生物滴滤净化气态苯乙烯的微电解强化实验研究

实验采用微电解-生物滴滤联合装置净化气态苯乙烯,苯乙烯进气浓度控制在320~548 mg·m~(-3)之间,停留时间(RT)为108 s,电流为50m A,喷淋液pH为6.0~6.5.结果发现,稳定后苯乙烯去除率能维持在95%以上.微电解产生的活性物质能促进微生物的生长,并可通过协同作用改善系统的运行性能.稳定运行阶段,实验中外加电流从50 m A上升到150 m A时,苯乙烯的去除效率增加,且明显高于无电流作用时的去除效率.喷淋液pH对苯乙烯去除率的影响较大且复杂,有外加电流时的实验最佳pH比无电流时更偏酸性.当系统有适量的H+存在下,有利于生物膜中的还原反应,但pH值过小会影响微生物正常的新陈代谢,因此,喷淋液的pH值存在一最佳值.系统关停10 d后重启,气态苯乙烯的去除效果在第4 d就能恢复.根据扫描电镜结果,挂膜后填料表面的微生物种类和形态比较丰富,主要与微生物降解的初始目标物有关.

Experimental study on microelectrolysis intensification for degradation of the gaseous styrene in a biotrickling filter

Purification of styrene by microelectrolysis and biological filtration was studied in this paper. The results indicated that the styrene inlet concentration was controlled between 320~548 mg·m^-3,and the removal efficiency could remain above 95% after stably running,when residence time (RT),current,and pH of spray liquid were controlled at 108 s,50 mA and 6.0~6.5,respectively. The active substance produced by microelectrolysis promoted the growth of microorganism,and the operating performance of the system was improved through a coupling effect. In the stable operation stage,the styrene removal efficiency gradually increased when the external current increased from 50 mA to 150 mA,and it was significantly higher than that of no current effect. The impact of pH of circulating liquid on styrene removal efficiency was large and complex. The optimal pH with the external current was more acidic than without current. Addition of appropriate amount of H⁺ in the system was beneficial to the reduction reaction in the biological membrane,but if the pH value is too small it affected the normal metabolism of microorganisms,so there was an optimum pH value of the spray liquid. The removal effect can be restored at the fourth day,after closing system for ten days and restart. According to the results of scanning electron microscopy,the species and morphology of the microorganism on the surface of packing were very rich,which was mainly related to the initial target of microbial degradation.