Modified biochar supported Ag/Fe nanoparticles used for removal of cephalexin in solution: Characterization, kinetics and mechanisms

• Published in: Colloids and surfaces. A, Physicochemical and engineering aspects Physicochemical and engineering aspects, 2017-03, Vol.517, p.63-71
• Main Authors: Wu, Hongwei, Feng, Qiyan, Yang, Hong, Alam, Easar, Gao, Bo, Gu, Deming
• Format: Article
• Language: English
• Subjects: Biochar; Cephalexin; Degradation products; Nanoparticles
• ISSN: 0927-7757; 1873-4359
• DOI: 10.1016/j.colsurfa.2017.01.005

[Display omitted] •Modified biochar supported Ag/Fe nanoparticles (Ag/Fe/MB) were successfully synthesized.•Ag/Fe nanoparticles exhibited better dispersion on the surface of modified biochar.•Cephalexin removal on Ag/Fe/MB occurred by simultaneous adsorption and reduction.•The degradation pathway of cephalexin was analyzed. The environmental risks caused by residual antibiotics have attracted great attention. In this study, a new method was performed using modified biochar supported Ag/Fe nanoparticles (Ag/Fe/MB) to remove cephalexin (CLX) in aqueous solution. More than 86% of CLX was removed by Ag/Fe/MB in 90min under the simultaneous action of adsorption and reduction (dose: 1.5g/L, CLX initial concentration: 20mg/L, pH: 6.15). Notably, the adsorption was more prevalent than the reduction during the removal of CLX. The results of scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) of Ag/Fe/MB confirmed the presence of Ag/Fe nanoparticles and a good distribution on the surface of support matrix. Removal of CLX was seriously dependent on adsorbate concentration and pH. The presence of citric acid (CA) strongly increased the removal of CLX, where the initial reaction rate was increased by 36.03 times. Degradation products of CLX, generated by removing functional groups from the structure of CLX, were analyzed by liquid chromatography–mass spectrometry (LC–MS) to investigate the degradation pathway.