T H E JOURNAL OF INDUSTRIAL A N D ENGINEERING CHEMISTRY
198
Vol. 14, No. 3
Alleged Adsorption of Alumina from Aluminium Sulfate Solutions by Cellulose’ By Alfred Tingle2 THEE.
B, EDDYCo. LTD., HULL, P. Q,
T
HE work here described was undertaken with the
further in an authoritative manner when the supply of pure object of obtaining some first-hand information as cellulose which has been promised to the Cellulose Section to the extent to which alumina is adsorbed from its of the SOCIETY is available for research purposes. sulfate solution by cellulose in general and paper-making ANALYTICAL MDTHODS pulps in particular. The occurrence of this phenomenon is asserted or assumed by many writers, but the evidence “COMBINED AlzOa”-Either Method A or Method B,7 deon which these assertions are made is seldom cited. scribed previously, was used. Whichever method was chosen Adsqrption of alumina by cellulose is appealed to by as more convenient was adhered to throughout the same Cross and Bevan, for example, as a factor of importance in set of determinations. “TOTAL AlzO,”-The method was that of W. BlumB8 the theory of paper ~ i z i n g . ~The only reference in original “BASIC AlzOs”-When not found by difference betxveen literature which the present writer has been able to find is to the work of Sohwalb and Robsahm4 and of Sutermei~ter.~“total” and “combined” A l 2 0 3 , the Craig-Scott methodg was The phenomena observed by Schwalb and Robsahm were ob- used with a slight modification of no importance. viously not connectod with adsorption at all, but were simple precipitations of alumina by the noncellulose constituents PREPARATION OF STRONGLY BASIC ALUMINIUM. SULFATE SOLUTIONS of the pulp. Sutermeister found much lower figures for the amount of Ala(SO& decomposed, but the origin of the To 300 cc. of a 10 per cent solution of pure Ah(SO&, 100 phenomena observed remains a little obscure. More lately cc. of 4 per cent NaOH solution were added. The resulting Kolthoff using purified filter paper, has concluded that precipitate was well stirred and poured into another 300 cc. positive ions are separated from salts not by cellulose, but of the same Alz(SO& solution. After a few hours the mixby the ash constituents. ture was filtered. The filtrate WRS diluted for use as required, Expts. 2 and 3, described in detail below, show that neither but when so diluted could not be preserved for long without acid-washed filter paper nor well-washed bleached sulfite change. pulp removes any analytically appreciable amount of alumina DESCRIPTION OF EXP~RIMENTS from a basic solution of aluminium sulfate, when brought in EXPT. 1-Approximately 6 g. (dry weight) of well washed and beaten, ordinary contact therewith. Expt. 3 shows that pure filter sulfite spruce pulp, in a 500-cc. graduated flask, were treated with paper does not adsorb alumina from a nonbasic solution of bleached 100 CC. of a basic aluminium sulfate solution. The mixture was agitated, sulfate even when the two are very thoroughly beaten to- diluted t o 500 cc., and filtered. A blank experiment was made a t the same gether, while Expt. 4 shows conditions under which a reten- time by diluting 100 cc. of the same basic sulfate solution t o 500 CC. with tion of alumina may occur. In this case the pulp used had water, and filtering, “Basic AleOt” was determined in 100 cc. of each filtrate, with the folan alkaline reaction. Some precipitation took place (shown by the reduced amount of “total AbO;’), while the still lowing results: PULPPRESENT BLANK greater reduction in the combined alumina present indicated NaOH equivalent to “Basic AlrOs,” CC. 24.1 24.0 the formation of a “basic salt,” but these changes were obTiter. of NaOH 0.27.N 0.27 N Basic A1;Os” in 100 cc. filtrate, grams 0.1140 0.1135 viously due to chemical action, not to adsorption or any related phenomenon, Expt. 5 serves to show that even when EXPT. 2-A filter was prepared by folding together 15 No. 30 Whatman a neutral solution of aluminium sulfate is converted into a 15-cm. filter papers (total weight approx. 20 g.), and 100 cc. of a clear, rather basic one in the presence of a well-washed sulfite pulp, the strong solution of basic aluminium sulfate were poured thereon. Only 55 cc. of filtrate passed through, the remainder being absorbed by the papers. DeCellulose adsorbs no alumina. terminations were made as follows on 50 CC. of the original solution and on Some errors on the subject may well have arisen from the same volume of filtrate: manipulative mistakes. It is sometimes forgotten that diluSolution Passed Original Solution through Filter tion of a basic aluminium sulfate solution will cause the Grams Grams Total All08 0.1287 0.1291 precipitation of alumina, BO that apparent failures to wash “Combined AlzOa” 0.1018 Not determined aluminium salts completely out of cellulose must not be “Basic AlrOs” (by difference) 0.0265 Not determined taken as conclusive evidence of adsorption till all surroundEXPT.3-Twenty-two Whatman No. 44 9-cm. filter papers (approx. ing factors have been very carefully scrutinized. weight 10 9.) were beaten in a ball mill for 2 hrs. with 200 CC. of AID(SOI)~ The present work is not regarded by the author RS justi- solution (containing no “basic AlzOi”) and 400 g. of pebbles. The resulting pulp was pressed and filtered. The total AlzOi found in 100 cc. of the fication for drawing a final conclusion, but as establishing original solution was 0.1620 g.; in 100 cc. of the filtrate, 0.1619 g. A migrounds for remonable doubt as to whether the alleged ad- croscopic examination of the fibers before and after the beating indicated sorption actually takes place. It makes it reasonable for t h a t a considerably increased degree of hydration had been induced during the matter, which has a very practical bearing if the theory the process. EXPT.&About 20 g. of air-dry, bleached sulfite spruce pulp, washed of paper sizing is ever to be put on its feet, to be investigated 1 Presented before the Section of Cellulose Chemistry a t the 62nd Meeting of the American Chemical Society, New York, N. Y., September 6 to 10, 1921. 2 Chemist to the E. B. Eddy Co. Ltd. 8 “Paper Making,” 5th ed., 248. 4 Wochbl. Papierfabr., 43 (1912), 1454. 6 Pulp Paper Mag. Can., 11 (1913),803. $6 Pharm Weekblad., 87 (1920), 1510, 1529.
only by an ordinary mill process, were beaten in a ball mill with 400 cc. of aluminium sulfate solution under the conditions of Expt. 3. The solution was then filtered frbm the pulp. Determinations were made on this filtrate and on the original solution, as follows: 7
8
THIS JOURNAL, 13 (1921), 420. J. Am. Chem. Soc., 88 (1916), 1282. THISJOURNAL, 7 (1915), 1059.
