A novel-green adsorbent based on Sanxan microsphere for removal of methylene blue

This study aimed to prepare a novel biosorbent from Sanxan and evaluate its efficacy for methylene blue (MB) removal from aqueous solutions. The structure and morphology of the prepared Sanxan microspheres (SXM) were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The influence of key parameters, including initial MB concentration(100-600 mg/L), pH (2-12), contact time (0.5-48 h) and temperature (15-45 °C), on adsorption performance was evaluated. The results showed that SXM exhibited a high MB adsorption capacity (219.68 mg/g) over a wide temperature range of 20-35 °C and a maximum removal efficiency of 96.02 % at pH 11. The exposure of adsorbent surface sites is favored under alkaline conditions, and the deprotonated carboxylic acid groups on the surface of SXM bind to the MB cations via electrostatic attraction as the dominant mechanism of adsorption. These results revealed that SXM is a highly effective adsorbent for MB removal. The study provides valuable insights into the adsorption mechanism and supports the potential application of Sanxan in dye wastewater treatment.