Wood Vinegars: Production Processes, Properties, and Valorization

Abstract

Pyrolysis of lignocellulosic biomass is widely used for the production of charcoal, pyroligneous liquid, and noncondensable gases. All three are value-added products that are exploited in several fields. However, this review focuses on three main areas: wood vinegar production methods, its physicochemical properties, and the use of wood vinegar or pyroligneous acid in agriculture and the environment. Wood vinegar is a liquid derived from wood by the condensation of gases and vapors released during the carbonization process, which is the transformation of wood into charcoal. It is mainly composed of aliphatic, aromatic, and naphthenic hydrocarbons and other oxygenated compounds such as alcohols, aldehydes, ketones, furans, acids, phenols, and ethers. Wood vinegar has antioxidant and free-radical-scavenging properties and is used in agriculture as an antimicrobial, antifungal, insecticide, and plant germination and growth agent. It is also used in food preservation, in medicine, and in the ecological preservation of wood. This review also examines the state of the art in pyroligneous liquid production techniques and factors that could potentially affect its quality.