Oil Solubilization Using Surfactant for Biohydrogen Production

Abstract

Oily wastewater is a potential source for biohydrogen production due to its high organic content. Incorporation of surfactant could enhance the solubilization of oil in water, and thus increase its biodegradability. The first part of this work studied the influence of surfactant concentrations (0-240 CMC) and temperatures (28-70 °C) on oil solubilization in aqueous solution. Results from batch tests showed that the oil solubilization improved as the surfactant concentration increased up to 100 CMC. As high as 0.002 mg/L oil concentration could be solubilized at 1 CMC and 55 °C, which was 90 times higher than that obtained without surfactant application. Moreover, the time to reach oil-in-liquid equilibrium could be shortened by increasing the temperature. In the second part, the effect of surfactant addition on hydrogen production was investigated at pH 5.5 and 55 °C. In 148 h batch assays, the highest hydrogen production observed was 19.3 mL at 1 CMC while it was 8.7 mL at no surfactant. Further investigation at 1 CMC revealed that surfactant degradation to H2 was 2.36 mL, thus the effect of surfactant to enhance oil degradability was 0.24 L H2 per liter of aqueous solution under excess oil condition.