Antibiotic removal by activated biochar: performance, isotherm, and kinetic studies
Biomass waste (Chinese traditional medicine residues) is one of the most promising sources of biochar. Here, the present study illustrated the activated biochar (BCA) was prepared using the herb residue (Astragalus membranaceus) via sodium carbonate (Na2CO3) activation for the removal of Cefradine (CF) in wastewater. The adsorbents were characterized by scanning electron microscopy, N2 adsorption-desorption analysis, Fourier transform infrared spectrum, X-ray diffraction, X-ray photoelectron spectroscopy and zeta potential analysis. The effects of initial pH value, BCA dosage, initial CF concentration and coexisting ion for CF removal were investigated. BCA showed much higher absorption capacity for CF (qm=64.76 mg/g) than the pristine biochar (BC). The uptake capacity of BCA and BC for CF was found to be pH-dependent. The analysis of the kinetic and isotherm studies indicated that strong chemical-sorption interactions occurred on the surface of BCA. The removal mechanisms of CF onto BCA would include π-π EDA interaction, hydrogen bonding, ion exchange and electrostatic adsorption. In addition, the fixed bed experiments demonstrated that BCA could be a promising and highly effective adsorbent to treat large volume of CF-contaminated wastewater.