The photocatalytic activity of bismuth oxychloride (BiOCl) toward sulfamethoxazole (SMX) elimination was investigated. BiOCl was synthesized according to a simple method using thiourea. Its physicochemical characteristics were determined by nitrogen physisorption, X-Ray diffraction, diffuse reflectance spectroscopy, scanning electron microscopy and transmission electron microscopy. Simulated solar irradiation and 1 g/L BiOCl, could effectively remove 0.5 mg/L SMX in less than 90 min. An increase in SMX concentration from 0.25 mg/L to 4 mg/L decreased the observed kinetic constant. Concerning the pH effect, it was found that under alkaline conditions SMX removal was slightly hindered. The water matrix's influence on SMX removal was explored, carrying out experiments in real water matrices, (bottled water (BW) and secondary effluent (WW)). Interestingly SMX removal was not practically altered in WW secondary effluent, but it was slightly hindered in BW bottled water. Experiments, performed in synthetic matrices, revealed that the presence of bicarbonates and chlorides slightly slowed down degradation kinetics, while humic acid enhanced SMX removal at concentrations up to 10 mg/L. Finally, an enhancement on SMX degradation was observed in the presence of persulfate. Quenching experiments of potential reactive species revealed that SMX degradation takes place mainly through reaction with hydroxyl radicals and photogenerated electrons.
Keywords: Bismuth oxychloride; antibiotics; enhancement; real water matrix; solar photocatalysis.