THE USE OF ADSORPTION ISOTHERMS FOR MODELLING THE NITRITE AND SULPHITE ANIONS REMOVAL FROM AQUEOUS SOLUTIONS ON A COMPOSITE MEMBRANE

Abstract

In this study was investigated the adsorption of nitrite and sulphite anions on a composite membrane. Initial anion concentration, pH and adsorbent dosage were investigated in this study, as well as the adsorption kinetics and isotherms for the composite membrane (10µm) used. Kinetics of adsorption was examined by means of three kinetic models, namely: pseudo-first-order, pseudo-second-order and intraparticle diffusion models and Langmuir, Freundlich, Temkin, Dubinin-Radushkevich isotherms. The results obtained revealed that the adsorption isotherms fitted the data in the following order: Temkin>Langmuir>Freundlich>Dubinin-Radushkevich models. The results indicated that the composite membrane exhibited potential application for removal of nitrite and sulphite from aqueous solutions. Mathematical modelling by means of adsorption isotherms shows that the interaction of sulphite and nitrite anions with membrane surface is localized in the monolayer adsorption, meaning that the adsorbed molecules are adsorbed at definite, localized sites.