Enhancing Dye Removal Efficiency Through Sustainable Adsorbent Production from Corncobs (Zea mays L. ssp. amilacea)

Active surface materials such as activated carbon are used in the removal of contaminants and dyes in effluents. The primary objective of this study was to convert starchy corncobs into valuable activated carbon, capable of efficiently adsorbing dyes, and to comprehensively analyze the resulting material’s physical and structural properties. To achieve this purpose, a 23 factorial design was employed to create optimized activated carbon for effective methylene blue dye adsorption. The factors considered were carbonization temperatures, carbonization times, and H3PO4 activating agent concentrations. This design yielded eight types of activated carbon, namely B-85%, D-85%, M-85%, L-85%, A-45%, S-45%, P-45% and X-45%, observing that the increase in temperature and carbonization time had negative effects on the adsorption capacity, while the increase in the percentage of activating agent had positive effects. The variant labeled as A-45% displayed the highest cationic methylene blue dye removal efficiency, boasting a remarkable adsorption capacity of 99.93%. This result almost reached the performance of commercial activated carbon, which exhibited a similar methylene blue dye removal efficiency (99.94%), while the removal efficiency of the anionic dye nigrosin was 95.24%. X-ray diffraction analysis of activated carbon A-45% indicated a slightly crystalline amorphous structure. Moreover, surface area analysis utilizing the BET method revealed that this material possessed a micromesoporous nature, mainly consisting of cylindrical micropores, resulting in an impressive surface area of 306,493 m2/g. FTIR analysis revealed the presence of functional groups, including O-H, C=C, C-O, C-X, and P=O, which create a highly polar surface that enhances the chemisorption of cationic molecules like methylene blue. These findings demonstrate the potential application of the synthesized activated carbon in industrial effluent treatment processes.