Effects of Sulfur Content, Crosslinking, and pH on Metal Binding in Imidazolium Polysulfides
Faculty Mentor Information
Dr. Courtney Jenkins, Idaho State University
Presentation Date
7-15-2026
Abstract
Sulfur is an abundant waste product of petroleum, making it accessible and inexpensive. Inverse vulcanization is a polymerization method where sulfur acts as the solvent, monomer, and initiator to create high-sulfur-content polysulfides. These polysulfides are known for binding mercury and the inclusion of imidazole groups yield especially effective gold sorbents. Prior work demonstrated that poly(S-1-vinylimidazole), p(S-VinI), has a significantly higher binding capacity than polysulfides made with imidazolium crosslinkers. Unlike VinI, these other systems utilize difunctional monomers, forming crosslinked polysulfides that are permanently charged. This work sought to understand the roles of protonation and crosslinking in metal sorption. Poly(S-VinI) was synthesized at various pHs to explore the effects of protonation on the chemical properties. Alternative imidazolium compounds with variations in sulfur content were tested independently to examine the effects of structural changes of crosslinking, charge, and sulfur chain length on metal sorption. As a result, crosslinking and deprotonation increased mercury removal. Sulfur content’s influence on metal binding was dependent on the monomer it was synthesized with. Silica as a polymer display limited metal removal and carbon black increased removal of mercury, and additionally removed selenium, barium, lead, and copper.
Effects of Sulfur Content, Crosslinking, and pH on Metal Binding in Imidazolium Polysulfides
Sulfur is an abundant waste product of petroleum, making it accessible and inexpensive. Inverse vulcanization is a polymerization method where sulfur acts as the solvent, monomer, and initiator to create high-sulfur-content polysulfides. These polysulfides are known for binding mercury and the inclusion of imidazole groups yield especially effective gold sorbents. Prior work demonstrated that poly(S-1-vinylimidazole), p(S-VinI), has a significantly higher binding capacity than polysulfides made with imidazolium crosslinkers. Unlike VinI, these other systems utilize difunctional monomers, forming crosslinked polysulfides that are permanently charged. This work sought to understand the roles of protonation and crosslinking in metal sorption. Poly(S-VinI) was synthesized at various pHs to explore the effects of protonation on the chemical properties. Alternative imidazolium compounds with variations in sulfur content were tested independently to examine the effects of structural changes of crosslinking, charge, and sulfur chain length on metal sorption. As a result, crosslinking and deprotonation increased mercury removal. Sulfur content’s influence on metal binding was dependent on the monomer it was synthesized with. Silica as a polymer display limited metal removal and carbon black increased removal of mercury, and additionally removed selenium, barium, lead, and copper.