The best alternatives to Purify Blocker are BlockBear, Adblock Fast, and Truman Grade. If these 3 options don't work for you, we've listed a few more alternatives below.
Adblock Fast is a new, faster ad blocker and the first open-source ad blocker for iOS (http://appadvice.com/appnn/2015/09/adblock-fast-is-a-free-and-open-source-way-to-banish-ads-in-ios-9)!
Just as webpages grew bloated with ads, so too have ad blockers grown bloated with little-used filtering rules and features that sap their speed and hog your device’s disk space, CPU cycles, and memory.