再生水环境中杀菌剂对SS316L表面生物膜活性与电化学行为影响

Effects of fungicides on the biofilm activity and electrochemical behaviors of stainless steel SS316L in the reclaimed water

本文应用生物化学和电化学分析方法研究了发电厂循环水系统常用杀菌剂NaClO和十二烷基二甲基苄基氯化铵(1227)对硫酸盐还原菌(SRB)脱氢酶活性,胞外聚合物(EPS)以及对不锈钢SS316L表面生物膜电化学行为的影响.结果表明,2种杀菌剂均有效地降低了细菌脱氢酶活性和细菌代谢产物EPS中多糖和蛋白质的含量.其中NaClO和1227对多糖削减水平相当,平均降幅均为72 mass%;NaClO对蛋白质削减效果较为明显,平均降幅为60 mass%,而1227对蛋白质的平均降幅为48 mass%.添加2种杀菌剂后,SS316电极表面溶解电流随时间缓慢下降,表明这两种杀菌剂在一定程度上能够减缓SRB生物膜对SS316L表面的电化学腐蚀.1227能够维持SS316电极表面较为稳定的溶解电流和钝化区间.

In this paper,the effects of fungicides（NaClO and 1227） on the dehydrogenase activity of sulfate-reducing bacteria and their extracellular polymeric substances（EPS）, as well as electrochemical behaviors of biofilms on the stainless steel SS316 L in power plant reclaimed water were investigated using biochemical and electrochemical analysis.The results show that these two fungicides effectively reduced the contents of polysaccharides and proteins in the extracellular polymeric substances.NaClO and 1227 had a similar effect on reducing polysaccharides with an average decline of 72 mass%.NaClO had a more significant effect on reducing proteins than 1227 with an average decline of 60 mass% vs 48 mass%.The results from the potentiodynamic curve analysis for the SS316 L electrodes show that the passive current density diminished with time,indicating that these two fungicides had inhibition effect on biofilm corrosion of SS316 L.Adding 1227 can maintain the steady-state passive current density and broad passive range.