Carbon disulfide adsorption

Table 12-31 Design and Operating Data for Ruidized Bed Carbon Disulfide Adsorption Plant (Rowson, 1963 Anon., 1963) ...

The effects of adsorption and desorption on the performance of fluidized beds are discussed elsewhere. Adsorption of carbon disulfide... 

H. M. Rawson, Fluid Bed Adsorption of Carbon Disulfide, British Chemical Engineering, 8(3) 180 (March 1963). 

SO as to end the air mixture to adsorber No. 2. The system is then fully automatic. Solvents which have been successfully recovered by the activated carbon adsorption method include methanol, ethanol, butanol, chlorinated hydrocarbons including perchlorethylene, which boils at 121 C (250 °F), ethyl ether, isopropyl ether, the acetates up to amyl acetate, benzene, toluene, xylene, mineral spirits, naphtha, gasoline, acetone, methyl ethyl ketone, hexane, carbon disulfide, and others. 

The hydroxyl groups of the cellulose appear to be somewhat acidic. While studies of the composition of alkali cellulose and adsorption of sodium hydroxide have not clearly proved the presence of any sodium compound in alkali cellulose, the reactions of alkali cellulose with carbon disulfide and with etherifying agents would seem to justify the assumption that such an intermediate exists or that the hydroxyl hydrogen at least ionizes. This view is strengthened by the fact that the rate of etherification is proportional to a high power of the concentration of alkali.19... 

The effects of adsorption and desorption on the performance of fluidized beds are discussed elsewhere. Adsorption of carbon disulfide vapors from air streams as great as 300 nr/s (540,000 ft3/min) in a 17-m- (53-ft-) diameter unit has been reported by Avery and Tracey ( The Application of Fluidized Beds of Activated Carbon to Recover Solvent from Air or Gas Streams, Tripartate Chemical Engineering Conference, Montreal, Sept. 24, 1968). 

Air Adsorption onto charcoal desorption with carbon disulfide GC/FID (OSHA Method 05) 0.11 ppm for 10 L sample 96 (8.5% RSD) OSHA 1979... 

Air Adsorption onto charcoal desorption with carbon disulfide, containing internal standard if desired GC/FID (NIOSH method 1003) 0.7 mg/m for 15 L sample 97 at 120-493 mg/m NIOSH 1994... 

We then designed model studies by adsorbing cinchonidine from CCU solution onto a polycrystalline platinum disk, and then rinsing the platinum surface with a solvent. The fate of the adsorbed cinchonidine was monitored by reflection-absorption infrared spectroscopy (RAIRS) that probes the adsorbed cinchonidine on the surface. By trying 54 different solvents, we are able to identify two broad trends (Figure 17) [66]. For the first trend, the cinchonidine initially adsorbed at the CCR-Pt interface is not easily removed by the second solvent such as cyclohexane, n-pentane, n-hexane, carbon tetrachloride, carbon disulfide, toluene, benzene, ethyl ether, chlorobenzene, and formamide. For the second trend, the initially established adsorption-desorption equilibrium at the CCR-Pt interface is obviously perturbed by flushing the system with another solvent such as dichloromethane, ethyl acetate, methanol, ethanol, and acetic acid. These trends can already explain the above-mentioned observations made by catalysis researchers, in the sense that the perturbation of initially established adsorption-desorption equilibrium is related to the nature of the solvent. 

The NIOSH methods, in general, are based on adsorption of compounds in the air over a suitable adsorbent, desorption of the adsorbed analytes into a desorbing solvent, and, subsequently, their determination by GC using a suitable detector. A known volume of air is drawn through a cartridge containing coconut shell charcoal. The adsorbed compounds are desorbed into carbon disulfide, propanol, benzene, toluene, hexane, or methylene chloride. An aliquot of the solvent extract is then injected onto the GC column. FID is the most commonly used detector. Other detectors, such as ECD, ELCD, or PID have been used, however, in the method development of certain compounds. NIOSH method numbers and the analytical techniques are presented in Table 2.9.3. 

Carbon disulfide At room temperature, only physisorption occurs on Pt film [2], while partly reversible adsorption takes place on Pd film [31 with 0.7 chemisorbed coverage. The adsorption is believed to be dissociative over this latter surface [3]. Hydrogen can be adsorbed over CS2-covered Pt film [2] but cannot over CS2-covered Pd film [3]. Thiophene At room temperature, chemisorption occurs through the lone pair of sulfur... 

The porous nature of the Qo crystals has now been examined in more detail by Kaneko and his co-workers (Setoyama et al., 1996 Thess et al., 1996). The Cw powder was recrystallized from carbon disulfide and then studied before and after annealing by heat treatment The nitrogen adsorption measurements revealed that the recrystallized material was both microporous and mesoporous the mesoporosity was completely removed by heat treatment, but the sample remained microporous. Since the micropores and the molecules appeared to be of similar size, it was concluded that the micropores were largely in the form of molecular defects and lattice vacancies. 

These methods suggested in the present form by Caunt83) rely on inhibition (retardation) effects of strong catalyst poisons on polymerization. Typical poisons potentially usable for this purpose are carbon oxides, carbonyl sulfide, carbon disulfide, acetylenes and dienes. All these substances exhibit a strong unsaturation they have either two double bonds or one triple bond. Most of the works devoted to application of the poisons to determination of active centers 10,63 83 102 1O7) confirm a complicated nature of their interaction with the catalytic systems. To determine the active centers correctly, it is necessary to recognize and — as much as practicable — suppress side processes, such as physical adsorption and chemisorption on non-propagative species, interaction with a cocatalyst, oligomerization and homopolymerization of the poison and its copolymerization with the main chain monomer. 

Although Roy and Griffin (1985) did not conduct adsorption studies, they classified carbon disulfide as a mobile solvent exhibiting a low tendency to be retained by soils. Carbon disulfide released to soils in spills should rapidly volatilize to the atmosphere, but a portion of the compound remaining on soil surfaces could be available for transport into groundwater since it does not have much affinity for soil particles. Farwell et al. (1979) indicated that carbon disulfide volatilizes from a variety of soils, although rates were not provided. 

The primary method of analyzing carbon disulfide in air is by adsorption on an activated charcoal tube followed by solvent elution for subsequent quantification. GC equipped with either an electron capture detector (ECD), photo-ionization detector (PID), or FPD has been used for measuring carbon disulfide after elution from the solid phase. Detection limits of low ppm levels of carbon disulfide in the air sample were achieved with these techniques (McCammon et al. 1975 Peltonen 1989 Smith and Krause 1978 UK/HSE 1983). NIOSH has recommended GC/FPD (method 1600) for determining carbon disulfide in air. The range of quantification is 3-64 ppm for a 5-L air sample (NIOSH 1984b). 

UK/HSE. 1983. Carbon disulfide in air Laboratory method using charcoal adsorption tubes, solvent desorption and gas chromatography. London, England United Kingdom, Health and Safety Executive, Occupational Medicine and Hygiene Laboratory. MDHS Report No. 15. 

Waldman M, Vanecek M. 1982. Volumetric method for the determination of carbon disulfide in air using personal sampling and adsorption by active charcoal. Ann Occup Hyg 25 5-15. 

Activated carbon cartridges are opened after the sparging operation and the front and back portions of the carbon are transferred into vials equipped with Mininert valve seal. One milliliter of carbon disulfide is introduced through the septum by means of a syringe (to prevent losses of volatiles due to heat of adsorption). The vials are allowed to stand at room temperature for 30 min with periodic shaking. A 1-/JL aliquot is withdrawn and injected into the gas chromatograph. 

For BTEX analysis in air with either active or passive " sampling, carbon disulfide is the most used extracting agent due to its high adsorption capacity that displaces other molecules... 

MEASUREMENT METHODS Resin adsorption tube carbon disulfide gas chromatography. 

GSC is based on adsorption of gaseous substances on solid surfaces. Distribution constants are generally much larger than those for GLC. As a result, GSC is useful for the separation of species that are not retained by gas-liquid columns, such as the components of air, hydrogen sulfide, carbon disulfide, nitrogen oxides, carbon monoxide, carbon dioxide, and the rare gases. 

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