Evaluation of Aqueous Coffee Husks Extracts as a Corrosion Inhibitor of 1020 Carbon Steel in 1 mol L-1 HCl Solution

Abstract

Corrosive processes in acidic medium reduce the performance and durability of metallic materials, causing problems to several industries. Corrosion inhibitors are commonly used to decrease these effects. As these inhibitors must be ecologically friendly currently, this work evaluated the anticorrosive effect of natural extracts of coffee husks (Coffea arabica L.) in the protection of carbon steel in 1 mol L-1 HCl solution. Extractions were performed using water as the extraction solvent. The polyphenols content increased with the extraction temperature, and the extracts were produced using 100 ºC. Extract concentrations of 10, 20 and 30 % v/v were analyzed as inhibitors for carbon steel in acid medium, using weight loss and electrochemical tests, as well as scanning electron microscopy. There was an increase in the inhibition efficiency as the extract concentration increased, reaching values around 97 % using 30 %v/v of extract for the weight loss tests.

Optimization of Espresso Spent Ground Coffee Waste Extract Preparation and the Influence of its Chemical Composition as an Eco-friendly Corrosion Inhibitor for Carbon Steel in Acid Medium

“…As the extraction conditions were optimized in the present work, the inhibitory performances of these SCG extracts were superior to other eco-friendly inhibitors based on coffee-residues extracts, such as roasted coffee and coffee husks aqueous extracts produced by infusion 16,23 . Also, their anticorrosive efficiency was similar to those using ground coffee aqueous extract prepared by infusion 17 and coffee husks aqueous extracts obtained by decoction 21 , always using HCl 1.0 mol L -1 as the aggressive medium. Nonetheless, it is necessary to point out that these comparisons must be carried out carefully, because they do not consider several parameters, such as the different extraction techniques, the initial waste mass, and the amount of extract added to the aggressive solution, for example.…”

“…Tafel parameters were obtained from the polarization curves using GPES 4.9 software. IE % values were also calculated using the corrosion current densities (j corr ) obtained from the potentiodynamic polarization curves by the Tafel extrapolation method (Equation 2) 21 . j corr,0 and j corr are the corrosion current density values obtained for the system in the absence and the presence of the inhibitor extract, respectively.…”

“…The data obtained in the EIS assays were simulated using the equivalent electric circuit model 21,38 presented in Figure 4, and the simulation results are presented in Table 3, while the simulated curves are also shown (full line) in Figures 2 and 3. In this circuit, R s represents the solution resistance, R ct is the charge transfer resistance, and CPE is the constant phase element (represented by Q and N) associated with the electrical double layer capacitance.…”

“…Other factors such as pH, temperature, sample mass, and extraction time may be studied, as well as sequential steps in order to maximize the extraction. 12,20 In most of the studies concerning the production of eco-friendly corrosion inhibitors extracts, however, the extraction parameters are chosen randomly or based in univariate experiments 17,[21][22][23] . These procedures are time-consuming, and a large number of experiments are generally needed to perform the extraction.…”

Evaluation of Efficiency of Avocado Seed Powder (Persea Americana) as a Corrosion Inhibitor in Sae 1008 Carbon Steel in Acidic Medium / Avaliação Da Eficiência Da Semente De Abacate Em Pó (Persea Americana) Como Inibidor De Corrosão Em Aço Carbono Sae 1008 Em Meio Ácido

“…This model is frequently used to fit EIS plots of carbon steel in acidic medium, with or without inhibitor. 18,19,25,[34][35][36]…”