[Adsorption Characteristics of Tetracycline by CuFeO-modified Biochar].

CuFeO-modified biochars were prepared through co-precipitation and hydrothermal methods, and the composites had high efficiency removal for tetracycline (TC) from water. The CuFeO-modified biochar with a 2:1 mass ratio of CuFeO to BC450 (CuFeO/BC450=2:1) demonstrated the best adsorption performance. The kinetic process of TC adsorption by CuFeO/BC450=2:1 was well fitted with the intraparticle diffusion model, suggesting that the adsorption process was controlled by film and pore diffusion. Under the condition of neutral pH and 298 K, the maximum adsorption capacity of the Langmuir model of CuFeO/BC450=2:1 was 82.8 mg·g, which was much greater than that of BC450 (13.7 mg·g) and CuFeO(14.8 mg·g). The thermodynamic data suggested that TC sorption onto CuFeO/BC450=2:1 was a spontaneous and endothermic process. The removal of TC by CuFeO/BC450=2:1 increased first and then decreased with increasing pH, and the maximum adsorption occurred under the neutral condition. The strong adsorption of TC by CuFeO/BC450=2:1 could be attributed to better porosity, larger specific surface area, and more active sites (e.g., functional groups and charged surfaces). This work provided an efficient magnetic adsorbent for removing antibiotics.