Adsorbents activated carbon

Activated carbons contain chemisorbed oxygen in varying amounts unless special cate is taken to eliminate it. Desired adsorption properties often depend upon the amount and type of chemisorbed oxygen species on the surface. Therefore, the adsorption properties of an activated carbon adsorbent depend on its prior temperature and oxygen-exposure history. In contrast, molecular sieve 2eohtes and other oxide adsorbents are not affected by oxidi2ing or reducing conditions. 

The removal of volatile organic compounds (VOC) from air is most often accompHshed by TSA. Air streams needing treatment can be found in most chemical and manufacturing plants, especially those using solvents. At concentrations from 500 to 15,000 ppm, recovery of the VOC from steam used to regenerate activated carbon adsorbent thermally is economically justified. Concentrations above 15,000 ppm ate typically in the explosive range and... 

The commercialization by Kureha Chemical Co. of Japan of a new, highly attrition-resistant, activated-carbon adsorbent as Beaded Activated Carbon (BAC) allowed development of a process employing fluidized-bed adsorption and moving-bed desorption for removal of volatile organic carbon compounds from air. The process has been marketed as GASTAK in Japan and as PURASIV HR (91) in the United States, and is now marketed as SOLD ACS by Daikin Industries, Ltd. 

Tabic 3. Some Studies on Methane Storage using Amoco Type KOH Activated Carbon Adsorbents... 

Table 2 provides a list of issues you should address when considering the acquisition of an adsorber. Also, consult the references cited at the end of this section for more detailed information and guidance on adsorber equipment selection criteria. Table 3 provides a list of vendors that supply activated carbon adsorbers. 

Will you need to filter the waste stream to remove contaminants that would clog the activated carbon adsorbent ... 

Subsequently, biological/physical treatment of leachate with an activated carbon-enhanced sequencing batch bioreactor (PAC-SBR) was analyzed to determine whether the improved treatment by simultaneous adsorption and biodegradation in the SBR would produce an acceptable effluent without post-treatment in the existing granular activated carbon adsorber (Ying et al., 1986). 

It was not nndl the 1950s that detonation flame arresters made of crimped metal ribbon elements were developed and began to be used more freqnendy (Binks 1999). The major impetus for die use of crimped metal ribbon detonation flame arresters in the US was the enactment of clean air legislation (Clean Air Act of 1990) which inadvertently created a safety problem by requiring reductions in volatile organic compound (VOC) emissions. To do this, manifolded vent systems (vapor collection systems) were increasingly installed in many chemical process industry plants which captured VOC vapors and transported them to suitable recovery, recycle, or destruction systems. This emission control requirement has led to the introdnction of ignition risks, for example, from a flare or via spontaneous combustion of an activated carbon adsorber bed. Multiple... 

The installation of flame arresters shonld also be considered for vacnnm pnmps, activated carbon adsorbers, etc. which emit flammable vapors and/or can serve as ignition sonrces. 

Vapor Collection System A piping system to which vessels are connected, that collects vapors from these vessels and directs them to environmental control equipment snch as flares, incinerators, scmbbers, and activated carbon adsorbers. 

Activated carbon is often used as a catalyst support because of its high surface area and porosity. For example, Uchida et al. (1993) utilized activated carbon adsorbent as support for TiOz photocatalysts. It is reported that the adsorptive action of the activated carbon support enables the organic pollutants to concentrate around the loaded Ti02, resulting in a high photocatalytic degradation rate. 

For the preparation of Langmuir-Blodgett multilayers, a Joyce-Loebl Model 4 trough was used. The polymer was spread from a chloroform solution at a concentration of approximately 1 mg/ml. The de-ionized water subphase was passed through an activated carbon adsorber and then distilled in a glass still. Before deposition the... 

Supercritical fluid extraction (SFE) is a suitable process for many separation problems. The regeneration of the supercritical fluid is as important as the extraction step itself Therefore this paper presents a method to do this in a more isobaric way than the customary pressure reduction regeneration. For the example of soil remediation we have investigated the activated carbon regeneration of supercritical carbon dioxide loaded with the low-volatile polycyclic aromatic hydrocarbon (PAH) pyrene. Characteristics of supercritical fluid extraction for soil remediation are elevated temperatures and pressures up to 370 K and 300 bar. For this reason adsorption isotherms of pyrene on activated carbon up to these conditions are measured first. Subsequently this method is used to regenerate carbon dioxide in a closed solvent cycle plant with a 4 1 extractor. An economic analysis using these results indicate that the soil remediation costs will decrease for about 20 - 30 % by means of an activated carbon adsorber. 

For metal-on-carbon systems two aspects should be noted (i) metals and sulfided metals can act as sources of spiltover hydrogen species, and (ii) as active carbon adsorbs hydrogen by itself at high temperatures [T > 300°C (75)], the effect of spillover is to increase the rate of uptake but not the extent. With the inorganic oxides, spillover most often results in an increase in the amount of adsorption. 

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