Date of Award
Spring 4-7-2026
Document Type
Thesis
Degree Name
Master of Science (MS)
Department
Chemistry
First Advisor
James Gardinier
Second Advisor
Adam Fiedler
Third Advisor
Alexander Erickson
Abstract
Desulfurization of fuels is a critical process for reducing sulfur contents in petroleum-based fuels to mitigate environmental pollution and meet the regulatory standards. Among various pollutants, Sulfur is the deadliest as inhaling leads to coughing, shortness of breath, sinus problem as well as the death of brain cells. Petroleum has a number of organosulfur derivatives, for example in crude oil (0.1 to 6wt% sulfur), which should be removed before using in combustion engines and other applications. High sulfur containing petroleum products used in engines and power plants would lead to the formation of sulfurdioxide (SO2) which would contribute to the formation of acid rain that damages ecosystems, corrodes buildings and acidifies water bodies. Also sulfur compounds can poison catalysts used in refinery processes, particularly in catalytic converters and hydrotreating units. Hydrodesulfurization (HDS) is a high-pressure (150 to 250 psig) and high-temperature (200 to 425°C) process that uses hydrogen gas to reduce the sulfur in petroleum fractions (particularly diesel) to hydrogen sulfide, which is then readily separated from the fuel. Interestingly after the HDS, some thiophenes like benzothiophene, 4 methylbenzothiophene still survive which need further transformation that can be possible under extreme conditions or greater expenses. There are some available alternatives including biodesulfurization (BDS), adsorptive desulfurization (ADS), and extractive desulfurization (EDS). There are some issues associated with these techniques as they are costly and difficult to incorporate commercially. Most of the chemical oxidation of DBT by H2O2 or other potential oxidants like O2 is sluggish and requires catalytic activation. For industrial application solid supported heterogenous catalyst are preferred as they are easy to separate and recycle. So, we are aiming to find a replacement for expensive and toxic metal as well as strong organic photocatalysts to oxide DBT. The primary objective of our research is to investigate efficiency and potential environmental applications of the organic dyes for photooxidation of dibenzothiophene (DBT) under various conditions. The focus will be identifying the photooxidation products and determining the factors that influence the efficiency of sulfur removal. The aim is to assess the duration of photoreaction, amount of catalyst, solvents, temperature, and wavelength of light, amongst other factors. Then, we will use NMR instruments, mass spectrometers (GC/MS, MALDI TOF) techniques to analyze the product and determine the potential of DBT photooxidation as a practical desulfurization technique by evaluating its scalability and applicability in real world applications. Achieving ultra-low sulfur fuel standards is crucial for sustainable energy production and reducing the ecological footprint of fossil fuel consumption.