Kinetics and thermodynamics of textile dye removal by adsorption onto iron oxide nanoparticles

Abstract

Contamination of potable water supplies will in the future lead to the emergence of problems like lack of water. Therefore, the issues such as environmental pollution and the purification of water have been a major focus of scientists recently. Especially, the removal of the heavy metals and organic substances that are harmful to human health and exist in industrial waste water is of great importance. In this study, removal of textile dye (Maxilon® Blue GRL 300%, MBG), which is a significant impurity, from water was carried out by using iron oxide nanoparticles. Iron oxide nanoparticles were synthesized by using co-precipitation method. XRD, SEM, TEM, size distribution, zeta potential and magnetic properties measurements were performed to investigate the properties of the nanoparticles. The MBG removal capacities of iron oxide nanoparticles were investigated by taking into account the initial metal ion concentration, pH of aqueous medium, time and temperature. The dye adsorption capacity of iron oxide nanoparticles increased with an increase in dye concentration and temperature. The highest dye removal was observed at pH 9.0. According to the evaluation of the dye concentration effect on adsorption process, when the highest concentration of 25.0 mg/L dye solution was used at room temperature, the highest dye adsorption capacity was determined as 0.23 mg/g. The results of adsorption kinetics and thermodynamic data have shown that adsorption process has pseudo-second-order kinetics and endothermic form. Adsorption studies data have well fitted to Langmuir isotherm at room temperature.