首页|Efficient remediation of different concentrations of Cr-contaminated soils by nano zero-valent iron modified with carboxymethyl cellulose and biochar
Efficient remediation of different concentrations of Cr-contaminated soils by nano zero-valent iron modified with carboxymethyl cellulose and biochar
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Efficient remediation of different concentrations of Cr-contaminated soils by nano zero-valent iron modified with carboxymethyl cellulose and biochar
Nano zero-valent iron(nZVI)is widely used in soil remediation due to its high reactivity.However,the easy agglomeration,poor antioxidant ability and passivation layer of Fe-Cr coprecipitates of nZVI have limited its application scale in Cr-contaminated soil remedia-tion,especially in high concentration of Cr-contaminated soil.Herein,we found that the carboxymethyl cellulose on nZVI particles could increase the zeta potential value of soil and change the phase of nZVI.Along with the presence of biochar,97.0%and 96.6%Cr im-mobilization efficiency through CMC-nZVI/BC were respectively achieved in high and low concentrations of Cr-contaminated soils after 90-days remediation.In addition,the immobi-lization efficiency of Cr(Ⅵ)only decreased by 5.1%through CMC-nZVI/BC treatment after 10 weeks aging in air,attributing to the strong antioxidation ability.As for the surrounding Cr-contaminated groundwater,the Cr(Ⅵ)removal capacity of CMC-nZVI/BC was evaluated un-der different reaction conditions through column experiments and COMSOL Multiphysics.CMC-nZVI/BC could efficiently remove 85%of Cr(Ⅵ)in about 400 hr when the initial Cr(Ⅵ)concentration was 40 mg/L and the flow rate was 0.5 mL/min.This study demonstrates that uniformly dispersed CMC-nZVI/BC has an excellent remediation effect on different concen-trations of Cr-contaminated soils.