O3/H2O2氧化降解环嗪酮研究

Ozonation of hexazinone in O_3/H_2O system

利用环嗪酮的拟一级氧化速率常数考察O3/H2O2体系对环嗪酮的去除效果,探讨了最佳反应条件及反应过程中过氧化氢的消耗情况,并利用IC、HPLC/MS和GC/MS等技术分析了氧化产物,对其降解途径进行了初步研究.结果表明:环嗪酮初始浓度为3mg·L-1、温度25℃、O3投量13mg·L-1、H2O2/O3物质的量比0.5、pH为8～9时,环嗪酮降解速率常数达0.075min-1;自来水中的无机离子和微量有机物对环嗪酮的氧化有一定的促进作用,反应过程中H2O2的消耗和环嗪酮的降解规律一致,HCO3-对环嗪酮的去除有明显的抑制作用,说明对环嗪酮的降解主要是羟基自由基的贡献;色谱质谱分析表明,环嗪酮的氧化经历脱甲基过程,生成的NO3-与去除的环嗪酮的物质的量比表明三嗪环已被打开,最终被矿化为NO3-、H2O和CO2等无机产物.

A process of hcxazinone oxidation using advanced method of O3/H2O2 was studied. Variation of pseudo - first - order reaction rate constant was investigated. The optimal reaction condition and consumption of hydrogen peroxide was determined. The reaction path in the degradation of hexazinone was discovered based on the products monitoring results by IC, HPLC/MS and GC/MS. The maximum of pseudo-first-order reaction rate constant was 0. 075 min- 1 at the condition of initial hexazinone concentration of 3 mg L- 1, temperature of 25℃ ozone dosage of 13 mg· L- 1, H2 O2/O3 ratio of 0. 5 and pH of 8 -9. The inorganic ions and trace organics matters contained in tap water accelerated the hexazinone oxidation. The consumption of H2O2 was proportional to the quantity of removed hexazinone, which was mainly due to hydroxyl free radical formation. Therefore, HCO3- obviously inhibited the degradation of hexazinone. The de-methyl-hexazinone was detected during the oxidation process. The triazine ring was broken and end products of NO3- , H2O and CO2 were achieved in the process of hexazinone degradation by O3/H2O2.