Ceramic supported attapulgite-graphene oxide composite membrane for efficient removal of heavy metal contamination

Abstract

Ceramic supported graphene oxide (GO)/Attapulgite (ATP) composite membrane (GOA) was simply prepared by vacuum filtration for efficient removal of heavy metal contamination. The ATP nanorods were incorporated within the laminar layers of GO, influencing the interlayer distance and facilitating greater number of channels for enhanced water transportation. The GOA possessed greater surface wettability with improved water flux rate of 6.3 L m−2 h−1 compared to 0.4 L m−2 h−1 measured for its pristine counter-part. The GOA demonstrated excellent rejection efficiency (nearly 100%) for heavy metal ions such as Cu2+, Ni2+, Pb2+ and Cd2+. The excellent separation efficiency of GOA could be ascribed to the synergic combination of size exclusion effect based on the formation of 3D network structures between the GO layers and increased electrostatic interaction in between the negatively charged surface moieties of GOA and heavy metal ions. More importantly, the use of Al2O3 as a support substrate resulted in improved stability and allowed extended usage of the membrane for a period of 3500 min while maintaining 99% rejection efficiency for Cu2+ ions. The high flux rate, great water stability and prominent rejection capability of the designed membrane is suggestive of its practical application in removal of heavy metal contamination from water.