Kinetic and thermodynamic studies of the ammonium ions adsorption onto natural Algerian bentonite

Abstract

Adsorption processes are the most recommended complementary techniques applied in the wastewater treatment owing to their low economic cost, recyclability, efficiency and low power consumption. Clays known for this treatment are aluminosilicate minerals which contain different exchangeable ions on their surfaces. In the structure of bentonite surface, several cations have the exchange ability such as calcium, sodium, magnesium and potassium. This propriety is responsible for the adsorption of several cationic water pollutants. In this study, natural bentonite particles of 80 μm in diameter were considered and kept stirring at 200 RPM in a contaminated solution with ammonium ions. The effect of contact time and temperature showed that at an optimal temperature of 30°C and during a short stirring time of 50 min, the removal efficiency could reach its maximum of 53.36%. The kinetic study of the ammonium adsorption reaction on natural bentonite allowed concluding that the reaction is obeyed to the first-order model. Determination of various thermodynamic parameters suggests that the reaction is spontaneous and exothermic