When temperature was increased from 16 to 35 °C, the magnitude of free energy change shifted to a high negative value suggesting that the adsorption was energetically favourable, rapid and spontaneous [39]. The positive value of adsorption heat (46.32 kJ mol−1) confirmed the endothermic nature of adsorption process and the positive value of standard entropy changes suggested randomness increase at the adsorbent–solute interface during the adsorption process [14].