Amino-functionalised silica-grafted molecularly imprinted polymers for chloramphenicol adsorption

Abstract

This research investigated the liquid-phase removal of chloramphenicol (CAP), an emerging contaminant using molecularly imprinted polymers (MIPs). CAP adsorption profiles, equilibrium, and kinetics were analysed. The adsorption performance was compared between MIPs and non-imprinted polymers (NIPs), both with silica or without silica grafting. The imprinting factor (IF) values for the Si@MIPs-CAP were significantly higher than the IF values for MIPs-CAP adsorbent at pH 8. The kinetics of CAP adsorption was fitted to pseudo-second-order kinetics models for MIPs-CAP (R2 = 0.9998) and Si@MIPs-CAP (R2 = 0.9999). The adsorption isotherm of Si@MIPs-CAP was well represented by the Langmuir model (R2 = 0.9991), while the Freundlich isotherm model (R2 = 0.9998) provided the best fit for MIPs-CAP. The maximum monolayer adsorption capacities, Qmax, for Si@MIPs-CAP (32.26 mg g-1) were higher than the Qmax for Si@NIPs-CAP (29.6 mg g-1). These results suggested that the silica-grafted molecularly imprinted polymers can be employed as a potential water-compatible adsorbent for the selective adsorption and removal of CAP from aqueous phase.