Biochar production from olive stone and investigaton of dye removal performance of biochar

This study evaluates the efficacy of biochar produced from waste biomass sources, specifically olive pits, via the pyrolysis process in removing methylene blue (MB) dye from aqueous solutions. Organic pollutants generated by the textile and dyeing industries pose a substantial threat to water resources, undermining environmental sustainability. Consequently, the development of cost-effective, eco-friendly materials with high adsorption capacities has emerged as an urgent priority. For this investigation, olive stones (OS) were chosen as the biomass precursor, and the pyrolysis procedure was conducted at 600°C for a designated time to produce biochar. The adsorption performance of the biochar was systematically assessed under various experimental conditions, including pH, contact duration, initial dye concentration, temperature, and adsorbent dosage. Optimal adsorption was achieved with a methylene blue initial concentration of 50 ppm, under acidic conditions (pH 2), at ambient temperature, and using 0.05 g of biochar. The adsorption mechanisms were scrutinized through isotherm modeling using Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich (D-R) models. Furthermore, the adsorption kinetics were investigated using multiple approaches, including pseudo-first-order, pseudo-second-order, Elovich, and intraparticle diffusion models. The findings confirmed that biochar effectively functions as an adsorbent for the removal of organic pollutants such as methylene blue. In summary, the study integrates experimental data with adsorption isotherm and kinetic analyses to derive significant insights. The results demonstrated that the Freundlich, Temkin, and Dubinin-Radushkevich isotherm models provided an excellent fit for the experimental data, while kinetic analyses indicated that methylene blue adsorption conformed to the pseudo-second-order model with high reliability. These findings underscore the potential of olive pit-derived biochar as an efficient and sustainable adsorbent for mitigating organic dye pollution in water systems.