Initial Adhesion of Sulfate Reducing Bacteria on Materials with Different Surface Charge

Abstract

Sulphate-reducing Bacteria(SRB) is the most popular corrosive microorganisms in marine environment and their initial adhesion on materials is an important stage of microbiological induced corrosion(MIC). Three kinds of thiol molecules, 6-Amino-1-hexanethiol, 6-Mercapto-1-hexanol and 6-Mercaptohexanoic acid, were applied onto the Au surface, forming three kinds of selfassembled monolayer films(SAMs), which were positively charged, electrically neutral and negatively charged at p H 7.4 respectively. Then the influence of surface charge of SAMs on SRB adhesion was investigated by measurement with electrochemical impedance spectroscopy(EIS) and observation with scanning electron microscopy(SEM). On the positively charged surface the initial adhesion of SRB was promoted, while on the negatively charged surface the process was inhibited and the reversible adhesion time was prolonged. Moreover, the change rate of charge-transfer resistance(△Rct%) may be adopted as an index of the tendency of SRB adhesion to a certain extent.