MIL-101(Cr)/epoxy composite coating for enhanced corrosion resistance in concrete sewer infrastructure
Sagor Kumar Pramanik, Muhammed A. Bhuiyan, Dilan Robert, Rajeev Roychand, Li Gao, Biplob Kumar Pramanik
Abstract
Concrete sewer systems are essential to urban infrastructure but are highly susceptible to microbial-induced corrosion (MIC), leading to severe structural degradation and substantial maintenance costs. This study develops a MIL-101(Cr)/epoxy composite coating to mitigate MIC and enhance concrete durability in aggressive environments. MIL-101(Cr) nanoparticles were synthesized via a scalable hydrothermal process and incorporated into epoxy matrices at varying concentrations (0.5%, 1.0%, and 1.5% by weight). The optimized 1 wt% MIL-101(Cr)/epoxy composite exhibited remarkable corrosion resistance, reducing weight loss to 5.2% after 65 days of sulfuric acid exposure, improving performance by 78.3% over uncoated concrete and 70.6% over pure epoxy coatings. Water absorption was minimized to 0.12%, ensuring superior moisture resistance and long-term durability. The composite coating achieved a pull-off strength of 6.12 MPa, a 48.5% enhancement over conventional epoxy coatings, highlighting its strong adhesion and structural integrity. Thermogravimetric analysis showed improved thermal stability, with dehydration peaking at 173.6 °C. Density Functional Theory (DFT) calculations further validated the experimental findings, demonstrating enhanced electron-donating and electron-accepting properties that contribute to the composite’s outstanding anti-corrosive performance. This study demonstrates that MIL-101(Cr)/epoxy composites are a promising and sustainable solution for extending the service life of concrete sewer infrastructure in corrosive environments.