Ecotoxicological evaluatioin of biological corrosion inhibitors Sodium Glutamate (SG) and Glutamic Acid (GA) in their free forms and layered double hydroxide (LDH) nanoencapsulated

Abstract

The metallic corrosion process is one of the main causes on the degradation of environmental marine equipment and structures. This problem has been minimized by the addition of coatings containing chemistry inhibitors, delaying the corrosion process. However, due to its toxicity and environmental regulations, there is an interest on replacing these compounds by effective and less toxic alternatives. Recently, biological based molecules, as Sodium Gluconate (SG) and Glutamic Acid (GA), have been showed as environment friendly compounds. Although, the biological corrosion inhibitors (bio-CI) do not show an anticorrosion efficacy on marine steel comparing to the traditional CI. University of Aveiro's researchers, in Portugal, in addition with a private company (Smallmatek Ltda.), developed manufactured nanomaterials (MN) made up with layered double hydroxide (LDH) to immobilize/encapsulate the bio-CI, aiming to increase their anticorrosion efficacy, because it can control their release in reason of the physical-chemical changes on sea water. In this project the ecotoxicological evaluation of the biological corrosion inhibitors SG and GA, in their free and nonencapsulated ways, will be done over five different neotropical marine species in different trophic levels. Will be conducted embryo larval development essays with sand dollar (Mellita quinquiesperforata) and mussel (Perna perna); and fecundity essays with copepods (Nitocra sp.), aiming to stablish the bio-CI toxicity levels, through endpoints like growth and development inhibition. A preliminary estimation of associated hazard will be done with the CI and their compounds, from the PNEC (Predicted N0-Effect Concentration) calulation to each species/test. Alhough, the generated data in this masters project will be used in an international project (NANOGREEN) to generated species sensitivity distribution curves (SSD curves) aiming to stablish strong PNECs. This study will contribute to the development of anticorrosive additives with high performances with a previous hazard evaluation and evironmental hazard, giving information about effects in neotropical species.