A new sand adsorbent for the removal and reuse of nickel ions from aqueous solutions

Nickel ions (Ni(II)) in aqueous solutions was removed by a sand absorbent with a surface functionalized porous coating. The sand absorbent has a very large surface area of 150 m2/g. The influence of pH, initial concentration of the solution, temperature, contact time and absorbent dosage on the removal efficiency of the synthesized sand absorbent toward Ni(II) in the aqueous solutions were studied. The results indicate that the adsorption of nickel onto the sand absorbent greatly increases the pH range of 2–4 and slightly increases with the temperature from 25 to 40 °C. The maximum removal efficiency and ion retention in per unit mass of the absorbent were 100% and 5.78 mg/g, respectively, under the specified experimental conditions. The adsorption can be described by the pseudo-second-order kinetic model and the Freundlich adsorption model. The adsorbed nickel (4.24 mg/g) together with the spent absorbent was successfully employed to prepare a brown glass, suggesting a new way to the reutilization of the recovered nickel from wastewater and to avoid the secondary pollution caused by the used absorbents.