Determination of carbon and hydrogen in bone black and other chars

Abstract

The carbon and hydrogen contents of samples of bone chars, charcoals, and vegetable carbons are determined by combustion in oxygen, the resultant carbon dioxide and water being weighed. The procedure for the handling of such highly adsorptive substances is set forth with a description of the necessary apparatus.A simple procedure is adopted to bring each sample for analysis to a constant weight . This consists in exposure of the sample to air saturated with water in an exsiccator for 18 hours, and subsequent heating in a helium atmosphere at 105 0 C for 18 hours. In the determination of the carbon, corrections are made for the carbonate remaining in the ash from t he combustion and for the carbonate a nd the adsorbed carbon dioxide contained in the original sample. The results are tabulated to give these separate contributions to the total carbon. A comparison is made with results for the same materials obtained by the determination of the loss upon ignition of the acid-washed residue of each sample.

Surface available to nitrogen on bone black and other carbonaceous adsorbents

“…In this case eq 1 reduces to eq 3. For values of n as large as 4 or 5, which is the case for bone chars, and for values of x up t o 0.25, eq 3 becomes a good approximation to eq 1. Hence to use this approximation, one plots the experimental isotherm in the low-pressure region with pIV(po-p) as ordinate and x as abscissa, according to the second formulation of eq 3, and from the intercept of the straight line, equal to l /vmc, and its slope, equal to (c-l) /vmc, it is possible to evaluate c and Vm • In applying these equations to the bone-char data, such linear curves are obtained, as may be seen in figure 10. The data used are the same as those given in the isotherms of figure 4. There is an alternative method of evaluating Vm and c, which may be used for bone chars and which must be used in the case of decoloriz- ing carbons other than bone char.…”

“…PROCEDURE The weight of the sample of adsorbent varied between 0.25 and 1.0 g. Except for samples 19 and 20, which are powdered materials, the particle sizes were between 35 and 80 mesh. The preparation of these samples and the analysis for carbon and hydrogen have been described [10]. 474862-42-2 The samples of adsorbents contained in weighing tubes were dried in an air oven at 130 0 0 for about 20 hours and were cooled in a desiccator.…”

Note on the macroanalysis of carbon and hydrogen by combustion

“…During the past 15 years, several investigations at the National Bureau of Standards have involved precise analyses of carbon and hydrogen [1,2,3,4,5,6]. 1 Each of these investigations incorporated in its apparatus such prior improvements as were appropriate and made some new contributions to the problem.…”