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)
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In this study, the photochemical degradations of three commonly used artificial sweeteners, namely aspartame (ASP), acesulfame K (ACE), and sucralose (SUC) were investigated in multicomponent aqueous systems through UV/H2O2. A recirculating batch photochemical reactor setup was utilized for experimental work. The treatability of the multicomponent system was monitored in the form of total organic carbon (TOC) reduction. A two-level fractional factorial design of experiments (DOE) was adopted. The individual and multifactor interaction effects of the concentration of the three sweeteners, the applied hydrogen peroxide dosage and the operating temperature on TOC reduction were investigated. The biodegradability characteristics of the sweeteners were investigated for both single and multicomponent systems through respirometry. Their degradations were compared to those of the UV/H2O2 system. It was determined that the UV/H2O2 process is suitable treatment technique, achieving TOC removal efficiencies over 90% with a UV exposure of 45 min. The operating temperature and the applied H2O2 dosing on the final TOC removal were found to be significant. An interaction between ASP and SUC resulted in a temporary improvement in TOC removal midway through the treatment process. Respirometric studies confirmed that ACE and SUC are non-biodegradable. The biodegradation characteristics of ASP was found to be acceptable with a 6-day biochemical to theoretical oxygen demand (BOD6/ThOD) ratio of 0.63±0.02. I would also like to thank engineering specialists Mr. Ali Hemmati and Mr. Daniel Boothe of Ryerson University's Department of Chemical Engineering for providing their support and assistance throughout my work. I would also like to thank the members of my research team, Melody Johnson, Yi Ping Lin, Ciro Bustillo-Lecompte and Mohsen Nasirian for their help and guidance. I would also like to thank my dear friends
Hydrolysis of disaccharides containing glucose residue in subcritical water
Biochemical Engineering Journal, 2004
The hydrolysis of disaccharides consisting of two glucose residues or of glucose and fructose or galactose residues in subcritical water was measured using a tubular reactor at 10 MPa and 180-260 • C. The relationship between the fraction of remaining disaccharide and the residence time could be expressed by the Weibull equation for all the disaccharides tested at any temperature. The susceptibility to hydrolysis largely depended on the type of disaccharide, and it was found that the electrostatic potential charge of a glucosidic oxygen atom was an indication for the susceptibility of disaccharide to the hydrolysis. It was also shown that the enthalpy-entropy compensation held for the hydrolysis of disaccharides in subcritical water.