水滑石纳米晶负载铁磺基席夫碱光催化降解有毒有机污染物

Degradation of toxic organic pollutants by iron(Ⅲ)Schiff-base/LDH complex under visible irradiation

为了研究负载型金属有机配合物作为异相光催化剂对有毒有机污染物的催化降解性能,合成了双(5-磺基水杨醛)邻苯二胺席夫碱(SSPA)铁配合物(FeSSPA)和氯型水滑石(LDH-Cl)纳米晶载体,通过离子交换法将FeSSPA负载在LDH-Cl上,制备得到了水滑石负载磺基席夫碱铁复合物(FeSSPA-LDH)。紫外-可见漫反射光谱(UV-VisDRS)表明,该负载型复合物在可见光区有较好的响应。在可见光照射下(λ>420 nm),FeSSPA-LDH活化分子O_2降解有毒有机染料罗丹明B(RhB)及无色小分子2,4-二氯苯酚(2,4-DCP)的催化特性研究表明,其对有色染料和无色有机物均可有效降解。苯甲酸荧光光度法测定体系中产生的高活性氧化物种羟基自由基,表明反应机理主要涉及羟基自由基氧化机理。

Fe（ Ⅲ）-bis-Schiff-base-5-sulfonic-salicylidene-o-phenylenediamine（ FeSSPA）,an iron（ Ⅲ）Schiff base complex,was prepared via a chemical synthetic method. Layered double hydroxide（ LDH-Cl）,as a support,was prepared by a hydrothermal method. FeSSPA-LDH,a heterojunction photocatalyst,was then synthesized via an ion exchange technique by immobilizing FeSSPA on LDH-Cl. The catalyst was characterized by UVVis diffuse reflectance spectrum（ UV-VisDRS）,and X-ray diffraction analyses. The photocatalytic degradation of rhodamine B（ RhB） and 2,4-dichlorophenol（ 2,4-DCP） with visible-light irradiation under neutral conditions（ pH 6. 2） were used as probe reactions to evaluate the photocatalytic activity of Fe SSPA-LDH. Under the optimal conditions,RhB was completely decolorized in 10 h and 100% removal of 2,4-DCP was achieved in 15 h. Hydrogen peroxide（ H2O2） and hydrogen radicals（ ·OH） were detected during the RhB degradation process,and the experimental results indicated that the photocatalytic activity of FeSSPA-LDH was mainly attribute to ·OH.