This work aims to study caffeine removal from an aqueous solution through adsorption on laponite. Experimental analysis of adsorption in batch scale was performed to verify the influence of pH (2 to 10), the concentration of solid adsorbent (0.5 to 5.0 g L⁻¹), and the contact time (1 to 150 min). The adsorption equilibrium was analyzed using Bayesian Information Criteria metric statistics to define the isotherm model of caffeine removal. The Bayesian Markov Chain Monte Carlo technique estimated the main isotherm parameters. The thermodynamics tests were performed at three different temperatures (303, 313, and 323 K) using concentrations from 10 to 4000 g L⁻¹. The results showed that the kinetics study at pH 4 and 5 g L⁻¹ of laponite was efficient, exceeding 90% of caffeine removal even in a short period of adsorption time (after 1 min). The equilibrium state was reached at about 20 min of contact time. Redlich-Peterson and Sips were the isotherm models that best fit the experimental data. The thermodynamics study suggested that the caffeine adsorption on laponite was spontaneous, exothermic, and mainly was governed by physisorption. The results showed that adsorption is a suitable method for removing emerging pollutants like caffeine. Furthermore, laponite is a promising material to remove them.

• Laponite is mesoporous and there was no change in structure after adsorption

• Parameters from the isotherms studied shows smooth dependence of the temperature

• The Sips and Redlich-Peterson isotherm models best described the experimental data