The effects of immobilization remediation of Cd-contaminated soils using sepiolite on soil pH, enzyme activities and microbial communities, TCLP-Cd （toxicity characteristic leaching procedure-Cd） concentration, and ...The effects of immobilization remediation of Cd-contaminated soils using sepiolite on soil pH, enzyme activities and microbial communities, TCLP-Cd （toxicity characteristic leaching procedure-Cd） concentration, and spinach （Spinacia oleracea） growth and Cd uptake and accumulation were investigated. Results showed that the addition of sepiolite could increase soil pH, while the TCLP-Cd concentration in soil was decreased with increasing sepiolite. The changes of soil enzyme activities and bacteria number indicated that a certain metabolic recovery occurred after the sepiolite treatments, and spinach shoot biomass increased by 58.5%-65.5% in comparison with the control group when the concentration of sepiolite was ~ 10 g/kg. However, the Cd concentrations in the shoots and roots of spinach decreased with an increase in the rate of sepiolite, experiencing 38.4%-59.1% and 12.6%--43.6% reduction, respectively, in contrast to the control. The results indicated that sepiolite has the potential for success on a field scale in reducing Cd entry into the food chain.展开更多
A polymeric hydroxyl ferric phosphate(PHFP)was prepared by using a byproduct of titanium dioxide containing ferrous sulfate and phosphates under alkaline condition.The PHFP was used to immobilize lead(Pb)and cadmium(C...A polymeric hydroxyl ferric phosphate(PHFP)was prepared by using a byproduct of titanium dioxide containing ferrous sulfate and phosphates under alkaline condition.The PHFP was used to immobilize lead(Pb)and cadmium(Cd)in soils.Fourier transform infrared spectra,X-ray diffraction were applied to revealing the characteristics of PHFP,and the modified Tessier sequential extraction and column leaching experiment with simulated acid rain were used to assess the effectiveness of immobilization of Cd and Pb in soils by PHFP.The results showed that PHFP was indeed a polymer with complicated OH-Fe-P structure and consisted of Fe6(OH)5(H2O)4(PO4)4(H2O)2and Fe25(PO4)14(OH)24.Moreover,the removal rates of DTPA-extractable Cd and Pb in soils reached up to33%and45%,and the water-soluble Cd and Pb decreased by56%and58%,respectively,when PHFP was added in soils at4%dosage.In addition,the immobilization of Cd and Pb contributed to transforming water soluble,exchangeable and carbonate-bonded fractions to Fe and Mn oxides-bonded,organic-bonded and residual fractions.Under leaching with simulated acid rain,Cd and Pb release amount in PHFP amended soil declined by53%and52%,respectively,as compared with non-treated soil.The result implied that PHFP had a potential application for the remediation of Cd-and Pb-contaminated soils.展开更多
基金supported by the National Natural Science Foundation of China (No. 2117706840901154+2 种基金21107056)the Program for Distinguished Scholar and Innovative Team of MOA (No. 2012-jcrc-xym)the Central Public Research Institutes Basic Funds for Research and Development (No.2011-szjj-syb)
文摘The effects of immobilization remediation of Cd-contaminated soils using sepiolite on soil pH, enzyme activities and microbial communities, TCLP-Cd （toxicity characteristic leaching procedure-Cd） concentration, and spinach （Spinacia oleracea） growth and Cd uptake and accumulation were investigated. Results showed that the addition of sepiolite could increase soil pH, while the TCLP-Cd concentration in soil was decreased with increasing sepiolite. The changes of soil enzyme activities and bacteria number indicated that a certain metabolic recovery occurred after the sepiolite treatments, and spinach shoot biomass increased by 58.5%-65.5% in comparison with the control group when the concentration of sepiolite was ~ 10 g/kg. However, the Cd concentrations in the shoots and roots of spinach decreased with an increase in the rate of sepiolite, experiencing 38.4%-59.1% and 12.6%--43.6% reduction, respectively, in contrast to the control. The results indicated that sepiolite has the potential for success on a field scale in reducing Cd entry into the food chain.
基金Project(2012GS430203)supported by Science and Technology Program for Public Wellbeing,ChinaProject(51504299)supported by the National Natural Science Foundation of ChinaProject(2015WK3016)supported by Science and Technology Program of Hunan Province,China
文摘A polymeric hydroxyl ferric phosphate(PHFP)was prepared by using a byproduct of titanium dioxide containing ferrous sulfate and phosphates under alkaline condition.The PHFP was used to immobilize lead(Pb)and cadmium(Cd)in soils.Fourier transform infrared spectra,X-ray diffraction were applied to revealing the characteristics of PHFP,and the modified Tessier sequential extraction and column leaching experiment with simulated acid rain were used to assess the effectiveness of immobilization of Cd and Pb in soils by PHFP.The results showed that PHFP was indeed a polymer with complicated OH-Fe-P structure and consisted of Fe6(OH)5(H2O)4(PO4)4(H2O)2and Fe25(PO4)14(OH)24.Moreover,the removal rates of DTPA-extractable Cd and Pb in soils reached up to33%and45%,and the water-soluble Cd and Pb decreased by56%and58%,respectively,when PHFP was added in soils at4%dosage.In addition,the immobilization of Cd and Pb contributed to transforming water soluble,exchangeable and carbonate-bonded fractions to Fe and Mn oxides-bonded,organic-bonded and residual fractions.Under leaching with simulated acid rain,Cd and Pb release amount in PHFP amended soil declined by53%and52%,respectively,as compared with non-treated soil.The result implied that PHFP had a potential application for the remediation of Cd-and Pb-contaminated soils.
