阳离子淀粉与硫化镉复合膜对染料的选择性光降解  

Selective photocatalysis degradation of dyes using CdS composited with a cationic starch film

作　　者：薛宇翔 李娜[1] 高博强 杨琥[1] Yuxiang Xue;Na Li;Boqiang Gao;Hu Yang(State Key Laboratory of Pollution Control and Resource Reuse,School of the Environment,Nanjing University,Nanjing 210023,China)

机构地区：[1]南京大学环境学院,污染控制与资源化研究国家重点实验室,南京210023

出　　处：《中国科学：化学》2020年第6期707-719,共13页SCIENTIA SINICA Chimica

基　　金：国家自然科学基金(编号:51778279,51978325)资助项目。

摘　　要：对复杂污染物进行有效分离,实现资源化再利用具有重要的现实意义.光催化具有氧化性强的特点,但降解不具有选择性,很难实现资源化.本文针对混合染料废水,选用对不同染料具有不同吸附能力的阳离子改性淀粉(St-CTA)作为光催化剂CdS的载体,采用原位生成法制成复合膜(CdS/St-CTA),详细考察了CdS/St-CTA在茜素绿(AG25)、甲基橙(MO)和罗丹明B(RhB)单组分与二元染料组分溶液中的吸附降解行为.CdS/St-CTA在AG25/RhB和MO/RhB混合溶液中分别对AG25和MO具有良好的选择性降解作用,而对Rh B没有去除效果.这是由于St-CTA载体对不同染料具有不同的吸附性能所造成的.CdS/St-CTA的选择降解性能不受Cl^-、SO4^2-和CO3^2-等共存阴离子及pH的影响.此外,使用后的CdS/St-CTA不需要脱附或其他再生处理,便可应用于下一次降解处理,循环5次后仍能保持原有的降解效率,证明CdS/St-CTA具有稳定的回收再利用性能.本文提出的载体负载光催化剂"选择吸附富集-选择光降解"这一策略,具有良好的普适性,对处理不同污染物均具有一定的参考价值.Resource utilization through effective separation of complex wastes is of great realistic significance in water and wastewater treatment.Photocatalytic degradation is a powerful water treatment technology with strong oxidation,but has no selectivity in degradation of various coexisting contaminants.In this work,a cationic starch(St-CTA)with selective adsorption performance was used as a catalyst carrier,and a complex film composed of St-CTA and a popular catalyst,CdS,(CdS/St-CTA)was designed and fabricated using in situ formation method.This starch-based complex film was used to remove various organic dyes(alizarin green(AG25),methyl orange(MO),and rhodamine B(RhB))from their single and binary dye solutions.CdS/St-CTA exhibited evident selective photocatalysis degradation of AG25 and MO in AG25/RhB and MO/RhB binary systems,respectively,and had nearly no effect on RhB.It was because that the cationic groups on RhB hindered its adsorption on St-CTA carrier.Differently,St-CTA can effectively adsorb anionic AG25 and MO due to electrostatic attractions,causing the following selective photodegradation.The selective degradation of CdS/St-CTA to AG25 and MO rather than RhB was unchanged under different pHs and aforementioned coexisted anions.Furthermore,this complex film did not require regeneration and could be reused directly without removal capacity loss after five recycles.Therefore,a new and simple strategy of"selective adsorption enrichment and then selective photocatalysis degradation"with general applicability was provided to realize the effective separation and recovery of target contaminants in water by photocatalytic degradation technology.

关 键 词：改性淀粉/CdS复合膜 混合染料 选择性吸附 选择性光催化降解 选择性光催化降解机制 

分 类 号：O643.36[理学—物理化学] O644.1[理学—化学] X703[环境科学与工程—环境工程]