Acid-responsive MSN@RBA enhanced coating wound healing through alerting and releasing repairing agents

Acid mine drainage (AMD) is a persistent and challenging environmental pollution problem. The consequences of AMD include soil pollution, biodiversity loss, and ecosystem collapse. Our study found that rhodamine B acylhydrazone (RBA) exhibits high sensitivity to Fe3+ and can be used as a corrosion inhibitor. This finding led us to hypothesize that the application of RBA is an effective strategy for constructing self-warning and self-healing integrated pH-responsive mercaptopropyl trimethoxysilane (PeopS-SH) coatings. We herein successfully prepared RBA-loaded mesoporous silica nanoparticles (MSN@RBA) designed to exhibit localized, acid-responsive behavior to avoid oxidation site diffusion and enhance wound healing. These MSN@RBA were sensitive to acidic environments, triggering the rapid release of RBA. The experiments showed that MSN@RBA effectively inhibited the oxidation rate of pyrite and enhanced the long-term passivation effect of the coating. Our findings further demonstrated that MSN@RBA reduced the corrosion current density (0.17 μA cm−2), increased the corrosion potential (335 mV), and improved the thickness and density of the coating. The results of release experiments, electrochemical tests and chemical leaching indicate that MSN@RBA releases RBA in acidic environments, and its spironolactam structure opens and forms a complex with Fe3+. The damaged site is fluorescently labeled and repaired. In conclusion, this acid-responsive nanoparticle system presents a new strategy for the treatment of tailings in harsh environments for a long time.