Preparation and application of distiller’s grains-based carbon materials

Abstract

Distiller’s grains are the main solid biomass waste from the ethanol industry and the brewing process, featuring a wide range of sources, high carbon content, and a rich variety of elements. Owing to rich cellulose, lignin, crude protein and starch after fermentation and distillation, the distiller’s grains are the ideal precursors for biomass carbon materials. Distiller’s grains-based carbon materials are prepared by high-temperature pyrolysis or hydrothermal treatment as well as physical or chemical activation, using distiller’s grains as the carbon source. Because of their high carbon content, large specific surface area, pore structure and rich variety of elements, the distiller’s grains-based carbon materials have been widely concerned and studied. Herein, the current research status of the distiller’s grains-based carbon materials is reviewed in terms of raw material composition, preparation methods and applications fields. For the distiller’s grains produced by different regions and brewing methods, the main differences lay in the ratio of components such as cellulose, lignin and crude protein, and in the content of elements such as N, S and P. Typical preparation methods of the distiller’s grains-based carbon materials are summarized and compared, including pyrolysis, hydrothermal method and activation method. Also, the development tendency of preparation method is pointed out. In addition, the progress of current applications of the distiller’s grains-based carbon materials in energy (supercapacitors, batteries), environment (heavy metal ion adsorption, sewage purification), agriculture (soil improvement, slow-release fertilizer carrier) and catalytic fields (oxygen reduction, organic pollutant degradation) are introduced. Finally, the problems in the preparation and application of the distiller’s grains-based carbon materials are proposed, and their future development and application are prospected.

Keywords

• distiller’s grains
• carbon materials
• biomass
• composition
• preparation
• application