Hybrid Membranes Fabricated By Incorporating Molecular Sieves With Hierarchical Pores For Pervaporative Desulfurization

Pervaporation is a membrane separation technology which has found importance in industrial applications and is the subject of ongoing research.Pervaporation has advantages such as high efficiency,low energy consumption,and low pollution.The high-performance membrane materials are the key to achieving large-scale industrial applications and reducing costs.There are two major essential factors in judging the quality of a membrane:selectivity and permeation flux.The construction of well-structured channels within the membranes is an effective approach to enhance the mass transfer properties,thereby improving the performance of the membranes.This study aims to construct continuous channels in the membranes to optimize the desulfurization performance towards model gasoline.The main results are summarised as follows:MCM-41 particles were introduced into Polyether-block-amide(Pebax)matrix to prepare hybrid membranes.Hierarchical pores in the MCM-41 particles with micropores(1.5 nm)and mesopores(3.5 nm)are used to construct continuous channels in the hybrid membranes,in order to decrease the diffusion resistance and increase the permeation flux.At the same time,the separation performance of the hybrid membrane is improved by the solution-diffusion process.When the content of MCM-41 was 4wt%,the permeation flux of the hybrid membrane is 21.97 kg/(m~2 h),and the enrichment factor is 6.75.The hybrid membranes have displayed excellent thermal stability,anti-swelling performance,good separation performance at high temperatures and excellent long-term operation stability.SBA-15 particles have microporous(0.57-0.62 nm)and mesoporous(6-6.5 nm)hierarchical structure.When the SBA-15 particles are incorporated into Pebax matrix,the size of the micropores channels within the SBA-15 imparted the molecular sieving effect ensuring the selectivity of the penetrant molecules(thiophene),while the mesopores construct a continuous channel for rapid transport of penetrant molecules in the membrane.When the content of SBA-15 in the hybrid membrane was 6 wt%,the membrane-displayed and optimum permeation flux of 22.07 kg/(m~2 h)and an enrichment factor of 6.76.The membranes have excellent long-term operation stability.