臭氧氧化法分解聚驱采油废水中水解聚丙烯酰胺的过程分析

Degradation Process of Hydrolyzed Polyacryamide in Polymer Flooding Produced Wastewater by Ozonation

对含水解聚丙烯酰胺(HPAM)的模拟废水分别采用单独臭氧氧化和电絮凝耦合臭氧氧化两种方法进行处理。考察处理方法对HPAM降解的影响,采用GC-MS和FTIR方法对HPAM降解物进行表征以分析HPAM降解的过程。实验结果表明,单独臭氧氧化处理模拟废水时,在臭氧用量4.2 mg/L、废水pH=10、反应120 min的条件下,COD和HPAM的去除率分别为37.1%和83.4%;电絮凝耦合臭氧氧化处理模拟废水时,经电絮凝30 min后,再臭氧氧化120 min,COD和HPAM的去除率分别为82.2%和94.4%。臭氧氧化降解HPAM的过程可推断为:HPAM分子经断链分解为低相对分子质量的聚合物,低相对分子质量的聚合物继续氧化生成丙烯酸和丙烯酰胺的中间体,中间体再进一步氧化为烷烃、醛酮类、酯类等物质,最终彻底矿化。

Single ozonation process and electrocoagulation coupled with ozonation were separately applied to the treatment of simulated polymer flooding produced wastewater containing hydrolyzed polyacryamide（HPAM）. The degradation of HPAM by the treatments was investigated and the degradation products were characterized by means of GC-MS and FTIR. The experimental results indicated that in the single ozonation, under the conditions of reaction time 120 min, wastewater pH 10 and ozone dosage 4.2 mg/L, the removal rates of COD and HPAM reached 37.1% and 83.4%, respectively, while in the electrocoagulation coupled with ozonation, under the conditions of electrocoagulation 30 min and then ozonation 120 min, the removal rates reached 82.2% and 94.4%, respectively. The degradation process of HPAM was inferred as follows： firstly, HPAM was broken chain and low relative molecular mass polymers formed, which were oxidized into acrylic acid and acrylamide; then, they were oxidized into alkanes, aldehydes, ketones, carboxylic acids and lipids sequentially; and finaUy, they were completely mineralized.