Modification of waste potato peels by combined acid-base treatment and its adsorption performance for the removal of phenol

This study investigated the sorption capacity of potato peels for the removal of phenol from aqueous solution. The adsorption capacities of untreated potato peels (UPP) and acid-treated potato peels (APP) were compared with acid-base treated potato peels (ABPP). Characterisation of UPP, APP and ABPP by FTIR, SEM and XRD indicated that the surfaces of the adsorbents contain functional groups such as –OH, –C–O–C and –C–O. SEM images showed that the morphology of the adsorbents changed due to different chemical activations. The XRD patterns of APP and ABPP exhibited sharper peaks and higher intensities than those of UPP. The maximum sorption capacity of phenol on UPP, APP and ABPP was observed at pH 7. Adsorption isotherms showed that the Freundlich model best fitted the data, indicating multilayer sorption. The coefficient values for the PSO model were more appropriate for the uptake of phenol on all adsorbents. ABPP exhibited a higher sorption capacity for the removal of phenol, with an uptake capacity of 54.96 mg/g compared to UPP and APP.