Ammonium removal from landfill leachate using natural zeolite: kinetic, equilibrium, and thermodynamic studies

Abstract

AbstractThe scope of this study is to research the removal of NH4-N from landfill leachate using natural Turkish zeolite by adsorption process. The effects of pH (2–8), contact time (5–1,440 min), adsorbent dosage (30–150 g L−1), agitation speed (100–300 rpm), initial concentration (263.2–1,363.6 mg L−1), and particle size (10–65 mesh) were examined on the adsorption process. The optimum conditions in the adsorption process were established as follows: pH (its pH value of leachate), 60 min of contact time, 100 g L−1 of adsorbent dosage, 200 rpm of agitation speed, 263.2 mg L−1 of initial concentration, and −20 + 35 mesh of particle size. The adsorption kinetics and isotherms were tested to understand the adsorption mechanism using three kinetic models, i.e. Elovich, intraparticle diffusion, the pseudo-second-order reaction kinetic models, and four isotherm models, i.e. Dubinin–Radushkevich, Langmuir, Tempkin, and Freundlich isotherm models. Correlation coefficients, kinetic, and isotherm parameters were c...