Zeolite Ammonia Removal from Catfish Pond Waters

摘要

The research focused on developing a zeolite filtration system which will prevent toxic ammonia build-up in catfish ponds. Zeolites are ion exchangers and some natural species are capable of selectively removing ammonia from various types of water systems. Six different species of natural zeolite, 36 samples total, were analyzed for ammonia cation exchange capacity (CEC) and slake-durability, which is the internal strength of material when placed in a liquid. Ideally, the most effective zeolite would have the highest ammonia CEC and the highest slake-durability index. The zeolite mineral clinoptilolite presently being mined at Death Valley Junction, California, was found to be the most suitable. The clinoptilolite has an average ammonia CEC of 218 milliequivalents per 100 grams and a slake-durability index of 98 percent. It also comes to equilibrium with ammonia in one day, has an exchange rate of 50 to 60 bed volumes per hour and can be regenerated in sodium chloride within 2 to 3 hours.