(152ae) Poster: In-Situ Metal-Organic Frameworks Membrane Surface Functionalization for Water Treatment: Synthesis, Characterization, and Performance.

Metal-Organic Frameworks (MOFs) have attracted significant attention in the last decade for their high surface area, porosity, tuneability, etc. These unique properties make them highly desired materials in gas storage, adsorption, catalysis, etc. The grafting of MOFs on the surface of membranes, immobilization of MOFs inside of a selective layer of thin-film composite membranes or mixing MOFs inside the membranes have been reported using pre-formed MOFs. In both methods, the aggregation of MOFs is a challenging issue. In this project, we report the in-situ synthesis and growth of ZIF-8 and Ag MOFs on a Polyethersulfone (PES) ultrafiltration and TFC membrane using ultrasonication method. The ultrasonication method synthesizes MOFs using only environmentally friendly solvents (such as ethanol and water), room temperature reaction with no damage to membrane, and short time (5-60) mins. We hypothesize that surface functionalizing the MOFs on a membrane could render facilitated water transport, adsorption of the specific pollutants, and designed size exclusion properties through MOF’s nano-pores benefit both higher selectivity and flux. We used polydopamine (PDA) as a bridging agent between the PES and MOFs because polydopamine can adhere to the polymeric substrates, and its catechol (-OH) group forms co-ordinate covalent bonding with the metal node of the MOFs, offering better attachment. The blank PES UF membrane exhibited water permeability 25 LMH/Bar with 3 % MgSO4 salt and 9% methyl orange (MO) dye rejection. The PES-PDA membrane were fabricated at two different dopamine coating time of 5 h and 24 h. The PES-PDA- 5h showed pure water permeance of 10 LMH/Bar with increased 11 % salt rejection and 8% MO Dye Rejection. PES-PDA-24 h showed pure water permeance of 2 LMH/Bar with 26 % salt Rejection and 30 % MO Dye rejection. We currently are examining the stability of the synthesized MOFs to ensure longer (>48 h) operation without leaching of MOFs and enhanced rejection of salt and dyes.