Porous carbon

Different types of activated carbon are among the most suitable materials for this purpose. For this reason specialists, involved in development of active materials for EC try to increase carbon s specific surface as much as possible and to optimize the internal structure of the carbon porous structure. 

Keywords Sorption Activated carbon Porous carbon surfaces... 

Mercury has been removed from contaminated brine solutions by means of a reticulated vitreous carbon porous electrode. A reduction factor as large as 5000 was obtained in a single pass. It was shown that the concentration ratio can be represented by the following equation ... 

In the case of the direct electrochemical approach, while the electrolysis conditions are less severe, the selection of the appropriate electrode material is still very important, and further reading on the use of stainless steel [93], platinum [94], graphite [95], doped Sn02 [92], doped Pb02 [86, 87, 96], and so on, is suggested. The economic viability of the electrochemical treatment approach is influenced in no small way by the cost and lifetime of the anode material this can easily make or break the field implementation of the process. Some authors have used high-surface area, porous anodes for cyanide treatment in order to combat the problems of mass-transport limitations so evident at cyanide concentrations below 100 ppm [88]. That system consists of a reticulated vitreous carbon porous anode that was activated for cyanide oxidation by the deposition of some copper oxide. The process looks very promising at the laboratory scale,... 

Support - porous alumina - porous carbon - porous metal plate, disc, tube, monolith plate, tube, hollow fibre woven structures, disc, tube... 

The series of 10 chapters that constitute Part 3 of the book deals mainly with the use of adsorption as a means of characterizing carbons. Thus, the first three chapters in this section complement each other in the use of gas-solid or liquid-solid adsorption to characterize the porous texture and/or the surface chemistry of carbons. Porous texture characterization based on gas adsorption is addressed in Chapter 11 in a very comprehensive manner and includes a description of a number of classical and advanced tools (e.g., density functional theory and Monte Carlo simulations) for the characterization of porosity in carbons. Chapter 12 illustrates the use of adsorption at the liquid-solid interface as a means to characterize both pore texture and surface chemistry. The authon propose these methods (calorimetry, adsorption from solution) to characterize carbons for use in such processes as liquid purification or liquid-solid heterogeneous catalysis, for example. Next, the surface chemical characterization of carbons is comprehensively treated in Chapter 13, which discusses topics such as hydrophilicity and functional groups in carbon as well as the amphoteric characteristics and electrokinetic phenomena on carbon surfaces. 

Surface area of the porous media has a remarkable effect on surfactant adsorption. Liu (2007) measured surfactant adsorption in three rock samples of the same carbonate porous medium but with different surface areas. He used a TC blend surfactant—1 1 mixture by weight of dodecyl 3 ethoxylated sulfate and iso-tridecyl 4 propoxylated sulfate from Stepan. He found that the adsorptions of the TC blend on the three samples were close to each other if the adsorption was calculated by using surfactant adsorption amount per porous media surface area, as shown in Figure 7.43. However, if the adsorption was... 

Including sintered metal, porous carbon, porous ceramic, formed plastics... 

Parameter Non-porous calcium carbonate Porous calcium carbonate ... 

A wide variety of sorbents have been evaluated which include activated charcoal and synthetic carbons porous polymers such as Tenax, Chromosorb series, Porapak series and XAD series liquid phase coated GC packings and bonded GC packings. Although a wide variety of sorbents have been reported in the literature, the four listed below can be used to cover almost the entire range of compounds. 

A whole series of methods has been developed for the investigation of porous solids such as activated carbons, porous glasses, silica gels, and zeolites. Together with some new suggestions, they aU have been applied to the characterization of the porosity of polymeric adsorbents. We will briefly review these methods related to the porosity parameters and emphasize the problems that may arise on their application to polymers, when the specific properties of the polymeric materials are not taken into account. 

Aroutiounian, V. M., Martirosyan, Kh. and Soukiassian, P. Low reflectance of diamond-like carbon/porous silicon double layer antireflection coating for sihcon solar cells , (2004) J. Phys. DiAppl. Phys. 37, L25-L28. 

Bjourkvist, M., Salonen, X,Tuura,T.JalkanenTero, and LehtoVesa-Pekka. Detecting amine vapours with thermally carbonized porous silicon gas sensor , (2009) Phys. Stat. Solidi C. 6,1769-72. 

Figure 3. SEM micrograph of the carbonized and pulverized PAA after Pd deposition. Inset SEM micrograph of PAA prepared in 0.3 M oxalic acid at 60 V. Reprinted from Zhenyou Wang, Fengping Hu and Pei Kang Shen, Carbonized porous anodic alumina as electrocatalyst support for alcohol oxidation, Electrochemistry Communications, 8 (2006) 1764-68, Copyright (2006) with permission from Elsevier.

To further improve the mechanical and electrical stability of silicon-based anodes, a hierarchical bottom-up approach (Fig. 15.12) was successfully utilized to develop a three-dimensional nanostructured silicon/carbon porous composite [89]. The existence of pores in the composite granules provides sufficient space to accommodate silicon expansion during lithium insertion. CVD deposition of silicon clusters (Fig. 15.12b) avoids formation of SiO thus reducing the first cycle, irreversible capacity. A high specific capacity of 1,950 mAh/g (C/20 rate) based on the total weight of the silicon/carbon composite was reported. In addition, the composite anodes had negligible capacity fade after 100 cycles at 1C rate and excellent rate capability (870 mAh/g at 8C rate). 

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