CHEMICAL AND PHYSICAL CHARACTERIZATION OF A TIO2-COATED FIBER OPTIC CABLE REACTOR

Practical application of metal oxide photocatalysts for the remediatio n of contaminated wastestreams often requires immobilization of the ph otocatalyst in a fixed-bed reactor configuration that allows the conti nuous use of the photocatalyst by eliminating the need for post-proces s filtration. A novel optical fiber cable reactor (OFR) is used to tra nsmit UV light to solid-supported TiO2 in order to investigate the pho tocatalytic degradation of pentachlorophenol (PCP), 4-chlorophenol (4- CP), dichloroacetate (DCA) and oxalate (OX). The distribution of light as a function of fiber diameter and the quantum efficiencies as a fun ction of incident light intensity are investigated. Light propagation down individual fibers is found to in crease with increasing fiber dia meter. An in creased linear transmission of light results in increased quantum efficiencies, while a P-order of magnitude reduction in incid ent light intensity results in a 4-fold increase (phi = 0.010-0.042) i n quantum efficiency for the degradation of 4-chlorophenol. The rates of degradation of dichloroacetate and oxalate have strong pH dependenc ies. Relatively high apparent quantum efficiencies of phi = 0.010, 0.0 15, 0.08, and 0.17 for PCP, 4-CP, DCA, and OX, respectively, and compl ete mineralization to CO2, H2O, and HCl are observed in the OFR system .