A New Perspective of Nanofiltration Membrane to Reconcile Challenges in Treating and Recycling High Salinity Brine

A New Perspective of Nanofiltration Membrane to Reconcile Challenges in Treating and Recycling High Salinity Brine Xiaofei Huang, PhD; Craig R. Bartels, PhD March 6, 2024 8: AM-8: AM Session: WED-4-Pushing the Boundaries of Energy Efficiency: Advancements in Membrane Technologies From RO to NF Brine Concentrator Membrane (BCM) Approach P = NDP + DP + P + Δπ feed perm CC Lower rejection membrane reduces osmotic pressure difference, requires less driving pressure The boundary Limit of NF in treating high salinity brine. A Value Change Related to Pore-Flow Mechanism Low SP RO High SP NF Wang, L., et al. (2023), “Water Transport in Reverse Osmosis Membranes is governed by Pore Flow, not a Solution-Diffusion Mechanism”, Science Advances, Vol 9, No.15. Practical Salinity Range A Value Restriction B Value Restriction 50,000 – 250,000 mg/L (NaCl based solution) TDS Change Salt Separation Selectivity Multivalent ion rejections are higher and less influenced by TDS change. Monovalent ion rejections reduce significantly with TDS increase. Case Study- Copper Mine Wastewater Feed TDS 99738 Na Cl Ca Mg 6116 Cu 1516 Fe 1457 Al 7488 Zn SO4 80650 F 2178 Recovery 50% Case Study- Textile Wastewater ZLD Treatment Project Recycle SO4 rich Brine Case Study- Higher concentrated SO4 rich brine Textile Wastewater achieved 17% OPEX reduction. Conclusion Through high salinity mix ion test, various rejection and permeability NF membranes were characterized. YES, NF membranes offer new solutions in treating high salinity brine. Suggested treatable TDS range 50,000 – 250,000 mg/L Water chemistry matters Case specific and treatment goal specific A value and B value play together as restriction factors on NF treating high salinity solution. (reasonable range of A and B value selection) Pore flow transport mechanism explains well our observations. A value and B value characteristics of NF change with TDS.