UV强化草酸络合Fe^(2+)活化过硫酸盐氧化苯胺研究

Enhanced degradation of aniline by PS oxidation in the presence of UV and ferrous oxalate

采用UV强化草酸络合Fe2+活化过硫酸钠(PS)氧化降解苯胺,研究了UV光照促进苯胺降解的作用机制,考察了pH、草酸浓度和UV光照强度对PS活化及苯胺降解的影响.结果表明,引入UV光照后,草酸络合Fe2+活化PS体系中的PS活化率和苯胺降解率分别提高了68%和41%.在该过程中,UV可通过光解或光电离水分子产生·OH、促进发生光化学Fenton反应、直接活化PS等作用机制降解苯胺,但通过光化学反应促进Fe2+循环转化是提高PS持续活化效果和苯胺去除的首要作用机制;中碱性及强酸性环境因不利于Fe(C2O4)3-3形成,会对PS活化过程产生抑制,但当初始pH为7和9时,由于PS活化分解促进反应体系pH下降,PS活化及苯胺降解均取得较好效果;草酸浓度的增加有利于PS活化,但当草酸浓度高于2.5 mmol·L^(-1)时,会对SO·-4产生强烈竞争,导致苯胺降解率出现下降;增加UV光照强度能显著促进PS活化和苯胺氧化去除,当UV光照强度达到117μW·cm-2时,反应150 min后,PS的分解率和苯胺的去除率均可达到100%.

Enhanced oxidative degradation of aniline by sodium persulfate（ PS） in the presence of ferrous oxalate and UV irradiation was studied. The mechanisms of aniline degradation induced by UV irradiation and the effects of pH,oxalic acid concentration,UV irradiation intensity on PS activation and aniline degradation were investigated. The obtained results indicated that the efficiency of PS activation and aniline degradation increased by 68% and41%,respectively,when UV irradiation was introduced. The enhancement of aniline degradation in the presence of UV irradiation was probably attributed to a variety of mechanisms,such as photochemical homolysis or ionization of H2 O into ·OH,photo-induced Fenton reaction and direct activation of PS,but the transformation of Fe3＋to Fe2＋which accelerated the PS activation was the dominant mechanism. In addition,it was found that the neutral,alkaline and extremely acidic conditions retarded the formation of Fe（ C2 O4）3-3,which might result in the low efficiency of PS activation. However,the efficiency of PS activation and aniline degradation at initial pH of 7 and 9 were considerable due to the pH decrease during the reaction. The increase of oxalic acid concentration promoted the PS activation,but when the concentration was higher than 2.5 mmol·L^（-1）,the strong competition of sulfate radicals due to the excessive oxalic acid reduced the aniline degradation efficiency. The efficiency of PS activation and aniline removal was improved significantly with theincrease of UV irradiation intensity,and both of them achieved almost 100% in 150 min when the UV irradiation intensity was 117 μW·cm-2.