Dechlorination of marine iron artifacts using calcined layered double hydroxides

The presence of Cl − is the primary factor responsible for the rapid corrosion of marine iron artifacts, making the efficient dechlorination process a critical challenge for their long-term preservation. We employed calcined Mg/Al layered double hydroxide (LDH) as a dynamic chloride-capturing material to accelerate dechlorination under mildly alkaline conditions. It was shown that calcined MgAl-LDH (LDO) reconstructed through the memory effect and continuously immobilized released Cl − , thereby maintaining a low chloride concentration in the treatment solution and promoting sustained chloride migration from β-FeOOH. Under optimal conditions (pH 9), Cl − was rapidly captured within 24 h via structural reconstruction of LDO, reducing the Cl − content from 4.68% to 1.17% in powdered samples and from 4.93% to 2.86% in simulated β-FeOOH samples. Electrochemical tests showed that after dechlorination, the corrosion current density of the simulated samples was reduced by 67% (from 115.6 μA/cm 2 to 37.44 μA/cm 2 ), and the polarization resistance was increased 2.8 times (from 936 Ω·cm 2 to 3520 Ω·cm 2 ), demonstrating significantly enhanced corrosion resistance. The proposed approach achieves highly efficient dechlorination of marine iron artifacts, providing a promising strategy for their long-term preservation.