抗坏血酸提高稀土复合材料催化降解染料性能研究

Studyon ascorbic acid improving thecatalyticdegradation of dyeby rare earth composites

本文以β-环糊精(CD)为载体,通过负载Fe_(3)O_(4)和稀土铈(Ce),制备了稀土复合材料Ce-Fe-CD,形成了可有效降解有机物的非均相芬顿反应Ce-Fe-CD/H_(2)O_(2)体系。为提高催化降解效果,本文用两种方式引入还原剂抗坏血酸(AA):①在非均相芬顿反应过程中直接投加AA,形成AA/Ce-Fe-CD/H_(2)O_(2)体系;②利用AA活化稀土复合材料,获得AA-Ce-Fe-CD复合材料,形成AA-Ce-Fe-CD/H_(2)O_(2)体系。实验结果表明,AA-Ce-Fe-CD/H_(2)O_(2)和AA/Ce-Fe-CD/H_(2)O_(2)对染料的降解率分别为86.9%和83.0%,比未使用AA时分别提高了34.4%和30.5%,且AA-Ce-Fe-CD/H_(2)O_(2)体系有更高的H_(2)O_(2)的利用率,可有效减少H_(2)O_(2)的使用量。电子自旋共振波谱分析表明·OH为两种体系中起主要作用的活性自由基。AA对于金属离子的还原作用和螯合作用是提高稀土复合材料催化效率的主要原因。

In this paper,β-cyclodextrin(CD)was used as a carrier,Fe_(3)O_(4) and rare earth cerium(Ce)were loaded on CD to prepare the rare earth composites(Ce-Fe-CD).AheterogeneousFentonreaction,Ce-Fe-CD/H_(2)O_(2) system which could effectively degrade organics was formed.In order to improve the catalyticdegradation effect,the reducing agent ascorbic acid(AA)was introduced in two ways:(1)the AA/Ce-Fe-CD/H_(2)O_(2) system was constructed by directly adding AA in the heterogeneousFenton reaction process;(2)the AA-Ce-Fe-CD compositeswere obtained by AA activation,and the AA-Ce-Fe-CD/H_(2)O_(2) system was formed.Experimental results showed thatthe degradation rate of dyes in AA-Ce-Fe-CD/H_(2)O_(2) and AA/Ce-Fe-CD/H_(2)O_(2) system was 86.9%and 83.0%,and was increased by 34.4%and 30.5%compared with that Ce-Fe-CD/H_(2)O_(2) system,respectively.Furthermore,there were the higher utilization rate of H_(2)O_(2)in the AA-Ce-Fe-CD/H_(2)O_(2) system,which could effectively reduce the usage of H_(2)O_(2).Electron spin resonance spectroscopy analysis showed·OH was the main active species produced in both systems.The reduction and chelation of AA to themetal ions were the main reasons for improving the catalytic efficiency of rare earth composites.