Removal of some organic compounds from pre-treated olive mill wastewater by sepiolite

Abstract

In this study, Olive Mill Wastewater (OMW) was treated with lime to a pH.7.0, followed by 30% H2O2 solution. Phenol. lignin and colour changes were analyzed by UV- VIS spectrophotometry after a one-week period. Phenol and lianin removals were found to be 99.5 % and 35 %, respectively. Then, adsorption experiments were conducted on these solutions by using different sepiolite samples, i.e. heat-activated sepiolite (AS), thermal-acid-activated sepiolites (AAS), and thermal-base-activated sepiolites (BAS). The surface modification of these samples was examined by the SEM, XRD and FT-IR techniques. Phenol and lignin removal was investigated at different adsorption times by these sepiolite samples. BAS samples were shown to provide more removal than those of AAS and AS. In addition, the kinetic data supported the pseudo-second order model, but showed very poor fit for pseudo-first order and intraparticle diffusion models. The adsorption data for AS were also fitted to Lanomuir and Freundlich isotherms. AS exhibited a better fit to Langmuir than Freundlich. Finally, Gibbs-free energy for lignin and phenol were calculated.