Pervaporation crystallization for simultaneous organic solvent recovery and induced nucleation from pharmaceutical crystallization wastewater.

Pharmaceutical crystallization wastewater typically contains high concentrations of valuable active pharmaceutical ingredients (APIs) and organic antisolvent. The current approach to treating this wastewater stream, while effective for environmentally benign disposal, could be further developed to enhance its resource recovery potential. Herein, pervaporation crystallization (PVCr) and the specific membrane were developed to simultaneously achieve the organic solvent recovery and induced crystal nucleation. The fabricated membrane, owing to its superior intrinsic hydrophilicity, significantly reduces the critical nucleation energy barrier and creates high local supersaturation via preferential water permeation. With the ideal nucleation condition on the membrane surface, effective ethanol enrichment provided a gentle driving force for crystal growth, leading to high-quality, non-agglomerated single crystals (d = 1.42 μm, CV = 24.45 %) with a 94 % yield at 30°C and 1 atm. These fine crystals are ideal for direct seeding into the traditional crystallizer. Recovered high-purity ethanol and water streams are suitable as antisolvent and solvent in the production section, respectively. According to process simulation results, PVCr reduced operating costs by 60.7 %, thereby improving environmental performance by avoiding the energy-intensive separation process of repeatedly vaporizing and condensing the reflux. These results demonstrate that the PVCr assembled with customized functional membrane possesses great potential for treating multi-component organic wastewaters.