自掺杂型BiOBr光催化剂-过硫酸盐协同体系可见光降解腐殖酸的研究

Synergistic System of Self-doping BiOBr Photocatalyst with Persulfate and Their Visible Photocatalytic Degradation of Humic Acid

通过建立一种不同价态Bi自掺杂型BiOBr可见光催化剂及过硫酸盐体系,对腐殖酸的去除进行了系统地研究。结果表明自掺杂BiOBr-过硫酸盐(PS)体系能有效去除腐殖酸,且1 h内去除率可达75%以上,远高于BiOBr、自掺杂BiOBr本身或PS单独存在时的效果。该不同价态Bi自掺杂型BiOBr催化剂由于其较窄的禁带宽度和较高的光生电子-空穴对的分离效率为可见光催化提供了有利的条件。而通过自由基捕获实验确定了主要活性物种从染料降解过程中的空穴(h+)和超氧自由基(·O2-)转变为了硫酸根自由基(·SO4-)和羟基自由基(·OH),因而达到了产生更强的活性自由基进而促进难降解有机污染物处理的目的。

A system of Bi self-doping BiOBr with different valence states and persulfate was established to study about the degradation of humic acid.The results showed that the self-doping BiOBr-persulfate system could effectively remove humic acid,and the removal rate was up to 75%within 1h,which was much better than BiOBr,persulfate or self-doping BiOBr,respectively.The Bi self-doping BiOBr with different valence states provides favorable conditions for visible photocatalysis due to its narrow bandgap and high separation efficiency of photogenerated electron-hole pairs.Whereas the main active species were determined through the trapping experiments.The main active species were changed from holes(h+)and super-oxide radical(·O2-)in the photocatalysis process of dyes to sulfate radical(·SO4-)and hydroxyl radical(·OH)in the degrada-tion of humic acid,which achieved the purpose of generating radicals with stronger oxidizability to promote the degradation of recalcitrant organic pollutants.