Modified polyvinylidene fluoride membranes for water filtration
AssigneeUchicago Argonne, LLC
InventorsJeffrey W. ELAM, Bratin SENGUPTA
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Abstract
A process for modifying polyvinylidene fluoride (PVDF) membranes for water filtration includes contacting the membrane with a solution of hydroxide in water at a temperature of about 65° C. to about 85° C. for about 0.5 hours to about 24 hours to form a pretreated membrane. The process also includes depositing a coating on the pretreated membrane by an ALD process to form a modified membrane. The depositing includes (A) contacting the pretreated membrane with a precursor gas to form a precursor complex on a surface of the pretreated membrane; and (B) contacting the pretreated membrane with a co-reactant, the co-reactant reactive with the precursor complex.
Claims20
A method comprising:
- contacting a membrane comprising polyvinylidene fluoride (PVDF) with a solution comprising about 4 N to about 10 N hydroxide in water at a temperature of about 65° C. to about 85° C. for about 0.5 hours to about 24 hours to form a pretreated membrane;
- and
- depositing a coating on the pretreated membrane by a vapor-phase deposition process to form a coated membrane, the depositing including:
- (A) contacting the pretreated membrane with a precursor gas to adsorb or form a precursor complex on a surface of the pretreated membrane;
- and
- (B) contacting the pretreated membrane with a co-reactant, the co-reactant reactive with the adsorbed precursor gas or precursor complex.
A membrane comprising:
- polyvinylidene fluoride (PVDF) with pores formed therein having a diameter of about 10 nm to 10 μm;
- and
- a metal oxide coating disposed on the PVDF, the metal oxide coating having a thickness of about 0.1 nm to about 20 nm;
- wherein the membrane has a water permeance of about 1000 L·m−2·h−1·bar−1 to about 1300 L·m−2·h−1·bar−1 and a flux recovery of about 80% to about 99.9%.
A method of filtering an aqueous liquid comprising:
- passing the aqueous liquid through a membrane at a permeance of about 1000 L·m−2·h−1·bar−1 to about 1300 L·m−2·h−1·bar−1;
- backwashing the membrane;
- and
- after backwashing, passing the aqueous liquid through the membrane again with a flux recovery of about 80% to about 99.9%.
Dependencies are inferred from the claim text.