Thesis
Evolution of acidic functional groups on biochars by ozone oxidation to improve performance as a soil amendment
Washington State University
Master of Science (MS), Washington State University
2011
Handle:
https://hdl.handle.net/2376/103245
Abstract
The effects of ozone oxidation on the surface chemistry and physical properties of three biochars produced from feedstocks available in Washington State (pine wood, pine bark and anaerobic digester fiber) have been investigated and compared to results obtained from activated carbon. An ozone stream was passed over a fixed bed of chars to rapidly oxidize the surface material for varying treatment times. Changes in proximate and bulk elemental composition, surface area, surface pH, surface acidic groups, crystallinity, cation and anion exchange capacity, and ammonium and phosphate adsorption capacity were determined for each sample. Results indicate that all materials could be oxidized to varying degrees by ozone. The surface carboxyl groups increased with exposure time. Oxidation times of approximately 10 minutes were sufficient to develop the majority of acid sites present after one hour of treatment. T he materials with high surface area were rapidly gasified by ozone, with approximately 20-30% mass loss after one hour. Acid sites are formed from the degradation of fixed aromatic rings (fixed carbons), present in the char, as opposed to the aliphatic portion which is typically oxidized preferentially in heated oxygen treatments. The development of surface acidic sites increased the cation exchange capacity of each material significantly but had little or no effect on phosphorus removal capacity of each material.
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Details
- Title
- Evolution of acidic functional groups on biochars by ozone oxidation to improve performance as a soil amendment
- Creators
- Matthew Smith
- Contributors
- Manuel Garcia-Perez (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Biological Systems Engineering, Department of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; Pullman, Wash. :
- Identifiers
- 99900525180001842
- Language
- English
- Resource Type
- Thesis