Producing Magnesium Hydroxide Coating from Seawater to Prevent Hydrogen Sulfide-induced Corrosion in Concrete

The anaerobic nature of concrete structures in sewage, industrial, and agricultural sectors result in the proliferation of sulfate-reducing bacteria. These bacteria release hydrogen sulfide through sulfate reduction processes, rendering the exposed concrete structure to hydrogen sulfide-induced corrosion. While commercial magnesium hydroxide coatings (Mg(OH)_2) are being used as a conventional method, this study explored using seawater-derived Mg(OH)_2 as an alternative sustainable protective coating. Three set-ups were tested: uncoated concrete, seawater-derived Mg(OH)_2 coated concrete, and commercially available Mg(OH)_2 coated concrete. Each setup had four replicates and was exposed to 4M sulfuric acid for four days. To evaluate the coating's effectiveness, the compressive strength of the specimens was assessed. The tests revealed that seawater-derived Mg(OH)_2 coated specimens did not outperform those coated with commercially available Mg(OH)_2. However, they demonstrated superior performance compared to the uncoated specimens. Overall, this highlighted the potential of seawater-derived Mg(OH)_2 as a sustainable alternative for mitigating hydrogen sulfide-induced corrosion.