Performance and mechanism of Cr(Ⅵ)removal from wastewater by sustained-release nZVI-loaded activated carbon(nZVI-C)
Nanoscale zero-valent iron(nZVI)have advantages such as high pollutant removal efficiency,easy preparation,low cost,and environmental friendliness,and are widely used in the field of environmental remediation.Currently,the research focus on nZVI is to improve its drawbacks of easy aggregation and oxidation by modification,and enhance its remediation performance.This study combined the loading method and polymer coating modification method,and used activated carbon and non-toxic green polyaspartic acid(PASP)to achieve good stability and sustained-release effects for nZVI,which reduced nZVI aggregation,increasing specific surface area,prolonging reaction equilibrium time,and significantly increasing the removal of Cr(Ⅵ)in water.When the ratio of iron to carbon was 2∶1,the remediation performance of the composite material was 1.75 times that of the sum of nZVI alone and activated carbon alone,and the highest Cr(Ⅵ)remove rate could reach 99.91％.In the study,the optimal preparation conditions of the composite were screened by the orthogonal experiments,and the effects of C-PASP-nZVI dosage,pollutant concentration and pH on the remediation effect of Cr(Ⅵ)containing wastewater were analyzed.The adsorption kinetics of Cr(Ⅵ)on C-PASP-nZVI conformed to the Lagergren pseudo-second-order model,indicating that the removal process of Cr(Ⅵ)on the composite was dominated by chemical adsorption.The results of above study indicate that C-PASP-nZVI is a potential ideal material for the remediation of heavy metal-contaminated water bodies.
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