Masters Theses

Orcid ID

Date of Award


Degree Type


Degree Name

Master of Science


Biosystems Engineering

Major Professor

Nicole Labbe, Nourredine H. Abdoulmoumine

Committee Members

Xiaofei Ye


Recovery of the wood preservative copper naphthenate (CN) from end-of-life railroad ties was investigated to promote the secondary use of this biomass as a fuel source and mitigate the negative impacts of landfilling and other alternative tie disposal methods. Thermal desorption of naphthenic acids from CN-treated ties preceded inorganic extraction with ethylenediaminetetraacetic acid (EDTA) and biodegradable chelating agents, 2,6-pyridine dicarboxylic acid (PDA) and 1-hydroxy ethylidene-1,1-disphosphonic acid (HEDP). Organic preservative components were recovered from thermal pretreatment at temperatures between 225 and 300 °C. This thermal desorption also mirrored torrefaction by increasing the ties’ higher heating value and carbon content, in addition to lowering the moisture content within the biomass. These effects improved the biomass properties for use as a thermochemical conversion feedstock. Preservative component recovery was assessed at micro-, bench-, and pilot-scales, demonstrating scalability of the proposed process. Extraction efficiency of copper and other naturally present inorganics with PDA after thermal desorption was the most effective of those tested, further upgrading the properties of the biomass for pyrolysis. The ash content of the biomass was decreased by up to 64 % using PDA, and 100 % of copper was removed from both the raw sample and that desorbed at 225 °C specifically. Estimations of the bio-oil yields that would be generated from subsequent fast pyrolysis of the ties were completed based on a review of literature. The sample that has undergone both pretreatment steps is expected to generate the highest quantity of bio-oil from subsequent fast pyrolysis, as well as the highest quality.


A version of Chapter II of this thesis was originally published by Holly L. Haber, Pyoungchung Kim, Stephen C. Chmely, Jeff Lloyd, Yagya N. Regmi, Nourredine Abdoulmoumine and Nicole Labbé. I has been reprinted with permission from “Environmentally Friendly Process for Recovery of Wood Preservative from Used Copper-Naphthenate Treated Railroad Ties” in American Chemical Society’s Sustainable Chemistry and Engineering, 2017, DOI: 10.1021/acssuschemeng.7b02760. Copyright 2017 American Chemical Society.

Files over 3MB may be slow to open. For best results, right-click and select "save as..."