Hydrothermal synthesis of a novel nanolayered tin phosphate for removing Cr(iii)

Abstract

In this work, an outstanding nanolayered tin phosphate with 15.0 Å interlayer spacing, Sn (HPO₄)₂·3H₂O (SnP–H⁺), has been synthesized by conventional hydrothermal method and first used in the adsorptive removal of Cr(III) from aqueous solution. A number of factors such as contact time, initial concentration of Cr(III), temperature, pH, and ionic strength on adsorption were investigated by batch tests. Moreover, the isothermal adsorption characteristics and kinetic model of Cr(III) onto SnP–H⁺ were studied. The results showed that the adsorption of Cr(III) by SnP–H⁺ was in accordance with the Langmuir adsorption isotherm model and the pseudo-second-order kinetic model. The adsorption capacity of Cr(III) onto SnP–H⁺ at temperature 40.0 °C and pH 3.0 could reach 81.1 mg g⁻¹. And the distribution coefficient K_d was 23.0 g L⁻¹. Overall, experiments certified that SnP–H⁺ was an excellent adsorbent that can effectively remove Cr(III) from aqueous solution.