Adsorption mechanism of recovering potassium from seawater by modified-clinoptilolite using microwave

The adsorption capacity and mechanism of Kthorn ion onto modified-clinoptilolite (MC) for recovering potassium from seawater has been investigated in this paper. The maximum value of K+ adsorption capacity is 36.3 mg/g (1.92 times of raw-clinoptilolite) while the modifying condition of microwave power is 450 W and heating time is 60min. Specific surface area and pore size of absorbent has also been advanced with employing microwave. The kinetic data followed the pseudo-second-order model kinetic model, and the equilibrium data were well fitted to the Langmuir model, showing monolayer coverage of K+ ions on the surface pores of MC. Thermodynamic parameters, including Gibbs free energy (Delta G), enthalpy changes (Delta H), and entropy changes (Delta S) were also calculated. The results demonstrated that K+ ion was absorbed onto MC spontaneously and exothermically in nature. Thus, MC could be employed as efficient and suitable adsorbent for recovering potassium from seawater.