Integrating Advanced Research Methods into Teaching Practice: Optimization of Water Caltrop Shell Extract Yield as a Green Corrosion Inhibitor Based on Response Surface Methodology

Abstract Traditional laboratory teaching often relies heavily on confirmatory experiments, which may provide limited opportunities for students to practice experimental design, data interpretation, and model-based decision-making. Building on our group’s prior work, we designed a research-oriented laboratory experiment applicable to upper-division undergraduate and graduate instruction. In this module, response surface methodology (RSM), including Box–Behnken design-based quadratic modeling, ANOVA, and response surface analysis, was applied to optimize the extraction yield of water caltrop shell extract as a green corrosion inhibitor. The model-derived optimum was approximately 50 °C, 60 min, 60% ethanol (v/v), and 27 mL/g, and practical classroom validation was conducted at 50 °C, 60 min, 60% ethanol (v/v), and 30 mL/g. Through experimental design, extraction operation, statistical analysis, and model validation, the module helps students connect hands-on experimentation with quantitative reasoning. Overall, this activity provides a practical example of integrating research-based optimization, green chemistry, and data-driven decision-making into advanced laboratory teaching.