Active charcoal filtration

The mobility of very slowly degradable compounds or persistent metabolites present in surface water or bank filtration-enriched ground water is of particular interest for the production of potable water. In common with many other compounds, certain surfactants, and especially their polar metabolites, have the potential to bypass the technical purification units used, which may include flocculation (active charcoal) filtration, ozonation or chlorination, and thus can be found ultimately in drinking water destined for human consumption (see Chapter 6.4). 

The cost of pretreating contaminated groundwater on site, for discharge to a publicly owned treatment works is often the preferred alternative (provided the facility has the capacity and local regulations allow acceptance). Pretreatment is usually required to prevent explosive vapors in the sewers and disruption of the biological treatment at the plant. The most common pretreatment includes phase separation and reduction of dissolved contaminants to an assured safe concentration. At small sites, it is not unusual to use phase separation, air stripping, and activated charcoal filtration prior to discharge to a sanitary sewer. 

Temporary substitution of the liver function using hepa-tocytes (e. g. in haemofiltration systems or bioreactors) is conceivable in acute liver failure, possibly in conjunction with activated charcoal filtration or with plasma separation. The importance lies in bridging the phase of acute liver failure until compensation of the liver function or liver regeneration is achieved. 

Bis(triphenylphosphine)iminium chloride [PPN]C1, which is easily synthesized3 or available commercially (Alfa Products, Danvers, Massachusetts the systematic IUPAC name for this salt is /u-nitrido-bis(triphenylphosphorus)(l+), is purified by dissolution in hot water, addition of activated charcoal, filtration of the solution, and crystallization from the cooling solution. The resulting crystalline [PPN] Cl is filtered and dried under high vacuum overnight. 

Tertiary sewage treatment is essentially a chemical treatment that removes the fine particles, nitrates, and phosphates in wastewater. The basic procedure is adjusted for the specific substance to be removed. Activated charcoal filtration, for example, is used to remove most of the dissolved organic compounds. And alum (Al2(S04)3) is used to precipitate phosphate ions by dissolving and freeing the aluminum cation. 

Users of more than one millicurie of ra-dioiodine per procedure should work in a dry box with activated charcoal filtration in a certified fume hood. If this procedure is followed, the hood need not be reserved exclusively for radioiodine work. 

Indoleacetic acid In a 1-litre flask, fitted with a reflux condenser, place a solution of 35 2 g. of sodium cyanide in 70 ml. of water, then add 25 g. of gramine and 280 ml. of 95 per cent, ethanol. Reflux the mixture (steam bath) for 80 hours. Dilute the cooled reaction mixture with 35 ml. of water, shake with a little activated charcoal (e.g., Norit), filter and concentrate to about 350 ml. imder reduced pressure (water pump) in order to remove most of the alcohol. Cool to about 5°, filter off the solid and wash it with a little cold water keep the filtrate (A). Recrystallise the solid from alcohol-ether to give 5-0 g. of 3-indoleacetamide, m.p. 150-151°. 

Charcoal is generally satisfactorily activated by heating gently to red heat in a crucible or quartz beaker in a muffle furnace, finally allowing to cool under an inert atmosphere in a desiccator. Good commercial activated charcoal is made from wood, e.g. Norit (from Birch wood), Darco and Nuchar. If the cost is important then the cheaper animal charcoal (bone charcoal) can be used. However, this charcoal contains calcium phosphate and other calcium salts and cannot be used with acidic materials. In this case the charcoal is boiled with dilute hydrochloric acid (1 1 by volume) for 2-3h, diluted with distilled water and filtered through a fine grade paper on a Buchner flask, washed with distilled water until the filtrate is almost neutral, and dried first in air then in a vacuum, and activated as above. To improve the porosity, charcoal columns are usually prepared in admixture with diatomaceous earth. 

Glutaraldehyde [111-30-8] M 100.1, b 71 /10mm, as 50% aq soln. Likely impurities are oxidation products - acids, semialdehydes and polymers. It can be purified by repeated washing with activated charcoal (Norit) followed by vacuum filtration, using 15-20g charcoal/KKhnL of glutaraldehyde soln. 

Potassium hydrogen malate [4675-64-3] M 172.2. A saturated aqueous solution at 60° was decolorised with activated charcoal, and filtered. The filtrate was cooled in water-ice bath and the salt was ppted by addition of EtOH. After being crystallised five times from ethanol-water mixtures, it was dried overnight at 130° in zir [Edenand Bales J Res Nat Bur Stand 62 161 1959],... 

Sodium silicate solution [1344-09-8] pKj 9.51, pKj 11.77 (for silicic acid, H4Si04) Purified by contact filtration with activated charcoal. 

Filter aids may be applied in one of two ways. The first method involves the use of a precoat filter aid, which can be applied as a thin layer over the filter before the suspension is pumped to the apparatus. A precoat prevents fine suspension particles from becoming so entangled in the filter medium that its resistance becomes exces-sive. In addition it facilitates the removal of filter cake at the end of the filtration cycle. The second application method involves incorporation of a certain amount of the material with the suspension before introducing it to the filter. The addition of filter aids increases the porosity of the sludge, decreases its compressibility, and reduces the resistance of the cake. In some cases the filter aid displays an adsorption action, which results in particle separation of sizes down to 0.1 /i. The adsorption ability of certain filter aids, such as bleached earth and activated charcoals, is manifest by a decoloring of the suspension s liquid phase. This practice is widely used for treating fats and oils. The properties of these additives are determined by the characteristics... 

Granular media filtration is used for treating aqueous waste streams. The filter media consists of a bed of granular particles (typically sand or sand with anthracite or coal). The anthracite has adsorptive characteristics and hence can be beneficial in removing some biological and chemical contaminants in the wastewater. This material may also be substituted for activated charcoal. 

Activated carbon is also available in special forms such as a cloth and fibres. Activated Charcoal Cloth (ACC) represents a family of activated carbons in cloth form. These products are fundamentally unique in several important ways compared with the traditional forms of activated carbon and with other filtration media that incorporate small particles of activated carbon. Developed in the early 1970 s ACC products are... 

Treatment Systems for Household Water Supplies - Activated Carbon Filtration - 1992 article from the North Dakota State University Extension Service explaining in detail what activated charcoal systems can and cannot do. http //www. ext. nodak.edu/extpubs/h2oqual. 

The mixture was refluxed gently on a steam bath for VA hours. Fifteen minutes after initiating the reaction, the reaction mixture gave a negative ferric chloride test. Most of the ethanol and acetic acid were removed by distillation in vacuo, 300 ml of water and 300 ml of ether were added to the concentrate, and the mixture was shaken. The layers were separated, the aqueous layer extracted with fresh ether, and the combined ether extracts were washed with water, dried over anhydrous sodium sulfate, filtered and evaporated to dryness in vacuo. The residue was crystalli2ed by trituration with ether, and the crystals were collected by filtration, washed with hexane and dried. The mother liquors were concentrated to dryness and dissolved in a minimum amount of acetone, whereupon a second crop was obtained. The two crops were combined, dissolved in ethyl acetate, decolori2ed with activated charcoal, and recovered by concentration. 

The crude iodinated acid was then dissolved in 500 ml of 95% alcohol, 10 g of dimethyl-aminoethanol was added, the solution was decolorized with activated charcoal and filtered at 70°C. After keeping the filtrate for several hours at 5°C, the heavy crystalline precipitate which formed was collected by filtration and washed with acetone. The mother liquors were concentrated to 150 ml and cooled to give a second crop which was further purified by recrystallization from 50 ml of 95% alcohol. In this way a total of 36.0 g of dimethyl-aminoethanol salt of dextro-/3-(3,5-diiodo-4-hydroxy)-o-phenylpropionic acid, MP 151° to 153°C, was obtained. The melting point of the dimethylaminoethanol salt of unresolved /3-(3,5-diiodo-4-hydroxy)-o-phenylpropionic acid was 142° to 144°C. 

A solution comprising 3,24 kg (23.3 mols) of pyridine-2,6-dimethanol in 35 liters of pure pyridine was added to the residue and the mass was heated to 80°C for 2 /a hours. The reaction mass became brown in color. The chlorhydrate of pyridine so formed was cooled and crystallized. The resulting reaction mass was then poured into water. The precipitate obtained was filtered, repeatedly rinsed with water, and dissolved in 400 liters of methanol. The resulting solution was filtered with activated charcoal. From this filtration 50 liters of methanol were distilled at normal pressure and then crystallized. 8.35 kg (15.8 mols) of pyridine-2,6-dimethanol trimethoxybenzoate were obtained, which represented a yield of 68%. 

A mixture of 20 g (0.1 mol) of 1 -azaphenothiazine, 4.3 g (0.11 mol) of sodamide and 300 ml of dry toluene is stirred and refluxed for eight hours. A slow stream of dry nitrogen gas is used to sweep out the ammonia as formed. The mixture is cooled and 110 ml of a 1 M solution of 3-dimethylaminopropyl chloride in toluene is added dropwise, with stirring. Subsequently, the mixture is stirred and refluxed for fifteen hours, cooled, and concentrated in vacuo. The viscous residue is refluxed with 500 ml of chloroform and filtered hot. The chloroform filtrate is treated with activated charcoal and again filtered. The filtrate is concentrated and the residue distilled to give about 19.B g (69% yield) of product, an oil distilling at about 195 C to 19B°C (under 0.5 mm pressure of mercury). 

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