A preliminary investigation on the photocatalytic degradation of a model humic acid

The research reported addresses the destructive removal of humic acid in aqueous medium by a photocatalytic oxidation process. Bench scale experiments were carried out using titanium dioxide as the photocatalyst and Black Light Fluorescent Lamp as the irradiation source. Following 1 h irradiation 40 % TOC and 75% Color₄₀₀ removals were attained for 50 mg/L humic acid solution in the presence of 1.0 mg/mL TiO2. The optimum TiO₂ loading was found to be 1.0 mg/mL. Acidic medium accelerated the photocatalytic degradation rate whereas a retardation factor of 0.4 was recorded in alkaline medium. The evaluation of the THMFPs of the photocatalytically treated humic acid solutions revealed that the destructive removal of humic acid was effective enough to keep the THM levels below the maximum contaminant level of 0.10 mg/L (USEPA).