Platinum Electrode Response in Anaerobic Sludge

Abstract

Response time and stability of platinum electrodes in anaerobic environments are critical factors for determining the appropriate electrode potential in most experimental studies. In this research, several pretreatment techniques, including chemical and polarization (anodic and cathodic) methods, were investigated to find ones that reduced response time and enhanced electrode stability. Results indicated that chemical pretreatment of a dry platinum electrode with air, sludge, stannous chloride, and thioacetamide/hydrogen sulfide (H2S) and chemical pretreatment of a wet electrode by thioacetamide/H2S produced the most rapid stable response when the electrode was placed in an anaerobic sludge. Chemical pretreatment with 6 M nitric acid, water, hydrogen gas, and sludge was not effective. Pretreatment by cathodic polarization (H2 cathode in 0.05 M hydrochloric acid electrolyte) showed the best response (rapid and stable) with 94 to 97% of the 24‐hour reading in 20 minutes. These results are consistent with current understanding of the microbial processes and suggest that a rapid and stable response requires a coating of molecular hydrogen on the electrode surface.