Anees A. Khadom

Peach juice as an anti‐corrosion inhibitor of mild steel

Purpose – The aim of this paper is to investigate peach juice as a cheap, raw, green and non‐toxic anti‐corrosion material for mild steel corrosion in hydrochloric acid at different temperatures.Design/methodology/approach – The corrosion inhibition of mild steel in 1 M HCl solution in the presence of peach juice at temperature range of 30‐60°C and concentration range of 5‐50 cm3/l was studied using weight loss and polarization techniques. The inhibition effect, adsorption characteristics, mathematical and electrochemical modeling of peach juice were addressed.Findings – Results show that inhibition efficiency rose with the increase of inhibitor concentration and temperature up to 50°C, while at temperatures above 50°C the values of efficiency decreased. The inhibitor adsorbed physically on metal surface and followed the Langmuir adsorption isotherm. Monolayer formed spontaneously on the metal surface. Maximum inhibition efficiency obtained was about 91 percent at 50°C in the 50 cm3/l inhibitor concentrat...

ADSORPTION MECHANISM OF BENZOTRIAZOLE FOR CORROSION INHIBITION OF COPPER-NICKEL ALLOY IN HYDROCHLORIC ACID

ABSTRACT The inhibition of copper corrosion by Benzotriazole (BTA) in 5% HCl has been investigated by weight loss technique at different temperatures. Langmuir adsorption isotherm, Freundlich Adsorption Isotherm and Kinetic-Thermodynamic Model were used to describe the adsorption process depending on values of surface converge. Maximum value of surface converge was 0.998 for BTA at 35 o C and 15 g/l inhibitor concentration, while the lower value was 0.868 at 55 C and 1 g/l inhibitor concentration. The films formed on the copper-nickel alloy surface of BTA appeared to obey the Langmuir Adsorption Isotherm more than Freundlich adsorption isotherm. In the other hand, results showed that the Kinetic-Thermodynamic Model was unsuitable to fit the experimental data of the BTA of the present study. Keywords: adsorption isotherms, corrosion inhibition, copper-nickel alloy, benzotriazole, inhibitor efficiency INTRODUCTION Copper and its alloys are commonly employed as a material in heating and cooling systems due to their good thermal conductivity and mechanical properties. Hydrochloric acid pickling is extensively used for the removal of rust and scale on heat transfer in several industrial processes. However, these systems should be regularly cleaned from carbonates and oxides that diminish their heating transmission. Diluted hydrochloric acid is used to clean these surfaces; a corrosion inhibitor is added to avoid the action of this acid on copper. Corrosion inhibitor is a chemical substance when it is added with little concentration to environment effectively checks, decreases or prevents the reaction of metal with environment

Modeling of corrosion inhibition of copper-nickel alloy in hydrochloric acid by benzotriazole

The corrosion inhibition of copper-nickel alloy by benzotriazole (BTA) in 1.5 M HCl has been investigated by weight loss and polarization techniques at different temperatures. Maximum value of inhibitor efficiency was 99.8% at 35°C and 0.1 M inhibitor concentration, while the lower value was 86.3% at 65°C and 0.02 M inhibitor concentration. The activation energy values were higher in presence of BTA which indicate that in presence of inhibitor, corrosion reaction requires more energy to occur. Two mathematical models were used to represent the weight loss corrosion rate data with high correlation coefficients. Electrochemical polarization measurements showed that BTA is a mixed type inhibitor.

Protection of low carbon steel in phosphoric acid by potassium iodide

The corrosion of low carbon steel in 2.5 M phosphoric acid at temperature range of 30–60°C in presence and absence of potassium iodide as an inorganic inhibitor in the range of 0.02–0.05 M at static condition has been investigated. Weight loss and polarization techniques were employed in this investigation. The maximum value of inhibitor efficiency obtained was 99.95% at 50°C in presence of 0.05 M inhibitor concentration. The fraction of surface covered calculated from corrosion rates followed the Langmuir adsorption isotherm. Polarization experiments showed that for a given temperature, the curves were shifted towards the potential axis leading to lower the corrosion rates as the inhibitor concentration increased. Potassium iodide inhibits carbon steel corrosion in H3PO4 acid by affecting both anodic and cathodic partial reactions with the anodic reaction being more prevailing.

The role of 4-amino-5-phenyl-4H-1,2,4-triazole-3-thiol in the inhibition of nickel–aluminum bronze alloy corrosion: electrochemical and DFT studies

Inhibition of corrosion of nickel–aluminum bronze alloy (NAB) by use of 4-amino-5-phenyl-4H-1,2,4-triazole-3-thiol (APTT) was investigated by monitoring weight loss and open-circuit potentials (OCP), and by use of electrochemical impedance spectroscopy (EIS). Quantum chemical data were calculated by use of the density functional theory (DFT) model. Results showed that APTT inhibits corrosion of NAB alloy fairly well. The efficiency of inhibition increases with increasing concentration of APTT, and adsorption of the inhibitor obeys the Langmuir adsorption isotherm model. Negative values of adsorption free energy indicate chemical adsorption is spontaneous. The theoretical study showed that sulfur and nitrogen atoms (S, N7 and N8) were the reactive sites.

Kinetic and mathematical approaches to the corrosion of mild steel in nitric acid

The effect of different temperatures and acid concentrations on the corrosion of mild steel in nitric acid are addressed in this work. The effect of temperature is explained by the application of the Arrhenius equation and transition state theory, while the acid concentration effect is explained using reaction kinetic equations. The combined effect of temperature and acid concentration is then modeled using a nonlinear regression method. Thermodynamic parameters of activation (E, ΔH* and ΔS*) and detailed kinetic studies for the corrosion reaction are carried out. Nonlinear corrosion rates as a function of temperature and acid concentration are estimated with a good prediction of corrosion rate values. The values of activation energy E and enthalpy of activation ΔH* decrease with an increase in acid concentration indicating the increasing reaction rate. Entropies of activation ΔS* tend to lower values with increasing acid concentration, which indicates that the activated complex is more orderly relative to the initial state. The corrosion reaction was approximately first order.

Polarisation resistance behaviour of corrosion inhibition of low carbon steel in H3PO4 acid

The non-linear region of polarisation curve near the corrosion potential can be discussed depending on data of over potential as a function of current densities. These data can be analysed by suggesting a mathematical model taking into account the effect of mass transfer on activation process. This model was used to evaluate the values of polarisation resistance Rp in presence and absence of potassium iodide (KI) as a corrosion inhibitor of low carbon steel in 2.5 M phosphoric acid at different temperatures. The values of polarisation resistance obtained by mathematical model compared with these obtained by Tafel parameters. The suggested s-model was very useful in evaluating the values of Rp. The maximum value of polarisation resistance was 5049.13 Ωcm² at 30°C in presence of 0.05 M KI, while the minimum value was 1.885 Ωcm² at 60°C in absence of KI. These results indicate that the polarisation resistance values increased with the increase of KI concentration, and decreased with the increase of temperature.

Study for prevention of steel corrosion by sacrificial anode cathodic protection

Corrosion of steel tube in sea water was controlled by cathodic protection. Sacrificial anode technique was used. In this technique, weight loss method was used to determine the rate of zinc consumption as a function of temperature, time, pH and solution velocity. Reaction kinetics studies showed that the rate of zinc consumption was first order. Activation parameters were obtained from Arrhenius equation and transition state equation. Two mathematical models were suggested to represent the consumption data. Statistical analysis proved that the second-order multi-terms model was better than the one-term model.

Modeling of corrosion reaction data in inhibited acid environment using regressions and artificial neural networks

This paper reports the results of mass loss measurements in the corrosion inhibition of mild steel in different concentrations of H3PO4 in the temperature range 30–60 °C using potassium iodide as an inhibitor. The present work is focused on determining the optimum mathematical equation and the ANN architecture in order to gain good prediction properties. Three mathematical equations and three ANN architectures are suggested. Computer aided program was used for developing these models. The results show that the polynomial mathematical equation and multi-layer perception are able to accurately predict the measured data with high correlation coefficients.

Studying the Effect of Some Surfactants on Drag Reduction of Crude Oil Flow

The influence of SDBS, SLS, SLES, and SS as drag reducing agents on flow of Iraqi crude oil in pipelines was investigated in the present work. The effect of additive type, additive concentration, pipe diameter, solution flow rate, and the presence of elbows on the percentage of drag reduction (%Dr) and the amount of flow increases (%FI) was addressed. The maximum drag reduction was 55% obtained at 250 ppm SDBS surfactant flowing in straight pipes of 0.0508 m I.D. The dimensional analysis was used for grouping the significant quantities into dimensionless groups to reduce the number of variables. The results showed good agreement between the observed drag reduction percent values and the predicted ones with high value of the correlation coefficient.