Facile synthesis of silicon carbide/hydroxyapatite composites through ball-mill for enhancing adsorption of tetracycline

Tetracycline adsorption from aqueous solution was investigated using silicon carbide/hydroxyapatite (SiC/HA), which is a novel adsorbent used for the first time in this study. Batch adsorption experiments were conducted to identify the effects of adsorbent amount, contact time, solution pH and temperature. The maximum adsorption capacity was found to be 5.88 mg g−1 for 60/40 ratio, while raw SiC and HA samples exhibited lower capacities for tetracycline adsorption (2.11 mg g−1 and 3.50 mg g−1). Maximum adsorption capacity was obtained at pH 7 with qe = 2,16 mg g−1. Langmuir and Freundlich isotherm models were used to analyse experimental data and the results showed that monolayer tetracycline adsorption occurred on SiC/HA surface, which leaded Langmuir isotherm model with maximum adsorption capacity of 45.87 mg g−1. Kinetic studies were performed at different time intervals and experimental data were analysed by pseudo-first order and pseudo-second order kinetic model. The pseudo second-order kinetic model defined the experimental data better than the others (R2 = 0.99). Moreover, thermodynamic studies revealed that TC adsorption was an endothermic process with spontaneous nature and feasible.