2023 Design and Research Conference

Extraction and Characterization of Sugars from Biomass using Deep Eutectic Solvents

Team Member: Daniel L. Morris

Advisor: Dr. Joan Lynam

Climate change is a pressing issue that could soon lead to major problems for the global environment. Finding cleaner alternatives to traditional fuel sources can mitigate some of these effects. Biofuels are among the alternatives that researchers have focused on in recent years. Biofuels are made from biomass and are more carbon neutral than fossil fuels. The focus of this project is to isolate sugars from rice husks, sugarcane bagasse, and coffee chaff for use in biofuel synthesis. Using hydrothermal carbonization (HTC), researchers can separate the cellulose and hemicellulose from the lignin present in the biomass. To further extract specific sugars, a 2:1 acetic acid/choline chloride, a 10:1 lactic acid/choline chloride, or a 1:1 formic acid/choline chloride deep eutectic solvent (DES) is used as the solvent within the HTC process. Using high-performance liquid chromatography (HPLC), we successfully extracted glucose, galactose, and fructose from the biomass samples.

Investigation of Fluorinated Anions Encapsulated by Cyanostar Using NMR Spectroscopy

Team Member: Spencer Stelly

Advisor: Dr. Elisabeth Fatila

Fluorinated anions are infamous for their utility as ligands to transition metal and lanthanide ions, as well as their persistence in the environment. By electrostatically binding with anions, size-selective macrocyclic ionophores effectively isolate anions from solution, allowing for a potential means of environmental remediation. Previously, we investigated the binding of 1,1,1,5,5,5-hexafluroacetylacetone (hfac) with the five-fold symmetric macrocycle Cyanostar (CS), which uses weak C-H bond donors to complex anions. Here, unusual 1H and 19F spectroscopic signatures for hfac in chloroform were observed as the alkene signal diminished at low concentrations and reappeared at high concentrations. We investigated the effect of solvent systems on the binding of fluorinated carboxylate anions by studying CS binding in chloroform, methylene chloride, and tetrahydrofuran. These studies will be conducted using 1H and 19F nuclear magnetic resonance (NMR) spectroscopy, and crystallographic data and infrared spectroscopic data will be used for comparison. From these findings, we can determine how CS binds fluorinated organic anions and whether decomposition, chemical exchange, or solvent effects affect the NMR spectrum. These results will assist others in investigating the binding of fluorinated species with macrocycles, and provide insight into the solution behavior of fluorinated species.

Effects of Arginine on the Antimicrobial Activity of AMPs

Team Member: Samantha Townsend

Advisors: Dr. Scott Poh and Dr. Rebecca Giorno-McConnell

The recent increase in multidrug-resistant bacteria poses a serious threat to public health. A promising alternative to combat antibiotic resistance is the use of antimicrobial peptides (AMPs). The most promising AMPs are those with shorter sequences and a cationic charge because they more easily bind to and penetrate the anionic cell membrane of target cells. Although AMPs tend to be less toxic than antibiotic therapeutics, they are still promising given their broader range of activity and lower potential for resistance evolution. To determine if the addition of cationic residues would increase antimicrobial activity, we added two arginine residues to the N-terminus (RRWLRRIKAWLRR [2(Arg)-RR] and RRWLRRIKAWLRRIKA [2(Arg)-RIKA]) of two recently characterized AMPs (WLRRIKAWLRR [RR] and WLRRIKAWLRRIKA [RIKA]). We then synthesized the modified peptides using solid-phase peptide synthesis and evaluated them for antimicrobial activity against Escherichia coli and Staphylococcus epidermidis using a minimal inhibitory concentration (MIC) assay. In this study, 2(Arg)-RR and 2(Arg)-RIKA demonstrated less antimicrobial activity with MICs that are 2-3x higher than observed by RR and RIKA. We believe this decrease in toxicity is due to a reduced ability of the peptides to destabilize the bacterial membrane and can be attributed to their hydrophobic profiles.

Utilization of Mechanochemistry for Complexation of lanthanides with Insoluble Polypyridyl Ligands

Team Member: Natalya O’Haver

Advisor: Dr. Elisabeth Fatila

With the rising financial and environmental costs associated with solvent usage, more sustainable methods for conducting chemical reactions have been sought out. Mechanochemistry is a facet of green chemistry that can reduce the amount of solvent required for a reaction. Additional benefits of mechanochemistry include the discovery of compounds that are inaccessible through conventional solution synthesis and the ability to react with compounds that are insoluble. Using manual grinding via mortar and pestle as well as ball-milling, we determined the scope of mechanochemical coordination reactions with insoluble polypyridyl ligands. We followed the reactions using powder x-ray diffraction and Fourier-transform infrared spectroscopy and determined purity using differential scanning calorimetry. We obtained single crystal structures when possible and compared them to the bulk material. For further studies, we will include in situ monitoring of these mechanochemical reactions.

Determination of PAH Concentration in Soil Samples using Fluorescence Spectroscopy

Team Member: James Walker Hankinson

Advisor: Dr. Sven Eklund

Polycyclic aromatic hydrocarbons (PAHs) are simple nonpolar compounds that are the result of energy production via the burning of organic compounds. The nonpolar characteristics of these polycyclic aromatic hydrocarbons make them liposoluble compounds. Absorption of PAHS by the human body through ingestion, inhalation, or dermal contact can lead to a variety of health problems, ranging from relatively minor symptoms such as dizziness and nausea, to things much more serious such as liver failure. With these effects, it is important to monitor PAH concentrations to protect the health of humans, as well as the conservation of ecosystems. Soil samples were collected from Baton Rouge and Ruston, Louisiana, and then analyzed via fluorescence spectroscopy. This analysis gave extremely low-intensity values for fluorescence at 400 nm and 424 nm, values so low that the calibration curves created using standard solutions with known PAH concentrations could not compute a concentration value. It was determined that this was due to the samples being collected in rural areas in each city that did not possess any industrial presence as well as fewer vehicles in transit, resulting in either no or minimal PAH accumulation in the soil.

Break and Program Awards

Assessing Polymeric Membranes for Styrene Outgassing Prevention in CIPP

Team Member: Mark Hesser

Advisor: Dr. Sven Eklund

We evaluated various polymeric membranes to use in cure-in-place pipeline (CIPP) liner storage for manufacturing facilities, as well as during refrigerated shipment to prevent the release of styrene outgassing, which can pose acute exposure hazards at levels of 80 ppm or more. To determine the rate of permeation, outgassing was measured through specially prepared glass vials, which were divided by the polymeric membranes into two chambers. We infused the chamber below the membrane with styrene monomer and sampled the gaseous atmosphere above the membrane. We injected the sample into a gas chromatograph with a flame ionization detector (FID) and calculated the permeation rate over 15 days by sampling the vial. We then created calibration curves by utilizing styrene monomer dissolved in benzene. Furthermore, we took scanning electron microscopy (SEM) porosity measurements on the membranes to establish a correlation between permeation rates.

Synthesis and Characterization of Frontally Polymerized Geopolymer Cement with Organosilane Crosslinkers

Team Member: Adam Soileau

Advisors: Dr. Sven Eklund and Dr. Shaurav Alam

Ordinary Portland cement (OPC) is one of the most widely used construction materials. OPC is produced by heating limestone (CaCO₃) to produce calcium oxide (CaO) and carbon dioxide (CO₂). Thus, OPC production causes the release of large quantities of CO₂. Our research focuses on a sustainable alternative to OPC which is class-F fly ash-based geopolymer cementitious (GPC) material. Making geopolymer (fly ash, NaOH, and Na₂SiO₃) currently requires continuous heating at 70^°C for five hours in an oven. In this research, we attempt to eliminate the oven by producing heat through the frontal polymerization (FP) process. For our experimentation, we blended inorganic geopolymer materials with an organic monomer (MMA), crosslinker (TMPTA), solvent (DMSO), and an initiator (Aliquat persulfate) to produce cement material through thermal FP. Through the thermal FP, heat was applied on a single spot or surface long enough to initiate polymerization and then removed. This novel cementation process serves as a rapid repairing material in construction operations and may open the possibility of new 3-D printable cementitious material. However, in the current frontally polymerized GPC (FPGPC), no chemical bonding exists within the inorganic and organic components. Studies have shown that the inclusion of organo-silane has the potential to create a crosslink between the inorganic and organic components of FPGPC. We expect these organo-silane crosslinkers to improve the bonds between the organic polymers and inorganic GPC. We will use IR and NMR spectroscopy plus a compression testing device to test and evaluate the results and ensure bonding and the newly produced cementitious material’s compressive strength compared to the regular OPC.

Discovery of Novel Centrifugal Thin Layer Chromatography Reversed Stationary Phase

Team Member: Jacquelin LaBerteaux

Advisor: Dr. Sven Eklund

Centrifugal thin-layer chromatography (CTLC) is a useful process for the separation and purification of biologically active molecules from natural product extracts. Presently, the only commercial discs used for CTLC separations are made of silica gel with a water-soluble gypsum binder. This type of disc can only be used for normal phase chromatography, which limits the types of molecules that can be separated. The availability of reversed phase chromatography discs would offer the ability to separate a wider range of molecules, which include many nonpolar natural product extracts. In this research, we have studied the use of 3-methacryloxypropyltrimethoxysilane (MPTMS) to improve the bonding between silica particles. The particles were further functionalized with octyl silane (C8) to make the particles nonpolar for reversed-phase CTLC. The particles were characterized through FTIR, SEM, DLS, and CNMR.

Isolation of Magnolia Grandiflora Parthenolide via Reversed Phase Flash Chromatography

Team Member: Natalie Stewart

Advisor: Dr. Sven Eklund

Parthenolide is a sesquiterpene lactone used in drug research due to its uses in treating many ailments such as fevers, migraines, arthritis, etc. The natural product is commonly extracted from the feverfew plant (Tanacetum parthenium L.), and, more recently, from magnolia leaves (Magnolia grandiflora), which have a higher concentration of parthenolide than feverfew and are in large abundance in Louisiana. In this study, we obtained parthenolide from magnolia leaves from a previously optimized Soxhlet extraction using 95 percent ethanol for two hours. We then separated the extraction products using a C-18 flash chromatography column with a 45/55 percent water/acetonitrile mobile phase and collected them in 30-second intervals. Each extraction fraction was then dried, and the products were characterized using FTIR and NMR spectroscopy.

Break and Program Awards

Advanced Wood Products Infused with Halloysite for Increased Natural Resistance

Team Member: Akeena Obaze

Advisor: Dr. Yuri Lvov

Halloysites are nanotubes made of aluminosilicate; the formula is with Al-(OH)₃ on the inside and Si-O bonds on the outside. This unique molecular configuration of halloysites allows them to be positive inside and negative on the outside of the tube. We will load silver acetate into the halloysite nanotubes (HNTs) and impregnate these natural nanotubes in wood by spraying the halloysite onto the wood surface with a high-pressure spray gun. The silver halloysite coating would show an increase in the wood products’ durability, flame resistance, and mold resistance.

Investigation of Metal-Organic Complexes Dope in Polymers for Scintillations Uses

Team Member: Treylan Steveson

Advisor: Dr. Elisabeth Fatila

For this LaSpace-sponsored project, we worked to develop scintillation polymers for use on extended missions in space. Scintillators are needed to detect radiation and keep astronauts safe. For this project, we synthesized metal-organic complexes with europium, cerium, and terbium. Since lanthanides absorb light poorly, we coordinated ligands to the metal center for greater light absorption. In addition, we investigated simple carboxylate ligands including trifluoroacetate and pyridine carboxylates as ligands to lanthanides as luminescent dopants. We characterized our products using Fourier-transform infrared spectroscopy (FTIR), multi-nuclear NMR spectroscopy, powder, and single x-ray diffraction (XRD). We determined the optical properties using UV-Vis and fluorescence measurements. Differential scanning calorimetry (DSC) was used for the determination of thermal stability and purity. We tested these compounds for solubility in organic solvents prior to doping. For the polymerization of MMA (methyl methacrylate), we dissolved our metal-organic complex in MMA with a thermal initiator and cured it at 80 °C. The polymerization procedure resulted in optically clear plastics suitable for scintillation measurements that luminesce cyan to red under 365 nm light. Future work in collaboration with the Physics program will involve investigating the performance of these scintillators to ionizing radiation sources and cosmic events.

Synthesis and Characterization of Monolayer-Protected Nickel Nanoparticles

Team Member: Bailey Parr

Advisor: Dr. Sven Eklund

We synthesized nickel nanoparticles protected by a self-assembled glutathione monolayer by dissolving a 1:1 mole ratio of Ni(II)Br₂ and glutathione in water and adding a concentrated solution of NaBH4 dropwise while degassing the solution of oxygen through the use of N₂ gas. This allowed the ligands to bind to the nickel clusters before they were able to aggregate or oxidize. We chose glutathione as the ligand material to allow the particles to be water-soluble and analyzed the particles using H-NMR, IR, UV-Vis, Raman, DLS, and TGA.

Faculty Meeting with Advisory Board