Researchers at James Cook University have developed a process to synthesize graphene from tangerine peel oil, which they then used to recover silver from waste PV material. To demonstrate the quality of the recovered silver and synthesized graphene, they created a dopamine sensor that reportedly outperformed reference devices.
A team from Australia’s James Cook University has synthesized “free-standing” graphene using non-toxic and renewable tangerine peel oil that can reportedly be used for the recovery of silver from end-of-life organic PV devices.
“Not only did it result in high-quality graphene, but it also demonstrated a remarkable ability to selectively recover silver from photovoltaic waste. One of the most surprising findings was how exceptionally selective graphene was at attacking silver,” said corresponding author Mohan Jacob pv magazine.
The quality of both the recovered and synthesized materials was then demonstrated in a silver-enhanced SPE dopamine sensor device, which outperformed two reference dopamine sensors made without the silver graphene composite
Graphene synthesis
The team began the research by synthesizing graphene “using downstream microwave plasma” under atmospheric conditions. “The key components of the system include a 2.45 GHz microwave generator, a matching network, a cooling system and a reaction chamber,” the report said.
A Raman spectrum analysis of the graphene showed “a characteristic 2D peak” at microwave powers between 200 W and 1000 W. “The transmission electron microscopy images revealed an interstitial distance of 0.34, which corresponded to the value of X-ray diffraction calculated according to the Bragg’s law. ”, the team said.
Silver recovery from PV
The team then extracted silver from organic PV devices via leaching in a nitric acid solution. The PV coating contained indium tin oxide (ITO), zinc oxide (ZnO), molybdenum oxide (MoO3) and silver (Ag).
After leaching was completed, the solution was cooled and used as a stock solution to create a graphene-coated SPE. “After 10 minutes of electrodeposition, the Ag concentration decreased slightly to 1.69 ppm. This decrease suggests that some Ag ions were reduced and deposited on the electrode surface during the electrochemical process. After 20 minutes of electrodeposition, the Ag ion concentration further decreased to 1.62 ppm, indicating a continued decrease in Ag ion concentration,” the academics said.
“These results suggest that a longer duration of electrodeposition may lead to a further reduction in silver concentration.” The Ag deposition was confirmed by cyclic voltammetric detection.
“Despite the presence of several other compounds in the PV waste solution, graphene showed an extraordinary ability to isolate and recover silver with high precision. This dual benefit of producing valuable graphene and selectively recovering silver from a complex mixture was an exciting and somewhat unexpected outcome,” said Mohan.
The team said the study highlights “the remarkable effectiveness” of graphene in recovering valuable metals such as silver from electronic waste.
“We chose to demonstrate with waste PV material because photovoltaic waste is a rapidly growing problem due to the increasing adoption of solar energy. The disposal of PV panels, which contain valuable metals such as silver, poses both environmental and economic challenges. By focusing on PV waste, we wanted to develop a sustainable solution that meets the urgent need for effective recycling methods while recovering valuable resources,” said Jacob.
Dopamine sensor demonstration
To illustrate the quality of the composite material in a real-world application, the team created a graphene-silver electrode (SPE/graphene-Ag) detector and compared it to a bare SPE detector and a graphene/SPE detector. Test results showed that the SPE/graphene-Ag electrode showed a “significant improvement in peak current” compared to the other two specimens.
Other applications of graphene-silver composites were proposed by the researchers, such as corrosion-resistant coatings, conductive inks to use flexible devices in the electronics industry, antimicrobial coatings for use in the biomedical industry, as well as sensors to detect gases, biomolecules and other substances. pollutants.
Their work is described in detail in the article “Green synthesis of graphene for targeted recovery of silver from photovoltaic waste,” published in Chemosphere.
The responses to the research so far have been positive. “Our work has just come online and we are overwhelmed by the response from our colleagues and their interest in our research,” says Jacob, adding that the group has received encouraging feedback about the “wider applicability and potential impact” of the work in our research. in the field of battery and electronics waste.
The next steps for the team are to optimize the green synthesis process to improve its scalability and economic viability, aiming for a process that can be integrated into existing PV recycling and e-waste infrastructure. “We are actively looking at commercialization to bring these developments to market and have a significant impact on the industry,” said Jacob. “We are also exploring partnerships with industry stakeholders and investors to test large-scale deployments.”
This content is copyrighted and may not be reused. If you would like to collaborate with us and reuse some of our content, please contact: editors@pv-magazine.com.
Popular content
