(82d) Synthesis and Application of Multi-Carboxyl Compound As a Novel Draw Solute in Forward Osmosis Process

The forward osmosis (FO) process has attracted growing research interest as an alternative water-treatment technology for its low energy consumption and high contaminant rejection. However, the limited choice of suitable draw solution is still an obstacle in the commercial development of FO technology. In this work, a multi-carboxyl compound-ethylenediaminetetrapropanoic acid (EDTP acid) has been synthesized via the Michael addition reaction and employed as a novel draw solute in FO process. The as-synthesized structure is confirmed by FTIR, NMR, and HRMS. By proper optimizing the pH of EDTP acid solution, the solubility and the osmotic pressure can be effectively improved. The FO performance with EDTP acid/salts as draw solutes is evaluated, and the results suggest that water flux and salt flux both increase with the increasing solute concentration. A high water flux of 22.36 LMH could be achieved with 0.8mol/L EDTP solution as draw solution and deionized water as feed solution through a HTI-CTA FO membrane in the pressure-retarded osmosis mode. Clearly, EDTP acid is superior to most traditional draw solutes for its much less draw solute leakage with a comparable water flux in the FO process. The pressure-driven NF process was also employed to regenerate the diluted draw solution effectively.