Application of Olive Stone Based Activated Carbon in the Sorption of Lanthanum (III) Ions from Aqueous Solution

A biomass agricultural waste material, olive stone (OS) was used for preparation of activated carbon (AC) by chemical activation using 50% phosphoric acid (PA5) carbonized at 800C and holding time 90 min (OSPA58).The prepared AC was used for sorption of La(III) ions from nitrate solution.The effect of various factors such as shaking time, pH, carbon dose, particle size and different temperature on the adsorption capacity of Lanthanum onto activated carbon were quantitatively determined.The two equilibrium models; Langmuir and Freundlich, were discussed and the data were fit with Langmuir modelwith a monolayer capacity of 201.6 mg/g. The kinetics of sorption was described by a pseudo second-order rate model. Thermodynamic calculations pointed towards the feasibility of an adsorption process with spontaneous and endothermic nature with a value of ∆G= -19.3 KJ/mol, ∆H=10.98KJ/mol and ∆S=12.89x10KJ/mol.