In-Situ Growth of Mof-Based Composites on Nylon Membrane for Effective Phosphate Removal

Abstract

A membrane adsorbent has been rationally designed to simplify the solid-liquid separation process and avoid adsorbent loss and leakage. MIL-100-Fe was grown in situ on the surface of nylon membrane substrates by layer-by-layer method, and the as-synthesized MIL@nylon was post-treated with sodium borohydride to generate iron (hydr)oxide nanoparticles within the MOF, named HFO@MIL@nylon. SEM, XRD and FT-IR were used to prove the successful loading of MIL-100-Fe and HFO@MIL on nylon substrate. The adsorption properties of HFO@MIL@nylon were tested. The results show that the adsorption process of phosphate accords with Langmuir and quasi-second-order kinetic model, with an adsorption capacity of 63.3 mg/g based on the mass of HFO@MIL. HFO@MIL@nylon could maintain high performance in a wide pH range. And the common interference ions SO42-, NO3-, Cl- only extended minus effect on the removal which means HFO@MIL@nylon has a good selectivity towards phosphorus. In addition, HFO@MIL@nylon membrane could work as a filter membrane, purifying 550 mL water of 200 μg/L with a flow rate of 1054 L/m2·h·MPa.

Keywords: Phosphate removal, Membrane adsorbents, MOFs, Hydrous iron oxide nanoparticles, Anti-interference