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三价铁介导紫外光催化氧化有机磷酸酯同步还原六价铬

2021-09-13李秋月陈欣冉黄开波梁佳豪陶雪琴党志卢桂宁

土木建筑与环境工程 2021年6期

李秋月 陈欣冉 黄开波 梁佳豪 陶雪琴 党志 卢桂宁

摘 要:有机磷酸酯(OPEs)阻燃剂与重金属铬是电子垃圾拆解区环境中常见的复合污染物。研究300 W汞灯(λ = 365 nm)照射下Fe(Ⅲ)在水溶液中同时光催化氧化磷酸三(2-氯乙基)酯(TCEP)和还原Cr(Ⅵ)的性能,考察Fe(Ⅲ)、Cr(Ⅵ)和TCEP初始浓度的影响,探讨UV/Fe(Ⅲ)体系中Fe(Ⅲ)/Fe(Ⅱ)氧化还原循环再生性,并验证UV/Fe(Ⅲ)对其他OPEs降解的适用性。结果表明:在UV/Fe(Ⅲ)体系中,光催化降解TCEP和还原Cr(Ⅵ)同时发生。Fe(Ⅲ)初始浓度的增加有利于Cr(Ⅵ)的光催化還原和TCEP的氧化降解。Cr(Ⅵ)的还原随着TCEP初始浓度的增加而增加,但不同Cr(Ⅵ)浓度对TCEP的降解效率影响并不明显。在UV/Fe(Ⅲ)体系中,5次循环实验都能实现TCEP的完全降解和Cr(Ⅵ)的还原。此外,该体系对其他OPEs与Cr(Ⅵ)的复合污染也有类似的光催化效果。Fe(Ⅲ)作为均相光催化剂可以处理含OPEs和Cr(Ⅵ)的复合污染。

关键词:三价铁;紫外光;复合污染;有机磷酸酯;六价铬

中图分类号:X53 文献标志码:A 文章编号:2096-6717(2021)06-0172-08

Abstract: Organophosphorus phosphate(OPEs)and hexavalent chromium (Cr(Ⅵ)) are common combined pollutants in electronic waste dismantling area.Simultaneous photooxidation of tris (2-chloroethyl) phosphate (TCEP) and photoreduction of Cr(Ⅵ) by ferric iron (Fe(Ⅲ)) in aqueous solution were studied under 300 W mercury lamp (λ=365 nm). The effects of the initial concentrations of Fe(Ⅲ), Cr(Ⅵ), and TCEP were investigated.The regeneration of Fe(Ⅲ)/Fe(Ⅱ) redox cycle in UV/Fe (Ⅲ) was studied. The applicability of UV/Fe(Ⅲ) to degradation of other OPEs was proved. The results showed that photocatalytic degradation of TCEP and reduction of Cr(Ⅵ) occurred simultaneously in UV/ Fe(Ⅲ) system. The increased Fe(Ⅲ) initial concentration was beneficial to the photocatalytic reduction of Cr(Ⅵ) and the oxidation of TCEP.The reduction of Cr(Ⅵ) increased with the increasing TCEP initial concentration.However, the Cr(Ⅵ) concentrations had no significant effect on TCEP degradation.In UV/ Fe(Ⅲ) system, TCEP can be degraded completely and Cr(Ⅵ) can be reduced in five cycles. Similar photocatalysis effects were observed for other OPEs. As a homogeneous photocatalytic method, UV/Fe(Ⅲ) can solve the combined pollution containing OPEs and Cr(Ⅵ) at the same time.

Keywords: ferric iron; ultraviolet light; combined pollution;organophosphorus phosphate;hexavalent chromium

近几十年来,重金属和有机化合物的复合污染因对环境和人类健康的危害而受到广泛关注[1-2]。有机磷酸酯(Organophosphate Esters,OPEs)作为溴代阻燃剂的替代品被广泛地应用于家具、建材以及电子设备原件的生产中。在生产、使用及处理过程中,OPEs通常会因为缺乏管理、处理不当等原因释放到环境中[3-4]。研究表明,电子垃圾拆解场地中OPEs污染水平要比其他地区高得多[5-6]。同时,铬作为一种重要的工业金属也在电子垃圾拆解场地中被广泛检出[7-9]。研究表明,这两种污染物均具有“致癌、致畸、环境持久”等特性[10-12],并且很容易通过迁移和转化进入到附近的土壤和地表水中,进而给周边居民健康带来风险[11, 13]。……

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