Adsorption efficiency of groundnut husk biochar in reduction of rhodamine B, recycle, and reutilization

Industrial development has significantly increased the off dyestuff in the environment, resulting to serious environmental contamination in recent years. The high concentration of dye in aquatic environments has spurred researchers to focus on remediation strategies for the removal of dye from wastewater. Thus, adsorption has emerged as an effective and economically viable method for removing dye. Biochar is used due to its diverse raw material sources, cost-effectiveness, and recyclability, stands out as a valuable resource in environmental remediation. This study uses comprehensively characterized the groundnut husk biochar (GHB) by using FTIR, BET surface area analysis, and pHpzc determination techniques. Considering Freundlich isotherm fitting, the maximum adsorption capacities of GHB for RhB are 182.24 mg g⁻¹ and removal efficiency of 94.0% at the pH of 3, with 0.30 g L⁻¹ adsorbent dosage, surpassing those noted for other biochar’s in the literature. In the thermodynamic study of adsorption, ΔG was determined to be negative, indicating to feasible and spontaneous adsorption process. The findings from this are all one study; the main mechanisms involved in RhB removal via GHB, including ion exchange, filling of pores, π-π interactions, electrostatic attraction, and bonding of hydrogen, were presented. The research study indicates that GHB is reusable, with significant adsorption capacity even after third consecutive cycles of regeneration leading to environmentally, and cost-effective absorbent, even at temperatures ambient or below. Further study is needed to investigate other regeneration techniques for biochar to prolong its usefulness to dye absorption, hence decreasing the costs involved in disposing of the by-products.