Efficient removal of heavy metal ions based on the optimized dissolution-diffusion-flow forward osmosis process

In order to efficiently remove the heavy metal ions in wastewater, a novel thin film composite (TFC)-type forward osmosis (FO) membrane was prepared specifically with the glass nanofiber supporting layer and the bovine serum albumin (BSA)-embedded polyamide (PA) swellable active layer, and used for the removal of heavy metal ions from water by enhanced dissolution-diffusion-flow FO process. The separation results indicated that the appropriate addition of BSA in the PA active layer improved the dissolution-diffusion process of the traditional PA layer by providing the swellable sites as water channels in aqueous solutions and enhanced the rejection effect on heavy metal ions. In addition, the ultra large porosity and pore size of the glass nanofiber supporting layer provided smooth flow channels, accelerating the flow process and alleviating the concentration polarization problem, with the structural parameter (S) value decreasing to 172 μm. This paper proved that the specific structural construction of the functional membranes was a convenient method to prepare applicable membranes with tunable FO performances.