AMMONIA REMOVAL FROM DRINKING WATER USING CLINOPTILOLITE AND LEWATIT S100.

摘要

High concentrations of ammonium in surface water make it unsuitable as drinking water, and thisis becoming a major problem in Europe, the United States, and other areas of the world. Thepurpose of this study is to investigate the possibility of removing ammonium from drinking water bymeans of an ion exchange process. We used one material of natural origin: clinoptilolite from theNi?ny Hrabovec locality in Slovakia (range 3-5 mm), and one synthetic material: Lewatit S100(range 0.3-1.2 mm). The weight capacity was determined by dynamic laboratory investigations, andwe investigated the influence of thermal pretreatment of clinoptilolite, and the percent of regenerates(2, 5, and 10% NaCl). The concentrations of ammonium ion inputs in the tap water that we usedwere 10, 5, and 2 mg NH4~+/l and down to levels below 0.5mg NH4~+/l. Experimental results showthat Lewatit S100 has almost 4 and 1.7 times weight capacity for ammonia removal compared to thecapacity of clinoptilolite for concentrations 10 and 5 mg NH4~+/l respectively, but for 2 mg NH4~+/l theweight capacity of clinoptilolite was found to be 1.9 times that of Lewatit S100. Heat pretreatment(400℃ for 6h) improved the zeolite’s selectivity for ammonium significantly. Ammonium removalcapacities were increased by approximately 40% and 20% for heat-treated zeolite samples. Theremoving concentration of Ca~(+2) and Mg~(+2) of clinoptilolite was lower than that of Lewatit S100. It isconcluded that the use of zeolite is an attractive and promising method for ammonium concentrationlower than 5 mg NH4~+/l but that Lewatit S100 is effective for ammonium concentrations greater thanthis level.