Organic compounds over active carbon

Chemical Vapor Deposition of Organic Compounds over Active Carbon Fiber To Control Its Porosity and Surface Function... 

Dowex Optipore is a polymeric adsorbent used to treat chlorinated volatile organic compound (CVOC) contaminated off-gas streams from remediation processes such as air stripping of groundwater and soil vapor extraction. According to the vendor Dowex Optipore adsorbent has the following advantages over activated carbon ... 

Air samples were collected on 11.5 cm x 6 mm OD x4mm ID three-phase Carbotrap 300 thermal desorption tubes (Supelco) or four-phase Carbotrap 400 tubes. These sorbent tubes house a sequence of graphitized carbon and molecular sieves of increasing activity that sorb volatile and semi-volatile organic compounds over a molecular size range from Q to C30. 

This process was developed by a division of Nobel Industries, a major chemical corporation in Sweden. The heart of the process is a unique adsorbent called Bonopore 110, which is described as a microporous, crosslinked polymer in the form of spherical particles with a narrow size distribution (Heinegard, 1988). The particles have a pore diameter of approximately 80 A, a. specific surface area of about 800 sq m per gram, and a diameter of about 0.5 mm. Adsorption isotherms for four typical organic compounds and Bonopore 110 are given in Figure 12-48. The polymer adsorbent is claimed to have the following advantages over activated carbon ... 

CVD by organic compounds pyrolysis over active carbon fiber. 

Human-made sources cover a wide spectrum of chemical and physical activities and are the major contributors to urban air pollution. Air pollutants in the United States pour out from over 10 million vehicles, the refuse of over 250 million people, the generation of billions of kilowatts of electricity, and the production of innumerable products demanded by eveiyday living. Hundreds of millions of tons of air pollutants are generated annu ly in the United States alone. The five main classes of pollutants are particulates, sulfur dioxide, nitrogen oxides, volatile organic compounds, and carbon monoxide. Total emissions in the United States are summarized by source categoiy for the year 1993 in Table 25-10. 

Case 2 - The Hyde Park Landfill site, located in an industrial complex in the extreme northwest corner of Niagara, New York, was used from 1953 to 1975 as a disposal site for an estimated 80,000 tons of chemical waste, including chlorinated hydrocarbons. A compacted clay cover was installed in 1978 over the landfill and a tile leachate collection system was installed in 1979. Hazardous compounds such as ortho-, meta- and para-chlorobenzoic acid toluene ortho- and meta-chlorotoluene 3,4-dichlorotoluene and 2,6-dichlorotoluene were detected in the leachate (Irvine et al., 1984). Since 1979, the existing leachate treatment system has used activated carbon as the technology for removing organic carbon. Although... 

Modification techniques for activated carhon were used to increase the removal capacity by surface adsorption and to improve the selectivity to volatile organic compounds (VOCs). Modified activated carbons (MACs) were prepared by modifying the purified activated carbon with various acids or bases. The effects of adsorption capacity and modified contents on the textural properties of the MACs were investigated. Furthermore, VOC adsorption and desorption experiments were carried out to determine the relationship between the adsorption capacity and the chemical properties of the adsorbents. High adsorption capacity for the selected VOCs was obtained over lwt%-H3P04/AC (lwt%-PA/AC). As a result, MAC was found to be very effective for VOC removal by adsorption with the potential for repeated use through desorption by simple heat treatment. 

Nickel reduced from the carbonate at 450° C. has no action upon a mixture of hydrogen and oxygen at ordinary temperatures, but if distributed over nine times its weight of inert substance it equals colloidal palladium in activity. It is still more active towards organic compounds if reduced at a lower temperature, such as 310° C.6... 

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