Performance of Sulfonated Polysulfone RO Membranes Against Organic Foulants

Outline Introduction Classes of Membrane Materials Sulfonated Polysulfone Reverse Osmosis Membranes Opportunities to add value Summary Next Steps “Fixing the desalination membrane pipeline” McCutcheon and Mauter, Science, April 2023, vol 380 issue 6642 “The status quo of overselling a membrane made at millimeter scale and promoting an unrealistic narrative about how it will change water treatment must end.” Cellulose Acetate Asymmetric RO Membranes Salt Rejection 95-98% Moderate chlorine tolerance Poor resistance to compaction Manufacturing: 1. Roll to roll solvent casting and phase inversion process “Cellulose Acetate Reverse Osmosis Membranes for Desalination: A Short Review, Shuo Liu, Liling Hu, W. Zhang, Hang Ma, Non-Metallic Material Science, Oct. 2019 “Optimization of the evaporation step in cellulose acetate membranes preparation by dry-wet phase inversion technique for water desalination applications, Amier S. Polyamide Thin Film Composite RO Membranes Salt Rejection 98-99.8% Poor chlorine tolerance Good resistance to compaction Higher Flux/Lower Energy Manufacturing: 1. Sulfonated Polysulfone Thin Film Composite RO Membranes SPSF Separation Layer Microporous support Non-woven support Salt Rejection 94-99% Excellent chlorine tolerance Good resistance to compaction SO M Higher Flux/Lower Energy O O O S O O S O S O x 1-x Manufacturing: O O O 1. Comparative Membrane Properties EPA Limit in Drinking Water (411 ppm NaCl) Chlorine Membrane Exposure Material Rating 1, Polyamide ppm-hrs Cellulose 10, Acetate ppm-hrs Sulfonated 200, Polysulfone ppm-hrs Eliminate Biofouling with NALA Membranes Strong Oxidant/NaOCl Source Water Pump Pre-Treatment Reverse Osmosis Clean Water Less Energy Less Cleaning and Maintenance 24% Opex Savings Longer Membrane Lifetime Salt Rejection as a Function of pH Polyamide Sulfonated Polysulfone polyamide membranes fail lose salt rejection at extremes of pH Flat sheet crossflow test cells, Run in 2000 ppm NaCl at 220 psi Sulfonated Polysulfone Membrane Scale-up and Commercialization Plans Spiral wound membranes currently in development at 1812 scale 40” membrane sheet scale-up planned for Q2/Q3 2024 40” spiral wound membranes planned for Q3/Q4 2024 Use case demonstrations currently in development Exploring pilot opportunities Summary and Acknowledgements Sulfonated polysulfones are a new class of reverse osmosis membrane, soon to be commercialized Outstanding chlorine stability, differentiated rejection characteristics, and low fouling characteristics offer unique opportunities for treating challenging feed sources In progress scale-up efforts will provide 2540, 4040, and 8040 spiral wound membranes by end of 2024. Developing use case demonstrations to lead to pilots www.nalamembranes.com.