Adsorption of phosphate ions onto low cost Aleppo pine adsorbent

In the present study, chemically modified Aleppo pine sawdust was used for the removal of phosphate from water. Sorption of phosphate ions onto biosorbent was studied using the batch technique. The effect of different parameters such as contact time, adsorbate concentration, and temperature was investigated. The adsorption kinetics data were best described by the pseudo-second-order rate equation, and equilibrium was achieved after 40 min. The Langmuir and Freundlich equations for describing adsorption equilibrium were applied to data. The constants and correlation coefficients of these isotherm models were calculated and compared. The adsorption isotherms obey the Freundlich equation. The thermodynamic parameters like free energy, enthalpy, and entropy changes for the adsorption of phosphate ions have been evaluated, and it has been found that the reaction was spontaneous and endothermic in nature. The low value of activated energy of adsorption, 3.088 KJ mol−1, indicates that the phosphate ions are easily adsorbed on the sawdust. Results suggest that the prepared chemically modified Aleppo pine sawdust has potential in remediation of contaminated waters by phosphate.

Research Highlights
► Chemically modified Aleppo pine sawdust adsorbs well phosphate ions.
► The adsorption of phosphate ions on chemically modified Aleppo pine sawdust was fast.
► The adsorption process was spontaneous, endothermic and controlled by chemisorptions.
► Sawdust chemically treated is low-cost adsorbent for phosphate ions.