Removal of Azo Dye Methyl Orange in Aqueous Solution by Kaolinite Clay: Equilibrium Isotherms, Kinetics and Error Analyses

Abstract

Decolourisation of wastewater, particularly from textile industries is one of the major environmental concerns these days. The limitations of most of these treatment methods are their high operational and maintenance costs cannot effectively be used to treat wide range of such wastewater. This work describes the use of kaolinite clay as an efficient adsorbent material for anionic azo dye methyl orange removal from synthesized wastewater. Batch adsorption experiment of 200 mgL -1 azo dye methyl orange contaminant removal using kaolinite clay at different stirring speed: 100, 200, 300, 400 and 500 rpm at constant pH4 and contact time of (0 ‒ 180) minutes were investigated, thus, adsorption increases with increase in stirring speed with maximum removal of 69.90% and maximum adsorptive capacity of 3.476 mg/g at 500 rpm. The adsorption equilibrium data were well described by Langmuir>Freundlich>Koble-Corrigan whilst adsorption kinetic data by pseudo second-order>pseudo first-order>intraparticle diffusion>Reichenberg equation in the stated order based on high correlation coefficients and relatively small values of error function analyses (χ 2 , RMSE, NSD and ARE). The adsorption processes were controlled by chemisorption. The potential applicability of Alkaleri kaolinite clay from Northeast-Nigeria could be employed as a low-cost adsorbent alternative to commercial/activated carbon in the removal of azo dye methyl orange from wastewater.