title: Effects of hydrogen peroxide feeding strategies on the photochemical degradation of polyvinyl alcohol.
abstract: The performance of batch and fed-batch photoreactors with that of continuous photoreactor for the treatment of aqueous polyvinyl alcohol (PVA) solutions is compared. Hydrogen peroxide feeding strategies, residence time, and [H2O2]/[PVA] mass ratio are examined for their impacts on the molecular weight distribution (MWD) of PVA and the total organic carbon (TOC) removal. The results prove that a continuous addition of H2O2 during the degradation reaction ensures the utilization of the produced radicals to minimize the oxidant consumption and maximize the TOC removal and the PVA degradation in a short irradiation time. Also, the MWD of PVA is found to be bimodal and shifted towards lower molecular weights with small shoulder peak indicating a progressive disappearance of the higher molecular weight fractions that is in accordance with the random chains scission mechanism. Besides, the hydrogen peroxide feeding strategies are found to have a great effect on the reduction in H2O2 residuals in the effluent.
authors.affiliation: a Department of Chemical Engineering , Ryerson University , Toronto , Canada.
authors.forename: Dina
authors.initials: D
authors.lastname: Hamad
authors.affiliation: a Department of Chemical Engineering , Ryerson University , Toronto , Canada.
authors.forename: Ramdhane
authors.initials: R
authors.lastname: Dhib
authors.affiliation: a Department of Chemical Engineering , Ryerson University , Toronto , Canada.
authors.forename: Mehrab
authors.initials: M
authors.lastname: Mehrvar
mesh_terms: D006861:Hydrogen Peroxide / Q000737:chemistry*; D055668:Photochemical Processes; D011142:Polyvinyl Alcohol / Q000032:analysis / Q000737:chemistry* / Q000528:radiation effects; D014466:Ultraviolet Rays; D062065:Wastewater; D018508:Water Purification / Q000379:methods*
chemical_list: D006861:Hydrogen Peroxide; D011142:Polyvinyl Alcohol; D062065:Wastewater
keywords: Polyvinyl alcohol; TOC removal; UV/H2O2 process; continuous photoreactor; hydrogen peroxide feeding; molecular weight distribution