Nickel removal from electroless nickel plating wastewater using chitosan-membrane filtration

Abstract

Nickel solution used in the plating process results in the contamination of the wastewater stream which is very hazardous and toxic to human, animal and the environment. Electroless nickel wastewater must be treated before being dumped into water bodies. Membrane filtration and adsorption have been widely applied in wastewater containing heavy metals. Adsorption process is the main treatment method and membrane filtration acted as a post treatment. Since adsorption is renowned as a promising technique in heavy metal removal, chitosan solution as an adsorbent showed higher advantages compared to chitosan flakes. The parameters studied were pH, adsorbent dosage and contact time and their optimum conditions were found to be 5.75, 2.11g/L, and 81 minute respectively obtained by using Response Surface Methodology (RSM) from STATISTICA v8.0. After treated by adsorption, the wastewater was filtered by Whatman filter paper and followed by membrane filtration while using the submerged hollow fiber system. The critical flux was determined by critical flux step and the operational flux used was flux four. The results show that, nickel removal was 95.18% when using adsorption. By integrating the two processes of adsorption-membrane filtration, nickel removal obtained was 98.27% and the adsorption process helped to reduce membrane fouling. For the isotherm and kinetics study in adsorption process, the experimental data were found to fit the Freundlich isotherm and Pseudo-second order kinetics. In conclusion, adsorption-membrane filtration process was found to be an effective treatment option for wastewater containing nickel.