Reduction of Nitrogen Load in a Zootechnical Wastewater Using a Natural Chabazite Zeolite: An Investigation on Sorption Mechanisms

The use of zeolite-rich tuffs is a valid method for recovering nitrogen from wastewaters. This paper aims at describing the NH4+ adsorption processes of an Italian chabazite zeolite tuff used for the treatment of raw liquid swine manure. The effects of temperature, grain size and contact time were investigated. The isothermal analysis showed a multilayer adsorption behavior, well explained by the Harkins–Jura model, while kinetics was explained by pseudo-second-order, Elovich and intraparticle diffusion models. This study highlighted the complexity of the adsorption process from raw liquid manure, as well as the significant differences between tested particle sizes of the same zeolite tuff.