Adsorption efficiency

Less propane and butanes are produced compared to natural gas Hquids by the adsorption process than are obtained normally for the same gas by the oil-absorption process. Because adsorption efficiency increases with a decrease in temperature, the adsorption cycle should operate at the lowest temperature that is economically feasible. 

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. 

There is a wide range in adsorption efficiency for inorganics. 

The total hydrocarbon reduction efficiency for the Rotor/Concentrator is the adsorption efficiency of the Rotor/Concentrator times the destruction efficiency of the oxidizer. 

The relationship between adsorption capacity and surface area under conditions of optimum pore sizes is concentration dependent. It is very important that any evaluation of adsorption capacity be performed under actual concentration conditions. The dimensions and shape of particles affect both the pressure drop through the adsorbent bed and the rate of diffusion into the particles. Pressure drop is lowest when the adsorbent particles are spherical and uniform in size. External mass transfer increases inversely with d (where, d is particle diameter), and the internal adsorption rate varies inversely with d Pressure drop varies with the Reynolds number, and is roughly proportional to the gas velocity through the bed, and inversely proportional to the particle diameter. Assuming all other parameters being constant, adsorbent beds comprised of small particles tend to provide higher adsorption efficiencies, but at the sacrifice of higher pressure drop. This means that sharper and smaller mass-transfer zones will be achieved. 

Adsorption efficiency can be optimized by using finer particle size products which will improve the diffusion rate to the surface of the activated carbon. However, there is a tradeoff in using finer particles with pressure drop and, hence energy use. Note that during start-up of an activated carbon filter bed, a bed expansion of 25 to 35 % is recommended in order to remove soluble matter and to stratify particles in order to ensure that the MTZ is maintained when future backwashing is performed. 

Adsorption plant operation is very sensitive to the temperature of the incoming gas. Generally, the adsorption efficiency decreases as the temperature increases. 

Granular activated carbon (GAC) and peat adsorption are two tertiary wastewater filtration processes using GAC and peat, respectively, as the media for removing not only insoluble suspended solids, but also dissolved organic solids.8 Tables 7.14 and 7.15 report the adsorption efficiencies for... 

Since Diaz and Balkus first attempted to immobilize enzymes on mesoporous MCM-41 [101], several research groups have investigated the influence of various physical factors such as pore size, ambient pH, and ionic strength, on the adsorption efficiency of proteins [102-118]. This research revealed the general tendencies of protein adsorption behavior and outlines for successful immobilization of proteins onto mesoporous materials. As one of the representative examples, systematic... 

Fig. 4.13 Influence of factors on protein adsorption efficiency on mesoporous materials. Adapted from [37], A. Vinu etal.J. Nanosci. Nanotechnol. 2006, 6, 1510.

Kowalska M, Gtiler H, Cocke DL (1994) Interactions of clay minerals with organic pollutants. Sci Total Environ 141 223-240 Kukkadapu RK, Boyd SA (1995) Tetramethylphosphonium-smectite and tetramethylammonium-smectite as adsorbents of aromatic and chlorinated hydrocarbons - effect of water on adsorption efficiency. Clays Clay Miner 43 318-323... 

Adsorption of reactive dye K-2BP by immobilized Aspergillus fumigatus in Na-carboxymethyl-cellulose (Na-CMC), Na-ALG, PVA, and CTS was studied by Wang et al. [61]. The dye culture mediums were almost completely decolorized 48 h using CTS and Na-CMC immobilized beads. The adsorption efficiency of SA and PVA-SA immobilized beads exceeded 92 and 79.8% in 48 h, respectively. 

The presence of a thermodynamically incompatible polysaccharide in the aqueous phase can enhance the effective protein emulsifying capacity. The greater surface activity of the protein in the mixed biopolymer system facilitates the creation of smaller emulsion droplets, i.e., an increase in total surface area of the freshly prepared emulsion stabilized by the mixture of thermodynamically incompatible biopolymers (see Figure 3.4) (Dickinson and Semenova, 1992 Semenova el al., 1999a Tsapkina et al., 1992 Makri et al., 2005). It should be noted, however, that some hydrocolloids do cause a reduction in the protein emulsifying capacity by reducing the protein adsorption efficiency as a result of viscosity effects. 

Solubility. The solubility of the polymers has not been emphasized sufficiently in reviews and the original literature reports. The reason for this omission may be the extremely low solubility of all of the polymers, except Tenax, in the solvents normally used for elution and purification. The adverse effects of polymer solubility are (1) even very small amounts of dissolved polymer can interfere with the subsequent chemical analyses and bioassays, and (2) dissolution of some of the polymer can change the surface characteristics both externally and internally such that reuse involves a polymer of much different adsorption efficiency. An example of the first adverse effect would be deterioration of the analytical capillary column when deposition followed by decomposition of the polymer occurs on the front end of the capillary. An extreme example of the second adverse effect is the dissolution of large amounts of Tenax when benzene is used in Soxhlet desorption. 

Kundu, S. and Gupta, A.K. (2006) Investigations on the adsorption efficiency of iron oxide coated cement (IOCC) towards As(V> kinetics, equilibrium and thermodynamic studies. Colloids and Surfaces A Physicochemical and Engineering Aspects, 273(1-3), 121-28. 

High humidity reduces adsorption efficiency of silica gel. 

Adsorption efficiency of silica gel decreases under high humidity. 

The amount of zinc(II) ions bound to the polymer was quite elegantly determined by the use of a zinc(II) selective fluorophore developed by the same group. [3] Adsorption of phosphates such as 5 -dAMP and 4-NPP, adenosine 3, 5 -cyclic-monophosphate (3, 5 -cAMP) and the corresponding dephosphorylated compounds, deoxyadenosine (dA) and 4-nitrophenol (4-NP) was studied. The polymer was stirred in a solution containing the studied guest in a buffered aqueous solution. The adsorption efficiency was determined by the decrease of the guest molecule concentrations by UV measurement. 

Cappelli, F., P.D. Goulden, J. Lawrence, and DJ. MacGregor. 1978. Determination of the adsorption efficiency of the organics carbon adsorbable standard method by dissolved organic carbon analysis. J. Environ. Sci. Health A 13 167-176. 

Toxicity The acute oral LD50 and dermal LD50 toxicity of toxaphene in rats are 40 and 600 mg/kg, respectively. Toxaphene is an active nerve poison and interferes with fluxes of cations across nerve cell membranes, which increases neuronal irritability and results in convulsions and seizures. Toxaphene also has been found to damage the lungs, liver, and kidney of animals and humans. Although the dermal adsorption efficiency of toxaphene is less than that of other organochlorines, its absorption is enhanced by fat and fat solvents. Toxaphene has been shown to cause cancer in pregnant animals and to induce birth defects.68... 

Using a constant corrosion rate multiplied by the adsorption efficiency measured as described above, the rate of hydrogen absorption into the metal was calculated, and susceptibility to HIC was assumed to be established once a critical hydrogen concentration (Hc) was reached. A more detailed discussion of this simple conservative model, including a description of the determination of Hc from mechanical experiments, is described elsewhere (33). The conservatism in the model arises from the assumption that all the hydrogen absorbed is retained by the metal rather than released by oxidation as the corrosion process proceeds through the metal. As was emphasized in the introduction, such a conservatism is acceptable in a model where safety is the primary requirement. The approach described would be too conservative for an industrial service model. 

The sulfur adsorption efficiency, nsAE> defined as the ratio of moles of sulfur dioxide consumed by the sulfation reaction to the moles of sulfur dioxide produced due to char combustion. The above equations will be utilized to analyze the parametric sensitivity of the fluidized-bed combustion operation. 

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