Solar powered water purification

Zhe Zhang ’15 set out to learn about solar-powered water purification. But his summer research project has taught him at least as much about determination and hard work.

He has spent much of his summer trying to make one chemical reaction happen, which he originally assumed would take only a couple of days. But he takes that in stride. “It’s always fun to try different things and to finally get a solution,” he said. “I just don’t want to fail.”

Zhang has long had an interest in ways of using chemical reactions to purify water. Considering the world’s demand for potable water as well as the potential for energy shortages in the future, he thought developing a sun-powered water purification system would be important. Zhang was particularly interested in titanium dioxide, a semiconductor that is known to purify water when it is exposed to sunlight.

If only that process worked quickly.

“The process is not new, but it’s not efficient enough to be practical,” said Bill Bare, a Randolph chemistry professor advising Zhang on this research. “We’re hoping to make it a little more practical.”

Sunlight causes chemical reactions that increase energy in titanium dioxide atoms, causing the semiconductor to break down organic compounds. But it only absorbs ultraviolet light, meaning much of the light that hits it has no effect.

Bare and Zhang suggested that binding a luminescent compound called ruthenium to titanium dioxide could help increase the spectrum of light that can interact with the material. They designed an experiment to test this. Zhang began the summer by measuring the rates at which titanium dioxide would purify water on its own. But he hit a roadblock when he tried to attach the ruthenium to the semiconductor. The molecules that would make the binding possible were not connecting.

Zhang and Bare experimented with the problem for several weeks. Finally, two weeks ago they made the chemicals bind by changing the acidity of the solution, although the process needs more testing to confirm the success. Zhang looked back at the detour as an effective learning opportunity that helped him understand how to solve problems in original research.

“It’s both a process of learning and researching,” he said. “In the lab, the professor knows everything and can answer all the questions. But in research, there may be a topic that the professor is not very familiar with, and you have to research together.”

Bare added that this is part of the purpose of fostering research opportunities for students who may spend much of their lives solving research problems. “In a research project, we don’t know what’s going to work and what isn’t,” he said. “If it doesn’t work, we have to put our heads together and find out why.”

Student explores more efficient soil remediation options

This summer, Hannah Edwards ’16 is searching for a better way to remove toxins from soil.

She started her summer research by contaminating several containers of soil with lead, an element that is known to cause developmental defects, especially in younger people. Then she started experimenting with plants to see which would best remove through a process called phytoremediation.

“We’re trying to show that phytoremediation is an economically viable option for brownfields and vacant lots in general, but especially in Lynchburg,” she said.

Her quest for a better way to clean soil started during her first year at Randolph when John Abell, an economics professor, took some of his students to visit Lynchburg Grows, an urban farm and nonprofit in Lynchburg. The farm is operated in greenhouses on a former brownfield site that was remediated by removing a significant amount of soil and bringing new soil in.

“There has to be a better way,” Edwards thought.

There is—phytoremediation is an effective way to cleanse soil, and Randolph students and professors have experimented successfully with the process before. However, as Edwards learned more about phytoremediation, she saw a common problem: the plant that is best at removing lead is a type of corn that is not native to Virginia and requires a lot of water to grow.

This led Edwards to propose a project for the Summer Research Program. She wrote her own research proposal and asked professors to advise her on the project this summer. Sarah Sojka, an environmental studies and physics professor, and Kristin Bliss, a biology professor, agreed to help.

Edwards faced some roadblocks in her research. For example, some of the plants she was growing for the tests died. However, she did get a strong population of ragweed for the tests.

She planted the ragweed, as well as corn, in several containers of soil that had various amounts of lead. This week, she harvested the grown plants, dried them, and began processing them with nitric acid to determine the lead content.

Finding a native species that can pull lead from soil but requires less water to grow would help make phytoremediation more feasible, and even economically beneficial. “If you can’t show people that a plan is going to make them money, it doesn’t matter how good it is for the environment, because they’re not going to see it as the best option for them right now,” she said. “You have to be able to give them hard figures.”

Edwards plans to incorporate her findings into a report on how phytoremediation can be used effectively in Lynchburg.

Chemistry professor speaks at regional conference

Bill Mattson, a Randolph College chemistry professor, will present a speech about creative problem solving for a regional chemistry teachers’ conference this week, drawing on ideas he and his students have explored in chemistry classes and research at Randolph.

Bill Mattson talks with Emily Rist ’14 about a modified high-heeled
shoe she invented for one of his classes. Inventing solutions is one
form of creative problem solving he plans to speak about Friday.

The Middle Atlantic Association of Liberal Arts Chemistry Teachers (MAALACT) will begin its annual meeting on Friday, Sept. 28. Mattson will be the plenary speaker that night. His speech is titled “Creative Problem Solving in Chemical Research,” with its main focus being on the creativity he challenges his students to use when they approach problems.

Creative problem solving is featured prominently in Mattson’s courses at Randolph College. For example, his seminar course for first-year students challenges students to solve a problem that bothers them. They start with a “bug list” that names problems that irritate them. “From such a list they often get an idea for an invention—a requirement for the course,” Mattson said.

In his chemistry courses, he challenges students to think about applications that chemistry has outside of the laboratory. “One of the ways one gets ideas is to observe a property that can be applied to something useful,” he said. Mattson’s speech will include an example of this creative process from a class where he placed a marshmallow in a vacuum. In the airless environment, the marshmallow expanded for some time, only to reverse and collapse. Mattson and his students then brainstormed applications for that observation.

They concluded that using a vacuum chamber could help produce polystyrene—a plastic used in products such as egg cartons and disposable cutlery—while using less of a polluting chemical, or to shell peanuts more quickly.

Although his audience this weekend is a group of chemistry teachers who would have interest in the specific chemical applications, Mattson said his speech will mostly emphasize the importance of creative problem solving. “It can certainly apply to people and groups who aren’t chemists,” he said.