Adsorption of malachite green on to poplar sawdust activated carbon

ABSTRACT Dye pollution is a very important problem that needs to be prevented due to its effects on ecosystem, human and animal health. Adsorption is an economical and easy treatment method used to remove these pollutants. Today, activated carbons, which are tried to be produced from renewable resources, are widely used adsorbents thanks to its low cost and advanced surface properties. The activated carbon (AC) in this study was produced from poplar sawdust by H3PO4 activation at an acid:sawdust ratio of 4:1 and a carbonization temperature of 400°C. This AC was used to adsorption of Malachite Green (MG) from aqueous solutions. According to the experimental results, the optimum adsorption conditions were determined as 6 h at pH 5 and 25°C with 0.1 g adsorbent at 300 mg/L initial concentration and 150 mg/g adsorption capacity was achieved these conditions. Adsorption kinetics, isotherms and thermodynamics were also investigated and the results were evaluated. Surface adsorption and intraparticle diffusion are effective in the adsorption mechanism of MG on poplar sawdust AC. Since the kinetic data fit the pseudo-second-order model, it can be said that the adsorption is chemisorption. Moreover, MG adsorption was spontaneous and endothermic on a monolayer homogeneous surface.