Thin-Film Nanocomposite (TFN) Membranes Incorporated with Super-Hydrophilic Metal–Organic Framework (MOF) UiO-66: Toward Enhancement of Water Flux and Salt Rejection

Abstract

Zirconiumv (IV)-carboxylate metal-organic framework (MOF) UiO-66 nanoparticles were successfully synthesized and incorporated in the polyamide (PA) selective layer to fabricate novel thin-film nanocomposite (TFN) membranes. Compared to unmodified pure polyamide thin-film composite (TFC) membranes, the incorporation of UiO-66 nanoparticles significantly changes the membrane morphology and chemistry, leading to an improvement of intrinsic separation properties due to the molecular sieving and superhydrophilic nature of UiO-66 particles. The best performing TFN-U2 (0.1 wt % particle loading) membrane not only shows a 52% increase of water permeability but also maintains salt rejection levels (∼95%) similar to the benchmark. The effects of UiO-66 loading on the forward osmosis (FO) performance were also investigated. Incorporation of 0.1 wt % UiO-66 produced a maximum water flux increase of 40% and 25% over the TFC control under PRO and FO modes, when 1 M NaCl was used as the draw solution against deionized water feed. Meanwhile, solute reverse flux was maintained at a relatively low level. In addition, TFN-U2 membrane displayed a relatively linear increase in FO water flux with increasing NaCl concentration up to 2.0 M, suggesting a slightly reduced internal concentration polarization effect. To our best knowledge, the current study is the first to consider implementation of Zr-MOFs (UiO-66) onto TFN-FO membranes.

Thin Film Nanocomposite Membrane Filled with Metal-Organic Frameworks UiO-66 and MIL-125 Nanoparticles for Water Desalination

“…Findings showed that the water flux increased by 44% comparing to the plain membrane by adding 0.05% MIL-101 NPs to the organic solution, while the salt rejection remained almost the same. Similar outcomes were observed by Ma et al [58] when embedding UiO-66 in membranes used in forward osmosis. By loading 0.1% NPs to the membrane, the water flux increased from 2.19 to 3.33 LMH/bar.…”

A thin film nanocomposite membrane with pre-immobilized UiO-66-NH2 toward enhanced nanofiltration performance

“…As a prototype Zr-MOF, UiO-66 has displayed interesting physical and chemical characteristics for the preparation of highly water-stable MOF membranes for liquid separation. [22][23][24] The highly regular structure of UiO-66 with the aperture size of about 6.0 A, 25,26 which is located between H 2 O (2.6 A) and hydrated ions (e.g. Na + 7.2 A, Mg 2+ 8.6 A, SO 4 2À 7.6 A, Cl À 6.6 A), is promising for achieving high ux and sustains high salt rejections by ionic sieving.…”

High Adsorption Pearl‐Necklace‐Like Composite Membrane Based on Metal–Organic Framework for Heavy Metal Ion Removal

“…Synthetic approaches for composites of MOFs and scaffolds mainly include: (1) directly fill MOFs particles in matrices and the composite membranes are fabricated by solution casting approach. While this extensively applied method has two main problem: one crucial issue is the inevitable agglomeration of MOFs particles and the other is the adhesion of MOFs on matrices needs to be enhanced; (2) tether polymer monomers onto MOFs particles, and utilize the copolymerization process to integrate both together; (3) in situ growth on scaffolds via solvothermal growth in precursor or microwave irradiation, whichever is chosen, it can avoid the agglomeration of MOFs particles and ensure the strong link between MOFs and scaffolds . Thus integrating MOFs with membrane materials via in situ growth seems to be a more promising strategy.…”