Removal and tracing of cephalosporins in industrial wastewater by SPE-HPLC: optimization of adsorption kinetics on mesoporous silica nanoparticles

Abstract Cephalosporins are β-lactam antibiotics which are considered the most widely used for humans and animals in many countries. Solid phase extraction was applied using Oasis HLB cartridges for tracing three cephalosporins (cefadroxil, cefprozil, and cefradine) in industrial wastewater samples. Sample extraction was followed by chromatographic analysis. The developed high-performance liquid chromatographic method was used for the determination of these selected cephalosporins. Separation was achieved on a Hypersil C18 column with an isocratic elution of acidified water (pH 2.5) to methanol to acetonitrile (82:12:6 per volume) at a flow rate of 1.5 mL min−1 and UV detection at 254 nm. Moreover, the proposed extraction and analysis procedures were applied to study the ability of mesoporous silica nanoparticles to remove cephalosporin residues from water by adsorption technique. A factorial design was applied to investigate the effect of pH, initial cephalosporins concentration, and adsorbent concentration on the adsorption process using removal percentage as a response. The prediction model fit well to experimental data based on statistical analysis. Adsorption kinetics and isotherm have been also studied, and the experimental results indicated that the adsorption process followed the pseudo-second-order kinetic model and Freundlich isotherm.