Parametric, equilibrium, and kinetic study of the removal of salt ions from Ghanaian seawater by adsorption onto zeolite X

Zeolite X was synthesized in the laboratory and was characterized using X-ray diffraction, scanning electron microscopy, thermogravimetric analysis, energy dispersive X-ray spectrometer, and Fourier transformed infrared spectrometry. Desalination activity of zeolite X was investigated by the ion-exchange process. The pH of the seawater prior to desalination analysis was 7.87 +/- 0.03 through the period of the investigation. The conductivity of the seawater was found to be 16.2 +/- 0.01 mS/cm. Effect of time on ion removal was measured. Removal efficiencies of ions showed a trend of Ca2+>K+>Mg2+>Na+. Equilibrium data were fitted by Langmuir and Freundlich isotherms and parameters were evaluated using these models. Adsorption capacities obtained followed the order Ca2+>K+>Mg2+>Na+ with R-2 values K+>Na+>Ca2+>Mg2+ for both Langmuir and Freundlich parameters. Equilibrium kinetic data were analyzed using adsorption kinetic models: pseudo-first-order and pseudo-second-order kinetic models. A linear regression method was used to estimate the adsorption and kinetic parameters. The R-2 values obtained followed the order K+>Mg2+>Ca2+>Na+ for both pseudo-first- and pseudo-second-order kinetic models. Zeolite X has attractive features as an adsorbent for desalination of seawater.