Membranes for air cleaning

Nowadays, one of the most relevant issues that the world is facing deals with the pollution of natural sources including water and air (Ursino et al., 2018). Air pollution implies the presence of various chemical agents, volatile organic compounds (VOCs), particulate matter (PM), among others, that decrease the air quality, affecting several environmental cycles and contributing to climate change (Van Tran et al., 2020). Furthermore, polluted air can directly harm the health of humans, animals, and plants (Manisalidis et al., 2020). In humans, such polluting compounds can be transported through the respiratory system by means of inhalation, provoking respiratory and cardiovascular diseases, reproductive and central nervous system dysfunctions, and severe forms of cancer (Kelishadi and Poursafa, 2010, Mannucci et al., 2017). The main contaminants related to such chronic diseases are CO and CO2, SO2, nitrogen oxides (NO and NO2), VOCs, suspended PM (soot, dust, asbestos, lead, etc.), photochemical oxidants (ozone O3), and radioactive substances (Amano, 2010, Castro-Muñoz et al., 2019, Miller, 2017). In developed countries, the air quality has deteriorated rapidly in recent decades as consequence of a complex interaction between natural and anthropogenic environmental conditions (Mayer, 1999). Inherently, air pollution in developed cities represents a serious environmental issue. The air pollution of the urban atmosphere relies on the emission and transmission of air pollutants. For instance, Fig. 8.1 illustrates the main sources of contaminants and polluting compounds of the air in an urbanized area. Since most of these human primary activities cannot be banned, there is a strong need of attending to such a worldwide issue with the proposal of suitable treatment techniques for removing such pollutants from the air (Rashidi et al., 2012). To date, several separation techniques have been proposed including absorption, adsorption, incineration (or combustion), and their possible coupling. Such processes are mainly used for the removal of gaseous pollutants, along with VOCs and other fine chemicals.