Adsorbents granular activated carbon

Removal of Refractory Organics. Ozone reacts slowly or insignificantly with certain micropoUutants in some source waters such as carbon tetrachloride, trichlorethylene (TCE), and perchlorethylene (PCE), as well as in chlorinated waters, ie, ttihalomethanes, THMs (eg, chloroform and bromoform), and haloacetic acids (HAAs) (eg, trichloroacetic acid). Some removal of these compounds occurs in the ozone contactor as a result of volatilization (115). Air-stripping in a packed column is effective for removing some THMs, but not CHBr. THMs can be adsorbed on granular activated carbon (GAG) but the adsorption efficiency is low. 

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 may also be replaced with new carbon and disposal of the exhausted carbon Most adsorbers are pressure vessels constructed in carbon steel, stainless steel or plastic. Large systems for drinking water are often eonstructed in concrete. In some cases, a moving or pulsed bed adsorber is employed to optimixe the use of the granular activated carbon. 

Adsorption, which utilizes the ability of a solid adsorbent to adsorb specific components from a gaseous or a liquid solution onto its surface. Examples of adsorption include the use of granular activated carbon for the removal of ben-zene/toluene/xylene mixtures from underground water, the separation of ketones from aqueous wastes of an oil refinery, aad the recovery of organic solvents from the exhaust gases of polymer manufacturing facilities. Other examples include the use of activated alumina to adsorb fluorides and arsenic from metal-finishing emissions. 

The activated carbon is often chosen as granular carrier and is referred to as granular activated carbon (GAC) or biological activated carbon (BAC). This support is characterized by a strong propensity to adsorb the dyes and is a good candidate for biofilm formation, because of its natural organic matrix. The marked propensity to adsorb dyes contributes to increase the tolerance to shock loadings. In fact, under transient conditions the free surface of the AC acts as a temporary buffer for the dye, which is eventually released as dye disappears. 

Detailed accounts of fibers and carbon-carbon composites can be found in several recently published books [1-5]. Here, details of novel carbon fibers and their composites are reported. The manufacture and applications of adsorbent carbon fibers are discussed in Chapter 3. Active carbon fibers are an attractive adsorbent because their small diameters (typically 6-20 pm) offer a kinetic advantage over granular activated carbons whose dimensions are typically 1-5 mm. Moreover, active carbon fibers contain a large volume of mesopores and micropores. Current and emerging applications of active carbon fibers are discussed. The manufacture, structure and properties of high performance fibers are reviewed in Chapter 4, whereas the manufacture and properties of vapor grown fibers and their composites are reported in Chapter 5. Low density (porous) carbon fiber composites have novel properties that make them uniquely suited for certain applications. The properties and applications of novel low density composites developed at Oak Ridge National Laboratory are reported in Chapter 6. 

Wong, D.C.L. van Compemolle, R. Nowlin, J.G. O Neal, D.L. Johnson, G.M. Use of supercritical fluid extraction and fast ion bombardment mass spectrometry to identify toxic chemicals from a refinery effluent adsorbed onto granular activated carbon. Chemosphere 1996, 32, 621. 

Equipment cost for industrial activated carbon systems were provided in undated vendor material. The Model 4 system contains two 4-ft-diameter adsorbers and contains 2000 lb of granular activated carbon. The Model 8 system has two 8-ft-diameter adsorbers and contains 6000 to 10,000 lb of granular activated carbon. The Model 10 system has two 10-ft-diameter adsorbers, and the Model 12 system contains two 12-ft-diameter adsorbers. Both units contain 20,000 lb of granular activated carbon (D15749X, pp. 19-22). Estimated capital costs for the systems are given in Table 1. 

We have an excellent activated carbon of fiber morphology, so called activated carbon fiber ACF[3]. This ACF has considerably uniform slit-shaped micropores without mesopores, showing characteristic adsorption properties. The pore size distribution of ACF is very narrow compared with that of traditional granular activated carbon. Then, ACF has an aspect similar to the regular mesoporous silica in particular in carbon science. Consequently, we can understand more an unresolved problem such as adsorption of supercritical gas using ACF as an microporous adsorbent. 

De Laat J, Dore M, Mallevialle J. Effects of preozonation on the adsorbability and biodegradability of aquatic humic substances and on the performance of granular activated carbons filters. Water Res 1991 25 151-164. 

Matsunaga, T., Nakasono, S. and Masuda, S. (1992b) Electrochemical sterilization of bacteria adsorbed on granular activated carbon. FEMS Microbiol. Lett. 93, 255-260. 

Determine the Freundlich and Langmuir isotherm coefficients for the following adsorption test data on granular activated carbon (GAC). The liquid volume used in the batch adsorption tests was 1 L. The initial concentration of the adsorbate in solution was 3.37 mg/L. Equilibrium was obtained after 7 days. 

Hand, D. W., et al. (1997). Predicting the performance of fixed-bed granular activated carbon adsorbers, Water Science Technol, Proc. 19961st Int. Specialized Conf. on Adsorption in the Water Environment and Treatment Processes Shirahama, Japan, Nov. 5-8, 1996, 35, 7, 235-241. Elsevier Science Ltd., Oxford, England. 

In order to treat effluents characterized by metallic and organic pollutants, an association of two different adsorbents, sugar beet pulp and granular activated carbon, is investigated. In a first step, equilibrium data are determined for each adsorbent and mono-component solutions. Then, multi-metallic and oiganic-metal solutions are tested to determine some inhibitions or special selectivities. Finally, it is shown that the association of sugar beet pulp for metal removal, and activated carbon for organic elimination, is efficient to treat complex wastewaters. 

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