The Reaction of Alum with Cation Exchange Cellulose.

摘要

In a previous report the reaction of papermaker's alum (Al2(SO4)3 x 18 H2O) with various paper pulps,as revealed by pH measurements,was described. The purpose of the work reported here was to further investigate the cationic exchange reaction of carboxyl groups,and factors that might influence it,by determining the changes in the composition of the solution resulting from reaction of alum with a cation exchange cellulose. To simplify the study,cation exchange cellulose in the calcium form (CECCa) was used in the present work. This material appears to react with alum in the same way as paper pulps. It is concluded from the observations that acid may be generated in paper in two ways: (1) from the aluminum cellulose carboxylate by an unknown mechanism and (2) from the hydrolysis of aluminum sulfate to form sulfuric acid. Differential thermal analysis on CECCa residues and a determination of the composition of the ash of the residues also were made. The significance of the findings are discussed.