Date of Award

Spring 2022

Degree Type

Thesis

Degree Name

Doctor of Philosophy (PhD)

Department

Materials Science

Committee Chair

John Kirtley

First Advisor

Dario Prieto

Second Advisor

Karen Ward

Third Advisor

Jerry Downey

Fourth Advisor

Rob Walker

Abstract

Biochars are a class of carbonaceous materials possessing high degrees of structural and chemical disorder in both organic and inorganic constituent phases. Despite this disorder, and in some cases because of this disorder, biochars have shown strong performance in adsorbing and even sequestering contaminants from soil, surface water and air. Biochar is the carbonaceous, solid product of heating carbonaceous feedstock in an oxygen-limited environment above 250°C, usually sourced from inexpensive, locally available agricultural and forestry wastes which can otherwise be difficult and expensive to dispose of. Biochar possesses attractive functional properties like high specific surface area, high micropore volume, and tunable surface chemistry which are key to performance in separation technologies and environmental remediation. In this work, two high-performing biochars were investigated: one from cottonwood feedstock and one sourced from locally available bovine bone waste. In the wood-based biochar, the synergistic impacts of potassium content and lignin microstructure were investigated for their role in determining biochar structure and function. The performance of these biochars was tested in dynamic adsorption of gaseous ammonia, a growing threat to human and environmental health, in which all biochars outperformed a commercial activated carbon. Breakthrough times showed no correlation with surface area of the adsorbents, contrary to expectation. Biochar sourced from pyrolyzed bovine bone has shown strong performance against a range of other materials in removing Cu2+ from acid mine waste. In-depth characterization of the mineral and organic phases of this novel biochar revealed that disorder may be key to its strong performance in Cu2+ removal.

Comments

A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy: Materials Science.

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