BACKGROUNDMulti-walled carbon nanotubes (MWCNTs) have attracted considerable interest in the membrane field, but they are prone to aggregate in the polymer matrix and cause membrane defects. Different from blending MWCNTs in the casting solution, different ratios of APTS-functionalized MWCNTs (A-MWCNTs) were embedded on the surface of polyvinylidene fluoride (PVDF) membranes. RESULTSFTIR and XPS demonstrated the reaction between MWCNTs and APTS. SEM and AFM images showed that new morphology and pore structure appeared in novel A-MWCNTs/PVDF membranes compared with pure PVDF membrane. The embedding was firm because of APTS chains penetrating into the PVDF matrix, and the optimum content of A-MWCNTs was 0.05 wt%. Besides, A-MWCNTs/PVDF membranes exhibited superior contact angle and BSA rejection than PVDF membrane. In the tests of copper ions rejection and adsorption, 0.05 wt% A-MWCNTs/PVDF membrane gave 89.1% removal and 2.067 mg g(-1) adsorption capacity compared with PVDF membrane, at just 19.66% and 0.516 mg g(-1), respectively. CONCLUSIONSThe existence of functional groups in A-MWCNTs such as -NH2 and -COOH, can not only increase the hydrophilicity of membranes, but also provide more adsorption sites to have a complexation reaction with Cu2+ ions. This work provides information to solve practical problems in the field of wastewater treatment. (c) 2015 Society of Chemical Industry