Authors: Inmaculada de la Calle, M. Costas-Rodríguez
Book: The Application of Green Solvents in Separation Processes, Ed. Elsevier, pp. 253-300, 2017
Microwave energy enhances and shortens the extraction of metallic and organic compounds from environmental, food, and biological samples in research laboratories, and also pilot plants and industry. Solvent-free approaches and green solvents (e.g., water, ionic liquids, supramolecular, and deep eutectic solvents) are increasingly used in combination with microwaves for the extraction of many compounds. This combination emerges as an alternative to classical extractions using organic solvents for extraction of organic compounds and mixtures of concentrated acids for the extraction of metals. Several types of microwave ovens are currently available (e.g., focused, pressurized, and dynamic). In general, these approaches are cheap, safe, fast, involving relatively low energy consumption, limited use of toxic chemicals, reduced amount of solvents and hazardous wastes, to sum up, an environment-friendly strategy. Standardized procedures, classical and new trends in microwave-assisted extraction and their combinations with other techniques are comprised. The National Environment Methods Index is also included for these methodologies.