活化过硫酸盐氧化地下水中苯酚的动力学研究

以柠檬酸(CA)络合亚铁离子CA-Fe(II)为活化剂,活化过硫酸盐(S2O82-,PS)产生强氧化剂硫酸根自由基(SO4·-),进而催化氧化苯酚.从CA/Fe(II)物质的量比、Fe(II)浓度、过硫酸盐(PS)投加量和苯酚初始浓度4个因素来考察络合亚铁离子活化过硫酸盐氧化去除苯酚的动力学.结果表明,随着PS投加量的增加,苯酚的去除率随之提高;但随着苯酚初始浓度的增加,去除率逐渐降低;CA/Fe(II)物质的量比为1/5时,能够保持水溶液中足量的亚铁离子,有利于苯酚的氧化去除;当PS/CA/Fe(II)/苯酚物质的量比为100/10/50/1时,苯酚的去除率最高,反应15min后去除率达到98%,此时,苯酚的氧化反应速率k也达到最高值0.430min-1.活化过硫酸盐氧化去除苯酚的过程基本符合准一级动力学,在CA/Fe(II)/苯酚物质的量比为10/50/1条件下,苯酚氧化反应速率与过硫酸盐投加量呈线性正相关(R2=0.953).

Kinetics study of activated persulfate oxidation of phenol in ground water

The phenol oxidation by sulfate free radical (SO4·-) formed in the activation of persulfate by citric acid chelated ferrous ion (CA-Fe(II)) was investigated in this study. The influence of different factors, such as CA/Fe(II) molar ratio, Fe(II) concentration, initial S2O82- molar amount and phenol concentration on the kinetics of phenol oxidation by chelated Fe(II) activated persulfate was described in detail. Results indicated that the removal efficiency of phenol was significantly increased with increasing persulfate dosage, but decreased with increasing initial phenol concentration. A CA/Fe (II) molar ratio of 1/5contributed to phenol removal on maintaining sufficient quantities of available Fe (II) in solution. The highest phenol removal (98%) can be obtained within a 15min with the PS/CA/Fe (II)/phenol molar ratio of 100/10/50/1 and the highest oxidation rate (0.430min-1) was gained. The phenol oxidation by chelated ferrous ion activated persulfate followed the pseudo-first-order kinetics reaction. With the CA/Fe(II)/phenol molar ratio of 10/50/1, the phenol oxidation rate constant exhibited a linear trend as a function of initial persulfate concentration, R2 = 0.953.