The availability and binding of heavy metals in compost derived from household waste

Organic waste can be recycled as compost which has traditionally been used as a soil improver. As more waste is recycled as compost, it is becoming increasingly important to find alternative uses for compost. Leachability data are used to determine the environmental availability of Cd, Cu, Pb, and Zn contained in natural compost. Batch sorption data are used to determine uptake of additional Cd, Cu, Pb, and Zn by compost and assess its potential use in remediation work, as an alternative to natural materials such as peat. The relative binding of these additional metals to compost is found to be in the order Pb > Cd ≈ Cu > Zn. The sorption of metals on compost takes place, at least in part, by exchange of calcium bound to the compost and there is evidence that the sorption occurs in both humic and non‐humic sites in the compost. The use of compost to bind metals in remediation work is discussed. © 1999 Society of Chemical Industry     

Interference of aluminum in heavy metal biosorption by a seaweed biosorbent

Heavy metal and Al sorption capacities of Ca-loadedSargassum fluitans biomass were studied by using equilibrium methodology. An evaluation of sorption performance and modeling in a two-metal system was carried out with a modified multi-component Langmuir isotherm. The maximum uptakes of Cr, Pb, Cu, Cd, Zn and Al calculated from the Langmuir isotherm were 1.74 mmol/g, 1.65 mmol/g, 1.61 mmol/g, 1.15 mmol/g, 0.81 mmol/g, and 2.95 mmol/g at pH 4.5, respectively. The interference of Al in heavy metal biosorptive uptakes was assessed by ‘cutting’ the three-dimensional uptake isotherm surfaces at constant second-metal final concentrations. The reduction of Pb, Cu, Zn, Cd and Cr uptakes at its final equilibrium concentrations of 1 mM at pH 4.5 was 78.4%, 82.7%, 85.1%, 89.8% and 51.2% in the presence of 1mM Al ion, respectively. The presence of Al ion greatly affected the uptake of all heavy metals tested except Cr.     

Comparison of Heavy Metal Removal from Chemically Interactive and Non-Interactive Solid Phases by the CEHIXM Process

A laboratory study was conducted to compare the removal of heavy metals from chemically interactive and non-interactive solid phases using coupled electric-hydraulic gradient assisted by ion exchange medium (CEHIXM) process. The removal of primarily four heavy metals Pb, Cd, Zn, and Mn from the contaminated sources was investigated. Experiments were conducted at a constant electric field of 50 V DC for both the solid phases and with constant hydraulic flow-rates of 10 cm³/min for chemically non-interactive solid phase and 4 cm³/min for chemically interactive solid phase. As much as 93% of Pb, 97% of Cd, 98% of Zn, and 94% of Mn were removed after 100 hours of the processing from chemically non-interactive solid phase. About 72% of Pb, 85% of Cd, 81% of Zn, and 77% of Mn were removed after 100 hours of the processing and about 90% of Pb, 96% of Cd, 93% of Zn, and 91% of Mn were removed after 200 hours of the processing from chemically interactive solid phase. Metal removal percentage was always higher for chemically non-interactive solid phase than that of chemically interactive solid phase. Chemically interactive solid phase required prolonged experiment duration to achieve compatible metal removal. The two solid phases did not follow quite the same order of metal removal. The order of removal was Zn > Cd > Mn > Pb for chemically non-interactive solid phase and Cd > Zn > Mn > Pb for chemically interactive solid phase.     

The interaction between Cu,Pb, Zn and Ni in their biosorption onto polyurethane‐immobilised Sphagnum moss

The uptake of Cu(II), Pb(II), Zn(II) and Ni(II) was investigated both individually and from mixed metal ion solutions using Sphagnum moss biomass immobilised in a polyurethane support. The data were evaluated using the Langmuir isotherm equation, and sorption capacities were calculated for different concentration ranges. It was concluded that care must be taken in presentation and interpretation of results when this modelling approach is applied at low concentrations. Repeated metal loading cycles also gave lower values for sorption capacity compared with the maximum potential value, due to equilibrium effects. The uptake capacity for the different metals on a weight basis was in the order lead > copper > zinc > nickel, but on a molar basis this changed to copper > lead > nickel > zinc. Sorption from a multi‐component metal system showed that lead and copper competed equally for binding sites and much more effectively than zinc and nickel. Equations were derived to predict the percentage effect on a given metal ion of other metals in a multi‐metal system based their behaviour in the relevant single and binary systems. Copyright © 2005 Society of Chemical Industry     

Packed-bed columns with dye-affinity microbeads for removal of heavy metal ions from aquatic systems

A dye ligand Cibacron Blue F3GA, was covalently coupled with polyhydroxyethylmethacrylate (PHEMA) microbeads in the 150–200 μm particle size range. The sorbent carrying 22.3 μmol Cibacron Blue F3GA per gram of polymer was then used to remove Pb(II), Cd(II), Cu(II) and Zn(II) from aqueous solutions in a packed-bed column system. Heavy metal ion adsorption capacity of the column was investigated as a function of heavy metal ion-bearing solution flow rate and the inlet heavy metal ion concentration. The maximum metal ion uptake values found were: 80.60, 96.98, 78.36, 103.98 μmol/g polymer for Pb(II), Cd(II), Cu(II) and Zn(II), respectively. The heavy metal adsorption capacity of the microbeads decreased with an increase in the circulation rate of aqueous solution. The order of affinity based on molar uptake was Zn(II)>Cd(II)>Pb(II)>Cu(II). Removal percentages of heavy metals related to flow time were determined for different flow rates and initial metal ion concentrations. It was observed that PHEMA microbeads carrying Cibacron Blue F3GA can be regenerated by washing with a solution of nitric acid (0.05 M). The desorption ratio was as high as 98.5%.     

Polyacrylate anion exchangers in sorption of heavy metal ions with non-biodegradable complexing agents

The polyacrylate anion exchangers are widely used in purification of heavy metal ions from wastewaters and different accompanying complexing agents. Such effluents containing the chelators (EDTA, NTA, HEDTA, DTPA, and IDA) are discharged from relevant industries such as printed circuits boards, plating on plastics, metal finishing and others. The sorption was studied as a function of phase contact time and pH by the batch technique. It was found that the removal of heavy metal ions in the presence of EDTA, NTA and IDA strictly depends on the phase contact time and pH values. Various kinetic models such as the pseudo first-order and the pseudo second-order as well as the intraparticle one were also tested to estimate the sorption rate. The equilibrium capacities of the studied anion exchangers for Cu(II), Zn(II), Co(II), Ni(II), Pb(II) and Cd(II) in the presence of EDTA were the highest for Pb(II) and Cd(II). The order of sorption for Amberlite IRA 458, Amberlite IRA 958 as well as Amberlite IRA 67 can be as follows: Pb(II) > Cd(II) > Zn(II) > Cu(II) > Ni(II) > Co(II). The stability of forming complexes was also compared. The estimation of the capacities of anion exchangers under investigation by the continuous column studies was also carried out.     

Cysteine-metal affinity chromatography: determination of heavy metal adsorption properties

Various adsorbent materials have been reported in the literature for heavy metal removal. We have developed a novel approach to obtain high metal sorption capacity utilising cysteine containing adsorbent. Metal complexing aminoacid-ligand cysteine was immobilised onto poly(hydroxyethylmethacrylate) (PHEMA) microbeads. PHEMA-cysteine affinity microbeads containing 0.318 mmol cysteine/g were used in the removal of heavy metal ions (i.e. copper, lead and cadmium) from aqueous media containing different amounts of these ions (50–400 mg/l for Pb(II) and Cd(II), 25–60 mg/l for Cu(II)) and at different pH values (4.0–7.0). The maximum adsorption capacity of heavy metal ions onto the cysteine-containing microbeads under non-competitive conditions were 0.259 mmol/g for Pb(II), 0.330 mmol/g for Cd(II) and 0.229 mmol/g for Cu(II). The affinity order was observed as follows: Cd(II)>Pb(II)>Cu(II). The competitive adsorption capacities of the heavy metals were 0.260 mmol/g for Cd(II) and 0.120 mmol/g for Cu(II). Pb(II) adsorption onto cysteine-immobilised microbeads was zero under competitive conditions. The affinity order was as follows: Cd(II)>Cu(II)>Pb(II). The formation constants of cysteine–metal ion complexes have been investigated applying the method of Ruzic. The calculated value of stability constants were 1.75×10⁴ l/mol for Pb(II)–cysteine complex and 4.35×10⁴ l/mol for Cd(II)–cysteine complex and 1.39×10⁴ l/mol for Cu(II)–cysteine complex. PHEMA microbeads carrying cysteine can be regenerated by washing with a solution of hydrochloric acid (0.05 M). The maximum desorption ratio was greater than 99%. These PHEMA microbeads are suitable for repeated use for more than three adsorption–desorption cycles without considerable loss in adsorption capacity.     

Hexafunctional poly(propylene glycol) based hydrogels for the removal of heavy metal ions

Two types of degradable poly(propylene glycol) (PPG) hydrogels that are suitable for the absorption of heavy metals have been presented. The PPG‐O‐P(O)Cl₂ fragments obtained by treating hexafunctional PPG with phosphorous oxychloride (POCl₃) react with 1,3‐propanediamine (PDA; Gel‐1 ) or PDA together with 1,2‐ethanedithiol ( Gel‐2 ), to yield cross‐linked and water‐swellable hydrogels in a one‐pot method. This protocol for the fabrication of PPG hydrogels exhibits promising advantages over prior methods including a short reaction time, mass‐production, easy separation, and high yield. A series of heavy metal ions were employed to test the adsorptive properties of the hydrogels. Gel‐2 shows better adsorption capacity than Gel‐1 for all the metal ions and the metal ions adsorption efficiency of the two types of hydrogels is in the order of Fe(III) > Pb(II) > Cd(II) > Zn(II) > Cu(II) > Ni(II) > Co(II) > Hg(II). The amounts of metal ions adsorbed increases with metal ion concentration and hydrogel dosage, but decreases with temperature. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40610.     

Adsorption properties of poly(acrylaminophosphonic-carboxyl-hydrazide)type chelating fiber for heavy metal ions

In this article, the adsorption properties of poly(acrylaminophosphonic-carboxyl-hydrazide) chelating fibers for Cu(II), Cd(II), Co(II), Mn(II), Pb(II), Zn(II), Ni(II), and Cr(III) are investigated by a batch technique. Based on the research results of binding capacity, adsorption isotherm, effect of pH value on sorption, and adsorption kinetics experiments, it is shown that the poly(acrylaminophosphonic-carboxyl-hydrazide) chelating fibers have higher binding capacities and good adsorption kinetic properties for heavy metal ions. The sorption of the metal ions on the chelating fibers is strongly dependent on the equilibrium pH value of the solution. The adsorption isotherms of Cu(II) and Cd(II) on the chelating fiber exhibit a Langmuir-type equation. The adsorbed Cu(II), Cd(II), Zn(II), and Pb(II) could be eluted by diluted nitric acid. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 70: 7–14, 1998     

Removal of lead (II) and cadmium (II) from aqueous solutions using spent Agaricus bisporus

The sorption of Pb and Cd from aqueous solutions by spent Agaricus bisporus was investigated. The effects of contact time, pH, ionic medium, initial metal concentration, other metal ions presence and ligands were studied in batch experiments at 25°C. Maximum sorption for both metals was found to occur at an initial pH of around 5.5. The equilibrium process was well described by the Langmuir isotherm model, with maximum sorption capacities of 0.2345 and 0.1273 mmol g^?1 for Pb and Cd respectively. Kinetic data followed the pseudo‐second‐order kinetic model. The presence of NaCl and NaClO₄ caused a reduction in Cd sorption, while Pb sorption was not remarkably affected. The presence of other metals did not affect Pb removal, while the Cd removal was much reduced. HCl or EDTA solutions were able to desorb Cd from the spent Agaricus bisporus (SAB) completely, while an approximately 60% and 15% desorption yield was obtained for Pb when HCl 0.01 mol L^?1 or EDTA 0.001 mol L^?1 were used, respectively. The results of FTIR, SEM and EDX analysis indicated that other mechanisms, such as surface complexation and electrostatic interactions, must be involved in the metal sorption in addition to ion exchange. © 2012 Canadian Society for Chemical Engineering     

添加剂对污泥焚烧过程中重金属迁移特性的影响

利用管式炉研究了Cl、S、P对重金属迁移特性的影响,研究结果表明：C促进了重金属Cd、Pb、Zn、Cu的挥发,而对重金属Ni、Cr的挥发特性影响不大;S对重金属的挥发特性影响不大,在一定程度上抑制霞金属Zn、Cd、Ni的挥发,而对重金属Pb则促进其挥发;P对不同重金属的挥发特性影响不同,随着P含量的增加,重金属Cr和Ni的挥发的挥发率逐渐增大,而重金属Cd、Pb和Zn的挥发率逐渐降低。     

Distribution of Heavy Metals in the Marine Sediments of Various Sites in Karaichalli Island,Tuticorin, Gulf of Mannar,India

The study of heavy metals in the sediments of coral islands is significant in understanding the distribution levels and the cause of anthropogenic impacts along the marine environment. A large number of heavy metals is discharged through domestic and industrial effluents along the coastal area of the southeast coast of India. In this work the sediments from Karaichalli island of Tuticorin were collected and the samples subjected to a total digestion technique and major and trace elements concentration estimated. To interpret and assess the contamination status for heavy metals in sediments, four metal pollution indices were assessed using a enrichment factor, a geo-accumulation index, contamination factor and pollution load index. The results were treated with SPSS 16.0 software for statistical analysis like Correlation matrix and Principal component analysis. The average metal accumulation levels in coral samples of the study area is in the following order: Fe > Mn > Zn > Cu > Ni > Pb > Cr > Cd > As > Co.

     

粒径对餐厨沼渣热解制备生物炭中磷和重金属的影响

以3种粒径餐厨沼渣为原料,在600℃下热解制备生物炭,研究粒径对沼渣（BR）及生物炭（BRC）中磷和重金属的影响,并采用TCLP浸出毒性和重金属潜在生态风险评估对其安全性进行系统研究。结果表明：BR及BRC中的磷主要以酸溶态磷（HCl-P）为主,残渣态磷（Res-P）次之,其余磷形态含量较低,总磷含量均呈现出随粒径增大而降低的趋势。热解促进H₂O-P、NaHCO₃-P和NaOH-P向HCl-P和Res-P转化。随着粒径的增大,BR中Cu、Zn总量增加,Cr减少,BRC中的Cr、As总量增加,Zn、Pb减少。并且BR中Cr、Zn、Pb和As中可氧化态和残渣态F3+F4随粒径增大而减少;BRC中Cr、Pb、As中F3+F4随粒径增大而减少,而Cu、Zn、Cd与之相反。TCLP浸出毒性和重金属潜在生态风险评估结果表明BR及BRC中重金属均属于低风险水平。     

Evaluation of some new hyperbranched polyesters as binding agents for heavy metals

Different generations of hydroxyl and carboxyl terminated hyperbranched polyesters were synthesised and used as heavy metals chelating compounds. The adsorptive capacity of the 3rd generation of the polyesters (G3‐OH, G3‐COOH) as well as that of nanoclay (Nanofil 116) for cadmium removal was determined through adsorption isotherm studies. The highest metal ion removal capacity was observed for G3‐COOH sample. The extent of binding (EOB) values of various generations of hyperbranched polyesters having the same core structure, but different terminal groups, indicated that, irrespective of the type of terminal group, the higher generations are more effective than the lower ones. EOB data can be adequately described by a bidentate coordination model for carboxyl terminated polyesters [each Cd(II) ion coordinates with two carboxyl groups] and tetradentate coordination model for hydroxyl terminated polyesters [1Cd(II)/4OH]. The EOB and selectivity properties of all prepared polyesters towards the heavy metal ions Cd(II), Cu(II), and Pb(II), were investigated under competitive condition. The results showed that the carboxyl terminated polymers exhibit higher binding capacities than those of hydroxyl terminated ones and the selectivity follows the order: Cu(II) > Cd(II) > Pb(II) for all polymer samples, irrespective of the type of terminal group. © 2011 Canadian Society for Chemical Engineering     

利用响应面法优化皂角苷浸提飞灰中重金属的处理条件

通过响应面法对皂角苷浸提飞灰中Cu、Zn、Pb和Cd 4种重金属的实验条件进行优化,选取pH、皂角苷浓度、离子强度、温度、时间和固液比6个因素进行中心组合设计,使用design-expert8.0软件进行数据拟合,建立了Cu、Zn、Pb和Cd去除总量的工艺数学模型,通过方差分析得到6个因素对浸提液中4种重金属去除总量的主效应关系为： pH>固液比>离子强度>皂角苷浓度>温度>时间。对重金属去除总量数据进行design-expert8.0软件优化,得到皂角苷浓度为41.2g·L^-1、时间为13.54 h、离子强度为0.64 mol·L^-1、pH为2、固液比为1%和温度为23.4℃时,重金属总去除量达最大值,Cu、Zn、Pb和Cd的去除率分别达到55.12%、6.20%、17.80%和78.11%。     

Preparation and characterization of magnetic polymethylmethacrylate microbeads carrying ethylene diamine for removal of Cu(II), Cd(II), Pb(II), and Hg(II) from aqueous solutions

Magnetic polymethylmethacrylate (mPMMA) microbeads carrying ethylene diamine (EDA) were prepared for the removal of heavy metal ions (i.e., copper, lead, cadmium, and mercury) from aqueous solutions containing different amount of these ions (5–700 mg/L) and at different pH values (2.0–8.0). Adsorption of heavy metal ions on the unmodified mPMMA microbeads was very low (3.6 μmol/g for Cu(II), 4.2 μmol/g for Pb(II), 4.6 μmol/g for Cd(II), and 2.9 μmol/g for Hg(II)). EDA‐incorporation significantly increased the heavy metal adsorption (201 μmol/g for Cu(II), 186 μmol/g for Pb(II), 162 μmol/g for Cd(II), and 150 μmol/g for Hg(II)). Competitive adsorption capacities (in the case of adsorption from mixture) were determined to be 79.8 μmol/g for Cu(II), 58.7 μmol/g for Pb(II), 52.4 μmol/g for Cd(II), and 45.3 μmol/g for Hg(II). The observed affinity order in adsorption was found to be Cu(II) > Pb(II) > Cd(II) > Hg(II) for both under noncompetitive and competitive conditions. The adsorption of heavy metal ions increased with increasing pH and reached a plateau value at around pH 5.0. The optimal pH range for heavy‐metal removal was shown to be from 5.0 to 8.0. Desorption of heavy‐metal ions was achieved using 0.1 M HNO₃. The maximum elution value was as high as 98%. These microbeads are suitable for repeated use for more than five adsorption‐desorption cycles without considerable loss of adsorption capacity. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 81–89, 2000     

Removal of lead,cadmium and zinc from aqueous solutions by precipitation with sodium Di‐(n‐octyl) phosphinate

Sodium di‐(n‐octyl) phosphinate (NaL) was used as a precipitating agent to remove heavy metals from aqueous nitrate solutions. Cadmium, zinc and mixtures of lead, cadmium and zinc were precipitated in the form of PbL_2(s), CdL_2(s), and ZnL_2(s). Lowering the pH of the feed solution reduced the removal of the metals as some of the phosphinate precipitated in the acid form as HL_(S). The removal of lead, cadmium, and zinc, from a solution containing the three metals gave a selectivity in the order Zn > Pb > Cd. Predictions of an equilibrium‐constant model, using measured solubility products of the precipitates and literature values of stability constants, gave metal removals, loss of precipitating agent, and equilibrium pH in good agreement with measured values.     

Sorption of Pb(II), Cd(II) and Zn(II) by iminodiacetate chelating resins in non-competitive and competitive conditions

Two chelating resins (CRs) bearing iminodiacetate (IDA) groups derived from acrylonitrile - divinylbenzene (AN-DVB) copolymers having 10 and 15 wt.% nominal cross-linking degrees and a high mobility of the functional groups caused by the presence of a longer spacer between the matrix and the IDA groups were synthesized and tested as sorbents for heavy metal ions like: Pb(II), Cd(II) and Zn(II) from aqueous solutions by batch and column techniques. Experimental data obtained from batch equilibrium tests have been analyzed by two isotherm models: Freundlich and Langmuir. The overall adsorption tendency of CRs toward Pb(II), Cd(II) and Zn(II), under non-competitive conditions, followed the order: Cd(II) > Pb(II) > Zn(II). Selectivity studies were performed in ternary mixture of Pb(II), Cd(II) and Zn(II) to check if the synthesized CRs can be useful for selective separation of heavy metal cations. The results revealed that the CRs with IDA groups exhibited high selectivity toward Pb(II), both in batch and column techniques. Regeneration of the resins was achieved using 0.1 M HCl solution.     

Determination of the competitive adsorption of heavy metal ions on poly(n‐vinyl‐2‐pyrrolidone/acrylic acid) hydrogels by differential pulse polarography

Poly(N‐vinyl‐2‐pyrrolidone) and poly(N‐vinyl‐2‐pyrrolidone/acrylic acid) hydrogels were prepared by gamma irradiation for the removal of heavy metal ions (i.e., lead, copper, zinc, and cadmium) from aqueous solutions containing different amounts of these ions (2.5–10 mg/L) and at different pH values (1–13). The observed affinity order in adsorption of these metal ions on the hydrogels was Zn(II) > Pb(II) > Cu(II) > Cd(II) under competitive conditions. The optimal pH range for the heavy metal ions was from 7 to 9. The adsorption of the heavy metal ions decreased with increasing temperature in both water and synthetic seawater conditions. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2013–2018, 2003     

改性玉米淀粉对重金属捕集性能的研究

研究了二硫代氨基甲酸改性玉米淀粉(DTCS)对单一重金属溶液中重金属离子的捕集作用,考察了影响其捕集作用的因素,包括重金属种类、pH、温度、混凝时间、无机离子的干扰等,确定了合适的应用条件.结果表明,在单一重金属离子浓度为1.0×10-3 mol/L的溶液中,DTCS对重金属离子捕集的选择性:Cu2 ＞Pb2 ＞Cd2 ＞Zn2 ＞Ni2 ,去除率分别为99.91%、99.88%、87.36%、85.17%、66.36%,且K 、Ca2 等无机离子对其去除效果影响不大.