Nanocomposite membrane for simultaneous removal of dye and heavy metal ions from wastewater

A catalytic 2D nanocomposite membrane (CNC) was fabricated and used for the simultaneous removal of methylene blue (MB) and heavy metal ions in aqueous solution. Both molybdenum disulfide (MoS2) and graphene oxide (GO) were incorporated in a chitosan polymer matrix, and the fabricated CNC membrane exhibited performance as a nanofiltration membrane. Here MoS2 activated H2O2 to generate very reactive oxygen species (ROS), such as hydroxyl radicals, allowing the catalytic breakdown of the organic dye contaminants and reducing heavy metal ions. Greater than 99% efficiencies were achieved for the simultaneous removal of methylene blue (MB) and the heavy metal Co2+. Moreover, significant removal efficiencies in the 89-96% range were demonstrated for other heavy metal ions of Cu2+, Pb2+, and Ni2+. The generated ROS were trapped by terephthalic acid (TA) and confirmed by fluorescence emission spectroscopy. The used membrane was regenerated and reused with a flux recovery rate of more than 91% after 4 experimental cycles. These promising results indicated that the novel catalytic 2D nanocomposite membrane showed a high potential for the simultaneous removal of organic contraminants and heavy metal ions from textile industry wastewater.