Development of high-performance and robust membrane via ‘hard-crosslinking-soft’ technique for dehydration of acetic acid

Abstract

Acetic acid, as one of the top 50 important chemicals, has been broadly applied for production of cellulose acetate, polyvinyl acetate, as well as synthetic fibers and fabrics, and so on. However, the acetic acid production always involves in water which should be removed. Thus, energy-efficient and environmental-friendly dehydration of acetic acid is highly required in current chemical industry. In this study, we proposed a ‘hard-crosslinking-soft’ strategy to construct a kind of organic-inorganic hybrid membrane by doping aminated silica (SiO2–NH2) nanoparticles into the polyelectrolyte complex (PEC) membrane for dehydration of acetic acid. The addition of SiO2–NH2 nanoparticles plays two roles: one is as the ‘hard’ part to overcome the over-swelling issue of ‘soft’ PEC membrane; another is creation of more free volume for water passing through. As a result, the proposed hybrid membrane could simultaneously augment the permeability and selectivity of the pervaporation membrane, breaking the notorious ‘trade-off’ restriction of separation membranes. The preparation parameters and operation condition on the performance of the membrane were detailed studied. The optimized membrane offers a flux of 1225 g/m2h and a separation factor of 1442 in dehydration of 10 wt% water/acetic acid mixtures at 50 °C, with pervaporation separation index of 1.77 × 106 g/m2h, among the top-tier separation performance. Besides, the prepared membrane could stably work for 144 h due to the chemical crosslinking by glyoxal, promising for the practical application for acetic acid dehydration.