Waste Biomass Utilization for the Production of Adsorbent and Value-Added Products for Investigation of the Resultant Adsorption and Methanol Electro-Oxidation

Waste valorization is necessary in today’s society to achieve a sustainable economy and prosperity. In this work, a novel approach to the waste valorization of cuttlebone was investigated. This material was ground and calcined at 900 °C for 5 h in an inert atmosphere. The resulting calcined cuttlebone (CCB) was characterized using XRD, SEM, FTIR, BET, TGA, Zetasizer, and potential methods. The main phases in the CCB were determined to be CaO, MgO, Ca3(PO4)2, and residual carbon. CCB was investigated as an adsorbent for the removal of dye from simulated wastewater streams. The maximum adsorption capacities for rhodamine B and crystal violet dyes were estimated to be 519 and 921 mg/g, respectively. For both dyes, the Avrami model was the best-fit model for representing adsorption kinetics. The study of adsorbent regeneration for CV as a representative example involved the use of several chemical solvents. Ethanol solvent was shown to have the highest adsorbent regeneration method efficiency, reaching 65.20%. In addition, CCB was investigated for methanol electro-oxidation for energy generation. As the methanol concentration increased, the maximum current density produced by the CCB increased, reaching approximately 50 mA/cm2. This work paves the way toward waste valorization of natural matter for sustainable production and consumption of material, as per the requirements of the circular economy principles.