Biochars for the removal of toxic gaseous contaminants: state-of-the-art and future directions

Abstract

Toxic gaseous contaminants comprised of various harmful gases emitted into the atmosphere have emerged as a key environmental and public health concern. Gaseous contaminants can broadly be categorized into inorganic and organic contaminants. The inorganic contaminants include nitrogen oxides (NOx), sulfur dioxide (SO2), toxic heavy metals (Pb, Cr, Hg), carbon monoxide (CO), carbon dioxide (CO2), and ammonia emissions. Organic contaminants, on the other hand, include volatile organic compounds (VOCs), poly organic pollutants (POPs), polycyclic aromatic hydrocarbons (PAHs), odorous compounds, dioxins, and furans. Thus, polluted air contains an unacceptable concentration of the above-mentioned contaminants.