dc.contributor.author | Odhiambo, Douglas | |
dc.date.accessioned | 2013-09-26T06:01:25Z | |
dc.date.available | 2013-09-26T06:01:25Z | |
dc.date.issued | 1969-11 | |
dc.identifier.citation | Odhiambo,D.,November,1969.Studies in sorption of benzene by Kenya diatomite. | en |
dc.identifier.uri | http://erepository.uonbi.ac.ke:8080/xmlui/handle/123456789/56688 | |
dc.description.abstract | The BET surface area of Kenya diatomite has been determined by
using a gravimetric method. The surface area of the diatomite was
found to be 30.1 m2 g-1 and acid treatment with warm 3N hydrochloric
acid increased the surf'ac e area by 20%. Samples of untreated and
acid treated diatomite were heated in air at 300, 400, 700 and
1000oc. The surface areas of both untreated and acid-treated
samples decreased with increasing temperature of heating to the
same value of 2.2 m2 g-1 when heated to 1000 C.
Benzene adsorption isotherms at 25.00c have been determined
for all samples. Hysteresis occurred in all cases except for
samples heated at 10000c. The untreated diatomite samples exhibit
Low-pressure hysteresis, while the isotherms on acid-treated
samples had reversible portions in the pressure range 0 - 0.37po ,
where Po is the saturation vapour pressure of benzene at 250 C.
The benzene isotherms have also been plotted according to the
BET theory. Good straight lines were obtained. From the BET
plots, surface areas have been estimated using 40 A02 as the area
of cross-section of an adsorbed benzene molecule. Agreement with
nitrogen surface areas was obtained for some samples.
The radii of capillaries have been calculated with the aid
of the Kelvin equation, from both adsorption and desorption
boundary curves of the hysteresis loops. In all cases, it was
found that
ra < rd < 2ra while ( pa /po)2 < pd/po;
where ra and pa are the radius and pressure from the adsorption
branch and rd and Pd are the radius and pressure from the desorption
branch of the hysteresis loops.
Distributions of capillary radii have also been calculated
from desorption scanning curves of the hysteresis loops. Some
regularity in the formation of the capillaries is revealed in the
linear relationship between the radius of the predominant small
capillary and that of the corresponding starting large capillary.
No correction for thickness of the adsorbed film was made in
Calculation of capillary radii, owing to the difficulty of obtaining a
meaningful ‘t' plot for benzene. | |
dc.language.iso | en | en |
dc.publisher | University of Nairobi | en |
dc.title | Studies in sorption of benzene by Kenya diatomite | en |
dc.type | Thesis | en |
local.publisher | College of Biological and Physical Sciences | en |