Effects of Sodium Thiosulfate and Sodium Sulfideon the Corrosion Behavior of Carbon Steel in an

MDEA-Based CO2 Capture ProcessW. Emori, S.L. Jiang, D.L. Duan, and Y.G. Zheng

(Submitted July 25, 2016; in revised form October 19, 2016)

The corrosion behavior of carbon steel has been tested in the presence of sodium thiosulfate and sodiumsulfide in an MDEA-based CO2 capture system using electrochemical methods, weight loss measurementsand surface analysis. The results of electrochemical measurements revealed that both thiosulfate and sulfideshowed corrosion resistance properties to carbon steel corrosion. The corrosion resistance for the systemwith thiosulfate increased with concentration, while the system with sulfide yielded better corrosionresistance to carbon steel at lower concentrations as increase in sulfide concentration decreased the cor-rosion resistance. The corrosion inhibition behaviors for both systems at 0.05 M salt concentrations wereconfirmed by weight loss measurement, and the solution with sodium sulfide exhibited a better inhibitionwith time.

Keywords carbon steel, CO2 capture, CO2 corrosion, corrosioninhibition, MDEA, sulfide, thiosulfate

1. Introduction

The chemical absorption method for carbon capture andstorage (CCS) to reduce anthropogenic CO2 emission inindustrial flue gas streams has become increasingly popularwith time. The method typically involves the reaction of anabsorbent with CO2 to form salts. After the capture process,CO2 is recovered by a reversal of the chemical reactionachieved by the application of heat, a reduction in pressure orboth (Ref 1, 2). Many researchers have focused on the choice,potency and reliability of a number of absorbents particularlyamine-based (Ref 3-11), as well as improvement of operations(Ref 12-18). Operating parameters such as amine concentration,dissolved CO2, process temperature and some amine degrada-tion products have been highlighted to induce corrosion in post-combustion units (Ref 19).

Although there are extensive research data available forpost-combustion acid gas capture using amine solution, it isworthwhile to investigate the corrosivity effects of contami-nants in the systems. The high level of oxygen, SOx and NOx inpost-combustion acid gas capture becomes one of the primaryroutes for contaminant source where they either lead to theformation of heat-stable salts (Ref 20) or react with the amine toproduce degradation products (Ref 6). Another source may beby direct contaminant introduction through make-up water (Ref21).

It is generally reported that both amine degradation productsand heat-stable salts influence the corrosivity of amine solutionsand that heat-stable salts reduce the acid gas removal capacityof the amine solutions because they react irreversibly with theamine (Ref 22). Duan et al. (Ref 20) reported that the presenceof heat-stable salts slightly increased the corrosion rates ofcarbon steel in CO2-loaded MDEA systems but did not changethe corrosion behavior of carbon steel. Heat-stable salts arecorrosive because they lower pH and increase the conductivityof the absorbent solution. However, Tanthapanichakoon andVeawab (Ref 23) investigated the influence of some heat-stable salts on the corrosion behavior of carbon steel in amonoethanolamine (MEA) system and concluded that whilesome heat-stable salts induced a uniform corrosion, othersincluding sodium thiosulfate retarded the rate of uniformcorrosion or functioned as corrosion inhibitors in the MEAsystem for CO2 capture. However, supporting reasons for theinhibitive behaviors were not reported. Srinivasan et al. (Ref24) further evaluated the inhibition performance of sodiumthiosulfate in MEA systems and found active inhibition forshort-term exposure test, while successes were not recorded forlong-term exposure tests. Additionally, a few researchers havesuggested that the presence of sulfide could either accelerate orinhibit carbon steel corrosion depending on the experimentalconditions. A significant inhibition with low H2S concentrationwas reported by Ma et al. (Ref 25) and Abelev et al. (Ref 26),and the inhibition effect is suggested to be related to theformation of iron sulfide film (Ref 27, 28). Nonetheless, whileprevious studies in this area are focused on MEA, not muchcould be found for MDEA systems. Furthermore, informationfor investigations of sodium sulfide in amine systems is limited.

These necessitated the reasons for espying a comprehensiveevaluation on the effects of sodium thiosulfate and sodiumsulfide on the corrosion behavior of carbon steel in MDEAsolutions loaded with CO2. In the present study, electrochem-ical behavior of carbon steel in CO2-loaded MDEA (50 wt.%)solution was studied at a temperature of 50 �C and ambientpressure, simulating the absorber conditions of the CO2 capture

W. Emori, S.L. Jiang, D.L. Duan, and Y.G. Zheng, CAS KeyLaboratory of Nuclear Materials and Safety Assessment, Institute ofMetal Research, CAS, Shenyang 110016, People�s Republic of China.Contact e-mail: sljiang@imr.ac.cn.

JMEPEG �ASM InternationalDOI: 10.1007/s11665-016-2458-9 1059-9495/$19.00

Journal of Materials Engineering and Performance

unit of a fossil-fueled power plant. The corrosion behaviorswere evaluated by electrochemical methods (potentiodynamicpolarization and electrochemical impedance spectroscopy [EIS]measurements) and weight loss measurements. Surface analyt-ical techniques (scanning electron microscopy [SEM] andenergy-dispersive x-ray spectroscopy [EDS]) were also appliedto obtain the surface morphology and chemical composition ofcorrosion products.

2. Experimental

2.1 Material and Solution

Carbon steel A36 was used in the present study with achemical composition as presented in Table 1. The specimenfor electrochemical measurements had an exposed area of1.0 cm2 and was polished with silicon carbide abrasive paperup to 800 grit, followed by being ultrasonically cleaned withethanol and water, and finally dried. The specimens for weightloss and surface analysis (SEM/EDS) had a total surface area of5.2 cm2 and were polished with silicon carbide abrasive paperup to 2000 grit.

An aqueous solution of 50 wt.% MDEA was prepared froma 99% MDEA reagent and deionized water. Before eachexperiment, a gas mixture (0.12 bar CO2 + 0.06 bar O2, withN2 as the balance gas) was purged into the test solution. TheCO2 loading at 50 �C was around 0.13 mol CO2/mol amine.The introduced contaminants were sodium thiosulfate(Na2S2O3) and sodium sulfide (Na2S). They were of industrialgrade with concentrations above 98%. The solution purgingwas for at least 4 h before the test in order to achieveequilibrium for the system. The system equilibrium wasconfirmed by steady pH values with time, and the solutionwas continuously purged during the experiment to maintain thegas concentrations.

2.2 Electrochemical Measurements

Corrosion test was carried out in a 0.5 L glass cell at 50 �Cunder atmospheric pressure (absorber condition). The test setupconsists of a glass cell, a three-electrode corrosion system(counter electrode: platinum wire, reference electrode: saturatedcalomel reference electrode (SCE), working electrode: carbonsteel A36, hot plate equipped with temperature controller, gas(nitrogen, oxygen and carbon dioxide) supply set, pH meter,and potentiostat (Gamry Reference 1000 potentiostat/galvanos-tat/ZRA). All potentials in this work were measured relative toSCE. Open circuit potential (OCP) measurements were takenfor 2 h. The potentiodynamic polarization tests were performedat a sweep rate of 0.1667 mV/s from �1.2 V (versus OCP) to�0.7 V (versus OCP). The EIS measurements were taken atOCP with a sinusoidal potential perturbation of 10 mV in afrequency range from 100 kHz to 10 mHz, and the obtainedEIS spectra were fitted using the Gamry software. Thepotentiodynamic polarization and EIS tests were performedwhen the OCPs became stable.

2.3 Weight Loss Measurement

Time-dependent corrosion rates were determined by weightloss method. The test consisted of solutions with and without0.05 M sodium thiosulfate and 0.05 M sodium sulfide. Thespecimens were pre-weighed, labeled and suspended in the testsolution. The specimens were retrieved after the set experi-mental duration (i.e., 7 days), carefully washed in a picklingacid solution and rinsed in distilled water, dipped in acetone,air-dried and re-weighed. The weight losses were determined asthe difference in weight of each carbon steel specimen beforeand after immersion in the test solutions. The corrosion rateswere calculated from the following equation (Ref 29):

Corrosion rate mm/yearð Þ ¼ 8:76� 104 � weightloss gð Þarea cm2ð Þ � density g=cm3ð Þ � time hð Þ

ðEq 1Þ

2.4 Surface Analysis

Specimens for surface analysis were immersed along withthose for weight loss measurements in the test solutions. Thespecimens were withdrawn from the test solutions, rinsed withdistilled water, dipped in acetone and air-dried. The surfacemorphology and phase compositions of corrosion productswere analyzed with SEM and EDS.

3. Results and Discussion

3.1 Potentiodynamic Polarization

Figure 1 presents the active region of the potentiodynamicpolarization curves of carbon steel in the test solutions with andwithout the test salts at different concentrations and the corrosionbehavior can be interpreted based on the polarization curves.Sodium thiosulfate addition (Fig. 1a) decreased the cathodiccurrent density of carbon steel slightly with a shift of the cathodiccurve toward less positive values from that of blank solutionwhile the anodic currents remained relatively unchanged. Thisobservation could be indicative of a corrosion resistancetendency of carbon steel in the presence of sodium thiosulfate.It is also observed that the cathodic current density successivelydecreased with increase sodium thiosulfate concentration.

Figure 1(b) reveals that the addition of sodium sulfidereduced the anodic current, whereas, the cathodic currents weresomewhat less affected. Additionally, the potential increased,indicating a reduction in the corrosion rate. These observationstend to give indications of the inhibition of the anodicdissolution reaction. It is, however, interesting to note that thepotential reversed above 0.05 M sodium sulfide concentrationas subsequent sodium sulfide additions reduced the potentialsteadily and increased the anodic current density. This obser-vation suggests that at concentrations above 0.05 M, theinhibition properties of sodium sulfide decreases. This isconsistent with investigations by Ma et al. (Ref 25) whichreported an increase in corrosion on electrode surfaces with

Table 1 Chemical composition (wt.%) of the working electrode

Material C Mn P S Cu Si Fe

Carbon steel 0.23 0.79 0.02 0.03 0.29 0.20 Bal.

Journal of Materials Engineering and Performance

solutions of higher H2S concentration compared with lowerconcentrations using SEM analysis. From the figure, it wasobserved that sulfide generally acted as a corrosion inhibitor butthe inhibitive property depreciated with increasing sulfideconcentrations.

3.2 Electrochemical Impedance Spectroscopy (EIS)Measurement

The Nyquist plots for carbon steel in the test solutionswithout and with sodium thiosulfate and sodium sulfide atdifferent concentrations are shown in Fig. 2(a) and 3(a).Figure 2(a) reveals that the diameter of the semicircle loopincreased with the addition of sodium thiosulfate leading to anincrease in the impedance indicating a corresponding increasein corrosion resistance of carbon steel. This suggests thatthiosulfate induced inhibition against CO2 corrosion of carbonsteel and the inhibitive effect is shown to increase withconcentration. For Fig. 3(a), the largest diameter and maxi-mum magnitude are observed for 0.05 M sodium sulfide. Thislends weight to the notion of inhibitive behavior for lowersodium sulfide concentrations. Subsequent increase in con-centration resulted to a decrease in the semicircle loop and themagnitude of impedance indicating a continuous decrease incorrosion resistance with increasing concentration. Thissupports the observation of a reduction in the inhibitiveproperty of sodium sulfide on carbon steel corrosion withincreasing concentration as reported for the potentiodynamicpolarization measurements.

Furthermore, impedance diagrams in the Bode format forthe same experimental data are shown in Fig. 2(b) and 3(b),respectively, for solutions with sodium thiosulfate and sodiumsulfide. The plot for the solution with sodium thiosulfaterevealed a continuous increase in the phase angle withconcentration indicating a continuous increase in corrosionresistance, while for the solution with sodium sulfide, amaximum phase angle was recorded for 0.05 M sodiumsulfide. The phase angle decreased with subsequent concentra-tions reaching a minimum at the 0.2 M sodium sulfide.

Figure 4 presents the electrical equivalent circuit used forthe analysis of the impedance plots. From the figure, Rs

represents the resistance of the solution, Rct and Cdl are thecharge transfer resistance and capacitance of the double layer,respectively, while Rf and Cf correspond to the resistance andcapacitance of the film, respectively. A constant phase element(CPE) was used instead of an ideal capacitance in order toaccount for the non-ideal frequency response of the displayeddata, thus, improving the fitting quality (Ref 30, 31). However,Cdl and Cf were used for simplicity.

The electrochemical parameters obtained by fitting theimpedance behaviors are given in Table 2. In the table,polarization resistance (Rp) was deduced from the expression(Ref 32):

Rp ¼ Rct þ Rf ðEq 2Þ

The calculated Rp can be used to evaluate the corrosionresistance of carbon steel in the tested systems as presentedin Fig. 5. The general trend of Rp for the solution withsodium thiosulfate shows that the value increased progres-sively with the thiosulfate concentration. This indicates acontinuous reduction in the corrosion rate of carbon steel bythe addition of sodium thiosulfate. On the other hand, the Rp

for the solution with sodium sulfide supports the observationsfrom the spectra of Nyquist and Bode plots where carbonsteel exhibited the highest resistance at 0.05 M sodiumsulfide and the resistance decreased with increasing saltconcentrations. Despite showing inhibitive behaviors tocarbon steel corrosion for all tested concentrations, thedecrease in carbon steel corrosion resistance with increasingsodium sulfide concentrations suggests a reversal of behaviorfrom corrosion inhibiting to corrosion promoting withadditional concentrations even above the reported testconcentrations.

The dependence of the degree of protectiveness of carbonsteel on the concentrations of sodium thiosulfate and sodiumsulfide was evaluated from EIS data by the expression:

Fig. 1 Potentiodynamic polarization curves of carbon steel in MDEA solution containing (a) sodium thiosulfate and (b) sodium sulfide

Journal of Materials Engineering and Performance

g ¼ Rn � Rc

Rn� 100 ðEq 3Þ

where g is inhibition efficiency, Rn and Rc are polarizationresistance values of carbon steel in the test solutions with and

without the presence of the salt. As shown in Fig. 6, the inhi-bition efficiency for the solution with sodium thiosulfate in-creased steadily with concentration with the 0.2 Mconcentration yielding 84.4%. On the other hand, the solutionwith 0.05 M sodium sulfide yielded the highest value of74.9% but this efficiency decreased with increase in sodiumsulfide concentration until reaching 14.7% for 0.2 M sodiumsulfide.

3.3 Time-Dependent Corrosion Experiments

Time-dependent corrosion tests for carbon steel were carriedout for the systems with and without 0.05 M sodium thiosulfateand 0.05 M sodium sulfide. Figure 7 presents the calculatedcorrosion rates for the systems, and it reveals that both saltsshowed good inhibition abilities for carbon steel corrosioncompared to the solution without salt. After 7 days, the solutionwith sodium thiosulfate reduced the corrosion rate of carbonsteel from 0.092 mm/year, recorded for the solution without

Fig. 2 (a) Nyquist and (b) Bode plots of carbon steel in MDEA solution containing sodium thiosulfate

Fig. 3 (a) Nyquist and (b) Bode plots of carbon steel in MDEA solution containing sodium sulfide

Fig. 4 Electrical equivalent circuit used to fit the EIS spectra

Journal of Materials Engineering and Performance

salt, to 0.008 mm/year while the solution with sodium sulfideyielded a corrosion rate of 0.003 mm/year. Since the corrosionrate evaluation by weight loss measurements at 0.05 Mconcentration for both the thiosulfate and sulfide agrees withresults from electrochemical measurements at the same con-centration, it is therefore worthwhile to calculate the inhibitionefficiency (g) of the salts to carbon steel corrosion. Sodiumthiosulfate achieved an inhibition efficiency of 91.3% whilesodium sulfide yielded 96.7%. The inhibition efficiency wascalculated from the expression:

g ¼ Rb � Rs

Rb� 100 ðEq 4Þ

where Rb and Rs are corrosion rates of carbon steel in the testsolutions without and with the presence of the tested salts,respectively.

3.4 SEM and EDS Characterization

The SEM micrographs of the CO2 corrosion product filmsformed on the surface of carbon steel at 50 �C after 7 days inMDEA systems with and without 0.05 M sodium thiosulfateand sodium sulfide are shown in Fig. 8. For the solution

Table 2 Electrochemical parameters obtained from the fitting of EIS data

Salt Concentration/M Rs/X cm2 Rct/kX cm2 Cdl/lF cm22 n Rf/kX cm2 Cf/lF cm22 n v2

Blank 87.3 2.21 6.6 0.92 59.4 312.1 0.43 2E�04Na2S2O3 0.05 54.9 2.89 7.2 0.88 77.6 288.8 0.45 2E�04

0.10 44.0 2.90 8.5 0.68 94.6 53.4 1.00 4E�030.15 38.7 2.91 9.8 0.91 166.7 60.9 0.41 6E�040.20 37.1 0.04 2.6 0.30 394.4 78.2 0.93 6E�04

Na2S 0.05 51.7 9.53 56.6 0.91 236.2 246 0.87 9E�040.10 44.2 7.19 40.2 0.85 127.3 69.8 1.00 1E�030.15 52.7 7.35 64.0 0.90 170.5 36.6 1.00 1E�030.20 30.2 2.92 58.8 0.83 69.3 146 0.74 7E�04

Fig. 5 Dependence of polarization resistance (Rp) of carbon steel on concentration of (a) sodium thiosulfate and (b) sodium sulfide in MDEAsolution

Fig. 6 Inhibition efficiency of sodium thiosulfate and sodium sul-fide from Rp evaluation of carbon steel corrosion in MDEA system

Fig. 7 Time-dependent corrosion rate at 0.05 M salt concentration

Journal of Materials Engineering and Performance

without the test salts, the surface of the sample was entirelycovered by corrosion products and SEM/EDS analysis revealedthat the corrosion products were composed basically of acontinuous layer of dense, crystalline iron carbonate (FeCO3)which gives protectiveness to the carbon steel surface thusreducing corrosion rate with time. In the presence of sodiumthiosulfate (Fig. 8b), there were two visible corrosion productlayers; a dense, crystalline inner layer and a loose outer layer.From results of EDS analysis (Table 3), the inner layer ischaracterized by the presence of FeCO3, while the outer layermay be a sulfur-based product layer, which could have resultedfrom (a) disproportionation reaction of thiosulfate to yieldsulfide (Ref 24, 33) or (b) oxidation of thiosulfate to sulfate.This sulfur-based outer product layer is possibly responsible forthe inhibitive behavior of thiosulfate as it further extends theprotectiveness of the carbon steel surface. For Fig. 8(c), a thinfilm (tarnish) was visibly present on the carbon steel surfaceupon retrieval from the solution with sodium sulfide. On SEManalysis, this film appeared to be finely placed above the metalsurface with visible polishing marks indicating an excellentprotectiveness against anodic dissolution. EDS analysis re-vealed the presence of iron (Fe), carbon (C), oxygen (O) andsulfur (S) to be the composition of the corrosion products in thesystems with sodium thiosulfate and sodium sulfide as depictedin Table 3. This indicates that some sulfur-based passive layersare formed on the metal surfaces which will give an additionalinhibition to corrosion. An attempt was made to explore the useof XRD technique to evaluate and confirm the corrosion

product formed on the surface of the carbon steel specimen, butthe results were not meaningful enough for presentation. It istherefore possible that the corrosion products are either notpresent in crystalline forms or they exist in very minutequantities. Hence, XRD technique appears not to be appropriatefor studies of carbon steel immersed in both systems.

3.5 Corrosion Process and the Effect of Thiosulfate andSulfide Additions

The gas loading potentially caused a decrease in the pH of50 wt.% MDEA solution at 50 �C from 11.20 recorded for thesolution without gas to 9.13 for the gas-loaded solution. This isthe direct consequence of the formation of carbonic acidaccording to the equation:

CO2 þ H2O $ H2CO3 ðEq 5Þ

The addition of sodium thiosulfate and sodium sulfidefurther decreased the solution pH to 8.95 and 8.93, respectively.This is because the anions S2O3

2� and S2� are acid radicals ofbinary acids.

In the study of carbon steel in aqueous CO2-saturatedMDEA systems, the presence of dissolved CO2 has beenreported to be the primary corroding agent (Ref 34); therefore,the predominant corrosion product is the formation of iron (II)carbonate (FeCO3). Carbon steel materials exhibit low corro-sion rates due to the formation of this FeCO3 protective layer(Ref 35). A summary of the corrosion process is as shown:

Fig. 8 SEM images and their corresponding EDS analysis for carbon steel surface after 7 days immersion in MDEA solution with (a) no salt(b) 0.05 M sodium thiosulfate and (c) 0.05 M sodium sulfide

Table 3 Elemental composition (wt.%) of carbon steel surface after 7 days immersion in MDEA systems

System C K O K S K Fe K

Solution without salt 14.15 37.96 47.88Solution with 0.05 M sodium thiosulfate 12.91 5.91 4.58 76.60Solution with 0.05 M sodium sulfide 8.90 1.76 2.49 86.85

Journal of Materials Engineering and Performance

Iron dissolution:

Fe ! Fe2þ þ 2e� ðEq 6Þ

Reduction of bicarbonate ion:

2HCO�3 þ 2e� $ 2CO2�

3 þ H2 ðEq 7Þ

Overall reaction:

Fe2þ þ HCO�3 $ FeCO3 þ Hþ ðEq 8Þ

3.5.1 Effect of Thiosulfate Addition. Sodium thiosulfateaddition led to a reduction in corrosion rate of carbon steel asshown by electrochemical measurements and confirmed byweight loss test. Since the disproportionation reaction ofthiosulfate yields sulfide, it may have been possible that sulfidewas generated in the system and the sulfide may have furtherreacted with Fe2+ to form iron sulfide which could be a part ofthe composition of the loose outer layer as shown:

S2O2�3 þ H2O $ SO2�

4 þ HS� þ Hþ ðEq 9Þ

Fe2þ þ S2� ! FeS ðEq 10Þ

The thiosulfate may have also acted as a reducing agentwhere it can be oxidized to sulfate, in which case, the outercorrosion layer may possibly contain a sulfate compound:

S2O2�3 þ 2O2 þ H2O $ 2SO2�

4 þ 2Hþ ðEq 11Þ

SEM/EDS analysis suggests that the formation of an outerlayer of sulfur-based film was responsible for the extension ofprotectiveness on the surface of carbon steel.

3.5.2 Effect of Sulfide Addition. The polarization curvesand impedance spectra of carbon steel obtained at eachconcentration from potentiodynamic polarization and EISmeasurements, respectively, were consistent with the under-standing that the inhibition effect of sodium sulfide on CO2

corrosion of carbon steel was due to the formation of aprotective film of iron sulfides (Fig. 8) as described by Eq 10.The results are in agreement with existing findings as reportedby Choi et al. (Ref 36) where addition of H2S induced a rapidreduction in the CO2 corrosion rate of carbon steel in acidicsolutions by the formation of a thin iron sulfide (FeS) film. Asexplained by Nesic et al. (Ref 37), the FeS layer exhibits twodistinct and opposite effects on carbon steel corrosion; firstly,the layer inhibits the corrosion process at low sulfide concen-tration proportional to the film surface coverage but have littleor no effect on the movement of electrons through the film tocontinue the cathodic reactions. Secondly, it accelerates thecorrosion process at higher sulfide concentrations, by possiblyencouraging cathodic reactions with increased surface area.

Additional inhibition effects may have been imparted by thereducing property and oxygen scavenging ability of sodiumsulfide. However, these may be the secondary effects as sulfideis usually consumed quickly in the presence of oxygen (Ref38).

4. Conclusions

The corrosion behavior of carbon steel has been evaluated ina CO2-saturated MDEA system containing sodium thiosulfateand sodium sulfide by the use of electrochemical methods,

weight loss measurements and surface analytical techniques,and it was concluded that:

1. Sodium thiosulfate showed corrosion inhibitive behaviorsfor carbon steel. This was possible because of the extraprotectiveness added by the formation of a loose outerfilm layer which was identified to be a sulfur-based pro-duct layer by SEM/EDS analysis.

2. Sodium sulfide also caused a reduction in the corrosionrate of carbon steel by the formation of a thin film (tar-nish) which could possibly be FeS which impeded theacceleration of metal dissolution reaction. The reducingproperty and oxygen scavenger ability of sodium sulfidemay have been secondary factors for its inhibitive ac-tions.

3. The values of polarization resistance, Rp, of carbon steelincreased steadily with sodium thiosulfate concentration,while for sodium sulfide, the inhibition was at maximumfor the least concentration (0.05 M), and its value de-creased with increasing concentration.

4. Comparative evaluation of carbon steel corrosion byweight loss measurements after 7 days immersion periodin MDEA systems with the absence and presence of0.05 M sodium thiosulfate and 0.05 M sodium sulfide re-vealed that carbon steel achieved a better corrosion resis-tance in the system with sodium sulfide with aninhibition efficiency of 96.7% compared to an inhibitionefficiency of 91.3% recorded for sodium thiosulfate.

References

1. J.C.M. Pires, F.G. Martins, M.C.M. Alvim-Ferraz, and M. Simoes,Recent Developments on Carbon Capture and Storage: An Overview,Chem. Eng. Res. Des., 2011, 89(9), p 1446–1460

2. M. Wang, A. Lawal, P. Stephenson, J. Sidders, and C. Ramshaw, Post-Combustion CO2 Capture with Chemical Absorption: A State-of-the-Art Review, Chem. Eng. Res. Des., 2011, 89(9), p 1609–1624

3. S. Rennie, Corrosion and Materials Selection for Amine Service,Mater. Forum, 2006, 30, p 126–130

4. M. Howard and A. Sargent, Texas Gas Plant Faces Ongoing Battle-With Oxygen Contamination, Oil Gas J., 2001, 99(30), p 52

5. A. Keller, N. Hatcher, in Amine Sampling/Laboratory Technique andits Effects on H2S Loading Measurements, Laurance Reid GasConditioning Conference, 2005, pp 85–93

6. L. Dumee, C. Scholes, G. Stevens, and S. Kentish, Purification ofAqueous Amine Solvents Used in Post Combustion CO2 Capture: AReview, Int J Greenh Gas Con, 2012, 10, p 443–455

7. M.S. DuPart, P.C. Rooney, and T.R. Bacon, Comparing Laboratory andPlant Data for MDEA/DEA Blends, Hydrocarb Process, 1999, 78(4), p81–86

8. H. Lepaumier, S. Martin, D. Picq, B. Delfort, and P.L. Carrette, NewAmines for CO2 Capture. III. Effect of Alkyl Chain Length BetweenAmine Functions on Polyamines Degradation, Ind. Eng. Chem. Res.,2010, 49(10), p 4553–4560

9. H. Lepaumier, D. Picq, and P.L. Carrette, New Amines for CO2

Capture. I. Mechanisms of Amine Degradation in the Presence of CO2,Ind. Eng. Chem. Res., 2009, 48(20), p 9061–9067

10. H. Lepaumier, D. Picq, and P.L. Carrette, New Amines for CO2

Capture. II. Oxidative Degradation Mechanisms, Ind. Eng. Chem. Res.,2009, 48(20), p 9068–9075

11. S. Martin, H. Lepaumier, D. Picq, J. Kittel, T. de Bruin, A. Faraj, andP.L. Carrette, New Amines for CO2 Capture. IV. Degradation,Corrosion, and Quantitative Structure Property Relationship Model,Ind. Eng. Chem. Res., 2012, 51(18), p 6283–6289

Journal of Materials Engineering and Performance

12. C.J. Smit, G.J. Van Heeringen, Van Grinsven P.F.A., in Degradation ofAmine Solvents and Therelation with Operational Problems, LauranceReid Gas Conditioning Conference, 2002, pp 197–212

13. B.C. Friedman, in Understanding the Basics of Corrosion in Sweet andSour Gas Treating Plants, Laurance Reid Gas Conditioning Confer-ence, 2005, pp 183–205

14. M. Nainar and A. Veawab, Corrosion in CO2 Capture Process UsingBlended Monoethanolamine and Piperazine, Ind Eng Chem Res, 2009,48(20), p 9299–9306

15. T. Nguyen, M. Hilliard, and G.T. Rochelle, Amine Volatility in CO2

Capture, Int J Greenh Gas Con, 2010, 4(5), p 707–71516. G.T. Rochelle, Thermal Degradation of Amines for CO2 Capture, Curr

Opin Chem Eng, 2012, 1(2), p 183–19017. S.M. Cohen, G.T. Rochelle, M.E. Webber, in Optimal operation of

flexible post-combustion CO2 capture in response to volatile electricityprices, 10th International Conference on Greenhouse Gas ControlTechnologies, 4, 2604–2611 (2011) (in English)

18. Q. Xu, G. Rochelle, in Total Pressure and CO2 solubility at hightemperature in aqueous amines, 10th International Conference onGreenhouse Gas Control Technologies, vol 4, pp 117–124 (2011)

19. A. Veawab, P. Tontiwachwuthikul, and A. Chakma, Influence ofProcess Parameters on Corrosion Behavior in a Sterically HinderedAmine-CO2 System, Ind. Eng. Chem. Res., 1999, 38(1), p 310–315

20. D. Duan, Y.S. Choi, S. Nesic, F. Vitse, S.A. Bedell, and C. Worley,Effect of Oxygen and Heat Stable Salts on the Corrosion of CarbonSteel in MDEA-Based CO2 Capture Process, Corrosion/2010, PaperNo. 10191, NACE, San Antonio, Texas, 2010

21. S.A. Freeman, J. Davis, and G.T. Rochelle, Degradation of AqueousPiperazine in Carbon Dioxide Capture, Int J Greenh Gas Con, 2010,4(5), p 756–761

22. P.C. Rooney, Dupart, M. S., Bacon, T.R., Oxygen�s Role inAlkanolamine Degradation. Hydrocarbon Processing (InternationalEdition), 77(7), (1998)

23. W. Tanthapanichakoon, A. Veawab, in Heat Stable Salts and Corro-sivity in Amine Treating Units, ed by J.G. Kaya. Greenhouse gascontrol technologies—6th International Conference (Pergamon, 2003),p 1591–1594

24. S. Srinivasan, A. Veawab, and A. Aroonwilas, Low Toxic CorrosionInhibitors for Amine-Based CO2 Capture process, Enrgy Proced, 2013,37, p 890–895

25. H. Ma, X. Cheng, G. Li, S. Chen, Z. Quan, S. Zhao, and L. Niu, TheInfluence of Hydrogen Sulfide on Corrosion of Iron Under DifferentConditions, Corros. Sci., 2000, 42(10), p 1669–1683

26. E. Abelev, T.A. Ramanarayanan, and S.L. Bernasek, Iron Corrosion inCO2/Brine at Low H2S Concentrations: An Electrochemical andSurface Science Study, J. Electrochem. Soc., 2009, 156(9), p C331–C339

27. D.W. Shoesmith, P. Taylor, M.G. Bailey, and D.G. Owen, TheFormation of Ferrous Monosulfide Polymorphs During the Corrosionof Iron by Aqueous Hydrogen-Sulfide at 21-Degrees-C, J. Elec-trochem. Soc., 1980, 127(5), p 1007–1015

28. W. Sun, S. Nesic, and S. Papavinasam, Kinetics of Corrosion LayerFormation. Part 2—Iron Sulfide and Mixed Iron Sulfide/CarbonateLayers in Carbon Dioxide/Hydrogen Sulfide Corrosion, Corrosion,2008, 64(7), p 586–599

29. ASTM Standard G31-72, Standard Practice of Laboratory ImmersionCorrosion Testing of Metals, ASTMed., 2004

30. K. Juttner, Electrochemical Impedance Spectroscopy (EIS) of Corro-sion Processes on Inhomogeneous Surfaces, Electrochim. Acta, 1990,35(10), p 1501–1508

31. D.A. Lopez, S.N. Simison, and S.R. de Sanchez, Inhibitors Perfor-mance in CO2 Corrosion: EIS Studies on the Interaction Between theirMolecular Structure and Steel Microstructure, Corros. Sci., 2005,47(3), p 735–755

32. C.N. Cao and J.Q. Zhang, An Introduction to ElectrochemicalImpedance Spectroscopy, Science Press, Beijing, 2002

33. W.A. Pryor, The Kinetics of the Disproportionation of SodiumThiosulfate to Sodium Sulfide and Sulfate, J. Am. Chem. Soc., 1960,82(18), p 4794–4797

34. A. Veawab, P. Tontiwachwuthikul, and S.D. Bhole, Studies ofCorrosion and Corrosion Control in a CO2-2-Amino-2-methyl-1-Propanol (AMP) Environment, Ind. Eng. Chem. Res., 1997, 36(1), p264–269

35. S. Sim, I.S. Cole, Y.S. Choi, and N. Birbilis, A Review of theProtection Strategies Against Internal Corrosion for The Safe Transportof Supercritical CO2 Via Steel Pipelines for CCS Purposes, Int JGreenh Gas Con, 2014, 29, p 185–199

36. Y.S. Choi, S. Nesic, and S. Ling, Effect of H2S on the CO2 Corrosionof Carbon Steel in Acidic Solutions, Electrochim. Acta, 2011, 56(4), p1752–1760

37. S. Nesic, J.Y. Cai, and K.J. Lee, A Multiphase Flow and InternalCorrosion Prediction Model for Mild Steel Pipelines, Corrosion/2005,Paper No. 05556, NACE, Houston, Texas, 2005

38. K. Fuseler and H. Cypionka, Elemental Sulfur as an Intermediate ofSulfide Oxidation with Oxygen by Desulfobulbus-Propionicus, Arch.Microbiol., 1995, 164(2), p 104–109

Journal of Materials Engineering and Performance