Solute exclusion from cellulose in packed columns: experimental investigation and pore volume measurements.
A packed column approach was used in this investigation to determine pore volume and surface area distributions of several celluloses. Specific surface areas for Avicel PH 102, Solka Floc BW 300, and two size fractions of corn cobs that have been pretreated to remove lignin and hemicellulose were measured using this technique. In addition to measuring pore volume and specific surface area, the molecular diameters of several PEGs (polyethylene glycol) were estimated using viscosity measurements. Also, the influence of cellulose particle size, molecular diameter of PEGs, and PEG solution velocity on dispersion and tailing were investigated. Molecular diameter estimates from this investigation were 30%-35% lower than those reported in the literature. This discrepancy is due to earlier investigators using an inappropriate relationship for estimating molecular diameter from viscosity measurements. The precision of the column approach to solute exclusion was higher than that obtained by investigators using a batch approach. Dispersion increased with increasing particle size. Tailing of the elution curve was increased with increasing solute molecular diameter and elution rate. For a cellulase with a molecular diameter of 5.1 nm, estimated specific surface area ranged from 7.2 to 10.5 m(2) g(-1).
Neuman
R P
RP
Department of Agricultural and Biological Engineering, Riley-Robb Hall, Cornell University, Ithaca, New York 14853, USA.
Walker
L P
LP