Simultaneous removal of hydrogen sulfide and ammonia in the gas phase: a review

The effect of the active carbonyl groups and residual acid on the ammonia adsorption over the acid-modified activated carbon

“…For the used 10M-HNO 3 -90 sample, a new shoulder peak appears at 1,273 cm −1 , which may be some kind of adsorbed NH 3 complex. It is generally recognized that hydroxyl and carboxyl groups in activated carbon provide the main active sites for NH 3 adsorption through the chemical action (Jiang et al, 2022). Although the H 2 O 2 -modified activated carbon may possesses much more hydroxyl groups (Wang et al, 2012;Liu et al, 2018), its weak NH 3 adsorption capacity implys the hydroxyl groups in activated carbon are not so acitve for NH 3 adsorption.…”

“…Ammonia (NH 3 ) is a highly toxic and extremely corrosive pollutant, which may bring undesired odors, lead to severe burning of respiratory systems, and contribute to fine particulate matter (PM2.5) concentration in the atmospheric environment (Stokstad 2014;Han et al, 2021;Jiang et al, 2022). Many different sources can release NH 3 , including home/public toilets, farm manure, liquid NH 3 refrigerants, construction waste antifreeze, expansion agents, industrial desulfurization/denitrification units (Dai et al, 2019;Zhong et al, 2019;Liang et al, 2020).…”

“…The physical adsorption of NH 3 over the unmodified-activated carbon is so weak that the NH 3 adsorption capacity even has no obvious relationship with the surface area and pore structure (Rodrigues et al, 2007). On the other hand, the oxygen-containing functional groups (especially for the hydroxyl and carboxyl groups) on the surface of modified activated carbon may provide the main active sites for NH 3 adsorption through the chemical action (Jiang et al, 2022). The activated carbon modified by acid always exhibits excellent NH 3 adsorption capacity.…”

Sensitive detection of H2S based on Ce doped ZnCo2O4 hollow microspheres at low working temperature

“…Among them, hydrogen sulde (H 2 S) is a pungent gas with a smell of rotten egg, commonly produced by industrial activities such as petroleum and natural gas extraction, wastewater treatment, coking, leather tanning, and other industrial processes. 1,2 Exposure to low concentrations of H 2 S can result in physiological issues such as eye and throat irritation, poor memory, dizziness, impaired reasoning, and loss of balance. In the event of exposure to high concentrations, it may lead to symptoms like headaches, fatigue, unconsciousness due to respiratory and cardiac damage, and even death.…”

Removal of hydrogen sulfide in the gas phase by carbide slag modified bentonite

“…[4][5][6] Dry desulfurization methods are simple, stable, and produce little secondary pollution. [7][8][9] Adsorption is the most commonly used dry desulfurization method, but during the H 2 S adsorption, the loss of adsorbent is large, which decreases the desulfurization effect and increases the cost of its removal and purication.…”