Adsorption of resorcinol onto synthetic calcium phosphate compounds: Kinetic, isotherm, and thermodynamic studies

Using batch adsorption methods, this work examines the adsorption behavior of resorcinol onto two artificial calcium phosphate compounds, tricalcium phosphate apatite (PTCa) and octocalcium phosphate apatite (OCPa).The study is to assess these materials' adsorption capacities and investigate the impacts of important parameters like pH, temperature, starting concentration, and adsorbent dosage.When both the Freundlich and Langmuir isotherm models were used, the Langmuir model fit the data better, suggesting monolayer adsorption.PTCa and OCPa were shown to have maximal adsorption capabilities of 13.27 mg/g and 5.05 mg/g, respectively.According to kinetic studies, the adsorption process exhibits pseudo-second-order kinetics, which points to chemisorption.The adsorption is exothermic and spontaneous, driven by physical interactions including van der Waals forces and hydrogen bonds, according to thermodynamic considerations.The study comes to the conclusion that PTCa and OCPa, with their high adsorption capacities and advantageous thermodynamic and kinetic properties, are attractive materials for the elimination of resorcinol from aqueous solutions.