GO/MoS2/PEI composite membrane for removin salt ions from water

Separation membranes based on graphene oxide (GO) have attracted much attention due to their good separation properties. But its instability in water and rejection of divalent salt ions is a problem that needs to be solved urgently. In this study, molybdenum disulfide (MoS 2 ) is intercalated into graphene oxide by adding polyethyleneimine (PEI) solution drop by drop for cross-linking, and then GO/MoS 2 /PEI composite membrane is prepared by vacuum filtration. As MoS 2 hydrophobicity increases frictionless water flow channels to improve water flux, PEI cross-linking improves membrane stability and rejection of divalent salt ions. The modified composite membrane has a high rejection of 94.8 % for Mg 2+ , and water flux is increased by 30 % relative to GO/PEI membrane. In addition, the rejection of the composite membrane to different salt solutions is investigated by MgCl 2 , MgSO 4 , NaCl and Na 2 SO 4 solutions, and the results obtained are, in order, R(MgCl 2 ) > R(MgSO 4 ) > R(NaCl) > R(Na 2 SO 4 ). This modified composite membrane has great potential for salt ion removal.