Pervaporation performance of PPO membranes in dehydration of highly hazardous mmh and udmh liquid propellants

•Polyphenylene oxide (PPO) membranes were synthesized for dehydration of highly hazardous MMH and UDMH liquid propellants.•Effect of feed concentration, membrane thickness and permeate pressure on permselectivity was investigated.•A molecular modeling technique for determination of diffusion coefficients of MMH, UDMH and water through PPO membrane is presented.•Molecular dynamics simulation is coupled with CFD for analyzing the hydrodynamic scenario during pervaporation. Polyphenylene oxide (PPO) membranes synthesized from 2,6-dimethyl phenol monomer were subjected to pervaporation-based dehydration of the highly hazardous and hypergolic monomethyl hydrazine (MMH) and unsymmetrical dimethyl hydrazine (UDMH) liquid propellants. Membranes were characterized by TGA, DSC and SEM to study the effect of temperature besides morphologies of surface and cross-section of the films, respectively. Molecular dynamics (MD) simulation was used to study the diffusion behavior of solutions within the membrane. CFD method was employed to solve the governing mass transfer equations by considering the flux coupling. The modeling results were highlighted by the experimental data and were in good agreement. High separation factors (35–70) and reasonable water fluxes (0.1–0.2kg/m2h) were observed for separation of the aqueous azeotropes of MMH (35wt%) and UDMH (20wt%) and their further enrichment to >90% purity. Effect of feed composition, membrane thickness and permeate pressure on separation performance of PPO membranes were investigated to determine optimum operating conditions.