The study of reverse osmosis on glycerin solution filtration: Dead-end and crossflow filtrations, transport mechanism, rejection and permeability investigations

• This work studied water separation from glycerin solution using RO membranes.
• Dead-end and crossflow filtrations were employed in this study.
• Physicochemical property of the membranes affected their rejection and permeate flux.
• TFC-HR in the crossflow filtration achieved the glycerin rejection up to 99.81%.
• The possible molecular movement and transport across the membrane were postulated.

The utilization of recycled water from reverse osmosis (RO) filtration within a production process can be one of the potential solutions to conserve fresh water. In this work, the effect of membrane physicochemical properties on glycerin rejection and water permeability were demonstrated in dead-end and crossflow filtrations. The study showed that RO membrane with high surface roughness, high negative charge in glycerin solution, low water contact angle, high water affinity and small pore radius were favorable in glycerin separation. Crossflow filtration provided better rejection and permeability than that of dead-end filtration using the RO membranes studied in this work. The combination of fundamental knowledge on membrane physicochemical properties and boundary layer theory was used to speculate the molecular movement and transport mechanism across the membrane. The highest rejection of 99.81% was achieved by TFC-HR membrane, along with the permeate flux of 11.86 kg/m2·h in the crossflow filtration while in the dead-end filtration, only a rejection of 96.37% and permeate flux of 4.93 kg/m2·h were recorded. Lastly, it was found that the membrane surface pattern influenced the membrane performance significantly in terms of rejection and permeability.