This study provides a facile and effective method to modify thin film composite (TFC) hollow fiber
nanofiltration (NF) membranes by grafting poly (amidoamine) dendrimer (PAMAM) on the interfacially
polymerized layer of polyethersulfone (PES) membranes for heavy metal removal. The PAMAM grafting
not only decreases the pore size of the composite membrane, but also provides the positively charged
functional groups, such as tertiary amino groups (RH3Nþ and R3HNþ), on the membrane surface to
improve the hydrophilicity and water permeability of the TFC membrane without compromising
rejection. The resultant membrane possesses rejection over 99% against most tested heavy metals like
Pb2þ, Cu2þ, Ni2þ, Cd2þ, Zn2þ and As5þ, with an outstanding pure water permeability (PWP) greater
than 3.6 L m2 h1 bar1 at 10 bar. The rejection of the membrane to As3þ is also impressive. It can
reach 97% by changing the solution pH. Moreover, the membrane shows stable performance for at least
72 h under continuous testing. This PAMAM grafted TFC membrane may have great potential for heavy
metal removal and other water treatment applications.
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