Synthesis of MIL-101 supported on ceramic membrane for organic solvent nanofiltration

The purpose of this study is using an in-situ assisted acetic acid procedure to prepare a MIL-101 as filler in ceramic membrane. The MIL-101 membrane is firstly applied for organic solvent nanofiltration. In this study, the effects of synthetic conditions are investigated to get an invisible defect membrane and nanofiltration performance is also checked to prove the feasible application of MIL-101 membrane. Incorporation of metal organic framework (MIL-101) as filler on ceramic membrane is firstly investigated. In-situ method assisted by acid modular is utilized to synthesize uniform and defect-free MIL-101 membrane. Effect of additives such as NaOH, HF, CH3COOH and concentration of reactants are surveyed to find out the optimal synthetic conditions. Synthesis of MIL-101 membrane by using in-situ acetic acid-assisted method is proved as efficient way to prepare a compact and dense MIL-101 layer compared to other methods as thermal seeding method, layer by layer seeding method. The MIL-101 membranes are characterized by using a variety of different techniques, including X-ray thin film diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy EDX. MIL-101 is chosen as material filler for membrane in nanofiltration application because of its ability to form the largest pore size in the MOFs’ family and a number of its prominent properties for molecular separation applications such as high surface area and well-defined pore size. Besides, MIL-101 and ceramic substrate are inorganic materials, so they are able to be stable in harsh solvent such as N-methyl-2-pyrrolidone (NMP), dimethyl sulfoxide (DMSO), dimethylacetamide (DMAc), those usually dissolve common polymers. The MIL-101 membranes are applied in organic solvent nanofiltration (OSN) by testing separation of Rose Bengal (RB) from NMP, DMSO, DMAc and ethanol. The MIL-101 membranes show a significantly high rejection but lower permeance compared to bare ceramic membrane. The best flux and rejection of MIL-101 membrane with RB ethanol solution are 1.65 lm-2h-1bar-1 and 99.7% respectively where ratio of chromium nitrate, benzendicarboxylic acid and water is 1:1:277, respectively and 0.8 ml of CH3COOH. The MIL-101 membranes also exhibit the stability under harsh solvent with high rejection of RB and constant flux within 3 hours.