Abatement of gaseous volatile organic compounds: A material perspective

Volatile organic compounds (VOCs) are a class of organic liquid compounds with low vapor pressures, which enables them to vaporize at ambient conditions. VOCs are largely toxic, carcinogenic, and mutagenic, and have profound adverse effects on human health and the ecological environment. Many VOCs cause ruinous health effects even at very low concentrations (ppm) and therefore control of these organic compounds is essential for ensuring good air quality. Rising levels of VOCs in the outdoor environment, particularly in urban areas, has sparked considerable research into the abatement of VOCs. This has evolved into a myriad of pollution control technologies, including thermal catalytic oxidation, photocatalytic oxidation, non-thermal plasma, adsorption, and hybrid adsorption-oxidation processes. In order for catalytic and adsorption-based process to emerge as a promising method for VOC abatement, development of efficient materials is a crucial step. This review discusses recent developments made in the fields of catalysis and separation, with an emphasis on catalytic materials, including noble-metal catalysts, transition metal-oxide catalysts, perovskites, titania and ceria based catalysts, and dual-functioning adsorbent/catalysts. Various capture materials, such as activated carbons, zeolites, and metal organic frameworks (MOFs), are also discussed for the purpose of providing insight into the efficacy of adsorbent inclusion in hybridized separation-destruction processes.