Browsing by Subject "Biomass conversion."
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Item Effect of varying feedstock-pretreatment chemistry combinations on the production of potentially inhibitory degradation products in biomass hydrolysates.(2009-06-02T17:54:51Z) Du, Bowen.; Chambliss, C. Kevin.; Environmental Science.; Baylor University. Dept. of Environmental Science.A variety of inhibitory degradation products are produced during pretreatment of lignocellulosic biomass. Production and release of these degradation products is highly affected by the pH and redox potential of pretreatment reactions. Qualitative and quantitative interrogation of hydrolysates is paramount to identifying potential correlations between pretreatment chemistries and microbial inhibition in downstream bioconversion processes. In the present study, corn stover, poplar, and pine wood were pretreated under eight different chemical conditions, which are representative of leading pretreatment processes that have been investigated in recent years. Pretreatment processes included: 0.7% H2SO4, 0.07% H2SO4, liquid hot water, wet oxidation, neutral buffer solution, aqueous ammonia, lime, and oxidative lime. Forty lignocellulosic degradation products resulting from pretreatment were analyzed by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) and ion chromatography (IC) in order to determine correlations between concentrations of inhibitory degradation products and pretreatment chemistry.Item Synthesis, characterization, and applications of redox-mediated ion exchangers.(2007-12-04T19:51:40Z) Feazell, Monica N.; Chambliss, C. Kevin.; Chemistry and Biochemistry.; Baylor University. Dept. of Chemistry and Biochemistry.The technology for conversion of lignocellulosic biomass resources to fuels and chemicals has been under development for decades. There are many process configurations for conversion of biomass to ethanol, one of the well-studied technologies is to use a dilute-acid-catalyzed pretreatment followed by enzymatic hydrolysis and fermentation to produce the ethanol. However, the pretreatment product mixture, typically called hydrolysate, contains a variety of degradation products such as aliphatic and aromatic acids, phenols, and aromatic aldehydes. These degradation products formed can be considered potential fermentation inhibitors, and they can be a restricting factor in the achievability of biotechnological conversions of lignocellulosics to ethanol. This project seeks to contribute to the development of biomass conversion technologies by demonstrating a novel process enabling: 1) simultaneous extraction of organic acids and phenols through reactive ion exchange, 2) quantitative recovery of extracted components into aqueous solution, and 3) regeneration of reactive ion exchangers using redox chemistry. The organometallic complex Fe([eta]5-C5H5)([eta]5-10-C2B9H8(n-C12H25)2) is used in combination with tetra-n-heptylammonium hydroxide salt to demonstrate an improved R2ER for the extraction of acids from aqueous solutions. The metal complex itself remains in its neutral state and only acts as a spectator during the extraction step. New synthetic approaches to a single-component reagent have been developed in this study. The new organometallics synthesized have the principal advantage of reducing the process to a one-reagent. In this case the organometallic complex acts as an extractant instead of a spectator. Seven new compounds were synthesized and characterized, and the uses of Fe([eta]5–C5H5)([eta]5-10-(N(CH3)3)-7,8-C2B9H8(n-C12H25)2)] in a R2ER process were studied for the extraction of perchlorate from aqueous solutions.