Nitrate removal from model aqueous solutions and real water by calcined Mg/Al layered double hydroxides

Magnesium/Aluminium-carbonate layered double hydroxides were synthesized by two coprecipitation methods in conditions at low and high supersaturation with consequential calcination and application for nitrate removal. The different parameters such as adsorbent dosage, contact time, pH were observed in model solutions with various content of nitrates from 100 to 200 mg/L to adjust optimal conditions for removal of nitrates from real water. The well water contained exceeded concentration limits of nitrates as well as cations such as magnesium, calcium, manganese and iron according to the required quality of drinking water. Nitrate concentration below the toxicity limit value was reached with removal efficiency of 72% and 84.6% for the first stage of adsorption by using of 15 and 20 g/L of calcined adsorbent dose, respectively. In the second stage of adsorption after elimination of cations as well as coexisting anions in the first stage, the removal efficiency of nitrates was higher of 73.9%, 94.7%, 98.7% and 99.2% for calcined adsorbent dose from 5, 10, 15 and 20 g/L, respectively.