Study on the adsorption of Ce(III) on phosphonic acid functionalized ZIF-67@SiO2 magnetic porous carbon materials

Abstract

A ZIF-67 composite SiO2 material (ZIF-67@SiO2) was synthesized using ethyl orthosilicate (TEOS) as a silicon source, followed by one-step carbonization to produce magnetic porous nitrogen-doped carbon material (MNPC@SiO2) using ZIF-67@SiO2 as a carbon precursor. Subsequently, the composite P-MNPC@SiO2 was obtained through functionalization with diethylphosphonoethyltriethoxysilane (DPTS), and its characteristics were analyzed. The adsorption properties of Ce(III) on MNPC@SiO2 and P-MNPC@SiO2 composites were investigated under various conditions through adsorption experiments. Kinetic, isothermal, and thermodynamic models were employed to analyze the adsorption mechanism of P-MNPC@SiO2 on Ce3+ and assess adsorbent stability and regeneration performance. The result shows that P-MNPC@SiO2 exhibited excellent adsorption capacity for Ce3+ and possessed magnetic properties conducive to recycling. Under optimized conditions, P-MNPC@SiO2 reached Ce(III) adsorption saturation within 20 min, with a maximum adsorption capacity of 342.52 mg/g, which was 1.9 times higher than that of the MNPC@SiO2 material. Data fitting shows that surface adsorption controls the rate-limiting step, and Ce(III) forms a monolayer adsorption on the surface of the adsorbent material. Furthermore, P-MNPC@SiO2 exhibits strong stability and regeneration properties.