Degradation of the persistent organic pollutant-lindane in fixed-bed photoreactor packed with immobilized Zinc Oxide and Iron oxide-doped Zinc Oxide photocatalysts

The potential for the photocatalytic degradation of lindane, used as agricultural insecticide and pharmaceutical product, is investigated. Two types of photocatalysts, immobilized on 5 mm sodalime beads are synthesised using an easy and economical process: (1) Zinc Oxide (ZnO) nanoparticles and (2) Iron oxide-doped Zinc Oxide (Fe-ZnO). Tests of lindane degradation under continuous flow conditions are conducted on a stainless steel fixed bed photoreactor using a 6W UV-A lamp operating at 375 nm. The lindane sorption onto photocatalysts is examined with equilibrium and kinetic tests at batch mode. The experimental datasets are fitted with a 1-dimensional advection-dispersion-sorption-reaction numerical model to estimate the parameters controlling the lindane degradation rate: the apparent sorption capacity of the catalyst, and the surface reaction kinetic constant. Based on estimated parameter values, a comparative analysis of the performance of the two catalysts is done.