Review on Catalytic Oxidation of VOCs at Ambient Temperature

Abstract

As an important air pollutant, volatile organic compounds (VOCs) pose a serious threat to the ecological environment and human health. To achieve energy saving, carbon reduction, and safe and efficient degradation of VOCs, ambient temperature catalytic oxidation has become a hot topic for researchers. Firstly, this review systematically summarizes recent progress on the catalytic oxidation of VOCs with different types. Secondly, based on nanoparticle catalysts, cluster catalysts, and single-atom catalysts, we discuss the influence of structural regulation, such as adjustment of size and configuration, metal doping, defect engineering, and acid/base modification, on the structure–activity relationship in the process of catalytic oxidation at ambient temperature. Then, the effects of process conditions, such as initial concentration, space velocity, oxidation atmosphere, and humidity adjustment on catalytic activity, are summarized. It is further found that nanoparticle catalysts are most commonly used in ambient temperature catalytic oxidation. Additionally, ambient temperature catalytic oxidation is mainly applied in the removal of easily degradable pollutants, and focuses on ambient temperature catalytic ozonation. The activity, selectivity, and stability of catalysts need to be improved. Finally, according to the existing problems and limitations in the application of ambient temperature catalytic oxidation technology, new prospects and challenges are proposed.

The Decomposition of Dilute 1-Butene in Tubular Multilayer Dielectric Barrier Discharge Reactor: Performance, By-Products and Reaction Mechanism

“…CO selectivity(%) = CO selectivity + CO selectivity (5) where [C4H8]0 and [C4H8]i are the concentrations of 1-butene at the inlet and outlet of the TM-DBD reactor, respectively.…”

“…The cleavage of the double bonds of 1butene (1) and related isomer 2-butene could easily take place by ozonolysis via 1,3-dipolar cycloaddition to give a carbonyl compound and a carbonyl oxide commonly called Criegee intermediates [45]. For Path A, due to the asymmetric structure of 1-butene (1), two zwitterion species, 5-O and 2-O, could be formed along with formaldehyde (2) and propanal (5), respectively. Criegee intermediates 5-O and 2-O could be trapped by nucleophiles, such as N-oxides, in air plasma.…”

“…Criegee intermediates 5-O and 2-O could be trapped by nucleophiles, such as N-oxides, in air plasma. The generated species subsequently decomposed into related reduction products, propanal (5) and formaldehyde (2). With the aid of the active oxidants (i.e., • OH, O • ), aldehyde compounds could proceed through further oxidation to produce the related acid propionic acid (11) and formic acid (8) [46], which could go through a direct decarbonylation process to furnish CO and H 2 O. Additionally, after further oxidation of formic acid to carbonic acid (12), a decarboxylation reaction could take place to eliminate a carboxyl group and with the release of CO 2 .…”

“…Meanwhile, butenes are the typical gaseous pollutants in petrochemical waste gas, which are unwanted byproducts in dehydrogenation and unreacted monomers in polyreactions. Although butenes have low toxicity and exert little effect on human health, their emission into the atmosphere should be controlled to avoid secondary pollution mediated by photochemical reactions [5][6][7]. Therefore, it is imperative to develop appropriate technology to remove butenes before being emitted into the atmosphere.…”

Manipulation of Waste-Activated Carbon Absorbers as Efficient Carbocatalysts for H2S Selective Oxidation

“…Therefore, it is necessary to develop an effective styrene removal technology. Activated carbon has been widely used as a solid adsorbent for the adsorption of VOCs. − However, the waste-activated carbon produced after adsorbing saturated VOCs has technical difficulties, such as complex composition, high ash content, and poor thermal stability. Unfortunately, waste-activated carbon is difficult to collect and expensive to handle, and it is immediately burnt and landfilled, releasing massive volumes of nitrogen oxides and causing significant environmental damage. , As a result, recycling waste-activated carbon has emerged as a critical global concern.…”