Activated Carbon Additives

A negative electrode of a 2 V ceU and 12 V lead-acid battery was doped with activated carbon additives. 

It turned out that the negative electrode that contained tens-of-mi-cron-sized carbon particles in the negative active material exhibits a markedly increased high rate partial state of charge duty than a comparative material containing carbon particles with much smaller size of several microns or a material containing no activated carbon. 

The improved performance has been attributed to the optimized negative active material microstructure and the enhanced electrode reaction kinetics by introducing appropriate activated carbon. The beneficial effects can be briefly explained as such (11)  

The activated carbon acts as new porous-skeleton builder to increase the porosity and active surface of the negative active material, and thus facilitates the electrolyte diffusion from surface to inner plate and provides more sites for crys-tallization/dissolution of lead sulfate 

The activated carbon plays the role of an electrolyte supplier to provide sufficient H2SO4 in the inner plate when the diffusion of H2SO4 from plate surface cannot keep pace with the electrode reaction. 

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Catalysts from active carbon additionally activated with cobalt- or iron- phthalocyanines are also studied [7], The results show that at current densities up to 50 mA/cm2, the polarization of the air electrodes with catalyst from active carbon promoted with FePc is lower than that of the electrode with catalyst from active carbon promoted with CoPc. At higher current density the polarization of the electrode with catalyst from active carbon promoted with CoPc is lower, which is probably connected to the lower transport hindrances, due to the more favorable structure of this catalyst. 

Kargi, E., Pamukoglu, M.Y. 2004b. Repeated fed-batch biological treatment of pre-treated landfill leachate by powdered activated carbon addition. Enzyme Microbial Technol 34 422 28. 

Osantowski, R.A. Dempsey, C.R. Dostal, K.A. Enhanced COD removal from pharmaceutical wastewater using powdered activated carbon addition to an activated sludge system. Proceeding of the 35th Industrial Waste Conference, Purdue University, West Lafayette, IN, 1980 719-727. 

The city of Columbus, Ohio, installed a PACT water treatment system for 1.2 million. The system was purchased to remove atrazine (a pesticide) from the water supply. In 1997, Columbus spent 150,000 on powered activated carbon. Additional monitoring costs were estimated to be over 10,000 per year (D19947H, p. 11). 

Human adipose Addition of 13C-labeled standards to tissue followed by extraction with methylene chloride, acid-base washing, solvent exchange, treatment with silica gel impregnated with sulfuric acid, column chromatography using acidic silica gel, neutral alumina, and activated carbon addition of Relabeled standards. HRGC/HRMS (EPA Method 8290) 1 ppt No data EPA 1994c... 

Park, H., Choo, K. H., Lee, C. H. (1999). Flux enhancement with powdered activated carbon addition in the membrane anaerobic bioreactor. Separation Science and Technology, 34(14), 2781-2792. 

Vyrides, I., Stuckey, D. C. (2009). Saline sewage treatment using a submerged anaerobic membrane reactor (SAMBR) effects of activated carbon addition and biogas-sparging... 

The differences between these redox-polymers and the now much discussed "polymeric metals" is the additional property being conductive in the ion-radical state. This is a feature most welcome in the construction of batteries but as such not a necessary requirement. The possibilities offered by the redox polymers were of course realized many years ago and have been described by Cassidy.Batteries in which one or both electrodes were a redox polymer in nature have been patented.Due to the insulating nature of these early redox polymers the electrodes were prepared from a mixture of the finely divided polymer and a conductor such as graphite, metal dust or activated carbon. Additionally or alternatively a redox electrolyte was added to act as the mediator between the insoluble and insulating redox polymer and the metal electrode. Since the oxidized or reduced form of the redox polymer can be regenerated and the process recycled, the resulting unit is a secondary cell. 

The one-carbon addition we used in frames 98 and 101 is all right if we just want to add an activating group to a readily available ketone, but is not otherwise good synthetic practice ... 

Three approaches have been identified that reduce susceptibility of CA resists to airborne contamination. In the first, process engineering changes such as the addition of special activated carbon filters to the environmental chambers surrounding the exposure tools (76,79), overcoating the resist with a soluble protective film to isolate the resist from the environment (77,80,81), or modifications of the process flow to minimize the time interval between exposure and post-exposure bake have been shown to improve CA resist processibibty. 

Chlorine can be removed by either activated carbon adsorption or by reaction with olefins such as ethylene over-activated carbon at temperatures of 30—200°C (44). Addition of Hquid high boiling paraffins can reduce the chlorine content in the HCl gas to less than 0.01% (45). 

Another method employed is the treatment of aqueous solutions of aminophenols with activated carbon (81,82). During this procedure, sodium sulfite, sodium dithionite, or disodium ethylenediaminotetraacetate (82) is added to increase the quaUty and stabiUty of the products and to chelate heavy-metal ions that would catalyze oxidation. Addition of sodium dithionite, hydrazine (82), or sodium hydrosulfite (83) also is recommended during precipitation or crystallization of aminophenols. 

The original hot carbonate process developed by the U.S. Bureau of Mines was found to be corrosive to carbon steel (55). Various additives have been used in order to improve the mass transfer rate as well as to inhibit corrosion. Vetrocoke, Carsol, Catacarb, Benfteld, and Lurgi processes are all activated carbonate processes. Improvements in additives and optimization of operation have made activated carbonate processes competitive with activated MDEA and nonaqueous solvent based systems. Typical energy requirements are given in Table 9. 

The sulfur then reacts to form the polysulfide according to equation 12. The key is the use of a catalyst to promote the formation of elemental sulfur. Commercial systems are based on the use of air with an activated carbon catalyst (41). The need for additional sulfur is eliminated, but the sulfur level is... 

Reactions of Vinyl Ethers. Vinyl ethers undergo the typical reactions of activated carbon—carbon double bonds. A key reaction of VEs is acid-catalyzed hydrolysis to the corresponding alcohol and acetaldehyde, ie, addition of water followed by decomposition of the hemiacetal. Eor example, for MVE, the reaction is... 

In addition to surface area, pore size distribution, and surface chemistry, other important properties of commercial activated carbon products include pore volume, particle size distribution, apparent or bulk density, particle density, abrasion resistance, hardness, and ash content. The range of these and other properties is illustrated in Table 1 together with specific values for selected commercial grades of powdered, granular, and shaped activated carbon products used in Hquid- or gas-phase appHcations (19). 

Potable Water Treatment. Treatment of drinking water accounts for about 24% of the total activated carbon used in Hquid-phase apphcations (74). Rivers, lakes, and groundwater from weUs, the most common drinking water sources, are often contaminated with bacteria, vimses, natural vegetation decay products, halogenated materials, and volatile organic compounds. Normal water disinfection and filtration treatment steps remove or destroy the bulk of these materials (75). However, treatment by activated carbon is an important additional step in many plants to remove toxic and other organic materials (76—78) for safety and palatability. 

Catalysis. Catalytic properties of the activated carbon surface are useful in both inorganic and organic synthesis. For example, the fumigant sulfuryl fluoride is made by reaction of sulfur dioxide with hydrogen fluoride and fluorine over activated carbon (114). Activated carbon also catalyzes the addition of halogens across a carbon—carbon double bond in the production of a variety of organic haUdes (85) and is used in the production of phosgene... 

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