Removal of anionic and cationic dye from aqueous solutions with modified biochar <i>Gypsophila arrostii var nebulosa</i> : characterization, isotherm, kinetics, thermodynamics studies

Anionic and cationic dyes are two basic types of dyestuffs classified based on their chemical structure and electrical charge. These dyes are used to give color in industrial and application areas such as textiles, paper, food, and ink. The untreated discharge of these dyestuffs into clean water sources poses a significant danger to living organisms. In this study, <i>Gypsophila arrostii var nebulosa</i> (GA) was used to prepare biochar (b-GA), which was then modified (mb-GA). Then, the adsorption properties on methyl blue (MeB), an anionic dye, and methylene blue (MB), a cationic dye, were investigated. Characterization of the biochar showed it to be amorphous. When the adsorption processes were analyzed, it was determined that the process was pseudo-second-order, endothermic, and fit the Langmuir isotherm model. The maximum adsorption capacity (q_max) was found to be 17.065 mg/g for b-GA-MeB, 44.444 mg/g for mb-GA-MeB, 28.011 mg/g for b-GA-MB, and 49.505 mg/g for mb-GA-MB.