Palm leaf ash as a biosorbent for improving the efficiency of the silver removal process

Water pollution caused by heavy metals due to the increasing growth of industries is very worrying. Among heavy metals, evaluating the effect of silver (Ag) toxicity and its challenges on human and environmental health is very important and fundamental. This paper, for the first time, assessed the ability of palm leaf ash (PLA) as a biosorbent to reduce the amount of water-soluble Ag cations from water. To do so, the effect of adsorbent amount, contact time, initial concentration of Ag ions, pH of the solution, and the temperature was evaluated on the adsorption process. The adsorption process was more consistent with the Freundlich isothermal model and the pseudo-second-order model was in better agreement with experimental data. The results of the experiments showed that the removal percentage of Ag ions and adsorption capacity was accrued from 91.84 to 99.94% and from 25.89 to 52.771 mg/g with increasing pH from 3 to 8 respectively and the enthalpy of the adsorption process (ΔH) was 6996.36 j/mol. Furthermore the removal efficiency of Ag at the initial concentration was obtained at 99.7%, Therefore, it can be concluded that cheapness, and abundance and high sorption capacity are the main advantages of this adsorbent.