Evaluation of the solar photocatalytic degradation of organochlorine compound trichloroethanoic acid using titanium dioxide and zinc oxide in the Caribbean region

Abstract

Advanced oxidation processes driven by solar energy can be an efficient method in removing organochlorine compounds from river water especially in tropical environments like the Caribbean region. The feasibility of solar photocatalytic degradation of an organochlorine compound, namely trichloroethanoic acid (TCA), which is commonly used in the Caribbean islands of Trinidad and Tobago, was separately assessed using titanium dioxide and zinc oxide as photocatalysts in suspended solution. Overall the prototype solar photoreactor operated and performed efficiently for the photodegradation of TCA. This study showed that a basic photocatalytic oxidation method for treating water using solar energy as the primary driver gives enhanced decomposition rates of the organochlorine compound when coupled to the additional application of the two separate semiconductor photocatalysts. The results further showed that for varying concentrations of TCA and photocatalysts alike, the organochlorine compound could be completely photocatalytically degraded using short exposure times under the applied influx of solar radiation. This means that this process could be optimised by judicious use of sensors so that dosage rates of the photocatalyst could be altered with variations in influent contamination levels, and the exposure time in the reactor could be altered according to daily variations in solar radiation intensity.