In-situ copper-based metal–organic framework tailored clay synthesis for efficient pharmaceutical removal: Comprehensive adsorption and optimization studies

The present study focuses on solvothermal in-situ synthesis of copper-based metal-organic framework (Cu-MOF) supported montmorillonite (MMT) composites (CuMMT) with various Cu-MOF mass ratios (5%, 10%, and 20%) and examine these composites as adsorbents for adsorption of tetracycline (TC) antibiotic. CuMMT composites were characterized by performing FTIR, XRD, BET/N₂, SEM, and zeta potential analyses. The impacts of temperature, initial antibiotic concentration, contact time, and solution pH on adsorption were investigated deeply. The pseudo-second-order and Elovich kinetic models were consistent with the obtained kinetic results which proposed chemical interactions. According to the studies, the monolayer Langmuir isotherm model fits the adsorption systems rather well. TC adsorption constituted a spontaneous endothermic reaction. As a result of the adsorption experiments, 10CuMMT composite showed the highest adsorption capacity as 319.57 mg g^-1 at a contact time of 240 min, pH 7.32 (natural pH of TC solution), at a temperature of 318 K. To enhance the TC adsorption process, the Box-Behnken experimental design was used. The optimized conditions (contact time = 200 min; solid/liquid ratio = 0.08 g L^-1; temperature = 318 K) enhanced TC adsorption capacity to 330.70 mg g^-1.