Pretreatment of isopropanol solution from pharmaceutical industry and pervaporation dehydration by NaA zeolite membranes

NaA zeolite membranes with 80 cm in length and 12.8 mm in outer diameter were prepared by our research group cooperating with Nanjing Jiusi Hi-Tech Co., China. The influence of dissolved inorganic salts and pH value in the feed of isopropanol (IPA) solution on NaA zeolite membranes was investigated. It was found that both factors exhibited strong influence on the stability of NaA zeolite membranes. A set of pretreatment steps such as pH adjustment and distillation of the IPA solution were proposed to improve stability for pervaporation dehydration. An industrial-scale pervaporation facility with 52 m ² membrane area was built to dehydrate IPA solution from industrial cephalosporin production. The facility was continuously operated at 368-378 K to dehydrate IPA solution from water mass content of 15-20 to less than 2 with a feed flow rate of 400-500 L·h ^-1 and an average water flux of 1-1.5 kg·m ^-2·h ^-1. The successful application of this facility suggested a promising application of NaA zeolite membrane for IPA recovery from pharmaceutical production.