Corrosion of Q235 steel affected by Pseudodesulfovibrio cashew differed with electron acceptors

电子受体对Pseudodesulfovibrio cashew作用下Q235钢腐蚀的影响

Sulfate and nitrate reducing bacteria are important culprits for microbiologically influenced corrosion(MIC)using sulfate and nitrate as electron acceptors,respectively.Sulfate and nitrate hold different standard electrode potentials,which may lead to differences in corrosion,but their effects on corrosion by the same bacteria have not been reported.The corrosion of Q235 steel affected by Pseudodesulfovibrio cashew(P.cashew)in the sulfate and nitrate media under carbon starvation was studied.It was found that sulfate and nitrate did not lead to differences in corrosion under abiotic conditions.However,P.cashew promoted corrosion in both cases,and the consumption of H_(2)was the main mechanism for MIC.In addition,corrosion was more severe in the sulfate media.The higher corrosivity of P.cashew with sulfate as the electron acceptor is closely related to the higher number of sessile cells in the biofilm,higher bacterial motility,more hydrogen production pathways,and the increased gene expression of enzymes related to energy synthesis.

微生物腐蚀(MIC)是指微生物的自身生命活动及其代谢产物直接或间接地加速金属材料腐蚀过程。硫酸盐还原菌和硝酸盐还原菌是导致MIC的重要腐蚀性微生物,其分别使用硫酸盐和硝酸盐作为电子受体。硫酸根和硝酸根不同的标准电极电位有可能导致腐蚀的差异,但它们对同一细菌腐蚀的影响尚未报道。为此,本文研究了在碳饥饿条件下,Pseudodesulfovibrio cashew(P.cashew)在硫酸盐和硝酸盐介质中对Q235钢腐蚀的影响。研究发现,在非生物条件下,硫酸盐和硝酸盐不会导致明显的腐蚀差异。然而,P.cashew在这两种介质中都促进了Q235钢的腐蚀,其中P.cashew对H_2的消耗是促进腐蚀的主要机制。此外,在硫酸盐介质中,P.cashew作用下Q235钢的腐蚀更为严重,这与生物膜中更多的固着细胞数量、更强的细菌运动性、更多的产氢途径以及与能量合成相关的酶的基因表达增加密切相关。