Heat capacity, of adsorbate

For a system with n components (including nonad-sorbable inert species) there are n — 1 differential mass balance equations of type (17) and n — 1 rate equations [Eq. (18)]. The solution to this set of equations is a set of n — 1 concentration fronts or mass transfer zones separated by plateau regions and with each mass transfer zone propagating through the column at its characteristic velocity as determined by the equilibrium relationship. In addition, if the system is nonisothermal, there will be the differential column heat balance and the particle heat balance equations, which are coupled to the adsorption rate equation through the temperature dependence of the rate and equilibrium constants. The solution for a nonisothermal system will therefore contain an additional mass transfer zone traveling with the characteristic velocity of the temperature front, which is determined by the heat capacities of adsorbent and fluid and the heat of adsorption. A nonisothermal or adiabatic system with n components will therefore have n transitions or mass transfer zones and as such can be considered formally similar to an (n + 1)-component isothermal system. 

In some respects, adiabatic calorimetry provides information which is complementary to that provided by heat-flow calorimetry. The latter allows a study to be made of the full composition range at constant temperature, whereas the adiabatic calorimetry study is carried out over the prescribed range of temperature with a constant amount of adsorptive in the adsorption cell (of course, this does not mean that a constant amount is adsorbed). Adiabatic calorimetry allows direct measurements of the heat capacities of adsorbed films, although they are difficult to make accurately... 

Heat capacity of adsorbed water between that of ice and liquid ... 

External surface area/volume ratio for adsorbent particle Sorbate concentration in fluid phase Initial steady value of c Heat capacity of adsorbent Diffusivity... 

DEPENDENCE OF HEAT CAPACITY OF ADSORBATE ON SURFACE COVERAGE ON THE BASIS OF B.E.T. THEORY ASSUMPTIONS. BEREZIN G I KISELEV A V... 

Cp concentration in exit from packed bed before breakthrough Cres fluid phase concentration in equilibrium with residual loading Ca specific heat capacity of adsorbent particle... 

Solution calorimetry covers the measurement of the energy changes that occur when a compound or a mixture (solid, liquid or gas) is mixed, dissolved or adsorbed in a solvent or a solution. In addition it includes the measurement of the heat capacity of the resultant solution. Solution calorimeters are usually subdivided by the method in which the components are mixed, namely, batch, titration and flow. 

The various terms may now be interpreted as follows T(3Ss/3T)P r CP r is simply the heat capacity of the adsorbate at constant pressure and surface occupancy V - ns/As. The second term is the mechanical work involved in the expansion of Vs on heating here one may introduce a coefficient of expansion ap rVs (3V/3T)pr. For the third term we avail ourselves of the Maxwell relation in the series (5.2.VIII) of Table 5.2.1 T(3Ss/3P)t r — — T(3Vs/3T)p r — — TVsaP r once more this relates to mechanical work associated with an alteration of volume directly caused by pressure changes. The fourth term is related to the contraction of the adsorbate resulting from an increase in pressure this involves the compressibility / T rVs - — (3Vs/3P)t r. For a reformulation of the sixth term we introduce the Maxwell relation from Table 5.2.1, Section VIII T(dSs/dAs)T P>ris - T(d /3T)P r, relating to the temperature... 

All biological transformations are affected by temperature. Generally, as the temperature increases, biological activity tends to increase up to a temperature where enzyme denaturation occurs. The presence of oil should increase soil temperature, particularly at the surface. The darker color increases the heat capacity by adsorbing more radiation. The optimal temperature for biodegradation to occur ranges from 18 C to 30 C. Minimum rates would be expected at 5 C or lower (Frankenberger 1992). 

There have been published numerous papers reporting the measurements of the heat capacity of water adsorbed on oxide surfaces. The likely important effect of the surface heterogeneity on the behaviour of heat capacity data has never been considered yet in the accompanying theoretical interpretations. It may only surprise us, because in the case of other adsorption systems such studies have already been published, demonstrating the crucial role of surface heterogeneity. 

Recently, the measurements of the heat capacity of the adsorbed water have become very popular, but again, as a rule, they are rarely accompanied by adsorption isotherm measurements. 

Three-way catalyses (TWC) require a minimum temperature of approx. 3500C for proper catalytic combustion. Due to the heat capacity of the exhaust system it takes about 1 min after engine start until this temperature level is reached if the catalyst is only heated by the exhaust gas. The amount of toxics produced during this cold-start period presents a considerable fraction of the total amount during one test cycle [1]. Due to more stringent legal purification requirements several concepts were developed to reduce the catalyst heat up time. Presently the main approaches to lower the cold-start emissions are the use of an electrically heated catalyst (EHC) [2], a burner heated catalyst (BHC) [3, 4] and hydrocarbon adsorber systems [5, 61. 

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