International Research Journal of Environment Sciences________________________________ ISSN 2319–1414Vol. 1(5), 14-21, November (2012) Int. Res. J. Environment Sci. International Science Congress Association 14 Asafoetida Extract (ASF) as green Corrosion Inhibitor for Mild Steel in Sea Water Sangeetha M., Rajendran S.1,3, Sathiyabama J. and Prabhakar P.2 Department of Chemistry, GTN Arts College, Dindigul Tamil Nadu, INDIA Department of Chemistry, APA College for Arts and Culture Palani, INDIA Department of Chemistry, RVS School of engineering and Technology, Dindigul, Tamil Nadu, INDIAAvailable online at: www.isca.in Received 10th October 2012, revised 20th October 2012, accepted 13th November 2012 Abstract An aqueous extract of asafoetida has been used as a corrosion inhibitor in controlling corrosion of carbon steel. The main constituent of this extract is umbelliferone. It has excellent inhibition efficiency (IE) of 98% at Zn2+ (25 ppm) by the weight loss method. The protective film has been analyzed using Atomic Force Microscopic (AFM) and FTIR spectroscopic techniques. Protective film formed on the metal surface is confirmed by using Electro chemical studies such as potentiodynamic polarization technique. Polarization study reveals that this system functions as mixed type of inhibitor. Key words: Carbon steel, inhibition efficiency, umbelliferone, AFM; green inhibitors, protective film. Introduction So many natural products are used for analyzing antimicrobial1,2,3, antifungal, anticancer, antibacterial activityin several areas. Nowadays need for growing corrosion inhibitors becomes increasingly necessary to stop or delay the attack of a metal in an aggressive solution. Considerable efforts are made to find suitable compounds to be used as corrosion inhibitors in various corrosive media. Many works were conducted to examine extracts from naturally substances. So in this work we have taken natural product as our corrosion inhibitor. Some references are coated here in which natural products are used as corrosion inhibitor. Corrosion inhibition of carbon steel in low chloride media by an aqueous extract of Hibiscus rosa - sinensis Linn has been evaluated by mass – loss method and electrochemical studies, corrosion inhibition by beet root extract in well water, electrochemical studies confirm the formation of a protective film on the metal surface by spirulina solution, this offers 90% corrosion inhibition efficiency corrosion resistance of metals inartificial saliva in the absence and also in the presence of spirulina, corrosion behavior of aluminium in various media has been used to control corrosion of aluminium. To prevent the corrosion of aluminium in acid medium, inhibitors such as Chlomolaena Odorata L.10, Ananas Sativum11, Ipomoea Invulcrata12. There are several reviews on the use of plant extracts as corrosion inhibitors13.Recently aqueous extract of Cocos nucifera - Coconut Palm – Petiole14. Fennel (Foeniculum Vulgare) Essential15. Pericarp of the Fruit of Garcinia Mangostana16. Natural17. Ethanol extract of Vernonia Amygdalina18 and Ipomoea involcrata19 have been used as corrosion inhibitors. Langmuir adsorption isotherm proved the effects of Alovera on corrosion of Zinc in HCl solution20, in the presence of fruit peel in hydrochloric acid on carbon steel21, and it also proved that Murraya Koenigii acts as corrosion inhibitor on mild steel in hydrochloric acid and sulphuric acid solutions22, investigation of natural inhibitors is particularly interesting because they are non –expensive, ecologically friendly acceptable and possess no threat to the environment. Asafoetida is an ingredient of a plant mixture reported to have antidiabetic properties in rats23, Asafoetida has a broad range of uses in traditional medicine as an antimicrobial, antiepileptic, used for treating chronic bronchitis and whooping cough24,25. The present work is undertaken: i. To evaluate the inhibition efficiency (IE) of an aqueous extract of asafotida (ASF) in controlling the corrosion of carbon steel in sea water, in the absence and presence of Zn2+ ii. To investigate the influence of immersion period on the IE of the system. iii. To analyze the protective film formed on the carbon steel by FTIR spectra, Polarization study and Atomic Force Microscope techniques. Material and Methods Preparation of the specimen: Carbon steel specimens of size 1.0 cm × 4.0 cm × 0.2 cm and chemical composition 0.026 % sulphur, 0.06 % phosphorous, 0.4 % manganese, 0.1 % carbon and the rest iron were polished to a mirror finish and degreased with trichloroethylene and used for the weight loss method and surface examination studies. Preparation of umbelliferone asafoetida extract: An aqueous extract of umbelliferone asafoetidawas prepared by grinding 5g of asafoetida, with distilled water, filtering the suspending impurities, and making up to 100 ml. The extract was used as corrosion inhibitor in the present study. International Research Journal of Environment Sciences______________________________________________ ISSN 2319–1414 Vol. 1(5), 14-21, November (2012)Int. Res. J. Environment Sci. International Science Congress Association 15 Weight-loss method: Carbon steel specimens were immersed in 100 ml of the sea water in [Nagarkovil, Tamil nadu, India] containing various concentrations of the inhibitor asafotida (ASF) in the absence and presence of Zn2+ for one day. The weights of the specimens before and after immersion were determined using a Digital Balance (Model AUY 220 SHIMADZU). The corrosion inhibition efficiency (IE) was then calculated using the equation IE = 100 [1-(W/W)] % Where W is the weight loss value in the absence of inhibitor and W is the weight loss value in the presence of inhibitor. Surface examination study: The carbon steel specimens were immersed in various test solutions for a period of 1 day. After 1 day, the specimens were taken out and dried. The nature of the film formed on the surface of the metal specimen was analyzed by various surface analysis techniques. Fourier transform infrared spectra: These spectra were recorded in a Perkin-Elmer-1600 spectrophotometer using KBr pellet. The FTIR spectrum of the protective film was recorded by carefully removing the film, mixing it with KBr and making the pellet. Atomic Force Microscopy characterization (AFM): The carbon steel specimen immersed in blank and in the inhibitor solution for a period of one day was removed, rinsed with double distilled water, dried and subjected to the surface examination. Atomic force microscopy (Veeco dinnova model) was used to observe the samples’ surface in tapping mode, using cantilever with linear tips. The scanning area in the images was 5 m × 5 m and the scan rate was 0.6 HZ /second. Potentiodynamic Polarization: Polarization studies were carried out in a CHI- electrochemical work station with impedance model 660A. It was provided with iR compensation facility. A three electrode cell assembly was used. The working electrode was carbon steel. A SCE was the reference electrode. Platinum was the counter electrode. From polarisation study, corrosion parameters such as corrosion potential (Ecorr), corrosion current (Icorr), Tafel slopes anodic = b and cathodic = were calculated and polarization study was done. The scan rate (V/S) was 0.01. Hold time at (Efcs) was zero and quiet time (s) was two. Table-1 Parameters of Sea water [Nagarkovil, Tamil nadu, India] parameters Value pH 7.4 Electrical conductivity 58564 micS/cm Total disolved soilds 39824 ppm Total Hardness 112 ppm Magnesium 14 ppm Calcium 21 ppm Chloride 18350 ppm Sulphate 4354 ppm Analysis of results of weight - loss study: The calculated Inhibition efficiencies (IE) and corresponding corrosion rates of asafoetida (ASF) in controlling the corrosion of carbon steel immersed in the presence and absence of Zn2+ have been tabulated in table-2 It is observed that asafoetida only shows good inhibition efficiency (IE) (in the absence of Zn2+). When Zn2+ (5 ppm) is added IE also increases .IE increases and gives maximum 98 % IE at 4 ml of ASF and 25 ppm of Zn2+ this shows that synergistic effect exists between Zn2+ and the active principles present in ASF. When the concentration of Zn2+ increases from 5 ppm to 25 ppm the IE slightly decreases. This may be due to the fact that, when the concentration of Zn2+ increases, the Zn2+ASF complex formed is precipitated in the bulk of the solution. Hence ASF is not transported towards the metal surface. So the IE decreases,similar observation was made with Hibiscus Rosa-Sinensis Al at pH 1226 Euphorbia27 Henna28. Table-2 Corrosion rates (CR) and inhibition efficiency of carbon steel immersed in an aqueous solution in The absence and presence of inhibitors ASF ( ml) IE%CR mm/y Zn 2+ (ppm)Zn 2+ (ppm) 0 5 15 25 0 5 15 25 0 -- 20 25 30 0.1623 0.1298 0.1217 0.1136 2 60 54 54 88 0.0649 0.0746 0.0746 0.0194 4 65 62 60 98 0.0568 0.0616 0.0649 0.0032 6 71 65 65 94 0.0470 0.0568 0.0568 0.0097 8 71 77 82 88 0.0470 0.0373 0.0292 0.0194 Inhibitors :asafoetida (ASF) + Zn2+ .Period of immersion : 1 day International Research Journal of Environment Sciences______________________________________________ ISSN 2319–1414 Vol. 1(5), 14-21, November (2012)Int. Res. J. Environment Sci. International Science Congress Association 16 Table-3 Influence of duration of immersion on the inhibition efficiency of ASF-Zn2+ system Immersion period, day 1 3 5 7 CR in the absence of the Inhibitor, mdd 0.1623 0.3153 0.4545 0.6214 CR in the presence of the inhibitor, ASF (4ml) +Zn 2+ (25 ppm) 0.0032 0.1387 0.2999 0.4598 IE, % 98 56 34 26 Influence of immersion period on the inhibition efficiency of ASF: The influence of duration of immersion on the IE of ASF (4ml) – Zn2+ (25ppm) system is given in table-3.When the immersion period increases the inhibition efficiency decreases and the corrosion rate increases. This shows that the protective film formed on the metal surface, was broken by the corrosive environment and the film was dissolved, this same result is shown in Phyllanthus amarus extract29, it is observed that in phyllanthus amarus as the duration of immersion increases the IE decreases. Results and Discussion The physicochemical parameters of Sea water are given in table-1. Analysis of FTIR spectra: Earlier researchers have confirmed that FTIR spectrometer is a powerful instrument that can be used to determine the type of bonding for organic inhibitors adsorbed on the metal surface30. FTIR spectra have been used to analyze the protective film formed on metal surface. FTIR spectrum of pure dried Asofoetida ASF is given in figure-1a. The FTIR spectrum of the film formed on the metal surface after immersion in the sea water for 1 day containing 4ml of ASF and 25 ppm of Zn2+ is shown in Fig-1b. The OH stretching frequency has increased from3407 cm-1 to 3425 cm-1,C=O stretching frequency has shifted from 1630 cm-1 to 1634cm-1, ring O stretching frequency has increased from 1039 cm-1 to 1056 cm-131. The band due to conjugated double bonds shifts from 3785 cm-1 to 3751 cm-1.This indicates that the oxygen atom of C=O group has coordinated with Fe2+ formed on the metal surface resulting in the formation of Fe2+- ASF complex on the metal surface. The peak at 1376 cm is due to Zn(OH) formed on the cathodic sites of the metal surface29. The active principle in an aqueous extract of asafotida is (umbelliferone) this figure is shown in scheme:1. umbelliferone Scheme :1 Figure-1a FTIR spectrum of pure dried ASF Figure-1b FTIR spectrum of the film formed on the metal surface after immersed in the sea water containing 4ml of ASF and 25 ppm of Zn2+Atomic Force Microscopy Characterization: AFM is a powerful technique to investigative the surface morphology at nano- to micro-scale and has become a new choice to study the influence of inhibitor on the generation and the progress of the corrosion at the metal/solution interface32-35. The three dimensional (3D) AFM morphologies and the AFM crosssectional profile for polished carbon steel surface (reference sample), carbon steel surface immersed in sea water (blank 4000.03000200015001000 400.0 0.0102030405060708090100.0cm-1%T 3929.10 3785.67 3407.55 2923.77 2131.12 1630.41 1424.53 1374.61 1237.41 1039.82 765.86 706.69 572.10 4000.03000200015001000400.00.0102030405060708090100.0cm-1%T 3958.54 3849.75 3751.30 3425.36 2990.05 2891.48 2782.80 2676.46 2566.97 2463.37 2394.93 2075.05 1634.57 1376.25 1238.92 1056.50 596.35 International Research Journal of Environment Sciences______________________________________________ ISSN 2319–1414 Vol. 1(5), 14-21, November (2012)Int. Res. J. Environment Sci. International Science Congress Association 17 sample) and carbon steel surface immersed in sea water containing the formulation of 4ml of BPE and 15 ppm of Zn2+ are shown as figure-2 images (a, d,), (b, e,), (c, f,) respectively. Root– mean-square roughness, average roughness and peak-to-valley value AFM image analysis was performed to obtain the average roughness, Ra (the average deviation of all points roughness profile from a mean line over the evaluation length), root-mean-square roughness, Rq (the average of the measured height deviations taken within the evaluation length and measured from the mean line) and the maximum peak-to-valley (P-V) height values (largest single peak-to-valley height in five adjoining sampling heights)33. (a) (b)(c) Figure-2 Three dimensional AFM images of the surface of: a) As polished carbon steel(control); b) carbon steel immersed in sea water (blank); c) carbon steel immersed in sea water containing ASF (4ml) + Zn2+ (25ppm) (d) International Research Journal of Environment Sciences______________________________________________ ISSN 2319–1414 Vol. 1(5), 14-21, November (2012)Int. Res. J. Environment Sci. International Science Congress Association 18 (e) (f) Figure-2 AFM cross-sectional images of the surface of: d) As polished carbon steel (control); e) carbon steel immersed in sea water (blank); f) carbon steel immersed in sea water containing ASF (4ml) + Zn2+ (25ppm) Table-4 is a summary of (Rq), (Ra), (P-V) value for carbon steel surface immersed indifferent environment. Figure-2 (a, d,) displays the surface topography of un-corroded metal surface. The value of Rq, Ra and P-V height for the polished carbon steel surface (reference sample) are 4.3 nm, 3.41nm and 35.28 nm respectively. The slight roughness observed on the polished carbon steel surface is due to atmospheric corrosion. Figure- 2(b, e,) displays the corroded metal surface with few pits in the absence of the inhibitor immersed in sea water. The (Rq), (Ra), (P-V) height values for the carbon steel surface are 25.2nm, 19.9nm and 89.10 nm respectively. These data suggests that carbon steel surface immersed in sea water has a greater surface roughness than the polished metal surface, which shows that the unprotected carbon steel surface is rougher and was due to the corrosion of the carbon steel in sea water environment. Figure-2 (c, f,) displays the steel surface after immersion in sea water containing 4ml of ASF and 25 ppm of Zn2+ . The (Rq), (Ra), (P-V) height values for the carbon steel surface are 6.38nm, 4.72nm and 14.81nm respectively The (Rq), (Ra), (P-V) height values are considerably less in the inhibited environment compared to the uninhibited environment. These parameters confirm that the surface is smoother. The smoothness of the surface is due to the formation of a compact protective film of Fe2+ - ASF complex thereby inhibiting the corrosion of carbon steel33. Analysis of polarization curve: The potentiodynamic polarization curves of carbon steel immersed in sea water in the absence and presence of inhibitors (Asafotida extract (ASF) and Zn2+) are shown in figure-3. The corrosion parameters namely corrosion potential (Ecorr), Tafel slopes (b = cathodic b = anodic), linear polarization resistance (LPR) and corrosion current (Icorr) are given in table-5. It is observed that in the absence of inhibitors the corrosion potential is-771 mV vs SCE. In the presence of inhibitors ( 4ml ASF and 25 ppm Zn2+) the corrosion potential is shifted to -765 mV vs SCE .The shift is very small this suggests that this formulation controls the anodic reaction and cathodic reaction to an equal extant . So we can conclude that this inhibitor acts as mixed type of inhibitor .The LPR value increases from 2378 ohm cm to 5664 ohm cmfurther the corrosion current decreases from 1.579 x10-5 A/cmto 0.6832x10-5 A/cm .This suggests that a protective film is formed on the metal surface36-40. Figure-3 Polarization curves of carbon steel immersed in various test solutions (a) sea water (blank); (b) ASF (4ml) + Zn2+ 25 ppm International Research Journal of Environment Sciences______________________________________________ ISSN 2319–1414 Vol. 1(5), 14-21, November (2012)Int. Res. J. Environment Sci. International Science Congress Association 19 Table-4 AFM data for carbon steel surface immersed in inhibited and uninhibited environment. Samples RMS(Rq) Roughness (nm) Average(Ra Roughness (nm) Maximum Peak-to valley Height (nm) 1.Polished carbon steel 4.33 3.41 35.28 2.Carbon steel immersed in sea water (blank) 25.2 19.9 89.10 3.Carbon steel immersed in sea water + ASF (4ml) + Zn 2+ (25ppm) 6.38 4.72 14.81 Table5 Corrosion parameters of carbon steel immersed in Asafotida extract obtained from polarization study. System corr mV vs SCE c mV/decade mV/decade LPR ohm cmI corrA/cm Sea water(blank) -771 160 186 2378 1.579x10 - 5 ASF(4ml)+ Zn 2+ (25ppm) -765 148 222 5664 0.6832x10 - 5 Conclusion The present study leads to the following conclusions. i. The formulation consisting of 4ml of ASF and 25 ppm of Zn2+ offers 98% inhibition efficiency to carbon steel immersed in sea water. ii. When immersion period increases corrosion rate also increases. iii. Polarization study reveals that this system formulation acts as a mixed type of inhibitor. iv. The FTIR spectra reveal that the protecting film consists of Fe2+-Asafotida (active ingredient) complex. v. AFM studies confirm that the surface is smoother. The smoothness of the surface is due to the formation of a compact protective film of Fe2+ - ASF complex on the metal surface thereby inhibiting the corrosion of carbon steel. Acknowledgement The authors are thankful to their management and UGC India for their help and encouragement. References 1.Mangale Sapana M., Chonde Sonal G. and Raut P.D., Use of Moringa Oleifera (Drumstick) seed as Natural Absorbent and an Antimicrobial agent for Ground water Treatment Res.J.Recent Sci.,1(3), 31-40 (2012) 2.Sinha Kanak and Verma Anita K., Evaluation of Atimicrobial and Anticancer activities of Methanol Extract of in vivo and in vitro grown Bauhinia variegate L. I.Res.j.Biological Sci.,1(6), 26-30 (2012) 3.Hegde Chaitra R., Madhuri M., Swaroop Nishitha T., Das Arijit., Bhattacharya Sourav and Rohit K.C., Evaluation of Antimicrobial Properties, Phytochemical Contents and Antioxidant Capacities of Leaf Extracts of Punica grantum L. ISCA J. Biological Sci.,1(2), 32-37 (2012) 4.Sessou Philippe, Farougou Souabou, Azokpota Paulin, Youssao Issaka and Sohounhlou Dominique, In vitro Antifungal activities of Essential oils extracted from Fresh Leaves of Cinnamomum zeylanicum and Ocimum gratissimum against Foodborne pathogens for their use as Traditional Cheese Wagashi conservatives. Res.J.Recent Sci.,1(9), 67-73 (2012) 5.Masih Usha, Shrimali R. and Nagvi S.M.A., Antibacterial Activity and Ethanol Extracts of Cinnamon (Cinnamomum Zeylanicum) and Ajowan (Trachyspermum ammi) on four food Spoilage Bacteria I.Res.J.Biological Sci., 1(4), 7-11 (2012) 6.Anuradha K., Vimala R., Narayanasamy B., Arockia Selvi J., Rajendran S., Corrosion inhibition of carbon steel in low chloride media by an aqueous extract of Hibiscus rosa –sinensis Linn, Chem Eng Comm., 195-352 (2008)7.Arockia Selvi J., Susai Rajendran, Ganga sri V., John Amalraj A., Narayanasamy B., Corrosion inhibition by Beet Root extract, Portugaliae Electrochemica Acta. 27 (1), 1-11 (2009)8.Sumithra P., Shyamala Devi B., Jeyasundari J., Corrosion inhibition by Spirulina, Zastita Materijala,50, 223-226 (2009)9.Rajendran S., Paulraj J., Rengan P., Jeyasundari J. and Manivannan M., Corrosion behavior of metals in artificial saliva in presence of spirulina powder, Journal of Dentistry and Oral Hygiene1(1), 001-008 (2009)10.Obot I.B., Obi Egbedi N.O., An interesting and efficient green corrosion inhibitor for aluminium from extracts of Chlomolaena Odorata L. in acidic solution, Journal of Electro Chemistry40(11), 1977-1984 (2010)11.Ating E.I., Umoren S.A., Udousors I.I., Ebenso E.E., Udon A.P., Leaves extract of ananas sativum as green corrosion inhibitor for aluminium in hydrochloric acid solutions, Green Chemistry Letters and Revies3(2), 61-68 (2010)12.Obot I.B., Obi Egbedi N.O., Umoren S.A., Ebenso E.E., Synergistic and antagonistic effects of anions and Ipomoea invulcrata as green corrosion inhibitor for aluminium dissolution in acidic medium, International Journal of Electrochemical science5(7), 994-1007 (2010) International Research Journal of Environment Sciences______________________________________________ ISSN 2319–1414 Vol. 1(5), 14-21, November (2012)Int. Res. J. Environment Sci. International Science Congress Association 20 13.Sangeetha M., Rajendran S., Muthumegala T.S., Krishnaveni A., Green corrosion inhibitors-An Overview, Zastita Materijala, 52, 3-19 (2011) 14.Vijayalakshmi P.R, Rajalakshmi R., Subhashini S., Corrosion Inhibition of Aqueous Extract of Cocos nucifera - Coconut Palm - Petiole Extract from Destructive Distillation for the Corrosion of Mild Steel in Acidic Medium, Port Electrochim Acta29(1), 9-21 (2011) 15.Lahhit N., BouyanzerA., Desjobert J.M.et al. Fennel (Foeniculum Vulgare) Essential Oil as Green Corrosion Inhibitor of Carbon Steel in Hydrochloric Acid Solution, Port Electrochim Acta29(2), 127-138 (2011) 16.Vinod Kumar K.P., Narayanan Pillai N.S., Rexin Thusnavis G., Pericarp of the Fruit of Garcinia Mangostana as Corrosion Inhibitor for Mild Steel in Hydrochloric Acid Medium, Port Electrochim Acta28(6) 373-383 (2010) 17.Bouyanzer A., Hammouti B., Majidi L.,et al. Testing Natural Fenugreek as an Ecofriendly Inhibitor for Steel Corrosion in 1 M HCl, Port Electrochim Acta28(3), 165- 172 (2010) 18.Odiongenyi A.O., Odoemelam S.A., Eddy N.O., Corrosion inhibition and adsorption properties of ethanol extract of Vernonia Amygdalina for the corrosion of mild steel in SO, portugaliae Electrochimica Acta,27(1), 33-45 (2009) 19.Obot I.B., Obi-Egbedi N.O., Ipomoea involcrata as an ecofriendly inhibitor for aluminium in alkaline medium, Portugaliae Electrochimica Acta27(4), 517-524 (2009)20.Aboia O.K., James A.O., The effects of Aloevera rxtract on corrosion and kinetics of corrosion process of zinc in HCl solution. Corrosion Science52(2), 661-664 (2010)21.Janaina Cardozo da Rocha, Jose Antonio da Cunha PoncianoGomes, Eliane D Elia, Corrosion inhibition of carbon steel in hydrochloric acid solution by fruit peel aqueous extract, Corrosion Science52(7), 2341-2348 (2010)22.Quraishi M.A., Singh A., Singh V.K., Yadav D.K., Singh A.K., Green approach to corrosion inhibition of mild steel in hydrochloric acid and sulphuric acid solutions by the extract of Murraya koenigii leaves, Materials chemistry and Physics 122(1), 114-122 (2010) 23.Al-Awadi FM et al. On the mechanism of the hypoglycaemic effect of a plant extract, Diabetologia, 28,432-434 (1985) 24.Srinivasan K.,Role of Spices Beyond Food Flavoring: Nutraceuticals with Multiple Health Effects, Food Reviews International, 21(2), 167–188 (2005) 25.Abdin M.Z. and Abdin Y.P., Abrol. Published Alpha Science Int'l Ltd. Traditional Systems of Medicine, ISBN 81-7319-707-5(2006)26.Rajendran S., Jeyasundari J., Usha P., Selvi J.A., Narayanasamy B., Regis A.P.P., Rengan P., Corrosion behavior of aluminium in the presence of an aqueous extract of Hibiscus rosa–sinensis. Portugaliae Electrochemica Acta,27(2), 153-164 (2009)27.Kasthuri P.K., Arulanantham A., Ecofriendly extract of Euphobia hirta as corrosion inhibitor on mild steel in sulphuric acidmedium. Asian Journal of Chemistry,22(1),430-434 (2010)28.Rajendran S., Agasta M., Bama Devi R., Shyamala Devi B., Rajam K., Jeyasundari J., Corrosion inhibition by an aqueous extract of Henna leaves (Lawsonia Inermis L), Zastita Materijala50(2), 77-84 (2009)29.Sangeetha M., Rajendran S., Sathiyabama J., Krishnaveni A., Shanthy P., Manimaran N., Shyamaladevi B., Corrosion inhibition by an aqueous extract of phyllanthus amarus, Portugaliae Electrochimica Acta, 29(6), 429-444 (2011)30.Lalitha A., Ramesh S. , Rajeswari S., Electrochim. Acta, 51, 47–55 (2005) 31.Robert M. and Silverstein Francis X. Webster Spectrometric Identification of Organic Compounds, VI Edition, Wiley Student Editor:108 (2007)32.Satapathy A.K., Gunasekaran G., Sahoo S.C., Kumar Amit and Rodrigues P.V., Corrosion inhibition by Justicia gendarussa plant extract in hydrochloric acid solution. Corrosion science, 51(12), 2848-2856 (2009)33.Benita Sherine, Jamal Abdul Nasser A., Rajendran S., In J. Eng. Sci. and Technol, 24, 341-357 (2010)34.Singh Ashish Kumar and Quraishi M.A., Corros.Sci., 53,1288-1297(2011)35.Wang B., Du M., Zhang J., Gao C.J., Corros.Sci., 53, 353-361 (2011)36.Lebrini M., Robert F., Roos C., Inhibition effect of alkaloids extract from Annona Squamosa plant on the corrosion of C38 steel in normal hydrochloric acid medium. International Journal of Electrochemical Science5(11), 1698-1712 (2010)37.Saratha R., Vasudha V.G., Emblica Officinalis (Indian Gooseberry) leaves extract as corrosion inhibitor for mild steel in 1N HCl medium, E-Journal of chemistry,7 (3),677-684 (2010)38.Badiea A.M., Mohana K.N., corrosion mechanism of low- carbon steel in industrial water and adsorption thermodynamics in the presence of some plant extracts, International Research Journal of Environment Sciences______________________________________________ ISSN 2319–1414 Vol. 1(5), 14-21, November (2012)Int. Res. J. Environment Sci. International Science Congress Association 21 Journal of Materials Engineering and Performance, 18(9), 1264-1271 (2009)39.Raja P.B., Rahim A.A., sman H.O. and Awang K., Inhibitory effect of Kopsia singapurensis extract on the corrosion behavior of mild steel in acid media, Wuli Huaxue Xuebao/Acta Physico- Chimica Sinica, 26(8),2171-2176 (2010) 40.Sharmila A., Prema A.A, Sahayaraj P.A., Influence of Murraya koenigii(curry leaves) extract on the corrosion inhibition of carbon steel in HCl solution, Rasayan Journal of Chemistry3(1), 74-81 (2010)