Sustainable optimization of high specific surface area Spartina alterniflora biochar for Rhodamine B removal and mechanism

Abstract

Abstract Managing dye contaminants is a major challenge in modern water governance. This study developed a KOH-activated Spartina alterniflora biochar (KBC) adsorbent for removing Rhodamine B (RhB) dye from water. Microscopic analysis validated the presence of an appealing porous structure and surface functionalities that are key for the adsorption of RhB. KBC demonstrated an enormous specific surface area, providing many active sites (3109.67 m2·g−1). Optimal circumstances for eliminating RhB were achieved an impressive 89.77% at a pH level of 7, utilizing a KBC dosage of 100 mg/100 mL over a contact period of 48 h, resulting in a maximum adsorption capacity of 1820.47 mg·g−1. Furthermore, according to the findings, pseudo-second-order, Langmuir, and Freundlich models offered a precise match of the batch experiment results. The combined effects of the KBC pore filling, π–π electron donor–acceptor (π–π EDA), hydrogen bonding, and electrostatic interactions facilitated both physical and chemical adsorption mechanisms, which in turn bolstered the biochar’s superior adsorption capabilities. These results underscore the viability of KBC as a promising candidate for water purification, demonstrating its potential to eliminate RhB from polluted waters for sustainable cleanup efforts effectively and the resource utilization of waste.