无机阴离子对CuO-H_2O_2氧化苯酚废水的影响

Influences of Inorganic Anions on Oxidation of Phenol by CuO-H_2O_2

以苯酚为模型底物,研究了中性低温常压条件下无机阴离子对CuO-H2O2氧化苯酚废水的影响及机制.结果表明,CuO-H2O2能高效彻底氧化苯酚,10min氧化率达94.7%,氧化遵循羟基自由基机制.无机阴离子对氧化效果有不同影响,浓度越高影响越显著.HCO3-加速H2O2的无效分解,当浓度从0增加到20mmol·L-1时,H2O2分解速率常数由0.3738min-1提高到0.5347min-1,TOC去除速率常数由0.267min-1下降到0.0194min-1.HPO24-通过抑制H2O2分解实现对苯酚的氧化抑制,H2O2分解速率常数及TOC去除速率常数分别由0.3738min-1、0.267min-1降低到0.0338min-1、0.0338min-1.Cl-能够促进H2O2有效分解,对苯酚氧化有利,H2O2分解速率常数及TOC去除速率常数分别由0.3738min-1、0.267min-1提高到0.6040min-1、0.3879min-1.NO3-、SO42-对H2O2的分解及苯酚的氧化影响不大.

Phenol was selected as a model pollution substrate. The influences and mechanism of inorganic anions on its oxidation were investigated in neutral solution at low temperature and atmospheric pressure. Results showed that phenol could be removed efficiently by CuO and H2O2 with 94.7 % removal rate in 10min, which followed hydroxyl radical oxidation mechanism. Inorganic anions influenced the oxidation with different mechanisms. Higher concentration would lead to more significant influences. HCO3^- accelerated the inefficient decomposing of H2O2 . The decomposing rate constants increased from 0. 373 8 min^- 1 at concentration of 0 mmol· L^- 1 to 0. 534 7 min^- 1 at concentration of 20 mmol· L^- 1. The TOC removal rate constants decreased from 0.267 min^-1 to 0.019 4 min^-1 correspondingly. HPO4^2- retarded the H2O2 decomposing and inhibited the phenol oxidation. The decomposing rate constants of H2O2 and the removal rate constants of TOC decreased from 0.373 8 min^-1 , 0.267 min^-1 to 0.033 8 min^-1 , 0.033 8 min^-1 respectively. Cl^- was good at H202 decomposing and phenol removal with simultaneously increasing the H2O2 decomposing rate constants and the TOC removal rate constants from 0. 373 8 min^-1 , 0. 267 min^-1 to 0. 604 0 min^- 1, 0. 387 9 min^- 1 respectively. NO3^- and SO4^2- had few influences on H2O2 decomposing and phenol removal.