Adsorption of ammonia nitrogen by riverbank filtration system and influencing factors

Quality water purification of riverbank filtration system is an important guarantee for water safety in the water treatment process．A primary water source in Harbin is the Songhua Riverbank Source．Here the ammonia nitrogen adsorption-removal characteristics at different depth of aqueous media layers in static adsorption batch tests were analyzed, with effects of initial concentration, temperature, pH at different aqueous medium layer studied．Adsorption of ammonia nitrogen at different depths was found to conform to a quasi-second-order kinetic model and Langmuir model．The adsorption was of monolayer adsorption, controlled by chemical action．With increasing depth, adsorption capacity decreased, but water purification capacity decreased．Adsorption amount was positively correlated with initial concentration．Adsorption of \rmNH^+_4 was exothermic, inhibited by increasing temperature．With increasing pH, the competitive adsorption between H⁺ and \rmNH^+_4 decreased, surface electronegativity of aquifer media increased, leading to increased adsorption capacity of \rmNH^+_4 ．In neutral environment at 10℃, adsorption and removal was the best．