Diethylenetriaminepentaacetic acid (DTPA) grafted UiO-66-NH2/PES composite membrane for efficient removal of heavy metal ions

• A grafted UiO-66 was in-situ grown to fabricate UiO-66-NH 2 -g-DTPA/PES membrane. • The fabricated membrane captured HMIs via forming crab-like complexes. • The modified membrane shows high flux and high removal efficiency of multiple HMIs. • The obtained membrane remained excellent reusability for HMIs removal after 6 cycles. Heavy metal ion (HMI)-contaminated wastewater is a great threat to public health. Membrane separation is an efficient and green technology for HMI removal. Here, the strategy of nanoparticle in-situ growth combined with molecule grafting was proposed to fabricate the UiO-66-NH 2 -g-DTPA/PES composite membrane. The UiO-66-NH 2 nanoparticles bound within the PES membrane substrate uniformly brought a significant number of primary amino groups, providing abundant graft sites for DTPA molecule. Numerous carboxyl groups and tertiary amine groups were introduced as the result of DTPA grafting, enabling the formation of M−DTPA complexes with HMIs. The fabricated UiO-66-NH 2 -g-DTPA/PES membranes exhibited excellent performances. The pure water flux arrived at 6208 L·m −2 ·h −1 and the efficiencies of removing Cu 2+ , Pb 2+ , Cr 3+ and Cd 2+ were 99.73%, 99.79%, 96.91% and 98.33%, respectively. Moreover, the UiO-66-NH 2 -g-DTPA/PES membrane also showed a remarkable stability in pH conditions ranging from 3 to 10 and remained a relatively high performance in the cyclic test.