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.