Paper Title
Evaluation of Mokey Pod Tree Sawdust Modified with Urea in the Remotion of Metilene Blue: Effect of pH

Abstract
The release of effluents contaminated with dyes by industries as textile and food, has increased the concentration of synthetic colorants in the environment. If dyes are ingested in high concentrations, they can cause diverse pathologies, due of genotoxicity, mutagenesis, and carcinogenesis. From elsewhere, the timber industry produces large amounts of residues each year, which are disposed into the deposits in a direct way; those residues have great harnessing potential as feedstock for adsorbent material preparation, which can be used in the removal of pollutants dissolved in water by using the adsorption technology. Thus, the aim of the present study was synthetized and modify chemically with urea, carbon produced from mokey pod tree sawdust for its use in the removal of cationic adsorbent methylene blue (MB). For this, three carbons were prepared using different impregnation ratio of urea (1, 3 and 6 M) in a proportion of 1 g of carbon: 5 mL of urea solution. Adsorption essays were made at a MB initial concentration of 40 mg/L, 0.035 g of adsorbent and 10 mL of solution, by varying pH in 7, 8 and 9. It was obtained that, the adsorption capacity decreased inversely proportional to the pH, with a diminution of 17%, reaching the best performance using the modified carbon using the urea solution at 6 M, with a maximum adsorption capacity of 8.355 mg/g. The biochar mentioned, presented a BM index over the 25% of the reviewed studies with biochars synthetized between 180 and 400 °C, for the above it can be said that its use as alternative bioadsorbents of dyes in aqueous solution is possible. Keywords - Biochar, Chemical Modification, Colorants, Samanea saman.