Experimental study of competitive heavy metals removal from multimetal solution using wheat bran as a biomaterial: Response surface methodology

Batch and continuous adsorption studies were performed for heavy metal removal from the ternary metal system using wheat bran as an adsorbent. An adsorbent pellet was prepared using clay and chitosan as a binder. For batch adsorption experiments, the Box-Behnken design of response surface methodology was used to optimize the process parameters for adsorption. In our mixed metal continuous study, cadmium (70%-80%) and chromium (74%-80%) had shown a synergistic effect on copper removal leading to an increase in breakthrough and exhaustion time. In a continuous study, a higher breakthrough time was obtained for copper at a bed height of 0.15 cm, a flow rate of 5 mL/min and an initial metal concentration of 100 mg/L. The modeling and simulation of the continuous adsorption process were performed. The breakthrough curve obtained from the model and from experiments was compared and high R2 values up to 0.99 and low chi-square and MAPE values up to 0.018% and 0.037% indicate good fitting of model and experimental data. Regeneration studies results show that good desorption efficiency is obtained using regenerated wheat bran. The adsorbent was regenerated and reused up to five cycles and it showed good desorption efficiency of up to 95% for copper, 79% for cadmium and 80% for chromium.

Automated summary

In this study, batch and continuous adsorption experiments were conducted to investigate the removal of heavy metals from a ternary metal system using wheat bran as an adsorbent. The process parameters for adsorption were optimized using the Box-Behnken design, and the continuous adsorption process was modeled and simulated. The results showed that regenerated wheat bran exhibited good desorption efficiency and could be successfully reused for multiple cycles.