Innovative magnetic biochar for textile wastewater treatment: a sustainable solution for methylene blue and Congo Red dye removal

The present study investigates the use of magnetic turmeric leaf biochar (MTB) as a novel, cost-effective, and eco-friendly biosorbent for the removal of methylene blue (MB) and Congo Red (CR) dyes from contaminated water. These dyes pose serious environmental risks, including water pollution and disruption of aquatic ecosystems. Adsorption experiments were conducted to evaluate the effects of various parameters such as pH, initial dye concentration, adsorbent dosage, temperature, and contact time on the decolorization efficiency of MTB. The morphological and physicochemical properties of the biosorbent were characterized using FTIR, SEM, and TGA techniques. Adsorption data were well-fitted to the Langmuir isotherm model, indicating maximum adsorption capacities of 323.625 mg g⁻¹ for MB and 256.41 mg g⁻¹ for CR. Kinetic studies revealed that the adsorption process followed a pseudo-second-order model, while thermodynamic analysis indicated a spontaneous and exothermic nature for both dyes. The adsorption mechanisms primarily involved electrostatic interactions, hydrogen bonding, and π-π bonding. Notably, MTB exhibited excellent regeneration potential, retaining 67.19% and 60.82% of its adsorption capacity for MB and CR, respectively, after six cycles. These results demonstrate that MTB is a highly promising biosorbent with great potential for sustainable and efficient wastewater treatment applications.