Acid-Modified ZnO Nanoparticles Embedded Polysulfone Membranes for Separation of Copper from Industrial Wastewater

Abstract

Copper is one of the crucial materials for the biological activity of human beings and is known for antimicrobial properties during wound management. Hence its presence in the effluent is overlooked although it is reported to be detrimental at higher concentrations. Its effect on humans varies from simple dizziness, diarrhea to liver/kidney damage, etc. Various techniques are reported for separation of these toxic pollutants from effluent. This article focuses on development of polysulfone-based membranes with use of additives: polyethylene glycol (PEG) and ZnO nanoparticles (NPs) (nascent and modified with HCl) for separation of copper from effluent by Donnan Exclusion principle. The incorporation of acid treated ZnO NPs in membrane matrix provides surface charge to membrane. This results in repulsive interaction with copper salts from process which retained in retentate as per Donnan exclusion principle. The membrane formed with 40% PSF- 0.8% ZnO NPs shows the rejection of copper up to 40%, which raises to 61% when instead of nascent NPs, HCl treated NPs were used. The rejection efficiency of the membrane raises up to 90% when PEG was used along with PSF and ZnO NPs (acid treated). The use of modified NPs in membrane matrix has strong impact on membrane morphology and rejection efficiency. The modification of surface charge properties and morphological distribution of NPs is supported by FTIR and EDX. Further the separation works upon physical distribution of NPs, which would help to maintain the stability properties of PSF based membrane enhancing its applicability in actual process conditions.