HCl modification and pervaporation performance of BTESE membrane for the dehydration of acetic acid/water mixture

Abstract

Membrane pervaporation has gained much attraction for high level purity of acetic acid from water because of energy saving and ecofriendly operation compared with distillation and extraction. However, fabricating membranes with high stability, selectivity and permeation flux for dehydration of acetic acid by pervaporation is highly demanded. In this work, hybrid silica membranes were fabricated using bis(triethoxysilyl) ethane (BTESE) as a precursor through sol gel route. Further modification was done as solid post HCl treatment for the synthesized BTESE membrane aiming to improve separation performance of the BTESE membranes for dehydration of acetic acid. The effect of HCl exposure time (30, 100, and 150 min) to the synthesized BTESE membranes was investigated to get optimum treatment conditions with lower separation tradeoff. In our investigation HCl treatment for about 100 min was found suitable in order to maintain permeation flux with higher selectivity. For the pervaporation performance to dehydrate acetic acid/water (90/10 wt%) at 80 °C, the synthesized BTESE membrane showed total flux of 2.47 kg m−2 h−1 with separation factor about 350 but HCl treated (100 min) BTESE membrane showed almost double separation factor up to 780 with somehow reduced flux (2.07 kg m−2 h−1). Both the membranes (synthesized and HCl treated BTESE) showed good stability within the investigated time of 150 h at 80 °C.