零价铁/炭去除水中的As(Ⅴ)

ARSENATE REMOVAL BY ZERO VALENT IRON/CARBON COUPLES

将零价铁(ZVI)分别与活性炭,石墨,碳纤维和碳纳米管按照质量比10∶1组成电偶腐蚀体系用于水中As(V)去除,结果显示零价铁/活性炭组合的去除效果略高于其它组合.XRD测试表明,组合体系中零价铁腐蚀的主要反应产物为纤铁矿,磁铁矿/磁赤铁矿.对零价铁阳极/活性炭阴极不同质量比例的研究表明,1∶1时效果最佳.随着电解质浓度升高,As(V)去除效率增大,在0.03mol.l-1NaCl电解质条件下,初始As(V)为5mg.l-1时,零价铁/活性炭组合与As(V)反应2.5h后,As(V)的去除率达到100%.SO24-,NO3-,CO32-,SiO44-,PO43-等共存阴离子,以及腐殖酸对零价铁/活性炭组合去除As(V)影响的研究结果表明,CO32-,PO43-和腐殖酸对As(V)的去除效率影响不大,SiO44-具有一定的抑制作用,相反,SO42-和NO3-表现为明显的促进作用.

Batch tests were performed to evaluate arsenate removal efficiency by using different galvanic couples consisting of zero valent iron （ZVI） and various carbon materials with a mass ratio of 10：1. Activated carbon （AC）,graphite,carbon fiber,and carbon nano-tube were used as anodes. The results showed that efficiency of ZVI/AC couple was slighly higher than that of others. X-ray diffraction patterns of corrosion products from serial ZVI/carbon couples after reaction with As（V） indicated lepidocrocite,magnetite and maghemite were the major minerals of ZVI reaction products. A mass ratio of 1：1 was found to be optimal for ZVI/AC couple. It was shown that with an increase of background electrolyte concentration,As（V） removal was more efficient. After 2.5 hours reaction,an removal efficiency of 100% was achieved,with initial As（V） concentration of 5 mg·l^-1 in 0.03 mol·l^-1 NaCl solution. The effect of inorganic anion competition on the kinetics of arsenate As（V）removal by ZVI/AC couple was tested. Phosphate,carbonate and humic acid showed little inhibition of As（V） removal,silicate caused some decrease in As（V） removal rate,while sulfate and nitrate significantly promoted the removal rate of As（V）.