Laser-enhanced photocatalytic degradation of organic pollutants from water using ZnO semiconductor catalyst

Abstract

Wastewater contaminated with organic pollutants creates serious environmental problems. Laser induced photocatalysis has been investigated for removal of organic pollutant like phenol from water. The important mechanism for degradation of phenol by UV laser irradiation is redox reactions triggered by semiconductor catalyst in presence of water. In this study the potential of a ZnO semiconductor catalyst has been explored as an effective catalyst for the photodegradation of phenol using a Nd:YAG laser-emitting at 355 nm in UV-radiation in a batch reactor. The influences of different parameters such as catalyst concentration, UV-radiation intensity, and pH on the extent of photo degradation have been investigated. Overall degradation of phenol achieved was 70% after 60 minutes of laser irradiation of 100 ppm phenol solution in water. The reaction rate constant fit a first-order reaction model for phenol degradation and was estimated as 0.0088 min(-1). This study proved that laser induced photocatalytic removal of phenol is highly efficient as compared with the broadband spectral sources such as lamps being applied in majority of setups worldwide.