The Effect of Hemicellulose on Water Permeability Passing through Bleached Wood pulp Bed

Abstract

A study on the water permeability of bleached wood pulp and Hemicellulose-adsorbed filter paper pulp beds was carried out.
The characteristic flow of water passing through the beds of holocellulose pulp and bleached kraft pulp, prepared from daglassfir or eucalyptus chip, was observed. The volume of hemicellulose-rich holocellulose pulp bed during permeability test was smaller than that of hemicellulose-poor bleached kraft pulp bed, whereas the water retention value of the former was larger than that of the latter.
Hemicellulose was isolated from holocellulose with 5% KOH solution and 10% KOH·3% sodium borate mixture. The permeability of a dilute hemicellulose solution passing through filter paper pulp bed was proved to be un-explainable with Darcy's law.
The changes in viscosity, transmitance or specific rotation of 1% hemicellulose solution and in absorption of hemicellulose-acridine orange system in the range of 2°C to 90°C were sigmoidal, and were remarkable. The results indicate that the helix-randam coil transition of hemicellulose molecule in water occurs by heating treatment.
When the change of the permeability of hemicellulose solution passing through filter paper pulp bed by heating was compared with that of the comformation of hemicellulose, it is assumed that the water permeability of wood pulp bed increases remarkably with the transition of ordered structure of hemicellulose in the pulp to randam coil one.