New Perspectives in Science Education

The removal of pollutants from wastewater is a task that is tackled by many different processes in wastewater treatment plants. If conventional mechanical and biological treatment processes are not sufficient to break down persistent organic pollutants such as the drug diclophenac, for example, other methods such as oxidative degradation using ozone and ultraviolet radiation are used [1,2]. Another degradation option is the Fenton reaction or its modification: the electro-Fenton reaction, which describes the catalytic decomposition of in-situ generated hydrogen peroxide to highly reactive radicals, capable of subsequently decomposing organic molecules [3,4].

In addition to a brief explanation of the electro-Fenton reaction itself, a series of experiments are presented to integrate this interesting and topical phenomenon into chemistry classes [4]. This proposed inquiry-based lesson is designed in a way to allow the students to investigate the individual steps of the electro-Fenton reaction as independently as possible. After each experiment, they should develop interpretations and experimentally verifiable hypotheses based on the observations made to design the following experiment.

In order to determine the extent to which the students develop these conclusions independently and where help from the instructor is necessary, the series of experiments was carried out with a group of students in the XLAB student laboratory while documenting the classroom discussions. During this structured lesson observation, particular attention was paid to the interpretation of the observations with regard to the investigation of individual steps of the electro-Fenton reaction. The resulting findings are supplemented by a short questionnaire, which was employed at the end of the teaching unit and aimed at measuring the acquired subject knowledge and the general opinion about the interest and the difficulty in the experiments.

[1] Rodríguez, A. et al. (2008). Ozone-Based Technologies in Water and Wastewater Treatment. In: Barceló, D., Petrovic, M. (eds) Emerging Contaminants from Industrial and Municipal Waste. The Handbook of Environmental Chemistry, vol 5. Springer, Berlin, Heidelberg.

[2] Iervolino, G., Zammit, I., Vaiano, V., Rizzo, L. (2020). Limitations and Prospects for Wastewater Treatment by UV and Visible-Light-Active Heterogeneous Photocatalysis: A Critical Review. In: Muñoz-Batista, M., Navarrete Muñoz, A., Luque, R. (eds) Heterogeneous Photocatalysis. Topics in Current Chemistry Collections. Springer, Cham.

[3] Barbusinski, K. (2009). Henry John Horstman Fenton: Short Biography and Brief History of Fenton Reagent Discovery. Metrologia, 14(1-2), 101-105.

[4] Lanfermann, P., Weidmann, C., Waitz, T. (2024). The Electro-Fenton Reaction in Chemistry Class. CHEMKON, 31(6), 226-231.