Synthesis of nanostructured NiO and its application in laser-induced photocatalytic reduction of Cr(VI) from water

Owing to its high toxicity, chromium(VI) is considered as top priority pollutant for many countries in the world and removal of this pollutant from waste water is highly desirable. The present investigation addresses the synthesis of NiO nanoparticles using sol-gel method and their application in heterogeneous photocatalytic reduction of Cr(VI) using a 355 nm laser radiation generated from Nd:YAG laser. The study showed that similar to 90% Cr(VI) was removed within short laser exposure time (75 min) in presence of nanostructured NiO without the use of any additive as reported in other studies. Effect of critical parameters, such as calcination temperature, calcination time, laser energy, catalyst amount, chromium concentration, and added electron donor and acceptor on the photocatalytic reduction process was investigated. The photocatalytic reduction of metal was found to be strongly dependant on the above mentioned parameters. (C) 2011 Elsevier B.V. All rights reserved.