EFFECTS OF WASH WATER QUALITY ON THE PHYSICAL PROPERTIES OF THREE PAPERS
J. Nelson, A. King, N. Indictor, & D. Cabelli
DATA OBSERVED INDICATE that the three waters used had different effects on the papers tested. Within the sensitivity of the water testing kits used in this study, no difference in composition is perceptible between the deionized and distilled waters. However, the short-channel single distillation procedure used would not be expected to purify the water as well as the deionization procedure; the distilled water would be expected to contain more inorganic contaminants. This is suggested to be the case by the slightly alkaline pH of the nitrogen-stabilized distilled water, and by the effect of the distilled water wash on the newsprint samples.
As noted previously, in the Tang and Jones study there was a correlation between the purity and pH of the wash water and its effect on the aging characteristics of the samples, with samples washed in the more pure, more acidic waters performing less well in accelerated aging tests than both unwashed controls and samples washed in more alkaline waters. Tang and Jones suggest this results from the loss of calcium due to the aggressiveness or increased solvent power of the ion-poor pure waters,29 while others have suggested that the acidity of the purified waters used in that study might have been a factor.30
In the present study, the pH of the deionized water and of the New York City tap water were comparable, and the more pure deionized water wash was deleterious to some of the papers, while the less pure New York City tap water wash was not, supporting the interpretation of Tang and Jones. On the other hand, the purity of the deionized and distilled waters used in this study were comparable, and the lower pH deionized water wash was deleterious to some of the papers, while the higher pH distilled water wash was not, supporting the contention that it is the acidity of the wash water, not its purity, that is critical. Clearly, more practical investigation is needed to illuminate the undoubtedly complex relation between the characteristics of the waters and papers and the effects of washing.