Application of amine-functionalized MCM-41 modified ultrafiltration membrane to remove chromium (VI) and copper (II)

Abstract A thin-film composite ultrafiltration (UF) membrane grafted with amine-functionalized MCM-41 was prepared and used for removing heavy metals from aqueous solution. The porous NH 2 -MCM-41 nano-particles formed a uniform hydrophilic and adsorptive layer on the thin-film which endowed the composite membrane with affinity to heavy metals and better anti-fouling performance. The adsorption capacity of Cr (VI) and Cu (II) on membrane were 2.8 mg Cr/g and 3.7 mg Cu/g, respectively, and their adsorption processes reached equilibrium around 5 min. The continuous UF experiments demonstrated that the membrane can be used as an effective filter medium to purify the water containing trace heavy metals. The metals concentration in filtrates was maintained below initial concentration of 1 mg/L (Cu) and 0.5 mg/L (Cr) during the 7-hour filtration. The membrane’s adsorption capacity could be regenerated by being immersed in 0.5 M HNO 3 . Besides, to examine its anti-fouling performance, the model NOM (natural organic matter) water was used as a feed solution. The composite membrane showed not only slower irreversible fouling evolution but also higher rejection of NOM compared with that without grafting NH 2 -MCM-41. The method reported in this study was efficient to enhance the rejection and anti-fouling performance of UF membrane, what’s more, endowed the membrane with affinity to heavy metals.