The technology is a fouling resistant nanofiltration membrane that filters out harmful contaminants from water and greatly reduces levels of hardness. The membrane is highly permeable and rejects divalent salts efficiently due to its unique water-channel architecture.
Nanofiltration is an important emerging technology for low-pressure, and therefore low-cost, industrial wastewater remediation. It allows for the removal of pesticide residues, harmful organic small molecules, and macromolecules. Nanofiltration is also valued for water purification and softening through the removal of divalent ions that harden water, while at the same time, retaining minerals that Reverse Osmosis (RO) would otherwise remove.
However, nanofiltration is not commonly used at industrial scales due to performance compromises originating in the broad pore size distribution that is inherent to current commercial membranes. Moreover, current nanofiltration membranes are expensive and need to be replaced periodically to prevent biofouling and chlorine degradation during cleaning.
Bicontinuous, single-nanometer water channel architecture enables efficient membrane filtration due to its very low internal hydraulic resistance. This membrane architecture is highly selective and permeable, and it rejects divalent ions and small molecules efficiently. The membranes are resistant to fouling and last longer in chemical cleaning agents.
This highly selective nanofiltration membrane is made by crosslinking a lyotropic liquid crystal based on a cationic surfactant. The quaternary ammonium in the polar head of the surfactant provides fouling resistance. Self-arrangement in columnar profiles allows single-nanometer water-bi-continuous transport. This leads to efficient nanofiltration with higher permeability and better solute selectivity.
Improved purification capability via small molecule and salt rejection
Superior hydraulic performance over 10 Lm2h-1bar-1
Fouling resistant and longer lasting membranes
Stage of Development:
Nanofiltration rejection efficiencies: (top) Dominant rejection of divalent ions in various salt solutions with a consistent ionic strength. PVDF supported membrane shows a higher rejection efficiency for all ions. (bottom) Plot depicts a quantitative performance evaluation of this membrane. The experiment is conducted at a constant transmembrane pressure with solutions containing NaCl (solid symbol) or MgCl2 (hallow symbol) as solutes. This membrane technology (H1) demonstrates hydraulic flux around 55 Lm-2h-1 and a rejection rate around 90%.