Photochemical Degradation of Aqueous Artificial Sweeteners by UV/H2O2 and Their Biodegradability Studies
thesisposted on 22.05.2021, 10:20 by Ramtin Jahani
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.