Five students from the Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Negeri Yogyakarta (UNY) have successfully developed an environmentally friendly photocatalyst innovation based on Cu₂O/CuO@TiO₂ nanocomposites by utilizing waste copper cables and lime peels. The innovation was developed through the Student Creativity Program in Exact Sciences Research (PKM-RE) as an effort to provide a sustainable solution to pollution caused by textile and batik industrial wastewater.

The PKM-RE team is led by Ria Amelia (Physics Undergraduate Program, Class of 2023), with members Martin Imanuel Panjaitan (Physics, 2024), Sekar Samuso Jati (Physics, 2023), Nandari Ainandita (Chemistry, 2023), and Isnaini Laila Azizah (Biology, 2023). The research is supervised by Riza Ariyani Nur Khasanah, S.Pd., M.Sc., Ph.D., a lecturer in the Department of Physics, FMIPA UNY.

The research, entitled "Engineering Cu₂O/CuO@TiO₂ Nanocomposites from Copper Cable Waste Using Lime Peel Extract for the Photodegradation of Batik Dye Waste," utilizes discarded copper cables as a source of copper ions, while lime peel extract serves as a natural reducing agent during the synthesis of the photocatalytic material.

One of the study's key innovations lies in its application of the green synthesis concept by simultaneously utilizing two types of waste: electronic waste and organic waste. Lime peels, collected from leftover materials generated by small and medium-sized food businesses around the UNY Food Court, contain polyphenol compounds that function as natural reducing and stabilizing agents in the formation of Cu₂O/CuO nanoparticles. Meanwhile, discarded copper cables are transformed into high-value raw materials for producing photocatalytic nanocomposites.

The photocatalytic material was designed to exhibit high activity under visible light, enabling it to effectively degrade methyl orange, one of the synthetic dyes commonly found in textile and batik industry wastewater. Through the photodegradation process, the dye molecules are broken down into simpler, less harmful compounds, making them safer for the environment.

In addition to addressing industrial dye pollution, the innovation supports the implementation of the circular economy by converting waste materials into high-value functional products. The project demonstrates that materials traditionally regarded as waste can be transformed into innovative technologies that contribute to environmental sustainability.

According to Ria Amelia, the team leader, the research is expected to become an alternative environmentally friendly wastewater treatment technology while raising public awareness of the importance of viewing waste as a valuable resource with both economic and environmental benefits.

"We hope this research can serve as an alternative green technology for wastewater treatment while encouraging the public to recognize that waste can be transformed into valuable resources with significant environmental and economic potential," she said.

The team also actively documents the progress of the research through its Instagram account, @pkmre_cucitrox, where the public can follow every stage of the project—from waste collection and material synthesis to photocatalyst testing and evaluation.

This research supports several Sustainable Development Goals (SDGs), particularly: SDG 4 – Quality Education SDG 9 – Industry, Innovation and Infrastructure SDG 12 – Responsible Consumption and Production

By transforming electronic and organic waste into advanced photocatalytic materials, the project demonstrates how interdisciplinary scientific research can contribute to environmental protection, sustainable industrial practices, and the advancement of green technology.