Various kinetic models were applied to study the adsorption of phenolic compounds. The commonly used models are first-order, pseudo-first-order and pseudo-second-order. Among these, the pseudo-first-order kinetic model (Lagergren model) was used [29]. The expression of the model is as follows, where kad is the adsorption rate constant, and qe and qt are the adsorbed concentrations of TCP at equilibrium and at a time t. By plotting a graph of log(qe qt) versus time for different concentrations and temperatures, straight lines were obtained (Fig. 4), indicating the agreement with a first-order expression. The rate constants are given in Table 1. The kad parameter is the timescaling factor, the value of which decides how fast the equilibrium in the system can be reached. The dependence of the kad constant value on the applied initial solute concentration varies from one system to another. It usually decreases with the increasing initial solute concentration in the bulk phase. In this present study, the kad values were found to decrease with increase in concentration. This change in kad value with initial concentration indicates the sorption is dependent on pH and temperature [30]. A decrease in kad values with an increase in temperature indicates the exothermic nature of the adsorption.