DEVELOPMENT OF BIODEGRADABLE CHEMICAL PRODUCTS FOR PROTECTION OF CORROSION ON CARBON STELL AISI 1018 AND OF METAL DETERIORATION CAUSED BY FUELS
Biodegradable corrosion inhibitors; surfactant; microemulsion; additive biofuel; clean technology
Few decades ago pollutant agents were seen as an inevitable consequence of technological progress. However, due to the exacerbate degradation of global environment, new practices were adopted in order to control environmental impacts, which includes development of clean technologies. In this sense, less aggressive products is a sustainable alternative for controlling metal deterioration. The aim of this present study was to evaluate the efficacy of biodegradable surfactants, sodium dodecylbenzene sulfonate (SDBS) and saponified coconut oil (OCS) loaded in a microemulsion system (MES) as corrosion inhibitors on carbon steel AISI 1018 in saline medium (NaCl 0.5%). The tested samples (SDBS-AS, SDBS-ME and SDBS-MES-OCS) were evaluated by Galvanostatic and Linear Polarization Resistance (LPR) methods, as well as Weight Loss (WL), showing maximum anticorrosion efficiencies ranging from 70.4% to 77.6%. The surfactants SDBS was solubilized in aqueous solution (SDBS-AS) or loaded on colloidal system such as: SDBS on microemulsion system (SDBS-ME) containing 30% of S/C [15% of SDBS, as surfactant (S), and 15% of butan-1-o, as co-surfactant), 10% of oil phase and 60% of water], and also SDBS mixed with OCS (saponified coconut oil, a semi-synthetic surfactant) on microemulsion system so called SDBS-MES-OCS), containing 30% S/C [1% of SDBS and 99% of OCS, 10% of oil and 60% of water). Comparatively, it was also studied the metal deterioration caused by fuels for diesel, a B7 mixture (B7-OS with 93% of diesel S10 and 7% of biodiesel) and B7-AD (additive biodiesel). The biodiesel was obtained from soybean oil (named B7-OS) and as the additive agent it was used the semi-synthetic surfactant castor oil (5%), aiming at a production of a B7-OS fuel with lower wear action on surfaces of metal alloys. Tribological tests showed that the diesel and B7-OS biodiesel was more susceptible to oxidative processes than the B7-AD sample and also, showed greater stability, viscosity, friction reduction and lower wear materials. Therefore, B7-AD is herein indicated as an efficient fuel with lower environmental impacts.