Adsorption capacity Table

Although a lot of research has been reported on the use of various carbonaceous materials in defluoridation, no known column or full-scale plant operation is easily available in open literature. One reason for this is that most carbonaceous materials show poor adsorption capacity (Table 4) for fluoride and therefore only laboratory-scale performances have so far been reported. Amorphous alumina supported on carbon nanotubes on the other hand show high capacity (28.7 mgF/g adsorbent) for fluoride and is therefore a promising material for drinking water defluoridation. 

Maximum adsorption capacity. 100 ml of mercury solutions the concentration of which varied from 100 to 1000 ppm were contacted with 50 mg of adsorbant at neutral pH to determine the maximum adsorption capacity (Table 1). The modified cellulose and com-stick powder adsorbed 46% and 49% of 1000 ppm mercury solution, which corresponds respectively to 920 mg/g of mercury/g of absorbant (4,6 nunole/g) and 980 mg/g (4,9 mmole/g). 

On the basis of the total amount of organic matter removed during the process, it was found that the activated carbon had adsorbed well above its adsorption capacity (Table 2). Tbe total amount of the adsorbed organic matter was determined as the difference of the integrals for the surface under the curves showing dependence of the organic matter concentration in the influent, respectively, and the volume of the wastewater passed through the system. 

The quantity of proteins adsorbed (egg or BSA blood albumin) may also be measured. Sodium bentonite has a higher adsorption capacity (Table 10.7) than calcium bentonite, which explains why it is preferred for treating wine. 

The availability of chemisorbed chlorine for substitution by other groups was examined by Puri et al. and Boehm. by refluxing the chlorinated carbons with 2.5 M sodium hydroxide and by treatment with ammonia, which indicated the substitution of chlorine by amino groups. The presence of amino groups imparted a basic character to the carbon surface, and there was a noticeable increase in the acid adsorption capacity (Table 1.18). Equivalence in chlorine eliminated, nitrogen... 

Table 8. Adsorption Capacity of Amberlite XAD-4 Polymeric Resin ...

The adsorptive capacity of activated carbon for some common solvent vapors is shown in Table 25-27. 

TABLE 25-27 Adsorptive Capacity of Common Solvents on Activated Carbons ... 

The pore size of Cs2.2 and Cs2.1 cannot be determined by the N2 adsorption, so that their pore sizes were estimated from the adsorption of molecules having different molecular size. Table 3 compares the adsorption capacities of Csx for various molecules measured by a microbalance connected directly to an ultrahigh vacuum system [18]. As for the adsorption of benzene (kinetic diameter = 5.9 A [25]) and neopentane (kinetic diameter = 6.2 A [25]), the ratios of the adsorption capacity between Cs2.2 and Cs2.5 were similar to the ratio for N2 adsorption. Of interest are the results of 1,3,5-trimethylbenzene (kinetic diameter = 7.5 A [25]) and triisopropylbenzene (kinetic diameter = 8.5 A [25]). Both adsorbed significantly on Cs2.5, but httle on Cs2.2, indicating that the pore size of Cs2.2 is in the range of 6.2 -7.5 A and that of Cs2.5 is larger than 8.5 A in diameter. In the case of Cs2.1, both benzene and neopentane adsorbed only a little. Hence the pore size of Cs2.1 is less than 5.9 A. These results demonstrate that the pore structure can be controlled by the substitution for H+ by Cs+. 

ZSM-5 and ZSM-11 samples were prepared as previously described (11) using tetrapropy 1 ammonium hydroxide and tetrabutyl ammonium bromide, respectively. The nature and crystallinity of the materials were verified by X ray diffraction, ir spectroscopy of lattice vibrational bands ( 1 2 ), n-hexane adsorption capacity at room temperature and constraint index (13) measurements. All samples correspond to highly crystalline ZSM-5 or ZSM-11 materials. The chemical compositions of the samples as determined from chemical analysis of A1 and Na contents, are given in table 1. 

At a given pressure, the amounts of xenon adsorbed by the different phases allow one to estimate their relative crystallinities, with respect to the most crystalline sample, P32. These results are presented in Table 1. The isotherms of Po and P5 overlap, which implies that both intermediates have the same adsorption capacity. Although the X-ray diffraction and scanning electron microscopy... 

Table 21.2 Ratio of adsorptive capacity (A, mgg ) of enterosorbents Enterosgel (ESG)/ Carboline (CARBO) adjusted to their daily doses...

Table 21.8 Adsorptive capacity of Enterosgel and carbon enterosorbent Carboline towards some antituberculosis and antiretroviral preparations...

The fractality index a obtained from analysis of SANS curves correlates with the adsorption capacity of carbon materials for unconjugated bilirubin adsorbed from HSA solution in micro-column single-pass experiments (Table 29.2) [10]. 

Table 29.2 Correlation between fractality of carbonic sorbents (a) and their adsorption capacity towards unconjugated bilirubin (mg/g) from albumin-containing solution...

The most important property of adsorbent materials, the property that is decisive for the adsorbent s usage, is the pore structure. The total number of pores, their shape, and size determine the adsorption capacity and even the dynamic adsorption rate of the material. Generally, pores are divided into macro-, rneso- and micropores. According to IUPAC, pores are classified as shown in Table 2.2. 

The porous volumes measured by N2 adsorption are listed in Table 3. After the boronation, the total porous volumes (Vt) of the samples increase, corresponding to the increase of benzene adsorption capacity mentioned above. This should be resulted from the following aspects (1) The average mass of zeolite crystallite decrease and the number of crystal particles in unit weight of sample increases after the boronation owing to a limited introduction of trivalent atoms and Na+cations as counterions, as well as a severe dissolution of silicon. Thus, the total porous volume (mL/g) and the adsorption capacity increase. (2) The transformation of pore size occurs during the boronation. As shown in Table 3, the mesoporous volumes increase and the microporous volumes decrease after the boronation, meaning that some micropores are developed into mesopores due to the removal of silicon from the framework. This is also one of the important reasons why the total porous volumes as well as the adsorption capacities increase after the boronation. 

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