Ionic Liquids in Air Treatment: VOCs and Other Pollutants

The global population breathes air that exceeds air quality limits which has a negative impact on human health. The degradation of indoor air quality is being attributed to several types of contaminants, like gases (carbon monoxide, carbon dioxide, ozone, nitrogen oxide and sulfur oxide species), particulate matter, but mostly to volatile organic compounds (VOCs), with different volatilities, and other emerging compounds. Despite their degree of maturity, the majority of existent technologies cannot be directly used for the removal of indoor VOCs, often due to downscale design related to feed scale and the pollutants’ partial pressures. However, new methods are being proposed, with new solvents, like ionic liquids, being proposed as materials with outstanding potential for absorption-based capture and separation processes. The distinctive characteristics of ionic liquids, such as their high thermal and chemical stability, non-flammability, non-volatility, high solubility and selectivity, and their designability make them stand out over other technologies, like metal–organic frameworks, photocatalysis, ultraviolet sterilization, ozonation, filtration, non-thermal plasma and phytoremediation. In this chapter, built on a critical literature review, the prospects of ionic liquids for target separations are assessed.