热带雨林环境中霉菌对PCB-Cu腐蚀行为的影响

目的 研究PCB-Cu在热带雨林环境下的霉菌腐蚀行为。方法 利用平板培养法筛选出PCB表面出现频率较高的两株真菌Fusarium solani和Daldinia eschscholtzii。利用干重法研究Cu2+对其生理活性的影响，利用扫描电子显电镜观测PCB-Cu表面的生物成膜情况，并利用动电位极化曲线研究其腐蚀电化学行为。 结果 两株真菌在6天时，均能在PCB-Cu表面形成生物膜，且在菌丝密集处，出现腐蚀产物的堆积。同时，薄液膜内Cu2+浓度的升高能抑制菌体的繁殖。相比于无菌组，两株菌株均能够在前期抑制PCB-Cu自腐蚀电位Ecorr的升高，在后期抑制PCB-Cu自腐蚀电位Ecorr的降低。结论 霉菌孢子接种到PCB-Cu表面后，由于初期PCB-Cu表面薄液膜中的Cu2+含量较少，对菌体的抑制作用较低，因此菌体活性较好，其分泌物抑制了PCB-Cu表面氧化膜的生成，从而在初期促进了PCB-Cu的腐蚀。但随着腐蚀反应的进行，PCB-Cu表面薄液膜中Cu2+浓度逐渐升高，菌体的活性受到抑制，因此腐蚀性分泌物含量下降，而此时附着在PCB-Cu表面的生物膜对基体起到了保护作用，从而开始抑制腐蚀。

Effect of Mold on the Corrosion Behavior of PCB-Cu in Tropical Forest Environment

The work aims to study the corrosion behavior of mold on PCB-Cu in tropical forest environment. Two fungi strains with the most high occurrence frequency, Fusarium solani and Daldinia eschscholtzii were selected from surfaces of PCBs via PDA culture . The dry weight method was used to study the effect of Cu2+ on biological activity. The biofilms on surface of PCB-Cu were observed by SEM and the polarization curves were adopted to investigate the electrochemical corrosion behavior. After 6 days, both fungi strains could form biofilm on PCB-Cu surface and accumulate corrosive products at mycelium concentration. At the same time, the increase of Cu2+ concentration in thin liquid membrane could inhibit the growth of bacteria. Compared with aseptic group, both strains could inhibit the increase of PCB-Cu self-corrosive potential Ecorr in the early stage and the decrease of PCB-Cu self-corrosive potential Ecorr in the later stage. After inoculation of fungal spores on PCB-Cu surface, the activity of fungi is better because the content of Cu2+ in the thin liquid film on PCB-Cu surface is lower in the initial stage, and the secretion inhibits the formation of oxide film on PCB-Cu surface, thus promoting the corrosion of PCB-Cu in the initial stage. However, with the corrosion reaction proceeding, the concentration of Cu2+ in the thin liquid film on PCB-Cu surface gradually increases, and the viability of fungi is inhibited, so the content of corrosive secretion decreases. At this time, the biofilm adhering to PCB-Cu surface protects the matrix and begins to inhibit corrosion.