Insight into the adsorption behavior and mechanism of trace impurities from H₂O₂ solution on functionalized zirconia by tuning the structure of amino groups

Primary, secondary and tertiary amino-functionalized zirconia (ZrO₂−NH₂, ZrO₂−NH and ZrO₂−N) was synthesized by the postgrafting method for the adsorption removal of typical metallic ions, phosphate and total oxidizable carbon from a real H₂O₂ solution. ZrO₂−NH₂, ZrO₂−NH and ZrO₂−N exhibited similar pore sizes and sequentially increased zeta potentials. The adsorption results of single and binary simulated solutions showed that the removal efficiency increased in the order of Fe³⁺ > Al³⁺ > Ca²⁺ > Na⁺. There is competitive adsorption between metallic ions, and Fe³⁺ has an advantage over the other metals, with a removal efficiency of 90.7%. The coexisting phosphate could promote the adsorption of metallic ions, while total oxidizable carbon had no effect on adsorption. The adsorption results of the real H₂O₂ solution showed that ZrO₂−NH₂ exhibited the best adsorption affinity for metallic ions, as did phosphate and total oxidizable carbon, with a total adsorption capacity of 120.9 mg·g⁻¹. Density functional theory calculations revealed that the adsorption process of metallic ions involves electron transfer from N atoms to metals and the formation of N-metal bonds.