An environmental and chemical engineer at Washington University in St. Louis has received more than $1 million to study interfacial reactions that relate to energy, environmental and biomedical systems involving a variety of earth-abundant materials. With the newly developed strategies, these materials can be used most effectively at their smallest size — the nanoscale.
, associate professor of energy, environmental & chemical engineering in the School of Engineering & Applied Science, has received three grants from the National Science Foundation for this work, totaling nearly $1.03 million over three years.
One grant will fund research into forming manganese oxides in aqueous systems using our most unlimited resource —sunlight. The ultimate goal is to make manganese ions into “nanosheets” —sheets of manganese oxide nanoparticles — that could be used as a sustainable energy material in lithium ion batteries. This new understanding of the changes in manganese in aqueous environments also is critical in controlling water quality and acid mine drainage, Jun said. Results of this work could also influence the development of other energy materials using green chemistry principles.
Another grant, in collaboration with Srikanth Singamaneni, associate professor of materials science, aims to find new ways to meet the growing demand for fresh water. The grant will fund their efforts to develop new photothermal membranes made of nanostructures that could prevent the buildup of microorganisms and biofilms. This research project will be the first to use the photothermal capability of gold nanostars, graphene oxide and molybdenum sulfide for water purification.
The team will develop molybdenum sulfide, an inexpensive and abundant material commonly used as pencil lead, to develop 2-D sheet materials for purifying water. Because chemically-exfoliated molybdenum sulfide is a highly promising 2-D optical and electronic material, new information about water-molybdenum sulfide interfacial reactions also will help to design safer and more sustainable nanomaterials for electronic applications, Jun said.
“Photothermal materials can absorb light effectively and turn it into localized heat that will kill microorganisms,” Jun said.
“We want to better understand the materials’ formation and reactivities with water to develop novel water purification methods. This work investigates the unexplored potential of inexpensive and abundant molybdenum sulfide as a replacement for expensive materials to achieve water sustainability and meet this major global challenge.”
A third project, a collaborative grant with Stavros Thomopoulos, professor of biomechanics, director of the Carroll Laboratories for Orthopedic Surgery and vice chair of Basic Research in Orthopedic Surgery at Columbia University, blends environmental chemistry with biomedicine.
Jun and Thomopoulos will study how and where calcium phosphate forms in the body to create new bone and improve tendon-to-bone attachment healing. In particular, they will look at how the bones form and how their mechanical properties change from the nanoscale to larger scales, as well as look for ways to trigger quicker initiation of calcium phosphate formation to speed healing.
“Our blood has an abundance of calcium and phosphate, but bone does not form everywhere,” Jun said. “It obeys biological, chemical and electrical signals to form in specific locations and not in others. This is intriguing. We’re trying to decipher that information and control where it should form and how fast we can form it with proper stimulants.”
The findings from this work could also be applied to understanding the chemical reaction of calcium oxalate to form kidney stones. In addition, Jun may apply the principles to recovering phosphate from wastewater for use as fertilizer.
All three projects will include an outreach component to local middle and high school students in cooperation with the university’s Institute for School Partnership, as well as research opportunities for undergraduate and graduate students.
The School of Engineering & Applied Science at Washington University in St. Louis focuses intellectual efforts through a new convergence paradigm and builds on strengths, particularly as applied to medicine and health, energy and environment, entrepreneurship and security. With 88 tenured/tenure-track and 40 additional full-time faculty, 1,300 undergraduate students, more than 900 graduate students and more than 23,000 alumni, we are working to leverage our partnerships with academic and industry partners — across disciplines and across the world — to contribute to solving the greatest global challenges of the 21st century.