New research from Northwestern University has found that a mild zap of electricity can strengthen marine coastlines for generations, reducing erosion in the face of climate change and rising sea levels. The study was inspired by shell-dwelling sea life, which use dissolved minerals in seawater to build their shells. Researchers used a mild electrical current to transform sea-soaked grains of sand into a rock-like solid, offering a lasting, inexpensive, and sustainable solution for strengthening global coastlines. The study, led by Alessandro Rotta Loria, will be published in the journal Communications Earth and the Environment.
Climate change has caused conditions that are eroding coastlines, with 26% of Earth’s beaches expected to be washed away by the end of the century. Current approaches to mitigating erosion, such as building protection structures and injecting cement into the ground, are expensive and not long-lasting. Sea walls also suffer from erosion, with sand beneath them eroding over time. The use of big stones and injection of binders into the ground are costly and have irreversible environmental drawbacks. The new technique developed by Rotta Loria and his team offers a simpler, more eco-friendly solution inspired by coral and mollusks.
Applying a mild electrical current to seawater triggers chemical reactions that convert dissolved minerals into solid calcium carbonate or magnesium hydroxide. These minerals act as a glue, binding sand particles together, making the sand look like a rock that is strong and solid. The process is effective with different types of sands and results in a durable material that protects coastlines and property. The process is also reversible, as the electricity can dissolve the minerals if the solidified sand needs to be removed. The cost of the new technique is significantly less than comparable methods using binders, making it a competitive and cost-effective option for coastal protection.
The process offers a range of applications beyond coastal protection, such as strengthening seabeds beneath sea walls, stabilizing sand dunes, and repairing cracked structures made of reinforced concrete. The reversible nature of the technique allows for easy removal if needed and can heal potentially destructive cracks with a single pulse of electricity. The research team plans to test the technique outside of the laboratory and on the beach to further evaluate its effectiveness and practical applications. Supported by the Army Research Office and Northwestern’s Center for Engineering Sustainability and Resilience, the study showcases the potential for the new technique to revolutionize coastal protection efforts worldwide.
