A novel polyzwitterionic hydrogel coated mixed matrix membrane (MMM)was successfully prepared, characterized and used for Cu2+,Mn2+, and Pb2+heavy metal ions removal from water. Hydrophilic and porous covalentorganic framework (COF) nanoparticles (NP) as filler were synthesized frommelamine and terephthalaldehyde, and then incorporated into polyamide (PA)thin film composite (TFC) membrane. The hydrogel coating was applied byusing a tailored cross-linkable polymer system in combination with concentra-tion polarization enabled cross-linking. The effects of COF NP loading into PAlayer and polyzwitterionic hydrogel coating on the membrane morphologyand separation performance were studied using different analyses. The MMMprepared with a COF NP loading of 0.02 wt/wt% in the hexane dispersion usedfor NP deposition during PA layer formation (leading to 0.42 g/m2) exhibitedan increased pure water permeability of around 200% compared with the neatPA TFC membrane while the Mn2+ion rejection maintained above 98%. Scan-ning electron microscopy surface images and zeta potential profiles showedthat the hydrogel was successfully deposited on the membrane surface. Fur-thermore, the hydrogel coating could decrease net surface charge of mem-branes but did not significantly influence the heavy metal ions rejectionsunder nanofiltration conditions. The results of filtration experiment with pro-tein solution indicated that the hydrogel coated membranes exhibited superiorantifouling property, as shown by higher flux recovery ratio after washing withwater, compared with neat PA TFC membrane and not coated MMM,respectively.

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