Abstract
This review discusses the application of bridged–organosilica membranes in ultra–high–pressure reverse osmosis (RO) for concentrating organic aqueous solutions, notably dimethylformamide (DMF) in wastewater. RO process offers a more energy–efficient alternative to traditional distillation, but it faces challenges such as high osmotic pressure and the need for durable membranes. The first half of this review summarizes the development of porous ceramic RO membranes with high selectivity and chemical stability, suitable for operating at high–pressure and high solvent concentration. These membranes, with their unique silica networks with organic bridging groups, demonstrate high rejection performance not only in aqueous system but also in solvent–solvent separation. The second half of this review introduces the multi–stage ultra–high pressure filtration process for concentrating organic aqueous solutions. A key innovation in the multi–stage process is to develop and combine high–rejection RO and lower–rejection nanofiltration (NF) membranes. The combination use of RO and NF enables efficient concentration at lower pressures. The simulation study indicates that a well–optimized process significantly reduces energy consumption and represents an effective solution for sustainable resource use.
