Activated coconut charcoal

Fig. 4.2 Adsorption isotherms of benzene at 25°C on (1) a charcoal from anthracite coal, activated to 56% yield (2) an activated coconut charcoal. (After Cadenhead and Everett.)...

Table V compares the degradation of total 2,4-D and 2,4,5-T (n-butyl esters and acids) over six years of observations In the Kansas and Florida locations. Although the rates of application were similar, the method of application, preplant Incorporation versus subsurface Injection, resulted In significant differences In the Initial concentrations of herbicides In the plots. The acid of 2,4,5-T comprised most of the total residue after the first two years. Although some residues were recovered, especially In later years, at depths below 15 cm, the majority (90 percent) of residue was confined to the top 15 cm of soil profile. The addition of soil amendments such as lime, organic matter and fertilizer did not appreciably Increase the overall rate of disappearance of the herbicide. The addition of activated coconut charcoal, however, significantly decreased the rate of disappearance of herbicide. Six years after the charcoal plots were established, residues (primarily 2,4,5-T acid) were still present.

Activated carbon adsorption, treatment of wastewater, 125-50,155 Activated coconut charcoal, effect, degradation In soil, 168... 

Charcoal. Activated coconut charcoal has gained the status as the almost universal solid sorbent. Petroleum-based charcoal is less active, but is also widely used. Charcoal is a very effective sorbent and is generally used for collection of nonpolar organic solvent vapors. It also collects polar organics, but they frequently cannot be recovered. However, many organic substances that are reactive, polar, or oxygenated (e.g., chloroprene, acetic acid, and acetone) have been successfully collected and recovered from charcoal. Substances for which charcoal tube methods have been validated are listed in Table II. 

An earlier study at SRI concluded that diphenyl could not be collected on activated coconut charcoal because recovery was poor. The recovery of diphenyl from coconut charcoal is given below. 

The reaction tubes contained 123 parts by weight of activated coconut charcoal, 10-12 mesh, per 100 parts of aluminum chloride. 

Activated coconut charcoal 120 >35 silver to black (pvTOphoricl... 

Air Collect on activated coconut shell charcoal in glass tube desorb with carbon disulfide GC/FID 0.01 mg/sample 98 NIOSH 1994... 

The same author (25) has shown that sulfur is bound to carbon blacks by the action of carbon disulfide at 150°. In the presence of hydrogen sulfide, less carbon disulfide will react with activated carbon (129). The interaction of carbon disulfide and sulfur with coconut charcoal was studied by Sykes and White (130) at low pressures in the temperature... 

The report (5) on the study recommended that a less active charcoal be tested. A literature survey did not yield any conclusive evidence for successful collection by recovery from alternative sorbents. On the basis of the little information available, we selected petroleum charcoal and three porous polymers to test (petroleum charcoal is less active than coconut charcoal). All the porous polymers were based on aromatic monomers, and they should be good collectors for nonpolar aromatics. Aliquots of 113 pg diphenyl were spiked onto these sorbents, and the samples were desorbed with various solvents. The results are given below. 

By defined heating of the second stage, each temperature between 4 K and 100 K can be adjusted. The reference cryosorption material is a coconut-shell-based, highly activated granular charcoal (CHEMVIRON CARBON, type SC-II, US mesh size 12x30), with the sample masses being about 2.5 g. 

Isotherms for the sorption of phosgene by an activated coconut shell charcoal [ia74]. 

POUNDS OF 50-MIN ACTIVATED COCONUT SHELL CHARCOAL REQUIRED PER YEAR0 ... 

The filters are rated for emergency operation at 200 F and a relative humidity of 100 per cent for a period of two hours without loss or decrease in filtering efficiency. The halogen removal filter consists of filters whose filter media is a bed of activated coconut shdl charcoal one inch in depth. 

Actived carbon and graphitized sorbents Coconut charcoal 900 Strong Very volatile compounds Used in series after silica gel Hydrophobic Trap CO2, which can interfere in earlyeluting compounds in GC-MS... 

The capacity of activated coconut-shell charcoal for several common VOCs is indicated by the data of Table 12-28. The values given, which are based on the data of Lamb and Coolidge (1920), do not represent complete equilibrium, but are very close to it for the conditions 0°C (32°F) and 10 mm Hg pressure of solvent vapor over the carbon. More detailed data for one of the solvents (benzene) are presented in Figure 12-40 to illustrate the typical effects of the partial pressure of the solvent and the temperature on the quantity adsorbed. The two upper curves represent adsorber operating cmiditions and the two lower curves represent conditions during regeneration. Adsorption isotherms for other VOCs have generally similar shapes as discussed in the previous section entitled Properties of Gas-Adsorption Carbons. ... 

Carbon Capacity and Integral Heats of Adsorption for Organic Compounds on Activated Coconut-shell Charcoal... 

Figure 12-40. Equilibrium capacity of activated coconut-shell charcoal for benzene. Gas volume measured in ml at standard conditions (0°C, 760 mm Hg) charcoal outgassed at 550 C before tests. Data of Coolidge (1924)...

Figure 12-53. Corrugated bed-type activated charcoal air-purification cell. This unit contains 35 ib of 50-min. activated coconut-shell charcoal and handles 1,000 cfm of air with a pressure drop of 0.25 in. of water. Courtesy of Bamebey Sutcliffe Corp.

Typical yearly requirements in pounds of 50-min. activated coconut-shell charcoal for various occupancies have been given as follows (ASHRAR, 1970) ... 

Capacity of SO-min. Activated Coconut-shell Charcoal for Vapors... 

Activated carbon or activated charcoal Carbon in the form of charcoal granules, which has an affinity to adsorb many gases and vapors and, in so doing, removes odors. It is manufactured by exposing coal, coconut shells, or peat to steam at 800 to 900 C. 

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