Phosphate removal from aqueous solutions by using natural Jordanian zeolitic tuff

In this study, a naturally occurring zeolitic tuff located in Jordan was investigated as a potential adsorbent for phosphate removal from aqueous solution. Adsorption kinetics and thermodynamics of phosphate adsorption under different temperatures were studied. The pseudo-second-order kinetic model adequately fitted the collected experimental data under different initial ion concentrations. The Langmuir model is found to be successfully fitting the experimental data. Thermodynamic parameters such as Gibbs?s free energy change, standard enthalpy change, and entropy change were evaluated and the results indicated that the sorption process is spontaneous, exothermic with small degree of randomness during the sorption process.