Fe(Ⅲ)-(S,S)-乙二胺-N,N'-二琥珀酸体系中Cr(Ⅵ)的紫外光还原

Photoreduction of Cr(Ⅵ) with Fe(Ⅲ)-ethylenediamine-N,N'-disuccinic acid system

将易生物降解的天然螯合剂乙二胺-N,N’-二琥珀酸(EDDS)与Fe(Ⅲ)结合形成Fe(Ⅲ)-EDDS体系并用于处理水中Cr(Ⅵ).在紫外光照射下利用该体系对Cr(Ⅵ)进行光还原,考察了溶液p H值、Fe(Ⅲ)-EDDS和Cr(Ⅵ)的初始浓度对Cr(Ⅵ)去除率的影响.结果表明,UV/Fe(Ⅲ)-EDDS体系对Cr(Ⅵ)有光还原作用,且紫外光是反应进行的必要条件.在p H为3.0~8.0的范围内,反应顺利进行,且溶液的p H值越小,Cr(Ⅵ)的还原效果越好,去除率越高.Fe(Ⅲ)-EDDS浓度的增加对Cr(Ⅵ)还原有促进作用,Fe(Ⅲ)-EDDS浓度在0.10~0.30 mmol·L-1之间时,随着Fe(Ⅲ)-EDDS浓度的增大,Cr(Ⅵ)的还原率增大;当溶液中Fe(Ⅲ)-EDDS浓度不变,Cr(Ⅵ)浓度在5~20 mg·L-1之间时,Cr(Ⅵ)的去除率随其浓度的增加而降低.

In this paper,photoreduction of Cr( Ⅵ) using the complex between Fe( Ⅲ) and a readily biodegradable and strong complexing reagent ethylenediamine-N,N'-disuccinic acid( EDDS) was investigated. The experimental parameters such as solution p H, initial concentration of Fe( Ⅲ)-EDDS complex and Cr( Ⅵ) were systematically studied. The experimental results showed that UV irradiation is indispensable for the efficient removal of Cr( Ⅵ). Lower solution p H in the range of 2.0 ~ 8.0 favors the photoreduction of Cr( Ⅵ) in Fe( Ⅲ)-EDDS-UV system,and the removal rate of Cr( Ⅵ) was found to increase with increase in the concentration( 0. 10 ~ 0. 30 mmol·L-1) of Fe( Ⅲ)-EDDS complex photocatalyst. However,the photoreduction rate of Cr( Ⅵ) decreases with increasing initial concentration of Cr( Ⅵ)( 5 ~ 20 mg·L-1).