Production of electricity from ethanol and ammonium based wastewater via photo-electrochemical process

Abstract

A PEC cell is tested with two types of electrolyte (e.g., electrolyte pollutant and alcohols) under irradiation with a Xenon lamp through an IR cutoff filter (IRA-25S). The main objective of this study is to optimize the production of electricity from wastewater containing ethanol and ammonium using a photo-electrochemical (PEC) process. DOE statistical analysis was used to optimize the parameters that influenced the process, namely the active area of photoanode and the concentration of electrolyte. The significance level of the active area of a photo-anode was found to be within 0.5–1.0 cm2, the electrolyte concentrations were found to be 5–20% by volume and the types of electrolytes used included ammonia and an ethanol aqueous solution. For the optimization process, the response surface method (RSM) using central composite design (CCD) was applied to generate a map of the response. The results were statistically analyzed using an analysis of variance (ANOVA) to identify the factors that influence the production of the current density from a PEC cell. An electrolyte containing ethanol was found to produce higher currents than electrolyte containing ammonium. The optimum parameters that produced the maximum current density of 0.77 mA/cm2 were achieved using an ethanol electrolyte with an active area of 0.73 cm2 and a concentration of 20% by volume. Confirmation experiment showed that the current density is about 97% similar to the expected value that is 0.75 mA/cm2.