عنوان مقاله [English]
In this study, the ability of cationic dyes removal from textile effluent in both singular and binary systems has been investigated by using Feldspar. Two cationic dyes, Basic Blue 41 and basic Red 18, were used as cationic dye models. The surface characteristics of Feldspar were studied using Fourier transform infra-red, Scanning electron microscope, and X-ray diffraction (XRD) techniques. Moreover, the influence of different process variables such as adsorbent dosage, dye concentration, initial pH, and the presence of different electrolytes were investigated. The adsorption isotherms of single and binary systems were determined. The mono-component Langmuir isotherm model was applied to analyze the experimental data of single system and the isotherm constants were calculated for these two dyes. The monolayer coverage capacities of feldspar for Basic Blue 41 and Basic Red 18 dyes in the single system were found as 5.714 and 4.650 mg/g, respectively. Also, the equilibrium adsorption of binary system was analyzed using the extended Langmuir models. The adsorption kinetics of single and binary systems were studied by using pseudo-first-order and pseudo-second-order models. The pseudo-second-order model was the best choice between the kinetic models to describe the adsorption behaviour of both single and binary systems. According to the dependency of thermodynamic equilibrium constant (Ks) on temperatures, the thermodynamic parameters associated with the adsorption process were calculated. The negative values of ΔG0 indicate that the adsorption process is spontaneous and the adsorption mechanism is physical adsorption. The positive values of ΔH0 show that the adsorption processes are endothermic.