ARGET ATRP based surface-imprinted polymer-ordered mesoporous silica composites for selective chloramphenicol adsorption

Abstract This study introduces a novel approach for synthesising a surface-imprinted polymer-ordered mesoporous silica adsorbent, known as SiO 2 @MIPs-CAPcr, with high selectivity for chloramphenicol (CAP) adsorption by employing an activator that was regenerated by electron atom transfer radical polymerisation (ARGET ATRP). Optimal synthesising conditions for SiO 2 @MIPs-CAPcr have been determined, including catalyst ratios, reaction temperature, and reaction time. The prepared silica initiator (SiO 2 @Br) was confirmed using XRD, SEM, and HRTEM, which revealed uniform spherical nanoparticles with a high specific surface area (638.31 m 2 .g −1 ) and total pore volume (0.4152 cm 3 .g −1 ). FTIR, TGA, TEM, and XRD analyses confirmed successful grafting of the MIPs layer onto SiO 2 @Br, which reduced the surface area and pore volume of SiO 2 @MIPs-CAPcr. Under optimised batch adsorption conditions, as analysed using the Sips model, the maximum chloramphenicol (CAP) adsorption capacity of 19.68 mg.g −1 was observed, following a pseudo-second order kinetic model, with thermodynamic analysis indicating a spontaneous, exothermic process. SiO 2 @MIPs-CAPcr displayed high selectivity for chloramphenicol (CAP) over thiamphenicol (TAP) and ciprofloxacin (CIP), along with a minimal 6.87% decrease in adsorption capacity after four regeneration cycles, demonstrating both strong specificity and good reusability. These findings highlight the effectiveness of ARGET ATRP in engineering tailored adsorbents for environmental and pharmaceutical applications. Graphical Abstract