有机配体对膨润土负载纳米零价铁还原Cr(Ⅵ)的影响

六价铬〔Cr(Ⅵ)〕因具有剧毒性和致癌性而被广泛关注.以Fe(Ⅲ)与NaBH4反应制得负载型的纳米铁(B-NZVI),并对该材料做了TEM和AAS的表征;深入考察B-NZVI去除Cr(Ⅵ)的动力学规律,以及草酸、柠檬酸、草酸钠、柠檬酸钠等有机配体对膨润土负载纳米零价铁还原Cr(Ⅵ)去除速率的影响,并对其影响机理进行初步探讨.结果表明,膨润土负载纳米零价铁对Cr(Ⅵ)的去除行为符合Langmuir-Hinshelwood模型,其kobs为0.011 97 min-1;草酸、柠檬酸、草酸钠和EDTA可促进B-NZVI对Cr(Ⅵ)的还原去除作用;柠檬酸钠则起到抑制作用.

Influence of Various Organic Ligands on the Removal of Cr(Ⅵ)by Bentonite Supported Nanoscale Zero-Valent Iron

Cr(Ⅵ) is drawing widespread concern due to its toxicity and carcinogenicity.In this work,the removal of Cr(Ⅵ) by bentonite-supported nanoscale zero-valent iron(B-NEVI) was investigated.B-NEVI was synthesized by the reduction of Fe(Ⅲ) with NaBH4,and characterized by TEM and AAS.The removal kinetics and the influence on the removal rate of various organic ligands,including oxalic acid,citric acid,sodium citrate and sodium oxalate,were investigated in depth,and their influencing mechanisms were preliminarily discussed.The results indicated that the kinetic experimental data fitted the Langmuir-Hinshelwood equation with kobs of 0.01197 min-1,and that oxalic acid,citric acid,sodium oxalate and EDTA accelerated the removal of Cr(Ⅵ) while sodium citrate retarded the removal.