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Reduce Biofouling of Reverse Osmosis Membranes by Surface Modification. Abhijit Sarkar, Adrian Merrington, Joseph L. Rousseau, Tracy Zhang, Apurba Chakrabarti, Peter I. Carver, Beena Thomas, Steven E. Keinath and Petar R. Dvornic. Michigan Molecular Institute. Midland, MI. Abstract.
Abhijit Sarkar, Adrian Merrington, Joseph L. Rousseau, Tracy Zhang, Apurba Chakrabarti, Peter I. Carver, Beena Thomas, Steven E. Keinath and Petar R. Dvornic
Michigan Molecular Institute
The applications for Reverse Osmosis (RO) are numerous and varied. Desalination of seawater or brackish water for drinking purposes, wastewater recovery, food and beverage processing, biomedical separations, purification of home drinking water and industrial process water are some of these applications. However, membrane fouling caused by the growth of bacteria on the membrane surface often leads to significant permeate flux decline and loss of product quality in RO systems. Thus, prevention of biofouling of RO membranes has become most imperative. MMI has developed a unique coating system for RO membranes that make the surface extremely hydrophilic. This, in turn, provides protection of the RO membranes from biofouling. Most importantly, the increase in antifouling property via surface modification does not compromise the permeate flux and salt rejection efficiencies of the membranes.
Membranes have small pores that will plug and blind off instantly, unless they are run in the crossflow mode.
Four categories of membranes defined on the basis of size of the materials they can remove from the carrier liquid.
Reverse osmosis (RO)
Extensive use of desalination will be required to meet the needs of a growing world population.
Desalination Technology Energy Requirement
Reverse Osmosis (RO; 44%) 4.7-5.7 kWh/m3
Multi-Stage Flash distillation (MSF; 40%) 23-27 kWh/m3
Time Versus Flux
Commercial RO Membranes
Evaluation of FilmTec RO Membranes for Selectivity and Flux
Rejection rate versus time at 100 psi and 250 psi for (a) LE and (b) XLE membranes
Flux versus time at 100 psi and 250 psi for (c) LE and (d) XLE membranes
Fouling by model colloids:
20 nm and 110 nm
SEM photomicrograph of an LEmembrane coated with HBP-PEG network.
SEM photomicrograph of an uncoated LE membrane.
Hydrophilicity, flux and selectivity of surface modified FimTec membranes
Flux and salt rejection for FilmTec’s LE RO membrane, surface modified with HBP-PEG polymer network coating. Average values of dynamic membrane properties from 5 measurements were obtained at 100 psi.
Flux and salt rejection for FilmTec’s XLE RO membrane, surface modified with HBP-PEG polymer network coating. Average values of dynamic membrane properties from 5 measurements were obtained at 100 psi.