resumo
Metal corrosion is a colossal technical, economic, and environmental challenge worldwide. Protective coatings containing corrosion inhibitors (CIs) are commonly used to address this natural process, particularly severe in immersed structures in seawater. However, high-performance CIs, such as benzotriazole (BTA), often exhibit toxicity towards aquatic organisms and leach prematurely. This study introduces safe and sustainable-by-design engineered nanomaterials, specifically layered double hydroxides loaded with BTA (Mg-Al LDH-BTA and Zn-Al LDH-BTA), as an innovative and eco-friendly approach compared to state-of-the-art CIs. This study aims to characterize both nanomaterials, assess their anti-corrosion performance when incorporated in polyurethane coatings, and evaluate their environmental behavior when dispersed in water, short-term acute and chronic effects on temperate marine species, and the environmental hazard. Key findings include a superior anti-corrosion performance of coatings containing Zn-Al LDH-BTA compared to BTA-coatings. Aqueous dispersions of nanomaterials exhibit instability of particle size and zeta potential over time, while concentrations of metals (Al, Zn) and nitrates reach high levels in the highest tested concentration due to partial dissolution, which may explain the observed toxicity patterns (median effect concentrations in the mg L-1 range). The tested compounds were not toxic for most tested species, apart from bacteria (Aliivibrio fischeri) and/or echinoderms (Paracentrotus lividus) and, in case of Mg-Al LDH-BTA, also on two microalgae species. The highest statistical PNEC value was observed for Mg-Al LDH-BTA (PNEC = 0.326 mg BTA per L), while the highest deterministic PNEC value was found for Zn-Al LDH-BTA (PNEC = 0.00041 mg BTA per L). These findings indicate that both nanomaterials are environmentally sound and efficient alternatives for anti-corrosion maritime applications.
palavras-chave
ACTIVE CORROSION PROTECTION; SMART COATINGS; ALUMINUM; TOXICITY; ECOTOXICITY; INHIBITION; STEEL
categoria
Chemistry; Environmental Sciences & Ecology; Science & Technology - Other Topics
autores
Figueiredo, J; Perina, F; Carneiro, D; Iqbal, MA; Oliveira, T; Rocha, C; Maia, F; Tedim, J; Martins, R
nossos autores
João Tedim
Professor Associado com Agregação
Roberto Carlos Domingues Martins
Bolseiro de pós-DoutoramentoProjectos
Collaboratory for Emerging Technologies, CoLab (EMERGING TECHNOLOGIES)
CICECO - Aveiro Institute of Materials (UIDB/50011/2020)
CICECO - Aveiro Institute of Materials (UIDP/50011/2020)
Associated Laboratory CICECO-Aveiro Institute of Materials (LA/P/0006/2020)
agradecimentos
This work was developed in the scope of the NANOGREEN project "Towards a new generation of sustainable nano-based additives for maritime anti-corrosion smart coatings: a multidisciplinary framework within the Atlantic" (CIRCNA/BRB/0291/2019; DOI: 10.54499/CIRCNA/BRB/0291/2019) funded by national funds (OE), through the Portuguese Foundation for Science and Technology, I.P. (FCT). Thanks are also due to FCT for the financial support through national funds to CESAM - Centre for Environmental and Marine Studies (UID/50006 + LA/P/0094/2020) and CICECO - Aveiro Institute of Materials (UIDB/50011/2020, UIDP/50011/2020 & LA/P/0006/2020). R. Martins was hired under the Scientific Employment Stimulus - Individual Call funded by national funds (OE), through FCT (2021.00386.CEECIND/CP1659/CT0011, DOI: 10.54499/2021.00386.CEECIND/CP1659/CT0011). J. Figueiredo and F. Perina were awarded with a grant (BI/UI88/8183/2023) and a researcher contract through the research project NANOGREEN (CIRCNA/BRB/0291/2019).