Exploiting the Different Parameters on the Adsorption of Phosphate Ions and Its Subsequent Recovery Using Complex Nickel–Aluminum–Zirconium Hydroxide

In this study, the effect of contact time, temperature, pH, and coexistences on the adsorption of phosphate ions using the complex nickel-aluminum-zirconium hydroxide (NAZ) was evaluated. Moreover, the recovery of adsorbed phosphate ions from NAZ using desorption solution with different concentrations was demonstrated. The results showed that the quantity of phosphate ions adsorbed gradually increased with time, and the adsorption equilibrium was achieved within 24 h after adsorption. This kinetic data could be well described by the pseudo-second-order model with the correlation coefficient in the value of 0.997. Additionally, the quantity of phosphate which was adsorbed increased as temperature increased, and these results corresponded well with both the Langmuir, the correlation coefficient ranged from 0.920-0.949, and Freundlich models, the correlation coefficient ranged from 0.863-0.995. These results showed that the adsorption of phosphate ion was monolayer adsorption onto the NAZ surface. The optimal pH for removal of phosphate ions from aqueous media was during 4-8. In addition, chloride, nitrate, and sulfate ions did not significantly affect to the adsorption capability of phosphate ions in the complex solution system. Finally, the phosphate ions which were adsorbed onto NAZ could be recovered using sodium sulfate solution (recovery percentage: approx. 50% using sodium sulfate solution at 1000 mmol/L). These results highlight the potential of using NAZ as the cost-effectiveness adsorbent for phosphate ions removal from aqueous media.