In this study, an autogenous N-doped biochar derived from Chlorella (CVAC) was prepared with NaOH as activator at 800 °C. The surface structural properties of CVAC and the adsorption performance of CVAC on tetracycline (TC) under different adsorption variables were analyzed and investigated using different characterization methods. The results showed that the specific surface area of CVAC was 491.16 m2 g-1 and the adsorption process was in accordance with Freundlich model and pseudo-second-order kinetic model. The maximum adsorption capacity of TC was 310.696 mg g-1 at pH 9 and 50 °C, and it was mainly physical adsorption. Furthermore, the cyclic adsorption-desorption behavior of CVAC using ethanol as eluent was evaluated and the feasibility of its long-term application was explored. CVAC also showed good cyclic performance. The variation of ΔG° and ΔH° confirmed that the adsorption of TC by CVAC was a spontaneous heat absorption process.
Keywords: Adsorption; Chlorella; Kinetic model; Tetracycline; Thermodynamics.
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