Activated carbon production from industrial yeast residue to boost up circular bioeconomy

This work aims to obtain activated carbon (AC) from yeast residue to boost up bioeconomy. In this way, carbon was prepared from yeast biomass produced by the ethanol industry and after beta-glucan extraction. Carbon was activated with CO₂, water vapor, and a combination of both using an experimental design. The best conditions to produce AC were activation with CO₂ for 30 min at 850 °C and CO₂ flow of 0.09 L/min, set by experimental design and desirability function to optimize the yield, surface area, and microporosity. Thus, for physical activation with water vapor employing the optimized conditions, it was possible to achieve a yield of 56.6% (m/m) for AC with 1144 m²/g of surface area and mean micropore volume of 0.53 cm³/g. The maximum AC surface area reached 1616 ± 567 m²/g with a yield of 21 ± 1%. The prepared ACs were characterized by elemental analysis, X-ray diffractometry, infrared spectroscopy, thermogravimetry analysis, pH_PZC, and potentiometric titration to determine the main functional groups of sorption sites. The carbon obtained from the desirability condition was used to remove dipyrone from synthetic aqueous effluent with an experimental sorption capacity of 88 ± 4 mg/g, being the phenomenon described by the Freundlich isotherm model.