Photo-oxidation kinetics of sugars having different molecular size and glycosidic linkages for their complete mineralization to subunits by bare/Ag–TiO 2 under UV irradiation (original) (raw)

Food industries discharge a large quantity of waste water effluent containing a variety of water-soluble carbohydrates which differ with regard to structural moiety and molecular mass. These carbohydrates, although non-toxic could serve as nutrients for the growth of many harmful microorganisms that cause various diseases of humans and aquatic life forms. Therefore, the soluble sugars need to be removed from the waste water prior to disposal to the environment. This research demonstrates the comparative photodegradation kinetics of monosaccharide, disaccharide, and polysaccharides by bare and Ag-TiO 2 depending upon their molecular weight and glycosidic linkages under UV irradiation. It revealed that Ag loading onto TiO 2 notably improved the photo-oxidation rates of sugar molecules to different hydroxylated intermediate photoproducts that ultimately decomposed to CO 2. Plausible degradation kinetics and mechanistic pathways for complete photomineralization of these sugars to CO 2 are briefly illustrated here by measuring optical rotation using polarimeter along with HPLC, GC and LC-MS analyses.