Performance evaluation of chitosan-zinc oxide nanocomposite thin films in refinery wastewater treatment

Abstract

The current research aims to develop a natural polymer based nanocomposite film using low molecular weight chitosan and zinc oxide nanoparticles (ZnO NPs) for the removal of pollutants from refinery wastewater. The ZnO NPs have been synthesised by modified sol gel technique. The nanocomposite thin films have been fabricated using dip coating method by immersing a glass substrate into the chitosan -nanoparticle composite. The refinery wastewater treatment is carried out using the fabricated composite film by altering the processing conditions of wastewater pH, exposure time, speed of agitation and the number of deposition layers and the best treatment conditions are established. The SEM micrographs of composite thin films exhibited excellent surface morphological behaviour of the nanocomposite. The AFM topographic image demonstrated the nanoscale formation of thin films. From the experimental studies performed with the composite thin films for the treatment of refinery wastewater, the best performance was achieved at pH 8.0, 60 min of contact time with 10 layers of thin-film deposition, and a stirring speed of 100 rpm. The outcome of the study demonstrates that the nanocomposite thin films developed from chitosan and ZnO NPs has a promising pollutant removal capacity in the refinery wastewater treatment.