An important world crop – barley – as a new green inhibitor for acid corrosion of steel

Abstract

Purpose -The purpose of this paper was to test the extract of barley as an environmentally friendly inhibitor for the acid corrosion of steel due to its wide availability as a popular major crop and its richness with different chemical constituents reported in literature (40) like alanine, glycine, serine, aspartic acid, leucine, valine, tyrosine and isoleucine with various number of functional groups that are able to chelate metal cations and to discuss the effect of temperature on its inhibition efficiency. Design/methodology/approach -Electrochemical impedance spectroscopy (EIS) and polarization measurements were carried out using frequency response analyzer Gill AC instrument. The frequency range for EIS measurements was 0.1 Յ f Յ 1 ϫ 103 with an applied potential signal amplitude of 10 mV around the rest potential. Polarization measurements were carried out at a scan rate of 30 mV/min, utilizing a three-electrode cell. A platinum sheet and saturated calomel electrode were used as counter and reference electrodes, respectively. The working electrode was constructed with steel specimens that have the following composition (weight per cent): C, 0.21; S, 0.04; Mn, 2.5; P, 0.04; Si, 0.35; and balance Fe. Findings -Barley extract could act as an effective corrosion inhibitor for the acid corrosion of steel. The inhibiting action of the barley extract was attributed to its adsorption over the metal surface that blocks the available cathodic and anodic sites. Adsorption isotherms indicated that the adsorbed extract molecules cover one active center over the metal surface. Originality/value -The research included the first use of an important world crop as an effective corrosion inhibitor that can reduce the corrosion of steel to an extent of 94 per cent.

Barley Agro-industrial Residues as Corrosion Inhibitor for Mild Steel in 1mol L-1HCl Solution

“…The various hazardous effects of most synthetic corrosion inhibitors have motivated the use of safe natural products. They can provide a renewable source of naturally available chemical compounds that can be extracted by simple extraction and at low cost 2 .…”

“…Recently, interest has increased with the development and use of low-cost and eco-friendly compounds as corrosion inhibitors [1][2] . In our previous works, the effect of aqueous extracts of spent coffee grounds, coffee husk, garlic, and onion peels, fruit peels (mango, orange, passion fruit and cashew), grape pomace and papaya seeds on the corrosion of carbon steel in 1 mol L −1 HCl was studied [9][10][11][12][13][14][15] .…”

“…Barley is an excellent source of β-glucans, phenolic compounds, acid ascorbic, glutathione, and several amino acids as alanine, glycine, serine, leucine, valine, tyrosine, and isoleucine, which could be able to adsorb onto the metallic surface 2 .…”

Green Corrosion Inhibitors for Coatings

“…To make environment clean, scientists are constantly exploring natural new products as green corrosion inhibitors. Research work done on this topic includes utilization of barley remains [59], opuntia [60], vernonia [61], hibiscus [62], mangrove [63], tree roots [64], and overabundance of others are explained in Table 3.…”

Inhibitive action of tara tannin in rust converter formulation

“…Weight loss measurements and electrochemical techniques (measurements of the corrosion potential and the polarization resistance, potentiodynamic polarization and electrochemical impedance spectroscopy) have been used to evaluate the inhibition efficiency of natural extracts. Earlier studies include the use of rice bran (Dong et al , 2011), Opuntia stem (El-Etre, 2003), Lawsonia leaves (El-Etre et al , 2005), Artemisia pallens (Garai et al , 2012), Thyme leaves (Ibrahim et al , 2012), Musa paradisica peels (Ji et al , 2015), Rhazya Stricta Decne leaves (Nahlé et al , 2014), watermelon rind (Odewunmi et al , 2015), Phyllanthus amarus leaves and seeds (Okafor et al , 2008), Archachatina marginata snail shells (Okoronkwo et al , 2015), henna leaves (Ostovari et al , 2009), barley (Saadawy, 2015), caffeic acid (De Souza and Spinelli, 2009), Opuntia ficus-indica peels (Suarez-Hernandez et al ., 2014), Vigna unguiculata husks (Umoren et al , 2008), nettle extracts (Zaabar et al , 2014) as green corrosion inhibitors for mild steel and aluminum in acidic media. The inhibitive action of plant extract on the corrosion of carbon steel in chloride media has also been studied (Abdel-Gaber et al , 2011; El-Etre and Abdallah, 2000; Qian et al , 2013; Rahim et al , 2008).…”