IJCPE Vol.11 No.1 (March 2010) Iraqi Journal of Chemical and Petroleum Engineering Vol.11 No.1 (March 2010) 65-76 ISSN: 1997-4884 The Inhibition Effect of Peach Juice on Corrosion of Low Carbon Steel in Hydrochloric Acid at Different Temperatures Aprael S. Yaro * and Hadeel F. Ibraheem * Chemical Engineering Department - College of Engineering - University of Baghdad – Iraq Abstract The corrosion inhibition of low carbon steel in1N HCl solution in the presence of peach juice at temperature (30,40,50,and 60)°C at concentration ( 5, 10, 20, 30, 40and 50 cm3/L)were studied using weight loss and polarization techniques. Results show that the inhibition efficiency was increased with the increase of inhibitor concentration and increased with the increase of temperature up to 50ºC ,above 50ºC (i.e. at 60 ºC) the values of efficiency decreases. Activation parameters of the corrosion process such as activation energies, Ea, activation enthalpies, ∆H, and activation entropies, ∆S, were calculated. The adsorption of inhibitor follows Langmuir isotherm. Maximum inhibition efficiency obtained was a bout 91% at 50ºC in the 50 cm3/L inhibitor concentration. The polarization curves show that peach Juice is a mixed inhibitor. Keywords: low carbon steel, corrosion inhibition, peach juice, electrochemical method Introduction Corrosion inhibitors are widely used in industry to reduce the corrosion rate of metals and alloys in contact with aggressive environments. Most of the corrosion inhibitors are synthetic chemicals, expensive, and very hazardous to environments. Therefore, it is desirable to source for environmentally safe inhibitors [1-2]. There are some reports on the inhibition effects of non-toxic compounds on the corrosion of metals. We have recently reported the inhibition effect of amino acids on the steel [1] and aluminum [3] corrosion in acidic media. The inhibition effects of some non-toxic organic compounds have been also reported for steel corrosion [4, 5] but they are expensive. Metals and alloy are exposed to the action of acids in industry [6]. Processes in which acids play a vary important part are acid pickling, industrial acid cleaning, cleaning of oil refinery equipment, oil well acidizing and acid descaling[6,7]. The exposure can be most sever but in many cases. The aim of this study was to investigate the inhibition effect of peach Juice as a cheap, raw and non-toxic corrosion inhibitor on steel corrosion in hydrochloric acid. The electrochemical measurements were used to evaluate the inhibition efficiencies. In addition, the effect of temperature on inhibition behavior of the inhibitor was also studied. Experimental Work Materials and samples Peach juice Fully ripened peaches were purchased from a local market (Baghdad-Iraq) the fruits were washed in tap water and then mechanically compressed to obtain corresponding juice. The juice was then filtered to obtain a homogenous solution. In this process 300 ml peach juice from 1kg fresh was obtained. The extracted juice was kept frozen (< 00C) in glass bottles until farther experiment, the concentrations of inhibitor were chosen as5, 10, 20, 30,40and50 cm3/L Properties of peach juice: pH = 3.72 , Density = 1.078 g/ml University of Baghdad College of Engineering Iraqi Journal of Chemical and Petroleum Engineering The Inhibition Effect of Peach Juice on Corrosion of Low Carbon Steel in Hydrochloric Acid at Different Temperatures 66 IJCPE Vol.11 No.1 (March 2010) Low carbon steel The material of electrodes used was low carbon steel, of chemical composition (wt %) Experimental Procedure Weight loss Measurement The experiments were carried out using rectangular steel coupons, each of an area about 10.8 cm2, after polishing and cleaning, accurately weighed to the 4 decimal of gram before it used. Specimen was completely immersed in (250 ml) solution of corroding contained in (500 ml) beakers. They were exposed period of 2 hr, according to the test, at desired temperature and inhibitor concentration. After each test, the specimen was washed with running tap water, scrubbed with a brash to remove corrosion products, then washed with tap water followed by distilled water and dried by clean tissue immersed in acctone for 1 minute, dried, immersed in benzene for 1 minute dried and left in a desiccators over silica gel for 1hr. before weighting then accurately to the 4 th decimal and then reweighed. The weight loss was then determined and the rate of corrosion was expressed in (g/m2.hr). Electrochemical Measurements Half-cell measurements The change in potential of the working electrode as carbon steel was recorded as a function of time against saturated calomel electrode (SCE) which bridged by a luggin Haber probe. The “half cell” potential was carried directly on the display of voltmeter. Potentiostatic polarization measurements The data were obtained in three electrode mode. Graphite and saturated calomel electrodes were used as counter and reference electrodes respectively, the specimens used as working electrode. Corrosion cell parts were joined to each other, and then connected to a power supply, resistors, ammeter, and voltmeter, starting with cathodic polarization until reaching the corrosion potential then continuing with anodic polarization Results and Discussion Weight loss technique Corrosion rate (CR) calculations from weight loss data was performed according to the following equation: CR= )(*)( )( 2 hrTimemArea gweightloss (1) The surface coverage ( ) and inhibition efficiency, I% were calculated from the weight loss measurements using the following equations, respectively free inh CR CR )( )( 1 (2) 100 )( )( 1%           free inh CR CR I (3) Where (CR)free, (CR)inh, are the corrosion rate (g/m 2 .hr) in the absence and HCl in absence and presence of peach juice as inhibitor of different concentrations at different temperatures. Table 1, effect of temperature on the corrosion rate (g/m 2 hr) of carbon steel in 1N HCl acid in absence and presence of peach juice as corrosion inhibiton C Si Mn Cr Cu Ti V 0.15 0.164 0.58 0.009 0.0468 0.0089 0.0076 Ni Al Co Fe Mo Pb 0.00352 0.0514 0.0091 98.9 0.005 0.05 Inhibitor conc. cm 3 /l Temperature (°C) 30 40 50 60 Nile C.R  I% 5.14 - - 9.53 - - 38.36 - - 61 - - 5 C.R  I% 2.13 0.585 58.5 3.472 0.636 63.6 11.37 0.7 70 23.04 0.621 62.1 10 C.R  I% 2.08 0.594 59.4 2.73 0.7135 71.35 10.43 0.728 72.8 17.07 0.72 72 20 C.R  I% 2.05 0.6 60 2.223 0.766 76.6 9.722 0.75 75 16.47 0.73 73 30 C.R  I% 1.22 0.763 76.3 2.08 0.7814 78.14 6.8 0.8227 82.27 14.14 0.76 76 40 C.R  I% 1.203 0.766 76.6 1.57 0.835 83.5 5.21 0.86 86 12.59 0.81 81 50 C.R  I% 1.147 0.776 77.6 1.3342 0.869 86.9 4.573 0.88 88 10.98 0.82 82 Aprael S. Yaro and Hadeel F. Ibraheem IJCPE Vol.11 No.1 (March 2010) 67 The corrosion rates of low carbon steel corrosion in absence of inhibitor in 1N HCl acid increased from (5.14 to 61) g/m 2 .h as the temperature increased from 30 to 60 o C .Figure 1,shows the variation of corrosion rate with temperature. The corrosion rate in 1N HCl increases sharply with increasing temperature. Addition of peach juice as inhibitor reduce corrosion rate generally. Table 1, shows the variation in corrosion rate with the inhibitor concentration at various temperature levels. It is clear that the corrosion rate decreases with increasing the concentration of inhibitor at any used temperature, the effect of Temperature on corrosion rate for different concentrations of inhibitor is expressed in Figure 1, .This Figure shows that the corrosion rate increases with increasing temperature at all studied inhibitor concentration. 0 10 20 30 40 50 60 70 20 30 40 50 60 70 Temperatuer ( C) C .R (g /m ^ 2 .h r ) nile 5 10 20 30 40 50 Fig. 1 Effect of Temperature on Corrosion Rate of Low Carbon Steel in 1N HCl at Different Concentrations of inhibitor. Values of inhibition efficiency increase with increasing inhibitor concentration. Figure 2, shows the variation of inhibition efficiency with inhibitor concentration. It varies as follows; from 58.5 to 62 % at 5cm 3 /L inhibitor concentration,from 59.4 to 72% at 10 cm 3 /L,from 60 to 73 % at 20 cm 3 /L,from 76.3 to 76% at 30 cm 3 /L ,from 76.6 to 81% at 40 cm 3 /L and from 77.6 to 82% at 50 cm 3 /L as the temperature increased from 30 up to 60 ºc. 0 20 40 60 80 100 0 5 10 15 20 25 30 35 40 45 50 55 60 65 Inhibitor concentration(cm^3/L) In h ib it io n E ff ic ie n c y (I % ) 30c 40c 50c 60c Fig. 2 Variation of Inhibition Efficiency with Inhibitor Concentration at Different Temperature. 50 55 60 65 70 75 80 85 90 25 30 35 40 45 50 55 60 65 70 75 Temperature C In h ib it io n E f f ic ie n c y ( I% ) 5 1 2 3 4 5 Fig.3 Effect of Temperature on Inhibition Efficiency at Different Inhibitor Concentration. Figure 3, shows the effect of temperature on inhibition efficiency .Inhibition efficiency increase with increasing temperature up to 50ºc then the efficiency reaches a maximum value of 88% at 50 ºC for 50 cm 3 /L . This increase in inhibition efficiency with temperature is presumably due to an increase in adsorption of the inhibitor. Above 50 ºC i.e at 60 ºC) the Values of efficiency decreases. This may be explained due to the structure degradation of existing organic compounds in the inhibitor[8]. The plot of (I %) vs. inhibitor concentration (cm 3 /L) of peach juice as corrosion inhibitor is found to generally increase with inhibitor concentration and approaches 88% in 1NHCl acid at 50 ºc with 50 cm 3 /L of the inhibitor. While the lowest inhibition efficiency is 58.5% at 30ºc and 5 cm 3 /L inhibitor concentration it is shown in Fig 2. The Inhibition Effect of Peach Juice on Corrosion of Low Carbon Steel in Hydrochloric Acid at Different Temperatures 68 IJCPE Vol.11 No.1 (March 2010) The corrosion rate data can be used to analyze the adsorption mechanism.The Langmuir isotherm was expressed as KC KC   1  (4) Where K is the equilibrium constant for the adsorption isotherm representing the degree of adsorption (i.e,the higher the value of K indicates that the inhibitor is strongly adsorbed on the metal surface. C is inhibitor concentration (cm 3 /L) and  is the surface coverage. Rearranging equation will give:- C K C  1  (5) Figure 4, shows plots of C/ vs. C for peach juice as corrosion inhibitor in 1NHCl acid at 30, 40, 50 and 60 ºc. The data fit straight lines indicating that peach juice is adsorbed according to the Langmuir adsorption isotherm from the intercept of straight line on the C/ axis; K values are to be calculated as given in Table 2. Table 4 Equilibrium Constant for Langmuir Type Adsorption of the inhibitor in 1N HCl acid solution at Different Temperatures The rectilinear natures of figure 4 indicate an increase in adsorption with an increase in concentration of and that adsorption occurs in accordance with Langmuir adsorption equation. It is also noted in fig.4, that the lines accumulated and approximately looked like one line, this is due to the very close range of inhibition efficiency (58.5 – 88%). 0 10 20 30 40 50 60 70 0 10 20 30 40 50 60 Inhibitor concentration(Cm^3/L) in h ib it o r c o n c e n tr a ti o n /S u r fa c e C o v e r a g e 30 C 40 C 50 C 60 C Fig. 4 Langmuir adsorption isotherm of peach juice on Low Carbon Steel in 1N HCl at Different Temperature Effect of Temperature Activation energies of low carbon steel in 1N HCl in presence and absence of peach juice are calculated from Arrhenius plots fig 5. It is observed that in uninhibited 1N HCl acid solution,the activation energy of the dissolution process is 16 kcal/mol (67.2 kJ/mol). The relationship between the corrosion rate (C.R) of carbon steel in acidic media and temperature (T) is often expressed by: RT Ea ACR 303.2 loglog  (6) Where, Ea is the apparent effective activation energy, R the general gas constant and A the Arrhenius pre- exponential factor. A plot of Log of corrosion rate obtained by weight loss measurement vs.1/T gave straight lines as shown in figure 4.5. The values of activation energy (Ea) obtained from the slop of the lines are given in Table 3.The Activation energies in presence of inhibitor are lower than uninhibited acid i.e. 16 kcal/mol (67.2 kJ/mol) since only small differences are observed between the values of activation energy calculated .At different concentration, the activation energy is considered to be essentially, constant (mean) value of 15.3 kcal/mol (63.58 kJ/mol) for peach juice independent of it's concentration.. Some authors have reported values of Ea < 80 kJ/mol as an indicator of physical adsorption, While value of Ea > 80 kJ/mol are related to chemical adsorption so the lower Ea in inhibited solutions compared to the uninhibited indicated of physical adsorption mechanism[9]. 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.95 3 3.05 3.1 3.15 3.2 3.25 3.3 3.35 (1/T)*1000K^-1 L o g (C .R ) 5 10 20 30 40 nil 50 Fig. 5 Arrhenius plot for log corrosion rates (g/m 2 h) versus reciprocal of absolute temperature at different inhibitor concentration. Some other activation parameters such as the enthalpy change of activation (∆H) and entropy change of activation (∆S) were obtained from the Eyring transition state equation which is an alternative formula for the Arrenius equation[10]:- Temperature( o C) K Value (cm 3 /l) -1 Slope 30 0.175 1.14 40 0.306 1.11 50 0.334 1.09 60 0.357 1.1 Aprael S. Yaro and Hadeel F. Ibraheem IJCPE Vol.11 No.1 (March 2010) 69 )exp()exp( RT H R S Nh RT Rate   (7) Where, h is the Plank's constant,(i.e., h = 6.626  10 -34 Joule.sec) N the Avogadro number,( N = 6.023  10 23 molecules g-mole -1 ) A plot of Log ( Rate/T) vs. 1/T should give a straight line, Figure6,with a slop of (-∆H / 2.303 R)and an intercept of [(Log (R/Nh) + (∆S/ 2.303 R)],from which the values of ∆S and ∆H were calculated .These are listed in Table 3,The values of activation parameter (∆H) in presence of inhibitor are less than that in the absence of inhibitor(nil) . these exhibit high inhibition efficiency at elevated temperature. The positive values of (∆H) both in absence and presence of inhibitor reflect the endothermic nature of the steel dissolution process and means that the dissolution of steel is difficult. It is also clear that the activation enthalpies vary in the same manner as the activation energies, supporting the proposed inhibition mechanism. The values of activation ∆S in the absence and presence of inhibitor are large and negative. This indicates that the activated complex in the rate determining step represents an association rather than a dissociation step, meaning that a decrease in disordering takes place on going from reactants to the activated complex. It is obviously that the ∆S shifts to more negative values (more ordered behavior) with increasing inhibition efficiency, this can be explained that the inhibitor species may involved in the activated complex of the corrosion reaction leading to more ordered system [10]. -3 -2.5 -2 -1.5 -1 -0.5 0 2.95 3 3.05 3.1 3.15 3.2 3.25 3.3 3.35 (1/T)*1000K^-1 L O G (C R /T ) nile 5 10 20 30 40 50 Fig. 6, Adsorption isotherm plot for Log (C.R) of Low carbon steel Versus Reciprocal of Absolute Temperature in the presence and absence of Peach Juice Table 3, thermodynamic activation parameters for carbon steel in 1N HCl in the absence and presence of inhibitor concentrations Polarization Technique A total of 28 runs were made,4 runs for uninhibited acid solution and the remaining inhibited acid solution at six levels of inhibitor concentrations and four levels of temperature variation by BETA CRUNCH method[12] and the same runs by Tafel Extrapolation method.The electrode potentials are expressed relative to the saturated Calomel Electrode (SCE). The corrosion potentials obtained from polarization measurements were observed to be influenced by the variables studied. Tables 4, results of the corrosion potential of low carbon steel. It can be seen that: 1. the corrosion potential shifts to more positive direction as the inhibitor concentration increases, This shifting explain the anodic nature of inhibitor, which inhibits the anodic reaction more than the cathodic one 2. The values of Ecorr also show that the corrosion potential shifts to more negative direction with temperature Table 4, Corrosion Potential, (mV) vs. SCE at Different Temperature and Inhibitor concentration Inhibitor concentration (Cm 3 /L) (∆H) kJ/mol (-∆S) J/mol Ea kJ/mol Nil 70.43 125.2 67.2 5 66.56 145.8 64.134 10 61.1 164.33 60.186 20 61.06 165.18 61.61 30 68.98 142.4 66.36 40 65.29 155.6 64.26 50 63.25 163.02 61.32 Inh.Conc. (cm 3 /l) Temperature (º C) 30 40 50 60 Nil -480 -496 -505 -513 5 -472 -486 -488 -496 10 -468 -481 -485 -489 20 -463 -475 -481 -487 30 -459 -472 -470 -482 40 -454 -470 -469 -479 50 -450 -465 -466 -476 The Inhibition Effect of Peach Juice on Corrosion of Low Carbon Steel in Hydrochloric Acid at Different Temperatures 70 IJCPE Vol.11 No.1 (March 2010) Figures 11 through 17 show the polarization curves in absence and presence of the inhibitor at different temperatures. It is clear from these figures that: The increase in temperature shifts the anodic and cathodic curves in the direction of higher current density, Table (5 through 8) for Beta Crunch method and Table.9 through 12 for Tafel Extrapolation method, show that with increasing in temperature in absence and presence of the inhibitor at different concentration. The Corrosion Rate (Corrosion Current Density) increases, this means that with increasing temperature the efficiency of inhibitor decrease. The same behavior was observed in weight loss technique.Figures 7 through 10, show the polarization curves for each temperature 30 ,40 , 50 and 60º C at different inhibitor concentration. It is clear from these figures that The increase in inhibitor concentration shifts the anodic and cathodic curves in the direction of loss current density at all temperature studied, indicate that the peach juice have effect on both anodic and cathodic reaction of corrosion process. Computation Polarization Resistance (Rp) The Polarization Resistance defined as slop of Potential - current density (∆E/∆I), curve at free corrosion potential (± 20mv) yield the polarization resistance Rp[11] it is shown in Fig 18 through 21. 0          E p I E R (8) The corresponding corrosion current density depends on kinetic parameters since Icorr = f ( , Rp) .Thus, the simple linear relation that defines the corrosion current density is of the form pR icorr   (9) Where  = f (a, c) a , c are taken as positive kinetic parameters for determining icorr of a corroding or oxidizing metallic material.This method requires knowledge of the Tafel anodic and cathodic slopes in order to calculate  ) (303.2 . ca ca      (10) The Tafel parameters can be determined by mean of experimental measurements carried out over a rang of potential shifting away from the corrosion potential.In the Tafel extrapolation methode (± 50 mv) for the corrosion potential,but by the Beta Crunch method [73] Tafel parameters will be calculated with in a bout (± 20 mv) for the corrosion potential. -900 -800 -700 -600 -500 -400 -300 -200 -100 -6.5 -5.5 -4.5 -3.5 -2.5 -1.5 -0.5 Log(I)(A/cm^2) E (m v ) nile 5 10 20 30 40 50 Fig 7,Polarization Curves of Low Carbon Steel in 1N HCl and containing Different Inhibitor Concentration at 30 o C -1000 -900 -800 -700 -600 -500 -400 -300 -200 -100 -5.5 -4.5 -3.5 -2.5 -1.5 -0.5 Log(I)(A/cm^2) E (m v ) 5 10 nil 20 30 40 50 Fig 8 Polarization Curves of Low Carbon Steel in 1N HCl and containing Different Inhibitor Concentration at 40 o C. Aprael S. Yaro and Hadeel F. Ibraheem IJCPE Vol.11 No.1 (March 2010) 71 -1000 -900 -800 -700 -600 -500 -400 -300 -200 -100 0 -5.4 -4.4 -3.4 -2.4 -1.4 -0.4 0.6 Log(A/cm^2) E (m v ) 30 c 40 c 50 c 60c -1000 -900 -800 -700 -600 -500 -400 -300 -200 -100 -5.5 -4.5 -3.5 -2.5 -1.5 -0.5 Log(I)(A/cm^2) E (m v ) nile 5 10 20 30 40 50 Fig 9 Polarization Curves of Low Carbon Steel in 1N HCl and containing Different Inhibitor Concentration at 50 o C. -900 -800 -700 -600 -500 -400 -300 -200 -100 -5.5 -4.5 -3.5 -2.5 -1.5 -0.5 Log(I)(A/cm^2) E (m v ) nile 5 10 20 30 40 50 Fig 10 Polarization Curves of Low Carbon Steel in 1N HCl and containing Different Inhibitor Concentration at 60 o C. -900 -800 -700 -600 -500 -400 -300 -200 -100 0 -5 -4 -3 -2 -1 0 1 Log(A/cm^2) E (m v ) 30c 40c 50c 60c Fig 11, Polarization Curves of Low Carbon Steel in1N HCl in absence of peach Juice at Different Temperatures. Fig 12, Polarization Curves of Low Carbon Steel in1N HCl with (5cm3/l)) of peach Juice at Different Temperatures. -1000 -900 -800 -700 -600 -500 -400 -300 -200 -100 0 -5.4 -4.4 -3.4 -2.4 -1.4 -0.4 0.6 Log(A/cm^2) E (m v ) 30 c 40 c 50 c 60 c Fig 13, Polarization Curves of Low Carbon Steel in1N HCl with (10cm3 /l)of peach Juice at Different Temperatures. -1000 -900 -800 -700 -600 -500 -400 -300 -200 -100 -5.3 -4.3 -3.3 -2.3 -1.3 -0.3 0.7 Log(A/cm^2) E (m v ) 30 C 40 C 50 C 60 C Fig 14, Polarization Curves of Low Carbon Steel in1N HCl with (20cm3/l)) of peach Juice at Different Temperatures.. The Inhibition Effect of Peach Juice on Corrosion of Low Carbon Steel in Hydrochloric Acid at Different Temperatures 72 IJCPE Vol.11 No.1 (March 2010) -1000 -900 -800 -700 -600 -500 -400 -300 -200 -100 -5.2 -4.2 -3.2 -2.2 -1.2 -0.2 0.8 Log(A/cm^2) E (m v ) 30 C 40 C 50 C 60 C Fig 15, Polarization Curves of Low Carbon Steel in1N HCl with (30cm3/l)of peach Juice at Different Temperatures. -900 -800 -700 -600 -500 -400 -300 -200 -100 -5.8 -4.8 -3.8 -2.8 -1.8 -0.8 0.2 Log(A/cm^2) E ( m v ) 30 C 40 C 50 C 60 C Fig 16, Polarization Curves of Low Carbon Steel in1N HCl with (40cm3/l)) of peach Juice at Different Temperatures. -1000 -900 -800 -700 -600 -500 -400 -300 -200 -100 0 -5.8 -4.8 -3.8 -2.8 -1.8 -0.8 0.2 Log(A/cm^2) E (m v ) 30 C 40 C 50 C 60 C Fig 17, Polarization Curves of Low Carbon Steel in1N HCl with (50cm3/l) of peach Juice at Different Temperatures. -20 -15 -10 -5 0 5 10 15 -0.15 -0.1 -0.05 0 0.05 0.1 0.15 I(mA/cm^2) P o la r iz a ti o n (E -E c o r r )m v Fig 18, Schematic linear Polarization Curve of Low Carbon Steel in1N HCl in absence of peach Juice at (30ºC). -20 -15 -10 -5 0 5 10 15 20 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4 I(mA/cm^2) P o la r iz a ti o n (E -E c o r r )m v Fig 19, Schematic linear Polarization Curve of Low Carbon Steel in1N HCl in absence of peach Juice at (40ºC) . -30 -20 -10 0 10 20 30 -0.4 -0.2 0 0.2 0.4 I(mA/cm^2) p o l a r i z a t i o n ( E - E c o r r ) m v Fig.20, Schematic linear Polarization Curve of Low Carbon Steel in1N HCl in absence of peach Juice at (50ºC) . Aprael S. Yaro and Hadeel F. Ibraheem IJCPE Vol.11 No.1 (March 2010) 73 -30 -20 -10 0 10 20 30 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 I(mA/cm^2) P o l a r i z a t i o n ( E - E c o r r ) m v Fig 21, Schematic linear Polarization Curve of Low Carbon Steel in1N HCl in absence of peach Juice at (60ºC) . Table 5, Data of Beta Crunch for Polarization Measurements of Low Carbon Steel in 1N HCl in Absence and Presence of Different Concentration of peach Juice at T= (30º C) Inh. Conc.(cm 3 /L) Rp (Ω.cm 2 ) a (mv/dec) c (mv/dec) Icorr (A/cm 2 ) Eff (I%) Nil 153.5 33.244 -56.46 5.9*10 -5 - 5 338.1 32.54 -55.8 2.64*10 -5 54 10 395.8 36.65 -54.3 2.4*10 -5 60 20 493.8 39.3 -54 2*10 -5 68 30 608.9 37.135 -56.7 1.6*10 -5 74 40 683.6 35.2 -51.8 1.33*10 -5 77 50 750.5 33.7 -55.2 1.21*10 -5 78 Table 6, Data of Beta Crunch for Polarization Measurements of Low Carbon Steel in 1N HCl in Absence and Presence of Different Concentration of peach Juice at T= (40º C) Inh. Conc.(cm 3 /L) Rp (Ω.cm 2 ) a (mv/dec) c (mv/dec) Icorr (A/cm 2 ) Eff (I%) Nil 115.16 35.67 -57.66 8.3*10 -5 - 5 293.4 40.69 -63.49 3.6*10 -5 60 10 382.2 42.8 -55.227 2.7*10 -5 70 20 435.3 38.529 -58.63 2.3*10 -5 73 30 576.5 40.93 -59.74 1.8*10 -5 79 40 664.3 38.89 -55.39 1.49*10 -5 82 50 665 33.225 -48.36 1.288*10 -5 83 The Inhibition Effect of Peach Juice on Corrosion of Low Carbon Steel in Hydrochloric Acid at Different Temperatures 74 IJCPE Vol.11 No.1 (March 2010) Table 7, Data of Beta Crunch for Polarization Measurements of Low Carbon Steel in 1N HCl in Absence and Presence of Different Concentration of peach Juice at T= (50º C) Inh. Conc.(cm 3 /L) Rp (Ω.cm 2 ) a (mv/dec) c (mv/dec) Icorr (A/cm 2 ) Eff (I%) Nil 92.3 44.278 -76.42 1.32*10 -4 - 5 264 38.363 -61.478 3.8*10 -5 65 10 316.3 41.351 -64.968 3.46*10 -5 71 20 425.25 45.34 -60.133 2.6*10 -5 78 30 507.8 44.27 -63.361 2.2*10 -5 82 40 568 40.497 -59.84 1.8*10 -5 84 50 695 35.93 -54.35 1.35*10 -5 88 Table 8, Data of Beta Crunch for Polarization Measurements of Low Carbon Steel in 1N HCl in Absence and Presence of Different Concentration of peach Juice at T= (60º C) Inh. Conc.(cm 3 /L) Rp (Ω.cm 2 ) a (mv/dec) c (mv/dec) Icorr (A/cm 2 ) Eff (I%) Nil 73.2 51.35 -68.23 1.73*10 -4 - 5 146.4 47.76 -72.81 8.68*10 -5 50 10 161.35 46.57 -70.08 7.5*10 -5 55 20 183.5 47.56 -72.42 6.8*10 -5 60 30 198.1 44.133 -69.63 5.9*10 -5 64 40 224.7 49.166 -72.3 5.17*10 -5 68 50 265.7 47.42 -68.588 4.6*10 -5 73 Table 9, Data of Tafel extrapolation for Polarization Measurements of Low Carbon Steel in 1N HCl in Absence and Presence of Different Concentration of peach Juice at T= (30º C). Inh. Conc.(cm 3 /L) Rp (Ω.cm 2 ) a (mv/dec) c (mv/dec) Icorr (A/cm 2 ) Eff (I%) Nil 153.5 80.64 -103.98 1.3*10 -4 - 5 338.1 56.87 -124.16 5.11*10 -5 60.6 10 395.8 62.3 -127.195 4.74*10 -5 63.5 20 493.8 57.93 -125.044 3.52*10 -5 72.9 30 608.9 57.48 -89.27 2.52*10 -5 80.6 40 683.6 63.09 -108.02 2.5*10 -5 80.7 50 750.5 64.174 -133.68 2.49*10 -5 80.9 Table 10, Data of Tafel extrapolation for Polarization Measurements of Low Carbon Steel in 1N HCl in Absence and Presence of Different Concentration of peach Juice at T= (40º C). Inh. Conc.(cm 3 /L) Rp (Ω.cm 2 ) a (mv/dec) c (mv/dec) Icorr (A/cm 2 ) Eff (I%) Nil 115.16 105.38 -109.59 1.93*10 -4 - 5 293.4 134.9 -166.83 1.13*10 -4 40 10 382.2 64.64 -128.7 5.09*10 -5 73 20 435.3 58.94 -156.02 4.31*10 -5 77 30 576.5 55.121 -131.9 2.9*10 -5 84 40 664.3 116.12 -94.43 3.4*10 -5 82 50 665 61.81 -114.98 2.63*10 -5 86 Aprael S. Yaro and Hadeel F. Ibraheem IJCPE Vol.11 No.1 (March 2010) 75 Table 11, Data of Tafel extrapolation for Polarization Measurements of Low Carbon Steel in 1N HCl in Absence and Presence of Different Concentration of peach Juice at T= (50º C). Inh. Conc.(cm 3 /L) Rp (Ω.cm 2 ) a (mv/dec) c (mv/dec) Icorr (A/cm 2 ) Eff (I%) Nil 92.3 87.97 -126.5 2.62*10 -4 - 5 264 60.85 -132.88 6.78*10 -5 74 10 316.3 77.433 -120.45 6.69*10 -5 74 20 425.25 98.5 -109.87 5.24*10 -5 80 30 507.8 61.59 -116.9 3.52*10 -5 86 40 568 77.93 -91.6 3.33*10 -5 87 50 695 49.44 -113.4 2.2*10 -5 91 Table 4.12, Data of Tafel extrapolation for Polarization Measurements of Low Carbon Steel in 1N HCl in Absence and Presence of Different Concentration of peach Juice at T= (60º C). Inh. Conc.(cm 3 /L) Rp (Ω.cm 2 ) a (mv/dec) c (mv/dec) Icorr (A/cm 2 ) Eff (I%) Nil 73.2 79.47 -138.24 3.22*10 -4 - 5 146.4 79.23 -87.7 1.29*10 -4 60 10 161.35 48.9 -123 9.5*10 -5 70 20 183.5 73.25 -125.01 1.04*10 -4 67 30 198.1 70.53 -118.13 9.33*10 -5 71 40 224.7 57.19 -158.24 8.3*10 -5 74 50 265.7 56.7 -131.3 6.76*10 -5 79 Conclusions 1. It was found that the activation energy in absence of inhibitor was 16 kcal/mol (67.2 kJ/mol) .This value decreased down to a constant mean 15.3 kcal/mol. This mean that the activation energy of the reaction is inhibitor concentration independent. 2. Inhibition efficiency increase with increasing temperature to 50ºC and then decreasing with temperature while this efficiency increased with increas inhibitor concentration. 3. The positive value of ∆H both in absence and presence of inhibitor reflect the endothermic nature of the steel dissolution process. The values of ∆S are large and negative meaning that decrease in disordering takes place on going from reactants to the activated complex. 4. It was found that the corrosion current density increase with increasing temperature and decrease with increasing inhibitor concentration. 5. The resistance polarization decrease with increasing temperature and increase with increasing inhibitor concentration. 6. This investigation shows that Peach Juice is an effective friendly inhibitor, Max. Efficiency obtained was a bout 91%. 7. Peach Juice was found to effect both anodic and cathodic reaction as mixed effect inhibitor, but more is anodic inhibitor. References 1. H.Ashassi-Sorkhabi,M.R.Majidi and K.Seyyedi, Applied Surface Science,225(2004)176. 2. A.Y. El-Etre, Corrosion Science,40 (1998)1845. 3. H. Ashassi-Sorkhabi, Z. Ghasemi and D. Seifzadeh, Applied Surface Science,249 (2005)408. 4. K. C. Emregül and M. Hayvalı, Materials Chemistry and Physics,83(2004)209. 5. S.A. Abd El-Maksoud, Electrochimica Acta,49(2004) 4205. The Inhibition Effect of Peach Juice on Corrosion of Low Carbon Steel in Hydrochloric Acid at Different Temperatures 76 IJCPE Vol.11 No.1 (March 2010) 6. G.I Gardner. Corrosion inhibitor, C.C. Nathan Ed., NACE, 156. 7. S.S. Abd El Rehim, M.A.M. Ibrahim and K.F. Khalid. The Inhibition of 4-(2'-amino-5'- Methylphenylazo) antipyrine on corrosion of mild steel in HCl solution. Material Chemistry and Physics,70(2001)268. 8. Ashassi-sorkhabi H.,D.seifzadeh "The inhibition of steel corrosion in hydrochloric acid solution " International Journal of electrochemical science May(2006)(www. electrochemsci.org). 9. Olivares.O,Likhanova N.V,"Electrochemical and XPS studies of decylamides of α-amino acids adsorption on carbon steel in acidic environment" Journal of Applied Surface science 252(2006) 2894- 2909 www.Elsevier.com/locate/apsusc. 10. KHAN.S.,Quraishim A. "Inhibition of mild steel corrosion in sulfuric acid solution by thiadiazoles" Journal of Applied Electrochemistry 36,539-544. (2006). 11. George, G., “Corrosion Inhibitors”; (NACE), Houston Texas (1974). 12. N.Green, &R.Gandi, Material Performance, July, (1982). 13. S.D. Casini and R. Bagger-Jorgensen, Cross Flow Filtration of Fruit Juice, (www.mst.dk/udgiv/Publications/2000/87-7944-134- 3/html/kap02_eng.htm). 14. E.S. Ferreira, C. Giacomelli, F.C. Giacomelli, A. Spinelli; Materials Chemistry and Physics,83(2004)129. 15. E. Rocca, C. Rapin and F. Mirambet, Corrosion Science,46(2004)653 16. K. Tebbji, H. Oudda, B. Hammouti, M. Benkaddour, M. El Kodadi and A. Ramdani, Colloids and Surfaces A: Physicochem. Eng. Aspects259(2005)143 http://www.elsevier.com/ http://www.mst.dk/udgiv/Publications/2000/87-7944-134-3/html/kap02_eng.htm http://www.mst.dk/udgiv/Publications/2000/87-7944-134-3/html/kap02_eng.htm