NITRATE ANIONS REMOVAL FROM WATER USING SURFACE MODIFIED CLINOPTILOLITE

Nitrate anions removal from an aqueous medium using unmodified and modified clinoptilolite was carried out. The influence of different physicochemical parameters such as the initial ion concentration in the aqueous solution, pH, the clinoptilolite mass and the contact time, were investigated. Samples of natural clinoptilolite, taken from Rhodope Mountain in Bulgaria, have been modified with iron, magnesium and barium ions. The removal of nitrate anions efficiency was 73.58 %, 51.87 %, and 49.5 %, respectively. The removal efficiency of 46.93 % was achieved using unmodified clinoptilolite. The acidic pH did not influenced the removal efficiency. It was observed only slight decreasing of the modified with iron and magnesium ions clinoptilolite efficiency. The increasing of the removal efficiency (1.07 times) in the case of barium modified clinoptilolite, was negligible. The main nitrates removal was observed at the first minute of the process