Activated carbon disks

J. Slobodnik, O. Ostezkizan, H. Lingeman and U. A. Th Brinkman, Solid-phase extraction of polar pesticides from environmental water samples on grapliitised carbon and Empore-activated carbon disks and on-line coupling to octadecyl-bonded silica analytical columns , J. Chromatogr. 750 227-238 (1996). 

Activated carbon disks have also been used for the extraction of polar pesticides from environmental water samples. Slobodnik et alP used an Empore activated carbon disk (EACD) and Envi-Carb graphitized carbon black (GCB) and CPP-50 graphitized carbon for the trace enrichment of polar pesticides from water. 

Almansa et al. (2004), using olive stones with solutions of ZnCl2, prepared binderless activated carbon disks by pressure compaction at 130 MPa, at 150 and 300 °C, finally heating to 500 °C, using 19,24,32,38 and 48 wt% of ZnCl2. Volumes of micro- and mesoporosities were obtained from isotherms of N2 at 77 K. Results are in Figures 6.8 and 6.9. The disk 300... 

The choice of solid carriers spans a wide spectrum (Table 1) from materials most suitable for research purposes (sintered glass beads, laterite stone deposited on a gramophone disk) to industrial materials (pumice, activated carbon, etc.). Key properties that affect the performance of the carrier are porosity (from impervious to controlled-size pores), composition (from ceramics to activated carbon), and hydrophilic behavior. It is difficult to perform a direct comparison of different carriers. Colonization and biofilm growth depend strongly on the nature of bacteria and on their intrinsic propensity to adhere on hydrophilic vs. hydrophobic surfaces. 

The preparation of carbon disk-shape UMEs is similar to that of the carbon fibre UME. The only difference is that the active part is sealed on epoxy resin. With this purpose, a micropipette tip (1 mL) is glued to the head-tip of a carbon fibre UME. The carbon fibre is maintained in vertical position with a metal hook and the micropipette tip (1 mL) is filled with epoxy resin. Once the resin is cured, the tip is cross-sectioned with a microtome or a blade. Then, the disk carbon UME is ready. 

Activated carbon, which is a common trapping sorbent for organic species, can also be used for trace metals.1 This material is typically used by passing the samples through a thin layer (50 to 150 mg) of the activated carbon that is supported on a filter disk. It can also be used by shaking 50 to 150 mg of activated carbon in the solution containing the heavy metal, and then filtering the sorbent out of the solution. 

Figure 23.9 Trace analysis of a metal (M) analyte in the presence of surfactants (S) using the vertically active and horizontally passive aligned nanowires. Such adaptive operation leads to opening and closing of the surface to allow measurement and protection of the transducer between measurements. Also shown are the optical images (top view) of the glassy-carbon disk electrode covered with the vertically (left) and horizontally (right) aligned nanowires.47 (Reprinted with permission from R. Laocharoensuk et al.,...

Fritted glass disks and active carbons Compressed Ni turnings, 100 to 500 mesh, 0.1. .. 0.03 (13)... 

The effects of pyrolysis on the electrocatalytic properties of the same three macrocycles dispersed in Vulcan XC-72 for 02 reduction were examined using thin porous electrodes applied to the carbon disk of an RRD E as sembly. Steady state polarization curves obtained at co = 2500 rpminO.l M NaOH and 0.05 M H2S04are shown in Figures 3.70 and 3.71. As is evident from the results presented therein, the activity of H2TMPP in both media (see solid squares) before and after pyrolysis was much lower than that of the metallated counterparts and fairly close to that of... 

ISO 176 [179] consists of two methods for quantitatively determining the loss in mass of a plastic in the presence of activated carbon when it is subjected to given temperature and time conditions. In Method A, the test material is in direct contact with the carbon. This method is particularly suited to materials that must be tested at low temperatures because they flow at higher temperatures. Method B, on the other hand, has the test material placed in a wire cage to prevent direct contact with the carbon. In both methods the standard test piece is a disk 50 mm diameter by I mm thick, although other dimensions are allowed where other factors make this necessary. For Method A, the test pieces are weighed and the thickness recorded before they are placed in a metal container containing a bed of 120 cm of activated carbon. A further 120 cm of carbon is then placed on top of the first test piece, and then the second test piece is placed on this. The process is repeated... 

Cyclic voltammetric studies of these metallodendrimers showed one reversible oxidation wave, characteristic of independent, non-interacting redox centers. Also, the use of these materials for the modification of electrode surfaces was explored [37-39]. The researchers found that platinum, glass, and carbon-disk electrodes modified by electrodeposited films of these dendrimers are extremely durable and reproducible, with no detected loss of electroactivity even after their use in different electrolyte solutions or after standing for long periods in air. Studies on the thermodynamics and kinetics of adsorption of these redox-active dendrimers onto Pt electrodes by means of electrochemical and electrochemical quartz crystal microbalance techniques were conducted. These showed the adsorption processes to be activation-controlled rather than diffusion-controDed, and to be dependent on... 

Figure 5.6 shows a top view of the ring slit on the disk of the pendulum filled with activated carbon Norit R1 Extra powder. Uniform distribution of the powder within the slit is mandatory to get reproducible results of oscillometric measurements. 

All of the catalysts synthesized are listed in Table 2, and the performance in rotating disk electrode (RDE) in acid conditions are depicted in Fig. 6 [65, 67, 70-72]. In RDE tests (RRDE-3A ALS coupled with a Bio-Logic SP-150 multi-potentiostat), a conventional three-electrode electrochemical cell configuration, equipped with a glassy carbon disk working electrode (0.1256 cm geometric area), a Pt helical wire counter electrode, and a saturated calomel (SCE) reference electrode, was used. The activity of a commercial 40 % Pt/C (Hyspec 6000 from Johnson Matthey) catalyst was assessed as well, as reference catalyst toward ORR. 

In Fig. 15, the TG-SC mode was used to visualize the ORR activity of a small array of spatially resolved Pt and Ru spots (size range 200-300 pm) deposited on a glassy carbon disk by means of a micropipette [59]. Higher sample currents indicate higher ORR activity of the underlying region or catalyst spot. Intrinsic differences in the ORR activity of Pt and Ru deposits could be clearly visualized, with Pt... 

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