Volatile organic compounds VOCs oxidation

As discussed in detail throughout this book, there is rich and complex chemistry involving volatile organic compounds (VOCs), oxides of nitrogen, and ozone in ambient air. One might therefore anticipate similar chemistry in indoor air environments, and although there are far fewer studies, this does indeed appear to be the case. Weschler and Shields (1997b) and Wolkoff et al. (1997, 1999) review VOC-NOx chemistry that could potentially be important in indoor air enviro-ments and the implications for human exposures. 

Environmental applications of metal-doped carbon gels can be divided between reactions carried out in the gas and aqueous phases. The former group includes volatile organic compound (VOC) oxidation (e.g., toluene and xylene oxidation) and NO reduction. The latter group includes the catalytic wet air oxidation (CWAO) of aniline solutions and advanced oxidation processes (AOPs) (e.g., catalytic ozonation and photooxidation of pollutants). 

Foam manufacturing follows two alternative principles replication or foaming. The replication method was already invented in 1963 by Schwarzwalder and Somers [32], but it is still the most common technique used in industry. Schwarzwalder and Somers already addressed the potential of foams as catalysts and catalyst carriers in their patent. They gave an example of the preparation of a bulk catalyst containing vanadia that was used in volatile organic compound (VOC) oxidation. 

For applications in heterogeneous catalysis, perovskites generally comprise a lanthanide (La is the most common) in the A site and a transition metal (Mn, Co, etc.) in the B site. The efficiency of such perovskite oxides, with or without cationic substitution, is well documented for a variety of catalytic reactions [2-9]. Actually, the specific catalytic activities of perovskites were sometimes found to be comparable to that of noble metals for various oxidation reactions. Early on, Arai et al. illustrated the activity of strontium-substituted LaMnOs, which was found to be superior to that of Pt/alumina catalysts at a conversion level below 80% [5]. Several authors have also discussed the application of La-based perovskite oxides as catalysts for volatile organic compound (VOC) oxidation (see, for example. Refs [10-14]). Zhang et al. have also shown that some perovskite oxides substituted with Pd or Cu are also good catalysts for the reduction of NO by CsHg [15-18] and by CO [19,20]. More recently, Kim et al. studied the effect of Sr substitution in LaCoOs and LaMnOs perovskites for diesel oxidation (DOC) and lean NO, trap (LNT) processes [9]. The observations made by these authors clearly indicate that the perovskites used in their study could efficiently outperform Pt-based catalysts. Typically, Lai. Sr cCoOs catalysts achieved higher... 

Tsou, J., Pinard, L. and Magnoux, P. (2003). Catalytic oxidation of volatile organic compounds (VOCs) Oxidation of o-xylene over Pt/HBEA catalysts, Appl. Catal. B Environ., 46, pp. 371-379. 

In 1990, a test using scrap tires (2x2 in. I DE) to generate steam for electricity was conducted at the Elexsys plant. The I DE replaced 20% of the plant s coal. Results showed that IDE is an environmentally sound fuel. Particulate emissions were reduced by the lower ash content of IDE, volatile organic compounds (VOC) were reduced because of more efficient burning of I DE compared to coal, and carbon dioxide emissions were reduced because I DE contains half the fixed carbon found in coal. Nitrogen oxide, chlorine emissions, and metals were also reduced, and ferrous metals and dioxins were nondetectable (7). 

Emissions to the atmosphere from ammonia plants include sulfur dioxide (SOj), nitrogen oxides (NOJ, carbon monoxide (CO), carbon dioxide (COj), hydrogen sulfide (HjS), volatile organic compounds (VOCs), particulate matter, methane, hydrogen cyanide, and ammonia. The two primary sources of pollutants, with typical reported values, in kilograms per ton (kg/t) for the important pollutants, are as follows ... 

Volatile organic compounds (VOCs) include organic compounds with appreciable vapor pressure. They make up a major class of air pollutants.I his class includes not only pure hydrocarbons but also partially oxidized hydrocarbons (organic acids, aldehydes, ketones), as well as organics containing chlorine, sulfur, nitrogen, or other atoms in the molecule. 

At pulp and paper mills, air emissions from both process and combustion units are regulated under the National Ambient Air Quality Standards (NAAQS) and the State Implementation Plans (SIP) that enforce the standards. States may implement controls to limit emissions of particulate matter (PM), nitrogen oxides (NO ), volatile organic compounds (VOCs), and sulfur dioxide (S02). 

Photocatalytic oxidation can be an effective way of removing pollutants in the gas phase, such as NOx, SOx, and volatile organic compounds (VOCs). 

Environmental applications Oxidation of volatile organic compounds (VOCs) [114] Decomposition of organic dyes [115] Removal of aqueous phenol [116] Superwetting nanowire membranes for selective absorption [117]... 

SWITGTHERM A catalytic process for oxidizing volatile organic compounds (VOCs). It involves regenerative heat exchange, which permits autothermal operation at VOC concentrations in the range 250 to 650 ppm. Developed in Poland and now used in over 100 installations there. 

The mechanisms for the NMHCs (except DMS) required to fully characterise OH chemistry were extracted from a recently updated version of the Master Chemical Mechanism (MCM 3.0, available at http //mcm.leeds.ac.uk/MCM/). The MCM treats the degradation of 125 volatile organic compounds (VOCs) and considers oxidation by OH, NO3, and O3, as well as the chemistry of the subsequent oxidation products. These steps continue until CO2 and H2O are formed as final products of the oxidation. The MCM has been constructed using chemical kinetics data (rate coefficients, branching ratios, reaction products, absorption cross sections and quantum yields) taken from several recent evaluations and reviews or estimated according to the MCM protocol (Jenkin et al., 1997, 2003 Saunders et al., 2003). The MCM is an explicit mechanism and, as such, does not suffer from the limitations of a lumped scheme or one containing surrogate species to represent the chemistry of many species. 

Air/liquid (A/L) interface, adsorption of surfactants at, 24 133-138 Air mass zero (AMO) spectrum, 23 37 Air monitoring, for hydrazine, 13 589 Air oxidized pan, 11 194 Air-path XRF, in fine art examination/ conservation, 11 403—404 Air pollutants. See also Nitrogen oxides (NO j Particulate matter Sulfur oxides (SOJ Volatile organic compounds (VOCs) air toxics, 1 789, 801-802 carbon monoxide, 1 789, 798 common, 26 667 criteria pollutants, l 813t indoor, 1 802-805, 820-823, 821t lead, 1 789, 801... 

Paulis, M Gandia, LM Gil, A Sambeth, J Odriozola, JA Montes, M. Influence of the surface adsorption-desorption processes on the ignition curves of volatile organic compounds (VOCs) complete oxidation over supported catalysts, Appl. Catal, B Environmental, 2000, Volume 26, Issue 1, 37-46. 

There are six primary in-plant control methods for removal of priority pollutants and pesticides in pesticide manufacturing plants. These methods include steam-stripping, activated carbon adsorption, chemical oxidation, resin adsorption, hydrolysis, and heavy metals separation. Steam-stripping can remove volatile organic compounds (VOCs) activated carbon can remove semi volatile organic compounds and many pesticides and resin adsorption, chemical oxidation, and hydrolysis can treat selected pesticides [7]. Heavy metals separation can reduce toxicity to downstream biological treatment systems. Discussion of each of these methods follows. 

The chemistry of the troposphere (the layer of the atmosphere closest to earth s surface) overlaps with low-temperature combustion, as one would expect for an oxidative environment. Consequently, the concerns of atmospheric chemistry overlap with those of combustion chemistry. Monks recently published a tutorial review of radical chemistry in the troposphere. Atkinson and Arey have compiled a thorough database of atmospheric degradation reactions of volatile organic compounds (VOCs), while Atkinson et al. have generated a database of reactions for several reactive species with atmospheric implications. Also, Sandler et al. have contributed to the Jet Propulsion Laboratory s extensive database of chemical kinetic and photochemical data. These reviews address reactions with atmospheric implications in far greater detail than is possible for the scope of this review. For our purposes, we can extend the low-temperature combustion reactions [Equations (4) and (5)], whereby peroxy radicals would have the capacity to react with prevalent atmospheric radicals, such as HO2, NO, NO2, and NO3 (the latter three of which are collectively known as NOy) ... 

Among the chemicals regarded as air pollutants under the dehni-tion are carbon monoxide, oxides of nitrogen, sulfur dioxide, particulate matter, volatile organic compounds (VOCs), ozone, and lead. 

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