Removal of halogenated by-products precursors in photocatalysis process enhanced with membrane filtration

In the article, the results of the research on removal of halogenated by-products precursors in a photocatalysis (PC) process enhanced with membrane filtration have been presented. In the research, the following by-products were analyzed as follows: trihalomethanes (trichloromethane, bromodichloromethane, dibromochloromethane, tribromomethane), haloacetic acids (monochloroacetic acid, monobromoacetic acid, dichloroacetic acid, bromochloroacetic acid, dibromoacetic acid, trichloroacetic acid), haloacetonitriles (bromochloroacetonitrile, dibromoacetonitrile, dichloroacetonitrile, trichloroacetonitrile), haloketones (1,1-dichloro-2-propanone, 1,1,1-trichloro-2-propanone), chloropicrin, and chloral hydrate. The analyses were conducted on the model solutions of humic and fulvic acids and also on the samples of surface water taken from the Goczalkowice Reservoir. These water samples were treated in a sequence of PC and membrane filtration. The PC process was conducted using TiO₂ and low-pressure monochromatic UV lamps. The samples of untreated water and the one obtained as a result of those processes were chlorinated with sodium hypochlorite in a dose which resulted in 3-5 mg/L of free chlorine after 24 h. After that time, the formed chlorination by-products were analyzed with gas chromatography, and the formation potential was calculated for each considered group of halogenated organic compounds.