Synthesis of CeO2@SiO2 nanocomposites for adsorption of Cu(II) and Pb(II): insights from batch and column studies

Abstract

CeO2@SiO2 nanocomposites were synthesized via rotary evaporation and co-precipitation for efficient removal of Cu(II) and Pb(II) from aqueous media. Among the tested compositions, CeSi-3 (CeO2:SiO2 = 1:0.5) exhibited the best performance, achieving maximum adsorption capacities of 160 mg/g for Pb(II) and 138 mg/g for Cu(II) at pH 6. Adsorption followed a pseudo-second-order kinetic model and fit the Langmuir isotherm. Desorption was successfully performed using both diluted HCl and 0.01 M EDTA. HCl achieved complete desorption of Pb(II) and 86% for Cu(II), while EDTA reached 97% for Pb(II) and 85% for Cu(II), with both maintaining the structural integrity of the adsorbent. Only a slight decrease in adsorption efficiency was observed after 10 regeneration cycles using HCl and after 3 cycles using EDTA, confirming the excellent reusability of the material. In fixed-bed column studies, CeSi-3 showed similar breakthrough capacities of around 60 mg/g for both metal ions, well-described by the Thomas model. These findings demonstrate that CeO2@SiO2 nanocomposites are efficient, reusable, and chemically stable adsorbents for sustainable water purification applications.