Theses and Dissertations

Issuing Body

Mississippi State University

Advisor

Borazjani, Hamid.

Committee Member

Nicholas, Darrel D.

Committee Member

Prewitt, M. Lynn

Committee Member

Kitchens, Shane

Committee Member

Diehl, Susan V.

Date of Degree

5-12-2012

Document Type

Dissertation - Open Access

Major

Forest Products

Degree Name

Doctor of Philosophy (Ph.D)

College

College of Forest Resources

Department

Department of Sustainable Bioproducts

Abstract

Pentachlorophenol (PCP) is widely used as a wood preservative for wood products. It has been proposed that a modified PCP carrier system based on a diesel/biodiesel mixture should be used in place of the conventional diesel/KB3 carrier, but there is some question as to whether or not this modified carrier system can provide the same service life for wood products treated with PCP. The main objectives of this research were to evaluate: 1) the comparative biodegradability of PCP in soil containing either diesel/KB3 or diesel/biodiesel, and 2) the comparative decay resistance of wood treated with formulations containing either diesel/KB3 or diesel/biodiesel. For the biodegradability test a six month study was conducted to evaluate the remediation of PCP in the presence of either biodiesel or diesel in soil. Different percentages of biodiesel, diesel and PCP were mixed with clean soil and samples were taken and analyzed. The results showed significant reductions over time in oil and grease concentration, PCP concentration and toxicity for soils amended with both of these preservatives. The addition of biodiesel and PCP to the soil resulted in a significant increase in the Toxicity Characteristic Leaching Potential (TCLP) levels of PCP, suggesting that the co-metabolic effect of biodiesel on microorganisms could accelerate the degradation of PCP in soil. Also, a two year efficacy study using an accelerated soil contact decay test was initiated to compare the performance of treated wood with diesel/KB3 carrier and diesel/biodiesel carrier both with and without PCP. The residual hydrocarbon levels, PCP reduction, toxicity and leaching of PCP of the samples remained at the same level for treatments with similar PCP retention values for both of these carriers. Wood treated with PCP in two different carriers, the rate of decay was generally greater—particularly for the highest PCP retention level—for the biodiesel/diesel formulation, but this difference was not statistically significant. This study suggests that PCP formulated in a biodiesel/diesel carrier is not as effective as the conventional diesel/KB3 formulation against wood decay fungi. However, additional long term field stake tests will be required to determine the practical significance of this determination.

URI

https://hdl.handle.net/11668/16612

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