Fe(Ⅲ)强化单宁酸原位修复Cr(Ⅵ)污染含水层反应机理及效能

研究Fe(Ⅲ)对单宁酸(TA)原位修复含水层Cr(Ⅵ)污染的反应机理及效能. 结果表明，Fe(Ⅲ)通过与单宁酸配合可有效提高单宁酸对Cr(Ⅵ)污染含水层的修复效率. 单宁酸分子中邻苯三酚结构中两个相邻的酚羟基与Fe(Ⅲ)配合并提供电子，因此修复1 mol Cr(Ⅵ)至少需要9 mol单宁酸；若使Fe(Ⅲ)达到最好的强化效果， 则要求n（TA）∶n（Fe(Ⅲ)）=3∶5， 此时单宁酸-Fe(Ⅲ)结构最稳定， 储存容量最大. 在Cr(Ⅵ)污染被修复后， Fe(Ⅲ)在单宁酸的作用下形成稳定的FeOOH， 对Cr(Ⅲ)进行吸附并形成共沉淀， 从而达到去除总Cr的目的. 

Reaction Mechanism and Efficiency of in situ Remediation of Cr(Ⅵ) Contaminated Aquifer by Fe (Ⅲ) Enhanced Tannic Acid

We studied reaction mechanism and efficiency of in situ remediation of Cr(Ⅵ) contaminated aquifer by Fe(Ⅲ)  enhanced tannic acid (TA). The results show that Fe(Ⅲ) can effectively improve the remediation efficiency of tannic acid to Cr(Ⅵ) contaminated aquifer by complexing with tannic acid. The two adjacent phenolic hydroxyl groups of pyrogallol structure in tannic acid molecule combine with Fe(Ⅲ) to prvide electrons,  so at least 9 mol tannic acid is needed to repair 1 mol Cr(Ⅵ). For the best strengthening effect of Fe(Ⅲ),  n（TA）∶n（Fe(Ⅲ)）=3∶5. At this time,  the tannic acid/Fe(Ⅲ) structure is the most stable and the storage capacity reaches the maximum.  After Cr(Ⅵ) pollution is repaired,  Fe(Ⅲ)  forms stable FeOOH under the action of tannic acid to adsorb Cr(Ⅲ) and form coprecipitation,  so as to achieve the purpose of remving total chromium.