Olive mill wastewater phenolic compounds adsorption onto active olive stones: equilibrium isotherms and kinetics study

Abstract

Phenol, being the major wastewater pollutant has adverse effects on the human health. Various biological and non-biological methods are used for removal of the phenol from wastewater such as adsorption, photodecomposition, volatilisation and others. The present study is focused on studying the environmental state of art of olive mills operating in the southern areas of Tunisia. It also investigates the feasibility of transforming olives solid residue into an effective, high capacity and low cost adsorbent for total phenol removal from olive mill wastewater (OMWW). Results indicated that the used activated olive stones, with 368.3 m2/g BET surface area, exhibit high total phenol adsorption capacity. Adsorption equilibrium is represented by Langmuir isotherm model (Q0 = 333.3 mg/g). Total phenol adsorption kinetics is best modelled by pseudo-second order reaction rate and Dumwald-Wagner (intra-particle) diffusion model. Reduction of the total phenol content in OMWW is achieved in mini column test of activated olive stones fixed bed adsorption.