Sorption Capacity For Cu Research Articles

Copper Sorption Behavior of Selected Soils of the Oasis in the Middle Reaches of Heihe River Basin, China

The mobility and bioavailability of copper (Cu) depends on the Cu sorption capacity of soil and also on the chemical form of Cu in soils. Laboratory batch experiments were carried out to study the sorption and distribution of Cu in nine soils differing in their physicochemical properties from the oasis in the middle reaches of Heihe river basin, China: desert soil (S-1), agricultural soils (S-2, S-3, S-8, and S-9), marshland soil (S-4), and hungriness shrub soils (S-5 and S-6). Copper sorption behavior was studied using the sorption isotherm and sequential extraction procedure. In general, the sorption capacity for Cu decreased in the order: S-4 > S-9 > S-2 > S-8 > S-3 > S-6 > S-5 > S-7 > S-1. The correlation results suggest that soils with higher CEC, silt, clay, CaCO3, and organic matter will retain Cu more strongly and in greater amounts than soils that are sandy with lower CEC, CaCO3, and organic matter. pH is not an important impact factor to Cu sorption in experimental soil samples because pH in soils used in this study had a narrow range. The distribution of sorbed Cu varied between nine soils studied and depended on both soil properties and initial added Cu concentration. There are significant differences in the distribution of Cu in each soil with the increase of initial Cu concentration. The predominance of Cu associated with the available fraction, which was over 50% of the total sorbed Cu in most cases, indicates that the change of geochemical conditions might promote the release of Cu back into soil solution thus impacting organisms in the soils. The added Cu has also the tendencies to locate in the residual fraction, which was larger than 5% of the total amount extracted from the four fractions in most soils.

Utilization of barley straws as biosorbents for Cu 2+ and Pb 2+ ions

The potential to remove Cu 2+ and Pb 2+ ion from aqueous solutions through biosorption using barley straw (BS) was investigated in batch experiments. The main parameters influencing Cu 2+ and Pb 2+ ion sorption on BS were: initial metal ion concentration, amount of adsorbent, contact time and pH value of solution. The influences of initial Cu 2+ and Pb 2+ ion concentration (0.1–1 mM), pH (2–9), contact time (10–240 min) and adsorbent amount (0.1–1.0 g) have been reported. Equilibrium isotherms have been measured and modelled. The percent adsorption of Cu 2+ and Pb 2+ ions increased with an increase in pH and dosage of treated BS. The biosorptive capacity of the BS was dependent on the pH of Cu 2+ and Pb 2+ ion solution. Adsorption of Cu 2+ and Pb 2+ ion was in all cases pH dependent showing a maximum at equilibrium pH value at 6.0. The equilibrium sorption capacities of Cu 2+ and Pb 2+ after 2 h were 4.64 mg/g and 23.20 mg/g for BS, respectively. The adsorption data fit well with the Langmuir isotherm model and the experimental result inferred that complexation on surface, adsorption (chemisorption) and ion exchange is one of the major adsorption mechanisms for binding Cu 2+ and Pb 2+ ion to the sorbents.

Metal desorption from copper(II)/nickel(II)-spiked kaolin as a soil component using plant-derived saponin biosurfactant

This study reports experimental measurements on the washing ability of quillaja saponin biosurfactant in kaolin suspensions, which were presorbed with the binary heavy metals of Cu(II) and Ni(II). A synthetic surfactant (SDS) and chelating agent (EDTA) were also evaluated for comparison studies. The sorption capacity for Cu(II) and Ni(II) onto kaolin were measured through the variation in pH and initial metal ion concentration. Much attention has been paid to understanding the micelle-forming properties of biosurfactant solution and its interaction with metals at the clay–water interface so washing strategies can then seek to achieve the ideal capacities of saponin biosurfactant for desorbing heavy metals from kaolin clays. The desorption of Cu(II) and Ni(II) from kaolin were examined as a function of pH, saponin concentration, temperature, time and mass/volume ratio of kaolin suspension. Because the saponin successfully competes with the kaolin clay for complexing with the metal ions by the Lewis acid–base interaction induced by pH, structure size, or charge of surfactant solution, the highest desorption improvements by 2000 mg/l of saponin were gained at 20 g/l kaolin suspension and pH 5–8, in which a single washing at room temperature could remove ∼83% of the copper and ∼85% of the nickel from kaolin containing 0.45 mg copper/g kaolin and 0.14 mg nickel/g kaolin. These results were interpreted as showing the action of a three-step micellar washing mechanism on the desorption efficiencies for Cu(II) and Ni(II). It is then pointed out quillaja saponin may be applied as a useful biosurfactant for the removal of heavy metals in contaminated clays or soils.

Surface modification of macroporous glycidyl methacrylate based copolymers for selective sorption of heavy metals

Two samples of macroporous poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate), poly(GMA-co-EGDMA), were synthesized by suspension copolymerization and modified with amines. Initial poly(GMA-co-EGDMA), and the samples modified with ethylene diamine [poly(GMA-co-EGDMA)-en], diethylene triamine [poly(GMA-co-EGDMA)-deta] and triethylene tetramine [poly(GMA-co-EGDMA)-teta], were characterized by mercury porosimetry, FTIR spectroscopy and elemental analysis. The most pronounced increase of specific surface area (75%) was observed for poly(GMA-co-EGDMA)-teta sample with smaller particles (D < 150 μm). The Cu(II) sorption was rapid, depending on porosity of amino-functionalized samples and ligand type. For poly(GMA-co-EGDMA)-deta and poly(GMA-co-EGDMA)-teta sorption half time required to reach 50% of total sorption capacity, t 1/2, were around 3 min. Sorption capacities for Cu(II), Co(II), Cd(II) and Ni(II) as well as for Cr(VI), Co(II), Cd(II) and Ni(II) ions were determined under competitive conditions as a function of pH, ligand type and porosity at room temperature. The results indicate selectivity of poly(GMA-co-EGDMA)-deta for Cu(II) over Cd(II) of 3:1 and for Cu(II) over Ni(II) and Co(II) of 6:1. The decrease in particle size of poly(GMA-co-EGDMA)-teta caused the increase of sorption capacities for all metal ions. At pH 1.8 the selectivity of poly(GMA-co-EGDMA)-teta with smaller particles for Cr(VI) over Ni(II), Co(II) and Cd(II) ions was 8.5:1.

Sorption and Fractionation of Copper in Soil at a Sewage Irrigation Farm in Australia

Copper (Cu) is an important heavy metal to be considered in soil contamination, because high concentrations of copper in soil produce toxic effects and may accumulate in plant tissues. In Australia's oldest sewage irrigation farm, located in Werribee, Victoria, soil in the land filtration area is contaminated by Cu. However, Cu content in herbage tissues is in the normal range and has been trending downward since 1979. Therefore, studies on the sorption capacity and sequential extraction of Cu in soil at the Werribee Farm is of significance, not only for better understanding the mechanism of transport, chemical processes, and plant uptake of Cu, but also in providing information for the practical management of sewage farm soils. Methods of combining sorption isotherms with sequential extraction procedures were adopted, and the results showed that the soil in the land filtration area at Werribee Farm has a high sorption capacity for Cu, and distribution coefficients, Kf of Cu, were 629 L kg−1 in surface soils (0–20 cm) and 335 L kg−1 in subsurface soils (20–40 cm). The sequential extraction fractions demonstrate that exchangeable and carbonate fractions are very low, only comprising 3.49 to 5.49% of total copper. The other fractions are also discussed. This characteristic of Cu in soil is related to the low concentration of Cu in plant tissues.

Factors Affecting the Removal of Selected Heavy Metals using a Polymer Immobilised Sphagnum Moss as a Biosorbent

A hydrophilic polyurethane foam was used to immobilise dried sphagnum moss as a polymer/biomass matrix. This was then tested for its ability to remove Cu(II), Zn(II) and Pb(II) from aqueous solution. Further selected experiments using copper looked at factors which it was thought might affect the performance of the biosorbent. The optimum pH for Cu(II) and Zn(II) sorption was found to be in the range 6 - 7, whilst Pb(II) showed a more uniform sorption profile over the pH range 3 – 8. At pH values above 8 there was significant leaching of organic components from the immobilisation matrix. The immobilised biomass maintained around 90% of its sorption capacity over 10 repetitive cycles of sorption/desorption using HCl as a desorbent with typically > 95% metal ion recovery from each cycle. There were no marked differences in the maximum sorption capacities for Cu(II) using different biomass particle sizes in the immobilisation matrix, but the affinity of the immobilised biomass for Cu(II) decreased with increasing particle size. Alkali and alkaline-earth metal ions did not affect the heavy metal biosorption, but aluminium ion had a significant influence and itself could be adsorbed to a large extent. Acetic acid, urea, and carrageenan did not affect the maximum biosorption capacity of Cu(II), but carrageenan significantly reduced the affinity of biomass to metal ions probably as a result of its own biosorptive properties.

Equilibrium sorption isotherms for of Cu 2+ on rice bran

A new sorbent (rice bran) for removing Cu 2+ from aqueous solution has been investigated. The experimental results were fitted to the Langmuir, Freundlich, Temkin and Redlich–Peterson isotherms to obtain the characteristic parameters of each model. Langmuir, Temkin and Redlich–Peterson isotherms were found to represent the measured sorption data. The maximum sorption capacity of Cu 2+ on the rice bran was 33.58 mg/g according to the evaluation of using the Langmuir equation.

Metal sorption on macroporous poly(GMA-co-EGDMA) modified with ethylene diamine

Two samples of macroporous crosslinked poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate), poly(GMA-co-EGDMA), with different porosity parameters were synthesized by suspension copolymerization and modified by ring-opening reaction of the pendant epoxy groups with ethylene diamine (EDA). The samples were characterized by mercury porosimetry, FT-IR spectroscopy and elemental analysis. The sorption rate of the modified copolymer, poly(GMA-co-EGDMA)-en for Cu(II) ions determined under non-competitive conditions was relatively rapid, i.e. the maximum capacity was reached within 30 min. Batch sorption capacities for Cu(II), Fe(II), Mn(II), Cd(II), Zn(II), Pb(II), Cr(III) and Pt(IV) ions were determined under non-competitive conditions in the pH range 1.25–5.5 at room temperature. The maximum sorption capacities of poly(GMA-co-EGDMA)-en under non-competitive conditions were 1.30 mmol/g for Pt(IV) at pH 5.5, 1.10 mmol/g for Cu(II) at pH 5.5, 1.06 mmol/g for Pb(II) at pH 1.25 and 0.67 mmol/g for Cd(II) ions at pH 5.5. The selectivity of poly(GMA-co-EGDMA)-en towards Cu(II), Co(II), Ni(II), Pb(II) and Pt(IV) ions was investigated under competitive conditions. Poly(GMA-co-EGDMA)-en showed high selectivity for Pt(IV) over Cu(II), Co(II), Ni(II) and Pb(II) ions at pH 2.1. At pH 5.5, the metal sorption capacities of poly(GMA-co-EGDMA)-en decreased in the order: Cu(II) > Co(II) > Pt(IV) ≈ Ni(II) > Pb(II). Regeneration of the Cu(II), Ni(II) and Pb(II) loaded poly(GMA-co-EGDMA)-en with 2 M H 2SO 4 showed that the polymer can be reused in several sorption/desorption cycles.

Sorption and transport of metals in preferential flow paths and soil matrix after the addition of wood ash

SummaryAs a consequence of heterogeneous transport in soils, only a small part of the soil might be responsible for sorbing incoming elements. After staining preferential flow paths in forested Dystric Cambisol with a colour dye, we sampled soil material from the flow paths and from the soil matrix. We measured chemical properties and sorption isotherms of these two flow regions and estimated the significance of preferential flow paths for the transport of solutes leached from wood ash applied at the surface. In the A horizon (0–9 cm depth), the cation exchange capacity of the flow paths was 83.8 mmolc kg−1, while that of the soil matrix was only 74.6 mmolc kg−1. The base saturation was 42% and soil organic matter content was 41% larger in flow paths than in the soil matrix. The sorption capacity for Cu was also larger than in the matrix, whereas the sorption capacity for Sr was similar in both flow regions. The impact of the addition of 8 t wood ash ha−1 on soil chemical properties was restricted mainly to the flow paths in the uppermost 20 cm of the soil; it was negligible in the matrix and at greater depths. Concentrations of exchangeable Ca in the flow paths increased nearly 10‐fold during the 6 months following the addition of the wood ash, and those of organically bound Pb by 50%. The opposite effect was found for exchangeable Al. Our results show that only part of the whole soil volume, approximately 50% of 0–20 cm in our study, is involved in transporting and sorbing the elements applied with the wood ash or as tracers. Such differences must be considered when calculating the maximal impact of any addition of fertilizer, wood ash, or liming agent.

Screening of waste biomass from Saccharomyces cerevisiae, Aspergillus oryzae and Bacillus lentus fermentations for removal of Cu, Zn and Cd by biosorption.

Three by-products of fermentations containing Bacillus lentus, Aspergillus oryzae or Saccharomyces cerevisiae biomass were tested for the capacity to absorb Cu, Cd and Zn. The composition of the three biomasses was first determined and showed high contents of ashes in both B. lentus and A. oryzae biomass and high amounts of lipids in the bacterial biomass. Metal ion binding experiments were performed by contact of 0.1 g of biomass (protonated for all the metal tests and not protonated only for the Cd test) with 50 ml of solutions containing each of the metals in the concentration range from 10 to 500 mg/ml, at pH 4.5, 3.5 and 2.5. The final metal ion concentrations were determined using a plasma absorption spectrometer, and the metal removal levels for isotherm plots were determined using the Langmuir model. The results showed that B. lentus protonated biomass had the best sorption capacity for Cu and Cd, followed by protonated A. oryzae and S. cerevisiae biomass. The sorption of Zn was low for all tested biomasses, as also was the binding of all metals at acidic pH (2.5 and 3.5). A significant increase in Cd sorption was obtained using non-protonated biomass from B. lentus and A. oryzae.

Sorption behavior of copper, zinc, and cadmium in response to simulated changes in soil properties

Environmental changes and management practices which alter soil properties may affect the capacity of soils to sorb trace metals, such as copper (Cu), zinc (Zn), and cadmium (Cd), and thus influence the bioavailability and leach ability of the metals. Two agricultural soils were treated to partially oxidize organic matter and to decrease soil pH for evaluating the effects of acidification and organic matter oxidation on trace metal sorption onto soils. For the one soil with a pH value of 6.74 and organic carbon (C) content of 46.9 g‐kg‐1, loss of 11% of its organic matter reduced by 97, 72, and 62% the original sorption capacity for Cu, Zn, and Cd, respectively, while the corresponding values caused by acidifying the soil one pH‐unit were 32, 16, and 29%. For the another soil with a pH of 4.69 and organic C content of 16.3 g‐kg‐1, a decrease in pH by one unit resulted in a loss of 43, 21, and 52% of the sorption capacity for Cu, Zn, and Cd, respectively.