Patent ID: 7837880

Claim:
A method for recovering sulfuric acid from a feed mixture comprising sulfuric acid, hydrocarbons and water, the method comprising: processing said feed mixture that comprises from about 70 to about 98 percent by weight acid, using a crosslinked polymeric membrane comprising a crosslinked polyvinyl alcohol, a crosslinked polyvinyl sulfate, an oxoanion modified crosslinked polymerized polyvinyl alcohol, or a combination thereof, such membrane formed by an anhydrous process, to form a first retentate containing a substantially greater weight percentage of hydrocarbons than said feed mixture and a first permeate product containing a greater weight percentage of acid than said feed mixture, said crosslinked polymeric membrane being selectively permeable to the acid over the hydrocarbons in the feed mixture and further characterized as having a crosslinking density from about 1.0% to about 25.0%, and wherein the crosslinked polymeric membrane is crosslinked utilizing a crosslinking agent selected from the group consisting of 1,4 diisocyanatohexane, 1,4 diisocyanatobutane, 1,8 diisocyanatooctane, 1,12 diisocyanatododecane, 1,5 diisocyanato-2-methyl pentane, and 4,4′ diisocyanato-diphenylmethane.