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

Abstract

This work proposes the reuse of spent ground coffee waste (SCG) extracts as eco-friendly corrosion inhibitors for carbon steel in acid medium, and the correlation between their anticorrosive efficiency and chemical composition. The extraction method was optimized using a central composite design, and the chemical composition of the extracts was accessed using UV-Vis spectrometry, HPLC, and ICP-OES. EIS and Potentiodynamic Polarization (PP) tests evaluated the anticorrosive properties of the extracts. Total phenol content ranged from 93 mg L-1 to 219 mg L-1 Gallic Acid Equivalent. The highest concentration of phenolic compounds was observed for syringic acid (78.67 mg L-1), while the lowest concentration was verified for (-)-epigallocatechin-3-O-gallate (0.01 mg L-1). The Pearson correlation coefficient showed no correlation between the R ct and the total phenol content, although, positive correlations with the R ct was observed for caffeic acid, (+)-catechin, ferulic acid, and protocatechuic acid. EIS analysis revealed that all of the extracts could act as corrosion inhibitors. The best performance was verified for C3 extract (IE % = 94.83%). PP tests showed that this extract acted as a mixed inhibitor, with a predominant cathodic effect. Therefore, the valorization of the extracts as corrosion inhibitors was successfully achieved.

Green Corrosion Inhibitors Based on Plant Extracts for Metals and Alloys in Corrosive Environment: A Technological and Scientific Prospection

“…The articles found in the SciELO database describe the use of various materials as green inhibitors, as listed in Table 3. Among the possible inhibitors evaluated there were: coffee powder [32], caffeine [33], Aniba canelilla [34], Hibisco-colibri [35], mango and orange peels [36], garlic [37] and castor bean [38]. All materials (Table 3) were analyzed to discover whether they inhibit carbon steel corrosion in acid medium and showed inhibition efficiencies above 80%.…”

Spent coffee grounds: A sustainable approach toward novel perspectives of valorization

“…Ronga et al (2020), studied the valorization of SCG, to produce lightweight clay ceramic aggregates suitable for nursery grapevine production (Ronga et al, 2020). Da Costa et al (2020), reported the recycling of SCG as an eco‐friendly corrosion inhibitor for carbon steel. The obtained extract was found to have the best anti‐corrosion performance (94.83%) (Da Costa et al, 2020).…”

“…Da Costa et al (2020), reported the recycling of SCG as an eco‐friendly corrosion inhibitor for carbon steel. The obtained extract was found to have the best anti‐corrosion performance (94.83%) (Da Costa et al, 2020).…”

Oil Extracted from Spent Coffee Grounds as a Green Corrosion Inhibitor for Copper in a 3 wt% NaCl Solution

“…Extensive research in the literature highlights the considerable potential of used coffee grounds in producing value-added energy and non-energy-related products due to their significant content of fatty acids, cellulose, esters, lignin, and hemicelluloses [15][16][17]. Diverse investigations have been conducted to examine the corrosion-inhibitory efficacy of SCG extract across a spectrum of metals and within various environmental conditions [18][19][20][21][22]. According to research by Bouhlel et al [18,23], the hydro-alcoholic extract of used coffee grounds effectively protects C38 steel against corrosion in 1 M hydro-alcoholic acid.…”