Removal of reactive red-P2B from aqueous solutions by montmorillonite clay; Kinetics, thermodynamic and isotherm studies

• Published in: Inorganic chemistry communications 2023-03, Vol.149, p.110386, Article 110386
• Main Author: Ebrahimzadeh-Rajaei, Gholamreza
• Format: Article
• Language: English
• Subjects: Adsorption; Isotherms; Kinetics; Montmorillonite clay; Reactive red-P2B dye; Thermodynamics
• ISSN: 1387-7003; 1879-0259
• DOI: 10.1016/j.inoche.2022.110386

[Display omitted] •The removal of reactive red-P2B by montmorillonite has been reviewed for the first time.•MMT clay were characterized by SEM, TGA, FTIR, XRD, and EDX elemental analysis.•The removal efficiency of RR-P2B as an anionic dye is significantly dependent on pH.•The maximum adsorption capacity of montmorillonite was 20.2 mg g−1 at 25 °C.•MMT can be introduced as a potential candidate for textile wastewater treatment. Adsorption of reactive red-P2B (RR-P2B) dye on montmorillonite (MMT) layer as a cost-effective inorganic clay was investigated. The prepared MMT were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), field emission scanning electron microscopy (FESEM), and X-ray energy dispersive spectroscopy (EDS). Moreover, significant factors such as pH, adsorbent dosage, initial concentration, and contact time were also evaluated extensively. It was found that the adsorption capacity of RR-P2B on MMT decreases with increasing pH and temperature. The highest dye removal capacity was obtained at pH 2, for a contact time of 60 min, and a temperature of 298 K. The Langmuir, Freundlich, and Temkin isotherm models were investigated at different concentrations, and following it, various adsorption parameters were calculated. The adsorption data were well fitted to Freundlich model and the maximum removal capacity was 20.2 mg g−1 at equilibrium time. The kinetic data followed the pseudo-second-order kinetic model, indicating that both RR-P2B and MMT influence on the adsorption process. The thermodynamic parameters such as ΔG°, ΔH° and ΔS° were calculated from the slope and intercept of the linear relation obtained from the Van’t Hoff equation. The calculated values for enthalpy and Gibb’s free energy were negative, indicating that the adsorption process is favored at low temperatures and that RR-P2B dye is physisorbed on MMT.