Interaction Of Wood-Protecting Anions With The Wood Cell Wall
Keywords:
Anion exclusion, arsenate, cell wall, chromate, diffusion, Donnan membrane effect, phosphate, Pinus resinosa, Populus tremuloides, solute free waterAbstract
Under normal treating conditions, anionic components of wood preservatives and fire retardants, such as arsenates and phosphates, equilibrate at much lower concentrations in the cell-wall bound water than in the free solution in the cell lumens. A degree of anion exclusion is expected in wood due to the Donnan membrane effect. Fixed anions in the wood cell wall are not free to diffuse into the lumens, resulting in limited migration of the mobile anions into the cell wall. The observed exclusion, measured as "solute free water" (δ), decreases with increasing solute concentration, as expected from Donnan exclusion effects. However, the expected pH dependence (increased exclusion with increased pH) is not observed in ammoniacal solutions. In fact, there is an apparent anomalous effect of high cell-wall penetration or reaction with basic solutions containing ammonium hydroxide. Dichromate solutions are more or less depleted from the free lumen solution, depending on the initial pH of the solution as the hexavalent chromium is reduced and fixed to the cell-wall material.References
Aggebrandt, L. G., and O. Samuelson. 1964. Penetration of water-soluble polymers into cellulose fibers. J. Appl. Polymer Sci. 8:2801-2812.nAhlgren, P. A., J. R. Wood, and D. A. I. Goring. 1972. The fiber saturation point of various morphological subdivisions of Douglas-fir and aspen wood. Wood Sci. Technol. 6:81-84.nBriggs, G. E., A. B. Hope, and R. N. Robertson. 1961. Electrolytes and plant cells. Blackwell Scientific Publications. Oxford, England. 217 pp.nCooper, P. A. 1991a. Cation exchange adsorption of copper on wood. Wood Protection 1(1):8-13.nCooper, P. A. 1991b. Diffusion and mierodisitribution of wood protecting chemicals in the wood cell wall. Ph.D. dissertation, Faculty of Forestry. University of Toronto Toronto, Ontario, Canada.nCooper, P. A., and R. Churma. 1990. Estimating diffusion puth length in treated wood. Forest Prod. J. 40(11/12):61-63.nCooper, P. A., and A. Holtforstkr. 1991. Effects of delayed drying on performance of fire retardant treated wood. Proceedings of the International Symposium on Chemical Modification of Wood (Kyoto, Japan. May 17-18, 1991):184-189.nCooper, P. A., and Y. T. Ung. 1992. Accelerated fixation of CCA-treated poles. Forest Prod. J. 42(9):27-32.nDahlgren, S.-E., and W. H. Hartford. 1972. Kinetics and mechanism of fixation of Cu-Cr-As wood preservatives. 1. pH behaviour and general aspects on flxation. Holzforschung. 26(2):62-69.nDafnty, J., and A. B. Hope. 1959. Ionic relations of cells of Chara australis. Austral. J. Biol. Sci. 12(4):395-408.nFarrar, J., and S. M. Neale. 1952. The distribution of ions between cellulose and solutions of electrolyte. J. Colloid Sci. 7:186-195.nFeist, W. C., and H. Tarkow. 1967. Polymer exclusion in wood substance—A new procedure for measuring fiber saturation points. Forest Prod. J. 17(10):65-68.nJenny, H. 1966. Pathways of ions from soil into roots according to diffusion models. Plant Soil 25(2):265-289.nKitson, R. E., and M. G. Mellon. 1944. Further studies of the molybdium blue reaction. Ind. Eng. Chem. Anal. Ed. 16(7):466-469.nKunin, R. 1963. Ion exchange resins. John Wiley and Sons. Inc., London, New York. 466 pp.nPu, Q., and K. Sarkanen. 1989. Donnan equilibria in wood-alkali interactions. Part 1. Quantitative determination of carboxyl-, carboxyl ester and phenolic hydroxyl groups. J. Wood Chem. Technol. 9(3):293-312.nPu, Q., and K. Sarkanen. 1991. Donnan equilibria in wood-alkali interactions. Part 2. Effect of polysaccharide ionization at high alkalinities. J. Wood Chem. Technol. 11(1):1-22.nRennie, P. M. S., S. M. Gray, and D. J. Dickinson. 1987. Copper based water-borne preservatives: Copper adsorption in relation to performance against soft rot. International Research Group Wood Preservation. Doc. IRG/WP/3452.nShreve, R. N. 1945. The chemical process industries. Chemical Engineering Series, McGraw-Hill Book Co. Inc., New York, London.nStamm, A. J. 1971. Review of nine methods for determining the fiber saturation points of wood and wood products. Wood Sci. 4(2): 114-128.n
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