Enhanced and efficient removal of heavy metals by amino-decorated membranes in coordination with multi-function

A multi-functional MA/GMA@PVDF membrane with abundant amino groups was first prepared by grafting the intermediate with an epoxy group from glycidyl methacrylate (GMA) into a defluorinated polyvinylidene fluoride (PVDF) and subsequently conducting an ammonifying process with melamine. The highest pure water flux of the selected 0.2 %-MA/GMA@PVDF was up to 562 L/(m(2).h), with a high flux recovery ratio of 97.7 %, indicating excellent antifouling performance. Cu(II) concentration in the treatment volume of 47.44 L/m(2) met the discharge limitation of 0.5 mg/L, which was more than 5.3 times that of the PVDF membrane. The obvious enhancement was mainly attributed to the grafted amino groups, which could coordinate with Cu(II) with the lone-pair electrons. Moreover, inorganic salts and organic matter could improve 0.2 %-MA/GMA@PVDF rejection performance in mixed systems. Among them, NaNO3 could increase the effective treatment volume to 55.12 L/m(2) by charge shielding and compression double layer interaction owing to the unique property of amino groups. The maximum removal of Cu(II) by citric acid was increased by 48.63 % by the complexation of -NH2/-NH- groups. Thus, the multi-functional membrane decorated with amino groups shows great potential as a promising material to efficiently remove heavy metals from complex wastewater.