Study of corrosion behavior of copper in 3.5 wt.% NaCl solution containing extracellular polymeric substances of an aerotolerant sulphate-reducing bacteria

Extracellular polymeric substances (EPS) of an aerotolerant sulphate-reducing bacteria were extracted, and they contained mainly polysaccharides and proteins. Effects of EPS on corrosion behavior of copper were investigated through electrochemical methods and surface analysis techniques in 3.5 wt.% NaCl solution under aerobic condition. Results indicated that after a short-period immersion, EPS inhibit copper corrosion, and their inhibition effect decreases with increasing EPS concentration. For long-term immersion, copper corrosion is promoted due to the destruction of the protective Cu2O film by EPS.