Plant Secondary Metabolites in Action: A Green Chemistry Project-Based Module to Enhance Environmental Literacy in Middle School

To integrate green chemistry principles into middle school science education and enhance environmental literacy, we developed a project-based learning module centered on the extraction and application of plant secondary metabolites (PSMs). Using readily available kitchen and campus waste, including pomelo peel, Sapindus shells, spent coffee grounds, and maple leaves, students carried out three sequential, hands-on experiments: (i) steam-distillation of pomelo peel to obtain essential oil and hydrosol; (ii) preparation of a Sapindus-pomelo peel composite cleaner; and (iii) natural dyeing of wool fabric with coffee grounds and maple-leaf thermal transfer printing. Through these activities, students engaged in an inquiry-based learning cycle while exploring key chemical concepts such as distillation, surfactant behavior, and mordant-based dye fixation. Pre- and post-test assessments (n = 37) revealed statistically significant improvements in students’ environmental knowledge, attitudes, and self-reported pro-environmental behaviors (p < 0.01). Follow-up interviews (n = 15) further indicated enhanced engagement, practical skills, and awareness of sustainable practices. Designed with an emphasis on safety, low cost, and material accessibility, this module is accompanied by a teacher’s guide and assessment tools. It offers a transferable pedagogical model for integrating green chemistry and environmental literacy into middle school chemistry, biology, and cross-disciplinary curricula, especially in contexts that prioritize hands-on learning and sustainability.