An Innovative Application of NanoTechnology in The Production of Hybrid Inorganic-Organic Coatings of Crude Oil Tanks

Three corroded mediums that found in the crude oil have been applied to carbon steel specimens. The effect of the corrosion mediums concentration, application periods and times investigated. The Gravimetric method showed that sodium thiosulfate has the highest corrosion effect at all corrosion test parameters followed by sodium sulfate and sodium carbonate respectively. Each of Nano zinc oxide, Nano cotton cellulose and Nano banana cellulose protective films inhibit sodium thio sulfate corrosion effect. Anti-corrosion behaviour of the formed Nano films studied using gravimetric method (weight loss method), electrochemical method (potentiodynamic polarization) and scanning electron microscope (SEM) techniques. The nano zinc oxide heated at 700OC shown to have better inhibition efficiency followed by nano zinc oxide heated at 600OC, Nano cotton cellulose and nano banana cellulose respectively. The potentiodynamic polarization measurements showed nano zinc oxide heated at 700OC, Nano cotton cellulose, and nano banana cellulose the acted as mixed-type inhibitors with predominantly cathodic effectiveness. SEM techniques supported the achievement of corrosion inhibition with the presence of inhibitors.

Protective painting systems include a primer and topcoat 17 .Saji 18 deduced that for many years, coatings must have steel structures corrosion protection principal element.Drozdz, Hawkins, Clark, Surratt, Kingsley, Palutke, and Dean 19 detected the polarization technique parameters effect on the oil pipelines corrosion.Galvanized steel with Nano composite has advantages in comparison with both the ZnO and PPy [20][21][22][23] .The oxidation/ corrosion of different metallic substrates improved using organic-inorganic hybrid coatings [24][25] .Al-Naamani, Dobretsov, Dutta, and Burgess 26 used (chitosan-ZnO) nanoparticle hybrid coatings and their antifouling activity tested.Abo-Dief, Morsi, and Mohamed 27 , and Abo-Dief, Al-Ghamdi, Al-Zahrani, and Mohamed 28 showed that addition of Nano Zn in the deposition process increases the corrosion resistance.Abo-Dief 29 used positron annihilation, in detecting Zn, ZnO 2 and Zn-ZSM-5 Nano powders properties.Abualnaja, and Abo-Dief 30 synthesed silver nanoparticles by different types of plants and Vera, Schrebler, Cury, Del Rı´o, Romero 31 evaluated the corrosion protection of carbon steel using synthesed polyaniline and poly(ortho-methoxyaniline) (Poma).Abo-Dief, Emam, Abualnaja, and Mohamed 32 producing the biodiesel from corn waste frying oil and five fresh vegetable oils (corn, rapeseed, sunflower, soybean and palm).Sherif, Saheb, El-Zatahry, kenawyand, and Alkaraki 33 concluded that PVA and PVC coatings decrease the corrosion currents and corrosion rate of carbon steel.Pujari, S; Ramakrishna, A; and Kumar 34 discussed the uses and applications of jute and banana fiber composites.The present work aimed at determining the Poly vinyl alcohol (PVA), Nano Banana and cotton cellulose and Nano zinc oxide coated carbon steel corrosion efficiency against one of three aggressive media; sodium thio sulfate, sodium sulfate and sodium carbonate.The effect of the corrosion test periods, temperature and corrosion media concentrations carried out and investigated.

EXPERIMENTAL Material Preparation
Test specimens prepared by polishing, rinsing with distilled water, degreasing in ethanol, and drying at hot air.Carbon steel specimens corrosion test specimens performed with a rectangular form of 2.0 cm × 1.0 cm × 0.2 cm at an immersion time of; 24 h, 48 h, 72 h and 96 h at 25 O C, 60 O C and 100 O C. After immersion period, the specimens cleaned according and reweighed to 10-4 g for determining the weight loss.Three solutions; sodium thio sulfate, sodium sulfate and sodium carbonate of; 0.01 M, 0.03 M and 0.05 M concentrations used at 100 ml basic oil.

Preparation of Coating Material
Banana fruit and cotton fibers were purchased from local market and prepared as Nano cellulose.The concentration of both Nano materials mixed with water as; 1W cellulose:10W water.Poly vinil Alcohol is purchased and used as a coating medium.Zinc oxide is also purchased from the local market and heat treated at 600 O C and 700 O C and cooled in furnace and used as a corrosion medium.

Gravimetric measurements
After immersion period in the corrosion medium, the specimens cleaned and reweighed using a balance scale to 10-4 g for determining the weight loss.At each case, triplicate specimens used to get the mean value of the weight loss.

Electrochemical measurements
The specimens of the higher corrosion medium subjected to the electrochemical measurements.The overall current density values, I, considered as the sum of two contributions, anodic and cathodic current Ia and Ic, respectively.The corrosion inhibition efficiency evaluated from the corrosion current densities values using the relationship (1): Where I corr and Io corr are the corrosion current densities values with and without inhibitor, respectively 35 .The surface coverage (θ) obtained from polarization curves for various concentrations of inhibitor using the following equation ( 2): Where Icorr, and Io corr are the corrosion current densities values with and without inhibitor, respectively 35 .

Electrochemical Studies
Electrochemical studies carried using advanced corrosion measurement instrument.Three electrodes of carbon steel 1cmX1cmX0.5cmas working electrode connected to anode, platinum as counter electrode connected to cathode and a reference electrode Ag/ AgCl used.

Potentiodynamic Polarization Measurement (TAFEL)
The TAFEL polarization curves obtained by scanning the electrode potential with respect to Ecorr with a scanning rate of 1 mVs -1 .The linear segments of the anodic and cathodic curves extrapolated to obtain the corrosion current densities I corr .Scanning Electron Microscope (Carl Zeiss Supra-55 SEM) used to monitor the surface morphological changes.

Effect of corrosion medium concentration
Figure 1 illustrated the effect of the three corrosion mediums concentrations of 0.01M (a), 0.03M (b) and 0.05M (c) on the carbon steel corrosion at different test periods and 25 O C. The results reveal that the amount of weight loss of carbon steel increases with the corrosion medium concentrations.This is due to the increment of the attacking action of the corrosion medium and the weakling effect of the carbon steel metal.The figure showed that sodium thio sulfate has the highest corrosion effect followed by sodium sulfate and sodium carbonate respectively.Also, the figure showed a corrosion effect of the basic oil due to the corrosion constituents that usually found in the crude oil.There is a weight loss increment related to the sodium carbonate corrosion medium due to the sticking of both the sodium carbonate particles with the loosed carbon steel particles on the carbon steel corroded specimen.

Effect of test period
Figrue 2 illustrated the Variation of test period with the weight loss of the carbon steel specimens at various concentrations at 60 O C. it is clear that as the test period increases, the weight loss increases for all types of the corrosion mediums due to the increment application period of the carbon steel specimen to the attacking corrosion mediums that increases the weakness of the steel with time.As observed in 3.1.1.The sodium thio sulfate corrosion trend is found higher followed by sodium sulfate and sodium carbonate respectively.

Effect of test temperature
Figure 3 showed that as the test temperature increases, the weight loss increases for all types of the corrosion mediums due to the weakening of the carbon steel specimen which facilitate the attacking corrosion mediums.As observed in 3.1.1.The sodium thio sulfate corrosion trend is found higher followed by sodium sulfate and sodium carbonate respectively.

Electrochemical Results
Potentiodynamic polarization curves of carbon steel specimens immersed in the sodium thio sulfate the highest corrosion medium without and with Nano Polyvinyl-Alcohol (FE/PVL) zinc oxide at 600 O C (FE 600ZnO), Nano banana cellulose (FE coat B), Nano cotton cellulose (FE coat C) and Nano zinc oxide at 700 O C (Fe 700 ZnO) coating mediums are given Fig. 4. The current corrosion density (I corr ), corrosion potential (V), inhibition efficiency (E%) and surface coverage values (θ) are given in Fig. 4. Fig. 4a showed that carbon steel coated with Nano ZnO at 700 O C has the lowest current corrosion density followed by carbon steel coated with Nano ZnO at 600 O C, Nano cotton cellulose, Nano banana cellulose, and Polyvinyl-Alcohol respectively with (I corr ) values of; 0.19, 1.79, 5.5, 13.8 and 17.2 mA respectively.So Nano ZnO at 700 O C corrosion inhibitor has the highest corrosion resistance compared to the other corrosion inhibitors used.Also, it is clear that as the temperature increases, the inhibition effect of the coating increases in agreement with [36][37][38] where the Icorr value decrement means the inhibitor concentration increment.The decrease in I corr value indicates that decrease in flow of electrons, i.e., corrosion is supressed on the specimen.Figure 4b showed that carbon steel coated with Nano ZnO at 700 O C has the lowest corrosion potential (V corr ) followed by Nano banana cellulose, Nano cotton cellulose, carbon steel coated with Polyvinyl-Alcohol, and Nano ZnO at 600 O C respectively with (V corr ) values of; 1.01, 1.07, 1.09, 717.0 and 911.0 mV respectively.So, Nano ZnO at 700 O C corrosion inhibitor has the lowest corrosion potential.As the Inhibitor classified as cathodic or anodic according to Vcorr value displacement from the control is greater than 85 mV.If the value is less than 85 mV the inhibitor considered to be mixed type inhibitor.So the Nano ZnO at 700 O C Nano banana cellulose and Nano cotton cellulose inhibitors considered as mixed inhibitor and effective towards cathodic inhibition inagrement with 39 .
Figure 4c showed that carbon steel coated with Nano ZnO at 700 O C has the highest Inhibition efficiency (E%) by carbon steel coated with Nano ZnO at 600 O C, Nano cotton cellulose, Nano banana cellulose and Polyvinyl-Alcohol respectively with (E%) values of; 99.5%, 95%, 84.9%, 62.2% and 52.0%respectively.Comparing the inhibition efficiency of Nano ZnO at 700 O C and Nano ZnO at 600 O C indicated that the inhibition efficiency is temperature-dependent in agreement with 37,39] .Figure 4d showed that carbon steel coated with Nano ZnO at 700 O C has the highest surface coverage (θ) followed by carbon steel coated with Nano ZnO at 600 O C, Nano cotton cellulose, Nano banana cellulose, and Polyvinyl-Alcohol respectively with (θ) values of; 0.995, 0.9, 0.849, 0.622 and 0.52 respectively.Comparing the Inhibition efficiency of Nano ZnO at 700 O C and Nano ZnO at 600 O C indicated that the surface coverage is temperaturedependent in agreement with 36,39 .Since the surface coverage increases with temperature related to the change in the nature of the adsorption mode; the inhibitor is being physically adsorbed at lower temperatures, while Physisorption is favored by increasing of temperature.Thus, at high surface coverage, diffusion through the surface layer containing the inhibitor and corrosion products became the rate-determining step of the metal dissolution process 37 .

Tafel polarization curves
The potentiodynamic polarization measurement allowed for the study of anticorrosion behaviour via anodic and cathodic polarizations.The measurements recorded and analysed as TAFEL plots shown in Fig. 5 with the electrochemical parameters presented in Fig. 4. Fig. 5 illustrated the Tafel curves of Nano coatings.The corrosion potential is indicated by the intersection of the slopes of the cathodic and anodic branches of the curve.Fig. 5a to 5f showed the samples corrosion potential using various coating types.In agreement with the potentiodynamic test variables represented in Fig. 4, the test specimen containing coated with ZnO at 700 O C has the lowest corrosion effect than the other coating mediums.ZnO inhibitor at 700 O C banana and cotton has E corr value displacement less than 85 mV.The result implies that the inhibitor used is mixed inhibitor and effective towards cathodic inhibition.Maximum efficiency found to be 99.95% with ZnO coating at 700 O C.

Surface Examination
Carbon steel surface before subjected to 0.05M sodium thio sulfate shown in  Sodium thio sulfate has the highest corrosion effect followed by sodium sulfate and sodium carbonate respectively.c) The Nano zinc oxide heated at 700 O C shown to have better inhibition efficiency followed by Nano zinc oxide heated at 600 O C, Nano cotton cellulose , Nano banana cellulose and Nano polyvinyl alcohol respectively.d) Potentiodynamic polarization parameters (I corr , V corr , θ. and E %) show that the used inhibitors adsorbed on carbon steel surface.e) Good agreement obser ved between electrochemical curves and scanning electron microscopy images.f) Polarization study reveals that Nano-zinc oxide heated at 700 O C, Nano cellulose cotton, and Nano cellulose banana systems formulation are mixed type of inhibitor.

Fig. 1 .
Fig. 1.Variation of corrosion medium concentration with the weight loss of the carbon steel specimens at various test periods at room temperature

Fig. 2 .Fig. 3 .
Fig. 2. Variation of test period with the weight loss of the carbon steel specimens at various concentrations at 60 O C Fig 6.a.Carbon steel coated with Nano PVL, Nano cotton cellulose, Nano banana cellulose, Nano ZnO at 600 O C and Nano ZnO at 700 O C subjected to 0.05M sodium thio sulfate shown in Fig. 6b to 6e.The SEM resultsshowed that in the absence of inhibitor, more oxidized product in the metal surface with more damages.Where in the presence of inhibitor, there is little corrosion takes place in the surface due to its binding to the metal which visible in the SEM images.ZnO coating at 700 O C showed the best surface coverage.