Semiconductor-mediated photocatalyzed degradation of erythrosine dye from wastewater using TiO_2 catalyst

摘要

A semiconductor photocatalytic process has been studied extensively in recent years because of its intriguing advantages in environmental remediation. The kinetic studies of the adsorption and degradation phenomenon involved in the photocatalytic degradation of erythrosine were investigated using a batch reactor and artificial UV light. Experiments were performed in a suspended TiO_2 system at pH 5.7 and mass catalyst 0.08 g/L. Adsorption is prerequisite for the TiO_2-assisted photodegradation, and the extent of degradation has been discussed in terms of the Langmuir-Hinshelwood model. Like most semiconductors, the photocatalytic nature of TiO_2 is pH dependent because of its amphoteric nature. It is found that under the influence of TiO_2 as catalyst the coloured solution of the dye erythrosine becomes colourless, and the process follows first-order reaction kinetics. The adsorption trends of erythrosine at various initial concentrations followed the Langmuir isotherm trend. Measuring chemical oxygen demand (COD) also monitors the toxicity of the degraded dye solution and a significant decrease is observed, which implies that photodegradation through TiO_2 is a safer technique.