光助-电解锰渣/H_(2)O_(2)非均相体系氧化降解双酚S

Degradation of bisphenol S by photo-assisted electrolysis manganese slag/H_(2)O_(2) heterogeneous system

以电解锰渣作为光催化剂构建非均相类光Fenton体系,采用双酚S为模型化合物,研究了该反应体系中双酚S氧化降解的降解机制及影响因素,并建立了·OH的生成速率模型以及溶解性有机质(DOM)影响的预测模型.结果表明,电解锰渣中具有催化效果的铁和锰的质量含量分别为1.49%和2.28%;相比UV、UV/电解锰渣、UV/H_(2)O_(2)和电解锰渣/H_(2)O_(2)体系,电解锰渣/UV/H_(2)O_(2)光Fenton体系对双酚S具有更好的氧化降解效果,双酚S的降解效果与电解锰渣投加量、H_(2)O_(2)浓度呈正相关,与pH值、双酚S初始浓度呈负相关;溶液中析出的Fe和Mn的浓度与pH值呈负相关,且电解锰渣/UV/H_(2)O_(2)氧化体系反应浸出的共存活性金属组分不利于双酚S降解;电子自旋共振和自由基淬灭实验发现电解锰渣/UV/H_(2)O_(2)体系中氧化降解双酚的主要活性物种是·OH.采用异丙醇构建了该体系中·OH的生成速率模型,计算可得·OH的生成速率R_(·OH)^(f)在3.22×10^(-9)~1.1×10^(-8)mol/(L·s)之间,与硝基苯拟合计算出的R_(·OH)^(f)(6.5×10^(-9)mol/(L·s))一致.双酚S降解效率随着DOM浓度的增加而降低.基于自由基稳态动力学理论建立了DOM存在下电解锰渣/UV/H_(2)O_(2)体系中双酚S降解的动力学预测模型,发现模型的预测值与实验值较好符合,说明DOM主要通过淬灭体系中的·OH影响双酚S的降解.

Electrolytic manganese slag was used as photocatalyst to construct heterogeneous photo-Fenton reaction system.Bisphenol S was used as a model compound to study the degradation mechanism and influencing factors for bisphenol S in the reaction system.The formation rate model of·OH were constructed in the photo-Fenton reaction system.Based on·OH formation rate model,the prediction model of bisphenol S considering the effect of dissolved organic matter(DOM)were established.The results showed that the mass contents of Fe and Mn in electrolytic manganese with catalytic activity were 1.49%and 2.28%respectively.Compared with other degradation system(i.e.,UV,UV/electrolytic manganese slag,UV/H_(2)O_(2) and electrolytic manganese slag/H_(2)O_(2) system),the electrolytic manganese slag/UV/H_(2)O_(2) photo-Fenton system exhibited excellent oxidation degradation efficiency for bisphenol S,and the degradation efficiency of bisphenol S was positively correlated with the dosage of electrolytic manganese slag and H_(2)O_(2) concentration,but negatively correlated with pH and initial concentrations of bisphenol S.The concentrations of Fe and Mn in the solution was negatively correlated with the pH value,and the coexisting active metal components in the reaction leaching from electrolytic manganese slag were not conducive to the degradation of bisphenol S.Electron spin resonance and radical quenching experiments showed that the main active species for bisphenol S degradation in electrolytic manganese slag/UV/H_(2)O_(2) system was·OH.The formation rate model of·OH in this system was constructed by using isopropanol,and the formation rate of·OH was estimated to be 3.22×10^(-9)~1.1×10^(-8)mol/(L·s),which was consistent with R_(·OH)^(f)(6.5×10^(-9)mol/(L·s))calculated by nitrobenzene fitting.The degradation efficiency of bisphenol S decreased with the increase of DOM concentrations.Based on the theory of free radical steady-state kinetics,a kinetic prediction model of bisphenol S degradation in electrolytic manganese slag/UV/H_(2)O_(2) system in the presence of DOM was established.It was found that the predicted values from the model was in line with the experimental data,indicating that DOM mainly affected the degradation of bisphenol S through quenching·OH in the system.