Synthesize of montmorillonite supported hydroxyapatite and determination of adsorption capacity by tetracycline removal

In this study, removal of organic pollutants in wastewater using HA/MMT composite material was studied. Tetracycline (TC) antibiotic was used as an organic pollutant. HA/MMT composites were synthesized in a ball mill at different ratios (1:1, 1:2 and 2:1). The synthesis time was fixed at 5 hours. As a result of the experiments, it was concluded that 1:2 ratio of HA/MMT composite has the highest adsorption capacity (147 mg g-1) among the others. The isotherm experiments showed that the Langmuir isotherm model was compatible with the experimental data, and the maximum adsorption capacity was obtained as 150 mg g-1. In the light of kinetic data, pseudo-first-order, pseudo-second-order kinetic models and intra-particle diffusion models were examined and it was found that the pseudo-second-order kinetic model was the best suitable model for TC adsorption. In addition, it has been observed that intra-particle diffusion takes place as a rate-determining step. It has been concluded that TC adsorption of HA/MMT composite was an endothermic and spontaneous process thermodynamically. It has been concluded that the synthesized HA/MMT composite has high adsorption capacity and can be used for the removal of organic pollutants such as TC from wastewater.