Kinetic Model of CCA Fixation on Wood. Part III. Model Validation

Authors

  • Feroz K.M. Kazi
  • Paul A. Cooper
  • Tony Y. Ung

Keywords:

Chromated copper arsenate (CCA-C), fixation, <i>Pinus resinosa</i> Ait., model, initial reaction, main reaction, kinetics, validation

Abstract

In previous studies, models were developed for the initial and main fixation reactions of chromated copper arsenate (CCA-C) on red pine wood as a function of time and isothermal wood temperature conditions following treatment with 1% CCA-C. In this study, these models are used to predict the amount of fixation over sequential short non-isothermal intervals as a way of predicting time to total fixation under variable temperature conditions. The rate of fixation of CCA-C treated red pine pole sections could generally be accurately predicted, using these models, from thermocouple temperature readings in the pole surface, even under a highly variable temperature fixation regime. However, variations in fixation rate were observed even within a single pole, associated with density differences at the butts and tops of the poles. This confirms that fixation time estimates are very sensitive to the model parameters and suggests that the model may not accurately predict fixation rates over a wide range of material sources.

References

Alexander. D.L., and P.A. Cooper. 1993. Effects of temperature and humidity on CCA-C fixation in pine sap-wood. Wood Protection 2(2): 1-7.nAnderson, D.G. 1989. The accelerated fixation of chromated copper preservative treated wood. Proc. Can. Wood Preserv. Assoc. 10:75-111.nAyres. F. Jr. 1964. Theory and problems of differential and integral calculus. 2nd ed. Schaum Publishing Co., New York. NY. P. 254.nCoggins. C. and P. Hiscocks. 1978. Chromium on the surface of CCA treated wood. Int. Res. Group on Wood Preserv. Doc. No. IRG/WP/386.nCooper. P. A., and Y. T. Ung. 1989. Moderate temperature fixation of CCA-C treated poles. Int. Res. Group on Wood Preserv. Doc. No. IRG/WP/3522.nCooper. P. A., and Y. T. Ung. 1993. A simple leaching test for quantitative determination of CCA fixation. Forest Prod. J. 43(5): 19-20.nCooper. P. A., D. L. Alexander, and Y. T. Ung. 1993. What is chemical fixation. Pages 7-13 in J. Lang, ed. Chromium-containing waterborne wood preservatives: Fixation and environmental issues. Forest Products Society. Madison WI.nDahlren, S. E. 1974. Kinetics and mechanism of fixation of Cu-Cr-As wood preservatives. Part IV. Conversion reactions during storage. Holzforschung 28(2):58-61.nDahlren, S. E. 1975. Kinetics and mechanism of fixation of Cu-Cr-As wood preservatives. Part VI. The length of the primary precipitation fixation period. Holzoforsehung 29(4): 130-133.nDahlren, S. E., and W. H. Hartford. 1972a. Kinetics and mechanism of fixation of Cu-Cr-As wood preservatives. Part I. pH behaviour and general aspects of fixation. Holzforschung 26(2):62-69.nDahlren, S. E., and W. H. Hartford. 1972b. Kinetics and mechanism of fixation of Cu-Cr-As wood preservatives. Part II. Fixation of Boliden K33. Holzforschung 26(3): 105-113.nDahlren, S. E., and W. H. Hartford. 1972c. Kinetics and mechanism of fixation of Cu-Cr-As wood preservatives. Part III. Fixation of Tanalith C and comparison of different preservatives. Holzforschung 26(4):142-149.nFoster, D. O. 1988. Proposed A.W.P.A. method for determination of the presence of hexavalent chromium in treated wood. Proc. Can. Wood Preserv. Assoc. 9:29.nKazi, K. M. F., and P. A. Cooper. 2000. Kinetic model of CCA fixation on wood. Part 1. The initial reaction zone. Wood Fiber Sci. 32(3):354-361.nKazi, K. M. F., P. A. Cooper., and J. Chen. 2000. Kinetic model of CCA fixation on wood. Part II. The main reaction zone. Wood Fiber Sci. 32(4):442-449.nMcNamara, W. S. 1989. CCA fixation experiments—Part 1. Int. Res. Group on Wood Preserv. Doc. No. IRG/WP/3504.nOsborne, P. D. 1991. Effect of high CCA retentions on the percent fixation and fixation rate. Proc. Am. Wood Preserv. Assoc. Vol. 87. Report of Subcommittee T-2.nPanshin, A. J., and C. DeZeeuw. 1980. Textbook of wood technology. Vol. I, 4th ed. McGraw-Hill, New York, NY.nPizzi, A. 1982. The chemistry and kinetic behaviour of Cu-Cr-As/B wood preservatives. Part IV. Fixation of CCA to wood. J. Polym. Sci. Chem. Ed. 20:739-764.nWilson, A. 1971. The effects of temperature, solution strength and timber species on the rate of fixation of a Copper-Chrome-Arsenate wood preservative. J. Inst. Wood Sci. 5:36-40.n

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Published

2007-06-05

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Research Contributions