Effective removal of methylene blue and crystal violet by low-cost biomass derived from eucalyptus: Characterization, experiments, and mechanism investigation

Herein, a novel succinic anhydride modified eucalyptus wood biomass adsorbent (SAEPB) was synthesized. The removal of crystal violet (CV) and methylene blue (MB) dyes was investigated by this adsorbent. Systematic experiments were conducted to assess various factors affecting dye removal efficiency, including adsorbent dose, pH and contact time. The results showed that SAEPB achieved impressive removal rates of 99.86% for CV and 99.79% for MB at an adsorbent dosage of 0.03 g, an initial solution concentration of 100 mg L-1, a pH of 9, and a contact time of 12 h. Multiple adsorption isotherms were employed, with the Langmuir model providing the best fit to the experimental data. The maximum adsorption capacity of the adsorbent was found to be 469.494 mg g-1 for CV and 380.398 mg g-1 for MB at 298.15 K, respectively. The pseudo-second order accurately describes the adsorption rate process in the kinetic model developed. Furthermore, thermodynamic parameters indicated that SAEPB/CV interface exhibits an endothermic, spontaneous adsorption process with increased randomness, while the SAEPB/MB interface showed exothermic, spontaneous adsorption with enhanced system order. This low-cost biomass adsorbent derived from eucalyptus wood modification exhibits significant potential, offering a cost-effective, and promising solution for various applications.