Sorption isotherms on liquid-coated absorbents. Acetone on diatomaceous earth supports coated with tri-o-tolyl phosphate and squalane

Abstract

the magnesium with an excess of this reagent equivalent to 0.1Mfree TTA.In all cases the recovery of these two radionuclides, which were present in millicurie amounts, was found to be higher than 99.9% and their radiochemical purity was virtually 100%.The addition of concentrated hydrochloric acid to the uranium fission product solution and the subsequent reduction of the volume of the solution by evaporation as described in the working procedure, ensures that only less than 0.03z of the total niobium-95 activity is contained in the cesium eluate.The water wash following the removal of TTA with pyridine (see working procedure) is necessary because otherwise the 6N hydrochloric acid, which is subsequently used to elute the cesium, would exothermically react with pyridine and form air bubbles in the resin bed.Strong interference in the separation of cesium-1 37 is caused by the presence of fluoride ion.A coadsorption of bismuth from 0.1M TTA-pyridine solution (see Table I) can be prevented by the addition of a small amount of hydroiodic acid-e.g., 0.1 ml of the concentrated acid in 10 ml of the feed solution.It is expected that the separation procedure described in this paper is also applicable to the isolation of larger quantities of alkali metals from other materials such as trace impurities contained in alkali metal reactor coolants, soils, rocks, and organic matter. Because, however, macro amounts of the chlorides and other salts of sodium, potassium, alkaline earths, and other elements show a limited solubility in the TTApyridine media-e.g., only 0.07 mg of sodium chloride is soluble in 1 ml of 0.1M TTA-pyridine-a modified working procedure has to be employed. This consists of adsorbing the alkali metals on Dowex 50 from a 0.1M TTA solution which is 50 vol % in pyridine and 50 vol z in water. Under these conditions the solubility of sodium chloride is 75 mg NaCl/ml of this mixture. If more sodium chloride is present, two phases are formed: an upper phase consisting mostly of pyridine in which TTA is dissolved, and a lower phase mainly consisting of water saturated with sodium chloride plus undissolved crystals of this compound.Acetone static sorption isotherms were determined on three series of liquid-coated diatomaceous earth supports. The amounts sorbed by Chromosorb P and W coated with increasing percentages of tri-o-tolyl phosphate (TOTP) were equal to the sum of: the amount sorbed by the surface modified by the immediate'covering layer of TOTP molecules, and the amount sorbed by the remainder of the TOTP. The first (about 0.3% w/w) depended upon its own isotherm and was independent of the total amount of TOTP. The second depended upon the amount of excess TOTP and the isotherm for the bulk TOTP liquid. The squalane-coated Chromosorb P series showed that the surface of Chromosorb P was only slightly modified by squalane with respect to acetone, and the amount sorbed up to 2% squalane was essentially the same as that for the uncoated Chromosorb P.

Peak distortion in chromatography. Part 1: Concentration‐dependent behavior

“…Alumina can be modified with controlled amounts of sodium iodide or hydroxide to give linear isotherms [4A. The addition of small amounts of polyethylene glycol to diatomaceous earth supports greatly reduces surface activity [48]. Both diatomaceous earth and silica gel supports are often silanized to eliminate, as far as possible, free silanol groups which otherwise hydrogenbond to polar solutes.…”

Gas chromatography

“…A FORTRAN II program for use with the IBM 7090 computer for surface area measurements was reported (213). Adsorption isotherms were determined for water, acetone, and benzene on modified glass surfaces (204); acetone on liquid-coated diatomaceous earth supports (688,684)', benzene and hexane mixtures on silica gel (609); and water and methanol on several types of polyamide textile fibers (179). Activity coefficients are reported for C4 to C8 hydrocarbons in higher molecular weight hydrocarbons (118,187,288,734) and in binary mixtures of hydrocarbons (623); C1-C4 hydrocarbons in binary mixtures of ß,/3 '-oxydipropionitrile and dibutyl maleate (560); paraffins, aromatics, and halogenated aromatics in Carbowax 400 (52); and fluorinated benzenes in noctadecane in a rigorous study (136).…”