Ecotoxicological evaluation of free and nanoestructured in layered double hydroxide (LDH) biological corrosion inhibitors (bio-CI) in Mytilus galloprovincialis and Hediste diversicolor and the bio-IC release study from the nanoestructures over time

Abstract

The metallic corrosion process is the main cause of estructure and equipament degradation in the marine environment. This issue has been minimized by the addition of chemycal inhibitor coats, delaying the corrosion process. Although, the corrosion inhibitors (CI) available in the Market are toxic to the biota, so there is an interest in replacing these compounds to more effective and less toxic alternatives. Recently, biological based corrosion inhibitors (bio-CI) have been shown as environment friendly alternatives. Otherwise, the biological based additives, like the conventional CI, are rapidly leached from the maritime paints, early loosing their anticorrosion efficacy. Reserarchers from University of Aveiro (UA), in Portugal, alongside with a company (Smallmatek LDA), developed manufactured nanomaterials (NM) made of layered double hydroxides (LDH) to imobilize the bio-IC, aiming to rise the anticorrosion efficency of these substances, because the controlled release of the bio-IC happens when alterations promoted in the environment due to the sea water physical-chemical changes. In this way, this presente project aim to evaluate the bio-IC liberation index from the nanoestructures (LDH) in different physical-chemical conditions, and also evaluate the ecotoxicological effects of two different bio-IC, sodium gluconate (SG) and nitrite (NO2), in their free and nanoestructured forms (LDH-SG and LDH-NO2), using temperate marine species of the bivalve Mytilus galloprovincialis and the polichaete Hediste diversicolor, with different fisiological endpoints (filtration index, condition index and air survival) and biochemical biomarkers (lipidic peroxidation, catalases, gluthatione-S-transferase and acetylcholinesterase), alowing to answer environmental hazard questions for temperate species (evaluated in this BEPE) and compare the datas with subtropical species (evaluated in my master's thesis). This study will also contribute to environmently validate a new generation of high performance anticorrosion additives.