He’s team demonstrates carbon dioxide capture using fruit peels

Teaching Assistant Professor Jiajun He and several members of his research team recently published work from their ongoing porous carbon study in Separation and Purification Technology. 

“We demonstrate a universal production method [for porous carbon] from fruit peel waste as well as the performance of the final material for carbon dioxide capture,” He said. The publication comes in the wake of He’s first-place finish in the Microtrac Scientific Challenge. 

Mechanical engineering graduate students Ho Kun Woo, Pranto Karua, and Wei Zheng, postdoctoral researcher Md Salauddin, and MechSE assistant professor Lili Cai coauthored the article alongside He and first author and second-year PhD student Sadman Sakib.

“I became interested in porous carbon materials because of their unique ability to be engineered from low-cost and renewable biomass sources while offering exceptional surface areas and tunable pore structures,” Sakib said. “The idea that waste materials, like fruit peels, can be transformed into high-performance adsorbents for energy applications was especially motivating to me.”

The team’s paper addresses two sustainability challenges. First, their efforts to convert fruit peels into porous carbon aids food waste management, with global food waste now on the order of more than one billion tons annually. Fruit and vegetable waste account for more than 50 percent of this total, making fruit peels a readily available source material.

Second, materials that can capture carbon dioxide are a valuable resource for scrubbing emissions—for example, from post-combustion processes in power plants.

“If we can trap carbon dioxide emissions from power plants, then later on we can use that carbon dioxide for different purposes,” He explained.

To prepare samples for experimentation, the team first dried fresh peels and ground them into powder. They then processed the powder in a hydrothermal reactor at a controlled temperature to remove certain carbohydrate content, then subjected it to pyrolysis to create the porous carbon framework. Through controlled chemical activation, the team created more pores in the material, resulting in a framework with a very high surface area—roughly 1,000 square meters of surface area per 1 gram of material.

“We created that surface area and fine-tuned the pore sizes and surface chemical groups to enhance [the material’s] interaction with carbon dioxide gas,” He said, noting that they could control pore size by manipulating reaction conditions and concentration. “We performed pyrolysis at 500, 600, 700, and 800 degrees Celsius and observed trends in the pore sizes and surface areas of the final product.”

Based on carbohydrate content, some peels are more suitable for this process than others. The team experimented with orange, mandarin, pomelo, and banana peels—of these, pomelo-derived carbon achieved the strongest carbon dioxide adsorption capacity.

“By systematically comparing four different biomass precursors under identical synthesis conditions, we were able to clarify how precursor chemistry influences pore development and adsorption behavior,” Sakib said.

The team tested their powders under ten cycles of capturing and releasing carbon dioxide, observing a minimal performance change after the tenth cycle.

“For large-scale applications, we need more than ten cycles,” He said of focusing on scaling their efforts in ongoing work. Another consideration to address is the efficacy of the peels for source material as they break down over time.

“We haven’t [yet] tested the different [decomposition] stages of the peels in terms of a precursor for making our material,” He said. “I think that would be a very interesting study later on—because different types of carbohydrates decompose at different rates, the fresh peel may not actually be the ideal precursor. It’s possible that some stage within the decomposition process would give us the best precursor for porous carbon.”

The team’s findings signify advancement for both the development of sustainable carbon capture materials and new opportunities for broader gas-storage applications.

“The most significant part of our work is demonstrating that simple and scalable processing of common biowaste can produce activated carbons with competitive carbon dioxide capture performance at conditions relevant to post-combustion applications,” Sakib said.