Volume 20 Preprint 10


Hydrogen permeation studies on the corrosion of stainless steel in acid medium using an eco-friendly inhibitor

S. Karthikeyan, P.A.Jeeva, G.Sundaramali

Keywords: Corrosion, potential, hydrogen permeation, impedance, inhibition

Abstract:
The analysis of hydrogen gas ingress during the corrosion of stainless steel in pickling acid such as 2N H2SO4 in the presence and absence of an ecofriendly inhibitor Thiamphenicol[TPC] has been carriedout using mass loss, gasometric and electrochemical studies. The antibiotic seems to be more effective in plummeting the dissolution of steel in 2N H2SO4 .Potentiodynamic polarization clearly indicated that the inhibitor follows mixed mode of inhibition in 2N H2SO4 medium. Hydrogen permeation and EIS measurements have confirmed that the present antibiotic checks the dissolution of SS 304 efficiently in sulphuric acid . The theoretical values of EHOMO, ELUMO, ΔE and dipole moment in the presence of inhibitor established its effective adsorption on SS 304 metal surface.

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1 Hydrogen permeation studies on the corrosion of Hydrogen permeation studies on the corrosion of Hydrogen permeation studies on the corrosion of Hydrogen permeation studies on the corrosion of stainstainstainstainless steel in less steel in less steel in less steel in acid mediumacid mediumacid mediumacid medium using an using an using an using an ecoecoecoeco----friendlyfriendlyfriendlyfriendly inhibitorinhibitorinhibitorinhibitor S SSS.... KarthikeyanKarthikeyanKarthikeyanKarthikeyan1111****, P.A.Jeeva, P.A.Jeeva, P.A.Jeeva, P.A.Jeeva1111, G.Sundaramali, G.Sundaramali, G.Sundaramali, G.Sundaramali2222 1 Centre for Innovative Manufacturing Research, VIT University, Vellore -632014 , India School of Mechanical Engineering, VIT University, Vellore -632014 , India *Corresponding author: skarthikeyanphd@yahoo.co.in Abstract AbstractAbstractAbstract The analysis of hydrogen gas ingress during the corrosion of stainless steel in pickling acid such as 2N H 2SO4 in the presence and absence of an ecofriendly inhibitor Thiamphenicol[TPC] has been carriedout using mass loss, gasometric and electrochemical studies. The antibiotic seems to be more effective in plummeting the dissolution of steel in 2N H 2SO4 .Potentiodynamic polarization clearly indicated that the inhibitor follows mixed mode of inhibition in 2N H2SO4 medium. Hydrogen permeation and EIS measurements have confirmed that the present antibiotic checks the dissolution of SS 304 efficiently in sulphuric acid . The theoretical values of EHOMO, E LUMO, ∆E and dipole moment in the presence of inhibitor established its effective adsorption on SS 304 metal surface. K KKKeywords :eywords :eywords :eywords : Corrosion, potential, hydrogen permeation, impedance, inhibition 1.Introduction 1.Introduction1.Introduction1.Introduction In recent years , the medicines such as antibiotics and drugs are preferentially used as corrosion inhibitors due to their ecofriendliness [1-4]. Hetero cyclic compounds with sulphur, nitrogen and oxygen atoms in their exo cyclic rings have widely been reported as inhibitors for metals in acidic media [5-8]. The careful analysis of literature studies clearly reveal that no systematic approach is existing on the inhibitive action of Thiamphenicol [TPC] in high aggressive acid solutions.. The corrosion inhibiting property of this antibiotics is attributed to its molecular structure. The unshared pair of electrons on nitrogen of ethyl acetamido groups of TPC molecules and delocalization of electrons of methyl sulphonyl moiety of the present 2 drug ease the adsorption of the compound on surface of stainless steel . All the above investigations depict a general information that no significant data is seen on the performance of this eco friendly molecules as effective corrosion inhibitor and in bringing down the ingress of hydrogen gas through steel during pickling . It falls under the class of methyl sulphonyl acetamido antibiotic and used to heal a variety of bacterial infections. 2.Experimental 2.Experimental2.Experimental2.Experimental Stainless steel 304 specimens of the following composition was widely used. C= 0.08% , Si = O%, Ni = 8%, Cr = 18% and Fe= balance with exposed area of 4 x 1 x 0.020 cm were employed for mass loss and hydrogen permeation measurements. A stainless steel cylindrical rod of the same composition as above and embedded in araldite resin with an exposed area of 0.3 cm 2 was used for potential-current plots and EIS measurements. The compound was mainly monitored by a Mass loss studies as investigated by Madhavan et al [9]. Both cathodic and anodic potential- current curves were recorded potentiodynamically (1 mV s -1) using corrosion measurement system BAS Model: 1OOA computerised electrochemical analyser (made in West Lafayette, Indiana) and PL-10 digital plotter (DMP-40 series, Houston Instruments Division). A platinum foil of 4 cm2, Hg/Hg 2Cl2/KCl (satd) was used as auxiliary and reference electrodes, respectively. The hydrogen permeation study was performed using standard procedure of Devanathan and Stachurski's two compartment cell, as described earlier.[9] Double layer capacitance (Cdl) and charge transfer resistance values (R,) were obtained using EIS measurements . 3. RESULTS AND DISCUSSION 3. RESULTS AND DISCUSSION3. RESULTS AND DISCUSSION3. RESULTS AND DISCUSSION 3.1 3.1 3.1 3.1 MassMassMassMass loss and Gasometric measurementsloss and Gasometric measurementsloss and Gasometric measurementsloss and Gasometric measurements Table 1 showed the values of inhibition efficiency for various concentrations of Eco friendly inhibitor for the corrosion of SS 304 in 2N H2SO4 obtained from weight loss and gasometric measurements. It was noticed that the inhibitor brings down the 3 corrosion of stainless steel effectively in H2SO4 . This can be accredited to the lesser adsorption of sulphate ions on the steel surface, thereby allowing more space for this eco-friendly inhibitor to get adsorbed on SS 304 in 2N H2SO4 .Hence in sulphuric acid medium ,the coverage of the SS 304 by the TPC molecules is noticeably greater , giving rise to higher values of inhibition performance for all concentrations of the antibiotic used. The electronic structure of the compound is given in Figure 1. Figure 1. Structure of Thiamphenicol The retardation on the dissolution of SS 304 in acid medium favored by TPC molecules were involving the following interactions: 1.The interaction between the lone pairs of electrons of the nitrogen atoms of the ethyl acetamido groups of inhibitor and the positively charged metal surface [10]. 2.The interactions between delocalized electrons of the methyl sulphonyl groups and the positively charged metal surface of the green inhibitor [11]. It is found that there is a very good agreement between the values of inhibition efficiency obtained by mass loss and gasometric studies. 3.2 3.2 3.2 3.2 PotentiPotentiPotentiPotentiodynamic polarization measurementsodynamic polarization measurementsodynamic polarization measurementsodynamic polarization measurements Table 2(a) and 2(b) gave the results of potential-current plots such as Tafel slopes ( b a and bc ),corrosion current (I corr ) and corrosion potential (E corr ) and inhibition efficiency obtained from potentiodynamic polarization studies for SS 304 in 2N H2SO4 containing various concentrations of antibiotic molecule. It can be envisaged from table that results of Tafel slopes and I corr are very much similar to those reported 4 earlier [12,13.] Further it is well-known that increasing concentrations of TPC inhibitor increases the values of both b a and bc in unequal fashion justifying that the inhibition of corrosion of SS 304 in 2N H 2SO4 follows mixed mode of interaction. Values of E corr was progressed to positive direction in the presence of different concentrations of TPC molecules. This can be ascribed to the formation of firmly adsorbed inhibitor film on the SS 304 metal surface. The presence of increasing quantity of inhibitor molecule significantly retards Icorr values in 2N H2SO4 . It can also be observed that most of the values of inhibition efficiency obtained by mass loss and potentiodynamic polarization studies agree very well. 3.3 Hydrogen3.3 Hydrogen3.3 Hydrogen3.3 Hydrogen permeation permeation permeation permeation studistudistudistudieseseses The results of ingress of hydrogen gas studies for the dissolution of stainless steel 304 in the presence and absence of the TPC inhibitor are given in Table 3. It can be concluded from the table that the existence of inhibitor in 2N H2SO4 bring down the permeation current and does not encourage the ingress of hydrogen gas into SS 304 . The declining trend in permeation currents can be attributed to the active formation of protective layer on the surface of metal surface [14,15] . It can be realized from the table that the decrement of permeation current is more, if the concentration of Thiamphenicol inhibitor is high. 3.4 Impedance 3.4 Impedance 3.4 Impedance 3.4 Impedance analysisanalysisanalysisanalysis Values of charge transfer resistance (Rt )and double layer capacitance (Cdl) obtained from EIS measurements are presented in table 4.It can be found in table that the values of R t is seen to escalation with enrichment of green compound dosages in 2N H 2SO4 . Values of double layer capacitance are confirming that steel dissolution is more in 2N H 2SO4 in the absence of Thiamphenicol. It was observed that values of C dl are lowered by increasing concentrations of inhibitor in sulphuric acid medium. This can be attributed to the effective adsorption of the antibiotic molecule on the surface of SS 304 with increase in its quantity to the electrolyte. A plot of surface coverage (ø ) versus log C gave a straight line signifying that the adsorption of green inhibitor on SS 304 surface from 2N H2SO4 follows Temkin's 5 adsorption isotherm [16]. This is main sustenance to corrosion inhibition by this molecule , as a result of its adsorption on the surface of SS 304. 4. Conclusions4. Conclusions4. Conclusions4. Conclusions 1. TPC, an eco friendly inhibitor retards the the corrosion of SS 304 in 2N H2SO4 effectively. 2. The inhibition of corrosion of stainless steel by the compound in pickling medium falls under mixed control. 3. The presence of Thiamphenicol molecule in 2N H2SO4 found to reduce the ingress of hydrogen gas through SS 304 surface. 4. R t and Cdl values studied from impedance measurements prove the impressive performance of the inhibitor. 5. The adsorption of the compound on SS 304 surface obeyed Temkin's adsorption isotherm. References: References:References:References: [1]. Rhodanine azosulpha drugs as corrosion inhibitors for corrosion of 304 stainless steel in hydrochloric acid solution, M. Abdallah, Corros. Sci,44, pp728, 2002 [2]. Antifungal drugs as corrosion inhibitors for aluminium in 0.1 M HCl, I.B. Obot, N.O. Obi-Egbedi, S.A. Umoren, Int. J. Electrochem. Sci, Vol. 4,2009 [3]. Torsemide and Furosemide as Green Inhibitors for the Corrosion of Mild Steel in Hydrochloric Acid Medium, S. Harikumar and S. Karthikeyan, Industrial and Engineering Chemistry Research, 52(22), pp. 7457-7469, 2013 [4]. Adsorption characteristics and corrosion inhibitive properties of Eco friendly inhibitorfor Aluminium corrosion in hydrochloric acid, I. Obot,N.Umoren, Int. J. Electrochem. Sci, Vol. 4, pp. 863-877, 2009 [5]. Inhibition of mild steel corrosion in hydrochloric acid solution by cloxacillin drug, S. Harikumar and S. Karthikeyan, Journal of Materials and Environmental Studies, Vol.5, pp. 925-934, 2012 [6]. Influence of some thiazole derivatives on corrosion of mild steel in hydrochloric acid, M.A. Quraishi, M.A.W. Khan, M. Ajmal, Anti-Corros. Methods Mater, 43, 5, 1996 6 [7]. The inhibitive action of cyclohexyl thiourea on corrosion and hydrogen permeation through mild steel in acidic solutions, S.Karthikeyan, S.Harikumar, G. Venkatachalam, S.Narayanan, R.Venckatesh, International Journal of ChemTech Research, 4(3), pp. 1065-1071, 2012. [8]. Electrochemical studies of two corrosion inhibitors for iron in HCl, Al-Andis, N.Khamis, E. Al-Mayouf, H. Aboul b Enicm, Corros. Prev. Cont rol, 42, 13,1995 [9]. L-Methionine methyl ester hydrochloride as corrosion inhibitor of iron in 1 M HCl, B. Hammouti, M. Aouniti, M. Taleb, M. Bri ghli, S. Kertit, Corrosion, 51,441, 1995 [10]. Influence of anions on corrosion inhibition and hydrogen permeation through mild steel in acidic solutions in the presence of p-tolyl thiourea, K. Madhavan, S. Karthikeyan, S.V.K. Iyer, Ind. J.Chem. Tech, 9, pp68,2002 [11]. The Structure of the Electrical Double Layer at the Metal Solution Interface, M.A. Devanathan, B. Til ak, Chem.Revs, 65, pp. 635, 1965 [12]. Surface coordination chemistry of monometallic and bimetallic eletrocatalysts, Soriaga, Chem.Revs, 90, pp77, 1990 [13]. The inhibition of sulphuric acid corrosion of 410 stainless steel by thioureas, Reeta Agarwal, T.K.G. Namboodri, Corros.Sci, 30, pp37, 1990 [14]. Mechanism of corrosion and its inhibition, K. Madhavan, PhD Thesis, Alagappa Uni versity, India, June 1996 [15]. W.Waiter Voss, J.Chemistry of Amides, Zabersky Edition, Interscience, Newyork, 187, 1997 [16]. A.K. Lahiri, N.G. Banerjee, NML. Tech. Journal, 5, pp33, 1963 [17]. Gu Hough, Zhou Zhongbai, Tao Yingachu , Yao Luaw, Wahan Dauxe Xuebao, Ziran Kexuebaw, 2, pp57, 1982 [18]. G. Trabanelli and Zucchui F.Revon, Corrosion and coatings, 1, pp47, 1973 [19]. The use of Quantum chemical methods in corrosion inhibitor studies, G. Gece, Corrosion Science, pp.2981-2992, 2008 [20]. Inhibition Effect of Amoxicillin drug on the Corrosion of Mild Steel in 1N Hydrochloric acid Solution, S. Hari Kumar, S. Karthikeyan, S.Narayanan and K.N.Srinivasan, International Journal of ChemTech Research, 4(3), pp. 1077-1084, 2012. 7 [21]. Corrosion inhibition of mild steel in 1M H2SO4 by Ampicillin as an inhibitor, S. Hari Kumar, S. Karthikeyan, P.A. Jeeva, Journal of Corrosion Science and Engineering, Vol16, 2013 [22]. The retardation of dissolution of Al-Sic composites in acidic medium - A green approach, V. Umasankar, S. Karthikeyan, M. Anthony Xavier, Journal of Corrosion Science and Engineering, 16, pp47, 2013 [23].Ethane-2- thioamido-4-amino-N-(5-methylisoxazol-3-yl)-benzene sulfonamide: A novel inhibitor for the corrosion of mild steel in 1N HCl , S. Karthikeyan, N. Arivazhagan, S. Narayanan, Journal of Corrosion Science &Engineering, Vol.16, 2013 [24]. Performance characteristics of 1, 3-diorthotolyl thiourea on the corrosion of mild steel in 5% NaCl, S. Karthikeyan, N. Arivazhagan, D. Ramkumar, S. Narayanan, Journal of Corrosion Science &Engineering, Vol.16, 2013. Table 1. Values of inhibition efficiency for the corrosion of mild steel Table 1. Values of inhibition efficiency for the corrosion of mild steel Table 1. Values of inhibition efficiency for the corrosion of mild steel Table 1. Values of inhibition efficiency for the corrosion of mild steel in in in in 2N 2N 2N 2N HHHH2222SOSOSOSO4444 in in in in the presence of di the presence of dithe presence of dithe presence of different concentrations of fferent concentrations of fferent concentrations of fferent concentrations of Eco friendly inhibitorEco friendly inhibitorEco friendly inhibitorEco friendly inhibitor obtained from weight obtained from weight obtained from weight obtained from weight loss and gasometric measurements. loss and gasometric measurements.loss and gasometric measurements.loss and gasometric measurements. Concentration Concentration Concentration Concentration of Inhibitor of Inhibitor of Inhibitor of Inhibitor (mM) (mM)(mM)(mM) Inhibition efficiency Inhibition efficiencyInhibition efficiencyInhibition efficiency Weight loss Weight loss Weight loss Weight loss Studies StudiesStudiesStudies Gasometric Gasometric Gasometric Gasometric measurements measurementsmeasurementsmeasurements 10 20 30 40 67 89 97 85 66.7 89 96.7 84.8 8 Table 2. Corrosion kinetic parameters of Table 2. Corrosion kinetic parameters of Table 2. Corrosion kinetic parameters of Table 2. Corrosion kinetic parameters of SS 304 SS 304 SS 304 SS 304 in in in in 2N2N2N2N HHHH2222SOSOSOSO4444 in the presence of in the presence of in the presence of in the presence of different concentrations of different concentrations of different concentrations of different concentrations of Eco friendly inhibitorEco friendly inhibitorEco friendly inhibitorEco friendly inhibitor obtained from obtained from obtained from obtained from potentiodynamic potentiodynamic potentiodynamic potentiodynamic polarization polarization polarization polarization studies.studies.studies.studies. Concentration Concentration Concentration Concentration of Inhibitor of Inhibitor of Inhibitor of Inhibitor (mM) (mM)(mM)(mM) E corr (mV) Tafel slopes in mV in dec -1 I corr mA cm -1 Inhibition efficiency (%) ba bc No Inhibitor -376 75 131 180 --- 10 -372 73 138 48.7 81.8 20 -361 61 140 35.6 86.7 30 -358 50 139 6.96 97.4 9 Table 3 Table 3Table 3Table 3.... Values of permeation current for the corrosion of mild steel in Values of permeation current for the corrosion of mild steel in Values of permeation current for the corrosion of mild steel in Values of permeation current for the corrosion of mild steel in 2N 2N 2N 2N HHHH2222SOSOSOSO4444 in in in in the presence of different concentrations o the presence of different concentrations othe presence of different concentrations othe presence of different concentrations of f f f inhibitor.inhibitor.inhibitor.inhibitor. Concentration of Concentration of Concentration of Concentration of Inhibitor (mM) Inhibitor (mM)Inhibitor (mM)Inhibitor (mM) Permeation current Permeation current Permeation current Permeation current (•.A) (•.A)(•.A)(•.A) Pickling acid Pickling acid Pickling acid Pickling acid No inhibitor 10 20 3 0 19.9 12.3 10.2 6.5 Table 4.Im Table 4.ImTable 4.ImTable 4.Impedance parameters for the corrosion of pedance parameters for the corrosion of pedance parameters for the corrosion of pedance parameters for the corrosion of StainlessStainlessStainlessStainless steel steel steel steel 304 304 304 304 inininin 2N 2N 2N 2N HHHH2222SOSOSOSO4444 in in in in the presence of different concentrations of the presence of different concentrations of the presence of different concentrations of the presence of different concentrations of green compoundgreen compoundgreen compoundgreen compound Concentration Concentration Concentration Concentration of Inhibitor of Inhibitor of Inhibitor of Inhibitor (mM) (mM)(mM)(mM) H HHH2222SOSOSOSO4444 Charge Transfer Double layer capacitance 10 resistance (R t) Ohm.cm 2 (C dl) •F.cm-2 No inhibitor 10 20 30 6.97 54 62 130 185 35.15 24.79 4.63