Calcium alginate beads derived from brown algae are model polymers to engage students on sustainable solutions to petroleum-based plastics. Finding alternatives to these non-biodegradable polymers are needed to reduce their environmental impact. Companies, such as the Skipping Rocks Laboratory, are mitigating plastic pollution by developing edible packaging and biodegradable coating commercial products. In K-12 classrooms, students can emulate these consumer products by synthesizing calcium alginate beads. Teaching experiments centered on calcium alginate provide ample educational opportunities to learn about chemical bonding, polymers, and sustainability. Herein, we present results of a teaching experiment investigating the synthesis and shape modification of calcium alginate beads by adjusting pH. A multitude of sodium alginate solutions at different pH were prepared using varying concentrations of citric acid. These solutions were subsequently dispensed into aqueous calcium lactate baths to synthesize the beads. Observations were made on bead formation and the effect pH had on its structural integrity. After establishing a relationship between bead shape and pH, alginate solutions in acidic juice beverages were explored. Highlights of this experiment involve its ability to be implemented in a classroom or at home with the safe usage of food grade reagents. Learning outcomes include acid-base reactions, ionic bonding, and green chemistry concepts. A survey of results and critique of the experiment will be shared.

Student investigations in the effect of pH on calcium alginate polymer beads

Fall 2022 abstracts, posters, and presentations will launch in mid-September.

ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.