Development of high‐flux aciduric ultra‐thin nanofibrous pervaporation composite membrane for acetic acid dehydration

Acetic acid is an essential intermediate chemical in industry. Traditional inorganic membrane cannot meet the demand of high-efficient dehydration and polymeric membrane is restricted by its low organic solution resistance. In this work, a novel aciduric pervaporation composite membrane was successfully generated by fabricating an ultrathin polysulfonamide (PSA) layer on the polyacrylonitrile (PAN) nanofibrous substrate via interfacial polymerization (IP) method. Through the optimization of fabrication process including selecting the suitable structure of diamine (taking three types aliphatic amines as candidates), optimizing the concentration of two phase solutions, the resultant thin-film nanofibrous composite (TFNC) membrane was fabricated by using aliphatic amine triethylenetetramine (TETA: 3.0 wt%) and 1, 3-benzenedisulfonyl chloride (BDSC: 1.0 wt%) as IP monomers and the network structure with suitable sieving size was constructed. The ultrathin aciduric PSA selective layer (thickness: 104 ± 15 nm) endowed the TFNC membrane with excellent separation efficiency. For dehydrating 70 wt% acetic acid aqueous solution at 60°C, PSA-3.0-1.0/PAN TFNC membrane exhibited competitive separation efficiency and great acid stability. It possessed extremely high permeate flux (15,321 g/m2 h) with stable separation factor (109). For long-term acid dehydration evaluation, PSA/PAN membrane showed great stability during 7 days pervaporation. This work took advantage of traditional IP method for designing a novel pervaporation membrane with aciduric chemical structure, suggested an effective and facile approach to develop novel pervaporation membranes for harsh environment separation.