Highly efficient removal of methylene blue by a synthesized TiO2/montmorillonite-albumin nanocomposite: kinetic and isothermal analysis in water

Abstract

Color removal from industrial effluents, especially in the textile and dyeing industries, is of great interest nowadays. In this research an experimental study was performed to investigate the efficiency of a TiO₂/montmorillonite-albumin nanocomposite (TMAN), synthesized by a green process for the first time, in the removal of methylene blue (MB) from solutions. The as-synthesized TMAN was characterized using transmission electron microscopy (TEM), Fourier transformed infrared spectroscopy (FT-IR) and powder X-ray diffraction (XRD). The results of the evaluations showed that the particle size of TMAN is about 21.79 ± 8.671 nm. The effect of different parameters such as initial concentration of MB, contact time, adsorbent dosage and pH were determined. The results showed that increasing the concentration of MB, adsorbent dosage, temperature and pH increases the removal efficiency of MB. The optimum for this process was reached at 3 h and the optimum pH for adsorption of MB with by TMAN was in the range of 7–11. The equilibrium data were also fitted to the Temkin, Langmuir and Freundlich equilibrium isotherm models. The results showed that the data fitted to Langmuir (R² = 0.965) better compared with Freundlich (R² = 0.936) and Temkin (R² = 0.774) models. Maximum adsorption capacity was 18.18 mg g⁻¹. Since industrial wastewaters have alkaline pH, TMAN can be used for the removal of dyes from industrial wastewaters and aqueous solutions.