Synthesis of high-performance biocompatible polymeric membranes incorporated with zirconium-based MOF for an enhanced brackish water RO desalination

Abstract

Abstract A nanosized zirconium 1,4- dicarboxybenzene metal-organic framework (UiO-66-MOF) was synthesized and impregnated into cellulose acetate (CA) polymeric matrix to enhance the membrane characteristics for brackish water desalination. Phase inversion was used for the fabrication of CA/UiO-66 hybrid membranes (CAU-X), where X is the concentration of immobilized UiO-66 nanoparticles (UiO-66-NPs) into CA polymeric matrix. Morphological structure and functional groups were investigated through different characterization techniques to prove the successful synthesis of the prepared UiO-66-NPs, the blank CA membrane, and hybrid CAU-X membranes. For more CAU-X characteristics, porosity, contact angle, and tensile strength were measured. The obtained data demonstrated that the impregnation of zirconium-based-NPs had a positive influence on the blank CA membrane properties. Additionally, the performance of the fabricated membranes was investigated in reverse osmosis (RO) bench-scale unit. The performance results for the pristine CAU-0 membrane showed a high salt rejection (SR) of 99.8% and a permeate water flux (PWF) of 1.14 L/m 2 .h. In comparison to pristine CA membrane, CAU-X hybrid membranes have a slightly lower SR and a higher PWF. It was found that the hybrid CAU-0.02 membrane had almost a doubled PWF of 2.8 L/m 2 .h with only 2% sacrificed SR of 97.6% compared with CAU-0 membrane. Moreover, a much better PWF of 3.4 L/m 2 h and a sufficient SR of approximetly 92% were obtained by CAU-0.05 membrane. Thus, CAU-0.05 was selected to further test its performance under different operating parameters. Results revealed that the optimum parameters were recorded for a sodium chloride feed stock of 5000 ppm operating at 25 °C temperature and pressure up to 15 bar. Graphical Abstract