Removal of methyl blue (MB) from aqueous solution using strontium aluminoborate (SrAl₂B₂O₇): synthesis, characterization and adsorption studies

Abstract

Today, increasing dyes pollution is of great importance for life. Leaving the dyes used in industries such as textiles without being discharged pollutes other water sources. In order to prevent this, different methods are used in the literature. In this study, SrAl₂B₂O₇, a borate metal, was used to remove methyl blue (MB), an anionic dye, by batch adsorption method. Strontium aluminoborate (SrAl₂B₂O₇) was prepared using a solution combustion method at 950 °C for 4 h in air. The prepared adsorbent was characterized by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). The particle morphology of the adsorbent was investigated using scanning electron microscope (SEM). By using N₂ adsorption–desorption, the Brunnauer, Emmet, and Teller (BET) specific surface area was found to be 1.9578 m² g⁻¹. The surface charge of the dye-adsorbed SrAl₂B₂O₇ was determined based on zeta-potential measurements. Langmuir (R²=0.9897), Freundlich (R²=0.985), Dubinin & Radushkevic (R²=0.976), Scatchard (R²=0.881), Temkin & Pyzhev (R²=0.978) isotherms were calculated in the study. SrAl₂B₂O₇ showed good adsorption performance for methyl blue (MB) with maximum adsorption capacities of 29.069 mg g⁻¹ (Langmuir). Adsorption processes were also studied in detail. Thermodynamic and kinetic models; pseudo-first-order (R²=0.415), pseudo-second-order (R²=0.999), Elovich (R²=0.968) showed that adsorption using SrAl₂B₂O₇ in MB removal is endothermic and pseudo-second order.

GRAPHICAL ABSTRACT

Keywords:

• Adsorption
• methyl blue
• SrAl₂B₂O₇
• langmuir
• freundlich