Alfred University undergraduates research use of waste glass in promoting plant growth

William LaCourse (right), emeritus professor of glass science in Alfred University's Inamori School of Engineering, looks over some pellets made from powdered waste glass created by junior ceramic engineering major Brenton Gagliardo. The pellets are designed to hold water and, as they break down, release nutrients beneficial to plants into soil.

A group of four undergraduate engineering students at Alfred University, led by William LaCourse, emeritus professor of glass science, are studying ways that waste glass material can be used to fortify soil with the minerals needed to sustain plant growth. The research could provide a path to significantly reduce the stream of waste entering landfills while reinvigorating soil devoid of nutrients.

The students participated in the Imanori School of Engineering's second annual Summer Research Institute, which facilitated a number of research projects in engineering. More than 40 undergraduate and graduate students spent the summer conducting research on projects guided by 12 faculty.

The Institute is sponsored by the Center for Advanced Ceramic Technology (CACT) at Alfred University, the New York State Foundation for Science, Technology, and Innovation (NYSTAR), Corning Inc., Owens-Corning, Washington Mills, the Western New York Section of the American Ceramic Society (ACerS), MosSci, Cany, and donors Bill Rice '78 and Richard Block '62.

The study of the use of waste glass in plant fertilizer began during the spring 2024 semester, with four engineering students-Livia Simon, Alex Jonsson, and Andrew Parnapy, who will be seniors this fall, and junior-to-be Brenton Gagliardo-advised by LaCourse. The research is supported by grant funding the University received from the New York State Department of Environmental Conservation to study ways to recycle and reuse waste glass material.

LaCourse said there are significant areas of land in the United States (some 200 million acres) that have lost the ability-because of over-farming, or the presence of heavy industry, for example-to provide the nutrients needed for plant growth. The goal of his students' research is to promote the "remineralization" of soil using waste glass as the major ingredient. Silica, a mineral found in sand, is the major component used in the production of glass and when used in soils, chemical reactions of soils containing waste glass produces silicic acid, which is not only beneficial to plant growth, but also protects plants from harm caused by factors such as insects, dry spells, and bacterial threats.

"We want to develop a series of 'waste glass based' re-mineralized soils that are capable of providing the needed nutrients, together with silicic acid, for a wide range of crop types," LaCourse commented. "We know silica is an extremely important mineral but is also extremely difficult to make available to plants. Waste glass has an almost magical effect in that it not only supplies 'plant available silica' and several other needed nutrients, it also initiates in-soil chemical reactions that help other remineralization additives release their nutrients."

Simon, Jonsson, Parnapy, and Gagliardo spent the summer conducting experiments and analyzing data to test the hypothesis that waste glass can be used as an effective fertilizer ingredient.

Jonsson, a dual major in ceramic engineering and art from South Windsor, CT, performed tests using ion exchange, the same process Corning Inc. scientists employed in the development of the Gorilla Glass used on smart phone screens. That process involves using heat to partially melt glass and immersing the glass in a bath of liquid potassium nitrate, which causes sodium (detrimental to plant growth) to be replaced with potassium (beneficial to plant growth). By removing the sodium and replacing with potassium, the salinity of the soil is decreased making it significantly more suitable for plant growth.

Alfred University seniors Alex Jonsson (left), an art and ceramic engineering major, and Andrew Parnapy, a biochemistry major, look over some data on a laptop as part of the experimental research their group conducted during the Summer Undergraduate Research Institute.

"We want to change the composition of the glass, so it's most beneficial to plant growth," Jonsson said. He added that because the ion exchange process does not involve a full melt of the glass-400 to 600 degrees centigrade; as opposed to the 1,200-1,500 centigrade required for a full melt-the process has a smaller carbon footprint. "It's a way of changing the (glass) composition without needing a full melt, so it's much more cost effective and energy efficient."

"Our goal is to take soil that has been stripped of its nutrients and reinvigorating it," Parnapy added. "Silica and silicic acids help with the remediation by making phosphorous available to plants."

Parnapy, a biochemistry major from Byron, NY, spent much of the summer conducting data analysis on the team's experimental research-using technologies like infrared spectroscopy, and x-ray diffraction-to learn, among other things, how glass breaks down in water, and how to speed up the process of dissolution of minerals contained in the silica by introducing materials such as potassium hydroxide. "The data tells us what materials are coming out of the silicic acid, which goes into the plant and is absorbed into the cell structure," he said.

Silica-fortified soil will help plants grow stronger and be more resistant to pests and the negative effects of ultraviolet light exposure and metal toxicity, noted Simon, a biomaterials engineering major from Andover, NY. "It adds an extra layer of protection for the plants." She conducted dissolution experiments using water and waste glass, measuring the changes in pH over time.

"As I'm getting the pH data, Andrew and I work together to analyze the glass material," she said. "The chemistry can be a challenge. Silicon is not very soluble, so it takes time to build up the materials" to analyze.

Gagliardo's work included melting waste glass to liquid and pouring it into water to create strands of glass which when broken can be turned into powder. The powder is then placed in crucibles and heated to 700 degrees Centigrade. The material is used to make porous pellets, which absorb and hold water, "breaking down the glass from the inside."

He explained that the pellets can be used in areas where rainfall is sparse. Placed in the soil, the pellets will hold rainwater, which will dissolve the glass and release the beneficial plant nutrients slowly.

The students are excited about the research in part because of the environmental benefits that could result from it, which dovetails with the School of Engineering's mission of promoting sustainability.

"If this proves viable, you could potentially divert a significant portion of glass into fertilizer and away from the waste stream," Jonsson commented.

"It's a way of removing glass from landfills," added Gagliardo, a ceramic engineering major from Portville, NY. "This will be very beneficial to the environment."

Jonsson noted that despite none of his fellow student researchers being glass science majors, Alfred University allows them the unique opportunity to work in the glass space, in this case for the good of the environment.

"When you think about the impact this could have, no matter how removed you are from the environment in your work you are still doing something to decrease the carbon footprint and improve the environment," Jonsson said. "That's the beautiful thing about this department and this school."