PRODUCT DEVELOPMENT CHEMICALS BIODEGRADABLE WITH STEEL PROTECTIVE ACTION TO CORROSION AISI 1018 AND STEEL WEAR AISI 52100 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 (ME) as corrosion inhibitors on carbon steel AISI 1018 in saline medium. The tested samples (SDBS-AS, SDBS-ME and SDBS-OCS-ME) 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 systems 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 (kerosene) and 60% of water], and also SDBS mixed with OCS (saponified coconut oil, a semisynthetic surfactant) on microemulsion system so called SDBS-OCS-ME), containing 40% C/S {[1% of SDBS and 99% of OCS, such as C/S=1] 20% de OCS/DBS (99:1) e 20% de butan-1-o, 5% of kerozene and 55% of water}. Comparatively, the AISI 52100 metal deterioration, caused by fuels, was studied for diesel, a B7-OC mixture with 93% of diesel S10 and 7% of coconut oil biodiesel, a B7-OS mixture with 93% of diesel S10 and 7% of soybean oil biodiesel, as well as soybean oil additive biodiesel (B7-OS-AD). Semisynthetic surfactant prepared from vegetal oils, were used as additive agents aiming at biodiesel fuel production with lower damage on surfaces of metal alloys. Tribological tests showed that the fuels diesel, B7-OC and B7-OS were more susceptible to oxidative processes than the B7-OS-AD (with 5% of saponified castor oil, as the additive surfactant), which showed greater stability, viscosity and lower wear action on metal (32.9% of reduction). Therefore, B7-OS-AD is herein indicated as an efficient fuel with lower environmental impacts.