Environmental Chemistry Commons^™

Potentially Massive And Global Non-Pyrogenic Production Of Condensed "Black" Carbon Through Biomass Oxidation, Aleksandar I. Goranov, Hongmei Chen, Jianshu Duan, Satish C. B. Myneni, Patrick G. Hatcher

Chemistry & Biochemistry Faculty Publications

With the increased occurrences of wildfires worldwide, there has been an increase in scientific interest surrounding the chemistry of fire-derived "black" carbon (BC). Traditionally, wildfire research has assumed that condensed aromatic carbon (ConAC) is exclusively produced via combustion, and thus, ConAC is equated to BC. However, the lack of correlations between ConAC in soils or rivers and wildfire history suggests that ConAC may be produced non-pyrogenically. Here, we show quantitative evidence that this occurs during the oxidation of biomass with environmentally ubiquitous hydroxyl radicals. Pine wood boards exposed to iron nails and natural weather conditions for 12 years yielded a …

Bioethanol Production: Glucose Testing And Quantification Using Dns Analysis And Addition Analytical Methods, Dineen Vogler, Barnabas Gikonyo

McNair Scholars Program

The search for alternative ways to create a more sustainable and environmentally friendly source of energy, other than fossil fuels, has been ongoing for many years. Particularly, the production of biofuels has become of interest. One effort has been through the creation of first-generation biofuels that curb greenhouse gas emissions, unlike fossil fuels. However, first generation biofuels lead to the increase in food prices which negatively impacts developing countries, as they use food sources to produce biofuel. To mitigate this issue, second generation biofuels are considered as a better alternative. Instead of hindering the food supply, second generation biofuels aim …

Effects Of Nitrogen Depletion On The Biosorption Capacities Of Neochloris Minuta And Neochloris Alveolaris For Five Heavy Metals, Dimitri Giarikos, Jessica Brown, Reza Razeghifard, Duy Vo, Ammy Castillo, Nikhil Nagabandi, Justin Gaffney, Miriam Zelden, Anna Antakshinova, Sara Rodriguez, Safiyah Muhammad

Chemistry and Physics Faculty Articles

Neochloris minuta and Neochloris alveolaris grown in nitrogen-rich (+ N) and nitrogen-depleted (-N) media were tested for their heavy metal maximum biosorption capacities (q_max) and adsorption percent efficiencies (R%). By removing nitrogen from the growth media, both algal species showed an increase in their lipid content and a decrease in their protein content. Langmuir and Freundlich adsorption isotherms were used to determine the q_max and adsorption efficiencies of the + N and −N algae in the recovery of Pb²⁺, Cd²⁺, Zn²⁺, Cu²⁺, and Ni²⁺. When comparing the …

Oxidative Depolymerization Of Lignin To Low Molecular Weight Aromatics, Yang Song

Theses and Dissertations--Chemistry

To date, most lignocellulosic biorefinery strategies have focused on optimizing conversion of cellulose to ethanol, leaving lignin as an underutilized biomass constituent. Lignin is engineered by nature with the intent to protect plants from chemical and biological attack; this leaves lignin with high structural irregularity and recalcitrance, rendering conversion of the lignin macromolecule to valuable products particularly challenging. Nevertheless, given that the economics of cellulosic ethanol production are strongly dependent on the value that can be obtained for the lignin co-product, the successful valorization of lignin is a crucial step in the transition towards a bio-based economy.

This thesis focuses …

Production And Harvest Of Microalgae In Wastewater Raceways With Resource Recycling, Alexander Colin Roberts

Master's Theses

Microalgae can be grown on municipal wastewater media to both treat the wastewater and produce feedstock for algae biofuel production. However the reliability of treatment must be demonstrated, as well as high areal algae productivity on recycled wastewater media and efficient sedimentation harvesting. This processes was studied at pilot scale in the present research.

A pilot facility was operated with nine CO₂-supplemented raceway ponds, each with a 33-m² surface area and a 0.3-m depth, continuously from March 6, 2013 through September 24, 2014. The ponds were operated as three sets of triplicates with two sets continuously fed …

Carbon Sequestration In Tidal Salt Marshes And Mangrove Ecosystems, Carlos Eduardo Quintana-Alcantara

Master's Projects and Capstones

Wetlands are dynamic systems that provide support to vital environmental functions and services. Wetlands take part in the global carbon cycle by holding organic carbon in biomass, soils and sediments. In recent years, the wetland carbon sequestration capacity has been researched worldwide due to the increase of the concentrations of greenhouse gasses implicated in global warming and climate change. Although coastal wetlands release the greenhouse gasses carbon dioxide, methane and nitrous oxide, these ecosystems maintain high performance in offsetting significant amounts of atmospheric carbon. This paper investigated the carbon sequestration capacity of coastal wetland ecosystems summarizing the environmental conditions and …

Spectroscopic Study Of Uranium (Vi) Reduction By Plant Biomass, Margaret C. Murphy, John Bargar, Noémie Janot

STAR Program Research Presentations

Uranium is a common and problematic groundwater contaminant at Department of Energy legacy sites. At the former uranium ore processing plant at Rifle, Colorado, sediments rich in decayed plant biomass contain large concentrations of uranium that are slowly being released back to the aquifer. To simulate the reaction that occurs in organic rich sediments of the Rifle aquifer, biomass was incubated in U (VI) bearing groundwater. Carbon X-ray absorption spectroscopy (XAS) was then used to measure if uranium was bound to the biomass. When uranium binds to biomass the peaks in the C XAS spectra will change shape. Uranium L …

Determination Of Kinetic Parameters From The Thermogravimetric Data Set Of Biomass Samples, Karol Postawa, Wojciech M. Budzianowski

Wojciech Budzianowski

This article describes methods of the determination of kinetic parameters from the thermogravimetric data set of biomass samples. It presents the methodology of the research, description of the needed equipment, and the method of analysis of thermogravimetric data. It describes both methodology of obtaining quantitative data such as kinetic parameters as well as of obtaining qualitative data like the composition of biomass. The study is focused mainly on plant biomass because it is easy in harvesting and preparation. Methodology is shown on the sample containing corn stover which is subsequently pyrolysed. The investigated sample show the kinetic of first order …