FILTERS COMPRISING AN ACTIVATED CARBON PARTICLE COATED WITH PDADMAC AND METHODS OF MAKING SAME
Embodiments of systems and methods for producing a coated activated carbon comprise the steps of providing activated carbon particles having a particle size up to about 100 μm, and coating the activated carbon particles by spraying droplets of a cationic polymer solution onto the surface of the activated carbon particles, wherein the cationic polymer solution comprises about 1% to about 15% by weight cationic polymer and the droplet size is between about 5 μm to about 100 μm.
1 . A method for producing a coated activated carbon comprising:
providing activated carbon particles having an average particle size up to about 100 μm; and
coating the activated carbon particles by spraying droplets of a cationic polymer solution onto the surface of the activated carbon particles, wherein the cationic polymer solution comprises about 1% to about 15% by weight cationic polymer and the droplet size is between about 5 μm to about 100 μm.
2 . The method of claim 1 wherein the cationic polymer comprises polydiallydimethylammonium chloride (pDADMAC), polydiallydimethylammonium trifluoromethanesulfonate, (pDADMAT), or both.
3 . The method of claim 2 wherein the pDADMAC polymer comprises a weight average molecular weight (Mw) of up to about 200,000 g/mol and a number average molecular weight (Mn) of up to about 100,000 g/mol.
4 . The method of claim 1 wherein the cationic polymer solution comprises about 2% to about 8% by weight cationic polymer.
5 . The method of claim 1 wherein the cationic polymer solution comprises about 2% to about 4% by weight cationic polymer.
6 . The method of claim 1 wherein the coating step is conducted at a liquid pressure of about 20 psi to about 90 psi.
7 . The method of claim 1 wherein the coating step is conducted at an air pressure of about 60 psi to about 90 psi.
8 . The method of claim 1 wherein the droplet size of the cationic polymer solution is between about 15 to about 55 μm.
9 . The method of claim 1 wherein the droplet size of the cationic polymer solution is between about 20 to about 30 μm.
10 . The method of claim 1 wherein the coating of cationic polymer solution minimizes elution of cationic polymer by at least 60%.
11 . The method of claim 1 wherein the coating of cationic polymer solution minimizes elution of cationic polymer by at least 90%.
12 . The method of claim 1 further comprising drying the coated activated carbon particles.
13 . The method of claim 12 wherein the drying occurs at a temperature between about 70° C. to about 100° C.
14 . Coated activated carbon particle produced by the method of claim 1 .
15 . A filter comprising coated activated carbon particles as produced by the method of claim 1 .
16 . The filter of claim 15 wherein the coated activated carbons particles are in a carbon block filter.
17 . The filter of claim 15 wherein the coated activated carbons particles are formed into a carbon filter bed.
18 . The filter of claim 15 wherein the filter demonstrates a 6 log reduction of the bacteria RT and a 4 log reduction for the MS2 bacteriophage.
19 . The filter of claim 13 wherein the coated activated carbons particles are impregnated into a substrate media.
20 . The filter of claim 1 wherein the activated carbon particles comprise a median particle of less than about 100 μm.