials have been studied for removing heavy metals from a metal bearing wastes. For the current treatment,a facility has been designed for the removal of heavy metals from the acid mine drainage (AMD) waste by the ion-exchange technology.

R. W. Gaikwad; V. S. Sapkal; R. S. Sapkal

2010-01-01

42

Silica coated magnetite nanoparticles for removal of heavy metal ions from polluted waters  

CERN Multimedia

Magnetic removal of Hg2+ and other heavy metal ions like Cd2+, Pb2+ etc. using silica coated magnetite particles from polluted waters is a current topic of active research to provide efficient water recycling and long term high quality water. The technique used to study the bonding characteristics of such kind of nanoparticles with the heavy metal ions is a very sensitive hyperfine specroscopy technique called the perturbed angular correlation technique (PAC).

Dash, Monika

2013-01-01

43

Studies on the use of inorganic gels in the removal of heavy metals  

Energy Technology Data Exchange (ETDEWEB)

Chromium ferrocyanide gel shows a great ability to remove heavy metal ions from wastewaters. Sorption of copper, cobalt, lead, iron, aluminum, magnesium, and other metal ions is described. The material can be effectively utilized in ion exchange systems and in batch operations. (3 graphs, 7 references, 1 table)

Srivastava, S.K.; Bhattacharjee, G.; Sharma, A.K.; Oberoi, C.K.

1980-01-01

44

The removal of heavy metals in urban runoff by sorption on mulch  

Energy Technology Data Exchange (ETDEWEB)

A series of adsorption experiments was conducted in order to assess the ability of three mulches to remove several of the heavy metal ions typically encountered in urban runoff. Three types of mulch, cypress bark (C), hardwood bark (H), and pine bark nugget (P), were selected as potential sorbents to capture heavy metals in urban runoff. The hardwood bark (H) mulch had the best physicochemical properties for adsorption of heavy metal ions. In addition, because of its fast removal rate and acceptably high capacity for all the heavy metal ions, it was concluded that the H mulch is the best of the three adsorbents for treatment of urban runoff containing trace amounts of heavy metals. In order to investigate the sorption isotherm, two equilibrium models, the Freundlich and Langmuir isotherms, were analyzed. The sorption of these metals on H mulch conformed to the linear form of the Langmuir adsorption equation. At pH 5 and 6, the Langmuir constants (S{sub m}) for each metal were found to be 0.324 and 0.359 mmol/g (Cu); 0.306 and 0.350 mmol/g (Pb); and 0.185 and 0.187 mmol/g (Zn) at 25 deg. C. - Capsule: Hardwood bark had the best physicochemical properties for adsorption of metal ions.

Jang, Am [Department of Civil and Environmental Engineering, University of Cincinnati, Cincinnati, OH (United States); Seo, Youngwoo [Department of Civil and Environmental Engineering, University of Cincinnati, Cincinnati, OH (United States); Bishop, Paul L. [Department of Civil and Environmental Engineering, University of Cincinnati, Cincinnati, OH (United States)]. E-mail: paul.bishop@uc.edu

2005-01-01

45

The removal of heavy metals in urban runoff by sorption on mulch  

International Nuclear Information System (INIS)

[en] A series of adsorption experiments was conducted in order to assess the ability of three mulches to remove several of the heavy metal ions typically encountered in urban runoff. Three types of mulch, cypress bark (C), hardwood bark (H), and pine bark nugget (P), were selected as potential sorbents to capture heavy metals in urban runoff. The hardwood bark (H) mulch had the best physicochemical properties for adsorption of heavy metal ions. In addition, because of its fast removal rate and acceptably high capacity for all the heavy metal ions, it was concluded that the H mulch is the best of the three adsorbents for treatment of urban runoff containing trace amounts of heavy metals. In order to investigate the sorption isotherm, two equilibrium models, the Freundlich and Langmuir isotherms, were analyzed. The sorption of these metals on H mulch conformed to the linear form of the Langmuir adsorption equation. At pH 5 and 6, the Langmuir constants (Sm) for each metal were found to be 0.324 and 0.359 mmol/g (Cu); 0.306 and 0.350 mmol/g (Pb); and 0.185 and 0.187 mmol/g (Zn) at 25 deg. C. - Capsule: Hardwood bark had the best physicochemical properties for adsorption of metal ions

2005-01-01

46

Method for removal of heavy metal from molten salt in IFR fuel pyroprocessing  

Energy Technology Data Exchange (ETDEWEB)

This report details the pyrometallurgical process for recycling spent metal fuels from the Integral Fast Reactor (IFR) which involves electrorefining spent fuel in a molten salt electrolyte (LiCl-KCI-U/PuCl{sub 3}) at 500{degree}C. The total heavy metal chloride concentration in the salt will be about 2 mol %. At some point, the concentrations of alkali, alkaline earth, and rare earth fission products in the salt must be reduced to lower the amount of heat generated in the electrorefiner. The heavy metal concentration in the salt must be reduced before removing the fission products from the salt. The operation uses a lithium-cadmium alloy anode that is solid at 500{degree}C, a solid mandrel cathode with a ceramic catch crucible below to collect heavy metal that falls off it, and a liquid cadmium cathode. The design criteria that had to be met by this equipment included the following: (1) control of the reduction rate by lithium, (2) good separation between heavy metal and rare earths, and (3) the capability to collect heavy metal and rare earths over a wide range of salt compositions. In tests conducted in an engineering-scale electrorefiner (10 kg uranium per cathode), good separation was achieved while removing uranium and rare earths from the salt. Only 13% of the rare earths was removed, while 99.9% of the uranium in the salt was removed; subsequently, the rare earths were also reduced to low concentrations. The uranium concentration in the salt was reduced to 0.05 ppm after uranium and rare earths were transferred from the salt to a solid mandrel cathode with a catch crucible. Rare earth concentrations in the salt were reduced to less than 0.01 wt % in these operations. Similar tests are planned to remove plutonium from the salt in a laboratory-scale (100--300 g heavy metal) electrorefiner.

Gay, E.C.; Miller, W.E.; Laidler, J.J.

1994-02-01

47

Literature review on the use of bioaccumulation for heavy metal removal and recovery  

International Nuclear Information System (INIS)

Bioaccumulation of metals by microbes -- '' bioremoval'' -- is a powerful new technology for the concentration, recovery, and removal of toxic heavy metals and radionuclides from waste streams and contaminated environments. Algae are particularly well suited for metal bioremoval. A recent commercial application of bioremoval utilizes inert (dead) immobilized microalgae biomass as ion exchange materials for the removal of heavy metals from industrial waste waters. Also, living microalgal cultures have been used to remove metals from mine effluents. Microbial cells and biomass can bioaccumulate metals and radionuclides by a large variety of mechanisms, both dependent and independent of cell metabolism. Microbial cell walls can act as ion exchange and metal complexation agents. Heavy metals can precipitate and even crystallize on cell surfaces. Metabolically produced hydrogen sulfide or other metabolic products can bioprecipitate heavy metals. Many microbes produce both intra- and extracellular metal complexing agents which could be considered in practical metal removal processes. Bioremoval processes are greatly affected by the microbial species and even strain used, pH, redox potential, temperature, and other conditions under which the microbes are grown. Development of practical applications of bioremoval requires applies research using the particular waste solutions to be treated, or close simulations thereof. From a practical perspective, the selection of the microbial biomass and the process for contacting the microbial biomass with the metal containing solutions are the key issues. Much of the recent commercial R ampersand D has emphasized commercially available, inert, microbial biomass sources as these can be acquired in sufficient quantities at affordable costs. The fundamental research and practical applications of bioaccumulation by microalgae suggests these organisms warrant a high priority in the development of advanced bioremoval processes.

1991-01-01

48

Microbial and plant derived biomass for removal of heavy metals from wastewater.  

UK PubMed Central (United Kingdom)

Discharge of heavy metals from metal processing industries is known to have adverse effects on the environment. Conventional treatment technologies for removal of heavy metals from aqueous solution are not economical and generate huge quantity of toxic chemical sludge. Biosorption of heavy metals by metabolically inactive non-living biomass of microbial or plant origin is an innovative and alternative technology for removal of these pollutants from aqueous solution. Due to unique chemical composition biomass sequesters metal ions by forming metal complexes from solution and obviates the necessity to maintain special growth-supporting conditions. Biomass of Aspergillus niger, Penicillium chrysogenum, Rhizopus nigricans, Ascophyllum nodosum, Sargassum natans, Chlorella fusca, Oscillatoria anguistissima, Bacillus firmus and Streptomyces sp. have highest metal adsorption capacities ranging from 5 to 641 mg g(-1) mainly for Pb, Zn, Cd, Cr, Cu and Ni. Biomass generated as a by-product of fermentative processes offers great potential for adopting an economical metal-recovery system. The purpose of this paper is to review the available information on various attributes of utilization of microbial and plant derived biomass and explores the possibility of exploiting them for heavy metal remediation.

Ahluwalia SS; Goyal D

2007-09-01

49

Microbial and plant derived biomass for removal of heavy metals from wastewater.  

Science.gov (United States)

Discharge of heavy metals from metal processing industries is known to have adverse effects on the environment. Conventional treatment technologies for removal of heavy metals from aqueous solution are not economical and generate huge quantity of toxic chemical sludge. Biosorption of heavy metals by metabolically inactive non-living biomass of microbial or plant origin is an innovative and alternative technology for removal of these pollutants from aqueous solution. Due to unique chemical composition biomass sequesters metal ions by forming metal complexes from solution and obviates the necessity to maintain special growth-supporting conditions. Biomass of Aspergillus niger, Penicillium chrysogenum, Rhizopus nigricans, Ascophyllum nodosum, Sargassum natans, Chlorella fusca, Oscillatoria anguistissima, Bacillus firmus and Streptomyces sp. have highest metal adsorption capacities ranging from 5 to 641 mg g(-1) mainly for Pb, Zn, Cd, Cr, Cu and Ni. Biomass generated as a by-product of fermentative processes offers great potential for adopting an economical metal-recovery system. The purpose of this paper is to review the available information on various attributes of utilization of microbial and plant derived biomass and explores the possibility of exploiting them for heavy metal remediation. PMID:16427277

Ahluwalia, Sarabjeet Singh; Goyal, Dinesh

2006-01-19

50

Use of electrocoagulation for removal of heavy metals in industrial wastewaters  

Energy Technology Data Exchange (ETDEWEB)

A wide variety of contaminants (heavy metals, suspended solids, colloids, oils, organics) have been successfully removed from wastewater using an electrocoagulation process. An innovative electrocoagulation system is described. This process involves a procedure which subjects dissolved and suspended wastewater contaminants to the simultaneous addition of metal ions in the presence of direct current. During the treatment process ionic and other charged particles in the wastewater are neutralized with oppositely charged ions generating the coagulation of contaminants: The process is called CURE, and presented here with application to wastewaters containing mainly heavy metals.

Dalrymple, C.W. [Hydrologics, Inc., Englewood, CO (United States)

1995-07-01

51

Heavy metals removal from aqueous solutions and wastewaters by using various byproducts.  

UK PubMed Central (United Kingdom)

Water contamination with heavy metals (HM) represents a potential threat to humans, animals and plants, and thus removal of these metals from contaminated waters has received increasing attention. The present study aimed to assess the efficiency of some low cost sorbents i.e., chitosan (CH), egg shell (ES), humate potassium (HK), and sugar beet factory lime (SBFL) for removal of cadmium (Cd), copper (Cu), lead (Pb) and zinc (Zn) from wastewaters. For this purpose batch equilibrium experiments were conducted with aqueous solutions containing various concentrations of the metals and sorbents in a mono-metal and competitive sorption system. Sorption isotherms were developed, and sorption parameters were determined. The potential applicability of the tested sorbents in the removal of Cd, Cu, and Zn from contaminated wastewaters was also investigated by equilibrating different sorbents and water ratios. Chitosan expressed the highest affinity for the metals followed by SBFL, ES, and HK. Nearly 100% of the metals were removed from aqueous solutions with the lowest initial metal concentrations by the sorbents especially CH and SBFL. However, the sorption efficiency decreased as the initial metal concentrations increased. Competition among the four metals changed significantly their distribution coefficient (Kd) values with the sorbents. The selectivity sequence of the metals was: Pb > Cu > Zn > Cd. The metal removal from the wastewaters varied from 72, 69, and 60 to nearly 100% for Cd, Cu and Zn, respectively. The efficiency of the studied byproducts in removing metals from the wastewaters differed based on the source of contamination and metal concentrations. Cadmium removal percentages by HK and CH were higher than SBFL and ES. The HK and CH exhibited the highest removal percentage of Cu from water with high concentrations. The SBFL and ES revealed the highest removal percentage of Zn from water with high concentrations. The results, demonstrate a high potential of CH, SBFL, HK, and ES for the remediation of HM contaminated wastewaters.

Shaheen SM; Eissa FI; Ghanem KM; Gamal El-Din HM; Al Anany FS

2013-10-01

52

Heavy metal removal by caustic-treated yeast immobilized in alginate  

Energy Technology Data Exchange (ETDEWEB)

Saccharomyces cerevisiae yeast biomass was treated with hot alkali to increase its biosorption capacity for heavy metals and then was immobilized in alginate gel. Biosorption capacities for Cu{sup 2+}, Cd{sup 2+}, and Zn{sup 2+} on alginate gel, native yeast, native yeast immobilized in alginate gel, and caustic-treated yeast immobilized in alginate gel were all compared. Immobilized yeasts could be reactivated and reused in a manner similar to the ion exchange resins. Immobilized caustic-treated yeast has high heavy metal biosorption capacity and high metal removal efficiency in a rather wide acidic pH region. The biosorption isotherm of immobilized caustic-treated yeast was studied, and empirical equations were obtained. The initial pH of polluted water affected the metal removal efficiency significantly, and the equilibrium biosorption capacity seemed to be temperature independent at lower initial metal concentrations.

Lu, Y.; Wilkins, E. [Univ. of New Mexico, Albuquerque, NM (United States)

1995-12-31

53

Selective removal of heavy metals from metal-bearing wastewater in a cascade line reactor.  

UK PubMed Central (United Kingdom)

GOAL, SCOPE AND BACKGROUND: This paper is a part of the research work on 'Integrated treatment of industrial wastes towards prevention of regional water resources contamination - INTREAT' the project. It addresses the environmental pollution problems associated with solid and liquid waste/effluents produced by sulfide ore mining and metallurgical activities in the Copper Mining and Smelting Complex Bor (RTB-BOR), Serbia. However, since the minimum solubility for the different metals usually found in the polluted water occurs at different pH values and the hydroxide precipitates are amphoteric in nature, selective removal of mixed metals could be achieved as the multiple stage precipitation. For this reason, acid mine water had to be treated in multiple stages in a continuous precipitation system-cascade line reactor. MATERIALS AND METHODS: All experiments were performed using synthetic metal-bearing effluent with chemical a composition similar to the effluent from open pit, Copper Mining and Smelting Complex Bor (RTB-BOR). That effluent is characterized by low pH (1.78) due to the content of sulfuric acid and heavy metals, such as Cu, Fe, Ni, Mn, Zn with concentrations of 76.680, 26.130, 0.113, 11.490, 1.020 mg/dm3, respectively. The cascade line reactor is equipped with the following components: for feeding of effluents, for injection of the precipitation agent, for pH measurements and control, and for removal of the process gases. The precipitation agent was 1M NaOH. In each of the three reactors, a changing of pH and temperature was observed. In order to verify. efficiency of heavy metals removal, chemical analyses of samples taken at different pH was done using AES-ICP. RESULTS: Consumption of NaOH in reactors was 370 cm3, 40 cm3 and 80 cm3, respectively. Total time of the experiment was 4 h including feeding of the first reactor. The time necessary to achieve the defined pH value was 25 min for the first reactor and 13 min for both second and third reactors. Taking into account the complete process in the cascade line reactor, the difference between maximum and minimum temperature was as low as 6 degrees C. The quantity of solid residue in reactors respectively was 0.62 g, 2.05 g and 3.91 g. In the case of copper, minimum achieved concentration was 0.62 mg/dm3 at pH = 10.4. At pH = 4.50 content of iron has rapidly decreased to < 0.1 mg/dm3 and maintained constant at all higher pH values. That means that precipitation has already ended at pH=4.5 and maximum efficiency of iron removal was 99.53%. The concentration of manganese was minimum at pH value of 11.0. Minimum obtained concentration of Zn was 2.18 mg/dm3 at a pH value of 11. If pH value is higher than 11, Zn can be re-dissolved. The maximum efficiency of Ni removal reached 76.30% at a pH value of 10.4. DISCUSSION: Obtained results show that efficiency of copper, iron and manganese removal is very satisfactory (higher than 90%). The obtained efficiency of Zn and Ni removal is lower (72.30% and 76.31%, respectively). The treated effluent met discharge water standard according to The Council Directive 76/464/EEC on pollution caused by certain dangerous substances into the aquatic environment of the Community. Maximum changing of temperature during the whole process was 6 degrees C. CONCLUSION: This technology, which was based on inducing chemical precipitation of heavy metals is viable for selective removal of heavy metals from metal-bearing effluents in three reactor systems in a cascade line. RECOMMENDATIONS AND PERSPECTIVES: The worldwide increasing concern for the environment and guidelines regarding effluent discharge make their treatment necessary for safe discharge in water receivers. In the case where the effluents contain valuable metals, there is also an additional economic interest to recover these metals and to recycle them as secondary raw materials in different production routes.

Pavlovi? J; Stopi? S; Friedrich B; Kamberovi? Z

2007-11-01

54

Effects of pulse current on energy consumption and removal of heavy metals during electrodialytic soil remediation  

DEFF Research Database (Denmark)

The aims of this paper were to investigate the possibility for energy saving when using a pulsed electric field during electrodialytic soil remediation (EDR) and the effect of the pulsed current on removal of heavy metals. Eight experiments with constant and pulse current in the different industrially polluted soils were performed. At a current density of 0.1mA/cm2 in soil 1 and 0.2mA/cm2 in soil 2, there was no difference on energy consumption and removal of heavy metals between pulse current and constant current experiments, but at higher current experiments (i.e., 0.2mA/cm2 in soil 1 and 0.8mA/cm2 in soil 2) the energy was saved 67% and 60% and the removal of heavy metals was increased 17–76% and 31–51% by pulse current in soil 1 and soil 2, respectively. When comparing the voltage drop at different parts of EDR cells, it was found that the voltage drop of the area across cation exchange membrane was the major contributor of energy consumption, and the pulse current could decrease the voltage drop of this part effectively. The overall removal of heavy metals in soil 1 (6–54%) was much higher than soil 2 (1–17%) due to the different acidification process and chemical speciation of heavy metals reflected by sequential extraction analysis. Among all experiments, the highest removal efficiency occurred in pulse current experiment of soil 1, where 54% of Cu and 30% of As were removed.

Sun, Tian R.; Ottosen, Lisbeth M.

2012-01-01

55

Removal Characteristics of Heavy Metals by Continuous Neutralization of Plating Wastewater with Waste-Oyster Shells  

Energy Technology Data Exchange (ETDEWEB)

Objective of the research is to determine the practical running parameters for neutralization and removal of heavy metals from plating wastewater with waste-oyster shells by the Bohart-Adams equation. Waste-oyster shells discharged from the domestic oyster culturing fields cause a serious ocean environmental pollution. However, it is expected that those are able to be recycled for removal of heavy metals through neutralization of plating wastewater because the shells contain approximate 93% CaCO{sub 3} and have multi-pore voids. By applying the results of the continuous experiments to Bohart-Adams equation, service time decreases in the order of Cr > Fe > Cu, while removal efficiencies of metals become less in the order of Fe > Cr > Cu. (author). 9 refs., 4 tabs., 8 figs.

Kim, Hyeong Seok; Song, Dong Keun [Silla University, Pusan (Korea); Sung, Nak Chang [Dong-A University, Pusan (Korea)

1998-09-30

56

Removal of Heavy Metal from Contaminated Water by Biopolymer Crab Shell Chitosan  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The study focuses on potential of using crab shell chitosan as a low-cost biosorbent, for heavy metals removal from aqueous solutions in an adsorption filtration system. Chitosan was synthesized from chitin by the treatment of strong alkali solution under reflux condition and chitin was extracted fr...

M.S. Rana; M.A. Halim; S. Safiullah; M. Mamun Mollah; M.S. Azam; M.A. Goni; M. Kamal Hossain; M.M. Rana

57

Sorptive removal of technetium from alkaline heavy metals sludge filtrate containing nitrate ion  

International Nuclear Information System (INIS)

A so-called raffinate waste stream is generated from various uranium recovery and equipment cleaning and decontamination activities at the X-705 facility of the Portsmouth (Ohio) Gaseous Diffusion Plant (PORTS). The day-to-day composition of this waste stream may be variable, but it is generally characterized by high concentrations of nitric acid, toxic heavy metals, and low levels of radioactive nuclides (235U, 99Tc). Some laboratory analysis results for a subsample of typical raffinate from PORTS are given. This paper also lists some regulatory water standards for comparison purposes (note that different standards may be applicable, depending on jurisdiction and intended water usage). Current treatment protocol for the raffinate stream consists of the following: first, dilution and pH adjustment (to a value of about 8.5) to precipitate the hydrolyzable heavy metals; then, filtration to remove the heavy metals sludge (HMS); next, processing of the filtrate with a strong-base anion exchange resin to remove the soluble pertechnetate (TcO4-) ion; next, biodenitrification; and last, sewage disposal. The effectiveness of the heavy metals precipitation unit operation is illustrated; most heavy metals (including uranium) are reduced from very high concentrations in the raffinate to levels in the HMS filtrate which are below regulatory concern

1988-01-01

58

Heavy metal removal from municipal solid waste fly ash by chlorination and thermal treatment.  

UK PubMed Central (United Kingdom)

Municipal solid waste (MSW) fly ash is classified as a hazardous material because it contains high amounts of heavy metals. For decontamination, MSW fly ash is first mixed with alkali or alkaline earth metal chlorides (e.g. calcium chloride) and water, and then the mixture is pelletized and treated in a rotary reactor at about 1000 degrees C. Volatile heavy metal compounds are formed and evaporate. In this paper, the effect of calcium chloride addition, gas velocity, temperature and residence time on the separation of heavy metals are studied. The fly ash was sampled at the waste-to-energy plant Fernwärme Wien/Spittelau (Vienna, Austria). The results were obtained from batch tests performed in an indirectly heated laboratory-scale rotary reactor. More than 90% of Cd and Pb and about 60% of Cu and 80% of Zn could be removed in the experiments.

Nowak B; Pessl A; Aschenbrenner P; Szentannai P; Mattenberger H; Rechberger H; Hermann L; Winter F

2010-07-01

59

Heavy metal removal from municipal solid waste fly ash by chlorination and thermal treatment.  

Science.gov (United States)

Municipal solid waste (MSW) fly ash is classified as a hazardous material because it contains high amounts of heavy metals. For decontamination, MSW fly ash is first mixed with alkali or alkaline earth metal chlorides (e.g. calcium chloride) and water, and then the mixture is pelletized and treated in a rotary reactor at about 1000 degrees C. Volatile heavy metal compounds are formed and evaporate. In this paper, the effect of calcium chloride addition, gas velocity, temperature and residence time on the separation of heavy metals are studied. The fly ash was sampled at the waste-to-energy plant Fernwärme Wien/Spittelau (Vienna, Austria). The results were obtained from batch tests performed in an indirectly heated laboratory-scale rotary reactor. More than 90% of Cd and Pb and about 60% of Cu and 80% of Zn could be removed in the experiments. PMID:20356672

Nowak, B; Pessl, A; Aschenbrenner, P; Szentannai, P; Mattenberger, H; Rechberger, H; Hermann, L; Winter, F

2010-03-09

60

Heavy metal removal from municipal solid waste fly ash by chlorination and thermal treatment  

Energy Technology Data Exchange (ETDEWEB)

Municipal solid waste (MSW) fly ash is classified as a hazardous material because it contains high amounts of heavy metals. For decontamination, MSW fly ash is first mixed with alkali or alkaline earth metal chlorides (e.g. calcium chloride) and water, and then the mixture is pelletized and treated in a rotary reactor at about 1000deg. C. Volatile heavy metal compounds are formed and evaporate. In this paper, the effect of calcium chloride addition, gas velocity, temperature and residence time on the separation of heavy metals are studied. The fly ash was sampled at the waste-to-energy plant Fernwaerme Wien/Spittelau (Vienna, Austria). The results were obtained from batch tests performed in an indirectly heated laboratory-scale rotary reactor. More than 90% of Cd and Pb and about 60% of Cu and 80% of Zn could be removed in the experiments.

Nowak, B., E-mail: benedikt.nowak@tuwien.ac.at [Institute of Chemical Engineering/Vienna University of Technology, Getreidemarkt 9/166, A-1060 Vienna (Austria); Pessl, A. [Institute of Chemical Engineering/Vienna University of Technology, Getreidemarkt 9/166, A-1060 Vienna (Austria); Aschenbrenner, P. [Institute for Water Quality, Resource and Waste Management/Vienna University of Technology, Karlsplatz 13/226, A-1040 Vienna (Austria); Szentannai, P. [Institute of Chemical Engineering/Vienna University of Technology, Getreidemarkt 9/166, A-1060 Vienna (Austria); Mattenberger, H. [ASH DEC Umwelt AG, Donaufelderstrasse 101/4/5, A-1210 Vienna (Austria); Rechberger, H. [Institute for Water Quality, Resource and Waste Management/Vienna University of Technology, Karlsplatz 13/226, A-1040 Vienna (Austria); Hermann, L. [ASH DEC Umwelt AG, Donaufelderstrasse 101/4/5, A-1210 Vienna (Austria); Winter, F., E-mail: franz.winter@tuwien.ac.at [Institute of Chemical Engineering/Vienna University of Technology, Getreidemarkt 9/166, A-1060 Vienna (Austria)

2010-07-15

 
 
 
 
61

Metabolic Engineering for Heavy Metal and Actinide Removal.  

Science.gov (United States)

Engineering hydrogen sulfide production and cadmium removal by expression of the thiosulfate reductase gene (phsABC) from Salmonella enterica serovar Typhimurium in Escherichia coli. The thiosulfate reductase operon (phsABC) from Salmonella typhimurium wa...

J. D. Keasling

2005-01-01

62

Comparison of Amberlite IR 120 and dolomite's performances for removal of heavy metals  

Energy Technology Data Exchange (ETDEWEB)

The presence of heavy metals in the environment is major concern due to their toxicity. Contamination of heavy metals in water supplies has steadily increased over the last years as a result of over population and expansion of industrial activities. A strong cation-exchange resin, Amberlite IR 120 and a natural zeolite, dolomite were used for the removal of lead(II) and cadmium(II). The optimum conditions were determined in a batch system as concentration range was between 5 and 100 mg/L, pH range between 1 and 8, contact time between 5 and 90 min, and the amount of adsorbent was from 0.1 to 1 g. A constant stirring speed, 2000 rpm, was chosen during all of the experiments. The optimum conditions were found to be a concentration of 20 mg/L, pH of 5, contact time of 60 min and 0.5 g of adsorbent. Also, for investigation of exchange equilibria different amounts of ion exchange resin and dolomite were contacted with a fixed volume and concentration of a heavy metal bearing solutions. Sorption data have been interpreted in terms of Langmuir and Freundlich equations. The effect of adsorption temperature on the heavy metals adsorption onto dolomite was investigated at three different temperatures (20, 40 and 60 deg. C). Thermodynamic parameters were calculated. The results obtained show that the Amberlite IR 120 strong cation-exchange resin and dolomite performed well for the removal of these heavy metals. As a low cost adsorbent, dolomite can preferable for removal of heavy metals from wastewaters.

Kocaoba, Sevgi [Yildiz Technical University, Faculty of Art and Science, Department of Chemistry, Davutpasa Cad. No: 127, 34210 Davutpasa, Istanbul (Turkey)]. E-mail: kocaoba@yildiz.edu.tr

2007-08-17

63

Comparison of Amberlite IR 120 and dolomite's performances for removal of heavy metals  

International Nuclear Information System (INIS)

The presence of heavy metals in the environment is major concern due to their toxicity. Contamination of heavy metals in water supplies has steadily increased over the last years as a result of over population and expansion of industrial activities. A strong cation-exchange resin, Amberlite IR 120 and a natural zeolite, dolomite were used for the removal of lead(II) and cadmium(II). The optimum conditions were determined in a batch system as concentration range was between 5 and 100 mg/L, pH range between 1 and 8, contact time between 5 and 90 min, and the amount of adsorbent was from 0.1 to 1 g. A constant stirring speed, 2000 rpm, was chosen during all of the experiments. The optimum conditions were found to be a concentration of 20 mg/L, pH of 5, contact time of 60 min and 0.5 g of adsorbent. Also, for investigation of exchange equilibria different amounts of ion exchange resin and dolomite were contacted with a fixed volume and concentration of a heavy metal bearing solutions. Sorption data have been interpreted in terms of Langmuir and Freundlich equations. The effect of adsorption temperature on the heavy metals adsorption onto dolomite was investigated at three different temperatures (20, 40 and 60 deg. C). Thermodynamic parameters were calculated. The results obtained show that the Amberlite IR 120 strong cation-exchange resin and dolomite performed well for the removal of these heavy metals. As a low cost adsorbent, dolomite can preferable for removal of heavy metals from wastewaters

2007-08-17

64

Feasibility of bioleaching combined with Fenton-like reaction to remove heavy metals from sewage sludge.  

Science.gov (United States)

Feasibility of bioleaching combining with Fenton-like reaction to remove heavy metals from sewage sludge was investigated. After 5-day bioleaching, the sludge pH decreased from 6.95 to 2.50, which satisfied the acidic conditions for Fenton-like reaction. Meanwhile, more than 50% of sludge-borne heavy metals were dissolved except for Pb. The bioleached sludge was further oxidized with Fenton-like reaction, with an optimal H2O2 dosage of 5 g/L, the Cu, Zn, Pb and Cd removal reached up to 75.3%, 72.6%, 34.5% and 65.4%, respectively, and the residual content of heavy metals in treated sludge meets the requirement of Disposal of Sludge from Municipal Wastewater Treatment Plant - Control Standards for Agricultural Use (CJ/T 309-2009) of China for A grade sludge. Bioleaching combined with Fenton-like reaction was the most effective method for heavy metal removal, compared with 15-day bioleaching and inorganic acid leaching with 10% H2SO4, 10% HCl and 10% HNO3. PMID:23765003

Zhu, Yi; Zeng, Guangming; Zhang, Panyue; Zhang, Chang; Ren, Miaomiao; Zhang, Jiachao; Chen, Ming

2013-05-24

65

Feasibility of bioleaching combined with Fenton-like reaction to remove heavy metals from sewage sludge.  

UK PubMed Central (United Kingdom)

Feasibility of bioleaching combining with Fenton-like reaction to remove heavy metals from sewage sludge was investigated. After 5-day bioleaching, the sludge pH decreased from 6.95 to 2.50, which satisfied the acidic conditions for Fenton-like reaction. Meanwhile, more than 50% of sludge-borne heavy metals were dissolved except for Pb. The bioleached sludge was further oxidized with Fenton-like reaction, with an optimal H2O2 dosage of 5 g/L, the Cu, Zn, Pb and Cd removal reached up to 75.3%, 72.6%, 34.5% and 65.4%, respectively, and the residual content of heavy metals in treated sludge meets the requirement of Disposal of Sludge from Municipal Wastewater Treatment Plant - Control Standards for Agricultural Use (CJ/T 309-2009) of China for A grade sludge. Bioleaching combined with Fenton-like reaction was the most effective method for heavy metal removal, compared with 15-day bioleaching and inorganic acid leaching with 10% H2SO4, 10% HCl and 10% HNO3.

Zhu Y; Zeng G; Zhang P; Zhang C; Ren M; Zhang J; Chen M

2013-08-01

66

Method for removing heavy metal and nitrogen oxides from flue gas, device for removing heavy metal and nitrogen oxides from flue gas  

Energy Technology Data Exchange (ETDEWEB)

A method for the simultaneous removal of oxides and heavy metals from a fluid is provided comprising combining the fluid with compounds containing alkali and sulfur to create a mixture; spray drying the mixture to create a vapor phase and a solid phase; and isolating the vapor phase from the solid phase. A device is also provided comprising a means for spray-drying flue gas with alkali-sulfide containing liquor at a temperature sufficient to cause the flue gas to react with the compounds so as to create a gaseous fraction and a solid fraction and a means for directing the gaseous fraction to a fabric filter.

Huang, Hann-Sheng; Livengood, Charles David

1997-12-01

67

Efficiency of lipopeptide biosurfactants in removal of petroleum hydrocarbons and heavy metals from contaminated soil.  

UK PubMed Central (United Kingdom)

This study describes the potential application of lipopeptide biosurfactants in removal of petroleum hydrocarbons and heavy metals from the soil samples collected from industrial dumping site. High concentrations of heavy metals (like iron, lead, nickel, cadmium, copper, cobalt and zinc) and petroleum hydrocarbons were present in the contaminated soil samples. Lipopeptide biosurfactant, consisting of surfactin and fengycin was obtained from Bacillus subtilis A21. Soil washing with biosurfactant solution removed significant amount of petroleum hydrocarbon (64.5 %) and metals namely cadmium (44.2 %), cobalt (35.4 %), lead (40.3 %), nickel (32.2 %), copper (26.2 %) and zinc (32.07 %). Parameters like surfactant concentration, temperature, agitation condition and pH of the washing solution influenced the pollutant removing ability of biosurfactant mixture. Biosurfactant exhibited substantial hydrocarbon solubility above its critical micelle concentration. During washing, 50 % of biosurfactant was sorbed to the soil particles decreasing effective concentration during washing process. Biosurfactant washed soil exhibited 100 % mustard seed germination contradictory to water washed soil where no germination was observed. The results indicate that the soil washing with mixture of lipopeptide biosurfactants at concentrations above its critical micelle concentration can be an efficient and environment friendly approach for removing pollutants (petroleum hydrocarbon and heavy metals) from contaminated soil.

Singh AK; Cameotra SS

2013-05-01

68

Efficiency of lipopeptide biosurfactants in removal of petroleum hydrocarbons and heavy metals from contaminated soil.  

Science.gov (United States)

This study describes the potential application of lipopeptide biosurfactants in removal of petroleum hydrocarbons and heavy metals from the soil samples collected from industrial dumping site. High concentrations of heavy metals (like iron, lead, nickel, cadmium, copper, cobalt and zinc) and petroleum hydrocarbons were present in the contaminated soil samples. Lipopeptide biosurfactant, consisting of surfactin and fengycin was obtained from Bacillus subtilis A21. Soil washing with biosurfactant solution removed significant amount of petroleum hydrocarbon (64.5 %) and metals namely cadmium (44.2 %), cobalt (35.4 %), lead (40.3 %), nickel (32.2 %), copper (26.2 %) and zinc (32.07 %). Parameters like surfactant concentration, temperature, agitation condition and pH of the washing solution influenced the pollutant removing ability of biosurfactant mixture. Biosurfactant exhibited substantial hydrocarbon solubility above its critical micelle concentration. During washing, 50 % of biosurfactant was sorbed to the soil particles decreasing effective concentration during washing process. Biosurfactant washed soil exhibited 100 % mustard seed germination contradictory to water washed soil where no germination was observed. The results indicate that the soil washing with mixture of lipopeptide biosurfactants at concentrations above its critical micelle concentration can be an efficient and environment friendly approach for removing pollutants (petroleum hydrocarbon and heavy metals) from contaminated soil. PMID:23681773

Singh, Anil Kumar; Cameotra, Swaranjit Singh

2013-05-17

69

Efficiency of lipopeptide biosurfactants in removal of petroleum hydrocarbons and heavy metals from contaminated soil.  

UK PubMed Central (United Kingdom)

This study describes the potential application of lipopeptide biosurfactants in removal of petroleum hydrocarbons and heavy metals from the soil samples collected from industrial dumping site. High concentrations of heavy metals (like iron, lead, nickel, cadmium, copper, cobalt and zinc) and petroleum hydrocarbons were present in the contaminated soil samples. Lipopeptide biosurfactant, consisting of surfactin and fengycin was obtained from Bacillus subtilis A21. Soil washing with biosurfactant solution removed significant amount of petroleum hydrocarbon (64.5 %) and metals namely cadmium (44.2 %), cobalt (35.4 %), lead (40.3 %), nickel (32.2 %), copper (26.2 %) and zinc (32.07 %). Parameters like surfactant concentration, temperature, agitation condition and pH of the washing solution influenced the pollutant removing ability of biosurfactant mixture. Biosurfactant exhibited substantial hydrocarbon solubility above its critical micelle concentration. During washing, 50 % of biosurfactant was sorbed to the soil particles decreasing effective concentration during washing process. Biosurfactant washed soil exhibited 100 % mustard seed germination contradictory to water washed soil where no germination was observed. The results indicate that the soil washing with mixture of lipopeptide biosurfactants at concentrations above its critical micelle concentration can be an efficient and environment friendly approach for removing pollutants (petroleum hydrocarbon and heavy metals) from contaminated soil.

Singh AK; Cameotra SS

2013-10-01

70

Effects of impurities on the removal of heavy metals by natural limestones in aqueous systems.  

UK PubMed Central (United Kingdom)

Effects of impurities on the removal of heavy metals by natural limestones in aqueous solutions were studied by evaluating various factors including limestone concentration, pH, contact time and temperature. Solutions of Pb(II), Cd(II), Cu(II) and Zn(II), prepared from chloride reagents at a concentration of 10 mg/L, were studied in a batch method. Four natural limestone samples, collected from the Campanian-Maastrichtian limestone beds in Tunisia, were used as adsorbents. Sorption experiments indicated that high removal efficiencies could be achieved. Limestone samples containing impurities, such as silica, iron/aluminum oxides and different kinds of clay minerals, demonstrated enhanced sorption capacity, nearing 100% removal in some cases. Kinetic experiments showed that the sorption of metal ions occurred rapidly at a low coverage stage, and that solutions were nearly at equilibrium after 60 min. Data trends generally fit pseudo-second order kinetic, and intra-particle diffusion, models. The following conditions were found to promote optimum, or near-optimum, sorption of heavy metals: 1) contact time of more than 60 min, 2) pH = 5, 3) >3 g/L limestone concentration and 4) T = 35 °C. The results of this study suggest that the limestones from northern Tunisia, that contain higher amounts of silica and iron/aluminum oxides, are promising adsorbents for the effective removal of toxic heavy metals from wastewaters.

Sdiri A; Higashi T; Jamoussi F; Bouaziz S

2012-01-01

71

Removal of Heavy Metal from Contaminated Water by Biopolymer Crab Shell Chitosan  

Directory of Open Access Journals (Sweden)

Full Text Available The study focuses on potential of using crab shell chitosan as a low-cost biosorbent, for heavy metals removal from aqueous solutions in an adsorption filtration system. Chitosan was synthesized from chitin by the treatment of strong alkali solution under reflux condition and chitin was extracted from crab shell followed by decalcification and deproteinization treatment. Spectrometric (AA and UV) method was employed to detect the heavy metals concentration. Prepared 10 mg L-1 solutions of zinc, lead, cadmium, cobalt, nickel, chromium, manganese and iron were passed through the 5 g of chitosan separately and it was found that chitosan was excellent adsorbent in removing mentioned heavy metals. The removal efficiency of chitosan was in the following order Mn>Cd>Zn>Co>Ni>Fe>Pb>Cr. The result also showed that the time required for 100% breakthrough of prepared chitosan for Mn and Zn was approximately 27 and 23 h whereas it was only 16 h for both Cr and Pb, respectively. The research revealed that prepared chitosan showed better removal performance for Mn, Cd, Zn whereas the removal efficiency was satisfactory for Co, Ni and Fe but it exhibited relatively least performance for Pb and Cr.

M.S. Rana; M.A. Halim; S. Safiullah; M. Mamun Mollah; M.S. Azam; M.A. Goni; M. Kamal Hossain; M.M. Rana

2009-01-01

72

USING BIOPOLYMERS TO REMOVE HEAVY METALS FROM SOIL AND WATER  

Science.gov (United States)

Chemical remediation of soils may involve the use of harsh chemicals that generate waste streams and may adversely affect the soil's integrity and ability to support vegetation. his paper reviews the promise of benign reagents such as biopolymers to extract metals. he biopolymers...

73

Removal Efficiency of Heavy Metals Using Various Resins and Natural Materials  

Directory of Open Access Journals (Sweden)

Full Text Available Heavy metals found in local water are an environmental concern. These metals are potentially harmful since they can bio-accumulate in organisms and have been classified as toxic and/or carcinogenic. In this study, water was collected from a shipyard located on a bayou. Various materials (chitosan, mixed bed and amphoteric resins) were tested to determine their efficiency for metal remediation. Inductively coupled plasma mass spectrometry (ICP/MS) was used to quantify the efficiency of the materials examined. Overall, amphoteric resin was found to be the most efficient for a greater number of metals examined (Al, Co, Cu, Fe, Mn), followed by mixed bed which most efficiently removed As and Fe. Chitosan showed the poorest efficiency for metal removal.

P.P. Vaughan; M.P. Bruns; C.L. Beck; M. Cochran

2012-01-01

74

Removal of Heavy Metals from Solid Wastes Leachates Coagulation-Flocculation Process  

Science.gov (United States)

The main objectives of present research were to determine heavy metals (Ni, Cd, Cr, Zn and Cu) and COD concentration in raw leachate in Esfahan (Iran) composting plant and to examine the application of coagulation-flocculation process for the treatment of raw leachates. Jar-test experiments were employed in order to determine the optimum conditions (effective dosage and optimum pH) for the removal of COD and heavy metals. Alum (aluminum sulphate) and Ferric chloride were tested as conventional coagulants. Ten times had taken sampling from leachates as standard methods in the composting plant prior to composting process. The results showed that Leachate pH was 4.3-5.9 and the average was 4.98±0.62. The concentration of Leachate pollutants were more than effluent standard limits (Environment protection Agency). And also the results indicated, Cd and Zn with concentration 0.46±0.41 and 5.81±3.69 mg L-1, had minimum and maximum levels, respectively. The results of coagulation and flocculation tests showed that in optimum conditions, the removal efficiency of heavy metals and COD by using alum were 77-91 and 21%, respectively. While removal of heavy metals and COD by ferric chloride were 68-85.5% and 28%, respectively. Also the residues of heavy metals after treatment get to under of standard limits of Iran EPA. The results have indicated optimum pH of two coagulants for leachate treatment was 6.5 and 10 and also effective coagulant dosages were 1400 and 1000 mg L-1 for alum and ferric chloride, respectively. In view of economical, ferric chloride is cost benefit. The physico-chemical process may be used as a useful pretreatment step, especially for fresh leachates.

Yousefi, Z.; Zazouli, M. A.

75

Removal of Heavy Metals from Solid Wastes Leachates Coagulation-Flocculation Process  

Directory of Open Access Journals (Sweden)

Full Text Available The main objectives of present research were to determine heavy metals (Ni, Cd, Cr, Zn and Cu) and COD concentration in raw leachate in Esfahan (Iran) composting plant and to examine the application of coagulation-flocculation process for the treatment of raw leachates. Jar-test experiments were employed in order to determine the optimum conditions (effective dosage and optimum pH) for the removal of COD and heavy metals. Alum (aluminum sulphate) and Ferric chloride were tested as conventional coagulants. Ten times had taken sampling from leachates as standard methods in the composting plant prior to composting process. The results showed that Leachate pH was 4.3-5.9 and the average was 4.98±0.62. The concentration of Leachate pollutants were more than effluent standard limits (Environment protection Agency). And also the results indicated, Cd and Zn with concentration 0.46±0.41 and 5.81±3.69 mg L-1, had minimum and maximum levels, respectively. The results of coagulation and flocculation tests showed that in optimum conditions, the removal efficiency of heavy metals and COD by using alum were 77-91 and 21%, respectively. While removal of heavy metals and COD by ferric chloride were 68-85.5% and 28%, respectively. Also the residues of heavy metals after treatment get to under of standard limits of Iran EPA. The results have indicated optimum pH of two coagulants for leachate treatment was 6.5 and 10 and also effective coagulant dosages were 1400 and 1000 mg L-1 for alum and ferric chloride, respectively. In view of economical, ferric chloride is cost benefit. The physico-chemical process may be used as a useful pretreatment step, especially for fresh leachates.

Z. Yousefi; M.A. Zazouli

2008-01-01

76

Sewage sludge ash to phosphorus fertiliser: Variables influencing heavy metal removal during thermochemical treatment  

International Nuclear Information System (INIS)

The aim of this study was to improve the removal of heavy metals from sewage sludge ash by a thermochemical process. The resulting detoxified ash was intended for use as a raw material rich in phosphorus (P) for inorganic fertiliser production. The thermochemical treatment was performed in a rotary kiln where the evaporation of relevant heavy metals was enhanced by additives. The four variables investigated for process optimisation were treatment temperature, type of additive (KCl, MgCl2) and its amount, as well as type of reactor (directly or indirectly heated rotary kiln). The removal rates of Cd, Cr, Cu, Ni, Pb, Zn and of Ca, P and Cl were investigated. The best overall removal efficiency for Cd, Cu, Pb and Zn could be found for the indirectly heated system. The type of additive was critical, since MgCl2 favours Zn- over Cu-removal, while KCl acts conversely. The use of MgCl2 caused less particle abrasion from the pellets in the kiln than KCl. In the case of the additive KCl, liquid KCl - temporarily formed in the pellets - acted as a barrier to heavy metal evaporation as long as treatment temperatures were not sufficiently high to enhance its reaction or evaporation.

2008-01-01

77

Sewage sludge ash to phosphorus fertiliser: variables influencing heavy metal removal during thermochemical treatment.  

Science.gov (United States)

The aim of this study was to improve the removal of heavy metals from sewage sludge ash by a thermochemical process. The resulting detoxified ash was intended for use as a raw material rich in phosphorus (P) for inorganic fertiliser production. The thermochemical treatment was performed in a rotary kiln where the evaporation of relevant heavy metals was enhanced by additives. The four variables investigated for process optimisation were treatment temperature, type of additive (KCl, MgCl(2)) and its amount, as well as type of reactor (directly or indirectly heated rotary kiln). The removal rates of Cd, Cr, Cu, Ni, Pb, Zn and of Ca, P and Cl were investigated. The best overall removal efficiency for Cd, Cu, Pb and Zn could be found for the indirectly heated system. The type of additive was critical, since MgCl(2) favours Zn- over Cu-removal, while KCl acts conversely. The use of MgCl(2) caused less particle abrasion from the pellets in the kiln than KCl. In the case of the additive KCl, liquid KCl - temporarily formed in the pellets - acted as a barrier to heavy metal evaporation as long as treatment temperatures were not sufficiently high to enhance its reaction or evaporation. PMID:18331787

Mattenberger, H; Fraissler, G; Brunner, T; Herk, P; Hermann, L; Obernberger, I

2008-03-10

78

Electrokinetic removal of selected heavy metals from soil  

Energy Technology Data Exchange (ETDEWEB)

The electrokinetic process is an emerging technology for in situ soil decontamination, in which chemical species, both ionic and nonionic, are transported to an electrode site in soil. These products are subsequently removed from the ground via collection systems engineered for each specific application. Electrokinetics refer to movement of water, ions and charged particles relative to one another under the action of an applied direct current electric field. In a porous compact matrix of surface charged particles such as soil, the ion-containing pore fluid may be made to flow to collection sites under the applied field. The work presented here describes part of the effort undertaken to investigate electrokinetically enhanced transport of soil contaminants in synthetic systems. The results of the laboratory study presented here indicated that electrokinetic enhancement of contaminant transport in soils is a viable technology; development of this technology for a wide range of applications hinges upon better understanding of the transient chemical and physical processes during application of current through soil/contaminant systems. 19 refs., 15 figs., 2 tabs.

Pamukcu, S. (Lehigh Univ., Bethlehem, PA (United States)); Wittle, J.K. (Electro-Petroleum, Inc., Wayne, PA (United States))

1992-08-01

79

Removal of heavy metals from wastewater with Bigadic (Tuerkiye) clinoptilolite  

Energy Technology Data Exchange (ETDEWEB)

In this study, Bigadic upper zone zeolitic tuff, which contains about 87% clinoptilolite was used as an ion exchanger for removal of Pb{sup ++}, Cu{sup ++}, Cd{sup ++} and Hg{sup ++}ions from wastewater. Bench scale experiments with two different glass columns, were carried out continuously under the closed/open circuit conditions. Before ion exchange tests, zeolite samples were treated with NaCl (6ml/min. and 42BV). The effects of particle size, bed volume, pH and flow rate on the ion exchange capacity were determined. Under the best operation conditions, the effect of initial influent solution concentration on ion exchange selectivity was tested. As a result, it was found that the Bigadic clinoptilolite had the following ion exchange capacities; Pb{sup ++}, 0.7540 meg/g; Cu{sup ++}, 0.6986 meg/g; Cd{sup ++}, 0.6580 meg/g; Hg{sup ++}, 0.5530 meg/g.

Kurama, Haldun; Kaya, Muammer [Osmangazi Univ., Eskisehir (Turkey). Mining Engineering Dept.

1995-07-01

80

Acidification of Harbour sediment and removal of heavy metals induced by water splitting in electrodialytic remediation.  

DEFF Research Database (Denmark)

Harbor sediments are often contaminated with heavy metals, which can be removed by electrodialytic remediation. Water splitting at the anion exchange membrane in contact with the contaminated material in electrodialytic remediation is highly important for the removal of heavy metals. Here it was investigated how acidification caused by water splitting at the anion exchange membrane during electrodialytic remediation of contaminated harbor sediment and hence the metal removal, was influenced by different experimental conditions. Two different experimental cells were tested, where the number of compartments and ion exchange membranes differed. Totally, 14 electrodialytic experiments were made, with varying remediation time, current densities, and liquid to solid ratio (L/S). pH in the sediment decreased slightly after 1 day of remediation, even if the sediment had a high buffering capacity, suggesting that water splitting at the anion exchange membrane started early in the remediation process. An increase in the voltage over the cell and a decrease in the electrical conductivity in the sediment suspension also indicated that the water splitting started within 1 day of remediation. When the sediment was acidified, the voltage decreased and electrical conductivity increased. After 5 days of remediation the sediment was acidified at the chosen current density (1 mA/cm(2)) and the main metal removal was observed shortly after. Thus it was crucial for the metal removal that the sediment was fully acidified. Lower metal removal was seen in an experimental cell with three compartments compared to five compartments, due to increased sensitivity of pH changes in the cell.

NystrØm, Gunvor Marie; Ottosen, Lisbeth M.

2005-01-01

 
 
 
 
81

On the use of biosurfactants for the removal of heavy metals from oil-contaminated soil  

Energy Technology Data Exchange (ETDEWEB)

The feasibility of using biodegradable biosurfactants to remove heavy metals from an oil-contaminated soil was evaluated by batch washes with surfactin, a rhamnolipid and a sophorolipid. The soil contained 890 mg/kg of zinc and 420 mg/kg of copper with a 12.6% oil and grease content. Highest levels of zinc removal were obtained using 12% rhamnolipid and 4% sophorolipid/0.7% HCl. Highest copper removal rates were achieved with 12% rhamnolipid or with 2% rhamnolipid/1% NaOH or 0.25% surfactin/1% NaOH. A series of five batch washes removed 70% of the copper with 0.1% surfactin/1% NaOH while 4% sophorolipid/0.7% HCl was able to remove 100% of the zinc. Sequential extraction procedures showed that the carbonate and oxide fractions accounted for over 90% of the zinc present in the soil and the organic fraction in the soil constituted over 70% of the copper. Sequential extraction of the soil after washing with the surfactin or rhamnolipid indicated that these surfactants could remove the organically-bound copper and that the sophorolipid with acid could remove the carbonate and oxide-bound zinc. In conclusion, the results clearly indicated the feasibility of removing the metals with the anionic biosurfactants tested even though the exchangeable metal fractions were very low.

Mulligan, C.N. [Concordia Univ., Montreal, Quebec (Canada). Dept. of Building, Civil and Environmental Engineering; Yong, R.N. [Univ. of Wales, Cardiff (United Kingdom); Gibbs, B.F. [Bivan Consultants Inc., Montreal, Quebec (Canada). Environmental Div.

1999-05-01

82

Characterization of natural adsorbent material for heavy metal removal in a petrochemical site contamination  

Directory of Open Access Journals (Sweden)

Full Text Available Despite of over 25 years of intensive technological efforts, sub-surface environment cleanup still remains a challenge, especially in case of highly contaminated sites. In this context, ion exchanger technologies could provide simple and effective solutions for heavy metal removal in water treatment. The challenge is finding exchanger able to operate in extreme natural environments or in situations involving natural interfering species such as inorganic ions. In this paper we exam the use of natural zeolites as versatile exchanger for environmental protection of coastal refinery's groundwater against pollution of Ni, Cd, Pb. The influence of particle diameter on clinoptilolite performances toward heavy metal removal is studied. Also, we evaluate the exchanger activities in condition of high ionic strength, commonly present in groundwater located under coastal petrol industries. The obtained results confirmed that ion exchangers could provide an effective solutions for remediation in complex environmental conditions.

Bianchi F.; Farao C.; Maretto M.; Petrangeli Papini M.; Vignola R.

2013-01-01

83

Synthesis of LTA zeolite on corundum supports: Preliminary assessment for heavy metal removal from waste water  

International Nuclear Information System (INIS)

[en] The effectiveness of materials based on LTA Zeolite as active phase, for their incorporation into systems aimed at the removal of heavy metals on waste water is evaluated in a preliminary way. This type of Zeolite with the main channel of a minimum free diameter of 0,41 nm and a low SiO2/Al2O3 ratio is an interesting molecular sieve, which in turn display a high ion exchange capacity. From this point of view, LTA Zeolite crystals were obtained in situ by hydrothermal synthesis and characterized by x ray diffraction (XRD) and scanning electron microscopy (SEM). We have studied the effect of hydrothermal synthesis time at 378 K. Likewise, the removal capacity of heavy metal from the active phase was evaluated in as a first step on diluted solutions of cooper salts at slightly acidic pH (? 4,7). (Author) 28 refs.

2012-01-01

84

Removal of radioactive materials and heavy metals from water using magnetic resin  

Energy Technology Data Exchange (ETDEWEB)

Magnetic polymer resins capable of efficient removal of actinides and heavy metals from contaminated water are disclosed together with methods for making, using, and regenerating them. The resins comprise polyamine-epichlorohydrin resin beads with ferrites attached to the surfaces of the beads. Markedly improved water decontamination is demonstrated using these magnetic polymer resins of the invention in the presence of a magnetic field, as compared with water decontamination methods employing ordinary ion exchange resins or ferrites taken separately.

Kochen, Robert L. (Boulder, CO); Navratil, James D. (Simi Valley, CA)

1997-01-21

85

Removal of radioactive materials and heavy metals from water using magnetic resin  

International Nuclear Information System (INIS)

Magnetic polymer resins capable of efficient removal of actinides and heavy metals from contaminated water are disclosed together with methods for making, using, and regenerating them. The resins comprise polyamine-epichlorohydrin resin beads with ferrites attached to the surfaces of the beads. Markedly improved water decontamination is demonstrated using these magnetic polymer resins of the invention in the presence of a magnetic field, as compared with water decontamination methods employing ordinary ion exchange resins or ferrites taken separately. 9 figs.

1993-05-07

86

Removal of heavy metal ions from oil shale beneficiation process water by ferrite process  

Energy Technology Data Exchange (ETDEWEB)

The ferrite process is an established technique for removing heavy metals from waste water. Because the process water resulting from oil shale beneficiation falls into the category of industrial waste water, it is anticipated that this process may turn out to be a potential viable treatment for oil shale beneficiation process water containing many heave metal ions. The process is chemoremedial because not only effluent water comply with quality standards, but harmful heavy metals are converted into a valuable, chemically stable by-product known as ferrite. These spinel ferrites have magnetic properties, and therefore can be use in applications such as magnetic marker, ferrofluid, microwave absorbing and scavenging material. Experimental results from this process are presented along with results of treatment technique such as sulfide precipitation.

Mehta, R.K.; Zhang, L.; Lamont, W.E.; Schultz, C.W. [Alabama Univ., University, AL (United States). Mineral Resources Inst.

1991-12-31

87

Removal of heavy metal ions from oil shale beneficiation process water by ferrite process  

Energy Technology Data Exchange (ETDEWEB)

The ferrite process is an established technique for removing heavy metals from waste water. Because the process water resulting from oil shale beneficiation falls into the category of industrial waste water, it is anticipated that this process may turn out to be a potential viable treatment for oil shale beneficiation process water containing many heave metal ions. The process is chemoremedial because not only effluent water comply with quality standards, but harmful heavy metals are converted into a valuable, chemically stable by-product known as ferrite. These spinel ferrites have magnetic properties, and therefore can be use in applications such as magnetic marker, ferrofluid, microwave absorbing and scavenging material. Experimental results from this process are presented along with results of treatment technique such as sulfide precipitation.

Mehta, R.K.; Zhang, L.; Lamont, W.E.; Schultz, C.W. (Alabama Univ., University, AL (United States). Mineral Resources Inst.)

1991-01-01

88

Quantum dot impregnated-chitosan film for heavy metal ion sensing and removal.  

UK PubMed Central (United Kingdom)

We report the use of biopolymer-stabilized ZnS quantum dots (Q-dots) for cation exchange reaction-based easy sensing and removal of heavy metal ions such as Hg(2+), Ag(+), and Pb(2+) in water. Chitosan-stabilized ZnS Q-dots were synthesized in aqueous medium and were observed to have been converted to HgS, Ag(2)S, and PbS Q-dots in the presence of corresponding ions. The transformed Q-dots showed characteristic color development, with Hg(2+) being exceptionally identifiable due to the visible bright yellow color formation, while brown coloration was observed in other metal ions. The cation exchange was driven by the difference in the solubility product of the reactant and the product Q-dots. The cation exchanged Q-dots preserved the morphology of the reactant Q-dots and displayed volume increase based on the bulk crystal lattice parameters. The band gap of the transformed Q-dots showed a major increase from the corresponding bulk band gap of the material, demonstrating the role of quantum confinement. Next, we fabricated ZnS Q-dot impregnated chitosan film which was used to remove heavy metal ions from contaminated water as measured using atomic absorption spectroscopy (AAS). The present system could suitably be used as a simple dipstick for elimination of heavy metal ion contamination in water.

Jaiswal A; Ghsoh SS; Chattopadhyay A

2012-11-01

89

Quantum dot impregnated-chitosan film for heavy metal ion sensing and removal.  

Science.gov (United States)

We report the use of biopolymer-stabilized ZnS quantum dots (Q-dots) for cation exchange reaction-based easy sensing and removal of heavy metal ions such as Hg(2+), Ag(+), and Pb(2+) in water. Chitosan-stabilized ZnS Q-dots were synthesized in aqueous medium and were observed to have been converted to HgS, Ag(2)S, and PbS Q-dots in the presence of corresponding ions. The transformed Q-dots showed characteristic color development, with Hg(2+) being exceptionally identifiable due to the visible bright yellow color formation, while brown coloration was observed in other metal ions. The cation exchange was driven by the difference in the solubility product of the reactant and the product Q-dots. The cation exchanged Q-dots preserved the morphology of the reactant Q-dots and displayed volume increase based on the bulk crystal lattice parameters. The band gap of the transformed Q-dots showed a major increase from the corresponding bulk band gap of the material, demonstrating the role of quantum confinement. Next, we fabricated ZnS Q-dot impregnated chitosan film which was used to remove heavy metal ions from contaminated water as measured using atomic absorption spectroscopy (AAS). The present system could suitably be used as a simple dipstick for elimination of heavy metal ion contamination in water. PMID:23020689

Jaiswal, Amit; Ghsoh, Siddhartha Sankar; Chattopadhyay, Arun

2012-10-22

90

Preparation and Characterization of Ceramic Hollow Microspheres for Heavy Metal Ion Removal in Wastewater.  

UK PubMed Central (United Kingdom)

Ceramic hollow microspheres (CHMSs) were prepared to use as supports for the removal of heavy metal ions from industrial waste-water. A water extraction sol-gel technique was used to prepare porous CHMS by extracting water from an emulsion of LUDOX (silica colloid; SiO(2), Aldrich Co.) and 2-ethyl-1-hexanol. Experiments were conducted to control pore size, wall thickness, and separation yield by examining the ratio of precursors (LUDOX and 2-ethyl-1-hexanol), catalyst (NH(4)OH), sintering temperature, surfactant (SPAN 80), extractant (n-butanol), stirring speed, and concentration of precursor (LUDOX). The results revealed that the optimum conditions were 20 ml of a 10 wt% solution of LUDOX, 10 ml of NH(4)OH, a sintering temperature of 500 degrees C, 0.4 ml of SPAN 80, 200 ml of n-butanol, and a stirring speed of 730 rpm/100 ml of 2-ethyl-1-hexanol. CHMSs were impregnated in Cyanex 272 and examined for their ability to remove heavy metal ions from a solution. Based on an experiment involving the removal of metal ions using CHMSs that were prepared under optimum conditions, Zn ion was removed at a level of 0.354 mmol/g at pH 4, which was about twice the adsorption capacity of CHMSs prepared by Wilcox (Mater. Res. Soc. Symp. Proc. 346, 201 (1994)). Copyright 2000 Academic Press.

Bae E; Chah S; Yi J

2000-10-01

91

Preparation and Characterization of Ceramic Hollow Microspheres for Heavy Metal Ion Removal in Wastewater.  

Science.gov (United States)

Ceramic hollow microspheres (CHMSs) were prepared to use as supports for the removal of heavy metal ions from industrial waste-water. A water extraction sol-gel technique was used to prepare porous CHMS by extracting water from an emulsion of LUDOX (silica colloid; SiO(2), Aldrich Co.) and 2-ethyl-1-hexanol. Experiments were conducted to control pore size, wall thickness, and separation yield by examining the ratio of precursors (LUDOX and 2-ethyl-1-hexanol), catalyst (NH(4)OH), sintering temperature, surfactant (SPAN 80), extractant (n-butanol), stirring speed, and concentration of precursor (LUDOX). The results revealed that the optimum conditions were 20 ml of a 10 wt% solution of LUDOX, 10 ml of NH(4)OH, a sintering temperature of 500 degrees C, 0.4 ml of SPAN 80, 200 ml of n-butanol, and a stirring speed of 730 rpm/100 ml of 2-ethyl-1-hexanol. CHMSs were impregnated in Cyanex 272 and examined for their ability to remove heavy metal ions from a solution. Based on an experiment involving the removal of metal ions using CHMSs that were prepared under optimum conditions, Zn ion was removed at a level of 0.354 mmol/g at pH 4, which was about twice the adsorption capacity of CHMSs prepared by Wilcox (Mater. Res. Soc. Symp. Proc. 346, 201 (1994)). Copyright 2000 Academic Press. PMID:11017745

Bae; Chah; Yi

2000-10-15

92

Removal of Some Heavy Metals from Wastewater using Radiation- Adsorption Method  

International Nuclear Information System (INIS)

[en] Wastewater containing toxic materials poses a serious environmental problem. Many of the pollutants are not readily biodegradable and complete removal in many cases is a relatively expensive process. On the other hand, incomplete removal is a serious health hazard. In the present study, a try was made to explain the degradation kinetics due to gamma-irradiation and adsorption of some heavy metals: Uranium, Molybdenum, Zirconium, and Vanadium. Factors affecting the process such as concentration, irradiation dose and ph of the solution was studied. Gamma-radiation doses up to 50 kGy did not result in the degradation of the heavy metals. However, as expected gamma radiation resulted in a change in the valency of these heavy metal ions to other oxidation states which may have resulted in less toxicity. Adsorption and ion-exchange purification of the heavy metals onto GAC,Merck Ion Exchangers I, and IV and polymeric membranes showed that GAC has the highest adsorption capacity for all pollutants compared with the ion-exchangers and polymeric membranes which may be due to its very high surface area and high porous nature which causes internal and external distribution within the carbon particle more than it dose in the case of polymeric membranes and ion-exchangers. GAC was followed by the cation exchanger with different percent adsorption according to the type of pollutant and the least removal percent was shown by the polymeric membranes. Also, a study of the affinity of the pollutants towards the different adsorbents was carried out

2000-01-01

93

Removal of heavy metals from wastewater using steelmaking slag and sludge  

Energy Technology Data Exchange (ETDEWEB)

This study was carried out to investigate the efficiency of steelmaking slag and sludge in removing metals existing in wastewater or leachate. Laboratory experiments were performed as a function of initial concentration of metals, pH and temperature of the background solution and the presence of chelating agent, EDTA. The test conditions were temperatures ranging from 25 deg.C to 50 deg.C; initial concentrations varying from 5 mg/L to 50 mg/L; pH between 3 and 11; and Cu, Cd, and Pb is adsorbates. The results of tests showed that overall rates of metals removal were 20-30% at pH 3 and greater than 90% at pH 7 and 11. Metals were removed from the solution predominantly via adsorption in acidic conditions, and the combined effects of adsorption and precipitation in neutral and alkaline conditions. In view of the test results and other engineering characteristics of steelmaking slag and sludge, these industrial by-products from steel industry have a high potential to be used in wastewater treatment and are particularly beneficial when used as landfill liner additives due to their ability to remove heavy metals from leachate. (author). 17 refs., 7 tabs., 5 figs.

Hyun, Jae-Hyuk; Kim, Min-Gil; Nam, In-Young; Baek, Jung-Sun [Chungnam National University, Taejon (Korea)

1999-03-31

94

Polyaza macroligands as potential agents for heavy metal removal from wastewater  

Directory of Open Access Journals (Sweden)

Full Text Available Two polyaza macroligands N,N´-bis(2-aminobenzyl)-1,2- ethanediamine (L1) and 3,6,9,12-tetraaza-4(1,2),11(1,2)-dibenzo-1(1,3)- piridinaciclotridecafano (L2) were characterized and investigated for their metal ion extraction capabilities. The nature of all complexes was established by spectroscopic techniques. The equilibrium constants were determined by spectrophotometric and potentiometric techniques and the residual concentration of metals in the solutions by Atomic Absorption Spectrometry (AAS). The capacity of the ligands to remove heavy metals such as Cu(II), Ni(II), Cd(II), Zn(II) and Pb(II) as insoluble complexes was evaluated in wastewater from industrial effluents. These agents showed high affinity for the studied metals. The values of equilibrium constants of the isolated complexes (between 1 x 104 and 2 x 107) demonstrated the feasibility of applying these chelating agents as an alternative to remove heavy metals from industrial effluents.

Elizondo Martínez Perla; Nájera Martínez Blanca; Pérez Rodríguez Nancy; Reyes Hinojosa Laura; Río Del Gómez Isabel Ma

2013-01-01

95

Innovative use of activated carbon for the removal of heavy metals from ground water sources  

Energy Technology Data Exchange (ETDEWEB)

This report discusses the evaluation of the ENVIRO-CLEAN PROCESS, a technology developed by Lewis Environmental Services, Inc. for the recovery of metals such as chromium, mercury, copper, cadmium, lead, and zinc from surface and groundwater streams. This new heavy metal removal process (patent-pending) utilizes granular activated carbon with a proprietary conditioning pretreatment to enhance heavy metal adsorption combined with electrolytic metal recovery to produce a saleable metallic product. The process generates no sludge or hazardous waste and the effluent meets EPA limits. A 50 gpm system was installed for recovering hexavalent chromium from a ground water stream at a site located in Fresno, California. The effluent from the activated carbon system was reinjected into the ground water table with the hexavalent chromium concentration < 10 ppb. The system simultaneously removed trichloroethylene (TCE) to concentrations levels < 05 ppb. The activated carbon is regenerated off-site and the chromium electrolytically recovered. The full scale system has treated over 5 million gallons of ground water since installation. 5 refs., 1 fig., 3 tabs.

Lewis, T. III [Lewis Environmental Services, Inc., Pittsburgh, PA (United States)

1996-12-31

96

Heavy metal removal from sewage sludge ash by thermochemical treatment with polyvinylchloride.  

UK PubMed Central (United Kingdom)

Sewage sludge ash (SSA) is a prospective phosphorus source for the future production of recycling P-fertilizers. Due to its high heavy metals contents and the relatively low P plant-availability, SSA must be treated before agricultural utilisation. In this paper SSA was thermochemically treated with PVC in a bench-scale rotary furnace in order to remove heavy metals via the chloride pathway. PVC has a high Cl-content of 52-53% and a high heating value that can be beneficially used for the thermochemical process. Large amounts of waste PVC are already recovered in recycling processes, but there are still some fractions that would be available for the proposed thermochemical process, for example, the low quality near-infrared(NIR)-fraction from waste separation facilities. Heavy metals were effectively removed at temperatures in the range of 800-950 °C via the gas phase by utilisation of PVC as Cl-donor. The resulting P plant-availability was comparable to SSA thermochemically treated with MgCl(2) as Cl-donor if MgO was used as an additive (Mg-donor). A further increase of the plant availability of phosphorus was achieved by acid post-treatment of the thermochemically treated SSA.

Vogel C; Exner RM; Adam C

2013-01-01

97

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

UK PubMed Central (United Kingdom)

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

Tang WW; Zeng GM; Gong JL; Liang J; Xu P; Zhang C; Huang BB

2013-10-01

98

Heavy metal removal from synthetics wastes by natural and acid-activated bentonite s  

International Nuclear Information System (INIS)

This paper examines heavy metals removal from synthetics wastes by the use of natural and sulfuric acid-activated bentonite so that a cheap adsorbent can be attained for removing these metals from the wastes. Bentonite is a 2: 1 layer alurninnisilicate whose dominant mineral is montmorillonite which is a nano-structure and nano porous material. Montmorillonite affects all the properties of bentonite. In the next step, the effect of acid activation on the adsorption of both of lead (Pb) and thallium (Tl) is studied. In this research, after the mineralogical and chemical composition analyses by X-ray diffraction and fluorescence (XRD and X-ray fluorescence) methods, granulometric analysis is carried out on five samples namely, S 2-Raw, S 3-Raw, Es 3-Raw, G 1-Raw and GH 1-Raw to remove the heavy metals such as Cr, Co, Cu, Fe, Pb, Tl, Ni, and Zn accompanying atomic absorption spectroscopy. Then, the effect of four factors including concentration, liquid to solid ratio (L/S), time, and activation temperature in acid activation process were studied. This process is done by a mineral acid, sulfuric acid, to promote the absorbability of lead and thallium in both natural and activated types of Es 3-Raw and GH 1-Raw. In all case, due to the presence of dominant mineral of nano-montmorillonite and its unique structure, montmorillonite has a higher absorbability in comparison with that of the other clay minerals.

2010-01-01

99

Comparison of the heavy metal removal efficiency of biosorbents and granular activated carbons  

Energy Technology Data Exchange (ETDEWEB)

The adsorption efficiencies of granular carbon (GAC) and biosorbents: Saccaromyces cerevisiae yeast (caustic treated and active) immobilized in GAC; yeast (caustic treated) immobilized in alginate acid, and alginate itself were compared for the removal of Cu{sup 2+}, Cd{sup 2+}, Zn{sup 2+} from simulated waste waters. Yeast biomass has a high capacity for uptake of heavy metal ions, and can be adsorbed on activated carbon. The alginate used in this study was used as an entrapment material to immobilize yeast. It was observed that the pH of the solution was a critical parameter for the adsorption process; the value chosen in the experiments was 4.5. Two different experimental modes were used, a batch mode and a flow mode were used. In batch mode operation, using biosorbents yeast immobilized on GAC and on alginate, the percentage removal of heavy metal can exceed 90%. When only GAC was used as an adsorbent, acceptable results were obtained. Comparing the two different experimental modes, no difference was observed in the percentage removal of metal ions, although a longer time was needed for the flow system to reach adsorption equilibrium compared to batch mode. 32 refs., 5 figs., 4 tabs.

Wilkins, E.; Yang, Q. [Univ. of New Mexico, Albuquerque, NM (United States)

1996-10-01

100

Removal of Heavy Metals from Industrial Wastewaters Using Local Alum and Other Conventional Coagulants-A Comparative Study  

Directory of Open Access Journals (Sweden)

Full Text Available The present study aimed at effective management and purification of industrial wastewaters using cheaper and locally available local alum for removal of heavy metals as a substitute to convectional coagulants. The effect of local alum, aluminum sulphate and ferric chloride on the metal contents of industrial wastewaters was investigated in the pH range of 5.9-7.5. Wastewater samples from battery, paint and textile industries were treated with different doses of locally available alum, aluminum sulphate and ferric chloride in order to determine and compare their effectiveness in removing heavy metal contents of the wastewaters. The percentage removal of the metals from the industrial wastewaters increased with mg L-l dosage of the coagulants used with optimal performance generally at a slightly alkaline pH. Local alum proved to be equally effective in removing heavy metals from the industrial wastewater samples compared with the conventional aluminum sulphate and ferric chloride.

A.O. Ogunfowokan; L.M. Durosinmi; J.A.O. Oyekunle; O.A. Ogunkunle; I.T. Igbafe

2007-01-01

 
 
 
 
101

Montmorillonite surface properties and sorption characteristics for heavy metal removal from aqueous solutions  

International Nuclear Information System (INIS)

Surface properties of montmorillonite (MMT) and its adsorption characteristics for heavy metals have been investigated with nickel and copper as sorbate from aqueous solutions. Employing the potentiometric and mass titration techniques in batch experimental methods, the point of zero charge (PZC) and point of zero net proton charge (PZNPC) of MMT edges at different ionic strengths present pHPZC and pHPZNPC to be 3.4 ± 0.2. A crossing point was observed for the proton adsorption vs. pH curves at different ionic strengths of KCl electrolyte and in investigating MMT remediation potentialities as sorbent for heavy metals polluted waters, the effects of heavy metal concentration, pH, MMT dosage, reaction time and temperature for Cu2+ and Ni2+ uptake were studied. The sorption of metal ions by MMT was pH dependent and the adsorption kinetics revealed sorption rate could be well fitted by the pseudo-second-order rate model. The data according to mass transfer and intraparticle diffusion models confirmed diffusion of solutes inside the clay particles as the rate-controlling step and more important for the adsorption rate than the external mass transfer. Adsorption isotherms showed that the uptake of Cu2+ and Ni2+ could be described by the Langmuir model and from calculations on thermodynamic parameters, the positive ?Go values at different temperatures suggest that the sorption of both metal ions were non-spontaneous. Change in enthalpy (?Ho) for Ni2+ and Cu2+ were 28.9 and 13.27 kJ/mol K respectively, hence an endothermic diffusion process, as ion uptake increased with increase in temperature. Values of ?So indicate low randomness at the solid/solution interface during the uptake of both Cu2+ and Ni2+ by MMT. Montmorillonite has a considerable potential for the removal of heavy metal cationic species from aqueous solution and wastewater.

2009-07-15

102

Metal biosorption capability of Cupriavidus taiwanensis and its effects on heavy metal removal by nodulated Mimosa pudica.  

Science.gov (United States)

A novel metal biosorption system consisting of the symbiotic combination of an indigenous metal-resistant rhizobial strain, Cupriavidus taiwanensis TJ208, and its host plant Mimosa pudica has been developed for the removal of heavy-metal pollutants. Free-living C. taiwanensis TJ208 cells were able to adsorb 50.1, 19.0, and 19.6 mg/g of Pb, Cu, and Cd, respectively. After nodulation via inoculation with strain TJ208, the metal uptake ability of M. pudica markedly increased, as the nodulated M. pudica displayed a high metal uptake capacity (qmax) of 485, 25, and 43 mg/g, respectively, which is 86, 12, and 70% higher than that of nodule-free plants. Moreover, with TJ208 nodules, the M. pudica plant also displayed a 71, 81, and 33% enhancement in metal adsorption efficiency (eta) for Pb, Cu, and Cd, respectively. The nodulation appeared to give the greatest enhancing effect on the uptake of Pb, which is consistent with the preference of metal adsorption ability of TJ208. This seems to indicate the crucial role that the rhizobial strain may play in stimulating metal uptake of the nodulated plant. Furthermore, the results show that metal accumulation in the nodulated plant mainly occurred in the roots, accounting for 65-95% of total metal uptake. In contrast, the nodules and the shoots only contributed to 3-12 and 2-23% of total metal uptake, respectively. Nevertheless, the specific adsorption capacity of nodules is comparable to that of the roots. Hence, this work demonstrates the feasibility and effectiveness of using the nodulated plants to promote phyto-removal of heavy metals from the polluted environment as well as to restrict the metal contaminants in the unharmful region of the plant. PMID:17624667

Chen, Wen-Ming; Wu, Chih-Hui; James, Euan K; Chang, Jo-Shu

2007-06-02

103

Heavy metal removal in an UASB-CW system treating municipal wastewater.  

UK PubMed Central (United Kingdom)

The objective of the present study was to investigate for the first time the long-term removal of heavy metals (HMs) in a combined UASB-CW system treating municipal wastewater. The research was carried out in a field pilot plant constituted for an up-flow anaerobic sludge bed (UASB) digester as a pretreatment, followed by a surface flow constructed wetland (CW) and finally by a subsurface flow CW. While the UASB showed (pseudo) steady state operational conditions and generated a periodical purge of sludge, CWs were characterised by the progressive accumulation and mineralisation of retained solids. This paper analyses the evolution of HM removal from the water stream over time (over a period of 4.7year of operation) and the accumulation of HMs in UASB sludge and CW sediments at two horizons of 2.7 and 4.0year of operation. High removal efficiencies were found for some metals in the following order: Sn>Cr>Cu>Pb>Zn>Fe (63-94%). Medium removal efficiencies were registered for Ni (49%), Hg (42%), and Ag (40%), and finally Mn and As showed negative percentage removals. Removal efficiencies of total HMs were higher in UASB and SF units and lower in the last SSF unit.

de la Varga D; Díaz MA; Ruiz I; Soto M

2013-08-01

104

Simultaneous removal of heavy metal ions from wastewater by foam separation techniques  

Energy Technology Data Exchange (ETDEWEB)

The objective of the present work is to extend the application of adsorbing colloid flotation techniques to remove mixtures of metal ions. The systems studied are: 1) Co(II) and Cr(VI); 2) Co(II), Ni(II), and Cr(VI); 3) Cr(VI), Cu(II), and Zn(II); 4) Cr(VI), Cu(II), Zn(II), and Ni(II); 5) Cd(II), Pd(II), and Cu(II). Ferric hydroxide and aluminum hydroxide were used as the coprecipitant, and sodium lauryl sulfate was used as the collector and frother. The ionic strength of the solution was adjusted with NaNO/sub 3/ or Na/sub 2/SO/sub 4/. It was found that all the heavy metals can be removed effectively by a single step foam flotation treatment.

Huang, S.D.; Huang, M.K.; Gua, J.Y.; Wu, T.P.; Huang, J.Y.

1988-04-01

105

Electrochemical iron generation: The ideal process for simultaneous removal of heavy metals from contaminated groundwater  

Energy Technology Data Exchange (ETDEWEB)

At most Superfund sites, many heavy metals must be removed from contaminated groundwater. Simultaneous extraction is complicated due to the various chemical properties that metals exhibit. A comprehensive understanding of solubilities, oxidation states, and adsorptive mechanisms is needed to accomplish treatment objectives. This paper uses data from treatability tests conducted on groundwater from the King of Prussia Technical Corporation Site to discuss the electrochemical iron generation process developed by Andco Environmental Processes, Inc. Electrical current and sacrificial steel electrodes were used to put ferrous ions into solution. The chemistry was properly manipulated to provide adsorption and coprecipitation conditions capable of simultaneously removing beryllium, cadmium, chromium, copper, iron, manganese, mercury, nickel, and zinc. Strict cleanup levels were required since the site is located within Pinelands National Reserve and adjacent to New Jersey`s Winslow Wildlife Refuge. System design, operating costs, and sludge production rate are also discussed.

Brewster, M.D. [Andco Environmental Processes, Inc., Buffalo, NY (United States)

1993-12-31

106

Untreated coffee husks as biosorbents for the removal of heavy metals from aqueous solutions.  

UK PubMed Central (United Kingdom)

The objective of this work was to propose an alternative use for coffee husks (CH), a coffee processing residue, as untreated sorbents for the removal of heavy metal ions from aqueous solutions. Biosorption studies were conducted in a batch system as a function of contact time, initial metal ion concentration, biosorbent concentration and pH of the solution. A contact time of 72 h assured attainment of equilibrium for Cu(II), Cd(II) and Zn(II). The sorption efficiency after equilibrium was higher for Cu(II) (89-98% adsorption), followed by Cd(II) (65-85%) and Zn(II) (48-79%). Even though equilibrium was not attained in the case of Cr(VI) ions, sorption efficiency ranged from 79 to 86%. Sorption performance improved as metal ions concentrations were lowered. The experimental sorption equilibrium data were fitted by both Langmuir and Freundlich sorption models, with Langmuir providing the best fit (R2>0.95). The biosorption kinetics was determined by fitting first and second-order kinetic models to the experimental data, being better described by the pseudo-second-order model (R2>0.99). The amount of metal ions sorbed increased with the biosorbent concentration in the case of Cu(II) and Cr(VI) and did not present significant variations for the other metal ions. The effect of the initial pH in the biosorption efficiency was verified in the pH range of 4-7, and the results showed that the highest adsorption capacity occurred at distinct pH values for each metal ion. A comparison of the maximum sorption capacity of several untreated biomaterial-based residues showed that coffee husks are suitable candidates for use as biosorbents in the removal of heavy metals from aqueous solutions.

Oliveira WE; Franca AS; Oliveira LS; Rocha SD

2008-04-01

107

Removal of heavy metals using a microbial active, continuously operated sand filter  

International Nuclear Information System (INIS)

Heavy metals play an important role within the spectrum of the various pollutants, emitted into the environment via human activities. In contrast to most organic pollutants, heavy metal can not be degraded. Many soils, lakes and rivers show a high contamination with heavy metals due to the enrichment of these pollutants. In addition to existing chemical-physical and biological technologies for the treatment of heavy metal containing waste waters a demand for new, efficient and low-cost cleaning technologies exists, particularly for high volumes of weakly contaminated waters. Such a technology was developed within the framework of a scientific project of the European Union. The approach makes use of a continuously operated, moving-bed Astrasand filter, which has been operated as a continuous biofilm reactor. By inoculation of the reactor with bacteria providing different, defined mechanisms of metal immobilization, and by continuous supply of suitable nutrients, a metal-immobilizing biofilm is built up and regenerated continuously. Metal-enriched biomass is removed continuously from the system, and the contained metals can be recycled by pyrometallurgical treatment of the biomass. The subjects of the present work were the optimization of the nutrient supply for the process of metal removal, the investigation of the toxicity of different waste waters, the optimization of inoculation and biofilm formation, set-up and operation of a lab scale sand filter and the operation of a pilot scale sand filter treating rinsing water of a chemical nickel plating plant. First, basic parameters like toxicity of heavy metal-containing waste waters and the influence of the nutrition of bacteria on biosorption and total metal removal were examined, using freely suspended bacteria in batch culture. Concerning toxicity great differences could be found within the spectrum of heavy metal-containing waste waters tested. Some waters completely inhibited growth, while others did not influence the bacterial biomass production. A sand column system with partial circulation of the waste water was constructed for the treatment of toxic waste waters. Using this experimental set-up a resistant biofilm was built up by continuous increase of waste water concentration. With this biofilm-system it is possible to treat waste waters, which completely inhibit bacterial growth with freely suspended cells in batch culture. The selection of suitable nutrients for the bacteria turned out to be crucial for the efficiency of the metal removal process too. From all essential macro- and micro-elements only C, N and P had to be added to the waste waters, in some cases the addition of a carbon source was sufficient. All other nutrients were already present in the waste waters. In order to optimize the nutrient supplementation, various carbon and nitrogen sources were checked concerning biomass production and metal removal. Some nutrient sources strongly supported bacterial growth, but simultaneously reduced metal removal by unfavorable chemical interactions with heavy metals. From all nutrient sources tested, Na-acetate turned out to be the best choice for carbon supply of the bacteria. If the addition of nitrogen to the waste water is necessary, nitrate, ammonia or urea are suitable sources for bacterial growth and metal removal. In experiments with single fixed bed columns (100 cm3 sand) and subsequent tests in the lab-scale (10 dm3 sand) and pilot scale sand filter (1,7 m3 sand), a suitable procedure for the inoculation of the sand filter and the formation of biofilm on the sand grains was developed. The maintenance of stock cultures was carried out on agar plates made of waste water, enriched with missing nutrients. Production of the biomass for inoculation was realized in liquid culture using waste water, enriched with nutrients too. The formation of a biofilm on the sand grains was achieved by addition of the liquid culture to the sand filter, supply of nutrients and distribution of the formed biomass by internal circulation through the airlift. Concerning the pro

2001-01-01

108

Heavy-metal removal from petroleum oily sludge using lemon- scented geraniums[General Conference  

Energy Technology Data Exchange (ETDEWEB)

Finding an acceptable method to manage oily sludge generated during petroleum processes is one of the challenges currently facing the petroleum industry. This study investigated the response of plants to heavy-metal removal from oily sludge to determine the feasibility of using phytoremediation technologies as a treatment method for oily sludge. In particular, scented geraniums (Pelargonium sp. Frensham) have shown a strong capability to survive harsh conditions such as poor soil, high/low temperatures, high heavy-metal concentrations and low water content. In response to this observation, this feasibility study placed scented geraniums in a series of pots containing oily sludge where heavy-metal concentrations were artificially increased up to 2000 ppm. Plants were grown in two systems over a period of 50 days. The first system included oily sludge and soil while the second system included oily sludge, soil and compost. The study revealed that the scented geraniums accumulated up to 1600 mg, 1000 mg, and 1200 mg, of cadmium, nickel and vanadium respectively per 1 kg of the plant's dry weight. The results suggest that phytoremediation technology may be a potential method for successfully treating or pretreating oily sludge in the field.

Badawieh, A.; Elektorowicz, M. [Concordia Univ., Montreal, PQ (Canada). Dept. of Building, Civil and Environmental Engineering

2006-07-01

109

Effect of large pore size of multifunctional mesoporous microsphere on removal of heavy metal ions.  

UK PubMed Central (United Kingdom)

Pore size of mesoporous materials is crucial for their surface grafting. This article develops a novel multifunctional microsphere with a large pore size mesoporous silica shell (ca. 10.3 nm) and a magnetic core (Fe?O?), which is fabricated using cetyltrimethylammonium bromide (CTAB) as pore-forming agents, tetraethyl orthosilicate (TEOS) as silicon source through a sol-gel process. Compared with small pore size mesoporous silica magnetic microspheres (ca. 2-4 nm), the large pore size one can graft 447 mg/g amino groups in order to adsorb more heavy metal ions (Pb(2+): 880.6 mg/g, Cu(2+): 628.3mg/g, Cd(2+): 492.4 mg/g). The metal-loaded multifunctional microspheres could be easily removed from aqueous solution by magnetic separation and regenerated easily by acid treatment. The results suggest that the large pore size multifunctional microspheres are potentially useful materials for high effectively adsorbing and removing different heavy metal ions in aqueous solution.

Yuan Q; Li N; Chi Y; Geng W; Yan W; Zhao Y; Li X; Dong B

2013-06-01

110

Effect of large pore size of multifunctional mesoporous microsphere on removal of heavy metal ions.  

Science.gov (United States)

Pore size of mesoporous materials is crucial for their surface grafting. This article develops a novel multifunctional microsphere with a large pore size mesoporous silica shell (ca. 10.3 nm) and a magnetic core (Fe?O?), which is fabricated using cetyltrimethylammonium bromide (CTAB) as pore-forming agents, tetraethyl orthosilicate (TEOS) as silicon source through a sol-gel process. Compared with small pore size mesoporous silica magnetic microspheres (ca. 2-4 nm), the large pore size one can graft 447 mg/g amino groups in order to adsorb more heavy metal ions (Pb(2+): 880.6 mg/g, Cu(2+): 628.3mg/g, Cd(2+): 492.4 mg/g). The metal-loaded multifunctional microspheres could be easily removed from aqueous solution by magnetic separation and regenerated easily by acid treatment. The results suggest that the large pore size multifunctional microspheres are potentially useful materials for high effectively adsorbing and removing different heavy metal ions in aqueous solution. PMID:23618656

Yuan, Qing; Li, Nan; Chi, Yue; Geng, Wangchang; Yan, Wenfu; Zhao, Ying; Li, Xiaotian; Dong, Bin

2013-03-22

111

Separation of heavy metals: Removal from industrial wastewaters and contaminated soil  

Energy Technology Data Exchange (ETDEWEB)

This paper reviews the applicable separation technologies relating to removal of heavy metals from solution and from soils in order to present the state-of-the-art in the field. Each technology is briefly described and typical operating conditions and technology performance are presented. Technologies described include chemical precipitation (including hydroxide, carbonate, or sulfide reagents), coagulation/flocculation, ion exchange, solvent extraction, extraction with chelating agents, complexation, electrochemical operation, cementation, membrane operations, evaporation, adsorption, solidification/stabilization, and vitrification. Several case histories are described, with a focus on waste reduction techniques and remediation of lead-contaminated soils. The paper concludes with a short discussion of important research needs in the field.

Peters, R.W.; Shem, L.

1993-01-01

112

Separation of heavy metals: Removal from industrial wastewaters and contaminated soil  

Energy Technology Data Exchange (ETDEWEB)

This paper reviews the applicable separation technologies relating to removal of heavy metals from solution and from soils in order to present the state-of-the-art in the field. Each technology is briefly described and typical operating conditions and technology performance are presented. Technologies described include chemical precipitation (including hydroxide, carbonate, or sulfide reagents), coagulation/flocculation, ion exchange, solvent extraction, extraction with chelating agents, complexation, electrochemical operation, cementation, membrane operations, evaporation, adsorption, solidification/stabilization, and vitrification. Several case histories are described, with a focus on waste reduction techniques and remediation of lead-contaminated soils. The paper concludes with a short discussion of important research needs in the field.

Peters, R.W.; Shem, L.

1993-03-01

113

Neural networks-based modeling applied to a process of heavy metals removal from wastewaters.  

UK PubMed Central (United Kingdom)

This article approaches the problem of environment pollution with heavy metals from disposal of industrial wastewaters, namely removal of these metals by means of biosorbents, particularly with Romanian peat (from Poiana Stampei). The study is carried out by simulation using feed-forward and modular neural networks with one or two hidden layers, pursuing the influence of certain operating parameters (metal nature, sorbent dose, pH, temperature, initial concentration of metal ion, contact time) on the amount of metal ions retained on the unit mass of sorbent. In neural network modeling, a consistent data set was used, including five metals: lead, mercury, cadmium, nickel and cobalt, the quantification of the metal nature being done by its electronegativity. Even if based on successive trials, the method of designing neural models was systematically conducted, recording and comparing the errors obtained with different types of neural networks, having various numbers of hidden layers and neurons, number of training epochs, or using various learning methods. The errors with values under 5% make clear the efficiency of the applied method.

Suditu GD; Curteanu S; Bulgariu L

2013-01-01

114

Poly(ethylene glycol dimethacrylate-n-vinyl imidazole) beads for heavy metal removal  

International Nuclear Information System (INIS)

Poly(ethylene glycol dimethacrylate-n-vinyl imidazole) [poly(EGDMA-VIM)] hydrogel (average diameter 150-200 ?m) was prepared by copolymerizing ethylene glycol dimethacrylate (EGDMA) with n-vinyl imidazole (VIM). The copolymer hydrogel bead composition was characterized by elemental analysis and found to contain 5 EGDMA monomer units each VIM monomer unit. Poly(EGDMA-VIM) beads had a specific surface area of 59.8 m2/g. Poly(EGDMA-VIM) beads were characterized by swelling studies and scanning electron microscopy (SEM). These poly(EGDMA-VIM) beads with a swelling ratio of 78% were used for the heavy metal removal studies. Chelation capacity of the beads for the selected metal ions, i.e., Cd(II), Hg(II) and Pb(II) were investigated in aqueous media containing different amounts of these ions (10-750 mg/l) and at different pH values (3.0-7.0). Chelation rate was very fast. The maximum chelation capacities of the poly(EGDMA-VIM) beads were 69.4 mg/g for Cd(II), 114.8 mg/g for Pb(II) and 163.5 mg/g for Hg(II). The affinity order on molar basis was observed as follows: Hg(II)>Cd(II)>Pb(II). Chelation behavior of heavy metal ions could be modelled using both the Langmuir and Freundlich isotherms. pH significantly affected the chelation capacity of VIM incorporated beads. Chelation of heavy metal ions from synthetic wastewater was also studied. The chelation capacities are 45.6 mg/g for Cd(II), 74.2 mg/g for Hg(II) and 92.5 mg/g for Pb(II) at 0.5 mmol/l initial metal concentration. Regeneration of the chelating-beads was easily performed with 0.1 M HNO3. These features make poly(EGDMA-VIM) beads potential candidate adsorbent for heavy metal removal.

2004-01-30

115

Heavy Metal Removal from Aqueous Solution by Adsorption on Modified Banana Shell  

Directory of Open Access Journals (Sweden)

Full Text Available Background and Objectives: Heavy Metals in Water resources is one of the most important environmental problems of countries. Up to now various methods of removing of these metals is considered, which is including using of low prices materials. In this study the potential of banana shells was assessed for adsorption of heavy metal ions such as Pb and Cd from aqueous solution. "nMaterials and Methods: Banana shells were pretreated separately with 0.4 mol/L NaOH, 0.4 mol/L HNO and distilled water and their adsorption ability were compared. Batch adsorption experiments were carried out as a function of the initial ion concentration, pH and adsorbent dosage. Adsorption isotherms of metal ions on adsorbents were determined and correlated with common isotherm equations such as Lungmuir, Freundlich and BET models."nResults: The maximum adsorption capacities were achieved by alkali modified banana shells (36 mg/g) for Pb and by acidic modified banana shells (16 mg/g) for Cd. Experimental results showed that the best pH for adsorption was 6 and the adsorption values decreased with lowering pH. Isotherm models indicated best fit for Freundlich model for modified banana shells."nConclusion: In comparing the parameters of models, it was observed that the capacity of banana shells for adsorption of lead is higher  than for adsorption of cadmium, but the adsorption of  cadmium is stronger than the adsorption of lead.

MR Mehrasbi; Z Farahmand kia

2008-01-01

116

Removal of Heavy Metal Ions by using Calcium Carbonate Extracted from Starfish Treated by Protease and Amylase  

Directory of Open Access Journals (Sweden)

Full Text Available CaCO3 extracted from starfish by using the commercial protein lyase having ?-amylase, ?-amylase, and protease is applied to remove heavy metal ions. The extracted CaCO3 shows excellent characteristics in removing heavy metal ions such as Cu2+, Cd2+, Pb2+, and Cr6+ compared with conventional materials such as crab shells, sawdust, and activated carbon except for removing Zn2+. SEM images reveal that the extracted CaCO33 has a good morphology and porosity. We characterize the removal efficiencies of the extracted CaCO3 for the heavy metal ions according to the concentrations, pH, temperatures, and conditions of empty bed contact times.

Kyong-Soo Hong; Hak Myoung Lee; Jong Seong Bae; Myoung Gyu Ha; Jong Sung Jin; Tae Eun Hong; Jong Pil Kim; Euh Duck Jeong

2011-01-01

117

Removal of heavy metal ions from water by using calcined phosphate as a new adsorbent.  

Science.gov (United States)

Calcined phosphate (CP) has been employed in our laboratories as a heterogeneous catalyst in a variety of reactions. In this study, CP was evaluated as a new product for removal of heavy metals from aqueous solution. Removal of Pb2+, Cu2+, and Zn2+ on the CP was investigated in batch experiments. The kinetic of lead on CP adsorption efficiency and adsorption process were evaluated and analysed using the theories of Langmuir and Freundlich. The influence of pH was studied. The adsorption capacity obtained at pH 5 were 85.6, 29.8, and 20.6 mg g(-1) for Pb2+, Cu2+ and Zn2+, respectively. We hypothesize at pH 2 and 3, the dissolution of CP and precipitation of a fluoropyromorphite for lead and the formation of solid-solution type fluorapatite for copper. The results obtained show that CP is a good adsorbent for these toxic heavy metals. The abundance of natural phosphate, its low price and non-aggressive nature towards the environment are advantage for its utilisation in point of view of wastewater and wastes clean up. PMID:15302439

Aklil, A; Mouflih, M; Sebti, S

2004-08-30

118

Removal of heavy metal ions from water by using calcined phosphate as a new adsorbent.  

UK PubMed Central (United Kingdom)

Calcined phosphate (CP) has been employed in our laboratories as a heterogeneous catalyst in a variety of reactions. In this study, CP was evaluated as a new product for removal of heavy metals from aqueous solution. Removal of Pb2+, Cu2+, and Zn2+ on the CP was investigated in batch experiments. The kinetic of lead on CP adsorption efficiency and adsorption process were evaluated and analysed using the theories of Langmuir and Freundlich. The influence of pH was studied. The adsorption capacity obtained at pH 5 were 85.6, 29.8, and 20.6 mg g(-1) for Pb2+, Cu2+ and Zn2+, respectively. We hypothesize at pH 2 and 3, the dissolution of CP and precipitation of a fluoropyromorphite for lead and the formation of solid-solution type fluorapatite for copper. The results obtained show that CP is a good adsorbent for these toxic heavy metals. The abundance of natural phosphate, its low price and non-aggressive nature towards the environment are advantage for its utilisation in point of view of wastewater and wastes clean up.

Aklil A; Mouflih M; Sebti S

2004-08-01

119

Procion Green H-4G immobilized poly(hydroxyethylmethacrylate/chitosan) composite membranes for heavy metal removal  

International Nuclear Information System (INIS)

[en] The effective removal of toxic heavy metals from environmental samples still remains a major topic of present research. Metal-chelating membranes are very promising materials as adsorbents when compared with conventional beads because they are not compressible, and they eliminate internal diffusion limitations. The purpose of this study was to evaluate the performance of a novel adsorbent, Procion Green H-4G immobilized poly(hydroxyethylmethacrylate (HEMA)/chitosan) composite membranes, for the removal of three toxic heavy metal ions, namely, Cd(II), Pb(II) and Hg(II) from aquatic systems. The Procion Green H-4G immobilized poly(hydroxyethylmethacrylate/chitosan) composite membranes were characterized by elemental analysis, scanning electron microscopy and Fourier transform infrared (FTIR) spectroscopy. The immobilized amount of the Procion Green H-4G was calculated as 0.018±0.003 ?mol/cm2 from the nitrogen and sulphur stoichiometry. The adsorption capacity of Procion Green H-4G immobilized poly(hydroxyethylmethacrylate/chitosan) composite membranes for selected heavy metal ions from aqueous media containing different amounts of these ions (30-400 mg/l) and at different pH values (2.0-6.0) was investigated. The amount of Cd(II), Pb(II) and Hg(II) adsorbed onto the membranes measured at equilibrium, increased with time during the first 45 min and then remained unchanged toward the equilibrium adsorption. The maximum amounts of heavy metal ions adsorbed were 43.60±1.74, 68.81±2.75 and 48.22±1.92 mg/g for Cd(II), Pb(II) and Hg(II), respectively. The heavy metal ion adsorption on the pHEMA/chitosan membranes (carrying no dye) were relatively low, 6.31±0.13 mg/g for Cd(II), 18.73±0.37 mg/g for Pb(II) and 18.82±0.38 mg/g for Hg(II). Competitive adsorption of the metal ions was also studied. When the metal ions competed with each other, the adsorbed amounts were 12.74±0.38 mg Cd(II)/g, 28.80±0.86 mg Pb(II)/g and 18.41±0.54 mg Hg(II)/g. Procion Green H-4G immobilized poly(hydroxyethylmethacrylate/chitosan) membranes can be regenerated by washing with a solution of nitric acid (0.01 M). The percent desorption achieved was as high as 95%. These novel membranes are suitable for repeated use for more than five adsorption/desorption cycles without any considerable loss in adsorption capacity. Adsorption equilibria were well described by Langmuir equation. It can be concluded that Procion Green H-4G immobilized poly(hydroxyethylmethacrylate/chitosan) membranes may effectively be used for the removal of Cd(II), Pb(II) and Hg(II) ions from aqueous solutions

2003-02-28

120

Method of removal of heavy metal from molten salt in IFR fuel pyroprocessing  

Science.gov (United States)

An electrochemical method of separating heavy metal values from a radioactive molten salt including Li halide at temperatures of about 500.degree. C. The method comprises positioning a solid Li--Cd alloy anode in the molten salt containing the heavy metal values, positioning a Cd-containing cathode or a solid cathode positioned above a catch crucible in the molten salt to recover the heavy metal values, establishing a voltage drop between the anode and the cathode to deposit material at the cathode to reduce the concentration of heavy metals in the salt, and controlling the deposition rate at the cathode by controlling the current between the anode and cathode.

Gay, Eddie C. (Park Forest, IL)

1995-01-01

 
 
 
 
121

USE OF CLAY TO REMOVE HEAVY METALS FROM JEBEL CHAKIR LANDFILL LEACHATE  

Directory of Open Access Journals (Sweden)

Full Text Available Adsorptive removal of copper and nickel from Jebel Chakir landfill leachate onto smectite-rich clayey rock were carried out by both batch and column methods. The raw AYD clay was sampled in El Hamma area (Tunisia). The adsorbent employed was characterized by X-ray diffraction, specific surface area, cation exchange capacity and point of zero charge. Results showed that raw AYD clay possesses a high surface area owing to its mineralogical composition. An increase in the clay quantity from 0.5 to 5.5g generates a reduction in the quantity of metals adsorbed in the solid phase. The adsorption of heavy metals increases with a decrease in the pH leachate from 8.11 to 5.0. The column experiments showed that the addition of sand to the J. Aïdoudi clay can be useful for leachate depollution, but for a few volume due to the fine fraction of this clay (< 2µm = 89.6%). the comparison study of the heavy metals adsorption on raw AYD clay by the two modes of adsorption (batch and column) showed that column test are better than that obtained by batch test.

ISLEM CHAARI; Mounir Medhioub; FAKHER JAMOUSSI

2011-01-01

122

BIOSORPTIVE REMOVAL OF HEAVY METALS (Cd+2, Pb+2 AND Cu+2) FROM AQUEOUS SOLUTIONS BY CASSIA ANGUSTIFOLIA BARK  

Directory of Open Access Journals (Sweden)

Full Text Available The hazardous ill effects of heavy metals on the environment and public health is a matter of serious concern. Biosorption is emerging as a sustainable effective technology. The aim of this present study was to investigate the removal of heavy metals (Cd+2, Pb+2 and Cu+2) using Cassia angustifolia bark. The objective was to evaluate the biosorbent for its metal uptake and study its batch equilibrium. The batch mode was carried out at varying initial pH (5 to 9), emperature (300C to 450C), metal ion concentration (20mg to 140mg/L) and contact time (5 min to 240 min) and desorption studies from pH 1 to 11. The equilibrium data obtained fit well in Langmuir and Freundlich isotherms. The results of the investigations show the efficacy of Cassia angustifolia bark as a low cost promising biosorbent for removal of heavy metals from industrial wastewaters.

MADHAVI G MULGUND,; P.T.KININGE; M.M.PILLAI,; M.R.SANANDAM

2011-01-01

123

Remediation of heavy metal polluted sediment by suspension and solid-bed leaching: estimate of metal removal efficiency.  

UK PubMed Central (United Kingdom)

Remediation of heavy metal polluted sediment by extracting the metals with sulfuric acid can be performed as follows: abiotic suspension leaching, microbial suspension leaching, abiotic solid-bed leaching, and microbial solid-bed leaching. Abiotic leaching means that the acid is directly added, while microbial leaching means that the acid is generated from sulfur by microbes (bioleaching). These four principles were compared to each other with special emphasis on the effectiveness of metal solubilization and metal removal by subsequent washing. Abiotic suspension leaching was fastest, but suspending the solids exhibits some disadvantages (low solid content, costly reactors, permanent input of energy, high water consumption, special equipment required for solid separation, large amounts of waste water, sediment properties hinder reuse), which prevent suspension leaching in practice. Abiotic solid-bed leaching implies the supply of acid by percolating water which proceeds slowly due to a limited bed permeability. Microbial solid-bed leaching means the generation of acid within the bed and has been proven to be the only principle applicable to practice. Metal removal from leached sediment requires washing with water. Washing of solid beds was much more effective than washing of suspended sediment. The kinetics of metal removal from solid beds 0.3, 0.6 or 1.2m in height were similar; when using a percolation flow of 20lm(-2)h(-1), the removal of 98% of the mobile metals lasted 57-61h and required 8.5, 4.2 or 2.3lkg(-1) water. This means, the higher the solid bed, the lower the sediment-mass-specific demand for time and water.

Löser C; Zehnsdorf A; Hoffmann P; Seidel H

2007-01-01

124

Organic substrates as electron donors in permeable reactive barriers for removal of heavy metals from acid mine drainage.  

UK PubMed Central (United Kingdom)

This research was conducted to select suitable natural organic substrates as potential carbon sources for use as electron donors for biological sulphate reduction in a permeable reactive barrier (PRB). A number of organic substrates were assessed through batch and continuous column experiments under anaerobic conditions with acid mine drainage (AMD) obtained from an abandoned lignite coal mine. To keep the heavy metal concentration at a constant level, the AMD was supplemented with heavy metals whenever necessary. Under anaerobic conditions, sulphate-reducing bacteria (SRB) converted sulphate into sulphide using the organic substrates as electron donors. The sulphide that was generated precipitated heavy metals as metal sulphides. Organic substrates, which yielded the highest sulphate reduction in batch tests, were selected for continuous column experiments which lasted over 200 days. A mixture of pig-farm wastewater treatment sludge, rice husk and coconut husk chips yielded the best heavy metal (Fe, Cu, Zn and Mn) removal efficiencies of over 90%.

Kijjanapanich P; Pakdeerattanamint K; Lens PN; Annachhatre AP

2012-12-01

125

Growth and heavy metal removal by Klebsiella aerogenes at different pH and temperature  

Energy Technology Data Exchange (ETDEWEB)

A strain of Klebsiella aerogenes isolated from Rustamiyah Station for treatment of wastewater was examined for its ability to grow in a media supplemented with maximum tolerance concentrations of Pb/sup + +/, Zn/sup + +/, Ni/sup + +/, and Cd/sup + +/, separately, at different temperatures and initial pH. The results indicated that at 28/sup 0/C during the first 24 hr, Pb/sup + +/ and Ni/sup + +/ had no effect on the growth of the bacteria, while the presence of Zn/sup + +/ and Cd/sup + +/ decreased the cell count. The growth reached a maximum level after the second day and started to decrease gradually. The bacterial count at 37/sup 0/C was less than that at 28/sup 0/C. No bacterial multiplication occurred at 44/sup 0/C. There was little difference between heavy metal removal at 28 and 37/sup 0/C. At 44/sup 0/C, little removal took place. In general, slightly acidic or neutral medium was better for both bacterial growth and metal removal.

Al-Shahwani, M.F.; Jazrawi, S.F.; Al-Rawi, E.H.; Ayar, N.S.

1984-01-01

126

Removal turbidity and separation of heavy metals using electrocoagulation-electroflotation technique  

International Nuclear Information System (INIS)

The electrocoagulation (EC) process was developed to overcome the drawbacks of conventional wastewater treatment technologies. This process is very effective in removing organic pollutants including dyestuff wastewater and allows for the reduction of sludge generation. The purposes of this study were to investigate the effects of the operating parameters, such as pH, initial concentration (C0), duration of treatment (t), current density (j), interelectrode distance (d) and conductivity (?) on a synthetic wastewater in the batch electrocoagulation-electroflotation (EF) process. The optimal operating conditions were determined and applied to a textile wastewater and separation of some heavy metals. Initially a batch-type EC-EF reactor was operated at various current densities (11.55, 18.6, 35.94, 56.64, 74.07 and 91.5 mA/cm2) and various interelectrode distance (1, 2 and 3 cm). For solutions with 300 mg/L of silica gel, high turbidity removal (89.54%) was obtained without any coagulants when the current density was 11.55 mA/cm2, initial pH was 7.6, conductivity was 2.1 mS/cm, duration of treatment was 10 min and interelectrode distance was 1 cm. The application of the optimal operating parameters on a textile wastewater showed a high removal efficiency for various items: suspended solid (SS) 86.5%, turbidity 81.56%, biological oxygen demand (BOD5) 83%, chemical oxygen demand (COD) 68%, and color over 92.5%. During the EC process under these conditions, we have studied the separation of some heavy metal ions such as iron (Fe), nickel (Ni), copper (Cu), zinc (Zn), lead (Pb) and cadmium (Cd) with different initial concentrations in the range of 50-600 mg/L and initial pH between 7.5 and 7.8. This allowed us to show that the kinetics of electrocoagulation-electroflotation is very quick (

2009-05-15

127

Hydrogen sulfide removal from coal gas by the metal-ferrite sorbents made from the heavy metal wastewater sludge.  

UK PubMed Central (United Kingdom)

The metal-ferrite (chromium-ferrite and zinc-ferrite) sorbents made from the heavy metal wastewater sludge have been developed for the hydrogen sulfide removal from coal gas. The high temperature absorption of hydrogen sulfide from coal gas with the metal-ferrite sorbent in a fixed bed reactor was conducted in this study. The metal-ferrite powders were the products of the ferrite process for the heavy metal wastewater treatment. The porosity analysis results show that the number of micropores of the sorbents after sulfidation and regeneration process decreases and the average pore size increases due to the acute endothermic and exothermic reactions during the sulfidation-regeneration process. The FeS, ZnS, and MnS peaks are observed on the sulfided sorbents, and the chromium extraction of the CFR6 can fulfill the emission standard of Taiwan EPA. The suitable sulfidation temperature range for chromium-ferrite sorbent is at 500-600 degrees C. In addition, effects of various concentrations of H2 and CO were also conducted in the present work at different temperatures. By increasing the H2 concentration, the sulfur sorption capacity of the sorbent decreases and an adverse result is observed in the case of increasing CO concentration. This can be explained via water-shift reaction.

Tseng TK; Chang HC; Chu H; Chen HT

2008-12-01

128

Hydrogen sulfide removal from coal gas by the metal-ferrite sorbents made from the heavy metal wastewater sludge.  

Science.gov (United States)

The metal-ferrite (chromium-ferrite and zinc-ferrite) sorbents made from the heavy metal wastewater sludge have been developed for the hydrogen sulfide removal from coal gas. The high temperature absorption of hydrogen sulfide from coal gas with the metal-ferrite sorbent in a fixed bed reactor was conducted in this study. The metal-ferrite powders were the products of the ferrite process for the heavy metal wastewater treatment. The porosity analysis results show that the number of micropores of the sorbents after sulfidation and regeneration process decreases and the average pore size increases due to the acute endothermic and exothermic reactions during the sulfidation-regeneration process. The FeS, ZnS, and MnS peaks are observed on the sulfided sorbents, and the chromium extraction of the CFR6 can fulfill the emission standard of Taiwan EPA. The suitable sulfidation temperature range for chromium-ferrite sorbent is at 500-600 degrees C. In addition, effects of various concentrations of H2 and CO were also conducted in the present work at different temperatures. By increasing the H2 concentration, the sulfur sorption capacity of the sorbent decreases and an adverse result is observed in the case of increasing CO concentration. This can be explained via water-shift reaction. PMID:18440697

Tseng, Ting Ke; Chang, Han Ching; Chu, Hsin; Chen, Hung Ta

2008-03-20

129

Development of the removal technology for toxic heavy metal ions by surface-modified activated carbon  

International Nuclear Information System (INIS)

Adsorption capacities of both radionuclides(uranium, cobalt) and toxic heavy metals (lead, cadmium and chromium) using double surface-modified activated carbon in wide pH ranges are extensively evaluated. Surface-modified activated carbons are classified as AC(as-received carbon), OAC(single surface-modified carbon with nitric acid solution) and OAC-Na(double surface-modified carbon with various alkali solutions). It is established that optimal condition for the second surface modification of OAC is to use the mixed solution of both NaOH and NaCl with total concentration of 0.1 N based on adsorption efficiencies of uranium and cobalt. Variations of adsorption efficiencies in pH ranges of 2?10 and the adsorption capacities in batch adsorber and fixed bed for removal of both radionuclides and toxic heavy metals using OAC-Na were shown to be superior to that of the AC and OAC even in a low pH range. Capacity factors of OAC-Na for the removal of various metal ions are also excellent to that of AC or OAC. Quantitative analysis of capacity factors for each ions showed that adsorption capacity of OAC-Na increased by 30 times for uranium, 60 times for cobalt, 9 times for lead, 30 times for cadmium, 3 times for chromium compared to that of AC at pH 5, respectively. Adsorption capacity of OAC-Na is comparable to that of XAD-16-TAR used as commercial ion exchange resin.

2001-01-01

130

Removal and treatment of radioactive, organochlorine, and heavy metal contaminants from solid surfaces  

International Nuclear Information System (INIS)

The U.S. Department of Energy (DOE) is defining decontamination and decommissioning (D ampersand D) obligations at its sites. Current D ampersand D activities are generally labor intensive, use chemical reagents that are difficult to treat, and may expose workers to radioactive and hazardous chemicals. Therefore, new technologies are desired that minimize waste, allow much of the decommissioned materials to be reused rather than disposed of as waste, and produce wastes that will meet disposal criteria. The O'Brien ampersand Gere companies tested a scouring decontamination system on concrete and steel surfaces contaminated with radioactive and hazardous wastes under the sponsorship of Martin Marietta Energy Systems, Inc. (MMES) at DOE's K-25 former gaseous diffusion plant in Oak Ridge, Tennessee. The scouring system removes fixed radioactive and hazardous contamination yet leaves the surface intact. Blasting residuals are treated using physical/chemical processes. Bench- and pilot-scale testing of the system was conducted on surfaces contaminated with uranium, technetium, heavy metals, and PCBs. Areas of concrete and metal surfaces were blasted. Residuals were dissolved in tap water and treated for radioactive, hazardous, and organochlorine constituents. The treatment system comprised pH adjustment, aeration, solids settling, filtration, carbon adsorption, and ion exchange. This system produced treated water and residual solid waste. Testing demonstrated that the system is capable of removing greater than 95% of radioactive and PCB surface contamination to below DOE's unrestricted use release limits; aqueous radionuclides, heavy metals, and PCBs were below DOE and USEPA treatment objectives after treatment. Waste residuals volume was decreased by 71 %. Preliminary analyses suggest that this system provides significant waste volume reduction and is more economical than alternative surface decontamination techniques that are commercially available or under development.

1996-01-01

131

Removal and treatment of radioactive, organochlorine and heavy metal contaminants from solid surfaces  

International Nuclear Information System (INIS)

The U.S. Department of Energy (DOE) is defining decontamination and decommissioning (D ampersand D) obligations at its sites. Current D ampersand D activities are Generally labor intensive, use chemical reagents that are difficult to treat, and may expose workers to radioactive and hazardous chemicals. Therefore, new technologies are desired that minimize waste, allow much of the decommissioned materials to be reused rather than disposed of as waste, and produce wastes that will meet disposal criteria The O'Brien ampersand Gere Companies tested a scouring decontamination system on concrete and steel surfaces contaminated with radioactive and hazardous wastes under the sponsorship of Martin Marietta Energy Systems, Inc. (MMES) at DOE's K-25 former gaseous diffusion plant in Oak Ridge, Tennessee. The scouring system that O'Brien ampersand Gere Companies developed removes fixed radioactive and hazardous surface contamination, while leaving the surface intact. Blasting residuals are dissolved and treated using physical/chemical processes. Bench- and pilot-scale testing of the soda blasting system was conducted between December 1993 and September 1994 on surfaces contaminated with uranium, technetium, heavy metals, and PCBs. Areas of concrete and metal surfaces were blasted. Blasting residuals were dissolved in tap water and treated for radioactive, hazardous, and organochlorine constituents. The treatment system comprised pH adjustment, aeration, solids settling, filtration, carbon adsorption, and ion exchange. This system produced treated water and residual solid waste. Testing demonstrated that the system is capable of removing greater than 95% of radioactive and PCB surface contamination to below DOE's unrestricted use release limits; aqueous radionuclides, heavy metals, and PCBs were below DOE and USEPA treatment objectives after blasting residuals treatment. Waste residuals volume was decreased by 71%.

1996-01-01

132

Heavy metal removal and crude bio-oil upgrade from Sedum alfredii Hance harvest using hydrothermal upgrading.  

Science.gov (United States)

In this study, heavy metals were removed and crude bio-oil was yielded from a heavy metal hyperaccumulator harvest, Sedum alfredii Hance, through hydrothermal upgrading process. This paper reports on the optimization of process parameters for the removal of heavy metals (zinc, lead, and copper) and for the upgrading of crude bio-oil from this biomass in an autoclave. Parameters such as granularity, temperature, pressure, and duration were examined for their effect on the removal efficiency of heavy metals and upgrading efficacy of crude bio-oil. Maximum heavy metal removal efficiency of >99% and crude bio-oil upgrading efficiency of >60% were attained with an 18 mesh (1 mm) granularity, and 22.1 MPa at 370 degrees C in the presence of 10 mg/L additives (K(2)CO(3)) for 60 s. Under these optimized conditions, an oil phase (mostly composed of phenolic hydrocarbons and derivatives), a water phase raffinate (containing Zn(2+) (0.39 g/L), Pb(2+) (0.10 g/L), Cu(2+) (0.15 g/L)), and a solid phase (the hydrothermal upgrading residue, which completely satisfies the limit set by China legislation related to biosolids disposal) were obtained. PMID:20409636

Yang, Jian-guang; Tang, Chao-bo; He, Jing; Yang, Sheng-Hai; Tang, Mo-tang

2010-04-02

133

Heavy metal removal and crude bio-oil upgrade from Sedum alfredii Hance harvest using hydrothermal upgrading.  

UK PubMed Central (United Kingdom)

In this study, heavy metals were removed and crude bio-oil was yielded from a heavy metal hyperaccumulator harvest, Sedum alfredii Hance, through hydrothermal upgrading process. This paper reports on the optimization of process parameters for the removal of heavy metals (zinc, lead, and copper) and for the upgrading of crude bio-oil from this biomass in an autoclave. Parameters such as granularity, temperature, pressure, and duration were examined for their effect on the removal efficiency of heavy metals and upgrading efficacy of crude bio-oil. Maximum heavy metal removal efficiency of >99% and crude bio-oil upgrading efficiency of >60% were attained with an 18 mesh (1 mm) granularity, and 22.1 MPa at 370 degrees C in the presence of 10 mg/L additives (K(2)CO(3)) for 60 s. Under these optimized conditions, an oil phase (mostly composed of phenolic hydrocarbons and derivatives), a water phase raffinate (containing Zn(2+) (0.39 g/L), Pb(2+) (0.10 g/L), Cu(2+) (0.15 g/L)), and a solid phase (the hydrothermal upgrading residue, which completely satisfies the limit set by China legislation related to biosolids disposal) were obtained.

Yang JG; Tang CB; He J; Yang SH; Tang MT

2010-07-01

134

Removal of heavy metals from aqueous solution by lipopeptides and lipopeptides modified Na-montmorillonite.  

Science.gov (United States)

The removal of Cu(2+), Zn(2+), Cd(2+), Pb(2+) and Hg(2+) from aqueous solution by lipopeptides produced from solid-state fermentation (LPSSF) and LPSSF modified Na-montmorillonite clays (LPSSF/Na-MMT) was investigated. The results showed that the LPSSF had certain adsorption capability for the metal ions and the modification of Na-MMT with LPSSF at a weight ratio of 1:50 (LPSSF:Na-MMT) had the best adsorption capacity and adsorption rate. The adsorption of heavy metal ion on these adsorbents was monolayer sorption. And the rate limiting step of the adsorption process was thought as chemical sorption. The N-C-O and CC/CN groups of the LPSSF are the functional groups that were responsible for complexing the metal ions. The desorption rate of metal ions reached over 80% at 500mg/L of LPSSF. The LPSSF/Na-MMT (1:50) was reusable and performed well in the complex system, indicating its potential application in wastewater treatment. PMID:23999267

Zhu, Zhen; Gao, Chao; Wu, Yanliang; Sun, Lifei; Huang, Xiaolei; Ran, Wei; Shen, Qirong

2013-08-13

135

Removal of heavy metals from aqueous solution by lipopeptides and lipopeptides modified Na-montmorillonite.  

UK PubMed Central (United Kingdom)

The removal of Cu(2+), Zn(2+), Cd(2+), Pb(2+) and Hg(2+) from aqueous solution by lipopeptides produced from solid-state fermentation (LPSSF) and LPSSF modified Na-montmorillonite clays (LPSSF/Na-MMT) was investigated. The results showed that the LPSSF had certain adsorption capability for the metal ions and the modification of Na-MMT with LPSSF at a weight ratio of 1:50 (LPSSF:Na-MMT) had the best adsorption capacity and adsorption rate. The adsorption of heavy metal ion on these adsorbents was monolayer sorption. And the rate limiting step of the adsorption process was thought as chemical sorption. The N-C-O and CC/CN groups of the LPSSF are the functional groups that were responsible for complexing the metal ions. The desorption rate of metal ions reached over 80% at 500mg/L of LPSSF. The LPSSF/Na-MMT (1:50) was reusable and performed well in the complex system, indicating its potential application in wastewater treatment.

Zhu Z; Gao C; Wu Y; Sun L; Huang X; Ran W; Shen Q

2013-11-01

136

Molecular Characterization and Phylogenetic Analyses of Heavy Metal Removal Bacteria from the Persian Gulf  

Directory of Open Access Journals (Sweden)

Full Text Available A total of 35 heavy metals resistance and removal bacterial strains were isolated from samples of marine environment and enclosed industrial areas. All isolates were characterized by molecular method. The diversity of isolated bacteria was examined by the phylogenetic analysis of 16S rRNA gene sequences. The phylogenetic analysis of the sequences revealed seven main taxonomic lineages. The phylogenetic tree illustrated discrimination between isolated bacteria from wastewater, industrials area and marine environment. Results showed new genetic differences and relationship between marine and industrial strains. Some Pseudomonas strains isolated from marine environment were well differentiated from those of industrial wastewater. Members of the genera Delftia and Bacterium formed a monophyletic group within the subdivision of the class. There was a clear differentiation between two groups of Pseudomonas and other groups of bacteria in the phylogenetic tree.

H. Zolgharnein; K. Karami; M. Mazaheri Assadi; A. Dadolahi Sohrab

2010-01-01

137

Heavy metal removal in anaerobic semi-continuous stirred tank reactors by a consortium of sulfate-reducing bacteria.  

Science.gov (United States)

Removal of heavy metals by an enriched consortium of sulfate-reducing bacteria (SRB) was evaluated through the abundance of SRB, sulfate reduction, sulfide production and heavy metal precipitation. Five parallel anaerobic semi-continuous stirred tank reactors (CSTR, V = 2 L) (referred as R1-R5) were fed with synthetic wastewater containing mixtures of Cu(2+), Zn(2+), Ni(2+), and Cr(6+) in the concentrations of 30, 60, 90, 120, and 150 mg L(-1) of each metal and operated with a hydraulic retention time of 20 days for 12 weeks. The loading rates of each metal in R1-R5 were 1.5, 3, 4.5, 6, and 7.5 mg L(-1) d(-1), respectively. The results showed that there was no inhibition of SRB growth and that heavy metal removal efficiencies of 94-100% for Cu(2+), Zn(2+), Ni(2+), and Cr(6+) were achieved in R1-R3 throughout the experiment and in R4 during the first 8 weeks. The toxic effect of heavy metals on the SRB consortium was revealed in R5, in which no SRB could survive and almost no heavy metal precipitation was detected after four weeks of operation. PMID:21632086

Kieu, Hoa T Q; Müller, Elizabeth; Horn, Harald

2011-05-11

138

Heavy metal removal in anaerobic semi-continuous stirred tank reactors by a consortium of sulfate-reducing bacteria.  

UK PubMed Central (United Kingdom)

Removal of heavy metals by an enriched consortium of sulfate-reducing bacteria (SRB) was evaluated through the abundance of SRB, sulfate reduction, sulfide production and heavy metal precipitation. Five parallel anaerobic semi-continuous stirred tank reactors (CSTR, V = 2 L) (referred as R1-R5) were fed with synthetic wastewater containing mixtures of Cu(2+), Zn(2+), Ni(2+), and Cr(6+) in the concentrations of 30, 60, 90, 120, and 150 mg L(-1) of each metal and operated with a hydraulic retention time of 20 days for 12 weeks. The loading rates of each metal in R1-R5 were 1.5, 3, 4.5, 6, and 7.5 mg L(-1) d(-1), respectively. The results showed that there was no inhibition of SRB growth and that heavy metal removal efficiencies of 94-100% for Cu(2+), Zn(2+), Ni(2+), and Cr(6+) were achieved in R1-R3 throughout the experiment and in R4 during the first 8 weeks. The toxic effect of heavy metals on the SRB consortium was revealed in R5, in which no SRB could survive and almost no heavy metal precipitation was detected after four weeks of operation.

Kieu HT; Müller E; Horn H

2011-07-01

139

Application of Multiwalled Carbon Nanotube-Cyclodextrin Polymers in the Removal of Heavy Metals from Water  

Directory of Open Access Journals (Sweden)

Full Text Available The aim of this study was to synthesize oxidized multiwalled carbon nanotube-cyclodextrin polymer and explore the possibility of using this polymer for the remediation of heavy metal contamination in the aquatic environment. Herein we report the results obtained from testing the polymer for the removal of lead and cobalt from synthetic water solutions. The performance of the polymer was matched against pristine and oxidized multiwalled carbon nanotubes. The polymer was found to perform better at lower concentrations (10 mg L-1) with adsorption capacities of 4.08 and 3.89 mg g-1 for lead and cobalt, respectively. These correspond to 68.0 and 64.8% removal of lead and cobalt, respectively. The maximum adsorption capacity of the polymer from the Langmuir isotherms was calculated to be 28.86 and 21.44 mg g-1 for lead and cobalt, respectively, at an initial concentration range of 10-50 mg L-1. Competitive adsorption studies revealed that lead is adsorbed better than cobalt. Furthermore, the adsorption capacity of the polymer is lower in the competitive adsorption than in the single metal ion adsorption, suggesting competition between the lead and cobalt ions.

G. Mamba; X.Y. Mbianda; P.P. Govender; B.B. Mamba; R.W. Krause

2010-01-01

140

Biotreatment and bioassessment of heavy metal removal by sulphate reducing bacteria in fixed bed reactors.  

UK PubMed Central (United Kingdom)

In this work a batch-optimised mixture (w/w %: 6% leaves, 9% compost, 3% Fe(0), 30% silica sand, 30% perlite, 22% limestone) was investigated in a continuous fixed bed column reactor for the treatment of synthetic acid-mine drainage (AMD). A column reactor was inoculated with sulphate-reducing bacteria and fed with a solution containing sulphate and heavy metals (As(V), Cd, Cr(VI), Cu and Zn). At steady state, sulphate abatement was 50+/-10%, while metals were totally removed. A degradation rate constant (k) of 0.015+/-0.001h(-1) for sulphate removal was determined from column data by assuming a first order degradation rate. Reduction of AMD toxicity was assessed by using the nematode Caenorhabditis elegans as a test organism. A lethality assay was performed with the toxicants before and after the treatment, showing that only 5% of the animals were still alive after 48h in presence of the contaminants, while the percentage increased to 73% when the nematodes were exposed to the solution eluted from the column.

Cruz Viggi C; Pagnanelli F; Cibati A; Uccelletti D; Palleschi C; Toro L

2010-01-01

 
 
 
 
141

Biotreatment and bioassessment of heavy metal removal by sulphate reducing bacteria in fixed bed reactors.  

Science.gov (United States)

In this work a batch-optimised mixture (w/w %: 6% leaves, 9% compost, 3% Fe(0), 30% silica sand, 30% perlite, 22% limestone) was investigated in a continuous fixed bed column reactor for the treatment of synthetic acid-mine drainage (AMD). A column reactor was inoculated with sulphate-reducing bacteria and fed with a solution containing sulphate and heavy metals (As(V), Cd, Cr(VI), Cu and Zn). At steady state, sulphate abatement was 50+/-10%, while metals were totally removed. A degradation rate constant (k) of 0.015+/-0.001h(-1) for sulphate removal was determined from column data by assuming a first order degradation rate. Reduction of AMD toxicity was assessed by using the nematode Caenorhabditis elegans as a test organism. A lethality assay was performed with the toxicants before and after the treatment, showing that only 5% of the animals were still alive after 48h in presence of the contaminants, while the percentage increased to 73% when the nematodes were exposed to the solution eluted from the column. PMID:19804893

Cruz Viggi, C; Pagnanelli, F; Cibati, A; Uccelletti, D; Palleschi, C; Toro, L

2009-09-10

142

Removal turbidity and separation of heavy metals using electrocoagulation-electroflotation technique  

Energy Technology Data Exchange (ETDEWEB)

The electrocoagulation (EC) process was developed to overcome the drawbacks of conventional wastewater treatment technologies. This process is very effective in removing organic pollutants including dyestuff wastewater and allows for the reduction of sludge generation. The purposes of this study were to investigate the effects of the operating parameters, such as pH, initial concentration (C{sub 0}), duration of treatment (t), current density (j), interelectrode distance (d) and conductivity ({kappa}) on a synthetic wastewater in the batch electrocoagulation-electroflotation (EF) process. The optimal operating conditions were determined and applied to a textile wastewater and separation of some heavy metals. Initially a batch-type EC-EF reactor was operated at various current densities (11.55, 18.6, 35.94, 56.64, 74.07 and 91.5 mA/cm{sup 2}) and various interelectrode distance (1, 2 and 3 cm). For solutions with 300 mg/L of silica gel, high turbidity removal (89.54%) was obtained without any coagulants when the current density was 11.55 mA/cm{sup 2}, initial pH was 7.6, conductivity was 2.1 mS/cm, duration of treatment was 10 min and interelectrode distance was 1 cm. The application of the optimal operating parameters on a textile wastewater showed a high removal efficiency for various items: suspended solid (SS) 86.5%, turbidity 81.56%, biological oxygen demand (BOD{sub 5}) 83%, chemical oxygen demand (COD) 68%, and color over 92.5%. During the EC process under these conditions, we have studied the separation of some heavy metal ions such as iron (Fe), nickel (Ni), copper (Cu), zinc (Zn), lead (Pb) and cadmium (Cd) with different initial concentrations in the range of 50-600 mg/L and initial pH between 7.5 and 7.8. This allowed us to show that the kinetics of electrocoagulation-electroflotation is very quick (<15 min), and the removal rate reaches 95%.

Merzouk, B. [Departement d' Hydraulique, Universite Mohamed Boudiaf de M' sila (Algeria)], E-mail: mbelkov@yahoo.fr; Gourich, B. [Laboratoire de Genie des Procedes, Ecole Superieure de Technologie de Casablanca, B.P. 8012, Oasis (Morocco); Sekki, A. [Departement de Genie des Procedes, Universite Ferhat Abbas de Setif (Algeria); Madani, K.; Chibane, M. [Faculte des Sciences de la Nature et de la Vie, Universite A - Mira de Bejaia (Algeria)

2009-05-15

143

Heavy metal removal and recovery using microorganisms. Volume 1, State-of-the-art and potential applications at the SRS  

Energy Technology Data Exchange (ETDEWEB)

Microorganisms -- bacteria, fungi, and microalgae -- can accumulate relatively large amounts of toxic heavy metals and radionuclides from the environment. These organisms often exhibit specificity for particular metals. The metal content of microbial biomass can be a substantial fraction of total dry weight with concentration factors (metal in dry biomass to metal in solution) exceeding one million in some cases. Both living and inert (dead) microbial biomass can be used to reduce heavy metal concentrations in contaminated waters to very low levels -- parts per billion and even lower. In many respects (e.g. specificity, residual metal concentrations, accumulation factors, and economics) microbial bioremoval processes can be superior to conventional processes, such as ion exchange and caustic (lime or hydroxide) precipitation for heavy metals removal from waste and contaminated waters. Thus, bioremoval could be developed to contribute to the clean-up of wastes at the Savannah River Site (SRS) and other DOE facilities. However, the potential advantages of bioremoval processes must still be developed into practical operating systems. A detailed review of the literature suggests that appropriate bioremoval processes could be developed for the SRS. There is great variability from one biomass source to another in bioremoval capabilities. Bioremoval is affected by pH, other ions, temperature, and many other factors. The biological (living vs. dead) and physical (immobilized vs. dispersed) characteristics of the biomass also greatly affect metal binding. Even subtle differences in the microbial biomass, such as the conditions under which it was cultivated, can have major effects on heavy metal binding.

Wilde, E.W. [Westinghouse Savannah River Co., Aiken, SC (United States); Benemann, J.R. [Benemann (J.R.), Pinole, CA (United States)

1991-02-01

144

Influence of the civil construction debris layer in heavy metals removal of the leachate submitted to recirculation in landfill  

Directory of Open Access Journals (Sweden)

Full Text Available Little is known about the ability of stabilized organic matter (old MSW) and construction waste (RCC) to retain heavy metals from leachate generated in landfills. The objective of this study was to assess the potential of MSW to remove old heavy metals in MSW leachate produced by freshly collected, and the effect of RCC in the concentration of heavy metals in effluents from MSW old. In three columns (CR), put a layer of RCC and then MSW old and, on the other three (SR), only MSW old. Analyzed in the leachate and effluent pH, EC, BOD and metals Zn, Cd, Cu and Pb. There were similar and efficient removal of BOD and heavy metals in both treatments. The presence of the layer of RCC was considered important to the overall improvement in effluent quality, but did not influence the concentration of metals in the effluent. The order of retention of metals in the columns was: Cu ~ Pb> Cd> Zn. With the exception of Cd and Zn, all other variables assessed in the effluent were below the maximum standards set in DN 01.08 COPAM / CERH for release effluent into water bodies.

Katia Gonçalves Gutierrez; Antônio Teixeira Matos; Maike Rossmann

2010-01-01

145

Enhanced chitosan beads-supported Fe(0)-nanoparticles for removal of heavy metals from electroplating wastewater in permeable reactive barriers.  

Science.gov (United States)

The removal of heavy metals from electroplating wastewater is a matter of paramount importance due to their high toxicity causing major environmental pollution problems. Nanoscale zero-valent iron (NZVI) became more effective to remove heavy metals from electroplating wastewater when enhanced chitosan (CS) beads were introduced as a support material in permeable reactive barriers (PRBs). The removal rate of Cr (VI) decreased with an increase of pH and initial Cr (VI) concentration. However, the removal rates of Cu (II), Cd (II) and Pb (II) increased with an increase of pH while decreased with an increase of their initial concentrations. The initial concentrations of heavy metals showed an effect on their removal sequence. Scanning electron microscope images showed that CS-NZVI beads enhanced by ethylene glycol diglycidyl ether (EGDE) had a loose and porous surface with a nucleus-shell structure. The pore size of the nucleus ranged from 19.2 to 138.6 ?m with an average aperture size of around 58.6 ?m. The shell showed a tube structure and electroplating wastewaters may reach NZVI through these tubes. X-ray photoelectron spectroscope (XPS) demonstrated that the reduction of Cr (VI) to Cr (III) was complete in less than 2 h. Cu (II) and Pb (II) were removed via predominant reduction and auxiliary adsorption. However, main adsorption and auxiliary reduction worked for the removal of Cd (II). The removal rate of total Cr, Cu (II), Cd (II) and Pb (II) from actual electroplating wastewater was 89.4%, 98.9%, 94.9% and 99.4%, respectively. The findings revealed that EGDE-CS-NZVI-beads PRBs had the capacity to remediate actual electroplating wastewater and may become an effective and promising technology for in situ remediation of heavy metals. PMID:24075723

Liu, Tingyi; Yang, Xi; Wang, Zhong-Liang; Yan, Xiaoxing

2013-09-14

146

Enhanced chitosan beads-supported Fe(0)-nanoparticles for removal of heavy metals from electroplating wastewater in permeable reactive barriers.  

UK PubMed Central (United Kingdom)

The removal of heavy metals from electroplating wastewater is a matter of paramount importance due to their high toxicity causing major environmental pollution problems. Nanoscale zero-valent iron (NZVI) became more effective to remove heavy metals from electroplating wastewater when enhanced chitosan (CS) beads were introduced as a support material in permeable reactive barriers (PRBs). The removal rate of Cr (VI) decreased with an increase of pH and initial Cr (VI) concentration. However, the removal rates of Cu (II), Cd (II) and Pb (II) increased with an increase of pH while decreased with an increase of their initial concentrations. The initial concentrations of heavy metals showed an effect on their removal sequence. Scanning electron microscope images showed that CS-NZVI beads enhanced by ethylene glycol diglycidyl ether (EGDE) had a loose and porous surface with a nucleus-shell structure. The pore size of the nucleus ranged from 19.2 to 138.6 ?m with an average aperture size of around 58.6 ?m. The shell showed a tube structure and electroplating wastewaters may reach NZVI through these tubes. X-ray photoelectron spectroscope (XPS) demonstrated that the reduction of Cr (VI) to Cr (III) was complete in less than 2 h. Cu (II) and Pb (II) were removed via predominant reduction and auxiliary adsorption. However, main adsorption and auxiliary reduction worked for the removal of Cd (II). The removal rate of total Cr, Cu (II), Cd (II) and Pb (II) from actual electroplating wastewater was 89.4%, 98.9%, 94.9% and 99.4%, respectively. The findings revealed that EGDE-CS-NZVI-beads PRBs had the capacity to remediate actual electroplating wastewater and may become an effective and promising technology for in situ remediation of heavy metals.

Liu T; Yang X; Wang ZL; Yan X

2013-11-01

147

Aqueous heavy metals removal by adsorption on amine-functionalized mesoporous silica.  

Science.gov (United States)

Amino functional mesoporous silica SBA-15 materials have been prepared to develop efficient adsorbents of heavy metals in wastewater. Functionalization with amino groups has been carried out by using two independent methods, grafting and co-condensation. Three organic moieties have been selected to incorporate the active amino sites: aminopropyl (H(2)N-(CH(2))(3)-), [2-aminoethylamino]-propyl (H(2)N-(CH(2))(2)-NH-(CH(2))(3)-) and [(2-aminoethylamino)-ethylamino]-propyl (H(2)N-(CH(2))(2)-NH-(CH(2))(2)-NH-(CH(2))(3)-). Materials have been characterized by XRD, nitrogen sorption measurements and chemical analysis. We have found that all materials preserve the mesoscopic order and exhibit suitable textural properties and nitrogen contents to act as potential adsorbents. Metal removal from aqueous solution has been examined for Cu(II), Ni(II), Pb(II), Cd(II), and Zn(II); adsorption performances of materials prepared by the two functionalization methods have been compared. In addition, copper adsorption process has been thoroughly studied from both kinetic and equilibrium points of view for some selected materials. Aqueous Cu(II) adsorption rates show that the overall process is fast and the time evolution can be successfully reproduced with a pseudo-second-order kinetic model. Whole copper adsorption isotherms have been obtained at 25 degrees C. Significant maximum adsorption capacities have been found with excellent behavior at low concentration. PMID:18675509

Aguado, José; Arsuaga, Jesús M; Arencibia, Amaya; Lindo, Montaña; Gascón, Victoria

2008-06-28

148

Removal of heavy metals from industrial effluent using Pinus roxburghii leaves as biosorbent: equilibrium modelling.  

UK PubMed Central (United Kingdom)

In the present study, biosorption capability of pine (Pinus roxburghii) leaves for the removal Cr(6+), Cu(2+), Fe(2+) and Zn(2+) ions, present in brass and electroplating industry effluent, were investigated with respect to different adsorbent doses, contact time and pH. Heavy metals concentrations were estimated by atomic absorption spectrophotometry. Initial concentration of Cr(6+), Cu(2+), Fe(2+) and Zn(2+) ions in the effluent were found to be 2.741, 4.551, 8.820 and 5.529 mg/L respectively. Biosorption studies revealed that Cr(6+), Cu(2+), Fe(2+) and Zn(2+) showed maximum removal of 99.85, 94.54, 97.10 and 89% at pH 4, 4, 4 and 8, respectively, with 4 g pine leaves when shaken at 150 rpm for 60 min. The applicability of the three equilibrium isotherm models was investigated and the data obtained fitted the three investigated isothermal models in the order: Langmuir > Temkin > Freundlich for all the studied metal ions. The adsorption isotherm coefficients, Qmax, b, Kf, n, at, bt were also calculated. Very high regression correlation coefficients (R(2) > 0.9) were found for Cu(2+), Fe(2+) and Zn(2+); Cr(6+) (Temkin isotherm) when pH (2-8) was varied; Cr(6+), Cu(2+),Fe(2+) and Zn(2+) when contact time (15-60 min) was varied; Cu(2+) (Langmuir isotherm) Fe(2+) (Freundlich and Temkin isotherms) when adsorbent was varied from 2 to 5 g. Results also revealed that among all the studied ions Cr(6+) at varied pH and Fe(2+) at different adsorbent doses satisfy the Temkin and Freundlich isotherm models to describe the biosorption equilibrium by pine (Pinus roxburghii) adsorbent.

Tewari H

2013-01-01

149

Soil treatment to remove uranium and related mixed radioactive heavy metal contaminants. Quarterly report, January--March 1995  

Energy Technology Data Exchange (ETDEWEB)

The objective of this project is to design and develop a physico- chemical treatment process for the removal of uranium and heavy metals from contaminated soil to achieve target contamination levels below 35 pCi/g of soil and a target for non-radioactive heavy metals below concentration levels permissible for release of the soil. Ex- situ pilot-scale soil decontamination and leachate treatment test using Chalk River Chemical Pit soil are nearing completion. Soil decontamination tests using Fernald Incinerator Area soil originally scheduled for February 1995 was postponed to May 1995 as result of unexpected delays in the preparation of two drums of soils.

NONE

1995-05-01

150

Removal Efficiency of Heavy Metals Using Various Resins and Natural Materials  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Heavy metals found in local water are an environmental concern. These metals are potentially harmful since they can bio-accumulate in organisms and have been classified as toxic and/or carcinogenic. In this study, water was collected from a shipyard located on a bayou. Various materials (chitosan...

P.P. Vaughan; M.P. Bruns; C.L. Beck; M. Cochran

151

Influence of zeolite transformation in a homoionic form on the removal of some heavy metal ions from wastewater.  

UK PubMed Central (United Kingdom)

Influence of zeolite-clinoptilolite transformation in a homoionic (Na) form on zeolite ability to immobilize Pb2+, Cd2+, Cu2+, Zn2+ and Ni2+ from single ion and multi-component solutions has been studied. Zeolite in Na form exhibits significantly increased ability to remove Cd2+, Cu2+, and Zn2+ from their single ion and multi-component solutions when the water hardness due to Ca2+ presence is not high. Zeolite pretreatment with NaCl leads to increased rate of heavy metal ions' immobilization, as well as to increased distribution coefficients that are indicative for more complete exchange process. Heavy metal ions are more strongly bound to zeolite pretreated with NaCl, compared to natural zeolite. Heavy metal ions immobilization is due to ion exchange adsorption, both in the case of natural and converted in Na form zeolite. Zeolite pretreatment with NaCl practically does not change zeolite selectivity sequence for the ions investigated.

Panayotova M; Velikov B

2003-03-01

152

Removal of heavy metals from aqueous waste streams using surface-modified nanosized TiO{sub 2} photocatalysts.  

Energy Technology Data Exchange (ETDEWEB)

Titanium dioxide (TiO{sub 2}) colloidal particles ({approximately}45{angstrom}) whose surfaces were modified with chelating agents for photocatalytic removal of heavy-metal ions and their subsequent reduction to metallic form were investigated. Experiments were performed on nanoparticle TiO{sub 2} colloids derivatized with bidentate and tridentate ligands (thiolactic acid [TLA], cysteine, and alanine [ALA]) in batch mode in a photoreactor with 254nm light. We used catalysts designed and synthesized for selective and efficient removal of Pb and Cu with and without added hole scavenger (methanol). Parallel experiments also have been carried out in the dark to study metal ion adsorption properties. Solutions have been filtered to remove TiO{sub 2}, and metal particulates. Both the native solution and the metal deposited on the nanocrystalline TiO{sub 2} particles were analyzed. Results demonstrate that for the case of lead, the most effective TiO{sub 2} surface modifier was TLA (>99% Pb(II) removed from solution). Experiments performed to study Cn removal using TiO{sub 2} colloids modified with alanine showed that copper ions were effectively removed and reduced to metallic form in the presence of methanol.

Meshkov, N. K.

1998-08-27

153

Selectivity in the heavy metal removal by exopolysaccharide-producing cyanobacteria.  

UK PubMed Central (United Kingdom)

AIMS: The aim of this study was to assess the selective removal of Cu(II), Cr(III) and Ni(II) by strains of exopolysaccharide (EPS)-producing cyanobacteria, and to investigate the interaction of sorption in solutions with multiple-metals. METHODS AND RESULTS: Nine EPS-producing cyanobacteria were tested for their ability to remove Cr, Cu and Ni in both single- and multiple-metal solutions. In the single-metal solutions, some of the strains showed very high values of metal uptake, however, only two of them showed the capability to selectively remove one or two of the metals present in the multiple-metal solutions. In multi-metal systems, the binding process was either noninteractive, synergistic or competitive between metal ions for different strains of cyanobacteria. CONCLUSIONS: Cyanothece 16Som 2 showed significantly greater sorptive capacity for Cu (1.5-20x) and Cr (2-50x) than all other strains tested. The Nostoc PCC 7936 strain showed high specific and almost exclusive selectivity towards Cu, which suggests its use aimed at recovering this metal from multiple-metal solutions. SIGNIFICANCE AND IMPACT OF THE STUDY: To find out microbial sorbents with good metal selectivity may be very useful for building up processes aimed to recover valuable metals from industrial wastewaters.

Micheletti E; Colica G; Viti C; Tamagnini P; De Philippis R

2008-07-01

154

The Use of Microwave Derived Activated Carbon for Removal of Heavy Metal in Aqueous Solution  

Directory of Open Access Journals (Sweden)

Full Text Available Palm oil processing waste which is palm oil kernel shell (POKS) was converted to activated carbon (POKS AC) through 7 min microwave pyrolysis at temperature 270 °C followed by chemical activation using NaOH and HCl. The adsorption study on Ni(II), Cu(II) and Cr(IV) was conducted to evaluate the efficiency of the prepared activated carbon to remove heavy metal. The adsorption capacity was determined as a function of adsorbate initial concentration and adsorbent dosage. Based on Langmuir isotherm, Ni(II) showed highest adsorption capacity of 40.98 mg/g, followed by Cr(IV) and Cu(II) with adsorption capacity of 40.60 mg/g and 13.69 mg/g, respectively. Cr(IV) and Cu(II) showed better fitting to Freundlich isotherm model with high correlation regression indicating the applicability of heterogeneous adsorption. Ni(II) show better fitting with Langmuir isotherm that indicate monolayer coverage. The use of POKS AC is not only effective for adsorption of Cr(IV), Ni(II) and Cu(II) in aqueous solution but also helps to overcome the over abundance of POKS waste problem.

Rafeah Wahi; Herman Senghie

2011-01-01

155

Sewage sludge ash to phosphorus fertiliser (II): Influences of ash and granulate type on heavy metal removal.  

UK PubMed Central (United Kingdom)

Ashes from monoincineration of sewage sludge suggest themselves as an ideal base for inorganic fertiliser production due to their relatively high phosphorus (P)-content. However, previously they need to be detoxified by reducing their heavy metal content. The core process considered in this paper consists of three steps: mixing of the ashes with suitable chlorine-containing additives, granulation of the mixture and thermochemical treatment in a rotary kiln. Here relevant heavy metal compounds are first transformed into volatile species with the help of the additives and then evaporated from the granules. In this study two chemically different ashes and their mixture were agglomerated to two different granulate types, briquettes and rolled pellets. The resulting six different materials were subjected to thermal treatment at different temperatures. The heavy metals examined were Cu and Zn due to their strong dependence on treatment conditions and their relevance concerning thermal treatment of sewage sludge ashes. Besides, the behaviour of Cl and K was monitored and evaluated. The experiments showed that ash type and temperature are more influential on Cl and heavy metal chemistry than granulate type. Temperature is a primary variable for controlling removal in both cases. Cu removal was less dependent on both ash and granulate type than Zn. The Cl utilization was more effective for Cu than for Zn. Depending on the treatment conditions some K could be retained, whereas always all P remained in the treated material. This satisfies the requirement for complete P recycling.

Mattenberger H; Fraissler G; Jöller M; Brunner T; Obernberger I; Herk P; Hermann L

2010-08-01

156

Sewage sludge ash to phosphorus fertiliser (II): Influences of ash and granulate type on heavy metal removal.  

Science.gov (United States)

Ashes from monoincineration of sewage sludge suggest themselves as an ideal base for inorganic fertiliser production due to their relatively high phosphorus (P)-content. However, previously they need to be detoxified by reducing their heavy metal content. The core process considered in this paper consists of three steps: mixing of the ashes with suitable chlorine-containing additives, granulation of the mixture and thermochemical treatment in a rotary kiln. Here relevant heavy metal compounds are first transformed into volatile species with the help of the additives and then evaporated from the granules. In this study two chemically different ashes and their mixture were agglomerated to two different granulate types, briquettes and rolled pellets. The resulting six different materials were subjected to thermal treatment at different temperatures. The heavy metals examined were Cu and Zn due to their strong dependence on treatment conditions and their relevance concerning thermal treatment of sewage sludge ashes. Besides, the behaviour of Cl and K was monitored and evaluated. The experiments showed that ash type and temperature are more influential on Cl and heavy metal chemistry than granulate type. Temperature is a primary variable for controlling removal in both cases. Cu removal was less dependent on both ash and granulate type than Zn. The Cl utilization was more effective for Cu than for Zn. Depending on the treatment conditions some K could be retained, whereas always all P remained in the treated material. This satisfies the requirement for complete P recycling. PMID:20418087

Mattenberger, H; Fraissler, G; Jöller, M; Brunner, T; Obernberger, I; Herk, P; Hermann, L

2010-04-24

157

Heavy metal removal and crude bio-oil upgrading from Sedum plumbizincicola harvest using hydrothermal upgrading process.  

UK PubMed Central (United Kingdom)

The main aim of this study was to separate heavy metals and yield crude bio-oil from a heavy metals hyperaccumulator harvest, Sedum plumbizincicola, through hydrothermal upgrading process. Parameters such as granularity, temperature, pressure, and duration were examined for their effect on the removal efficiency of heavy metals and upgrading efficacy of crude bio-oil. Maximum heavy metal removal efficiency of >99% and crude bio-oil upgrading efficiency of >63% were attained with an 18 mesh (1mm) granularity, and 22.1MPa at 370 degrees C in the presence of 10mg/L additives for 60s. Under these optimized conditions, an oil phase (mostly composed of phenolic hydrocarbons and derivatives), a water phase raffinate containing Zn(2+) (0.39g/L), Pb(2+) (0.10g/L), Cu(2+) (0.16g/L), and a solid phase (the hydrothermal upgrading residue, which completely satisfies the limit set by China legislation related to biosolids disposal, were obtained).

Yang JG

2010-10-01

158

Heavy metal removal and crude bio-oil upgrading from Sedum plumbizincicola harvest using hydrothermal upgrading process.  

Science.gov (United States)

The main aim of this study was to separate heavy metals and yield crude bio-oil from a heavy metals hyperaccumulator harvest, Sedum plumbizincicola, through hydrothermal upgrading process. Parameters such as granularity, temperature, pressure, and duration were examined for their effect on the removal efficiency of heavy metals and upgrading efficacy of crude bio-oil. Maximum heavy metal removal efficiency of >99% and crude bio-oil upgrading efficiency of >63% were attained with an 18 mesh (1 mm) granularity, and 22.1 MPa at 370 degrees C in the presence of 10 mg/L additives for 60 s. Under these optimized conditions, an oil phase (mostly composed of phenolic hydrocarbons and derivatives), a water phase raffinate containing Zn2+ (0.39 g/L), Pb2+ (0.10 g/L), Cu2+ (0.16 g/L), and a solid phase (the hydrothermal upgrading residue, which completely satisfies the limit set by China legislation related to biosolids disposal, were obtained). PMID:20578290

Yang, Jian-guang

2010-10-01

159

Sewage sludge ash to phosphate fertilizer by chlorination and thermal treatment: residence time requirements for heavy metal removal.  

Science.gov (United States)

Heavy metal removal from sewage sludge ash can be performed by mixing the ash with environmentally compatible chlorides (e.g. CaCl2 or MgCl2) and water, pelletizing the mixture and treating the pellets in a rotary reactor at about 1000 degrees C. Thermogravimetry-mass spectroscopy, muffle oven tests (500-1150 degrees C) and investigations in a laboratory-scale rotary reactor (950-1050 degrees C, residence time 1-25 min) were carried out. In the rotary reactor, up to 97% of Cu, 95% Pb and 95% Zn can be removed at 1050 degrees C. As Cl release starts from 400 degrees C (obtained from thermogravimetry-mass spectrometry experiments), heavy metals are already removed partially within the heating period. This heavy metal removal can be described as being similar to a first-order rate law. To meet the limit values specified in the Austrian and German fertilizer ordinances, residence times of the order of minutes are sufficient at 950 degrees C. PMID:23393980

Nowak, Benedikt; Wegerer, Harald; Aschenbrenner, Philipp; Rechberger, Helmut; Winter, Franz

160

Sewage sludge ash to phosphate fertilizer by chlorination and thermal treatment: residence time requirements for heavy metal removal.  

UK PubMed Central (United Kingdom)

Heavy metal removal from sewage sludge ash can be performed by mixing the ash with environmentally compatible chlorides (e.g. CaCl2 or MgCl2) and water, pelletizing the mixture and treating the pellets in a rotary reactor at about 1000 degrees C. Thermogravimetry-mass spectroscopy, muffle oven tests (500-1150 degrees C) and investigations in a laboratory-scale rotary reactor (950-1050 degrees C, residence time 1-25 min) were carried out. In the rotary reactor, up to 97% of Cu, 95% Pb and 95% Zn can be removed at 1050 degrees C. As Cl release starts from 400 degrees C (obtained from thermogravimetry-mass spectrometry experiments), heavy metals are already removed partially within the heating period. This heavy metal removal can be described as being similar to a first-order rate law. To meet the limit values specified in the Austrian and German fertilizer ordinances, residence times of the order of minutes are sufficient at 950 degrees C.

Nowak B; Wegerer H; Aschenbrenner P; Rechberger H; Winter F

2012-10-01

 
 
 
 
161

Applicability of agricultural waste and by-products for adsorptive removal of heavy metals from wastewater.  

Science.gov (United States)

This critical review discusses the potential use of agricultural waste based biosorbents (AWBs) for sequestering heavy metals in terms of their adsorption capacities, binding mechanisms, operating factors and pretreatment methods. The literature survey indicates that AWBs have shown equal or even greater adsorption capacities compared to conventional adsorbents. Thanks to modern molecular biotechnologies, the roles of functional groups in biosorption process are better understood. Of process factors, pH appears to be the most influential. In most cases, chemical pretreatments bring about an obvious improvement in metal uptake capacity. However, there are still several gaps, which require further investigation, such as (i) searching for novel, multi-function AWBs, (ii) developing cost-effective modification methods and (iii) assessing AWBs under multi-metal and real wastewater systems. Once these challenges are settled, the replacement of traditional adsorbents by AWBs in decontaminating heavy metals from wastewater can be expected in the future. PMID:24045220

Nguyen, T A H; Ngo, H H; Guo, W S; Zhang, J; Liang, S; Yue, Q Y; Li, Q; Nguyen, T V

2013-08-28

162

Investigation of novel adsorptive-separation methods for removal of trace heavy metals from polluted areas. Technical report  

Energy Technology Data Exchange (ETDEWEB)

The removal of trace amounts of cadmium and zinc from waste-water samples from the Bunker Hill mine and from synthetic waste-waters was evaluated. The heavy metals were chelated with the surfactants sodium lauryl sulfate, sodium lauryl benzene sulfate, and cetyl pyridinium chloride. The chelated metals were then separated by the generation of a form with sparged air or dissolved air. As much as 95% of the metal entering the foam generation unit was removed and carried out with the foam. The foam constituted about 25% of the feed. The removal efficiency was correlated with feed flow rate and foam drainage height by means of a simple equilibrium model. Qualitative predictions based upon the model fit the experimental results, although quantitative agreement was not good. Recommendations for further experimental work are presented.

Carleson, T.E.; Moussavi, M.

1988-05-01

163

Removal of some heavy metals from industrial waste water using polyacrylamide ferric antimonate as new ion exchange material  

International Nuclear Information System (INIS)

[en] Composite ion exchangers consist of one or more ion exchangers combined with another material, which can be inorganic or organic and may it be an ion exchanger. The reason for manufacturing a composite material is to produce a granular material, with sufficient strength for column use, from ion exchangers that do not form, or only form weak, granules themselves. Attempts in this study are focused to prepare composite ion exchangers for treatment of wastewater. Heavy metals when present in water in concentrations exceeding the permitted limits are injurious to the health. Hence, it is very important to treat such waters to remove the metal ions present before it is supplied for any useful purpose. Therefore, many investigations have studied to develop more effective process to treat such waste stream. Ion-exchange has been widely adopted in heavy metal containing wastewater and most of the ion-exchangers (i.e. ion-exchange media) currently being used are commercially mass-produced organic resins.Therefore, the main aim of this work is directed to find the optimum conditions for removal of some heavy metals from industrial waste water.1-Preparation of polyacrylamide ferric antimonate composite.2-Characterization of the prepared exchanger using IR spectra, X-ray diffraction pattern, DTA and TG analyses.3-Chemical stability, capacity and equilibrium measurements will be determined on the materials using at different conditions (ph heating temperature and reaction temperature).4-Kinetic studies of some heavy metals.5-Ion exchange isotherm.6-Breakthrough curves for removal of the investigated metal ions on the prepared exchanger under certain condition.

2011-01-01

164

Enzyme-based glucose delivery: a possible tool for biosorbent preparation for heavy metal removal from polluted environments.  

Science.gov (United States)

This study was performed to examine the influence of the controlled glucose supply technology, EnBase(®) Flo, on growth and heavy metals uptake capacity of two Bacillus strains isolated from food industry wastewater. Bacillus sp. growth on EnBase Flo (mineral salt complex medium containing starch-derived polymer as substrate) was examined in 24 deep well plates, controlling the glucose amount release by adding two amyloglucosidase concentrations (3 and 6 UL(-1)). Adsorption of the heavy metals Zn(2+), Cd(2+) and Pb(2+) was assessed in a single component system using synthetic metal solutions and as a function of the initial concentration of adsorbate, equilibrium time and removal efficiency. The Langmuir and Freundlich adsorption models were used for the mathematical description of the biosorption equilibrium and isotherm constants. A pseudo second-order model was applied to describe the uptake rate for two isolates. The EnBase(®) Flo technology improved the cells growth over ten times after 24 h of fed-batch cultivation. The EnBase(®) Flo technology improved the Cd(2+) and Pb(2+) uptake capacity of the bacterial strains by approximately 55 and 44 %, respectively. The biosorption of each metal was fairly rapid (within 30 min), which could be an advantage for large scale treatment of contaminated sites. This initial study may be a basis for future developments to apply EnBase Flo for the biomass production used further as biosorbent for heavy metal removal from aqueous solutions. PMID:23456253

Palela, Mihaela; Bahrim, Gabriela Elena; Glazyrina, Julia; Brand, Eva; Neubauer, Peter

2013-03-03

165

Enzyme-based glucose delivery: a possible tool for biosorbent preparation for heavy metal removal from polluted environments.  

UK PubMed Central (United Kingdom)

This study was performed to examine the influence of the controlled glucose supply technology, EnBase(®) Flo, on growth and heavy metals uptake capacity of two Bacillus strains isolated from food industry wastewater. Bacillus sp. growth on EnBase Flo (mineral salt complex medium containing starch-derived polymer as substrate) was examined in 24 deep well plates, controlling the glucose amount release by adding two amyloglucosidase concentrations (3 and 6 UL(-1)). Adsorption of the heavy metals Zn(2+), Cd(2+) and Pb(2+) was assessed in a single component system using synthetic metal solutions and as a function of the initial concentration of adsorbate, equilibrium time and removal efficiency. The Langmuir and Freundlich adsorption models were used for the mathematical description of the biosorption equilibrium and isotherm constants. A pseudo second-order model was applied to describe the uptake rate for two isolates. The EnBase(®) Flo technology improved the cells growth over ten times after 24 h of fed-batch cultivation. The EnBase(®) Flo technology improved the Cd(2+) and Pb(2+) uptake capacity of the bacterial strains by approximately 55 and 44 %, respectively. The biosorption of each metal was fairly rapid (within 30 min), which could be an advantage for large scale treatment of contaminated sites. This initial study may be a basis for future developments to apply EnBase Flo for the biomass production used further as biosorbent for heavy metal removal from aqueous solutions.

Palela M; Bahrim GE; Glazyrina J; Brand E; Neubauer P

2013-03-01

166

Determination of Heavy Metal Removal Efficiency of Chrysopogon zizanioides (Vetiver) using Textile Wastewater Contaminated Soil  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A pot culture study was conducted using textile wastewater contaminated soil which was amended with Vermicompost (VC) in various proportions for a period of two months. The plant used for the study was Chrysopogon zizanioides (Vetiver) to investigate the accumulation of heavy metals in their ...

S. Jayashree; J. Rathinamala; P. Lakshmanaperumalsamy

167

Studies on sorption, desorption, regeneration and reuse of sugar-beet pectin gels for heavy metal removal  

International Nuclear Information System (INIS)

This work reports the effectiveness of sugar-beet pectin xerogels for the removal of heavy metals (cadmium, lead and copper) after multiple batch sorption-desorption cycles, with and without a gels regeneration step. Metals were recovered from xerogel beads without destroying their sorption capability and the beads were successfully reused (nine cycles) without significant loss in both biosorption capacity and biosorbent mass. Metals uptake levelled off or increased after using a 1 M CaCl2 regeneration step after each desorption. Calcium, as a regenerating agent, increased the stability and reusability of the gels repairing the damage caused by the acid and removing the excess protons after each elution providing new binding sites. Because of their excellent reusability, pectin xerogels are suitable for metal remediation technologies.

2010-06-15

168

Studies on sorption, desorption, regeneration and reuse of sugar-beet pectin gels for heavy metal removal  

Energy Technology Data Exchange (ETDEWEB)

This work reports the effectiveness of sugar-beet pectin xerogels for the removal of heavy metals (cadmium, lead and copper) after multiple batch sorption-desorption cycles, with and without a gels regeneration step. Metals were recovered from xerogel beads without destroying their sorption capability and the beads were successfully reused (nine cycles) without significant loss in both biosorption capacity and biosorbent mass. Metals uptake levelled off or increased after using a 1 M CaCl{sub 2} regeneration step after each desorption. Calcium, as a regenerating agent, increased the stability and reusability of the gels repairing the damage caused by the acid and removing the excess protons after each elution providing new binding sites. Because of their excellent reusability, pectin xerogels are suitable for metal remediation technologies.

Mata, Y.N. [Department of Materials Science and Metallurgical Engineering, Complutense University of Madrid, Ciudad Universitaria s/n 28040 Madrid (Spain); Blazquez, M.L., E-mail: mlblazquez@quim.ucm.es [Department of Materials Science and Metallurgical Engineering, Complutense University of Madrid, Ciudad Universitaria s/n 28040 Madrid (Spain); Ballester, A.; Gonzalez, F.; Munoz, J.A. [Department of Materials Science and Metallurgical Engineering, Complutense University of Madrid, Ciudad Universitaria s/n 28040 Madrid (Spain)

2010-06-15

169

Removal of heavy metals from acid mine drainage (AMD) using coal fly ash, natural clinker and synthetic zeolites.  

UK PubMed Central (United Kingdom)

Acid mine drainage (AMD) is a widespread environmental problem associated with both working and abandoned mining operations, resulting from the microbial oxidation of pyrite in presence of water and air, affording an acidic solution that contains toxic metal ions. The generation of AMD and release of dissolved heavy metals is an important concern facing the mining industry. The present study aimed at evaluating the use of low-cost sorbents like coal fly ash, natural clinker and synthetic zeolites to clean-up AMD generated at the Parys Mountain copper-lead-zinc deposit, Anglesey (North Wales), and to remove heavy metals and ammonium from AMD. pH played a very important role in the sorption/removal of the contaminants and a higher adsorbent ratio in the treatment of AMD promoted the increase of the pH, particularly using natural clinker-based faujasite (7.70-9.43) and the reduction of metal concentration. Na-phillipsite showed a lower efficiency as compared to that of faujasite. Selectivity of faujasite for metal removal was, in decreasing order, Fe>As>Pb>Zn>Cu>Ni>Cr. Based on these results, the use of these materials has the potential to provide improved methods for the treatment of AMD.

Ríos CA; Williams CD; Roberts CL

2008-08-01

170

Removal of heavy metals from acid mine drainage (AMD) using coal fly ash, natural clinker and synthetic zeolites.  

Science.gov (United States)

Acid mine drainage (AMD) is a widespread environmental problem associated with both working and abandoned mining operations, resulting from the microbial oxidation of pyrite in presence of water and air, affording an acidic solution that contains toxic metal ions. The generation of AMD and release of dissolved heavy metals is an important concern facing the mining industry. The present study aimed at evaluating the use of low-cost sorbents like coal fly ash, natural clinker and synthetic zeolites to clean-up AMD generated at the Parys Mountain copper-lead-zinc deposit, Anglesey (North Wales), and to remove heavy metals and ammonium from AMD. pH played a very important role in the sorption/removal of the contaminants and a higher adsorbent ratio in the treatment of AMD promoted the increase of the pH, particularly using natural clinker-based faujasite (7.70-9.43) and the reduction of metal concentration. Na-phillipsite showed a lower efficiency as compared to that of faujasite. Selectivity of faujasite for metal removal was, in decreasing order, Fe>As>Pb>Zn>Cu>Ni>Cr. Based on these results, the use of these materials has the potential to provide improved methods for the treatment of AMD. PMID:18221835

Ríos, C A; Williams, C D; Roberts, C L

2007-12-14

171

Poly(vinyl pyridine-poly ethylene glycol methacrylate-ethylene glycol dimethacrylate) beads for heavy metal removal  

International Nuclear Information System (INIS)

Poly(vinyl pyridine-poly ethylene glycol methacrylate-ethylene glycol dimethacrylate) [poly(VP-PEGMA-EGDMA)] beads with an average size of 30-100 ?m were prepared by suspension polymerization. Poly(VP-PEGMA-EGDMA) beads were characterized by swelling studies, scanning electron microscopy (SEM), elemental analysis, Fourier Transform Infrared Spectroscopy (FTIR). The beads with a swelling ratio of 65% were used for the heavy metal removal studies. Chelation capacity of the beads for the selected metal ions, i.e., Pb(II), Cd(II), Cr(III) and Cu(II) were investigated in aqueous media containing different amounts of these ions (5-80 mg/l) and at different pH values (2.0-10.0). The maximum chelation capacities of the poly(VP-PEGMA-EGDMA) beads were 18.23 mg/g for Pb(II), 16.50 mg/g for Cd(II), 17.38 mg/g for Cr(III) and 18.25 mg/g for Cu(II). The affinity order on mass basis was observed as follows: Cu(II) > Pb(II) > Cr(III) > Cd(II). pH significantly affected the chelation capacity of VP incorporated beads. Heavy metal adsorption on the poly(PEGMA-EGDMA) control microspheres was negligible. Regeneration of the chelating beads was easily performed with 0.1 M HNO3. It was shown that these beads can be used effectively for heavy metal removal from aqueous solutions with repeatedly adsorption-desorption operations. These features show that poly(VP-PEGMA-EGDMA) beads are potential candidate sorbent for heavy metal removal

2008-06-30

172

Physical Characterization of Prepared and Spent CFA/PFA/RHA Sorbents in Removing Heavy Metals and Dyes  

Directory of Open Access Journals (Sweden)

Full Text Available High concentration of heavy metals and dyes creates health and environmental problems. Different types of treatment have been applied to remove these pollutants. In this study, physical characterization of CFA/PFA/RHA sorbent has been investigated to obtain a better understanding of adsorption process in removing heavy metals and dye. The sorbents from Coal Fly Ash (CFA), Palm oil Fuel Ash (PFA) and Rice Husk Ash (RHA) were prepared using water hydration method, sol-gel method and activation by NaOH method. The prepared sorbents were used to remove single components of zinc (Zn2+), nickel (Ni2+), iron (Fe2+) and brilliant green dye from synthetic wastewater. The CFA/PFA/RHA sorbent prepared from sol-gel method showed high adsorption efficiency. From the particle size distribution analysis it was shown that the sorbents have a variation as a result of the reaction during the preparation of sorbent and treatment processes. Higher BET specific surface area was obtained for sorbent prepared from water hydration method. The surface morphology of the sorbents revealed the structure of CFA/PFA/RHA sorbent before and after the adsorption processes. This study shows that physical characteristics of CFA/PFA/RHA sorbent affecting the adsorption of heavy metals and dye.

I. Dahlan; S. Ismail

2012-01-01

173

Hydrogen peroxide modification enhances the ability of biochar (hydrochar) produced from hydrothermal carbonization of peanut hull to remove aqueous heavy metals: Batch and column tests  

Science.gov (United States)

Experimental and modeling investigations were conducted to examine the effect of hydrogen peroxide treatment on hydrothermally produced biochar (hydrochar) from peanut hull to remove aqueous heavy metals. Characterization measurements showed that hydrogen peroxide modification increased the oxygen-c...

174

Removal of heavy metals of used oils lubricants by biosorption; Remocao de metais pesados de oleo lubrificantes usados por biossorcao  

Energy Technology Data Exchange (ETDEWEB)

The used lube oils when thrown directly in the environment (water bodies, sewerage nets, soils) or when burned in a non-controlled way, causes serious problems to the environment. Used lube oils contain high levels of hydrocarbons and heavy metals, of which Iron (Fe), Copper (Cu), Lead (Pb), Nickel (Ni) and Chrome (Cr) are the most representative. Due to these problems and to the high consumption of energy in the re-refining process, came the interest of studying a new methodology for removing those heavy metals from discarded automotive lube oil through the process of biosorption. A type of heavy lube oil used in a bus fleet was chosen and it was characterized in order to find out which metals it contained and its concentration. Then the bio-solvent material was prepared, in this case, the pheophyta seaweed Sargassum Sp. For the biosorption study, some preliminary tests using Sargassum Sp protonated with HCl 0,06 M and without protonation were run. The purpose of using protonated and non-protonated biosorbent was to verify the process efficiency. It was observed that for metal with high level of concentration the protonated biosorbent was more efficient, while for metals with lower concentrations the non-protonated biosorbent was more efficient. (author)

Moreira, Albina da Silva [Rio Grande do Norte Univ., Natal, RN (Brazil). Dept. de Engenharia Quimica. Programa de Pos-graduacao em Engenharia Quimica]. E-mail: albina@eq.ufrn.br; Macedo, Gorete Ribeiro de; Duarte, Marcia Maria Lima [Universidade Federal do Rio Grande do Norte, Natal, RN (Brazil)]. E-mail: marcia@eq.ufrn.br; gomacedo@eq.ufrn.br

2003-07-01

175

Kinetics of heavy metal ions removal by use of natural zeolite.  

UK PubMed Central (United Kingdom)

Kinetics of the uptake of cadmium, lead, copper, nickel and zinc ions from single ion solutions and from their mixture by zeolitic rock has been studied. Removal of ions obeyed the kinetic equation for adsorption. Corresponding adsorption constants and distribution coefficients were determined for each metal ion uptake from single ion solution or mixture. An attempt was made to explain zeolite selectivity to different metal ions and the influence of water hardness on the uptake in terms of metal ionic radii and enthalpy of hydration. It was found that lead ions were strongly immobilized by the zeolite investigated, both from single ion and mixed solutions, as well as from soft and hard water.

Panayotova M; Velikov B

2002-01-01

176

An analysis of manganese as an indicator for heavy metal removal in passive treatment using laboratory spent mushroom compost columns  

Energy Technology Data Exchange (ETDEWEB)

The National Pollution Discharge Elimination System (NPDES) dictates removal of manganese in mine drainage to less than 4 mg/1 daily or less than 2 mg/1 on a monthly average. Owing to its high solubility at low and circumneutral pH, removal of manganese is often the most difficult of the NPDES discharge standards. This has lead to the use of Mn(II) as a surrogate for metal removal. However, recent studies concluded that zinc or nickel may be more appropriate indicators for removal of other metals. Previous field studies showed zinc removal to be highly correlated to the removal of copper, cobalt, and nickel in a sulfate reducing subsurface loaded wetland, whereas manganese removal was poorly correlated. The objective of this study was to evaluate zinc and manganese retention under sulfate reducing conditions in bench scale columns containing fresh spent mushroom compost. Column effluent data were analyzed using an EPA geochemical computer model (MINTEQ) over the pH range of 6.0 to 6.8. Under these conditions, zinc and manganese displayed distinctly reactivities. Zn(II) was supersaturated with respect to ZnS{sub s} and the Zn(HS){sub 2}{degree} and Zn(HS){sub 3}{sup minus} complexes dominated solubility. Soluble zinc concentrations were inversely correlated to sulfide. Mn(II) remained as soluble Mn{sup +2}. During early column operation at pH > 7, MnCO{sup 3(s)} was supersaturated. Manganese concentrations did not correlate with pH or sulfide. Given these fundamental differences in removal mechanisms between Zn and Mn under sulfate reducing conditions, the use of manganese removal as a surrogate for heavy metal removal in passive treatment of mine drainage seems unjustified.

Jacobson, B.A.; Unz, R.F.; Dempsey, B.A.

1999-07-01

177

Hierarchically Structured Manganese Oxide-Coated Magnetic Nanocomposites for Efficient Removal of Heavy Metal Ions from Aqueous Systems.  

UK PubMed Central (United Kingdom)

In this study, hierarchical MnO2-coated magnetic nanocomposite (Fe3O4/MnO2) was synthesized by a mild hydrothermal process, and then its application for removing heavy metal ions from contaminated water systems was examined. Structural characterization showed that Fe3O4 nanoparticle core was coated with amorphous MnO2 shell with flowerlike morphology. The as-prepared nanocomposite had a large surface area and high magnetic saturation value, which ensure the good sorption ability and convenience of separation. The Fe3O4/MnO2 exhibited a greatly improved removal capacity toward four different heavy metals (Cd(II), Cu(II), Pb(II), Zn(II)) compared to unmodified Fe3O4 nanoparticles. The adsorption property of Fe3O4/MnO2 was studied with Cd(II) in more detail. The sorption equilibrium data were well fitted to the Langmuir model, and the maximum adsorption capacity toward Cd(II) was 53.2 mg•g-1. The Fe3O4/MnO2 retained over 80% of adsorption capacity under various solution conditions that are typically encountered in natural waters. This nanocomposite was easily recovered and reused through consecutive adsorption-desorption experiments with the assistance of external magnetic field. Overall findings propose that Fe3O4/MnO2 could be used as an effective recyclable adsorbent for heavy metal ions.

Kim EJ; Lee CS; Chang YY; Chang YS

2013-09-01

178

Heavy metal removal in phytofiltration and phycoremediation: the need to differentiate between bioadsorption and bioaccumulation.  

UK PubMed Central (United Kingdom)

Phytoremediation and phycoremediation are cost-effective and environmentally sound technologies for the treatment of polluted streams and wastewaters contaminated with metals. Currently, the most commonly used parameter to assess the metal uptake of biomass is (q) expressed as mg metal g dry weight(-1). By contrast, the bioconcentration factor (BCF) is one of the most widely used factors to evaluate the metal uptake capacity of macrophytes. However, both parameters the metal uptake (q) and the BCF cannot be applied to differentiate between the ability of live plants or photosynthetic microorganisms to adsorb the metal onto their surface through passive mechanisms or to accumulate the contaminant at intracellular level through metabolically active mechanisms. This mini review has the objective of discussing the need to differentiate between bioadsorption and bioaccumulation of metals in live plants and photosynthetic microorganisms used in phytofiltration and phycoremediation processes, respectively. The use of two specific factors, the bioadsorption factor (BAF) and the intracellular accumulation factor (IAF) that have been previously reported in order to make a clear differentiation between these two metal removal mechanisms in Salvinia minima and Leptolyngbya crossbyana is highlighted. It is suggested that the BAF and the IAF can be used in phytofiltration wetlands and phycoremediation lagoons, where there is the need of specific information indicating the fate of the metal in order to gain information about possible removal mechanisms. These factors could also provide a tool to decide whether it is possible to harvest the biomass and to recover a fair amount of metal adsorbed onto the surface by means of desorbent agents. A critical assessment of the use of EDTA as desorbent agent is also included.

Olguín EJ; Sánchez-Galván G

2012-11-01

179

Determination of Heavy Metal Removal Efficiency of Chrysopogon zizanioides (Vetiver) using Textile Wastewater Contaminated Soil  

Directory of Open Access Journals (Sweden)

Full Text Available A pot culture study was conducted using textile wastewater contaminated soil which was amended with Vermicompost (VC) in various proportions for a period of two months. The plant used for the study was Chrysopogon zizanioides (Vetiver) to investigate the accumulation of heavy metals in their roots. Physico-chemical parameters like pH, EC, TKN, P, K, TOC and metals like Pb, Cd and Cu and microbial population of the textile wastewater contaminated soil were analyzed initially (0 day) and finally (60th day). The growth parameters of vetiver like root length, shoot length, fresh weight and dry weight were also recorded initially and finally. Based on the data C. zizanioides (Vetiver) tolerated and accumulated the greatest amount of heavy metals. C. zizanioides could uptake more lead than the other metals. The effect of vermicompost on the growth of C. zizanioides showed that the biomass was increased when the vermicompost concentration was increased. The microbial population like bacteria, actinomycetes and fungi was more in the rhizosphere soil than in non-rhizosphere soil.

S. Jayashree; J. Rathinamala; P. Lakshmanaperumalsamy

2011-01-01

180

Removal of free and complexed heavy-metal ions by sorbents produced from fly (Musca domestica) larva shells.  

UK PubMed Central (United Kingdom)

Fly larva shells (FLS) are formed as a side product in the biological treatment of organic wastes, and chitin and chitosan produced from the FLS have been used as sorbents for heavy-metal ions. Sorbents are characterised by FT-IR measurements and pH-potentiometric titration and by determination of their surface area, and the content of main elements (C, N, P, S) and ashes. Free metal ions are sorbed best (up to 0.5-0.8 mmol g(-1)) onto chitin and chitosan. The sorption ability for free metal ions of chitin decreases in the order Fe(III) > Cu(II) (Pb(II) > Zn(II). > Ni(II) > Mn(II) and that of chitosan decreases in the order Cu(II) > Mn(II) > Ni(II) > Zn(II) > Pb(II) > Fe(III). The complexed metal ions are sorbed by the FLS up to 0.2-0.4mmol g(-1). The sorption ability for metal ions and ligands depends on pH, concentration of complexed metal ions and the ligand species in the solution. Glycine has the retarding effect on the sorption of Ni(II) and Cu(II) ions, and EDTA enhances the Cu(II) ion sorption. Ni(II) and glycine sorption obeyed the Langmuir isotherm. The observed sorption data show the promising potentialities of the FLS for the heavy-metal removal from the solutions, containing strong complexing agents. Mechanisms for the removal of free and complexed metal ions by chitin, chitosan and the FLS have been discussed.

Gyliene O; Rekertas R; Salkauskas M

2002-09-01

 
 
 
 
181

Crayfish Carapace Micro-powder (CCM): A Novel and Efficient Adsorbent for Heavy Metal Ion Removal from Wastewater  

Directory of Open Access Journals (Sweden)

Full Text Available Crayfish carapace, a plentiful waste in China, was applied to remove divalent heavy metal ions—copper (Cu), cadmium (Cd), zinc (Zn), and lead (Pb)—from wastewater. The adsorption capacities of crayfish carapace micro-powder (CCM) for heavy metal ions were studied with adsorbent dosages ranging from 0.5–2.5 g/L and with initial metal concentrations ranging from 50–250 mg/L. CCM particle size, initial solution pH (from 2.5–6.5), temperature (from 25–65 °C) and calcium level (from 3.5–21.5%) were also varied in batch mode. The results indicated that the adsorption capacity increases with both decreasing particle size and increasing calcium level of the crayfish carapace. The kinetic studies indicated that the adsorption could be complete within 2 h, and that the data correlated with the pseudo-second-order model. CCM recorded maximum uptakes of 200, 217.39, 80, and 322.58 mg/g for Cu, Cd, Zn, and Pb, respectively. The adsorption capacities and removal efficiencies of CCM for metal ions were three-times higher than those of chitin and chitosan extracted from the CCM.

Xiaodong Zheng; Bin Li; Bo Zhu; Rui Kuang; Xuan Kuang; Baoli Xu; Meihu Ma

2010-01-01

182

Fabrication of chelating diethylenetriaminated pan micro and nano fibers for heavy metal removal  

Directory of Open Access Journals (Sweden)

Full Text Available In this study, commercial acrylic fibers were modified with diethylenetriamine to prepare metal chelating fibers. The effects of process parameters on the efficiency of the reaction were investigated. FTIR spectroscopy and TGA analysis were used to confirm the chemical changes made to the fibers during the reaction. The ability of the modified fibers for removal of Pb (II), Cu (II) and Ce (IV) ions from aqueous media was determined. The modified fibers showed a slight decrease in mechanical properties compared to raw ones. Furthermore, the acrylic micro fibers were electrospun to nanofibers and the ability of modified nanofibers for the adsorption of the metal ions was studied.

Abdouss Majid; Shoushtari Mousavi Ahmad; Haji Aminoddin; Moshref Behnam

2012-01-01

183

Heavy metals removal from wastewaters using organic solid waste-rice husk.  

UK PubMed Central (United Kingdom)

In this study, the removal of Cr(III) and Cu(II) from contaminated wastewaters by rice husk, as an organic solid waste, was investigated. Experiments were performed to investigate the influence of wastewater initial concentration, pH of solution, and contact time on the efficiency of Cr(III) and Cu(II) removal. The results indicated that the maximum removal of Cr(III) and Cu(II) occurred at pH 5-6 by rice husk and removal rate increased by increased pH from 1 to 6. It could be concluded that the removal efficiency was enhanced by increasing wastewater initial concentration in the first percentage of adsorption and then decreased due to saturation of rice husk particles. Also according to achieved results, calculated saturation capacity in per gram rice husk for Cr(III) and Cu(II) were 30 and 22.5 mg?g(-1), respectively. The amounts of Cr(III) and Cu(II) adsorbed increased with increase in their contact time. The rate of reaction was fast. So that 15-20 min after the start of the reaction, between 50 and 60 % of metal ions were removed. Finally, contact time of 60 min as the optimum contact time was proposed.

Sobhanardakani S; Parvizimosaed H; Olyaie E

2013-08-01

184

The heavy metal adsorption properties of hydroxyapatite powders synthesized by precipitation reaction method and its applicability for the removal agents of noxious metallic ions in waste water  

Energy Technology Data Exchange (ETDEWEB)

It is well known that hydroxyapatite [(Ca{sub 10})(PO{sub 4}){sub 6}(OH){sub 2}] have an exchangeability for various heavy metal ions in aqueous solution. To evaluate the feasibility of employing the synthetic hydroxyapatite as an eliminatable exchanger for environmentally noxious cations in waste water, the adsorption properties, the removal capacities and the selectivity of the apatites for various cations were investigated in more detailed. The heavy metal cations have been exchanged in calcium part of hydroxyapatite. The order of the degree of amount exchanged of the investigated cations is Pb{sup 2+} > Cd{sup 2+} > Zn{sup 2+} > Ba{sup 2+}. The molar ratios between released Ca{sup 2+} ions and removed divalent metal cations in the reacted solution with hydroxyapatite are roughly close to an integer 1.0, suggesting that an ion-exchange reaction could have played a major role in the removal of heavy metals rather than an adsorption effect. The exchangeability of the hydroxyapatite powder of Ca/P molar ratio 1.67, which have specific surface area of 104.5 m{sup 2} g{sup -}1, appeared to be better than 237.6 {mu}g per g for Pb{sup 2+} ions. The removal capacity of the heavy metal ions varies directly as particle size of hydroxyapatite. All evidences obtained indicate that the synthesized hydroxyapatite powders by precipitation reaction method can be employed as an effective cation exchanger for eliminating noxious ions in waste water even in some improvemental. (author). 23 refs., 7 tabs., 15 figs.

Lee, Mu Seong; Na, Choon Ki; Lee, Mi Suk; Kim, Oak Bae [Chonbuk National Univ., Chonju (Korea, Republic of); Kim, Moon Young [Korea Institute of Geology Mining and Materials, Taejon (Korea, Republic of)

1995-06-01

185

Removal of heavy metals from Water Rinsing of Plating Baths by Electrodialysis  

Directory of Open Access Journals (Sweden)

Full Text Available During the chromic plating of parts, the baths become more and more poor in chromic acid and rich in metallic impurities such as Cu2+, Zn2+, Fe3+ and Cr3+ which makes the bath useless. Also, the water used to rinse parts contains chromic acid and metallic impurities. As it is known that chromic acid is relatively expensive and very toxic, so its recovery has double interest: economic and environmental. Its reuse is possible after removal of metallic impurities. In this work, we studied the possibility of metallic impurities elimination from the chromic acid. The influence of the current density and the circulating solution flow rate on the process efficiency has been studied. The elimination rates obtained in the presence of ion exchange textile are superior to those obtained in the absence of textile. The analysis of the results showed that for the three metallic impurities studied (Cu2+, Fe3+ and Zn2+), the purification rate increases versus the applied current density and solution flow rate. The importance of the elimination of the three metal cations is as the following order: Cu2+ >Zn2+ >Fe3+.

Delimi R.; Boutemine N.; Benredjem Z.

2013-01-01

186

Heavy metal removal from aqueous solution by wasted biomass from a combined AS-biofilm process.  

UK PubMed Central (United Kingdom)

This study evaluated the capability of metal biosorption by wasted biomass from a combined anaerobic-anoxic-oxic (A2O)-biofilm process with simultaneous nitrogen and phosphorus removal. Zinc, cadmium and nickel were rapidly adsorbed in 20 min by the harvested sludge from a continuous-flow pilot-plant. Biosorption equilibrium was then reached in 6h. The biosorption isotherm showed that metal biosorption behavior had fitted well to the Freundlich isotherm, but not Langmuir isotherm. The capacity constants k of Freundlich model for nickel, zinc and cadmium were 0.471, 0.298 and 0.726, respectively; the affinity constants 1/n were 0.444, 0.722 and 0.718, respectively. The order of metal affinity for the wasted biomass was Zn > Cd > Ni, which was in conformity to the other biosorption results with different biological sludge.

Chang WC; Hsu GS; Chiang SM; Su MC

2006-09-01

187

Kinetics of heavy metal ions removal by use of natural zeolite.  

Science.gov (United States)

Kinetics of the uptake of cadmium, lead, copper, nickel and zinc ions from single ion solutions and from their mixture by zeolitic rock has been studied. Removal of ions obeyed the kinetic equation for adsorption. Corresponding adsorption constants and distribution coefficients were determined for each metal ion uptake from single ion solution or mixture. An attempt was made to explain zeolite selectivity to different metal ions and the influence of water hardness on the uptake in terms of metal ionic radii and enthalpy of hydration. It was found that lead ions were strongly immobilized by the zeolite investigated, both from single ion and mixed solutions, as well as from soft and hard water. PMID:11846275

Panayotova, Marinela; Velikov, Borislav

2002-01-01

188

Removal of heavy metals from contaminated water using ethylenediamine-modified green seaweed (Caulerpa serrulata)  

Science.gov (United States)

The demand for clean water is on the increase as the population increases. One of the ways to address the water shortage is to treat the polluted water through removal of the contaminants. The use of adsorbents for pollutant removal is one of the promising methods. Seaweed is an aquatic plant and its sorption ability for selected metals in water was investigated in this study. We report the performance of the seaweed (Caulerpa serrulata) before and after modification with ethylenediamine (EDA), on adsorption of copper, lead and cadmium in aqueous solution. The adsorption capacities for Cu, Cd and Pb were 5.27 mg g-1, 2.12 mg g-1 and 2.16 mg g-1, respectively, with the EDA-modified seaweed, and 3.29 mg g-1, 4.57 mg g-1 and 1.06 mg g-1, with the unmodified weed, respectively. The pH for maximum adsorption was found to be within the range of pH 4-pH 6. In a separate investigation, it was found that 0.1 g of dried seaweed leached 20 mg of dissolved organic carbon (DOC) using 100 ml of distilled-deionised water. The resulting solution was green. The leaching phenomenon contributes to secondary pollution. Modification of the seaweed with EDA reduced the DOC content by half (50%) and also removed the green colouration. Kinetic studies showed that the adsorbent was able to take up to 95% of the metals (in synthetic standard solutions) in less than 10 min. The adsorbed metals were then stripped using a solution of 0.5 M HNO3 indicating that the adsorbent can be regenerated. In addition, the study revealed that modification improved the thermal stability of the adsorbent such that even when the temperature was raised to 1000 °C, more than 80% (compared to <50% for unmodified weed) of the modified adsorbent was not degraded, indicating that modification had a significant influence on the thermal stability of seaweed. The modified seaweed has been shown to have great potential for the removal of metals and DOC in polluted water. The modified adsorbent can therefore be applied for the removal of metals in polluted waters hence suitable for treatment of water for domestic consumption at a point of use.

Mwangi, Isaac W.; Ngila, J. Catherine

189

Molecular Characterization of Some Novel Marine Alicyclobacillus Strains, Capable of Removing Lead from a Heavy Metal Contaminated Sea Spot  

Directory of Open Access Journals (Sweden)

Full Text Available Sea water from heavy metal contaminated area in the Mediterranean, was analyzed for its heavy metal contents and their concentrations. It was observed that lead has the highest concentration (0.48 ppm) among the remaining heavy metal concentrations. Four different Gram-positive, rod-shaped and spore forming Alicyclobacillus (formally Bacillus) isolates were isolated from the same sea spot. Phenotypic characterization of pure cultures were examined for motility, Gram reaction, spore morphology, catalase and oxidase production. Scanning electron micrograph showed that cells of both strains were occurring singly or in short chains. Randomly Amplified Polymorphic DNA (RAPD) analysis showed a great deal of differentiation among the isolates, revealing that each of them has its own DNA fingerprint. A dendrogram showing the genetic similarity among the sea isolates, clustered them into two main groups at 30% of genetic similarity. Partial sequencing of the 16S rDNA of 2, representative isolates revealed that both of them are novel Alicyclobacillus strains S2 and S4. The isolates had the ability to remove lead from contaminated solutions. A promising strain, S4, showed a valuable uptake levels, 64 and 65.3% at 0.5 and 0.9 ppm of pb2+, respectively, after only 2 h of exposure to lead. This strain can be later used efficiently for the bioremediation of lead in contaminated water bodies.

Eman A.H. Mohamed; Nermeen A. ElSersy

2009-01-01

190

Influence of zeolite transformation in a homoionic form on the removal of some heavy metal ions from wastewater.  

Science.gov (United States)

Influence of zeolite-clinoptilolite transformation in a homoionic (Na) form on zeolite ability to immobilize Pb2+, Cd2+, Cu2+, Zn2+ and Ni2+ from single ion and multi-component solutions has been studied. Zeolite in Na form exhibits significantly increased ability to remove Cd2+, Cu2+, and Zn2+ from their single ion and multi-component solutions when the water hardness due to Ca2+ presence is not high. Zeolite pretreatment with NaCl leads to increased rate of heavy metal ions' immobilization, as well as to increased distribution coefficients that are indicative for more complete exchange process. Heavy metal ions are more strongly bound to zeolite pretreated with NaCl, compared to natural zeolite. Heavy metal ions immobilization is due to ion exchange adsorption, both in the case of natural and converted in Na form zeolite. Zeolite pretreatment with NaCl practically does not change zeolite selectivity sequence for the ions investigated. PMID:12680582

Panayotova, M; Velikov, B

2003-03-01

191

Removal of heavy metal from industrial wastewater using chitosan coated oil palm shell charcoal  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english This research focuses on understanding biosorption process and developing a cost effective technology for treatment of heavy metals-contaminated industrial wastewater. A new composite biosorbent has been prepared by coating chitosan onto acid treated oil palm shell charcoal (AOPSC). Chitosan loading on the AOPSC support is about 21% by weight. The shape of the adsorbent is nearly spherical with particle diameter ranging 100~150 µm. The adsorption capacity of the com (more) posite biosorbent was evaluated by measuring the extent of adsorption of chromium metal ions from water under equilibrium conditions at 25ºC. Using Langmuir isotherm model, the equilibrium data yielded the following ultimate capacity values for the coated biosorbent on a per gram basis of chitosan: 154 mg Cr/g. Bioconversion of Cr (VI) to Cr (III) by chitosan was also observed and had been shown previously in other studies using plant tissues and mineral surfaces. After the biosorbent was saturated with the metal ions, the adsorbent was regenerated with 0.1 M sodium hydroxide. Maximum desorption of the metal takes place within 5 bed volumes while complete desorption occurs within 10 bed volumes. Details of preparation of the biosorbent, characterization, and adsorption studies are presented. Dominant sorption mechanisms are ionic interactions and complexation.

Saifuddin M, Nomanbhay; Kumaran, Palanisamy

2005-04-01

192

Removal of heteroatoms and metals from heavy oils by bioconversion processes  

Energy Technology Data Exchange (ETDEWEB)

Biocatalysts, either appropriate microorganisms or isolated enzymes, will be used in an aqueous phase in contact with the heavy oil phase to extract heteroatoms such as sulfur from the oil phase by bioconversion processes. Somewhat similar work on coal processing will be adapted and extended for this application. Bacteria such as Desulfovibrio desulfuricans will be studied for the reductive removal of organically-bound sulfur and bacteria such as Rhodococcus rhodochrum will be investigated for the oxidative removal of sulfur. Isolated bacteria from either oil field co-produced sour water or from soil contaminated by oil spills will also be tested. At a later time, bacteria that interact with organic nitrogen may also be studied. This type of interaction will be carried out in advanced bioreactor systems where organic and aqueous phases are contacted. One new concept of emulsion-phase contacting, which will be investigated, disperses the aqueous phase in the organic phase and is then recoalesced for removal of the contaminants and recycled back to the reactor. This program is a cooperative research and development program with the following companies: Baker Performance Chemicals, Chevron, Energy BioSystems, Exxon, Texaco, and UNOCAL. After verification of the bioprocessing concepts on a laboratory-scale, the end-product will be a demonstration of the technology at an industrial site. This should result in rapid transfer of the technology to industry.

Kaufman, E.N.

1996-06-01

193

The behaviour of ion exchange membranes in the process of heavy metals removal from contaminated soil  

Energy Technology Data Exchange (ETDEWEB)

A novel technique for the remediation of metal contaminated backfill soil, was presented. The technique was based on the ion exchange membrane process combined with the electrokinetic phenomena. A series of experiments were conducted in a lead and nickel contaminated soil. Effluent transported through the soil was collected daily, and the volume and pH of the soil was measured. A set of silver electrode-probes were inserted into the soil between the cathode and the anode to monitor the electrical parameters. Results of the experiments showed that the removal efficiency of nickel from the soil was as high as 95%. The removal of lead was less: 3.3-40% depending on the type of ion exchange textiles and other conditions. The time required for soil treatment decreased which suggested that the process could be cost-efficient in field applications. 6 refs., 4 tabs., 9 figs.

Elektorowicz, M.; Chifrina, R.; Kozak, M.; Hatim, G. [Concordia Univ., Montreal, PQ (Canada). Dept. of Civil Engineering

1996-09-01

194

Chestnut shell as heavy metal adsorbent: Optimization study of lead, copper and zinc cations removal  

International Nuclear Information System (INIS)

The influence of initial cation concentration, temperature and pH was investigated to optimize Pb2+, Cu2+ and Zn2+ removal from aqueous solutions using acid formaldehyde pre-treated chestnut shell as adsorbent. Experiments were planned according to an incomplete 33 factorial experimental design. Under the optimal conditions selected, the metal ion adsorption equilibrium was satisfactorily described by the Langmuir isotherm model. The maximum pre-treated chestnut shell adsorption capacity was obtained for Pb2+ ions, 8.5 mg g-1, and the order of cation affinity was Pb2+ > Cu2+ > Zn2+. A model that considered the effect of axial dispersion was successfully used to describe the fixed-bed adsorption behaviour of Pb2+, Cu2+ and Zn2+ ions at the flow rates essayed. Fourier transform infrared (FTIR) and X-ray photoelectron (XPS) spectroscopies showed that the functional groups involved in metal ions binding included carboxyl, hydroxyl, ether, alcoholic and amino groups.

2009-12-30

195

Removal of heavy-metal pollutants from ground water using a reverse-osmosis/coupled-transport hybrid system  

International Nuclear Information System (INIS)

Two membrane processes - reverse osmosis (RO) and coupled transport (CT) - are useful in removing heavy metals from aqueous solutions and producing purified water. Each process has advantages. RO produces clean water reliably and relatively inexpensively. However, the pollutants are removed nonselectively and cannot be appreciably concentrated. CT removes pollutants selectively and can concentrate them by several orders of magnitude, but CT suffers from limited reliability and performs poorly at low pollutant concentrations. By combining these two unit processes in a hybrid process, it is possible to capitalize on the advantages of each process and to minimize their disadvantages. The RO/CT hybrid process the authors are developing removes more than 98% of the uranium and chromium in a contaminated groundwater stream - reducing concentrations of each pollutant to less than 100 ppb. These pollutants are simultaneously recovered as a concentrate at metal-ion concentrations greater than 1 wt% in relatively pure form. The hybrid process promises to be reliable and to reduce treatment costs below that for costs if either CT or RO were used alone. Even more importantly, the high selectivity of the hybrid process minimizes the volume of waste requiring disposal

1993-01-01

196

Irreversible removal of ecotoxic heavy metals from ash; Zur irreversiblen Ausschaltung des oekotoxischen Schwermetallpotentials von Aschen  

Energy Technology Data Exchange (ETDEWEB)

Power plant waste and residues from biomass treatment (ashes, sludges etc.) may contain heavy metals in concentrations that exceed the specified limits and may present an ecological hazard as they migrate into soil and groundwater. The contribution discusses countermeasures. [German] Abfaelle aus Kraftwerken und Rueckstaende der Behandlung von Biomassen, wie zum Beispiel Aschen, Schlaemmen aus der Verbrennung, Vergasung, Hydrolyse, Vergaerung bzw. der biomechanischen Behandlung von Holz, Altholz oder Stroh, enthalten haeufig eluierbare Anteile von Schwermetallen, die ueber den gesetzlichen Grenzwerten liegen. Aus der Moeglichkeit, dass diese Stoffe bei der Verwertung oder Deponierung ueber den Boden- oder Wasserpfad in die Umwelt gelangen, ergibt sich eine oekologische Gefaehrdung. Diese kann beseitigt werden, wenn es gelingt, diese Schadelemente aus den Abfaellen herauszuloesen oder so fest zu binden, dass sie auf natuerlichem Wege auch nach sehr langen Zeitraeumen nicht freigesetzt werden koennen. (orig.)

Bauermeister, U.; Spindler, H. [Foerdergemeinschaft Oekologische Stoffverwertung e.V., Halle (Germany)

2000-03-01

197

High-density three-dimension graphene macroscopic objects for high-capacity removal of heavy metal ions.  

UK PubMed Central (United Kingdom)

The chemical vapor deposition (CVD) fabrication of high-density three-dimension graphene macroscopic objects (3D-GMOs) with a relatively low porosity has not yet been realized, although they are desirable for applications in which high mechanical and electrical properties are required. Here, we explore a method to rapidly prepare the high-density 3D-GMOs using nickel chloride hexahydrate (NiCl?·6H?O) as a catalyst precursor by CVD process at atmospheric pressure. Further, the free-standing 3D-GMOs are employed as electrolytic electrodes to remove various heavy metal ions. The robust 3D structure, high conductivity (~12?S/cm) and large specific surface area (~560?m²/g) enable ultra-high electrical adsorption capacities (Cd²? ~ 434?mg/g, Pb²?~ 882?mg/g, Ni²? ~ 1,683?mg/g, Cu²? ~ 3,820?mg/g) from aqueous solutions and fast desorption. The current work has significance in the studies of both the fabrication of high-density 3D-GMOs and the removal of heavy metal ions.

Li W; Gao S; Wu L; Qiu S; Guo Y; Geng X; Chen M; Liao S; Zhu C; Gong Y; Long M; Xu J; Wei X; Sun M; Liu L

2013-01-01

198

Removal of Heavy Metals and Organic Contaminants from Wwater by Novel Filtration Methods. Final report  

International Nuclear Information System (INIS)

The removal of hazardous waste, generated by the dismantling of nuclear weapons is a problem that requires urgent attention by the US Department of Energy. Low levels of radioactive contaminants combined with organic solvent residues have leaked from aging containers into the soil and underground water in the surrounding area. Due to the complexity of the problem, it is evident that traditional adsorption methods are ineffective, since the adsorbent tends to saturate with the aqueous component. It has become apparent that a much more aggressive approach is required which involves the use of specially designed materials. We have investigated the potential of solids that combine high surface area/high pore volume and high electrical conductivity, a rare combination of properties found in a single material. In this program we examined the potential of newly developed materials for the trapping of organic solvents within specially engineered cavities without allowing the material to become saturated with water. Catalytically grown carbon nanofibers are a set of novel structures that are produced by the decomposition of selected carbon-containing gases over metal particles. These materials consist of extremely small graphite platelets stacked in various orientations with respect to the fiber axis. Such an arrangement results in a unique structure that is composed of an infinite number of extremely short and narrow pores, suitable for sequestering small molecules. In addition, when the graphene layers are aligned parallel to the fiber axis, an unusual combination of high surface area and low electrical resistivity solids are attained. We have attempted to capitalize on this blend of properties by using such structures for the selective removal of organic contaminants from aqueous streams. Experimental results indicate that nanofibers possessing a structure in which the graphite platelets are aligned perpendicular to the fiber axis and possessing a high degree of structural perfection exhibit superior selective adsorption properties with respect to removal of alcohols from aqueous medial over that displayed by active carbon. Furthermore, we have attempted to take advantage of the high electrical conductivity as well as the high availability of edges, and we have used these materials for the removal of metal ions from solution. Preliminary results indicate that graphite nanofibers can, in the presence or absence of an applied electric field, capture metal ions from solution. In addition, it has been found that certain types of nanofibers can absorb substantial amounts of water both in the vapor and liquid phase.

2000-01-01

199

Removal of Heavy Metals and Organic Contaminants from Aqueous Streams by Novel Filtration Methods  

Energy Technology Data Exchange (ETDEWEB)

The removal of hazardous waste, generated by the dismantling of nuclear weapons is a problem that requires urgent attention by the US Department of Energy. Low levels of radioactive contaminants combined with organic solvent residues have leaked from aging containers into the soil and underground water in the surrounding area. Due to the complexity of the problem, it is evident that traditional adsorption methods are ineffective, since the adsorbent tends to saturate with the aqueous component. It has become apparent that a much more aggressive approach is required which involves the use of specially designed materials. We have investigated the potential of solids that combine high surface area/high pore volume and high electrical conductivity, a rare combination of properties found in a single material. In this program we examined the potential of newly developed materials for the trapping of organic solvents within specially engineered cavities without allowing the material to become saturated with water. Catalytically grown carbon nanofibers are a set of novel structures that are produced by the decomposition of selected carbon-containing gases over metal particles. These materials consist of extremely small graphite platelets stacked in various orientations with respect to the fiber axis. Such an arrangement results in a unique structure that is composed of an infinite number of extremely short and narrow pores, suitable for sequestering small molecules. In addition, when the graphene layers are aligned parallel to the fiber axis, an unusual combination of high surface area and low electrical resistivity solids are attained. We have attempted to capitalize on this blend of properties by using such structures for the selective removal of organic contaminants from aqueous streams. Experimental results indicate that nanofibers possessing a structure in which the graphite platelets are aligned perpendicular to the fiber axis and possessing a high degree of structural perfection exhibit superior selective adsorption properties with respect to removal of alcohols from aqueous medial over that displayed by active carbon. Furthermore, we have attempted to take advantage of the high electrical conductivity as well as the high availability of edges, and we have used these materials for the removal of metal ions from solution. Preliminary results indicate that graphite nanofibers can, in the presence or absence of an applied electric field, capture metal ions from solution. In addition, it has been found that certain types of nanofibers can absorb substantial amounts of water both in the vapor and liquid phase.

Rodriguez, N.M.

2000-08-01

200

Removal of heavy metals from wastewater using CFB-coal fly ash zeolitic materials  

International Nuclear Information System (INIS)

[en] Polish bituminous (PB) and South African (SA) coal fly ash (FA) samples, derived from pilot-scale circulated fluidized bed (CFB) combustion facilities, were utilized as raw materials for the synthesis of zeolitic products. The two FAs underwent a hydrothermal activation with 1 M NaOH solution. Two different FA/NaOH solution/ratios (50, 100 g/L) were applied for each sample and several zeolitic materials were formed. The experimental products were characterized by means of X-ray diffraction (XRD) and energy dispersive X-ray coupled-scanning electron microscope (EDX/SEM), while X-ray fluorescence (XRF) was applied for the determination of their chemical composition. The zeolitic products were also evaluated in terms of their cation exchange capacity (CEC), specific surface area (SSA), specific gravity (SG), particle size distribution (PSD), pH and the range of their micro- and macroporosity. Afterwards the hybrid materials were tested for their ability of adsorbing Cr, Pb, Ni, Cu, Cd and Zn from contaminated liquids. Main parameters for the precipitation of the heavy metals, as it was concluded from the experimental results, are the mineralogical composition of the initial fly ashes, as well as the type and the amount of the produced zeolite and specifically the mechanism by which the metals ions are hold on the substrate.

2010-01-15

 
 
 
 
201

Biological removal of heavy metals by sulfate reduction using a submerged packed tower  

Energy Technology Data Exchange (ETDEWEB)

The Coors Brewing Co. owns and operates two wastewater treatment plants which handle the combined waste of the City of Golden and the Brewery. The discharge permit for Coors contains very strict limits for metals. Silver and mercury are prohibited from discharge at all and copper and zinc are both at low limits. The copper and zinc limits cannot be achieved with the present plant configuration and several programs are underway to reduce the source concentrations to meet the respective limits. Most of the programs are either very expensive or unlikely to produce the needed results soon enough. One possible treatment alternative that has been described in literature is sulfate reduction leading to the generation of hydrogen sulfide. The hydrogen sulfide in turn can precipitate most divalent metals that are available, though there are limits on the precipitation process. The purpose of this research has been to investigate the use of sulfate reduction to remove metals from the effluent of the Coors` Process Waste Treatment Plant (PWTP).

Neserke, G. [Coors Brewing Co., Golden, CO (United States); Figueroa, L.; Cook, N. [Colorado School of Mines, Golden, CO (United States). Environmental Science and Engineering Division

1994-12-31

202

Removal of heavy metals from fly ash and the impact on its quality  

Energy Technology Data Exchange (ETDEWEB)

Most coal fly ashes currently produced in The Netherlands contain leachable trace elements in amounts higher than allowed by Dutch law for its free application as a granular building material. To improve their technical and environmental quality, these ashes were subjected to forced leaching using water, citrate, oxalate, EDTA and carbonate solutions. With water alone, the free lime and substantial amounts of Mo (30%), Se (20-40%) and SO{sub 4}{sup 2}- (40-50%) are removed. Using the extraction agents, these percentages increase to 60-90% and in addition 15-20% Cr, V and Sb are removed. Most of the extraction agents used form stable complexes or compounds with Ca{sup 2+}; thus prewashing with water followed by treatment with extraction agents resulted in higher removal and/or lower reagent consumption. The environmental quality of the washed fly ash was evaluated using the Dutch standard leaching test (NEN7343). Leachability of oxyanions decreased by a factor of 2-4 after washing with water and by between 2 and I8 after washing with extraction agents. However, combined washing did not further decrease leaching but in some cases caused increased leaching. Selection of the washing procedure thus depends on the subsequent application of the ash, that is whether low concentrations or low mobility of trace elements are required. Removing extractants and metals remaining in the moisture after filtration will further decrease leaching. For a feasible process reduction of reagent consumption and simple methods for process water recycling are needed.

Nugteren, H.W.; Janssen-Jurkovicova, M.; Scarlett, B. [Delft University of Technology, Delft (Netherlands). Particle Technology Group

2002-07-01

203

Heavy metal removal from produced water using retorted shale; Remocao de metais pesados em aguas produzidas utilizando xisto retortado  

Energy Technology Data Exchange (ETDEWEB)

The Production of oil and gas is usually accompanied by the production of large volume of water that can have significant environmental effects if not properly treated. In this work, the use of retort shale was investigated as adsorbent agent to remove heavy metals in produced water. Batch adsorption studies in synthetic solution were performed for several metal ions. The efficiency removal was controlled by solution pH, adsorbent dosage, and initial ion concentration and agitation times. Two simple kinetic models were used, pseudo-first- and second-order, were tested to investigate the adsorption mechanisms. The equilibrium data fitted well with Langmuir and Freundlich models. The produced water samples were treated by retorted shale under optimum adsorption conditions. Synchrotron radiation total reflection X-ray fluorescence was used to analyze the elements present in produced water samples from oil field in Rio Grande do Norte, Brazil. The removal was found to be approximately 20-50% for Co, Ni, Sr and above 80% for Cr, Ba, Hg and Pb. (author)

Pimentel, Patricia M.; Melo, Marcos A.F.; Melo, Dulce M.A.; Silva Junior, Carlos N.; Assuncao, Ary L.C. [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil); Anjos, Marcelino J. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia

2004-07-01

204

Application of the artificial intelligence to estimate the constructed wetland response to heavy metal removal  

International Nuclear Information System (INIS)

Current design approaches lack essential parameters necessary to evaluate the removal of metals contained in wastewater which is discharged to constructed wetlands. As a result, there is no guideline for an accurate design of constructed wetlands. An artificial intelligence approach was used to assess constructed wetland design. For this purpose concentrations of bioavailable mercury were evaluated in conditions where initial concentrations of inorganic mercury, chloride concentrations and pH values changed. Fuzzy knowledge base was built based on results obtained from previous investigations performed in a greenhouse for floating plants, and from computations for mercury speciation. The Fuzzy Decision Support System (FDSS) used the knowledge base to find parameters that permit to generate the highest amount of mercury available for plants. The findings of this research can be applied to wetlands and all natural processes where correlations between them are uncertain. (author)

2002-01-01

205

Fe3O4/cyclodextrin polymer nanocomposites for selective heavy metals removal from industrial wastewater.  

UK PubMed Central (United Kingdom)

In this work, carboxymethyl-?-cyclodextrin (CM-?-CD) polymer modified Fe(3)O(4) nanoparticles (CDpoly-MNPs) was synthesized for selective removal of Pb(2+), Cd(2+), Ni(2+) ions from water. This magnetic adsorbent was characterized by TEM, FTIR, XPS and VSM. The adsorption of all studied metal ions onto CDpoly-MNPs was found to be dependent on pH, ionic strength, and temperature. Batch adsorption equilibrium was reached in 45 min and maximum uptakes for Pb(2+), Cd(2+) and Ni(2+) in non-competitive adsorption mode were 64.5, 27.7 and 13.2 mg g(-1), respectively at 25 °C. Adsorption data were fitted well to Langmuir isotherm and pseudo-second-order models for kinetic study. The polymer grafted on MNPs enhanced the adsorption capacity because of the complexing abilities of the multiple hydroxyl and carboxyl groups in polymer backbone with metal ions. In competitive adsorption experiments, CDpoly-MNPs could preferentially adsorb Pb(2+) ions with an affinity order of Pb(2+)>>Cd(2+)>Ni(2+) which can be explained by hard and soft acids and bases (HASB) theory. Furthermore, we explored the recyclability of CDpoly-MNPs.

Badruddoza AZ; Shawon ZB; Tay WJ; Hidajat K; Uddin MS

2013-01-01

206

Synthesis of pellet-type red mud adsorbents for removal of heavy metal ions  

Energy Technology Data Exchange (ETDEWEB)

Red mud is generated as a by-product in the production of Al(OH){sub 3}/Al{sub 2}O{sub 3} from bauxite ore. In this study the pellet-type adsorbents have been made from the red mud, and their adsorption capacities of heavy metal ions have been tested. The pellet-type adsorbents were synthesized to utilize the excellent adsorption capacity of the powder-type adsorbent for industrial application. The pellet-type adsorbents were prepared by mixing several kinds of additives with the red mud. It is found that the pellet-type adsorbent, made by sintering a mixture of red mud (96.0 wt%), polypropylene (2.5 wt%), fly ash (0.5 wt%), and sodium meta-silicate (1.0 wt%) at 1200 deg.C for 30 minutes, has the highest adsorption capacity. In this work, the two kinds of pellet-type adsorbents (bead-type, crushed-type) were prepared. The crushed-type adsorbent was found to show a better adsorption/desorption performance than the bead-type adsorbent. The crushed-type adsorbent showed a good adsorption capacity of Pb{sup 2+} like the powder-type adsorbent. (author). 13 refs., 5 tabs., 13 figs.

Kim, Jung-Sik; Han, Sang-Won; Hwang, In-Gook; Bae, Jae-Heum; Choi, Woo-Zin [The University of Suwon, Whasung(Korea)

2000-02-28

207

Biosorption of heavy metals  

Energy Technology Data Exchange (ETDEWEB)

Only within the past decade has the potential of metal biosorption by biomass materials been well established. For economic reasons, of particular interest are abundant biomass types generated as a waste byproduct of large-scale industrial fermentations or certain metal-binding algae found in large quantities in the sea. These biomass types serve as a basis for newly developed metal biosorption processes foreseen particularly as a very competitive means for the detoxification of metal-bearing industrial effluents. The assessment of the metal-building capacity of some new biosorbents is discussed. Lead and cadmium, for instance, have been effectively removed from very dilute solutions by the dried biomass of some ubiquitous species of brown marine algae such as Ascophyllum and Sargassum, which accumulate more than 30% of biomass dry weight in the metal. Mycelia of the industrial steroid-transforming fungi Rhizopus and Absidia are excellent biosorbents for lead, cadmium, copper, zinc, and uranium and also bind other heavy metals up to 25% of the biomass dry weight. Biosorption isotherm curves, derived from equilibrium batch sorption experiments, are used in the evaluation of metal uptake by different biosorbents. Further studies are focusing on the assessment of biosorbent performance in dynamic continuous-flow sorption systems. In the course of this work, new methodologies are being developed that are aimed at mathematical modeling of biosorption systems and their effective optimization. 115 refs., 7 figs., 3 tabs.

Volesky, B. [McGill Univ., Montreal (Canada)]|[B.V. Sorbex, Inc., Montreal (Canada); Holan, Z.R. [McGill Univ., Montreal (Canada)

1995-05-01

208

Impact of carbonate on the efficiency of heavy metal removal from kaolinite soil by the electrokinetic soil remediation method  

International Nuclear Information System (INIS)

While the feasibility of using electrokinetics to decontaminate soils has been studied by several authors, the effects of soil composition on the efficiency of this method of decontamination has yet to be fully studied. This study focuses its attention on the effect of 'calcite or carbonate' (CaCO3) on removal efficiency in electrokinetic soil remediation. Bench scale experiments were conducted on two soils: kaolinite and natural-soil of a landfill in Hamedan, Iran. Prescribed quantities of carbonates were mixed with these soils which were subsequently contaminated with zinc nitrate. After that, electrokinetic experiments were conducted to determine the efficiency of electrokinetic remediation. The results showed that an increase in the quantity of carbonate caused a noticeable increase on the contaminant retention of soil and on the resistance of soil to the contaminant removal by electrokinetic method. Because the presence of carbonates in the soil increases its buffering capacity, acidification is reduced, resulting in a decrease in the rate of heavy metal removed from the contaminant soil. This conclusion was validated by the evaluation of efficiency of electrokinetic method on a soil sample from the liner of a waste disposal site, with 28% carbonates.

2010-01-15

209

Removal of heavy metals, Cd(II) and Pb(II) ions in water by sargassum herneri  

Energy Technology Data Exchange (ETDEWEB)

Brown algae, Sargassum horneri, was used as an adsorbent to remove heavy metal Cd(II) and Pb(II) ions. Sargassum horneri picked in East Coast was formulated into the grain with the size of 40-60 mesh after wind dry. Batch method was used in order to investigate the adsorption rate by measuring the adsorption amounts with shaking time. In the column method, the adsorption amounts were measured by flowing metal solutions into the algae-packed column method, the adsorption amounts were measured by flowing metal solutions into the algae-packed column at the rate of 1 ml/min. Adsorption amounts in both batch method and column method were in the following order ; pH 10.5>7.0>3.5. It was found that Pb(II) was more adsorbed on the algae grain than Cd(II). It was also revealed that the adsorption amounts reached the maximum within 5 minutes irrespective of pH condition in the batch method. It was concluded that the batch method was more effective than the column method in terms of recovery rate. 17 refs., 6 figs., 2 tabs.

Park, K.W.; Park, M.A.; Jang, H.; Kim, Y.H. [Kangnung University, Kangnung (Korea); Kim, E.K. [Se Myung University, Jecheon (Korea)

1999-06-01

210

Biosorption of heavy metals.  

UK PubMed Central (United Kingdom)

Only within the past decade has the potential of metal biosorption by biomass materials been well established. For economic reasons, of particular interest are abundant biomass types generated as a waste byproduct of large-scale industrial fermentations or certain metal-binding algae found in large quantities in the sea. These biomass types serve as a basis for newly developed metal biosorption processes foreseen particularly as a very competitive means for the detoxification of metal-bearing industrial effluents. The assessment of the metal-binding capacity of some new biosorbents is discussed. Lead and cadmium, for instance, have been effectively removed from very dilute solutions by the dried biomass of some ubiquitous species of brown marine algae such as Ascophyllum and Sargassum, which accumulate more than 30% of biomass dry weight in the metal. Mycelia of the industrial steroid-transforming fungi Rhizopus and Absidia are excellent biosorbents for lead, cadmium, copper, zinc, and uranium and also bind other heavy metals up to 25% of the biomass dry weight. Biosorption isotherm curves, derived from equilibrium batch sorption experiments, are used in the evaluation of metal uptake by different biosorbents. Further studies are focusing on the assessment of biosorbent performance in dynamic continuous-flow sorption systems. In the course of this work, new methodologies are being developed that are aimed at mathematical modeling of biosorption systems and their effective optimization. Elucidation of mechanisms active in metal biosorption is essential for successful exploitation of the phenomenon and for regeneration of biosorbent materials in multiple reuse cycles. The complex nature of biosorbent materials makes this task particularly challenging. Discussion focuses on the composition of marine algae polysaccharide structures, which seem instrumental in metal uptake and binding. The state of the art in the field of biosorption is reviewed in this article, with many references to recent reviews and key individual contributions.

Volesky B; Holan ZR

1995-05-01

211

Application of polyuronides for removing heavy metals from vegetable oils. III. Application of alginic acid, pectic and pectinic acids for demetalization of hydrogenated sunflower oil.  

UK PubMed Central (United Kingdom)

Laboratory experiments have been carried out for the removal of heavy metals from hydrogenated vegetable oils using hydrated polyuronides (degree of swelling from 4 to 12.8 ml/g) such as alginic acid, pectic and pectinic acids. The effect of the type of polyuronide, degree of esterification and oil treatment on the degree of demetalization has been studied. It has been shown that with increase in the degree of esterification of the polyuronide the efficiency of demetalization decreases. The second and third treatment of the hydrogenated oil with pectinic acid resulted in a high degree of heavy metal removal. The possibility of efficient demetalization of hydrogenated oils by treatment with water solutions of pectinic acids has also been demonstrated. The degree of metal ion removal increases with decreasing concentration of pectinic acids in the water solution.

Ivanov K; Popova M; Denev P; Kratchanov C

1992-11-01

212

Application of polyuronides for removing heavy metals from vegetable oils. III. Application of alginic acid, pectic and pectinic acids for demetalization of hydrogenated sunflower oil.  

Science.gov (United States)

Laboratory experiments have been carried out for the removal of heavy metals from hydrogenated vegetable oils using hydrated polyuronides (degree of swelling from 4 to 12.8 ml/g) such as alginic acid, pectic and pectinic acids. The effect of the type of polyuronide, degree of esterification and oil treatment on the degree of demetalization has been studied. It has been shown that with increase in the degree of esterification of the polyuronide the efficiency of demetalization decreases. The second and third treatment of the hydrogenated oil with pectinic acid resulted in a high degree of heavy metal removal. The possibility of efficient demetalization of hydrogenated oils by treatment with water solutions of pectinic acids has also been demonstrated. The degree of metal ion removal increases with decreasing concentration of pectinic acids in the water solution. PMID:1462709

Ivanov, K; Popova, M; Denev, P; Kratchanov, C

1992-11-01

213

A study on removal of heavy metals and pH increasing effects in plating wastewater using oyster shells  

Energy Technology Data Exchange (ETDEWEB)

In the present, batch test was conducted to evaluate the neutralization and adsorption of heavy metals from the plating wastewater using oyster shells. The smaller particle size of oyster shells, the higher neutralization and adsorption efficiencies of heavy metals with increasing time. It seemed that adsorption efficiencies of heavy metals were influenced by competitive reaction within a same pH range rather than solubility. As a result on the experiments of Freundlich isotherm, the adsorption capacities(k) were Fe 3.66 and Cr 1.24, respectively and the adsorption intensities(1/n) were Fe 3.3 and Cr 2.55, respectively. In view of these results, it showed that ocean wastes containing the similar compositions as oyster shells could utilize the neutralization and adsorption of heavy metals in plating wastewater. (author). 14 refs., 1 tab., 7 figs.

Kim, Eun Ho; Kim, Jung Kwon; Sung, Nak Chang [Dong-A University, Pusan (Korea, Republic of)

1997-08-31

214

OPTIMIZATION OF MOTOR VEHICLE INDUSTRIES WASTEWATER TREATMENT METHODS WITH THE AIM OF HEAVY METALS REMOVAL AND WATER REUSE IN PILOT SCALE  

Directory of Open Access Journals (Sweden)

Full Text Available The waste of motor vehicle industries is mainly the result of washing, coloring and various stages of chassis manufacturing, which include oil, grease, dyestuff, chromium, phosphate and other pollutants. In the present research, extended aeration activated sludge biological treatment plant is being considered and evaluated, for the removal of heavy metals and pollution load from industrial wastes and sanitary wastewaters, and on the pilot scale for optimization of waste treatment method for motor vehicle industries. To accomplish the pilot experiments, the natural waste of Bahman motor vehicle factory is used. Effective factors on efficient removal of heavy metals and pollution load such as concentration of biological mass (MLVSS), COD, BOD, pH in the extended aeration activated sludge biological treatment system, in different ratios of the mixing of industrial waste to sanitary wastewater have been experimented and evaluated. The performance of the above system, in the best of conditions, removes about 90% of pollution load and 65% of heavy metals existing in the industrial wastes. After analyzing the experiments, it is concluded that the removal of heavy metals through biological methods is possible and moreover it is feasible to biologically treat the mixing of motor vehicle industries effluent and sanitary wastewater up to the ratio of one to one, if guided exactly and scientifically.

S. A. Mirbagheri, M. Salehi M

2006-01-01

215

Removal of heavy metals by exopolymeric substances produced by resistant purple nonsulfur bacteria isolated from contaminated shrimp ponds  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english Two purple nonsulfur bacteria (PNSB) strains, Rhodobium marinum NW16 and Rhodobacter sphaeroides KMS24 were investigated for their potential to remove heavy metals (HMs) from contaminated shrimp pond water. Tolerance of both PNSB strains growing with both microaerobic-light and aerobic-dark conditions, based on their minimum inhibitory concentrations, was in the order of Cu2+ > Zn2+ > Cd2+ (Pb precipitation occurred at 0.34 mM). Results from a scanning electron microscope (more) equipped with an energy dispersive X-ray spectrometer (SEM-EDX) indicated that Cu2+ and Zn2+ altered the cellular morphology of both strains and accumulated HMs were found in their cells. The highest amounts of both cations were found in their cell walls followed by the cytoplasm and cell membrane. Using the highest concentrations (mM) of HMs found in shrimp pond of 0.0067 Cd2+, 0.54 Cu2+, 0.30 Pb2+, 0.89 Zn2+ and 3% NaCl under both incubating conditions exopolymeric substances (EPS) produced by both strains showed a greater removal of all HMs (average percentages; 90.52-97.29) than their cells (average percentages; 14.02-75.03).

Panwichian, Saijai; Kantachote, Duangporn; Wittayaweerasak, Banjong; Mallavarapu, Megharaj

2011-07-01

216

Electrodialytic remediation of harbour sediment in suspension - Evaluation of effects induced by changes in stirring velocity and current density on heavy metal removal and pH  

DEFF Research Database (Denmark)

Electrodialytic remediation was used to remove heavy metals from a suspension of dredged harbour sediment. The studied metals Cu, Pb, Zn and Cd are normally strongly bound in anoxic sediment. Six electrodialytic laboratory remediation experiments were made, lasting 14 days and under oxic conditions. The influence on the metal removal was investigated by changing current densities and stirring velocity of the sediment suspension. Using a current density of 1.0 mA/cm2 gave the highest metal removal. The sediment suspension was partly oxidised when mixed into a suspension for the electrodialytic remediation experiments and was further oxidised during the experiments. Even at low stirring velocities, oxic conditions were obtained. The metal removal was dependent on the achieved pH in the sediment and the highest metal removal and corresponding low pH was obtained by using a current density of 1.0 mA/cm2 and a stirring velocity of the sediment suspension of 1000 rpm. The highest removal obtained was 98% Cd, 78% Zn, 65% Pb and 44% Cu after 14 days of remediation. The metal removal was more dependent on the stirring velocity than on the current density. When manually stirring the sediment suspension or using a stirring velocity of 60 rpm the sediment deposited, which led to a slightly higher pH in the sediment and keeping all the sediment in suspension is essential for a successful remediation.

Kirkelund, Gunvor Marie; Ottosen, Lisbeth M.

2009-01-01

217

Heavy-metal removal from aqueous solution by fungus Mucor rouxii.  

UK PubMed Central (United Kingdom)

Biosorption of lead, cadmium, nickel and zinc by live and dead Mucor rouxii biomass treated with NaOH was studied over a range of pH. In the case of dead biomass, low pH resulted in a decrease in the biosorption capacity. At pH 3.0 or less, the inhibition of biosorption of metal ions took place. At pH 4.0 or higher, the biosorption of metal ions increased sharply. Ho's pseudo-second-order model described the biosorption kinetics better than the Lagergren model. Live biomass had high biosorption capacity, i.e. 35.69, 11.09, 8.46 and 7.75 mg/g at pH 5.0 for Pb(2+), Ni(2+), Cd(2+) and Zn(2+), respectively. The dead biomass adsorbed metal ions in the order of Pb(2+), Zn(2+), Cd(2+) and Ni(2+), with the biosorption capability of 25.22, 16.62, 8.36 and 6.34 mg/g at pH 5.0, respectively. At pH 6.0, the capacity of the dead biomass increased to 53.75, 53.85, 20.31 and 20.49 mg/g, respectively. For bi- or multi-metal ion adsorption, biosorption capacity of individual metal ion was reduced in the presence of other metal ions, but the total biosorption capacity increased, indicating the capability of M. rouxii biomass in adsorbing multi-metal ions. In addition, M. rouxii biomasses cultured with different media exhibited the same level of capacity to bind metal ions. Metal ions adsorbed by the biomass could be eluted effectively with HNO(3), while distilled water demonstrated negligible metal elution capability. Regeneration of the biomass with NaOH regained or enhanced the biosorption capacity even after five cycles of adsorption-elution-regeneration.

Yan G; Viraraghavan T

2003-11-01

218

Effects of moisture content and initial pH in composting process on heavy metal removal characteristics of grass clipping compost used for stormwater filtration.  

UK PubMed Central (United Kingdom)

Heavy metals are common contaminants in stormwater runoff. One of the devices that can be used to effectively and economically remove heavy metals from runoff is a yard waste compost stormwater filter. The primary goal of composting is to reduce waste volume rather than to produce stormwater filter media. Moisture content (MC) and initial pH, the two important parameters in composting, were studied for their effects on yard waste volume reduction and heavy metal adsorption performances of the compost. The main objective of this investigation was to examine whether the conditions that provided high yard waste volume reduction would also result in compost with good heavy metal removal performances. Manila grass was composted at different initial pHs (5-9) and MCs (30-70%) and the composts were used to adsorb cadmium, copper, lead and zinc from water. Results indicated that MC is more critical than initial pH for both volume reduction and production of compost with high metal adsorption performances. The most optimal conditions for the two attributes were not exactly the same but lower MCs of 30-40% and pH 7 or higher tended to satisfy both high volume reduction and effective metal adsorption.

Khan E; Khaodhir S; Ruangrote D

2009-10-01

219

Sorbents for the removal of airborne heavy metals from incinerator effluent  

Energy Technology Data Exchange (ETDEWEB)

The effectiveness of inorganic alumino-silicate sorbents (alumina and kaolinite) to adsorb airborne lead and cadmium from the effluent stream of a simulated waste incinerator was studied. A 20 kW (68,000 BTU/h) flow reactor was used to achieve the temperature and residence times typical of a waste incinerator. Solutions containing lead or cadmium were introduced yielding airborne metals concentrations between 15 and 150 ppm. Gas samples were drawn into a particle impactor that collected the airborne particles and condensed phase metal aerosols, separating them into ten size ranges from 0.2 {mu}m to greater than 10{mu}m. Metals to sorbent mass ratios between 0.03 and 1.56 were investigated. Scavenging efficiency increased as the ratio of sorbent to injected metal mass was increased. The scavenging efficiencies were as high as 76% for lead scavenged by kaolinite to as low as 14% for cadmium scavenged by alumina.

Chun, P.; Hall, M.J. [Univ. of Texas, Austin, TX (United States). Center for Energy Studies

1994-12-31

220

Sorptive removal of technetium from heavy metals sludge filtrate containing nitrate ion  

International Nuclear Information System (INIS)

[en] We have found that cross-linked polyvinylpyridine (PVP) resin is more efficient than strongly basic anion-exchange resin for removal of technetium in wastes containing high concentrations of nitrate ion. Resin loading by nitrate is greatly reduced, and PVP resins are very stable with respect to chemical and radiological degradation. We have also found that the inexpensive inorganic reagents, elemental iron and ferrous sulfide, are very efficient for the removal of technetium and soluble mercury from aqueous nitrate wastes. The spent reactant and sorbent occupies a much smaller volume (per unit of technetium removed) than does organic resin, and the spent reactant can be immobilized into grout, with a very low leach rate for technetium. 30 refs., 5 figs., 13 tabs

1988-01-01

 
 
 
 
221

Removal of metal ions from aqueous solution  

Energy Technology Data Exchange (ETDEWEB)

A method is disclosed of removing heavy metals from aqueous solution, a composition of matter used in effecting said removal, and apparatus used in effecting said removal. One or more of the polypeptides, poly ([gamma]glutamylcysteinyl)glycines, is immobilized on an inert material in particulate form. Upon contact with an aqueous solution containing heavy metals, the polypeptides sequester the metals, removing them from the solution. There is selectivity of poly ([gamma]glutamylcysteinyl)glycines having a particular number of monomer repeat unit for particular metals. The polypeptides are easily regenerated by contact with a small amount of an organic acid, so that they can be used again to remove heavy metals from solution. This also results in the removal of the metals from the column in a concentrated form. 1 fig.

Jackson, P.J.; Delhaize, E.; Robinson, N.J.; Unkefer, C.J.; Furlong, C.

1990-11-13

222

Removal of metal ions from aqueous solution  

Energy Technology Data Exchange (ETDEWEB)

A method of removing heavy metals from aqueous solution, a composition of matter used in effecting said removal, and apparatus used in effecting said removal. One or more of the polypeptides, poly (.gamma.-glutamylcysteinyl)glycines, is immobilized on an inert material in particulate form. Upon contact with an aqueous solution containing heavy metals, the polypeptides sequester the metals, removing them from the solution. There is selectivity of poly (.gamma.-glutamylcysteinyl)glycines having a particular number of monomer repeat units for particular metals. The polypeptides are easily regenerated by contact with a small amount of an organic acid, so that they can be used again to remove heavy metals from solution. This also results in the removal of the metals from the column in a concentrated form.

Jackson, Paul J. (Los Alamos, NM); Delhaize, Emmanuel (Los Alamos, NM); Robinson, Nigel J. (Durham, GB2); Unkefer, Clifford J. (Los Alamos, NM); Furlong, Clement (Seattle, WA)

1990-01-01

223

Removal of metal ions from aqueous solution  

Energy Technology Data Exchange (ETDEWEB)

This patent describes a method of removing heavy metals from aqueous solution, a composition of matter used in effecting the removal, and apparatus used in effecting the removal. One or more of the polypeptides, poly ({gamma}-glutamylcysteinyl)glycines, is immobilized on an inert material in particulate form. Upon contact with an aqueous solution containing heavy metals, the polypeptides sequester the metals, removing them from the solution. There is selectivity of poly ({gamma}-glutamylcysteinyl)glycines having a particular number of monomer repeat units for particular metals. The polypeptides are easily regenerated by contact with a small amount of an organic acid, so that they can be used again to remove heavy metals from solution. This also results in the removal of the metals from the column in a concentrated form.

Jackson, P.J.; Delhaize, E.; Robinson, N.J.; Unkefer, C.J.; Furlong, C.

1990-03-20

224

Removal of metal ions from aqueous solution  

Energy Technology Data Exchange (ETDEWEB)

A method of removing heavy metals from aqueous solution, a composition of matter used in effecting said removal, and apparatus used in effecting said removal. One or more of the polypeptides, poly ({gamma}-glutamylcysteinyl)glycines, is immobilized on an inert material in particulate form. Upon contact with an aqueous solution containing heavy metals, the polypeptides sequester the metals, removing them from the solution. There is selectivity of poly ({gamma}-glutamylcysteinyl)glycines having a particular number of monomer repeat units for particular metals. The polypeptides are easily regenerated by contact with a small amount of an organic acid, so that they can be used again to remove heavy metals from solution. This also results in the removal of the metals from the column in a concentrated form.

Jackson, P.J.; Delhaize, E.; Robinson, N.J.; Unkefer, C.J.; Furlong, C.

1988-08-26

225

Fabrication of chelating diethylenetriaminated pan micro and nano fibers for heavy metal removal  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this study, commercial acrylic fibers were modified with diethylenetriamine to prepare metal chelating fibers. The effects of process parameters on the efficiency of the reaction were investigated. FTIR spectroscopy and TGA analysis were used to confirm the chemical changes made to the fibers...

Abdouss Majid; Shoushtari Mousavi Ahmad; Haji Aminoddin; Moshref Behnam

226

Polyaza macroligands as potential agents for heavy metal removal from wastewater  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Two polyaza macroligands N,N´-bis(2-aminobenzyl)-1,2- ethanediamine (L1) and 3,6,9,12-tetraaza-4(1,2),11(1,2)-dibenzo-1(1,3)- piridinaciclotridecafano (L2) were characterized and investigated for their metal ion extraction capabilities. The nature of all complexes was established by spectroscopic...

Elizondo Martínez Perla; Nájera Martínez Blanca; Pérez Rodríguez Nancy; Reyes Hinojosa Laura; Río Del Gómez Isabel Ma

227

Removal of selected heavy metals from MSW fly ash by the electrodialytic process  

DEFF Research Database (Denmark)

This paper aims to assess the applicability of the electrodialytic remediation technique for the removal of zinc, lead, copper and cadmium from municipal solid waste (MSW) incinerator fly ash. A broad range of experimental conditions were studied including current densities, remediation times, use of assisting agents and cell design. Several operational problems were identified during the electrodialytic experiments, among which are formation of precipitates, dryness of sample and partial dissolution of sample creating preferential pathways for the electric current. These problems may explain the low remediation efficiencies obtained. Comparison between experiments showed that generally the use of Na-gluconate as assisting agent leads to better results than distilled water. Increasing the concentration of the assisting agent also results in higher removals.

Ferreira, Célia Maria Dias; Jensen, Pernille Erland

2005-01-01

228

Removal of Heavy Metals from Aqueous Systems with Thiol Functionalized Superparamagnetic Nanoparticles  

Energy Technology Data Exchange (ETDEWEB)

We have shown that superparamagnetic iron oxide (Fe3O4) nanoparticles with a surface functionalization of dimercaptosuccinic acid is an effective, magnetic, sorbent material for toxic metals such as Hg, Ag, Pb, Cd and other soft cations. The chemical affinity, stability, capacity and kinetics of the functionalized nanoparticles has been explored and compared to conventional resin based sorbents and nanoporous silica materials with similar surface chemistries.

Yantasee, Wassana; Warner, Cynthia L.; Sangvanich, Thanapon; Addleman, Raymond S.; Carter, Timothy G.; Wiacek, Robert J.; Fryxell, Glen E.; Timchalk, Chuck; Warner, Marvin G.

2007-06-09

229

Estimation and removal of selected heavy metal ions from tanneries liquid waste and sediments  

International Nuclear Information System (INIS)

Concentration of potentially toxic and general metals Cu, Co, Cr, Cd, Mn, Zn, Ni and Pb in sediments and liquid waste samples of selected tanneries ware measured by atomic absorption spectrophotometer, after digestion with nitric acid. The corresponding analytical data revealed elevated concentrations of above mentioned metals compared to the permissible levels including chromium which steels into the sediments. Selective separation of chromium in sediment from other metal ions has been investigated using activated charcoal and employing batch technique. The effects of adsorbent concentration, pH, shaking time and percentage reduction in chromium concentration (93 - 99 %) with temperature have been studied. The adsorption equilibrium data were fitted in Freundlich, Dubinin, Redushkevich and Virial isotherms equations at temperatures 303K to 318K. Thermodynamic parameters delta H-zero degree, delta S- zero degree and delta G zero degree were calculated using Virial isotherm expression. The values of free energy of adsorption delta G decrease with increase in temperature and show endothermic nature of adsorption of Chromium on activated charcoal. (authors)

1997-01-01

230

Isolation of purple nonsulfur bacteria for the removal of heavy metals and sodium from contaminated shrimp ponds  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english In order to determine whether waters used for the shrimp cultivation contained toxic levels of heavy metals (HMs) and sodium (Na), analysis was carried out on 31 shrimp ponds in areas of southern Thailand. Purple nonsulfur bacteria (PNB) were also isolated from the same ponds to investigate if they could be used for bioremediation of the above contaminants. The highest HMs concentrations of the sediment samples in mg/kg dry weight were found as follows: 0.75 cadmium (Cd), (more) 62.63 lead (Pb), 34.60 copper (Cu) and 58.50 zinc (Zn). However, all sediment samples met Hong Kong standards for dredged sediment. In contrast, contamination of Cu (9-30 µg/L) and Zn (140-530 µg/L) exceeding the standard guidelines for marine aquatic animal set by the Pollution Control Department, Thailand, were found in 32 and 61% of water samples, respectively. Two metal resistant PNB isolates, NW16 and KMS24, were selected from the 120 PNB isolates obtained. Both isolates reduced the levels of HMs by up to 39% for Pb, 20% for Cu, 7% for Cd, 5% for Zn and 31% for Na from water that contained the highest levels of HMs found and 3% NaCl when cultured with either microaerobic-light or aerobic-dark conditions. The isolate NW16 removed a greater percentage of the HMs than the isolate KMS24, but the isolate KMS24 was able to survive better under a greater variety of environmental conditions. Both strains were therefore suitable to use for further investigating their abilities to remediate water contaminated with HMs and Na.

Panwichian, Saijai; Kantachote, Duangporn; Wittayaweerasak, Banjong; Mallavarapu, Megharaj

2010-07-01

231

Heavy metals and coal combustion  

Energy Technology Data Exchange (ETDEWEB)

Combustion of coal may be an important source of heavy metals pollution. The distribution of heavy metals during combustion process has been studied in six power plants, where fuel, bottom ash, fly ash and emissions have been analyzed and the relative concentrations of heavy metals have been estimated. For the most volatile metals (arsenic, antimony, lead, and zinc), the redistribution process involving condensation on surface is probable. Some metals like manganese or chromium are concentrated rather in coarse particles. In such cases, no clear conclusion can be made and probably several mechanisms are involved, including mineral form of metal. Typical results of low chlorine coal (0.01--0.03% Cl) exhibit increasing concentration of volatile metals in the magnitude of around one order when going from bottom ash to emissions. Different results have been found in similar operation conditions in the case of high content of chlorine in coal (0.3% of Cl in coal). In this case, the concentration of metals in emissions is significantly higher and also nickel, copper and manganese concentrations increase. It seems to be probable that chlorine in the coal increases the redistribution of metals by volatile chlorides formation. At three operation condition (nominal output, 70% and 40% respectively) emission factors of heavy metals have been estimated for 35 MW stoker-fired boiler. Ba, Pb, Sb and Zn increased their emission factors and Cr and Mn decreased when output was decreased. Heavy metals pollution caused by emissions from combustion of coal may be decreased by fine particles removal, other possibilities (metals extraction from the coal, changes of condition in the flame) are rather limited.

Danihelka, P.; Ochodek, T.; Noskievic, P.; Seidlerova, J.

1998-07-01

232

Removal of metal ions from aqueous solution  

Energy Technology Data Exchange (ETDEWEB)

A method of removing heavy metals from aqueous solution, a composition of matter used in effecting said removal, and apparatus used in effecting said removal. One or more of the polypeptides, poly (.gamma.-glutamylcysteinyl)glycines, is immobilized on an inert material in particulate form. Upon contact with an aqueous solution containing heavy metals, the polypeptides sequester the metals, removing them from the solution. There is selectivity of poly (.gamma.-glutamylcysteinyl)glycines having a particular number of monomer repeat unit for particular metals. The polypeptides are easily regenerated by contact with a small amount of an organic acid, so that they can be used again to remove heayv metals from solution. This also results in the removal of the metals from the column in a concentrated form.

Jackson, Paul J. (both Los Alamos, NM); Delhaize, Emmanuel (both Los Alamos, NM); Robinson, Nigel J. (Durham, GB2); Unkefer, Clifford J. (Los Alamos, NM); Furlong, Clement (Seattle, WA)

1990-11-13

233

Plants purify soils polluted with heavy metals  

Energy Technology Data Exchange (ETDEWEB)

Soils which are contaminated with heavy metals and contain health risks for people and animals, can be decontaminated biologically certain types of plants such as giant knotgrass, store large amounts of cadmium and lead, which can be removed agriculturally.

Haase, E.

1988-08-01

234

Removal of heavy metal ions from wastewater by a novel HEA/AMPS copolymer hydrogel: preparation, characterization, and mechanism.  

UK PubMed Central (United Kingdom)

This study aims to synthesize 2-hydroxyethyl acrylate (HEA) and 2-acrylamido-2-methylpropane sulfonic (AMPS) acid-based hydrogels by gamma radiation and to investigate their swelling behavior and heavy metal ion adsorption capabilities. The copolymer hydrogels prepared were characterized via scanning electron microscopy, Fourier transformed infrared spectra, thermal gravimetric analysis, and X-ray photoelectron spectroscopy. The research showed that the copolymer hydrogel was beneficial for permeation due to its porous structure. In addition, the experimental group A-2-d [70 % water volume ratio and (n (AMPS)/n (HEA))?=1:1] was an optimal adsorbent. The optimal pH was 6.0 and the optimal temperature was 15 °C. Pb(2+), Cd(2+), Cu(2+), and Fe(3)+ achieved adsorption equilibriums within 24 h, whereas Cr(3+) reached equilibrium in 5 h. Pb(2)+, Cd(2+), Cr(3+), and Fe(3+) maximum load capacity was 1,000 mg L(-1), whereas the Cu(2+) maximum capacity was 500 mg L(-1). The priority order in the multicomponent adsorption was Cr(3+)>Fe(3+)>Cu(2+)>Cd(2+)>Pb(2+). The adsorption process of the HEA/AMPS copolymer hydrogel for the heavy metal ions was mainly due to chemisorption, and was only partly due to physisorption, according to the pseudo-second-order equation and Langmuir adsorption isotherm analyses. The HEA/AMPS copolymer hydrogel was confirmed to be an effective adsorbent for heavy metal ion adsorption.

Li Z; Wang Y; Wu N; Chen Q; Wu K

2013-03-01

235

Heavy metals in plants and phytoremediation.  

UK PubMed Central (United Kingdom)

GOAL, SCOPE AND BACKGROUND: In some cases, soil, water and food are heavily polluted by heavy metals in China. To use plants to remediate heavy metal pollution would be an effective technique in pollution control. The accumulation of heavy metals in plants and the role of plants in removing pollutants should be understood in order to implement phytoremediation, which makes use of plants to extract, transfer and stabilize heavy metals from soil and water. METHODS: The information has been compiled from Chinese publications stemming mostly from the last decade, to show the research results on heavy metals in plants and the role of plants in controlling heavy metal pollution, and to provide a general outlook of phytoremediation in China. Related references from scientific journals and university journals are searched and summarized in sections concerning the accumulation of heavy metals in plants, plants for heavy metal purification and phytoremediation techniques. RESULTS AND DISCUSSION: Plants can take up heavy metals by their roots, or even via their stems and leaves, and accumulate them in their organs. Plants take up elements selectively. Accumulation and distribution of heavy metals in the plant depends on the plant species, element species, chemical and bioavailiability, redox, pH, cation exchange capacity, dissolved oxygen, temperature and secretion of roots. Plants are employed in the decontamination of heavy metals from polluted water and have demonstrated high performances in treating mineral tailing water and industrial effluents. The purification capacity of heavy metals by plants are affected by several factors, such as the concentration of the heavy metals, species of elements, plant species, exposure duration, temperature and pH. CONCLUSIONS: Phytoremediation, which makes use of vegetation to remove, detoxify, or stabilize persistent pollutants, is a green and environmentally-friendly tool for cleaning polluted soil and water. The advantage of high biomass productive and easy disposal makes plants most useful to remediate heavy metals on site. RECOMMENDATIONS AND OUTLOOK: Based on knowledge of the heavy metal accumulation in plants, it is possible to select those species of crops and pasturage herbs, which accumulate fewer heavy metals, for food cultivation and fodder for animals; and to select those hyperaccumulation species for extracting heavy metals from soil and water. Studies on the mechanisms and application of hyperaccumulation are necessary in China for developing phytoremediation.

Cheng S

2003-01-01

236

Removal of toxic heavy metal ions from waste water by functionalized magnetic core-zeolitic shell nanocomposites as adsorbents.  

UK PubMed Central (United Kingdom)

Functionalized magnetic core-zeolitic shell nanocomposites were prepared via hydrothermal and precipitation methods. The products were characterized by vibrating sample magnetometer, X-ray powder diffraction, Fourier transform infrared spectroscopy, nitrogen adsorption-desorption isotherms, and transmission electron microscopy analysis. The growth of mordenite nanocrystals on the outer surface of silica-coated magnetic nanoparticles at the presence of organic templates was well approved. The removal performance and the selectivity of mixed metal ions (Pb(2+) and Cd(2+)) in aqueous solution were investigated via the sorption process. The batch method was employed to study the sorption kinetic, sorption isotherms, and pH effect. The removal mechanism of metal ions was done by chem-phys sorption and ion exchange processes through the zeolitic channels and pores. The experimental data were well fitted by the appropriate kinetic models. The sorption rate and sorption capacity of metal ions could be significantly improved by optimizing the parameter values.

Padervand M; Gholami MR

2013-06-01

237

Heavy metals removal from acid mine drainage water using biogenic hydrogen sulphide and effluent from anaerobic treatment: Effect of pH  

Energy Technology Data Exchange (ETDEWEB)

Four alternatives (runs A, B, C and D) for heavy metals removal (Fe, Cu, Zn and Al) from acid mine drainage water (AMDW) produced in the mining areas of the Huelva Province, Spain, were evaluated. In run A, the anaerobic effluent from the treatment of acid mine drainage water (cheese whey added as a source of carbon) was mixed with the raw AMDW. The pH increased to 3.5 with the addition of KOH. In run B, biogas with around 30% of hydrogen sulphide obtained in the anaerobic reactor was sparged to the mixture obtained in run A, but in this case at a pH of 5.5. In run C, the pH of the raw AMDW was increased to 3.5 by the addition of KOH solution. Finally, in run D, the pH of the raw AMDW was increased to 5.5 by the addition of KOH solution and further biogas was sparged under the same conditions as in run A. It was found that heavy metal removal was a function of pH. At a pH of 3.5 most of the iron was removed while Zn and Cu were partially removed. At a pH of 5.5 the removal of all metals increased considerably. The best results were obtained in run B where the percentages of removal of Fe, Cu, Zn and Al achieved values of 91.3, 96.1, 79.0 and 99.0%, respectively. According to the experimental results obtained tentative schemas of the flow diagram of the processes were proposed.

Jimenez-Rodriguez, A.M. [Departamento de Sistemas Fisicos, Quimicos y Naturales, Facultad de Ciencias Ambientales, Universidad Pablo de Olavide. Carretera de Utrera, km 1. 41013 Sevilla (Spain); Duran-Barrantes, M.M. [Departamento de Ingenieria Quimica, Facultad de Quimica, Universidad de Sevilla, C/Profesor Garcia Gonzalez, s/n, 41071 Sevilla (Spain); Borja, R., E-mail: rborja@cica.es [Consejo Superior de Investigaciones Cientificas (CSIC), Instituto de la Grasa, Avda. Padre Garcia Tejero 4, 41012 Sevilla (Spain); Sanchez, E.; Colmenarejo, M.F. [Consejo Superior de Investigaciones Cientificas (CSIC), Centro de Ciencias Medioambientales, C/Serrano, 115-duplicado, 28006 Madrid (Spain); Raposo, F. [Consejo Superior de Investigaciones Cientificas (CSIC), Instituto de la Grasa, Avda. Padre Garcia Tejero 4, 41012 Sevilla (Spain)

2009-06-15

238

Capacidade da Lemna aequinoctialis para acumular metais pesados de água contaminada/ Ability of Lemna aequinoctialis for removing heavy metals from wastewater  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese A capacidade das plantas em tolerar e absorver quantidades elevadas de metais pesados é usada como uma tecnologia promissora para limpeza de resíduos perigosos em ambientes altamente contaminados. O desempenho da macrófita L. aequinoctialis em absorver metais pesados foi estudado durante sua floração em dois períodos de amostragem diferentes. As amostras de L. aequinoctialis e água foram coletadas por 800 horas em intervalos de 48 horas. A quantidade de Ni, Cu, Co, (more) Cr, Mn, Zn e Fe presente na L. aequinoctialis e água foram determinados por espectrometria de absorção atômica com chama (FAAS). Os resultados foram avaliados pelas técnicas de estatística de componentes principais (PCA), análise de agrupamento hierárquico (HCA) e boxplot. Os resultados mostram que a rizofiltração da L. aequinoctialis remove altas quantidades de metais pesados na seguinte ordem Cr > Ni > Cu > Fe > Zn > Mn. No entanto, observou-se que mudanças significativas na composição química, pH e condutividade elétrica da água alteram a capacidade de absorção da L. aequinoctialis. Abstract in english Plant ability for tolerating and accumulating high amount of heavy metal is used as a promissory technology for removing contaminants from highly polluted environments. The ability of the macrophyte L. aequinoctialis to remove heavy metal was studied in two different sampling times during its flowering. Samples of plant tissue L. aequinoctialis and water were collected for 800 hours at 48 hour intervals. Concentrations of Ni, Cu, Co, Cr, Mn, Zn, and Fe present in L. aequi (more) noctialis and water were determined by flame atomic absorption spectrometry (FAAS). Data were subjected to the techniques of principal components analysis (PCA), hierarchical cluster analysis (HCA) and boxplot. We found that rhizofiltration of L. aequinoctialis removes high amount of heavy metal in this order: Cr >Ni>Cu> Fe > Zn >Mn. Only significant changes in chemical composition of the water, pH and electrical conductivity alter the absorption capacity of L. aequinoctialis.

Pio, Mauro Célio da Silveira; Souza, Katiuscia dos Santos de; Santana, Genilson Pereira

2013-06-01

239

Use of low cost dead biomasses in the removal of heavy metal toxic/radiotoxic ions from aqueous wastes- a radiotracer study  

International Nuclear Information System (INIS)

In an environmental context, accelerating pollution by toxic metal ions, metalloids, radionuclides and organometal (loid)s has provided the impetus for the research to look into the biotechnological potential of utilizing several low cost dead biomasses/agricultural byproducts to replace existing expensive technologies. Unlike organic pollutants which are biodegradable, these metallic contaminants tend to persist rather indefinitely in the environment, and are eventually accumulated through the food chain thus posing a serious threat to plants, animal and man. The use of radiotracer technique by several workers and ourselves in the study of adsorption uptake or ions (cations and anions) from aqueous solutions by metals/metals oxide surfaces at micro down to tracer level concentrations had been quite rewarding. In continuation of this work the present studies were directed to assess the uptake behaviour of abundantly available low cost dead biomasses [e.g. Rice hulls (oryza sativa L),] Mango (mangifera indica) and Neem (azadirachta indica)barks] towards some heavy metal (Hg2+, Cd2+, Cr2+, Zn2+ and Ce3+) toxic and radiotoxic (Sr2+ and Csl+)ions from aqueous solutions at low ionic concentrations (10-2-10-8 mol dm-3). In all these studies the adsorptive solution was labeled by a suitable radiotracer of the metal ion and the uptake of ions by the three biosorbents was assessed through monitoring of the decrease in radioactivity of the bulk. A parametric study through change of temperature, pH and addition of other co-ions/complexing agents has helped in deducing the thermodynamic parameters and mechanism of the uptake of the ions. The extent of removal of metal ions by these dead biomasses is quite high in most cases and the nature of the uptake appears to be exchange type. These findings show that the agricultural byproducts (dead biomasses) can be utilized in the development of waste water treatment technology for removal of heavy metal toxic and radiotoxic ions. (author)

2005-01-01

240

Influence of pH on removal of heavy metallic cations by fly ash in aqueous solution  

Energy Technology Data Exchange (ETDEWEB)

Coal fly ash was used to study adsorption of several cations (Cu{sup 2+}, Ni{sup 2+}, Zn{sup 2+}, Cd{sup 2+}, Pb{sup 2+}, Cr (III)) within various experimental conditions: dry or wet fly ash, constant or not constant pH, metallic ion/fly ash mass ratio varying from 0.005 to 0.05. It was shown that alkalinity of fly ash, increasing pH to 11 for a fly ash concentration equal to 20 g l{sup -1} leads to higher removal capacity, due partly to bulk solution precipitation. Wet fly ash gives smaller adsorption capacity resulting from lost alkalinity and dissolution of alumina sites at pH 11. Removal order established in non-constant pH condition is: Pb {gt} Cu {gt} Ni {gt} Zn. Experiments carried out at several constant pH levels indicate that sorption capacities for metallic ions increase from 10%, or 40% to 100% when pH varies from 1 to 10. The removal order is: pH {gt} Cr {gt} Cu {gt} Ni {gt} Zn {gt} Cd. It was concluded that two groups of metallic cations should be distinguished: hydrolysing (CU{sup 2+}, Pb{sup 2+}) and non-hydrolysing (Ni{sup 2+}, Zn{sup 2+}). Lead, nickel, zinc and cadmium are certainly adsorbed in their free ionic form, even when both hydroxide species and free ionic forms are responsible for the removal of copper and chromium. However, removal affinity order separates easily hydrolyzable ions from less hydrolyzable ions.

Ricou, P.; Lecuyer, I.; Lecloirec, P. [Ecole des Mines de Nantes, Nantes (France)

1998-10-01

 
 
 
 
241

Removal of heavy metals and organic contaminants from aqueous streams by novel filtration methods. 1998 annual progress report  

Energy Technology Data Exchange (ETDEWEB)

'Graphite nanofibers are a new type of material consisting of nanosized graphite platelets where only edges are exposed. Taking advantage of this unique configuration the authors objective is: (1) To produce graphite nanofibers with structural properties suitable for the removal of contaminants from water. (2) To test the suitability of the material in the removal of organic from aqueous solutions. (3) To determine the ability of the nanofibers to function as an electrochemical separation medium the selective removal of metal contaminants from solutions. This report summarizes work after 1.5 of a 3-year project. During this period, efforts have been concentrated on the production, characterization and optimization of graphite nanofibers (GNF). This novel material has been developed in the laboratory from the metal catalyzed decomposition of certain hydrocarbons (1). The structures possess a cross-sectional area that varies between 5 to 100 nm and have lengths ranging from 5 to 100 mm (2). High-resolution transmission electron microscopy studies have revealed that the nanofibers consist of extremely well-ordered graphite platelets, which are oriented in various directions with respect to the fiber axis (3). The arrangement of the graphene layers can be tailored to a desired geometry by choice of the correct catalyst system and reaction conditions, and it is therefore possible to generate structures where the layers are stacked in a ribbon, herring-bone, or stacked orientation. The research has been directed on two fronts: (a) the use of the material for the removal of organic contaminants, and (b) taking advantage of the high electrical conductivity as well as high surface area of the material to use it as electrode for the electrochemical removal of metal pollutants from aqueous streams.'

Rodriguez, N.M.

1998-06-01

242

Photoactivated metal removal  

Energy Technology Data Exchange (ETDEWEB)

The authors propose the use of photochromic dyes as light activated switches to bind and release metal ions. This process, which can be driven by solar energy, can be used in environmental and industrial processes to remove metals from organic and aqueous solutions. Because the metals can be released from the ligands when irradiated with visible light, regeneration of the ligands and concentration of the metals may be easier than with conventional ion exchange resins. Thus, the process has the potential to be less expensive than currently used metal extraction techniques. In this paper, the authors report on their studies of the metal binding of spirogyran dyes and the hydrolytic stability of these dyes. They have prepared a number of spirogyrans and measured their binding constants for calcium and magnesium. They discuss the relationship of the structure of the dyes to their binding strengths. These studies are necessary towards determining the viability of this technique.

Nimlos, M.R.; Filley, J.; Ibrahim, M.A.; Watt, A.S.; Blake, D.M.

1999-07-01

243

Simultaneous removal of heavy-metal ions in wastewater samples using nano-alumina modified with 2,4-dinitrophenylhydrazine.  

UK PubMed Central (United Kingdom)

2,4-Dinitrophenylhydrazine (DNPH) immobilized on sodium dodecyl sulfate coated nano-alumina was developed for the removal of metal cations Pb(II), Cd(II), Cr(III), Co(II), Ni(II) and Mn(II) from water samples. The research results displayed that adsorbent has the highest adsorption capacity for Pb(II), Cr(III) and Cd(II) in ions mixture system. Optimal experimental conditions including pH, adsorbent dosage and contact time have been established. Langmuir and Freundlich isotherm models were applied to analyze the experimental data. The best interpretation for the experimental data was given by the Freundlich adsorption isotherm equation for Mn(II), Pb(II), Cr(III) and Cd(II) ions and by Langmuir isotherm equation for Ni(II) and Co(II) ions. Desorption experiments by elution of the adsorbent with a mixture of nitric acid and methanol show that the modified alumina nanoparticles could be reused without significant losses of its initial properties even after three adsorption-desorption cycles. Thus, modified nano-alumina with DNPH is favorable and useful for the removal of these metal ions, and the high adsorption capacity makes it a good promising candidate material for Pb(II),Cr(III) and Cd(II) removal.

Afkhami A; Saber-Tehrani M; Bagheri H

2010-09-01

244

Removal of Heavy Metals from Aqueous Solution Using Novel Nanoengineered Sorbents: Self-Assembled Carbamoylphosphonic Acids on Mesoporous Silica  

Energy Technology Data Exchange (ETDEWEB)

Self-assembled monolayers of carbamoylphosphonic acids (acetamide phosphonic acid and propionamide phosphonic acid) on mesoporous silica supports were studied as potential absorbents for heavy and transition metal ions in aqueous wastes. The adsorption capacity, selectivity, and kinetics of the materials in sequestering metal ions, including Cd2+, Co2+, Cu2+, Cr3+, Pb2+, Ni2+, Zn2+, and Mn2+, were measured in batch experiments with excess sodium ion. The solution pH ranged from 2.2 to 5.5. The kinetics study shows that the adsorption reached equilibrium in seconds, indicating that there is little resistance to mass transfer, intraparticle diffusion, and surface chemical reaction. The competitive adsorption study found the phosphonic acid-SAMMS to have an affinity for divalent metal ions in decreasing order of Pb2+ > Cu2+ > Mn2+ > Cd2+ > Zn2+ > Co2+ > Ni2+. The measured Cd2+ adsorption isotherm was of the Langmuirian type and had a saturation binding capacity of 0.32 mmol/g.

Yantasee, Wassana; Lin, Yuehe; Fryxell, Glen E.; Busche, Brad J.; Birnbaum, Jerome C.

2003-08-01

245

Application of Gamma Radiation to Enhance Heavy Metals Removal Efficiency to Bacteria Isolated from Ronpiboon District, Nakhon Sri Thamarat Province, Thailand  

International Nuclear Information System (INIS)

The objective of this study was to isolate soil bacteria capable to te move 4 heavy metals, namely, arsenic (As(III)), lead Pb(II) and cadmium f ron old tin mine in Ronpiboon district, Nakhon Sri Thamarat. It was found that there were bacteria which capable to resist arsenic, lead and copper 11, 15, 8 and 2 ileitis, respectively[evacuate;y. The arsenic removal efficiency of these bacteria was evaluated at the low concentration of 1 u g/l. with the results of 7-61%. The lead and copper removal efficiencies at 10 mg/l were found at the range pf 9-98% and 8-40%, respectively. Six isolates of bacteria (KRD, KRH, KRM, KCD13 and KCD14) were selected to be irradiated by gamma radiation at the levels of 2-10 kGy. The heavy metals resistance was found increase in the range of of 125-16% for arsenic, 0-50% for copper, 0-18% for lead and 0-17% for cadmium, respectively. Also ut was found that the low temperature at 4 and -40 degree Celsius can prolong the bacterial survival up to 6 months. Later the arsenic removal experiment in liquid medium was conducted and it was found that the mutants can perform slightly better than wild type only >17%. It was due to the initial concentration of arsenic was too high (10 mg/l). The preliminary study of arsenic removal in soil was also conducted using pack-bed reactor. We found the proper ratio of pack material (soil and gravel) was 1:1 to promote the liquid and air circulation. The suitable medium was found to be acidified mo lass solution which were found promote the growth of tested bacterial isolates.

2006-01-01

246

Adsorptive Removal of Arsenite as (III) and Arsenate as (V) Heavy Metals from Waste Water using Nigella sativa L.  

Directory of Open Access Journals (Sweden)

Full Text Available This study was focused on Nigella sativa Linn. as an alternative absorbent in order to remove As (III) and arsenate As (V) from synthetic waste water. As such, Nigella sativa L. was collected from Burydah A-Qassim. Batch experiments were conducted to determine the adsorptive efficiency of Nigella sativa L. to remove As (III) and arsenate As (V) from waste water. The preliminary experiments were revealed that alkaline solutions (pH>9) without Nigella sativa L. caused homogeneous oxidation of As (III) to As (V) so the adsorption process was investigated at pH range 2-8. The batch experiments were revealed that adsorption of As ion on Nigella sativa L. was maximal at low pH (at a 3.0) value. The adsorption studies revealed that the ongoing adsorption validates Langmuir adsorption isotherms at temperatures 25, 35 and 45°C. The adsorption isotherm data was also employed to calculate the thermodynamic parameter of Gibb’s free energy which gives a negative value for the adsorption of As ion on Nigella sativa L. The negative values of free energy indicate the feasibility and spontaneous nature of the adsorption process. From these results, it can be concluded that the Nigella sativa L. could be a good adsorbent for the removal of cationic metals coming from waste water.

S.M. El-Said; M.B.S. Alamri; Ali-Bin Saleh El-Barak; O. Alsogair

2009-01-01

247

Application of a new generation of complexing agents in removal of heavy metal ions from different wastes.  

Science.gov (United States)

Complexing agents are extensively applied in many fields of industry. They are used to provide effective controlling trace metal ions in cleaning industries, textile, pulp and paper production, water treatment, agriculture, food industries, etc. Recently, the low biodegradability of these ligands and their accumulation in the environment has become a cause for concern. Therefore, replacement of ethylenediaminetetraacetic acid and diethylenetriaminepentaacetic acid by more environmentally friendly chelating agents is highly desirable. So far, these acids and their salts have been applied as components of household chemistry, cosmetics, modern microelement fertilizers and agrochemicals. This paper reviews the sorption of heavy metal ions such as Cu(II), Zn(II), Cd(II) and Pb(II) in the presence of the above-mentioned complexing agents on commercially available anion exchangers of different matrix. The obtained sorption results were fitted using the Langmuir and Freundlich sorption isotherm models. The kinetic data were also analysed using the Lagergren, Ho and McKay sorption kinetic equations. The studies were carried out considering the effects of such important parameters as phase contact time, initial concentration, pH and temperature. PMID:23463276

Ko?ody?ska, Dorota

2013-03-06

248

Synthesis of MnFe2O4@Mn-Co oxide core-shell nanoparticles and their excellent performance for heavy metal removal.  

Science.gov (United States)

Magnetic nanomaterials that can be easily separated and recycled due to their magnetic properties have received considerable attention in the field of water treatment. However, these nanomaterials usually tend to aggregate and alter their properties. Herein, we report an economical and environmentally friendly method for the synthesis of magnetic nanoparticles with core-shell structure. MnFe2O4 nanoparticles have been successfully coated with amorphous Mn-Co oxide shells. The synthesized MnFe2O4@Mn-Co oxide nanoparticles have highly negatively charged surface in aqueous solution over a wide pH range, thus preventing their aggregation and enhancing their performance for heavy metal cation removal. The adsorption isotherms are well fitted to a Langmuir adsorption model, and the maximal adsorption capacities of Pb(ii), Cu(ii) and Cd(ii) on MnFe2O4@Mn-Co oxide are 481.2, 386.2 and 345.5 mg g(-1), respectively. All the metal ions can be completely removed from the mixed metal ion solutions in a short time. Desorption studies confirm that the adsorbent can be effectively regenerated and reused. PMID:23945878

Ma, Zichuan; Zhao, Dongyuan; Chang, Yongfang; Xing, Shengtao; Wu, Yinsu; Gao, Yuanzhe

2013-09-18

249

Removal of multi-heavy metals using biogenic manganese oxides generated by a deep-sea sedimentary bacterium - Brachybacterium sp. strain Mn32.  

UK PubMed Central (United Kingdom)

A deep-sea manganese-oxidizing bacterium, Brachybacterium sp. strain Mn32, showed high Mn(II) resistance (MIC 55 mM) and Mn(II)-oxidizing/removing abilities. Strain Mn32 removed Mn(II) by two pathways: (1) oxidizing soluble Mn(II) to insoluble biogenic Mn oxides - birnessite (delta-MnO(2) group) and manganite (gamma-MnOOH); (2) the biogenic Mn oxides further adsorb more Mn(II) from the culture. The generated biogenic Mn oxides surround the cell surfaces of strain Mn32 and provide a high capacity to adsorb Zn(II) and Ni(II). Mn(II) oxidation by strain Mn32 was inhibited by both sodium azide and o-phenanthroline, suggesting the involvement of a metalloenzyme which was induced by Mn(II). X-ray diffraction analysis showed that the crystal structures of the biogenic Mn oxides were different from those of commercial pyrolusite (beta-MnO(2) group) and fresh chemically synthesized vernadite (delta-MnO(2) group). The biogenic Mn oxides generated by strain Mn32 showed two to three times higher Zn(II) and Ni(II) adsorption abilities than commercial and fresh synthetic MnO(2). The crystal structure and the biogenic MnO(2) types may be important factors for the high heavy metal adsorption ability of strain Mn32. This study provides potential applications of a new marine Mn(II)-oxidizing bacterium in heavy metal bioremediation and increases our basic knowledge of microbial manganese oxidation mechanisms.

Wang W; Shao Z; Liu Y; Wang G

2009-06-01

250

Removal of multi-heavy metals using biogenic manganese oxides generated by a deep-sea sedimentary bacterium - Brachybacterium sp. strain Mn32.  

Science.gov (United States)

A deep-sea manganese-oxidizing bacterium, Brachybacterium sp. strain Mn32, showed high Mn(II) resistance (MIC 55 mM) and Mn(II)-oxidizing/removing abilities. Strain Mn32 removed Mn(II) by two pathways: (1) oxidizing soluble Mn(II) to insoluble biogenic Mn oxides - birnessite (delta-MnO(2) group) and manganite (gamma-MnOOH); (2) the biogenic Mn oxides further adsorb more Mn(II) from the culture. The generated biogenic Mn oxides surround the cell surfaces of strain Mn32 and provide a high capacity to adsorb Zn(II) and Ni(II). Mn(II) oxidation by strain Mn32 was inhibited by both sodium azide and o-phenanthroline, suggesting the involvement of a metalloenzyme which was induced by Mn(II). X-ray diffraction analysis showed that the crystal structures of the biogenic Mn oxides were different from those of commercial pyrolusite (beta-MnO(2) group) and fresh chemically synthesized vernadite (delta-MnO(2) group). The biogenic Mn oxides generated by strain Mn32 showed two to three times higher Zn(II) and Ni(II) adsorption abilities than commercial and fresh synthetic MnO(2). The crystal structure and the biogenic MnO(2) types may be important factors for the high heavy metal adsorption ability of strain Mn32. This study provides potential applications of a new marine Mn(II)-oxidizing bacterium in heavy metal bioremediation and increases our basic knowledge of microbial manganese oxidation mechanisms. PMID:19383675

Wang, Wenming; Shao, Zongze; Liu, Yanjun; Wang, Gejiao

2009-04-21

251

Removal of Heavy Metal Ions by Using Composite of Cement Kiln Dust/Ethylene Glycol co Acrylic Acid Prepared by y-Irradiation  

International Nuclear Information System (INIS)

Various composites of cement kiln dust (CKD) and poly(ethylene glycol co acrylic acid) using y-irradiation was investigated. The samples were prepared using three percentages of cement kiln dust namely, 20, 50 and 75 by wt % and mixed with an equimolar ratio (1:1) of ethylene glycol and acrylic acid then irradiated at doses; 10,20 and 30 kGy of gamma-irradiation. The results showed that (CKD) and poly(ethylene glycol co acrylic acid) composites were formed only at 30 kGy. In addition, CKD alone has the lowest degree of removal of heavy metal ions compared with the prepared composites. A composite containing 75% cement kiln dust by weight percentage, showed the highest degree of removal of cobalt ions, whereas, a composite of 20% CKD showed the highest degree for cadmium ion removal. While the composite of 75% CKD showed a higher selectivity of cobalt ion than cadmium ion in their mixed solution.

2010-01-01

252

Hydroponics reducing effluent's heavy metals discharge.  

UK PubMed Central (United Kingdom)

This paper investigates the capacity of Nutrient Film Technique (NFT) to control effluent's heavy metals discharge. A commercial hydroponic system was adapted to irrigate lettuces with primary treated wastewater for studying the potential heavy metals removal. A second commercial hydroponic system was used to irrigate the same type of lettuces with nutrient solution and this system was used as a control. Results showed that lettuces grew well when irrigated with primary treated effluent in the commercial hydroponic system. The NFT-plant system heavy metals removal efficiency varied amongst the different elements, The system's removal efficiency for Cr was more than 92%, Ni more than 85%, in addition to more than 60% reduction of B, Pb, and Zn. Nonetheless, the NFT-plants system removal efficiencies for As, Cd and Cu were lower than 30%. Results show that lettuces accumulated heavy metals in leaves at concentrations higher than the maximum acceptable European and Australian levels. Therefore, non-edible plants such as flowers or pyrethrum are recommended as value added crops for the proposed NFT.

Rababah A; Al-Shuha A

2009-01-01

253

Hydroponics reducing effluent's heavy metals discharge.  

Science.gov (United States)

This paper investigates the capacity of Nutrient Film Technique (NFT) to control effluent's heavy metals discharge. A commercial hydroponic system was adapted to irrigate lettuces with primary treated wastewater for studying the potential heavy metals removal. A second commercial hydroponic system was used to irrigate the same type of lettuces with nutrient solution and this system was used as a control. Results showed that lettuces grew well when irrigated with primary treated effluent in the commercial hydroponic system. The NFT-plant system heavy metals removal efficiency varied amongst the different elements, The system's removal efficiency for Cr was more than 92%, Ni more than 85%, in addition to more than 60% reduction of B, Pb, and Zn. Nonetheless, the NFT-plants system removal efficiencies for As, Cd and Cu were lower than 30%. Results show that lettuces accumulated heavy metals in leaves at concentrations higher than the maximum acceptable European and Australian levels. Therefore, non-edible plants such as flowers or pyrethrum are recommended as value added crops for the proposed NFT. PMID:19151500

Rababah, Abdellah; Al-Shuha, Ahmad

2009-01-01

254

Biological effects of heavy metals  

Energy Technology Data Exchange (ETDEWEB)

This review focuses on the interaction between metals and biological systems. Its scope ranges from problems of trace metal analysis in biological matrices to metal metabolism in plants and animals;from the role of metals in nutrition of the nature of their toxic effects;and from routes of exposure to clinical problems. While primarily dealing with heavy metals, other toxic metals are also considered.

Foulkes, E.C. (Dept of Environmental Health, Kettering Lab., Univ. of Cincinnati, Cincinnati, OH (US))

1990-01-01

255

Prediction of Heavy Metal Removal by Different Liner Materials from Landfill Leachate: Modeling of Experimental Results Using Artificial Intelligence Technique  

Science.gov (United States)

An intensive study has been made to see the performance of the different liner materials with bentonite on the removal efficiency of Cu(II) and Zn(II) from industrial leachate. An artificial neural network (ANN) was used to display the significant levels of the analyzed liner materials on the removal efficiency. The statistical analysis proves that the effect of natural zeolite was significant by a cubic spline model with a 99.93% removal efficiency. Optimization of liner materials was achieved by minimizing bentonite mixtures, which were costly, and maximizing Cu(II) and Zn(II) removal efficiency. The removal efficiencies were calculated as 45.07% and 48.19% for Cu(II) and Zn(II), respectively, when only bentonite was used as liner material. However, 60% of natural zeolite with 40% of bentonite combination was found to be the best for Cu(II) removal (95%), and 80% of vermiculite and pumice with 20% of bentonite combination was found to be the best for Zn(II) removal (61.24% and 65.09%). Similarly, 60% of natural zeolite with 40% of bentonite combination was found to be the best for Zn(II) removal (89.19%), and 80% of vermiculite and pumice with 20% of bentonite combination was found to be the best for Zn(II) removal (82.76% and 74.89%).

Turan, Nurdan Gamze; Gumusel, Emine Beril; Ozgonenel, Okan

2013-01-01

256

Prediction of heavy metal removal by different liner materials from landfill leachate: modeling of experimental results using artificial intelligence technique.  

UK PubMed Central (United Kingdom)

An intensive study has been made to see the performance of the different liner materials with bentonite on the removal efficiency of Cu(II) and Zn(II) from industrial leachate. An artificial neural network (ANN) was used to display the significant levels of the analyzed liner materials on the removal efficiency. The statistical analysis proves that the effect of natural zeolite was significant by a cubic spline model with a 99.93% removal efficiency. Optimization of liner materials was achieved by minimizing bentonite mixtures, which were costly, and maximizing Cu(II) and Zn(II) removal efficiency. The removal efficiencies were calculated as 45.07% and 48.19% for Cu(II) and Zn(II), respectively, when only bentonite was used as liner material. However, 60% of natural zeolite with 40% of bentonite combination was found to be the best for Cu(II) removal (95%), and 80% of vermiculite and pumice with 20% of bentonite combination was found to be the best for Zn(II) removal (61.24% and 65.09%). Similarly, 60% of natural zeolite with 40% of bentonite combination was found to be the best for Zn(II) removal (89.19%), and 80% of vermiculite and pumice with 20% of bentonite combination was found to be the best for Zn(II) removal (82.76% and 74.89%).

Turan NG; Gümü?el EB; Ozgonenel O

2013-01-01

257

Plant rhamnogalacturonan II complexation of heavy metal cations  

Energy Technology Data Exchange (ETDEWEB)

The present invention provides rhamnogalacturonan-II (RG-II) and relates to its ability to complex specific multivalent heavy metal cations. In the presence of boric acid, RG-II monomers form dimers that are cross-linked by a borate ester. The yield of such borate ester cross-linked dimers of RG-II is enhanced in the presence of specific heavy metal cations. The present invention further relates to the utility of RG-II in assays for the detection of specific heavy metal contamination; as a reagent useful in the removal of specific heavy metal cations contaminating foods and liquids, for example, fish, wines, etc.; as a pharmaceutical composition useful as an antidote in specific heavy metal cation poisoning; as a treatment for the detoxification of specific heavy metal cations from blood and/or tissues; and in a method of remediation of waters and soils contaminated with specific heavy metal cations.

O' Neill, Malcolm A. (Winterville, GA); Pellerin, Patrice J. M. (Montpellier, FR); Warrenfeltz, Dennis (Athens, GA); Vidal, Stephane (Combaillaux, FR); Darvill, Alan G. (Athens, GA); Albersheim, Peter (Athens, GA)

1999-01-01

258

A critical review on the bio-removal of hazardous heavy metals from contaminated soils: issues, progress, eco-environmental concerns and opportunities.  

UK PubMed Central (United Kingdom)

Mechanism of four methods for removing hazardous heavy metal are detailed and compared-chemical/physical remediation, animal remediation, phytoremediation and microremediation with emphasis on bio-removal aspects. The latter two, namely the use of plants and microbes, are preferred because of their cost-effectiveness, environmental friendliness and fewer side effects. Also the obvious disadvantages of other alternatives are listed. In the future the application of genetic engineering or cell engineering to create an expected and ideal species would become popular and necessary. However, a concomitant and latent danger of genetic pollution is realized by a few persons. To cope with this potential harm, several suggestions are put forward including choosing self-pollinated plants, creating infertile polyploid species and carefully selecting easy-controlled microbe species. Bravely, the authors point out that current investigation of noncrop hyperaccumulators is of little significance in application. Pragmatic development in the future should be crop hyperaccumulators (newly termed as "cropaccumulators") by transgenic or symbiotic approach. Considering no effective plan has been put forward by others about concrete steps of applying a hyperaccumulator to practice, the authors bring forward a set of universal procedures, which is novel, tentative and adaptive to evaluate hyperaccumulators' feasibility before large-scale commercialization.

Wu G; Kang H; Zhang X; Shao H; Chu L; Ruan C

2010-02-01

259

Heavy Metal Pumps in Plants  

Energy Technology Data Exchange (ETDEWEB)

The long term goal of the funded research is to understand how heavy metals are taken up from the soil and translocated throughout the plant. The potential application of this research is to create plants with better heavy metal uptake systems and thereby improve the ability of these plants to help clean up toxic metals from soils. A rate limiting step is using plant for bioremediation is the normally poor capacity of plants to concentrate toxic metals. Our interest in metal ion transport systems includes those for essential mineral nutrients such as molybdenum, copper, iron, manganese, as well as toxic metals such as cerium, mercury, cesium, cadmium, arsenic and selenium. Understanding the pathways by which toxic metals accumulate in plants will enable the engineering of plants to exclude toxic metals and create healthier food sources, or to extract toxic metals from the soil as a strategy to clean up polluted lands and water.

Harper, J.F.

2000-10-01

260

Phytoremediation of heavy-metal-polluted soils: screening for new accumulator plants in Angouran mine (Iran) and evaluation of removal ability.  

Science.gov (United States)

Heavy metal pollution is a worldwide problem. Phytoremediation is an effective and low-cost interesting technology. This study was conducted in a dried waste pool of a lead and zinc mine in Angouran (Iran) to find accumulator plant(s). Concentrations of heavy metals were determined both in the soil and the plants that were grown in the mine and out of mine. The concentration of total Cu, Fe, Zn, Pb and Ni in the mine area were higher than the control soil. The results showed that five dominant vegetations namely Amaranthus retroflexus, Polygonum aviculare, Gundelia tournefortii, Noea mucronata and Scariola orientalis accumulated heavy metals. Based on the results, it was concluded that N. mucronata is the best accumulator for Pb, Zn, Cu, Cd and Ni, but the best Fe accumulator is A. retroflexus. Phytoremediation ability of N. mucronata was evaluated in experimental pots. The study showed that the amounts of heavy metals were decreased in polluted soils during experiments. The accumulation of metals in the root, leave and shoot portions of N. mucronata varied significantly but all the concentrations were more than natural soils. The results indicated that N. mucronata is an effective accumulator plant for phytoremediation of heavy-metals-polluted soils. PMID:19386362

Chehregani, Abdolkarim; Noori, Mitra; Yazdi, Hossein Lari

2009-04-21

 
 
 
 
261

Phytoremediation of heavy-metal-polluted soils: screening for new accumulator plants in Angouran mine (Iran) and evaluation of removal ability.  

UK PubMed Central (United Kingdom)

Heavy metal pollution is a worldwide problem. Phytoremediation is an effective and low-cost interesting technology. This study was conducted in a dried waste pool of a lead and zinc mine in Angouran (Iran) to find accumulator plant(s). Concentrations of heavy metals were determined both in the soil and the plants that were grown in the mine and out of mine. The concentration of total Cu, Fe, Zn, Pb and Ni in the mine area were higher than the control soil. The results showed that five dominant vegetations namely Amaranthus retroflexus, Polygonum aviculare, Gundelia tournefortii, Noea mucronata and Scariola orientalis accumulated heavy metals. Based on the results, it was concluded that N. mucronata is the best accumulator for Pb, Zn, Cu, Cd and Ni, but the best Fe accumulator is A. retroflexus. Phytoremediation ability of N. mucronata was evaluated in experimental pots. The study showed that the amounts of heavy metals were decreased in polluted soils during experiments. The accumulation of metals in the root, leave and shoot portions of N. mucronata varied significantly but all the concentrations were more than natural soils. The results indicated that N. mucronata is an effective accumulator plant for phytoremediation of heavy-metals-polluted soils.

Chehregani A; Noori M; Yazdi HL

2009-07-01

262

Desarrollo de membranas de quitosano y diseño de un equipo para la eliminación de metales pesados del agua Chitosan membrane development and design of equipment for the removal of heavy metals from water  

Directory of Open Access Journals (Sweden)

Full Text Available El presente estudio comparó la eficiencia de la filtración con membranas de quitosano 1,75% m/v, entrecruzadas con glutaraldehído (0,08% m/v) y sin entrecruzar, para estimar la capacidad de remoción de iones de cadmio, cromo y cobre de disoluciones modelo. Además, se diseñó un equipo de bajo costo para la experimentación con las membranas elaboradas. La finalidad de la investigación era emplear materiales biodegradables para remover metales pesados de aguas, mediante una técnica de bajo consumo energético y, por otra parte, generar soluciones baratas, efectivas y aplicables a problemas específicos. Se elaboraron dos fichas técnicas con información sobre las membranas y se encontró que el cromo fue el metal removido en mayor medida por las membranas entrecruzadas, ajustándose al modelo de isoterma de Freundlich. Sin embargo, no se encontró relación entre el tamaño de poro de las membranas y el grado de entrecruzamiento.A filtration technique with 1,75% m/v chitosan membranes crosslinked with glutaraldehyde (0,08% v/v) was used to quantify the removal capacity of chromium, copper and cadmium ions from water. A simple and low cost filtration system was developed to use with prepared membranes.The main goal was to use biodegradable materials for removing heavy metals from water, through a low energy consumption, cheap, and specific method.As a result, two data sheets were prepared for the membranes. It was found out that chromium was the metal with the highest removal from water, by using a crosslinked membrane. Metal adsorption was best adjusted to the Freundlich isotherm model, better than Langmuir isotherm model.However, it was found no correlation between pore size and crosslinking degree.

Jesús Mora Molina; Luis Chaves Barquero; Mario Araya Marchena; Ricardo Starbird Pérez

2012-01-01

263

Adsorptive Removal of Arsenite as (III) and Arsenate as (V) Heavy Metals from Waste Water using Nigella sativa L.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This study was focused on Nigella sativa Linn. as an alternative absorbent in order to remove As (III) and arsenate As (V) from synthetic waste water. As such, Nigella sativa L. was collected from Burydah A-Qassim. Batch experiments were conducted to determine the adsorptive efficiency...

S.M. El-Said; M.B.S. Alamri; Ali-Bin Saleh El-Barak; O. Alsogair

264

Inorganic particulates in removal of toxic heavy metal ions: Part-X. removal behaviour of aluminum hydroxide for Hg(II) - a radiotracer study  

International Nuclear Information System (INIS)

The present paper deals with a study on the removal behaviour of amorphous-type aluminum hydroxide for Hg(II) at micro to tracer level concentrations from aqueous solutions by employing the radiotracer technique. The solid/solution interface study was carried out for various physico-chemical parameters, e.g., effect of concentration, temperature and pH. The effect of the presence of several added cations/anions towards its removal behaviour was also assessed

2006-01-01

265

Aqueous heavy metals removal on amine-functionalized Si-MCM-41 and Si-MCM-48  

International Nuclear Information System (INIS)

[en] Ordered mesoporous silica with hexagonal and cubic structure, type MCM-41 and MCM-48 respectively, were synthesized under basic media using pure silica, cetyltrimethylammonium bromide and tetramethylammonium hydroxide, for MCM-41 and tetraethylorthosilica, cetyltrimethylammonium and NaOH for MCM-48. The expanded materials were prepared by post-synthesis method with N-N dimethyldodecylamine (DMDDA) and dodecylamine (DDA). Small angle X-ray diffraction, nitrogen adsorption-desorption measurements, FT-IR and thermogravimetry were used to characterize the samples. The expanded materials were tested for adsorption of Cd2+, Co2+, Cu2+ and Pb2+ in aqueous solution. Aminated materials were found to be fast adsorbents for metallic ions cation with affinity for Cu2+, Pb2+, than for Cd2+ and Co2+ from single solution. In mixed metallic ions cation solutions, competition by the adsorption sites is likely to occur, the adsorption preference is for Cu2+and Pb2+. The kinetic of the reaction is very rapid and follow pseudo-second order and clearly indicated that Langmuir model describe better the for metal ions adsorption on aminated mesoporous material than Freundlich model.

2009-11-15

266

Electrocinetic removal of heavy metals from fine-grained contaminated soils; Elektrokinetische Entfernung von Schwermetallen aus feinkoernigen kontaminierten Boeden  

Energy Technology Data Exchange (ETDEWEB)

Laboratory investigations have shown that lead can be removed from fine-grained soils by an electrokinetic process. For this purpose, d.c. voltage is applied to electrodes which induce the lead to migrate to the cathode. The method and the results achieved so far are described and evaluated. [Deutsch] In Laboruntersuchungen wurde festgestellt, dass Blei aus einem feinkoernigen Boden elektrokinetisch entfernt werden kann. Dazu wird eine Gleichspannung an Elektroden angebracht, die eine Wanderung des Bleis zur Kathode bewirken. Das Verfahren und die beobachteten Werte werden beschrieben und bewertet. (orig.)

Oey, W.; Azzam, R. [Technische Univ. Bergakademie Freiberg (Germany). Inst. fuer Geotechnik

1999-06-01

267

Screening the possibility for removing cadmium and other heavy metals from wastewater sludge and bio-ashes by an electrodialytic method  

International Nuclear Information System (INIS)

Both wastewater sludge and fly ash from combustion of biomass (bio-ash) have traditionally been applied to agricultural land in Denmark. However, Cd concentrations often exceed limiting values. The present study is a preliminary investigation of the possibility for reducing the Cd concentration in wastewater sludge and bio-ashes (straw and wood) using an electrodialytic method. The waste products were treated as stirred suspensions. During the remediation the suspension was acidified from water splitting at the anion exchange membrane and the acidification mobilized Cd that was removed to the electrode compartments. Even though the matrices were very different the remediation was successful in all cases. After treatment the Cd concentration in the ashes allowed for spreading at agricultural land and the limiting concentration of 0.8 mg Cd/kg for the wastewater sludge was almost reached (0.84 and 0.88 mg Cd/kg). The main differences of the waste products influencing the remediation process were: the sludges had a high content of organic particles that were mobilized by electrophoresis and fouled the anion exchange membrane; the straw-ash contained a lot of chloride, which formed anionic complexes with Cd, and the wood ash had a high initial pH (13.3). The mass of wastewater sludge and bio-ashes decreased during treatment but the concentration of other heavy metals (Pb, Ni, Cu and Zn) was not increased to exceed limiting values in remediated matrix.

2007-02-25

268

Electrospun Fe2O3-Al2O3 nanocomposite fibers as efficient adsorbent for removal of heavy metal ions from aqueous solution.  

UK PubMed Central (United Kingdom)

In this study, Iron oxide-alumina mixed nanocomposite fiber was prepared by electrospinning method and its performance was evaluated as a heavy metal ion adsorbent. Here boehmite nanoparticle was synthesized by sol-gel method and was impregnated in PVP-iron acetylacetonate solution in a ratio of 1:1:2. These boehmite impregnated polymer solution was electrospun to form nanocomposite polymer fiber. The electrospun nanofiber was sintered at 1000°C for converting it to pure oxide form for further application as adsorbent. Iron oxide-alumina mixed nanocomposite fiber was characterized by UV-vis-DRS, IR, SEM-EDX, TEM, BET and TGA-DTA analytical techniques. Batch adsorption experiments were carried out to study the sorption behavior of Cu(2+), Pb(2+), Ni(2+) and Hg(2+) ions as a function of initial concentration, contact time and pH. The removal percentage was in the order of Cu(2+)

Mahapatra A; Mishra BG; Hota G

2013-08-01

269

Screening the possibility for removing cadmium and other heavy metals from wastewater sludge and bio-ashes by an electrodialytic method  

DEFF Research Database (Denmark)

Both wastewater sludge and fly ash from combustion of biomass (bio-ash) have traditionally been applied to agricultural land in Denmark. However, Cd concentrations often exceed limiting values. The present study is a preliminary investigation of the possibility for reducing the Cd concentration in wastewater sludge and bio-ashes (straw and wood) using an electrodialytic method. The waste products were treated as stirred suspensions. During the remediation the suspension was acidified from water splitting at the anion exchange membrane and the acidification mobilized Cd that was removed to the electrode compartments. Even though the matrices were very different the remediation was successful in all cases. After treatment the Cd concentration in the ashes allowed for spreading at agricultural land and the limiting concentration of 0.8mgCd/kg for the wastewater sludge was almost reached (0.84 and 0.88mgCd/kg). The main differences of the waste products influencing the remediation process were: the sludges had a high content of organic particles that were mobilized by electrophoresis and fouled the anion exchange membrane; the straw-ash contained a lot of chloride, which formed anionic complexes with Cd, and the wood ash had a high initial pH (13.3). The mass of wastewater sludge and bio-ashes decreased during treatment but the concentration of other heavy metals (Pb, Ni, Cu and Zn) was not increased to exceed limiting values in remediated matrix.

Ottosen, Lisbeth M.; Pedersen, Anne Juul

2007-01-01

270

Electrospun Fe2O3-Al2O3 nanocomposite fibers as efficient adsorbent for removal of heavy metal ions from aqueous solution.  

Science.gov (United States)

In this study, Iron oxide-alumina mixed nanocomposite fiber was prepared by electrospinning method and its performance was evaluated as a heavy metal ion adsorbent. Here boehmite nanoparticle was synthesized by sol-gel method and was impregnated in PVP-iron acetylacetonate solution in a ratio of 1:1:2. These boehmite impregnated polymer solution was electrospun to form nanocomposite polymer fiber. The electrospun nanofiber was sintered at 1000°C for converting it to pure oxide form for further application as adsorbent. Iron oxide-alumina mixed nanocomposite fiber was characterized by UV-vis-DRS, IR, SEM-EDX, TEM, BET and TGA-DTA analytical techniques. Batch adsorption experiments were carried out to study the sorption behavior of Cu(2+), Pb(2+), Ni(2+) and Hg(2+) ions as a function of initial concentration, contact time and pH. The removal percentage was in the order of Cu(2+)

Mahapatra, A; Mishra, B G; Hota, G

2013-05-04

271

Effect of two heavy metals, cadmium and nickel, on the organic load removal efficiency in a laboratory UASB reactor  

International Nuclear Information System (INIS)

Experiments were carried out in three up flow anaerobic sludge blanket, UASB, reactors each with 3 L capacity, four hours of hydraulic retention time, (HRT) and volumetric organic load of 4,8 g/L/d. After the initial start phase, which was of 4.000 hours for the three reactors, they were affected in the following way: the first reactor was continuously feed with 5 mg/L of cadmium chloride, the second one was continuously feed with 10 mg/L of nickel chloride and the last one was not affected and served as reference. Efficiency in organic load removal was measured as oxygen chemical demand (OCD), the first reactor changed from 60% in the start phase (phase one) to 18% in the cadmium-affected phase (phase two), efficiency in removal (OCI) in reactor two varied from 60 to 24% and the last one did not change in a noticeable manner. Reactor one accumulated cadmium in the mud, whereas reactor two did not do that with nickel

2004-01-01

272

Chemically modified olive stone: A low-cost sorbent for heavy metals and basic dyes removal from aqueous solutions  

International Nuclear Information System (INIS)

In the present work, we have investigated the sorption efficiency of treated olive stones (TOS) towards cadmium and safranine removal from their respective aqueous solutions. TOS material was prepared by treatment of olive stones with concentrated sulfuric acid at room temperature followed up by a subsequent neutralization with 0.1 M NaOH aqueous solution. The resulting material has been thoroughly characterized by SEM, energy-dispersive X-ray (EDX), MAS 13C NMR, FTIR and physicochemical parameters were calculated. The sorption study of TOS at the solid-liquid interface was investigated using kinetics, sorption isotherms, pH effect and thermodynamic parameters. The preliminary results indicate that TOS exhibit a better efficiency in terms of sorption capacities toward the two pollutants (128.2 and 526.3 mg/g for cadmium and safranine, respectively) than those reported so far in the literature. Moreover, the sorption process is ascertained to occur fast enough so that the equilibrium is reached in less than 15 min of contact time. The results found in the course of this study suggest that ion exchange mechanism is the most appropriate mechanism involved in cadmium and safranine removal. Finally, the sorption efficiency of TOS is compared to those of other low-cost sorbents materials yet described in the literature.

2009-04-15

273

Metals removal from spent salts  

Energy Technology Data Exchange (ETDEWEB)

A method and apparatus for removing metal contaminants from the spent salt of a molten salt oxidation (MSO) reactor is described. Spent salt is removed from the reactor and analyzed to determine the contaminants present and the carbonate concentration. The salt is dissolved in water, and one or more reagents may be added to precipitate the metal oxide and/or the metal as either metal oxide, metal hydroxide, or as a salt. The precipitated materials are filtered, dried and packaged for disposal as waste or can be immobilized as ceramic pellets. More than about 90% of the metals and mineral residues (ashes) present are removed by filtration. After filtration, salt solutions having a carbonate concentration >20% can be spray-dried and returned to the reactor for re-use. Salt solutions containing a carbonate concentration <20% require further clean-up using an ion exchange column, which yields salt solutions that contain less than 1.0 ppm of contaminants.

Hsu, Peter C. (Pleasanton, CA); Von Holtz, Erica H. (Livermore, CA); Hipple, David L. (Livermore, CA); Summers, Leslie J. (Livermore, CA); Brummond, William A. (Livermore, CA); Adamson, Martyn G. (Danville, CA)

2002-01-01

274

Removal of Heavy Metals Fe3+, Cu2+, Zn2+, Pb2+, Cr3+ and Cd2+ from Aqueous Solutions by Using Eichhornia Crassipes  

Directory of Open Access Journals (Sweden)

Full Text Available The adsorption capacity of Eichhornia Crassipes towards metal ions such as Fe3+, Cu2+, Zn2+, Pb2+, Cr3+ and Cd2+, was studied. The adsorption capacity was investigated by batch experiments. The results showed that the removal percentages increased as the weight of sorbent increased, except for Fe3+ and Zn2+. The effect of contact time was also studied and the results showed that the removal percentages increased as the contact time increased for Cr3+, Zn2+ and Pb2+, but for Fe3+, Cu2+ and Cd2+ the removal decreased. The effect of pH of the solution was also studied and the removal percentages increased as pH increased. Also the effect of the initial concentration of metal ions was studied at four different concentrations (5, 10, 30, 50 mg/L); in case of metal ions (Cu2+, Zn2+ and Cd2+) the removal percentages increased by increasing initial concentration. But, for the other metal ions it decreased by increasing initial concentration over 30 mg/L. The order of increasing removal percentages of metal ions at pH=4.86, initial concentration of metal ions 30 mg/L, and after four hours of shaking was: Cu2+< Cr3+

S.A. Shama; M.E. Moustafa; M.A. Gad

2010-01-01

275

Synthesis of a novel silica-supported dithiocarbamate adsorbent and its properties for the removal of heavy metal ions.  

Science.gov (United States)

Silica-supported dithiocarbamate adsorbent (Si-DTC) was synthesized by anchoring the chelating agent of macromolecular dithiocarbamate (MDTC) to the chloro-functionalized silica matrix (SiCl), as a new adsorbent for adsorption of Pb(II), Cd(II), Cu(II) and Hg(II) from aqueous solution. The surface characterization was performed by FT-IR, XPS, SEM and elemental analysis indicating that the modification of the silica surface was successfully performed. The effects of media pH, adsorption time, initial metal ion concentration and adsorption temperature on adsorption capacity of the adsorbent had been investigated. Experimental data were exploited for kinetic and thermodynamic evaluations related to the adsorption processes. The characteristics of the adsorption process were evaluated by using the Langmuir, Freundlich and Dubinin-Radushkevich (D-R) adsorption isotherms and adsorption capacities were found to be 0.34 mmol g(-1), 0.36 mmol g(-1), 0.32 mmol g(-1) and 0.40 mmol g(-1) for Pb(II), Cd(II), Cu(II) and Hg(II), respectively. The adsorption mechanism of Hg(II) onto Si-DTC is quite different from that of Pb(II), Cd(II) or Cu(II) onto Si-DTC, which is demonstrated by the XPS and FT-IR results. PMID:21889843

Bai, Lan; Hu, Huiping; Fu, Weng; Wan, Jia; Cheng, Xiliang; Zhuge, Lei; Xiong, Lei; Chen, Qiyuan

2011-08-22

276

Biosorption of heavy metals and uranium from dilute solutions  

Energy Technology Data Exchange (ETDEWEB)

Eichhornia crassipes approaches being a scourge in many parts of the world, choking waterways and hindering transport upon them. At the same time it is known to readily abstract heavy metal ions from water and, thus, aids in the removal of heavy metals found in such waters. This paper considers the possibility of using specific parts of the plant as an inexpensive adsorbent for the removal of heavy metals from contaminated chemical and mining industry waste waters. In particular the root of the plant was found to be an excellent accumulator of heavy metal ions including uranium from solution. It is also suggested that dried roots of the plant might be placed in simple bags and used in a very low cost metal ion removal system.

Schneider, I.A.H. [Federal Univ. of Rio Grande do Sul (Brazil); Misra, M.; Smith, R.W. [Univ. of Nevada, Reno, NV (United States). Mackay School of Mines

1995-08-01

277

Biosorption of heavy metals and uranium from dilute solutions  

International Nuclear Information System (INIS)

Eichhornia crassipes approaches being a scourge in many parts of the world, choking waterways and hindering transport upon them. At the same time it is known to readily abstract heavy metal ions from water and, thus, aids in the removal of heavy metals found in such waters. This paper considers the possibility of using specific parts of the plant as an inexpensive adsorbent for the removal of heavy metals from contaminated chemical and mining industry waste waters. In particular the root of the plant was found to be an excellent accumulator of heavy metal ions including uranium from solution. It is also suggested that dried roots of the plant might be placed in simple bags and used in a very low cost metal ion removal system

1995-01-01

278

Inorganic particulates in removal of toxic heavy metal ions. Part 10. Removal behavior of aluminum hydroxide for Hg(II). A radiotracer study  

International Nuclear Information System (INIS)

The removal behavior of amorphous aluminum hydroxide for Hg(II) ions from aqueous solutions was investigated by employing a radiotracer technique at micro down to trace level concentrations. The batch type experiments were performed to obtain various physico-chemical parameters, viz., effect of sorptive concentration, temperature and pH. It was observed that the increase in sorptive concentration (from 1 x 10-8 to 1 x 10-2 mol x dm-3), temperature (from 303 to 333 K) and pH (from 3.4 to 10.3) apparently favored the uptake of Hg(II) by this solid. Similarly, the presence of anions (six fold) viz., oxalate, phosphate, glycine and EDTA also enhanced the uptake behavior of aluminum hydroxide for Hg(II). Whereas, the added cations viz., Na+, K+, Ba2+, Sr2+, Mg2+, Cd2+ and Fe3+ more or less suppressed the removal behavior of the adsorbent. Further, the adsorption process followed the classical Freundlich adsorption isotherm and deductions of various thermodynamic data revealed that the uptake of Hg(II) on aluminum hydroxide followed the ion-exchange type mechanism and thermodynamically it was found to be endothermic in nature. (author)

2007-01-01

279

Approaches for enhanced phytoextraction of heavy metals.  

UK PubMed Central (United Kingdom)

The contamination of the environment with toxic metals has become a worldwide problem. Metal toxicity affects crop yields, soil biomass and fertility. Soils polluted with heavy metals pose a serious health hazard to humans as well as plants and animals, and often requires soil remediation practices. Phytoextraction refers to the uptake of contaminants from soil or water by plant roots and their translocation to any harvestable plant part. Phytoextraction has the potential to remove contaminants and promote long-term cleanup of soil or wastewater. The success of phytoextraction as a potential environmental cleanup technology depends on factors like metal availability for uptake, as well as plants ability to absorb and accumulate metals in aerial parts. Efforts are ongoing to understand the genetics and biochemistry of metal uptake, transport and storage in hyperaccumulator plants so as to be able to develop transgenic plants with improved phytoremediation capability. Many plant species are being investigated to determine their usefulness for phytoextraction, especially high biomass crops. The present review aims to give an updated version of information available with respect to metal tolerance and accumulation mechanisms in plants, as well as on the environmental and genetic factors affecting heavy metal uptake. The genetic tools of classical breeding and genetic engineering have opened the door to creation of 'remediation' cultivars. An overview is presented on the possible strategies for developing novel genotypes with increased metal accumulation and tolerance to toxicity.

Bhargava A; Carmona FF; Bhargava M; Srivastava S

2012-08-01

280

Metal removal by natural glauconite  

Energy Technology Data Exchange (ETDEWEB)

Removal of cadmium, lead, zinc copper, and chromium by a natural clay mineral, glauconite, was studied using potentiometric titrations, continuous flow-through column reactors, and batch adsorption-desorption experiments and successfully modeled by surface complexation models (SCM). Potentiometric titration data were modeled using a simple single-site non-electrostatic model and a multi-site constant capacitance model. Important model parameters, such as surface site density and surface protonation-deprotonation constants, were also derived by fitting the titration data to SCMs. The metals compete effectively with protons for the surface sites, and bind strongly onto the surface of the mineral as shown by the significant shift in the potentiometric titration curves with or without these metals in glauconite suspension. Metal removal is primarily controlled by pH and can be modeled successfully by a single-site triple layer model along with the pH speciation of the metals. The successful application of SCMs in modeling titration and adsorption data of glauconite indicates that surface complexation is the primary mechanism in metal removal. Therefore, the theory of surface complexation can be used in predicting metal removal under different conditions such as pH, ionic strength, sorbent/sorbate ratio, and surface site density. The high metal removal capacities of glauconite are considered to be promising in treating some waste water.

Lu, W.; Smith, E.H. [Southern Methodist Univ., Dallas, TX (United States)

1995-12-31

 
 
 
 
281

Cell surface engineering of microorganisms towards adsorption of heavy metals.  

UK PubMed Central (United Kingdom)

Abstract Heavy metal contamination has become a worldwide environmental concern due to its toxicity, non-degradability and food-chain bioaccumulation. Conventional physical and chemical treatment methods for heavy metal removal have disadvantages such as cost-intensiveness, incomplete removal, secondary pollution and the lack of metal specificity. Microbial biomass-based biosorption is one of the approaches gaining increasing attention because it is effective, cheap, and environmental friendly and can work well at low concentrations. To enhance the adsorption properties of microbial cells to heavy metal ions, the cell surface display of various metal-binding proteins/peptides have been performed using a cell surface engineering approach. The surface engineering of Gram-negative bacteria, Gram-positive bacteria and yeast towards the adsorption of heavy metals are reviewed in this article. The problems and future perspectives of this technology are discussed.

Li PS; Tao HC

2013-08-01

282

Customizable Biopolymers for Heavy Metal Remediation  

International Nuclear Information System (INIS)

Nanoscale materials have been gaining increasing interest in the area of environmental remediation because of their unique physical, chemical and biological properties. One emerging area of research has been the development of novel materials with increased affinity, capacity, and selectivity for heavy metals because conventional technologies are often inadequate to reduce concentrations in wastewater to acceptable regulatory standards. Genetic and protein engineering have emerged as the latest tools for the construction of nanoscale materials that can be controlled precisely at the molecular level. With the advent of recombinant DNA techniques, it is now possible to create 'artificial' protein polymers with fundamentally new molecular organization. The most significant feature of these nanoscale biopolymers is that they are specifically pre-programmed within a synthetic gene template and can be controlled precisely in terms of sizes, compositions and functions at the molecular level. In this review, the use of specifically designed protein-based nano-biomaterials with both metal-binding and tunable properties for heavy metal removal is summarized. Several different strategies for the selective removal of heavy metals such as cadmium and mercury are highlighted

2005-01-01

283

Bioremediation of heavy metals using biosurfactants  

Directory of Open Access Journals (Sweden)

Full Text Available Industrial waste and sewage pollute more than 2/3 of India’s water resources. Stream pollution isa serious and growing problem in most developing countries where there is little waste water treatment.Increasing contamination of aquatic resources with pollution including heavy metals (like chromium, lead,cadmium, zinc, nickel etc.) endangers aquatic biota and declines water quality. Bioremediation is a processthat uses microorganisms or their enzymes to return the environment altered by contaminants to its originalcondition. Biological methods for the removal of heavy metals from industrial waste may provide anattractive alternative to the physico-chemical process; biosurfactants are one of the compounds that aid inalleviating the heavy metals. Microorganisms while trying to utilize substrates like hydrocarbon as carbonsource facilitate the diffusion into cell by producing a variety of substances called biosurfactants. Severalmicrobes such as Bacillus sp., Pseudomonas sp., Acinetiobacter sp. and Arthobacter sp. are reported toproduce biosufactants. Compared to synthetic compounds, biosurfactants offer the advantages of little or noenvironmental impact and the possibility of in situ production. Studies in recent past have demonstrated thesuccessful use of biosurfactants for facilitating the degradation of organic pollutants in soil and water. In thelight of above the present study is aimed to carry out the assessment of efficiency of biosurfactants(Rhamnolipid) producing microorganisms (Pseudomonas sp.) isolated from heavy metal contaminated site.

Jayabarath J.; Shyam Sundar S.; Arulmurugan R.; Giridhar R.

2009-01-01

284

COMPOSITION FOR HEAVY METAL DETOXIFICATION  

UK PubMed Central (United Kingdom)

PURPOSE: A detoxification composition using Smilax china extract or fermentation is provided to prevent cell death due to heavy metal. CONSTITUTION: A detoxification composition for heavy metal contains Smilax china extract a fermentation obtained by sealing mixture of Smilax china and ethanol solution and fermenting at room temperature(20-30 degrees Celsius) for 50-70 days and a fermentation by sealing mixture of Smilax china and ethanol solution and fermenting at room temperature(20-30 degrees Celsius) for 50-70 days and a step of maturing at low temperature(3-10 degrees Celsius) for 40-50 days.

KIM JIN HEE

285

Uso de biomassa seca de aguapé (Eichornia crassipes) visando à remoção de metais pesados de soluções contaminadas = Use of water hyacinth (Eichornia crassipes) dry biomass for removing heavy metals from contaminated solutions  

Directory of Open Access Journals (Sweden)

Full Text Available O presente trabalho avaliou a eficiência da biomassa seca de aguapé (Eichornia crassipes) na remoção dos metais pesados cádmio (Cd), chumbo (Pb), cromo (Cr), cobre (Cu), zinco (Zn) e níquel (Ni) de soluções preparadas com estes metais. O delineamento utilizado foi inteiramente casualizado, com cinco tratamentos (soluções com diferentes concentrações dos metais pesados) e quatro repetições. A biomassa seca permaneceu nas soluções dos tratamentos por um período de 48h, e nos intervalos de 1; 2; 3; 6; 12; 24; 36 e 48h após a instalação do experimento, coletaram-se alíquotas de cada tratamento,determinando-se a maior remoção de cada metal pesado pela biomassa seca do aguapé. Foi realizada digestão nitroperclórica na biomassa seca e determinação dos teores dos metais na biomassa e nas alíquotas por espectrometria de absorção atômica, modalidade chama. Paraos metais Cd, Pb, Cr, Cu e Zn ocorreu remoção significativa pela massa seca do aguapé nos diferentes tratamentos, enquanto para o Ni não foi encontrada diferença significativa. Dessa forma, conclui-se que a biomassa seca produzida, a partir do aguapé Eichornia crassipes, é um excelente material para a remoção, tanto em pequena como em grande escala, de corpos hídricos contaminados com metais pesados.The present work evaluated the efficiency of the dry biomass of water hyacinth (Eichornia crassipes) in the removal of heavy metalscadmium (Cd), lead (Pb), chromium (Cr), cupper (Cu), zinc (Zn) and nickel (Ni) from solutions prepared with these metals. The delineation used was entirely randomized, with five treatments (solutions with different concentrations of heavy metals) and fourrepetitions. The dry biomass remained in the treatment solutions for a period of 48h. In the intervals of 1; 2; 3; 6; 12; 24; 36 and 48h after experiment installation, samples were collected of each treatment, determining the greater removal for each heavy metal by water hyacinth dry biomass. Nitro-perchloric digestion was conducted in the dry biomass, and metal levels were determined in the dry biomass and in the samples by atomic absorption spectrometry, flame modality. The metals Cd, Pb, Cr, Cu e Zn were removed by waterhyacinth dry biomass in the different treatments, whereas for Ni removal did not occur. The water hyacinth Eichornia crassipes is an excellent material for removal, in small and larger scales, of water bodies contaminated with heavy metals.

Affonso Celso Gonçalves Junior; Claudemir Selzlein e Herbert Nacke

2009-01-01

286

Optimización del Proceso de Remoción de Metales Pesados de Agua Residual de la Industria Galvánica por Precipitación Química Optimization of the Removal Processs of Heavy Metals from Raw Water of Galvanic Industry by Chemical Precipitation  

Directory of Open Access Journals (Sweden)

Full Text Available Se han estudiado las condiciones óptimas requeridas para remover metales pesados del agua residual de una industria galvánica, que contiene cromo (435 mg/L), zinc (720 mg/L), hierro (168 mg/L) y níquel (24 mg/L). Se usó agua preparada en el laboratorio (agua sintética) y agua de la industria misma (agua cruda). El tratamiento se hizo mediante precipitación química, usando sosa para ajustar el pH y cloruro férrico como aditivo coagulante en un equipo de prueba de jarras. Las condiciones óptimas encontradas usando el agua sintética fueron: 7 minutos para el tiempo de floculación, 18 rpm para la velocidad de agitación y 11.8 mL para la dosis de coagulante. Para el agua cruda fueron: 9.5 minutos para el tiempo de floculación, 30 rpm para la velocidad de agitación y 5.2 mL para la dosis de coagulante. Las condiciones de tratamiento fueron diferentes para el agua residual cruda, ya que el agua residual cruda contiene otros contaminantes, los cuales sobrecargan la superficie coloidal, esto afecta el proceso de floculaciónThe aim of this research was to obtain the optimum conditions to remove heavy metals from wastewaters of the galvanic industry, which contain chromium (435 mg/L), zinc (720 mg/L), iron (168 mg/L) and nickel (24 mg/L). The treatment was made by chemical precipitation using caustic soda to set pH and ferric chloride like coagulant aid in jar test. The responses to optimize are: flocculation time, stirring speed and coagulant dose. The optimum conditions to remove heavy metals from synthetic wastewater was, flocculation time: 7 minutes, stirring speed: 18 rpm, coagulant dose: 11.8 mL and flocculation time: 9.5 minutes,stirring speed: 30 rpm, coagulant dose: 5.2 mL for raw wastewater. The treatment conditions were different for the raw wastewater because the raw wastewater contains other pollutants which over charge the colloidal surface and affects the flocculation processes

Eduardo Soto; Rosa del C Miranda; César A Sosa; José A Loredo

2006-01-01

287

A study of the removal of heavy metals from aqueous solutions by Moringa oleifera seeds and amine-based ligand 1,4-bis[N,N-bis(2-picoyl)amino]butane  

Energy Technology Data Exchange (ETDEWEB)

Highlights: Black-Right-Pointing-Pointer Materials are effective and selective in simultaneous removal of heavy metal ions. Black-Right-Pointing-Pointer Use of composite adsorbent of both materials may result in more effective material. Black-Right-Pointing-Pointer Seeds biomass has various functional groups involves in metal removal. Black-Right-Pointing-Pointer Attainment of sorption equilibrium is rapid for the seeds biomass. Black-Right-Pointing-Pointer Seeds biomass effectiveness is not affected over wide effective pH range. - Abstract: Uptake for lead, copper, cadmium, nickel and manganese from aqueous solution using the Moringa oleifera seeds biomass (MOSB) and amine-based ligand (ABL) was investigated. Experiments on two synthetic multi-solute systems revealed that MOSB performed well in the biosorption and followed the decreasing orders Pb(II) > Cu(II) > Cd(II) > Ni(II) > Mn(II) and Zn(II) > Cu(II) > Ni(II). The general trend of the heavy metal ions uptake by the amine-based ligand followed decreased in the order Mn > Cd > Cu > Ni > Pb, which is the reverse trend for what was observed for MOSB. Comparing the single- and multi-metal solutions, there was no clear effect in the biosorption capacity of MOSB suggesting the presence of sufficient active binding sites for all metal ions studied. The MOSB performance is also not affected by pH in the range 3.5-8.

Obuseng, Veronica; Nareetsile, Florence [Department of Chemistry, University of Botswana, Private Bag UB 00704, Gaborone (Botswana); Kwaambwa, Habauka M., E-mail: hmkwaambwa@yahoo.com [Department of Chemistry, University of Botswana, Private Bag UB 00704, Gaborone (Botswana)

2012-06-12

288

Biosorption of heavy metals on fungal biomass  

Energy Technology Data Exchange (ETDEWEB)

A method of using fungi in removing heavy metal from wastewater was discussed. Fungi for this purpose can be obtained inexpensively, and on a constant basis from industrial fermentation processes. The biosorption of lead, cadmium and nickel on fungal stock cultures, was investigated. In these experiments, the fungal stock used was Aspergillus niger and Rhizopus stolonfier. Alkali pre-treatment of the fungal biomass improved the metal biosorptive capacity in comparison to live cells. The effect of alkali treatment, however, varied,showing highest biosorptive capacity for lead and least for nickel. Results showed that metal biosorption of metallic ions increased with an increase in pH from 3.2 to 4.0. Equilibrium times of five hours were observed for the biosorption of lead and cadmium, while the equilibrium time for nickel was three hours. 10 refs., 3 tabs., 7 figs.

Kapoor, A.; Viraraghavan, T. [Regina Univ., SK (Canada). Faculty of Engineering

1996-09-01

289

Heavy metals in trees and energy crops - a literature review  

International Nuclear Information System (INIS)

This literature review deals with the use of energy crops for cleaning of soils from heavy metals. It also deals with the use of low accumulating energy crops to be used on strongly contaminated soils where a low uptake of heavy metals is preferred, for example on mining deposits. In addition to the efforts to reduce the sources for heavy metal contamination of soils (for example commercial fertilizers and atmospheric deposition) the uptake and removal of heavy metals from the soils by the use of energy crops have recently been discussed as a method for cleaning of soils. Species from the Salix family (willow) have a greater potential for accumulating heavy metals than cereals which makes them interesting for this purpose. The Salix family consists of species with a great genetic variation. This will probably make it possible to find or develop clones with different characteristics suitable for cleaning of contaminated soils as well as for plant covering of soils that are extremely contaminated by heavy metals. In the former case an accumulation of heavy metals in the harvested parts, the shoots, is preferred. In the later case clones that do not accumulate heavy metals and maybe also clones with only root accumulation are preferred. There are also Salix clones with a specific accumulation of heavy metals which makes it possible to clean soils from a toxic metal and at the same time avoid the risk for deficiency of essential metals, for example Zn. The greatest potential to clean soils by the use of energy crops, is when the contamination levels in the soils are low, the areas to clean are large and when the time needed for cleaning is of minor importance. The most suitable soils are those where the metal contamination is located in the top soil layer and where the heavy metal concentrations in the sub soil layer are still low. 58 refs, 8 tabs, 1 fig.

1995-01-01

290

Phytoremediation of Heavy Metals in Aqueous Solutions  

Directory of Open Access Journals (Sweden)

Full Text Available One of the major environmental problems is the pollution of water and soil by toxic heavy metals. This study investigated the phytoremediation potential of water hyacinth, for the removal of cadmium (Cd), lead (Pb) and zinc (Zn). Water hyacinths were cultured in bore-hole water, supplemented with 5mg/l of Zn and Pb and 1mg/l of Cd at pH 4.5, 6.8 and 8.5. The plants were separately harvested each week for six weeks. The results showed that removal of these metals from solution was fast especially in the first two weeks, after which it became gradual till saturation point was reached. The accumulation of Cd and Zn in leaves and roots increased with increase in pH. The highest accumulation was in the roots with metal concentration of 4870mg/kg, 4150mg/kg and 710mg/kg for Zn, Pb and Cd respectively at pH 8.5. The maximum values of bioconcentration factor (BCF) for Zn, Pb and Cd were 1674, 1531 and 1479 respectively, suggesting that water hyacinth was good accumulator of Zn, Pb and Cd, and could be used to treat industrial wastewater contaminated with heavy metals such as Zn, Pb and Cd.

Felix Aibuedefe AISIEN; Oluwole FALEYE; Eki Tina AISIEN

2010-01-01

291

Sand removal from heavy oil horizontal wells  

Energy Technology Data Exchange (ETDEWEB)

Oil production from heavy oil horizontal wells continues to be hindered by sand production and bridging resulting in total or partial shut-off of the wellbore. These bridges cannot be removed using circulation due to the low pressure of most heavy oil reservoirs. Removing these bridges using vertical or slanted well cleanout technology has proven to be difficult and costly, particularly if the production lateral is greater than 300-400 metres. With most laterals stretching beyond 1000 metres, producers and service companies have been in search of more effective alternatives. This challenge brought forth several new concepts in horizontal well cleanout technology involving artificial lift systems capable of continuous advancement into the lateral while producing high concentrations of sand. During the cleanout procedures, wellbore pressure is controlled thus avoiding high volumes of lost workover fluids. This presentation discusses these cleanout techniques as well as the positive and negative features of each.

Dedora, G. [GED Consulting Ltd., Cochrane, Alberta (Canada)

1995-12-31

292

Heavy Metal Stars  

Science.gov (United States)

La Silla Telescope Detects Lots of Lead in Three Distant Binaries Summary Very high abundances of the heavy element Lead have been discovered in three distant stars in the Milky Way Galaxy . This finding strongly supports the long-held view that roughly half of the stable elements heavier than Iron are produced in common stars during a phase towards the end of their life when they burn their Helium - the other half results from supernova explosions. All the Lead contained in each of the three stars weighs about as much as our Moon. The observations show that these "Lead stars" - all members of binary stellar systems - have been more enriched with Lead than with any other chemical element heavier than Iron. This new result is in excellent agreement with predictions by current stellar models about the build-up of heavy elements in stellar interiors. The new observations are reported by a team of Belgian and French astronomers [1] who used the Coude Echelle Spectrometer on the ESO 3.6-m telescope at the La Silla Observatory (Chile). PR Photo 26a/01 : A photo of HD 196944 , one of the "Lead stars". PR Photo 26b/01 : A CES spectrum of HD 196944 . The build-up of heavy elements Astronomers and physicists denote the build-up of heavier elements from lighter ones as " nucleosynthesis ". Only the very lightest elements (Hydrogen, Helium and Lithium [2]) were created at the time of the Big Bang and therefore present in the early universe. All the other heavier elements we now see around us were produced at a later time by nucleosynthesis inside stars. In those "element factories", nuclei of the lighter elements are smashed together whereby they become the nuclei of heavier ones - this process is known as nuclear fusion . In our Sun and similar stars, Hydrogen is being fused into Helium. At some stage, Helium is fused into Carbon, then Oxygen, etc. The fusion process requires positively charged nuclei to move very close to each other before they can unite. But with increasing atomic mass and hence, increasing positive charge of the nuclei, the electric repulsion between the nuclei becomes stronger and stronger. In fact, the fusion process only works up to a certain mass limit, corresponding to the element Iron [2]. All elements that are heavier than Iron cannot be produced via this path. But then, how were those heavy elements we now find on the Earth produced in the first place? From where comes the Zirconium in artificial diamonds, the Barium that colours fireworks, the Tungsten in the filaments in electric bulbs? Which process made the Lead in your car battery? Beyond iron The production of elements heavier than Iron takes place by adding neutrons to the atomic nuclei . These neutral particles do not feel any electrical repulsion from the charged nuclei. They can therefore easily approach them and thereby create heavier nuclei. This is indeed the way the heaviest chemical elements are built up. There are actually two different stellar environments where this process of "neutron capture" can happen. One place where this process occurs is inside very massive stars when they explode as supernovae . In such a dramatic event, the build-up proceeds very rapidly, via the so-called "r-process" ( "r" for rapid ). The AGB stars But not all heavy elements are created in such an explosive way. A second possibility follows a more "peaceful" road. It takes place in rather normal stars, when they burn their Helium towards the end of their lives. In the so-called "s-process" ( "s" for slow ), heavier elements are then produced by a rather gentle addition of neutral neutrons to atomic nuclei. In fact, roughly half of all the elements heavier than Iron are believed to be synthesized by this process during the late evolutionary phases of stars. This process takes place during a specific stage of stellar evolution, known as the "AGB" phase [3]. It occurs just before an old star expels its gaseous envelope into the surrounding interstellar s

2001-08-01

293

Heavy metal pumps in plants. 1997 annual progress report  

Energy Technology Data Exchange (ETDEWEB)

'Plants have been proposed as a bioremediation tool to help remove toxic heavy metals from contaminated land and water. However, little is known about how plants take up heavy metals from the soil and transport them to different parts of the plant. An important long term goal is to understand how heavy metals, such as copper and cadmium, are transported across the plasma membrane of plant cells. The proposed research is focused on a putative heavy metal uptake pump, AXA2p [Arabidopsis X (unknown heavy metal) ATPase, isoform 2 protein], identified in a model plant, Arabidopsis. AXA belongs to a super-family of ion-translocating P-type ATPases and is the first heavy metal pump cloned from plants. AXA2 is most similar to a subfamily of pumps recently identified in bacteria, yeast and humans which appear to pump heavy metals such as copper and cadmium. Three specific aims are proposed: (1) Determine the ion specificity of the AXA2 pump, (2) Determine how pumping activity is regulated, and (3) Determine if an increased uptake of specific heavy metals can be achieved by engineering a transgenic plant with a hyper-active pump. The hypothesis being tested is that AXA2 encodes a high affinity uptake pump for copper, with lower affinity for metals such as cadmium, zinc and nickel. Fundamental research on heavy metal transporters may eventually permit transgenic plants to be engineered with specific heavy metal uptake systems useful for bioremediation. The long term goal of the proposed research is to understand how heavy metals, such as copper and cadmium, are taken up from the soil and translocated throughout the plant. The focus is on a putative heavy metal pump, AXA2p [Arabidopsis X (unknown heavy metal) ATPase, isoform 2 protein], identified in a model plant, Arabidopsis. AXA2 belongs to a large family of ion-translocating P-type ATPases. AXA2p is the first heavy metal pump cloned from plants and is most similar to a subfamily of heavy metal pumps recently identified in bacteria, yeast and humans.'

Harper, J.F.

1997-01-01

294

Transmission of toxic heavy metals to wheat grinding fractions  

Energy Technology Data Exchange (ETDEWEB)

In this examination, highly contaminated wheat which on account of a sewer slude fertilization showed high contents of cadmium (1 mg/kg), nickel (2,5 mg/kg) and zinc (75 mg/kg) was subjected to two different hulling procedures (laboratory pearler and pressing screw) to determine the reduction of the heavy metals. About 5-10% of the heavy metals cadmium and zinc could be removed by the hulling procedures with an abrasion of 4-6%, nickel was reduced by about 15%. The lead contamination could be removed by about 50%. The best reduction of the heavy metals was achieved by the grinding procedure. In the low-ash flours of the types 405 and 550, the contents of the heavy metals were reduced by more than 50%. In the flours of the types 812 and 1050 being higher on ash, the heavy metal contents were reduced by about 35-40% as compared to the initial product. In the high-ash low-grade flours, the heavy metal contents rose already to twice the concentration as to that in the initial wheat. In the bran fractions the heavy metal contents finally rise to two to five times the amount as in the initial wheat. The findings well conform to results from earlier investigations determined in normally contaminated wheat and wheat grinding fractions.

Brueggemann, J.; Ocker und Muehlening, H.D.; Zwingelberg, H.

1983-08-25

295

Bioremediation of heavy metals in liquid media through fungi isolated from contaminated sources.  

UK PubMed Central (United Kingdom)

Wastewater particularly from electroplating, paint, leather, metal and tanning industries contain enormous amount of heavy metals. Microorganisms including fungi have been reported to exclude heavy metals from wastewater through bioaccumulation and biosorption at low cost and in eco-friendly way. An attempt was, therefore, made to isolate fungi from sites contaminated with heavy metals for higher tolerance and removal of heavy metals from wastewater. Seventy-six fungal isolates tolerant to heavy metals like Pb, Cd, Cr and Ni were isolated from sewage, sludge and industrial effluents containing heavy metals. Four fungi (Phanerochaete chrysosporium, Aspegillus awamori, Aspergillus flavus, Trichoderma viride) also were included in this study. The majority of the fungal isolates were able to tolerate up to 400 ppm concentration of Pb, Cd, Cr and Ni. The most heavy metal tolerant fungi were studied for removal of heavy metals from liquid media at 50 ppm concentration. Results indicated removal of substantial amount of heavy metals by some of the fungi. With respect to Pb, Cd, Cr and Ni, maximum uptake of 59.67, 16.25, 0.55, and 0.55 mg/g was observed by fungi Pb3 (Aspergillus terreus), Trichoderma viride, Cr8 (Trichoderma longibrachiatum), and isolate Ni27 (A. niger) respectively. This indicated the potential of these fungi as biosorbent for removal of heavy metals from wastewater and industrial effluents containing higher concentration of heavy metals.

Joshi PK; Swarup A; Maheshwari S; Kumar R; Singh N

2011-10-01

296

Bioremediation of heavy metals in liquid media through fungi isolated from contaminated sources.  

Science.gov (United States)

Wastewater particularly from electroplating, paint, leather, metal and tanning industries contain enormous amount of heavy metals. Microorganisms including fungi have been reported to exclude heavy metals from wastewater through bioaccumulation and biosorption at low cost and in eco-friendly way. An attempt was, therefore, made to isolate fungi from sites contaminated with heavy metals for higher tolerance and removal of heavy metals from wastewater. Seventy-six fungal isolates tolerant to heavy metals like Pb, Cd, Cr and Ni were isolated from sewage, sludge and industrial effluents containing heavy metals. Four fungi (Phanerochaete chrysosporium, Aspegillus awamori, Aspergillus flavus, Trichoderma viride) also were included in this study. The majority of the fungal isolates were able to tolerate up to 400 ppm concentration of Pb, Cd, Cr and Ni. The most heavy metal tolerant fungi were studied for removal of heavy metals from liquid media at 50 ppm concentration. Results indicated removal of substantial amount of heavy metals by some of the fungi. With respect to Pb, Cd, Cr and Ni, maximum uptake of 59.67, 16.25, 0.55, and 0.55 mg/g was observed by fungi Pb3 (Aspergillus terreus), Trichoderma viride, Cr8 (Trichoderma longibrachiatum), and isolate Ni27 (A. niger) respectively. This indicated the potential of these fungi as biosorbent for removal of heavy metals from wastewater and industrial effluents containing higher concentration of heavy metals. PMID:23024411

Joshi, P K; Swarup, Anand; Maheshwari, Sonu; Kumar, Raman; Singh, Namita

2011-01-25

297

Micellar-enhanced ultrafiltration of heavy metals using lecithin  

Energy Technology Data Exchange (ETDEWEB)

Conventional treatment methods for removal of heavy metals from metal finishing operations are usually energy-intensive and costly. Micellar-enhanced ultrafiltration (MEUF) with synthetic surfactants is a recently developed technique which can remove heavy metals and other small molecular weight ions from wastestreams at relatively lower costs and without a phase change. Lecithin, a natural, inexpensive, nontoxic, and biodegradable surfactant exhibits emulsifying characteristics which can be used in a MEUF. The binding of various lecithins to cadmium, copper, lead, nickel, and zinc - in a mixture and individually - was studied using a continuous diafiltration method. This technique uses small volumes of toxic waters and produces an entire isotherm with just one experiment. In the presence of all five heavy metals, the lecithin in this study showed the following affinity: Cu > Cd [approximately] Zn > Ni. In experiments when only one metal was present, lecithin exhibited the following affinity: Ni > Cu [approximately] Zn > Cd. Lead was not bound significantly in either scenario.

Ahmadi, S.; Tseng, L.K.; Batchelor, B.; Koseoglu, S.S. (Texas A M Univ., College Station, TX (United States))

1994-12-01

298

Monitoring heavy metal pollutants in Tai Hu  

Energy Technology Data Exchange (ETDEWEB)

In 1980-81, specimens of 66 species of macroscopic hydrophytes were collected from Tai Hu to determine their contents of arsenic, chromium, copper, lead, zinc, and molybdenum by techniques of oscillo-polarography and atomic absorption spectrophotometry. Relationships between the heavy metal contents of plants and those of the water and sediments of different areas of the lake, and the ash contents of different species and parts of plants are discussed. Heavy metal contents of eastern stream estuaries are found to be higher than the western part of the lake to demonstrate the importance of controlling the disposal of wastes from factories located above the lake region. The high rate of utilization (60 percent) of Tai Hu hydrophytes as fertilizer, feed, and industrial raw material obviously helps to remove heavy metals from the lake and thus improve the lacustrine environment. The water is found to be generally of good quality at present and only about 1 percent of the lake may be said to be polluted.

Dai Quanyu

1983-09-01

299

Preparation and characterization of multi-walled carbon nanotubes/chitosan nanocomposite and its application for the removal of heavy metals from aqueous solution  

International Nuclear Information System (INIS)

[en] Research highlights: ? Nanocomposite made of multi-walled carbon nanotubes and chitosan was prepared and characterized. ? The characterization confirmed the homogenous and well distribution of the MWCNTs within the chitosan matrix. ? MWCNTs/chitosan nanocomposite was used for the removal of copper, zinc, cadmium and nickel ions from aqueous solution. ? The results showed that nanocomposite could remove successfully most of the metal ions from solution with high efficiency. - Abstract: Multi-walled carbon nanotubes (MWCNTs) were modified with chitosan, and a homogenous nanocomposite was obtained. The morphological properties of the MWCNTs/chitosan nanocomposite were studied with scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), and thermal gravimetric analysis (TGA). The morphological results indicate the successful modification and the formation of MWCNTs/chitosan nanocomposites. The MWCNTs/chitosan nanocomposite was packed inside a glass column and used for the removal of copper, zinc, cadmium, and nickel ions from aqueous solution. The MWCNTs/chitosan nanocomposite showed a great efficiency for the removal of the target metal ions from the aqueous solution. The results suggested that this novel MWCNTs/chitosan nanocomposite could be used for different environmental applications.

2011-02-03

300

Preparation and characterization of multi-walled carbon nanotubes/chitosan nanocomposite and its application for the removal of heavy metals from aqueous solution  

Energy Technology Data Exchange (ETDEWEB)

Research highlights: > Nanocomposite made of multi-walled carbon nanotubes and chitosan was prepared and characterized. > The characterization confirmed the homogenous and well distribution of the MWCNTs within the chitosan matrix. > MWCNTs/chitosan nanocomposite was used for the removal of copper, zinc, cadmium and nickel ions from aqueous solution. > The results showed that nanocomposite could remove successfully most of the metal ions from solution with high efficiency. - Abstract: Multi-walled carbon nanotubes (MWCNTs) were modified with chitosan, and a homogenous nanocomposite was obtained. The morphological properties of the MWCNTs/chitosan nanocomposite were studied with scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), and thermal gravimetric analysis (TGA). The morphological results indicate the successful modification and the formation of MWCNTs/chitosan nanocomposites. The MWCNTs/chitosan nanocomposite was packed inside a glass column and used for the removal of copper, zinc, cadmium, and nickel ions from aqueous solution. The MWCNTs/chitosan nanocomposite showed a great efficiency for the removal of the target metal ions from the aqueous solution. The results suggested that this novel MWCNTs/chitosan nanocomposite could be used for different environmental applications.

Salam, Mohamed Abdel, E-mail: masalam16@hotmail.com [Chemistry Department, Faculty of Science, King Abdulaziz University, P.O. Box 80200, Jeddah 21589 (Saudi Arabia); Makki, Mohamad S.I.; Abdelaal, Magdy Y.A. [Chemistry Department, Faculty of Science, King Abdulaziz University, P.O. Box 80200, Jeddah 21589 (Saudi Arabia)

2011-02-03

 
 
 
 
301

Effect of heavy metals on bacterial transport  

Science.gov (United States)

Adsorption of metals onto bacteria and soil takes place as stormwater runoff infiltrates into the subsurface. Changes in both bacterial surfaces and soil elemental content have been observed, and may alter the attachment of bacteria to soil surfaces. In this study, scanning electron microscopy (SEM) and Energy Dispersive X-ray Spectrometry (EDS) analyses were performed on soil samples equilibrated with synthetic stormwater amended with copper, lead and zinc. The results demonstrate the presence of copper and zinc on soil surfaces. To investigate bacterial attachment behavior, sets of batch sorption experiments were conducted on Escherichia Coli (E. coli) under different chemical conditions by varying solution compositions (nutrient solution vs synthetic stormwater). The adsorption data is best described using theoretical linear isotherms. The equilibrium coefficient (Kd) of E. coli is higher in synthetic stormwater than in nutrient solution without heavy metals. The adsorption of heavy metals onto bacterial surfaces significantly decreases their negative surface charge as determined via zeta potential measurements (-17.0±5.96mv for E. coli equilibrated with synthetic stormwater vs -21.6±5.45mv for E. coli equilibrated with nutrient solution), indicating that bacterial attachment may increase due to the attachment of metals onto bacterial surfaces and their subsequent change in surface charge. The attachment efficiency (?) of bacteria was also calculated and compared for both solution chemistries. Bacterial attachment efficiency (?) in synthetic stormwater is 0.997, which is twice as high as that in nutrient solution(? 0.465). The ratio of bacterial diameter : collector diameter suggests minimal soil straining during bacterial transport. Results suggest that the presence of metals in synthetic stormwater leads to an increase in bacterial attachment to soil surfaces. In terms of designing stormwater infiltration basins, the presence of heavy metals seems to reduce the soil depth required to achieve certain levels of bacterial removal. This study demonstrates the effect of chemical constituents in stormwater runoff on bacterial transport in the subsurface.

Zhang, H.; Olson, M. S.

2010-12-01

302

Bacterial sorption of heavy metals  

Energy Technology Data Exchange (ETDEWEB)

Four bacteria, Bacillus cereus, B. subtilis, Escherichia coli, and Pseudomonas aeruginosa, were examined for the ability to remove Ag{sup +}, Cd{sup 2+}, Cu{sup 2+}, and La{sup 3+} from solution by batch equilibration methods. Cd and Cu sorption over the concentration range 0.001 to 1 mM was described by Freundlich isotherms. At 1 mM concentrations of both Cd{sup 2+} and Cu{sup 2+}, P. aeruginosa and B. cereus were the most and least efficient at metal removal, respectively. Freundlich K constants indicated that E. coli was most efficient at Cd{sup 2+} removal and B. subtilis removed the most Cu{sup 2+}. Removal of Ag{sup +} from solution by bacteria was very efficient; an average of 89% of the total Ag{sup +} was removed from the 1 mM solution, whereas only 12, 29, and 27% of the total Cd{sup 2+}, Cu{sup 2+}, and La{sup 3+}, respectively, were sorbed from 1 mM solutions. Electron microscopy indicated that La{sup 3+} accumulated at the cell surface as needlelike, crystalline precipitates. Silver precipitated as discrete colloidal aggregates at the cell surface and occasionally in the cytoplasma. The results indicate that bacterial cells are capable of binding large quantities of different metals.

Mullen, M.D.; Wolf, D.C.; Ferris, F.G.; Beveridge, T.J.; Flemming, C.A.

1989-01-01

303

Adsorption of heavy metal toxic waste from dilute solutions  

Energy Technology Data Exchange (ETDEWEB)

Low concentrations of toxic heavy metals generally encountered in wastewater treatment exclude, for economical reasons, the use of traditional removal methods such as chemical precipitation, ion exchange, filtration, membrane technology, etc. The economical feasibility of recovering heavy metals can be extended by using relatively inexpensive yet efficient natural biopolymers. Pursuant to their goal of using these biopolymers in decontaminating natural waters, the authors have measured thermodynamic and kinetic parameters for combinations of metals over a series of temperatures. Copper, lead and zinc divalent metal ions were investigated, as were three different types of calcium alginate biopolymer gel beads. Water-jacketed batch reactors were used in these studies.

Lewandowski, Z.; Roe, F.; Twedt, M.; Nguyen, D.; Surapanini, P. [Montana State Univ., Bozeman, MT (United States). Center for Biofilm Engineering

1994-12-31

304

Dissymmetrical tunnelling in heavy fermion metals  

CERN Document Server

A tunnelling conductivity between a heavy fermion metal and a simple metallic point is considered. We show that at low temperatures this conductivity can be noticeably dissymmetrical with respect to the change of voltage bias. The dissymmetry can be observed in experiments on the heavy fermion metals whose electronic system has undergone the fermion condensation quantum phase transition.

Shaginyan, V R

2005-01-01

305

Poisoning of domestic animals with heavy metals  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The term heavy metal refers to a metal that has a relatively high density and is toxic for animal and human organism at low concentrations. Heavy metals are natural components of the Earth's crust. They cannot be degraded or destroyed. To a small extent they enter animal organism via food, drinking ...

Velev Romel; Krleska-Veleva Nataša; ?upi? Vitomir

306

Heavy Metal Contamination in Canned Tuna Fish  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Heavy metal contamination of food products, especially seafood is a major concern because of the bioaccumulation and biomagnification of metal contaminants. Their detection in fish is an indicator of marine pollution. In this study heavy metal concentrations were measured in a sample of commercially...

F Emami-Khansari; M Abdollahi; M Ghazi-Khansari

307

Industrial hygiene of selected heavy metals  

Energy Technology Data Exchange (ETDEWEB)

The industrial hygiene of heavy metals consists of recognition, evaluation, and control of exposures in the occupational environment. Several of these metals have been in use since ancient times. Reports of health effects and poisonings from overexposures also have a long history. This report discusses the industrial hygiene of the heavy metals, lead, cadmium, mercury, and manganese.

Woodring, J.L.

1993-08-01

308

Removal of metals by sorghum plants from contaminated land.  

Science.gov (United States)

The growth of high biomass crops facilitated by optimal of agronomic practices has been considered as an alternative to phytoremediation of soils contaminated by heavy metals. A field trial was carried out to evaluate the phytoextraction efficiency of heavy metals by three varieties of sweet sorghum (Sorghum biocolor L.), a high biomass energy plant. Ethylene diamine tetraacetate (EDTA), ammonium nitrate (NH4NO3) and ammonium sulphate ((NH4)2SO4) were tested for their abilities to enhance the removal of heavy metals Pb, Cd, Zn, and Cu by sweet sorghum from a contaminated agricultural soil. Sorghum plants always achieved the greatest removal of Pb by leaves and the greatest removal of Cd, Zn and Cu by stems. There was no significant difference among the Keller, Rio and Mray varieties of sweet sorghums in accumulating heavy metals. EDTA treatment was more efficient than ammonium nitrate and ammonium sulphate in promoting Pb accumulation in sweet sorghum from the contaminated agricultural soil. The application of ammonium nitrate and ammonium sulphate increased the accumulation of both Zn and Cd in roots of sorghum plants. Results from this study suggest that cropping of sorghum plants facilitated by agronomic practices may be a sustainable technique for partial decontamination of heavy metal contaminated soils. PMID:19999999

Zhuang, Ping; Shu, Wensheng; Li, Zhian; Liao, Bin; Li, Jintian; Shao, Jingsong

2009-01-01

309

Removal of metals by sorghum plants from contaminated land.  

UK PubMed Central (United Kingdom)

The growth of high biomass crops facilitated by optimal of agronomic practices has been considered as an alternative to phytoremediation of soils contaminated by heavy metals. A field trial was carried out to evaluate the phytoextraction efficiency of heavy metals by three varieties of sweet sorghum (Sorghum biocolor L.), a high biomass energy plant. Ethylene diamine tetraacetate (EDTA), ammonium nitrate (NH4NO3) and ammonium sulphate ((NH4)2SO4) were tested for their abilities to enhance the removal of heavy metals Pb, Cd, Zn, and Cu by sweet sorghum from a contaminated agricultural soil. Sorghum plants always achieved the greatest removal of Pb by leaves and the greatest removal of Cd, Zn and Cu by stems. There was no significant difference among the Keller, Rio and Mray varieties of sweet sorghums in accumulating heavy metals. EDTA treatment was more efficient than ammonium nitrate and ammonium sulphate in promoting Pb accumulation in sweet sorghum from the contaminated agricultural soil. The application of ammonium nitrate and ammonium sulphate increased the accumulation of both Zn and Cd in roots of sorghum plants. Results from this study suggest that cropping of sorghum plants facilitated by agronomic practices may be a sustainable technique for partial decontamination of heavy metal contaminated soils.

Zhuang P; Shu W; Li Z; Liao B; Li J; Shao J

2009-01-01

310

Poisoning of domestic animals with heavy metals  

Directory of Open Access Journals (Sweden)

Full Text Available The term heavy metal refers to a metal that has a relatively high density and is toxic for animal and human organism at low concentrations. Heavy metals are natural components of the Earth's crust. They cannot be degraded or destroyed. To a small extent they enter animal organism via food, drinking water and air. Some heavy metals (e.g cooper, iron, chromium, zinc) are essential in very low concentrations for the survival of all forms of life. These are described as essential trace elements. However, when they are present in greater quantities, like the heavy metals lead, cadmium and mercury which are already toxic in very low concentrations, they can cause metabolic anomalies or poisoning. Heavy metal poisoning of domestic animals could result, for instance, from drinking-water contamination, high ambient air concentrations near emission sources, or intake via the food chain. Heavy metals are dangerous because they tend to bioaccumulate in a biological organism over time. Manifestation of toxicity of individual heavy metals varies considerably, depending on dose and time of exposure, species, gender and environmental and nutritional factors. Large differences exist between the effects of a single exposure to a high concentration, and chronic exposures to lower doses. The aim of this work is to present the source of poisoning and toxicity of some heavy metals (lead, mercury, cadmium, thallium, arsenic), as well as new data about effects of those heavy metals on the health of domestic animals. .

Velev Romel; Krleska-Veleva Nataša; ?upi? Vitomir

2009-01-01

311

The Effect of Generated Chlorine Gas on Electroremediation of Heavy Metals from Offshore Muds  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The removal efficiency of heavy metals from offshore muds is enhanced in the presence of generated chlorine gas (Cl2). The tests showed a high removal efficiency of heavy metals at the anode end of cores after 24 hours of EK application. In the initial tests, high electrokinet...

Sanghee Shin; George V. Chilingar; Muhammad Haroun; Bisweswar Ghosh; Najmedin Meshkati; Sibel Pamukcu; J. Kenneth Wittle

312

Biosorption of heavy metals under anaerobic conditions. Final report  

International Nuclear Information System (INIS)

The precipitation of heavy metals as hydroxides is the standard technique for the decontamination of waste water streams polluted by these elements. On the other side, progress in research has been made concerning the biosorption onto dead biomass and bioprecipitation supported by physiologically active bacteria. As the aim of this study, a flexible strategy has been envisaged cleaning a waste water with definite heavy metal load underlying the process mentioned above. Suitable bacteria were enriched and the process was tested in a technical plant. As result, a very high efficiency of heavy metal elimination has been found. The field of application covered by the acquired process is identical with the whole range of the waste water streams polluted by heavy metals. In addition, a second stage may be necessary if there are any further contaminants to be removed. (orig.).

1996-01-01

313

Adsorption of heavy metals on rhizosphere soil  

Energy Technology Data Exchange (ETDEWEB)

Ion exchange, surface adsorption/desorption, complexation by organic materials, and precipitation/dissolution of discreet solid phases are typical mechanisms that control heavy metals in solution. Understanding the mechanism that is responsible for a given metal is critical to prediction of leaching behavior. Plants can affect mobility of heavy metals by releasing organic compounds into the rhizosphere. Some of the organics released by plant roots (and microorganisms) are strong complexing agents for metals and can potentially increase metal mobility. Sorption and desorption reactions (kinetics and isotherms) of a variety of heavy metals will be determined for diffusion controlled and ion exchange reactions. Organic compounds that could impact metal transport, mine tailings, and soil will be equilibrated for approximately 18 hours in batch studies. The solution phase will be separated and concentrations of target metals measured. This research will quantify heavy metal adsorption/desorption characteristics of soil influenced by plant roots.

He, Y.; Burckhard, S.; Schwab, A.P.; Banks, M.K. [Kansas State Univ., Manhattan, KS (United States)

1994-12-31

314

Induction of in vitro roots cultures of Thypha latifolia and Scirpus americanus and study of their capacity to remove heavy metals  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english We have established the conditions to obtain in vitro root cultures of Thypha latifolia and Scirpus americanus and have investigated their capacity to remove Pb(II), Mn(II) and Cr(III) from the culture medium. The best conditions for the in vitro culture growth were: an inoculum of 0.2 g of T. latifolia roots and 0.05 g of S. americanus roots (fresh weight), Murashige-Skoog medium and 2 mg L-1of indolacetic acid. The T. latifolia and S. americanus root cultures were culti (more) vated onto media containing Cr (15 µg L-1), Pb (60 µg L-1) or Mn (1.8 mg L-1). Both species were able to remove Pb and Cr near to 100% and 71-100% of Mn from the medium solution during the 6-8 days of experimentation. According to metal concentrations removed from the medium containing the growing root mass, the in vitro root culture of S. americanus can be considered as an accumulator for Pb (157.73 µg g-1), Cr (55.6 µg g-1) and Mn (5000 µg g-1).

Santos-Díaz, María del Socorro; Barrón-Cruz, María del Carmen; Alfaro-De la Torre, María Catalina

2007-07-01

315

[Heavy metal content of cereals and potatoes  

UK PubMed Central (United Kingdom)

By means of atomic absorption spectrometry, the authors determined the cadmium, zinc, copper and manganese contents in potatoes and cereals from three territories differently burdened by heavy-metal immissions (rural region, overcrowded urban region, region with non-ferrous metal industry). Of these elements, cadmium was most enriched, followed (by a wide margin) by zinc and copper, whereas the manganese level was slightly higher in the burdened region II (compared to the burdened region I) and somewhat lower in the burdened region III. Compared to normal values (0.035--0.080 p.p.m.), i. e., values found in non-burdened regions, the cadmium contents were some 2- to 6-fold higher in air-dry samples of wheat, barley and rye from the burdened regions, some 30-fold higher in oats, and some 3- to 4-fold higher in potatoes (normal values, on a dry-weight basis, (0.140 p.p.m.). As to cereals, the zinc levels were, at the most, some 2-fold higher than the normal values (29--34 p.p.m.), the copper contents were, at the most, some 1.5-fold higher than the normal values (4.1 bis 4.8 p.p.m.), whereas the manganese levels (normal values, 14--30 p.p.m.) were less by half. In potatoes, the zinc contents were but slightly higher than the normal values (18.5 p.p.m., on a dry-weight basis), the copper levels (4.6 p.p.m., on a dry-weight basis) were some 2-fold higher, and the manganese contents (7.2 p.p.m., on a dry-weight basis) were somewhat reduced. On an average 26% (region with non-ferrous metal industry) or 13% (normal region) of the heavy metals are removable from potatoes by washing. On the basis of the results obtained and of data from the literature, an estimate is calculated for the expected values in territories differently burdened by heavy-metal immissions. Finally, targeted suggestions are given for preventing or impeding the entrance of heavy metals into the biocycle.

Auermann E; Dässler HG; Jacobi J; Cumbrowski J; Meckel U

1980-01-01

316

Heavy metals in Antarctic organisms  

Energy Technology Data Exchange (ETDEWEB)

To evaluate levels of essential (zinc and copper) and non-essential (mercury and cadmium) heavy metals, 34 species of organisms from different areas close to the Antarctic Peninsula were analysed. These included algae, filter-feeders, omnivorous invertebrates and vertebrates. Mercury was not detected, while cadmium was found in the majority of organisms analysed (detection limit was 0.05 ppm for both metals). The highest cadmium concentration was observed in the starfish Odontaster validus. Anthozoans, sipunculids and nudibranchs showed maximum levels of zinc, while the highest copper level was found in the gastropod Trophon brevispira. Mercury and cadmium levels in fishes were below the detection limit. Concentrations of essential and non-essential metals in birds were highest in liver followed by muscle and eggs. Cadmium and mercury levels in muscle of southern elephant seals were above the detection limit, whereas in Antarctic fur seals they were below it. The objective of the study was to gather baseline information for metals in Antarctic Ocean biota that may be needed to detect, measure and monitor future environmental changes. 46 refs., 7 figs., 8 tabs.

Moreno, J.E.A. de; Moreno, V.J. [Universidad Nacional de Mar del Plata (Argentina); Gerpe, M.S.; Vodopivez, C. [Instituto Antartico Argentino, Buenos Aires (Argentina)

1997-02-01

317

Mosses accumulate heavy metals from the substrata of coal ash  

Directory of Open Access Journals (Sweden)

Full Text Available Plants that are able to accumulate and tolerate extraordinarily high concentrations of heavy metals (hyperaccumulators) can be used for phytoremediation (removal of contaminants from soils) or phytomining (growing a crop of plants to harvest the metals). Two moss species, Bryum capillare Hedw. and Ceratodon purpureus Hedw., were tested as potential phytoremedies under in vivo conditions on a coal ash disposal site in the surroundings of Obrenovac (NW Serbia). The content of various heavy metals (iron, manganese zinc, lead, nickel, cadmium, and copper) in the mosses and substrata were investigated over a period of three years. Iron and zinc were found to have the highest concentration in the mosses.

Vukojevi? Vanja; Sabovljevi? Marko; Jovanovi? S.

2005-01-01

318

Sorption of heavy metal ions on new metal-ligand complexes chemically derived from Lycopodium clavatum  

Energy Technology Data Exchange (ETDEWEB)

Sorption of heavy metal ions from aqueous solution has been investigated as a function of pH using a novel exchanger system whereby Lycopodium clavatum is functionalized with carboxylate and glyoxime metal-ligand complexes. The new ligand exchangers were prepared using a reaction of diaminosporopollenin with various metal-ligand complexes of glyoxime and monocarboxylic acid. The sorptive behavior of these metal-ligand exchangers and the possibilities to remove and to recover selectively heavy metal cations using these systems are discussed on the basis of their chemical natures and their complexing properties.

Pehlivan, E.; Ersoz, M.; Yildiz, S. [Univ. of Selcuk, Konya (Turkey); Duncan, H.J. [Univ. of Glasgow, Scotland (United Kingdom)

1994-08-01

319

Heavy metal uptake by fast growing willow species  

International Nuclear Information System (INIS)

Bioremediation is a general term used to describe the use of biological systems for renovating contaminated soil. The technique can be divided into two categories: the use of microbiological processes, and the use of vegetation, to immobilize, transform or remove contaminants from the soil. It has been suggested that the rapid biomass accumulation of Salix species grown intensively as in short-rotation forestry systems, may be used to remove heavy metal contamination from soil. Many potentially toxic heavy metals are also essential plant nutrients, hence the mechanisms exist for the absorption by plants of these and similar ions and their translocation through the plant structure. A limited number of deciduous species have been found to translocate metals to the leaves immediately before senescence, however, the principal site of metal accumulation in higher plants is the roots. A small number of species endemic to metalliferous soils are capable of accumulating unusually high concentrations of potentially toxic metals in their above ground biomass. These have been termed hyperaccumulators. This paper reports on the level and location of heavy metal accumulation by four varieties of Salix growing in soils with elevated levels of heavy metals. A trial was established in 1991 on land with a long history of sewage sludge application. Further applications have been made each year and the first harvest taken in January 1994. Significant differences have been found between the take-up of individual metals, between willow varieties and across differing sludge applications. 7 refs, 1 fig, 6 tabs.

1994-01-01

320

Hazards of heavy metal contamination.  

UK PubMed Central (United Kingdom)

The main threats to human health from heavy metals are associated with exposure to lead, cadmium, mercury and arsenic. These metals have been extensively studied and their effects on human health regularly reviewed by international bodies such as the WHO. Heavy metals have been used by humans for thousands of years. Although several adverse health effects of heavy metals have been known for a long time, exposure to heavy metals continues, and is even increasing in some parts of the world, in particular in less developed countries, though emissions have declined in most developed countries over the last 100 years. Cadmium compounds are currently mainly used in re-chargeable nickel-cadmium batteries. Cadmium emissions have increased dramatically during the 20th century, one reason being that cadmium-containing products are rarely re-cycled, but often dumped together with household waste. Cigarette smoking is a major source of cadmium exposure. In non-smokers, food is the most important source of cadmium exposure. Recent data indicate that adverse health effects of cadmium exposure may occur at lower exposure levels than previously anticipated, primarily in the form of kidney damage but possibly also bone effects and fractures. Many individuals in Europe already exceed these exposure levels and the margin is very narrow for large groups. Therefore, measures should be taken to reduce cadmium exposure in the general population in order to minimize the risk of adverse health effects. The general population is primarily exposed to mercury via food, fish being a major source of methyl mercury exposure, and dental amalgam. The general population does not face a significant health risk from methyl mercury, although certain groups with high fish consumption may attain blood levels associated with a low risk of neurological damage to adults. Since there is a risk to the fetus in particular, pregnant women should avoid a high intake of certain fish, such as shark, swordfish and tuna; fish (such as pike, walleye and bass) taken from polluted fresh waters should especially be avoided. There has been a debate on the safety of dental amalgams and claims have been made that mercury from amalgam may cause a variety of diseases. However, there are no studies so far that have been able to show any associations between amalgam fillings and ill health. The general population is exposed to lead from air and food in roughly equal proportions. During the last century, lead emissions to ambient air have caused considerable pollution, mainly due to lead emissions from petrol. Children are particularly susceptible to lead exposure due to high gastrointestinal uptake and the permeable blood-brain barrier. Blood levels in children should be reduced below the levels so far considered acceptable, recent data indicating that there may be neurotoxic effects of lead at lower levels of exposure than previously anticipated. Although lead in petrol has dramatically decreased over the last decades, thereby reducing environmental exposure, phasing out any remaining uses of lead additives in motor fuels should be encouraged. The use of lead-based paints should be abandoned, and lead should not be used in food containers. In particular, the public should be aware of glazed food containers, which may leach lead into food. Exposure to arsenic is mainly via intake of food and drinking water, food being the most important source in most populations. Long-term exposure to arsenic in drinking-water is mainly related to increased risks of skin cancer, but also some other cancers, as well as other skin lesions such as hyperkeratosis and pigmentation changes. Occupational exposure to arsenic, primarily by inhalation, is causally associated with lung cancer. Clear exposure-response relationships and high risks have been observed.

Järup L

2003-01-01

 
 
 
 
321

Heavy Metal Concentrations in Predator Fish  

Directory of Open Access Journals (Sweden)

Full Text Available Waters can be polluted by heavy metals which are accumulated and concentrated by fish therefore they show the degree of environmental pollution. The aim of this study was to determine concentrations of heavy metals in water, mud and fish organs to determine whether these concentrations are allowed and in accordance with normative provisions and considering the pollution by heavy metals if the fish meat is hygienically safe food of animal origin. Concentrations of heavy metals (lead, chromium, manganese, iron, copper and zinc) were determined in water, mud and different organs (liver, kidney, intestine, milt and skin+muscle) of pike (Esox lucius) and European catfish (Silurus glanis) by Energy Dispersive X-Ray Fluorescence method (EDXRF). Statistically significant difference was determined between the concentrations of heavy metals in mud and water (p<0.05) as well as in fish organs (p<0.05). The obtained results show that the highest concentrations of heavy metals were determined in liver and the lowest ones in skin and muscle i.e., in edible fish parts. In accordance with normative regulations of the European Union and the Republic of Croatia, the determined values are lower than the maximally allowed concentrations of heavy metals in fish muscle. When the pollution by heavy metals is taken into account, it indicates that the researched fish meat is hygienically safe food of animal origin.

Zeljka Matasin; Marko Ivanusic; Visnja Orescanin; Srebrenka Nejedli; Ivana Tlak Gajger

2011-01-01

322

LIMING EFFECT ON SOIL HEAVY METALS AVAILABILITY  

Directory of Open Access Journals (Sweden)

Full Text Available The aim of this paper was to determine the influence of acid soils liming and initial soil acidity as well as organic matter content on availability of four heavy metals m(Zn, Pb, Cr and Cd). Liming experiment was conducted in laboratory conditions with six soils of different acidity according to rapid incubation method which was conducted in sealed containers for three days at a constant temperature of 60°C. Liming treatments resulted in trend of heavy metals availability decrement in all soils, but intensity of decrement differed considering initial soil acidity and initial heavy metals availability. According to relative heavy metals availability decrement, liming resulted in the strongest effect in extremely acid soils with the highest initial concentrations of available Zn, Pb, Cr and Cd. On the other side, the weakest relative liming effect on heavy metals availability decrement was recorded in moderately acid soils with the lowest initial concentrations of available heavy metals. Considering impact of initial humus content in soil, higher relative liming efficiency of heavy metals availability decrement was determined in soils with higher soil organic matter content and with lower initial concentrations of available heavy metals.

Krunoslav Karali?; Zdenko Lon?ari?; Brigita Popovi?; Vladimir Zebec; Darko Kerovec

2013-01-01

323

Long range transport of atmospheric heavy metals  

Energy Technology Data Exchange (ETDEWEB)

The paper presents the regional background levels of the atmospheric heavy metals during the long term observation. The input of the heavy metals to the Baltic sea region and Lithuania from the main prevailing wind directions is analysed and estimated. 7 refs., 2 figs.

Kvietkus, K.; Sakalys, J. [Inst. of Physics, Vilnius (Lithuania)

1994-03-01

324

Remoção de metais pesados tóxicos cádmio, chumbo e cromo em biofertilizante suíno utilizando macrófita aquática (Eichornia crassipes) como bioindicador = Removal of toxic heavy metals cadmium, lead and chromium from swine biofertilizer, using an aquatic macrophyte (Eichornia crassipes) as a bioindicator  

Directory of Open Access Journals (Sweden)

Full Text Available Este trabalho objetivou avaliar a eficiência da macrófita aquática (Eichornia crassipes) como bioindicador e alternativa na remoção dos metais pesados tóxicos Cd, Pb e Cr em biofertilizante de origem suína. Foi utilizado o esquema fatorial 2x4, sendo os fatoresrepresentados pelas partes da planta (aérea e raiz), e pelos quatro tratamentos. Na instalação do experimento coletou-se uma alíquota da solução de cada tratamento para determinar as concentrações iniciais dos metais e, após 30 dias de cultivo, as plantas foram retiradas,coletando-se novamente uma alíquota da solução de cada tratamento. As plantas foram separadas em parte aérea e raiz, secas e trituradas. A macrófita apresentou-se eficiente na remoção dos metais pesados, observou-se que o sistema radicular da macrófita apresentoumaiores concentrações de Cd, Pb e Cr. Com este trabalho, conclui-se que a macrófita aquática (Eichornia crassipes) pode ser uma alternativa para o tratamento de biofertilizante e dejetos provenientes da suinocultura.The objective of this work was to evaluate the efficiency of an aquatic macrophyte (Eichornia crassipes) as a bioindicator and as an alternative sorbent for the removal of toxic heavy metals Cd, Pb and Cr from swine biofertilizer. A 2x4 factorial design was used, with the factors represented by plant parts (leaves and roots) and the fourtreatments. The metal concentrations were determined at the beginning of the experiment and after 30 days. The macrophyte showed good efficiency in the removal of toxic heavy metals from swine biofertilizer. It was observed that its radicular system presented larger amounts of Cd, Pb and Cr than did the leaves. Our results show that Eichornia crassipes could be an alternative treatment for biofertilizer and waste from swine culture.

Affonso Celso Gonçalves Júnior; Cléber Antônio Lindino; Maurício Ferreira da Rosa; Reinaldo Bariccatti; Gilmar Divino Gomes

2008-01-01

325

Elaboration, characterization and application of polysulfone and polyacrylic acid blends as ultrafiltration membranes for removal of some heavy metals from water  

Energy Technology Data Exchange (ETDEWEB)

Polysulfone (PSf)/polyacrylic acid ultrafiltration (PSf/PAA) membranes were prepared from a polymer blend in dimethylformamide by coagulation in water according to the wet phase inversion method. Immobilization of water-soluble PAA within the non-soluble PSf matrix was proven by the increase of ion exchange capacity and the intensity of the carboxyl groups' peak with the increase of PAA content as shown by Fourier transform infrared spectra. These results lead to consider that PSf and PAA form a semi-interpenetrating polymer networks. The obtained membranes showed a decrease of mean surface-pore sizes, the overall porosity and the hydraulic permeability with the increase in PAA content. Such results were imputed to the morphologic modifications of PSf film with the immobilization of increasing PAA amount. PSf/PAA membranes showed high lead, cadmium and chromium rejection which reaches 100% at pH superior to 5.7 and a low rejection at low pH. Moreover, the heavy metal rejection decreases with feed solution concentration and applied pressure increases. These behaviors were attributed to the role of carboxylic groups in ion exchange or complexation. As a matter of fact, the strong lead ion-PAA interactions were revealed by the scanning electron microscopy with energy dispersive X-rays (SEM-EDX).

Mbareck, Chamekh, E-mail: chamec1@yahoo.fr [Universite de Nouakchott, Faculte des Sciences et Techniques, B.P. 5026, Nouakchott (Mauritania, Islamic Republic of); Nguyen, Quang Trong; Alaoui, Ouafa Tahiri [P.B.S. Universite de Rouen, 76821 Mont-Saint-Aignan (France); Barillier, Daniel [ERPCB, EA3914, IUT-UFR Sciences, Universite de Caen, 14032 Caen Cedex (France)

2009-11-15

326

Elaboration, characterization and application of polysulfone and polyacrylic acid blends as ultrafiltration membranes for removal of some heavy metals from water  

International Nuclear Information System (INIS)

[en] Polysulfone (PSf)/polyacrylic acid ultrafiltration (PSf/PAA) membranes were prepared from a polymer blend in dimethylformamide by coagulation in water according to the wet phase inversion method. Immobilization of water-soluble PAA within the non-soluble PSf matrix was proven by the increase of ion exchange capacity and the intensity of the carboxyl groups' peak with the increase of PAA content as shown by Fourier transform infrared spectra. These results lead to consider that PSf and PAA form a semi-interpenetrating polymer networks. The obtained membranes showed a decrease of mean surface-pore sizes, the overall porosity and the hydraulic permeability with the increase in PAA content. Such results were imputed to the morphologic modifications of PSf film with the immobilization of increasing PAA amount. PSf/PAA membranes showed high lead, cadmium and chromium rejection which reaches 100% at pH superior to 5.7 and a low rejection at low pH. Moreover, the heavy metal rejection decreases with feed solution concentration and applied pressure increases. These behaviors were attributed to the role of carboxylic groups in ion exchange or complexation. As a matter of fact, the strong lead ion-PAA interactions were revealed by the scanning electron microscopy with energy dispersive X-rays (SEM-EDX).

2009-11-15

327

Heavy metal uptake by agro based waste materials  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english Presence of heavy metals in the aquatic systems has become a serious problem. As a result, there has been a great deal of attention given to new technologies for removal of heavy metal ions from contaminated waters. Biosorption is one such emerging technology which utilized naturally occurring waste materials to sequester heavy metals from industrial wastewater. The aim of the present study was to utilize the locally available agricultural waste materials for heavy metal (more) removal from industrial wastewater. The wastewater containing lead and hexavalent chromium was treated with biomass prepared from ficus religiosa leaves. It was fund that a time of one hr was sufficient for sorption to attain equilibrium. The equilibrium sorption capacity after one hr was 16.95 ± 0.75 mg g-1 and 5.66 ± 0.43 mg g-1 for lead and chromium respectively. The optimum pH was 4 for lead and 1 for chromium. Temperature has strong influence on biosorption process. The removal of lead decreased with increase in temperature. On the other hand chromium removal increased with increase in temperature up to 40ºC and then started decreasing. Ion exchange was the major removal mechanism along with physical sorption and precipitation. The biosorption data was well fitted to Langmuir adsorption model. The kinetics of biosorption process was well described by the pseudo 2nd order kinetics model. It was concluded that adsorbent prepared from ficus religiosa leaves can be utilized for the treatment of heavy metals in wastewater

Qaiser, Suleman; Saleemi, Anwar R; Mahmood Ahmad, Muhammad

2007-07-01

328

Attrition resistant catalysts and sorbents based on heavy metal poisoned FCC catalysts  

Energy Technology Data Exchange (ETDEWEB)

A heavy metal poisoned, spent FCC catalyst is treated by chemically impregnating the poisoned catalyst with a new catalytic metal or metal salt to provide an attrition resistant catalyst or sorbent for a different catalytic or absorption processes, such as catalysts for Fischer-Tropsh Synthesis, and sorbents for removal of sulfur gasses from fuel gases and flue-gases. The heavy metal contaminated FCC catalyst is directly used as a support for preparing catalysts having new catalytic properties and sorbents having new sorbent properties, without removing or "passivating" the heavy metals on the spent FCC catalyst as an intermediate step.

Gangwal, Santosh (Cary, NC); Jothimurugesan, Kandaswamy (Hampton, VA)

1999-01-01

329

A glutathione S-transferase from Proteus mirabilis involved in heavy metal resistance and its potential application in removal of Hg(2+)  

UK PubMed Central (United Kingdom)

Glutathione S-transferases (GSTs) are a family of multifunctional proteins playing important roles in detoxification of harmful physiological and xenobiotic compounds in organisms. In our study, a gene encoding a GST from Proteus mirabilis strain V7, gstPm-4, was cloned and conditionally expressed in Escherichia coli strain BL21(DE3). The purified GstPm-4 protein, with an estimated molecular mass of approximately 23kDa, was able to conjugate 1-chloro-2,4-dinitrobenzene and bind to the GSH-affinity matrix. Real-time reverse transcriptase PCR suggested that mRNA level of gstPm-4 was increased in the presence of CdCl2, CuCl2, HgCl2 and PbCl2, respectively. Correspondingly, overexpression of gstPm-4 in the genetically engineered bacterium Top10/pLacpGst exhibited higher heavy metal resistance compared to the control Top10/pLacP3. Another genetically engineered bacterium Top10/pBATGst, in which the DNA encoding GstPm-4 protein was fused with the DNA encoding Pfa1-based auto surface display system, was built. Top10/pBATGst could constitutively express the chimeric GstPm-4 and anchor it onto the cell surface subsequently. Almost 100% of the Hg(2+) within the range of 0.1-100nM was adsorbed by Top10/pBATGst, and 80% of the bounded Hg(2+) could be desorbed from bacterial cells when pH was adjusted to 6.0. Thus, Top10/pBATGst can be potentially used for efficient treatment of Hg(2+)-contaminated aquatic environment.

Zhang W; Yin K; Li B; Chen L

2013-08-01

330

The reactive surface of Castor leaf [Ricinus communis L.] powder as a green adsorbent for the removal of heavy metals from natural river water  

Science.gov (United States)

In this study, a green adsorbent was successfully applied to remove toxic metals from aqueous solutions. Dried minced castor leaves were fractionated into 63-?m particles to perform characterization and extraction experiments. Absorption bands in FTIR (Fourier Transform Infrared Spectroscopy) spectra at 1544, 1232 and 1350 cm?1 were assigned to nitrogen-containing groups. Elemental analysis showed high nitrogen and sulfur content: 5.76 and 1.93%, respectively. The adsorption kinetics for Cd(II) and Pb(II) followed a pseudo-second-order model, and no difference between the experimental and calculated Nf values (0.094 and 0.05 mmol g?1 for Cd(II) and Pb(II), respectively) was observed. The Ns values calculated using the modified Langmuir equation, 0.340 and 0.327 mmol g?1 for Cd(II) and Pb(II), respectively, were superior to the results obtained for several materials in the literature. The method proposed in this study was applied to pre-concentrate (45-fold enrichment factor) and used to measure Cd(II) and Pb(II) in freshwater samples from the Paraná River. The method was validated through a comparative analysis with a standard reference material (1643e).

Martins, Amanda E.; Pereira, Milene S.; Jorgetto, Alexandre O.; Martines, Marco A. U.; Silva, Rafael I. V.; Saeki, Margarida J.; Castro, Gustavo R.

2013-07-01

331

Stabilization of heavy metals in sludge ceramsite.  

UK PubMed Central (United Kingdom)

This paper attempts to investigate the stabilization behaviours of heavy metals in ceramsite made from wastewater treatment sludge (WWTS) and drinking-water treatment sludge (DWTS). Leaching tests were conducted to find out the effects of sintering temperature, (Fe(2)O(3) + CaO + MgO)/(SiO(2) + Al(2)O(3)) (defined as F/SA ratios), pH, and oxidative condition. Results show that sintering exhibits good binding capacity for Cd, Cr, Cu, and Pb in ceramsite and leaching contents of heavy metals will not change above 1000 degrees C. The main crystalline phases in ceramsite sintered at 1000 degrees C are kyanite, quartz, Na-Ca feldspars, sillimanite, and enstatite. The main compounds of heavy metals are crocoite, chrome oxide, cadmium silicate, and copper oxide. Leaching contents of Cd, Cu, and Pb increase as the F/SA ratios increase. Heavy metals in ceramsite with variation of F/SA ratios are also in same steady forms, which prove that stronger chemical bonds are formed between these heavy metals and the components. Leaching contents of heavy metals decrease as pH increases and increase as H(2)O(2) concentration increases. The results indicate that when subjected to rigorous leaching conditions, the crystalline structures still exhibit good chemical binding capacity for heavy metals. In conclusion, it is environmentally safe to use ceramsite in civil and construction fields.

Xu GR; Zou JL; Li GB

2010-05-01

332

Stabilization of heavy metals in sludge ceramsite.  

Science.gov (United States)

This paper attempts to investigate the stabilization behaviours of heavy metals in ceramsite made from wastewater treatment sludge (WWTS) and drinking-water treatment sludge (DWTS). Leaching tests were conducted to find out the effects of sintering temperature, (Fe(2)O(3) + CaO + MgO)/(SiO(2) + Al(2)O(3)) (defined as F/SA ratios), pH, and oxidative condition. Results show that sintering exhibits good binding capacity for Cd, Cr, Cu, and Pb in ceramsite and leaching contents of heavy metals will not change above 1000 degrees C. The main crystalline phases in ceramsite sintered at 1000 degrees C are kyanite, quartz, Na-Ca feldspars, sillimanite, and enstatite. The main compounds of heavy metals are crocoite, chrome oxide, cadmium silicate, and copper oxide. Leaching contents of Cd, Cu, and Pb increase as the F/SA ratios increase. Heavy metals in ceramsite with variation of F/SA ratios are also in same steady forms, which prove that stronger chemical bonds are formed between these heavy metals and the components. Leaching contents of heavy metals decrease as pH increases and increase as H(2)O(2) concentration increases. The results indicate that when subjected to rigorous leaching conditions, the crystalline structures still exhibit good chemical binding capacity for heavy metals. In conclusion, it is environmentally safe to use ceramsite in civil and construction fields. PMID:20219229

Xu, G R; Zou, J L; Li, G B

2010-02-16

333

Heavy metals in municipal solid waste deposits  

Energy Technology Data Exchange (ETDEWEB)

Extensive use of heavy metals in modern society influences routes followed by fluxes on the surface of the Earth. The changed flow paths may be harmful for the balance of biological systems at different levels, micro-organisms, human beings and whole ecosystems, since the toxicity of heavy metals is determined by their concentrations and chemical forms. Despite the low mobility of heavy metals (Zn, Cu, Pb, Cr, Ni and Cd) in municipal landfills, it was found that extensive transformations of the binding forms of heavy metal take place within the waste mass during the degradation of the waste. These changes appear to be closely related to the development of early diagenetic solid phases, i.e. new secondary solid phases formed in the waste. The heavy metals often constitute a minor part of these phases and the bindings include several forms such as adsorption, complexation, coprecipitation, precipitation, etc. It was also found that the associations between heavy metals and solid phases are dominated by several binding forms to one specific substrate rather than bindings to various solid phases. The mobility of iron and manganese seems to increase during the processes involved in waste degradation due to the solution of oxide/hydroxide phases, while the heavy metals appear to become less mobile due to their binding to organic compounds and sulphides. However, one exception in this case may be nickel. Another aspect of the transformation of heavy metals is the accumulation of pools of heavy metals which can become susceptible to environmental changes, such as oxidation or acidification. However, the risk of increased mobilization caused by lower pH values seem to be limited since municipal solid waste has a large buffer capacity. 66 refs, 9 figs, 3 tabs 66 refs, 9 figs, 3 tabs

Flyhammar, P.

1997-12-01

334

Biosorption of heavy metals from wastewater by biosolids  

Energy Technology Data Exchange (ETDEWEB)

In a study where the removal of heavy metals from wastewater is the primary aim, the biosorption of heavy metals onto biosolids prepared as Pseudomonas aeruginosa immobilized onto granular activated carbon was investigated in batch and column systems. In the batch system, adsorption equilibriums of heavy metals were reached between 20 and 50 min, and the optimal dosage of biosolids was 0.3 g/L. The biosorption efficiencies were 84, 80, 79, 59 and 42 % for Cr(VI), Ni(II), Cu(II), Zn(II) and Cd(II) ions, respectively. The rate constants of biosorption and pore diffusion of heavy metals were 0.013-0.089 min{sup -1} and 0.026-0.690 min{sup -0.5}. In the column systems, the biosorption efficiencies for all heavy metals increased up to 81-100 %. The affinity of biosorption for various metal ions towards biosolids was decreased in the order: Cr = Ni > Cu > Zn > Cd. (Abstract Copyright [2006], Wiley Periodicals, Inc.)

Orhan, Y.; Bueyuekguengoer, H. [Ondokuz Mayis University, Engineering Faculty, Environmental Engineering Department, 55139 Samsun (Turkey); Hrenovic, J. [University of Zagreb, Faculty of Science, Department of Biology, Rooseveltov trg 6, 10000 Zagreb (Croatia)

2006-08-15

335

Heavy metal content of cereals and potatoes  

Energy Technology Data Exchange (ETDEWEB)

By means of atomic absorption spectrometry, the cadmium, zinc, copper and manganese contents was determined in potatoes and cereals from three territories differently burdened by heavy-metal emissions. Of these elements, cadmium was most enriched, followed by zinc and copper, whereas the manganese level was slightly high in the burdened region. On the basis of the results obtained and of data from the literature, an estimate is calculated for the expected values in territories differently burdened by heavy-metal emissions. Finally, targeted suggestions are given for preventing or impeding the entrance of heavy metals into the biocycle.

Auermann, E.; D' assler, H.G.; Jacobi, J.; Cumbrowski, J.; Meckel, U.

1980-01-01

336

Study on Biosorption of Heavy Metals by Modified Lignocellulosic Waste  

Directory of Open Access Journals (Sweden)

Full Text Available Heavy metal laden effluent coming out of various industries is posing a huge pressure on the environment. This in turn, necessitates the development of a noble low cost and efficient technology for the removal of such wastes from industrial effluents. In this particular research, the heavy metal (lead (II) biosorption capacity of modified agri-waste (rice husk and sugarcane bagasse) has been studied, taking the two biosorbents as abundant and low cost biosorbents with promising potential to remove hazardous heavy metal wastes from effluent streams. In the study, options to enhance metal sorption capacity by chemical and thermal modification of the sorbents have been investigated. Impact of modifier chemicals used include sodium hydroxide, sulfuric acid, nitric acid, citrc acid, acrylic acid and glutamic acid in case of rice husk and modifiers like Sodium Dodecyl Sulfate (SDS), Sodium bicarbonate, Cetyl trimethyl diammonium bromide (CTAB), sodium methylate and urea, in case of sugar cane bagasse in addition to those used with rice husk. Characterization of the sorbents surfaces has been made before and after chemical and thermal modification and after sorption of heavy metals using Fourrier Transform Infra-Red Spectroscopy (FTIR) and Scanning Electron Microscope (SEM). Some studies have also been done on mechanism of sorption. In addition impact of concentration of sodium hydroxide and citric acid as effective chemical modifier has been studied. Tests to understand impact of particle size have also been conducted and results for the two biosorbents have been compared.

A. Mesfin Yeneneh; S. Maitra; Usama Eldemerdash

2011-01-01

337

Heavy metal welding protection glass  

UK PubMed Central (United Kingdom)

The invention relates to a heavy metal electric welding protective lens with uvioresistant and anti-infrared function used on a welding mask, which is prepared by the following material according to parts by weight: 60-80 parts of quartz sand, 6-10 parts of ferric oxide, 1-4 parts of cerium oxide, 0.5-2 parts of cobalt oxide, 8-10 parts of calcined soda, 3-5 parts of calcite, 1-2 parts of nickel oxide and 2-5 parts of manganese powder, and has the advantages of uvioresistant and anti-infrared. The invention can resist the infrared, the ultraviolet radiation and the harmful light, and visible light can be passed, simultaneously, the visible light of a welding object filtered by the lens of the invention can be comfortably observed by welder, the ultraviolet transmittance of the invention is between 313nm to 365nm, and the infrared transmittance is between 780nm to 1300nm or 1300nm to 2000nm, thus conforming with the requirement of national standard.

XINJING HE

338

HEAVY METAL REDUCTION IN PLANTA  

UK PubMed Central (United Kingdom)

There is described a mutant, non-naturally occurring or transgenic plant or plant cell comprising (a) a polynucleotide selected from the group consisting of: (i) a polynucleotide comprising, consisting or consisting essentially of a sequence having at least 71 % sequence identity to SEQ ID NOs: 1, 2, 27, 28 or 29 or 51 or (ii)a polynucleotide comprising, consisting or consisting essentially of a sequence having at least 65 % sequence identity to any of SEQ ID NOs: 3 to 23 or 30 to 50 or (iii) a polynucleotide encoding a NtMRP polypeptide comprising, consisting or consisting essentially of a sequence having at least 65% sequence identity to any of SEQ ID NOs. 24 to 26 or 52, and wherein the polypeptide has heavy metal transporter activity or (b) a polynucleotide construct of at least 15 contiguous nucleotides in length that is at least 65 % identical to a region of any of SEQ ID NOs: 1 to 23 or 27 to 51 or (c) a double-stranded RNA comprising at least two sequences that are at least partially complementary to each other and wherein a sense strand comprises a first sequence and an antisense strand comprises a second sequence and wherein at least one of the sequences comprises at least 10 contiguous nucleotides of NtMRP RNA or (d) an expression vector comprising the polynucleotide as set forth in (i), (ii) or (iii) or the polynucleotide construct as set forth in (b).

BOVET LUCIEN

339

Experimental perspectives on heavy electron metals  

Energy Technology Data Exchange (ETDEWEB)

We motivate the description of heavy electron metals in terms of concepts from the Kondo problem. These concepts are used to discuss magnetism and superconductivity in heavy electron systems. Particular attention is given to what we view as the principal outstanding questions in this field and direction in which the field is developing. This will include consideration of the differences between Ce and U heavy electron compounds, as well as the occurrence of very small ordered magnetic moments. 26 refs., 5 figs.

Fisk, Z.; Ott, H.R.; Aeppli, G.

1987-01-01

340

Heavy metals and PAH in the atmosphere  

Energy Technology Data Exchange (ETDEWEB)

This article presents the results of the air pollution observations made at several background stations in the former USSR. The monitored elements were heavy metals and the monitored compounds were polycyclic aromatic hydrocarbon

Brukhanov, P. [Inst. of Global Climate and Ecology, Moscow (Russian Federation)

1995-12-31

 
 
 
 
341

Heavy metals and living systems: An overview.  

UK PubMed Central (United Kingdom)

Heavy metals are natural constituents of the earth's crust, but indiscriminate human activities have drastically altered their geochemical cycles and biochemical balance. This results in accumulation of metals in plant parts having secondary metabolites, which is responsible for a particular pharmacological activity. Prolonged exposure to heavy metals such as cadmium, copper, lead, nickel, and zinc can cause deleterious health effects in humans. Molecular understanding of plant metal accumulation has numerous biotechnological implications also, the long term effects of which might not be yet known.

Singh R; Gautam N; Mishra A; Gupta R

2011-05-01

342

Method of heavy metal trapping and separating  

International Nuclear Information System (INIS)

The use is described of pearl cellulose and the derivatives thereof for heavy metal sorption and separation. At pH 3 to 8, an aqueous solution containing heavy metals of the transition and post-transition metals of the 4th to 7th periods, this to advantage U, Cu, Pb, Cd, Hg, is passed through a layer of pearl cellulose with sorption-active hydroxyl, phosphate, carboxy methyl, amine, acetamide, imidazole, guanidine or thiol groups. Metal separation proceeds at pH 1 to 9; at pH 0.1 to 1 cellulose regenerates. (B.S.)

1981-01-01

343

Mechanisms of heavy metal-induced autoimmunity.  

Science.gov (United States)

Chemical exposure can trigger or accelerate the development of autoimmune manifestations. Although heavy metals are elementary chemical structures, they can have profound and complex effects on the immune system. In genetically susceptible mice or rats, administration of subtoxic doses of mercury induces both the production of highly specific autoantibodies and a polyclonal activation of the immune system. We review in this article some of the mechanisms by which heavy metal exposure can lead to autoimmunity. PMID:15829271

Rowley, Benjamin; Monestier, Marc

2005-05-01

344

Mechanisms of heavy metal-induced autoimmunity.  

UK PubMed Central (United Kingdom)

Chemical exposure can trigger or accelerate the development of autoimmune manifestations. Although heavy metals are elementary chemical structures, they can have profound and complex effects on the immune system. In genetically susceptible mice or rats, administration of subtoxic doses of mercury induces both the production of highly specific autoantibodies and a polyclonal activation of the immune system. We review in this article some of the mechanisms by which heavy metal exposure can lead to autoimmunity.

Rowley B; Monestier M

2005-05-01

345

Heavy metal stabilization in municipal solid waste incineration flyash using heavy metal chelating agents.  

UK PubMed Central (United Kingdom)

Heavy metal chemical stabilization with synthesized heavy metal chelating agent was assessed for flyash from municipal solid waste incinerator. Flyash can contain heavy metals (e.g. Pb, Cd) which can leach. A new kind of heavy metal chelating agent showed more attractive competition than inorganic chemicals in stabilizing flyash. The synthesizing method of this kind of heavy metal chelating agent was explained in this paper, and the technology process and treatment efficiency of the chelating agent in treating flyash were experimentally studied, which was compared with the results of inorganic chemical agents such as sodium sulfide and lime. The heavy metals in flyash were stabilized more effectively by using heavy metal chelating agents than by using sodium sulfide and lime, furthermore, the stabilized products using the chelating agents can meet the landfill disposal controlling standards for heavy metal waste. pH-dependent leaching experiment showed the stabilized flyash by treatment with heavy metal chelating agent could keep long-term stabilization within a broad range of pH value. Thus, the risk of secondary pollution for the stabilized products was reduced dramatically when the environment condition changes during its disposal period.

Jianguo J; Jun W; Xin X; Wei W; Zhou D; Yan Z

2004-09-01

346

HEAVY METALS IN PRODUCTIVE PARTS OF AGRICULTURAL PLANTS  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The contents of heavy metals in plants were not in relation to contents of heavy metals in soil. Increased content of heavy metals in soils was not in consistency with content in plants. Usually content of heavy metals in plants according to our results were lower than their content in soil. Only t...

Ján Tomáš; Július Árvay; Tomáš Tóth

347

Bioaccumulation of heavy metals in fauna from wet detention ponds for stormwater runoff  

DEFF Research Database (Denmark)

Stormwater detention ponds remove pollutants e.g. heavy metals and nutrients from stormwater runoff. These pollutants accumulate in the pond sediment and thereby become available for bioaccumulation in fauna living in the ponds. In this study the bioaccumulation was investigated by fauna samples from 5 wet detention ponds for analyses of heavy metal contents. Five rural shallow lakes were included in the study to survey the natural occurrence of heavy metals in water-dwelling fauna. Heavy metal concentrations in water-dwelling fauna were generally found higher in wet detention ponds compared to rural shallow lakes.

Stephansen, Diana; Nielsen, AsbjØrn Haaning

2012-01-01

348

Evaluación de la eficiencia de una batería de filtros empacados en zeolita en la remoción de metales pesados presentes en un licor mixto bajo condiciones de laboratorio Evaluation of efficiency of a filter battery packaging zeolite in the removal of heavy metals in a mixed liquor under laboratory conditions  

Directory of Open Access Journals (Sweden)

Full Text Available En este artículo se muestran resultados de investigación obtenidos en la remoción de los metales pesados, plomo, níquel, cromo, cadmio y mercurio, presentes en una solución compuesta por licor mixto proveniente de la planta de tratamiento de aguas residuales de San Fernando y una solución preparada con metales pesados con una concentración conocida, mediante el uso de una batería de filtros empacados en zeolita clinoptilolita. La experimentación se desarrolló bajo condiciones controladas de caudal y pH, a temperatura ambiente. Se encontró que la eficiencia de los filtros bajo las condiciones específicas de diseño es significativamente alta en la remoción de los metales pesados evaluados en la solución acuosa. Se encontró, además, que sin importar el valor de la concentración inicial, se obtuvo una remoción importante en los contaminantes luego de pasar por los filtros con una mayor eficiencia en la remoción del mercurio.This article shows the research results on the removal of five heavy metals (lead, nickel, chromium, cadmium and mercury) present in a liquor made of a mixture of wastewater from San Fernando wastewater treatment plant and a solution prepared with known concentrations of heavy metals, using a series of batery filters packed with zeolita clinoptilolita. The experiments were run under controlled conditions of flow and pH, at room temperature. It was found that the removal efficiency was significantly high under the specified design conditions; also, it was found an important removal of the contaminants after passing through the filters, independently of the initial concentration, with the highest observed removal for mercury.

Diana Rocío Acevedo Cifuentes; Sandra Milena Builes Felizzola; Carlos Andrés Ordóñez Ante; Idalia Jacqueline López Sánchez

2011-01-01

349

Plant transporters involved in heavy metal homeostasis  

Directory of Open Access Journals (Sweden)

Full Text Available Transition metal ions (predominately manganese, iron, cobalt, nickel, copper and zinc) havean array of catalytic and regulatory roles in the growth and development of all living organisms.However, an excess of these metal ions can also be toxic to any life form and therefore every cell andwhole organism needs to maintain the concentration of these essential nutrient metals within a narrowrange: a process known as metal homeostasis. Heavy metal ions are taken up into cells by selectivetransporters and as they cannot be degraded, the “desired” levels of metal ions are achieved by anumber of strategies that involve: chelation, sequestration and export out of the cell. Cation DiffusionFacilitators (CDF) is a large family of transporters involved in maintaining the cytosolic metalconcentration. They transport different heavy metal divalent ions, but exhibit main affinity for zinc, ironand manganese. Metal Tolerance Proteins (MTPs) are a subfamily of the Cation Diffusion Facilitator (CDF)family found in plants. There has been much interest in these heavy metal transporters in order toprovide an insight into plant metal homeostasis, which has significant implications in human health andphytoremediation. Although data regarding the CDFs/MTPs mechanism is gathering there is still littleinformation with respect to metal selectivity determinants.

Dorina Podar

2010-01-01

350

Biorreagentes: aplicações na remoção de metais pesados contidos em efluentes líquidos por biossorção/bioflotação/ Bioreagents: their use in the removal of heavy metals from liquid streams by biosorption/ bioflotation  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese Esse trabalho tem o objetivo de apresentar uma análise dos principais aspectos sobre o uso de biomassas como biorreagentes na remoção de metais pesados contidos em efluentes líquidos. As vantagens de se utilizarem biossorventes ao invés de sorventes convencionais estão notadamente na relação custo-benefício inerente a essa tecnologia contemporânea. Algas, bactérias, fungos e materiais biológicos em geral (casca de coco, madeira, turfa, etc.) têm revelado avid (more) ez na captura de íons metálicos em ambientes aquosos, sendo que sua ubiqüidade diminui o custo total de sistemas de tratamento. Exemplos de pesquisas e patentes são discutidos, demonstrando o sucesso dessa tecnologia emergente. Abstract in english The objective of this work is to present a review concerning the use of biomass as bioreagents in the removal of heavy metals while treating liquid effluents. The advantages of using these biosorbents instead of conventional sorbents lie on the cost benefit relations inherent in this recent technology. Algae, bacteria, fungi and biological materials (coconut shells, wood, peat etc.) have shown avidity for metal ion uptaking in aqueous environments and their ubiquity decre (more) ases the overall treatment system cost. Research and patent examples are discussed, showing the success of this emergent technology.

Calfa, Bruno Abreu; Torem, Maurício Leonardo

2007-09-01

351

A biosystem for removal of metal ions from water  

Energy Technology Data Exchange (ETDEWEB)

The presence of heavy metal ions in ground and surface waters constitutes a potential health risk and is an environmental concern. Moreover, processes for the recovery of valuable metal ions are of interest. Bioaccumulation or biosorption is not only a factor in assessing the environmental risk posed by metal ions; it can also be used as a means of decontamination. A biological system for the removal and recovery of metal ions from contaminated water is reported here. Exopolysaccharide-producing microorganisms, including a methanotrophic culture, are demonstrated to have superior metal binding ability, compared with other microbial cultures. This paper describes a biosorption process in which dried biomass obtained from exopolysaccharide-producing microorganisms is encapsulated in porous plastic beads and is used for metal ion binding and recovery. 22 refs., 13 figs.

Kilbane, J.J. II.

1990-01-01

352

Polymers contamination by heavy metal compounds  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The contamination of important synthetic (surface unmodified) polymers by various heavy metal compounds (such as copper, manganese and lead) in aqueous medium was investigated in this study. The influence of the pH of the aqueous medium, temperature and metal type on contamination was investigated d...

Jovani? Saša; Stoiljkovi? Dragoslav M.; Popovi? Ivanka G.

353

Adsorption of Heavy Metal from Recovered base Oil using Zeolite  

Directory of Open Access Journals (Sweden)

Full Text Available Recovery of used lubricating oil by extraction produced organic sludge and recovered base oil, but this oil has metallic content such as magnesium and zinc. In this study, purification of recovered base oil by using adsorption process to remove heavy metals was performed. Zeolite was used as an adsorbent. The parameters studied were contact time, amount of zeolite, temperature and their interactions. The results showed that zinc removal was higher than that of the magnesium. The optimum magnesium and zinc removal obtained were 50 and 62%, respectively. The most influential parameter affecting the magnesium and zinc removal was the time of adsorption. Further investigations on the optimum conditions will be performed.

S.M.W. Ali; A. Ripin; A. Ahmad

2010-01-01

354

Investigating the evaporation of heavy metals from fly ash by thermo-desorption spectrometry  

Energy Technology Data Exchange (ETDEWEB)

Our research is devoted to better understanding the evaporation process of the heavy metals cadmium, copper, lead, and zinc from toxic filter ash of municipal solid waste incinerators. This knowledge is used for optimising the heavy metal removal from the ash by a thermal process - the final goal being the detoxification of the ash. The evaporation rates obtained from the thermo-desorption spectra (TDS) gave valuable insight into the chemical reaction mechanisms. Especially interesting from a point of view of heavy metal removal by evaporation is the role of chlorides like sodium chloride (NaCl). They reacted with non-volatile heavy metal species (like oxides) to form volatile heavy metal chlorides. (author)

Lutz, H.; Ludwig, C.; Struis, R.; Stucki, S.

2001-03-01

355

Surfactant biocatalyst for remediation of recalcitrant organics and heavy metals  

Energy Technology Data Exchange (ETDEWEB)

Novel strains of isolated and purified bacteria have been identified which have the ability to degrade petroleum hydrocarbons including a variety of PAHs. Several isolates also exhibit the ability to produce a biosurfactant. The combination of the biosurfactant-producing ability along with the ability to degrade PAHs enhances the efficiency with which PAHs may be degraded. Additionally, the biosurfactant also provides an additional ability to bind heavy metal ions for removal from a soil or aquatic environment.

Brigmon, Robin L. (North Augusta, SC); Story, Sandra (Greenville, SC); Altman, Denis J. (Evans, GA); Berry, Christopher J. (Aiken, SC)

2011-03-15

356

Surfactant biocatalyst for remediation of recalcitrant organics and heavy metals  

Energy Technology Data Exchange (ETDEWEB)

Novel strains of isolated and purified bacteria have been identified which have the ability to degrade petroleum hydrocarbons including a variety of PAHs. Several isolates also exhibit the ability to produce a biosurfactant. The combination of the biosurfactant-producing ability along with the ability to degrade PAHs enhances the efficiency with which PAHs may be degraded. Additionally, the biosurfactant also provides an additional ability to bind heavy metal ions for removal from a soil or aquatic environment.

Brigmon, Robin L. (North Augusta, SC); Story, Sandra (Greenville, SC); Altman; Denis J. (Evans, GA); Berry, Christopher J. (Aiken, SC)

2011-03-29

357

Surfactant biocatalyst for remediation of recalcitrant organics and heavy metals  

Energy Technology Data Exchange (ETDEWEB)

Novel strains of isolated and purified bacteria have been identified which have the ability to degrade petroleum hydrocarbons including a variety of PAHs. Several isolates also exhibit the ability to produce a biosurfactant. The combination of the biosurfactant-producing ability along with the ability to degrade PAHs enhances the efficiency with which PAHs may be degraded. Additionally, the biosurfactant also provides an additional ability to bind heavy metal ions for removal from a soil or aquatic environment.

Brigmon, Robin L. (North Augusta, SC); Story, Sandra (Greenville, SC); Altman, Denis J. (Evans, GA); Berry, Christopher J. (Aiken, SC)

2011-05-03

358

Heavy metal contaminants in yerberia shop products.  

UK PubMed Central (United Kingdom)

Complementary and alternative medications, including the use of herbal medications, have become quite popular in the USA. Yerberias are found throughout the southwest and specialize in selling Hispanic herbal products. The products sold in these stores are not regulated by any governmental agency. Previous reports have found Ayurvedic medications contain high levels of lead, mercury, and arsenic. The primary purpose of this study is to examine the prevalence of heavy metal contaminants sold at Yerberia stores in the southwest. Yerberias in the Phoenix, Arizona area were identified via search of an on-line search engine using the words "Yerberia Phoenix." Every second store was selected, and products were purchased using a standard script. The products were subsequently analyzed for mercury, lead, and arsenic. The main outcome is the prevalence of heavy metal content in over-the-counter "cold" medications purchased at a Yerberia. Twenty-two samples were purchased. One product contained pure camphor (2-camphone) and was subsequently not further analyzed. Of the 21 samples analyzed, lead was found in 4/21 (19.4 %). Arsenic and mercury were in 1/21 (4.8 %) each. Because two samples contained two heavy metals, the total prevalence of heavy metals was 4/21 (19.4). Heavy metal contaminants are commonly encountered in over-the-counter herbal "cold" medications purchased at Yerberias in the southwest.

Levine M; Mihalic J; Ruha AM; French RN; Brooks DE

2013-03-01

359

Design consideration for tungsten heavy metal  

Energy Technology Data Exchange (ETDEWEB)

Tungsten was rarely known to industry before 1909 when it was utilized as electric wire filament in the incandescent lamp. Up to 1927, tungsten was mainly employed in the manufacture of tool steels. In 1935, the first tungsten heavy metal pseudoalloys were produced by utilizing the powder metallurgy process of liquid-phase sintering. Tungsten is now the most economical material available for applications requiring the use of a high-density material. Some of the applications of tungsten heavy metal are related to aircraft counter-weights and missile ballast. A large increase in the tungsten provided by Canada and additional output from Mexico will make North America self-sufficient with respect to its needs for tungsten starting in 1985. Attention is given to heavy metal metallurgy, tungsten heavy metal alloy systems, and physical properties. In connection with the design of objects consisting of tungsten heavy metal, aspects of linear shrinkage have to be considered along with material density variations, and the maximum material condition concept.

Maurer, W.E.

1982-01-01

360

Direct voltammetric determination of some heavy metals in uranium  

International Nuclear Information System (INIS)

[en] The formation of strong complexes between uranium(VI) and various ligands was investigated and a method for the determination of some heavy metals in uranium by differential-pulse stripping voltammetry at a hanging mercury drop electrode was developed. It was found that a carbonate buffer shows the strongest affinity for Usup(VI) and gives the greatest linearity and the best separation between the voltammetric peaks of heavy metal impurities. The concentration of carbonate markedly affects the reduction of the major and the oxidation of the minor constituents of the uranium samples. In 0.1 M carbonate buffer solution (pH 10.0), copper, bismuth, antimony, thallium, lead, cadmium, indium, tin and nickel could be determined at the p.p.b. level without the removal of the uranium matrix. Uranium metal and some uranium(IV) compounds were analysed and good agreement with results obtained by atomic absorption spectrometry was found. (author)

1987-01-01