A study of olive mill waste water removal by a biosorbent prepared by olive stones

Abstract

In this work, olive mill wastewater (OMW) such as dyes is very toxic even present as traces in industrial wastewater effluents. It may constitute a potential pollution source of ground waters and hence it has to be eliminated. Various low cost adsorbents have been studied for their applicability in treatment of different types of effluents. In this study, the potential of activated carbon derived from Olive Stones was studied for the removal of OMW. The biosorption of OMW from aqueous solutions by Olive Stones (OLS) as a low-cost, natural and eco-friendly biosorbent was investigated and by KOH and H3PO4 treated Olive Stones (AOLS). Biosorption kinetic data were properly fitted with the pseudo-second-order kinetic model. The experimental isotherm data were analyzed using Langmuir, Freundlich isotherm equations. The best fit was obtained by the Langmuir model with a Langmuir maximum monolayer biosorption capacity of 189,83 mg/g for OMW. The biosorption was exothermic in nature (ΔH° = -105,54 kJ/mol). The reaction was accompanied by a decrease in entropy. The Gibbs energy (ΔG°) increased when the temperature was increased from 303 to 320 °K indicating a decrease in feasibility of biosorption at higher temperatures. The results have established good potentiality for the Olive Stones to be used as a sorbent for the removal of olive mill wastewater.