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dc.contributor.advisorPeltier, Edward
dc.contributor.authorGupta, Abhinav
dc.date.accessioned2015-09-07T21:04:56Z
dc.date.available2015-09-07T21:04:56Z
dc.date.issued2014-12-31
dc.date.submitted2014
dc.identifier.otherhttp://dissertations.umi.com/ku:13821
dc.identifier.urihttp://hdl.handle.net/1808/18385
dc.description.abstractAlgae has become a major research focus in the past few years. Treatments such as pyrolysis, hydrothermal carbonization, hydrothermal liquefaction, hydrothermal gasification are being used to process algae and yield products such as lipids, lipid-rich hydrochar, biocrude, methane and hydrogen. These treatments also produce biochars as a product of thermal decomposition of organic material under limited supply of oxygen at temperatures less than 700oC. Biochars have potential for use as a soil amendment, both to improve soil quality and to sequester carbon. Algal biochar used in this study was produced by hydrothermal liquefaction of algae at 350oC which was grown at Lawrence Wastewater Treatment Plant using municipal wastewater as the feedstock. This biochar was black in color, very smooth & powdery in texture and tremendously hydrophobic in nature. This study was aimed at extraction and characterization of phosphorus from this organic algal biochar. Since biochars are often used as a mixture with soils and there are no currently established methods for extraction of phosphorus from biochars, various soil P extraction methods were studied and investigated to be used on this biochar. For estimation of total P, acid digestion of biochar with sulphuric acid was attempted, but failed to achieve good digestion. Microwave acid digestion was tried with different combinations of acids, with reverse aqua regia (HCl:HNO3::1:3) working best to digest this algal biochar. Most elements that were analyzed in the biochar, including Ca and P were present in biochar at a higher concentration than in algae. ICP analysis of the digested samples gave a total P content of 7.4±0.58 % by wt. which was 3.2 times the total P in algae (2.3±0.03% by. wt.). Similarly, a high amount of total Ca was also found in the biochar (17.10±1.31% by wt.) as compared to 5.70±0.18% by wt. in algae. Approximately 89% of calcium and 95% of phosphorus initially present in the algae were recovered from the biochar after hydrothermal liquefaction. Because of the high Ca content, it was thought that P in char might be mostly present as calcium phosphates. The Olsen Method was used to estimate bioavailable phosphorus from biochar because it is best suited for calcareous soils. On ICP analysis, a very small fraction (less than 1%) of total P in algal biochar was found to be extractable by the Olsen reagent. However, when shaking time was doubled from 30 minutes to 60 minutes in Olsen method, the amount of soluble P doubled from 287±110 ppm to 581±116 ppm. This meant that the calcium associated P in biochar may slowly release over time. Water extraction was completely ineffective in extracting any P from biochar. These low Olsen and water extraction P results may be because of insufficient contact of biochar with reagents owing to its hydrophobicity. Biochar was difficult to mix well with reagents for estimation of bioavailable P due to its hydrophobic nature. Heating at 105oC overnight to get rid of the volatile organic fractions did not improve mixing. This study provides a preliminary idea of the nature of P in this biochar. Based on the extraction results, it appears that P in this biochar is mostly unavailable to plants. Hydrophobic nature of biochar may hinder its ability to mix well with soil and thus it may need to be treated before being used for soil amendment. There is scope for further research on this biochar including testing it with different extraction methods, performing extractions after washing biochar with an organic solvent, engineering the hydrophobicity of this biochar by altering the production conditions, and studying the actual long-term release of P under real or simulated field conditions.
dc.format.extent60 pages
dc.language.isoen
dc.publisherUniversity of Kansas
dc.rightsCopyright held by the author.
dc.subjectEnvironmental engineering
dc.subjectAlgae
dc.subjectBiochar
dc.subjectCharacterization
dc.subjectExtraction
dc.subjectOlsen
dc.subjectPhosphorus
dc.titleExtraction and characterization of phosphorus from organic algal biochar
dc.typeThesis
dc.contributor.cmtememberSturm, Belinda
dc.contributor.cmtememberWilliams, Susan
dc.thesis.degreeDisciplineCivil, Environmental & Architectural Engineering
dc.thesis.degreeLevelM.S.
dc.rights.accessrightsopenAccess


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