Neem Leaf Extract as a Corrosion Inhibitor on Mild Steel in Acidic Solution

Abstract

The influence of neem leaf extract on corrosion inhibition of mild steel in 0.1 M HCl solution was studied using the weight loss method. Neem leaf extract which contains the double bond, carbonyl groups, and aromatic rings functional group as shown by the GCMS, phytochemical test, and FTIR analyses is one of the good natural plant extract that can be used as corrosion inhibitor. The weight loss on surface of mild steel at various inhibitor concentrations was determined. The highest inhibition efficiency of 93.24% was achieved using the neem leaf extract as corrosion inhibitor. Adsorption mechanism was investigated using Langmuir, Temkin, and Freundlich isotherms. Inhibitor adherence on the mild steel surface was spontaneous with the negative Gibb’s free energy value obtained. The mixed type adsorption mechanism (physisorption and chemisorption) is proposed for the inhibitor adsorption on mild steel surface. The inhibitor was adsorbed on the mild steel surface through adsorption of the phytochemical components on the surface of mild steel which protects the metal surface from corroding. The corrosion rate decreases from 0.001 to 0.0002MPY with increase in inhibitor concentrations and exposure time.

Crude Alkaloid and Saponin Extracts of Agrimonia eupatoria Plant as Control Measure in Stainless Steel Corrosion in Hydrogen Tetraoxosulphate (VI) Acid Rich Area

“…The surface coverage (θ) values for different concentrations of the inhibitors in H2SO4 medium were evaluated using the weight loss data. The data were tested graphically to find a suitable adsorption isotherm to describe the adsorption characteristics of the extracts according to several authors [32][33][34][35][36]. A plot of Log (C/Ѳ) against Log C (Fig.…”

Batch and continuous fixed bed adsorption of heavy metals removal using activated charcoal from neem (Azadirachta indica) leaf powder

“…12 . Previously neem leaf powder was utilized as an adsorbent and corrosion inhibitor [13][14][15][16] . The sorption-desorption process is required to reduce solid waste pollution load and cost effective process 9 .…”

Inhibition Efficiency of Eco-friendly Green Inhibitors (Ocimum tenuiflorum Phytocompounds) on Corrosion of High Carbon Steel in HCl Environment using Thermometric and Electrochemical Methods

“…This result is in agreement with that of thermometric measurements. These observations are indicative of the fact that addition of AEOTR and FEOTR to 1 M HCl solution has reduced the anodic dissolution and the cathodic hydrogen evolution reaction of stainless steel in the acid medium, hence functioning as mixed type corrosion inhibitors [1,5,[14][15][16][17].…”

“…In the literature, the value of ΔG 0 ads equal to -20 kJmol -1 or less is taken to indicate physisorption involving electrostatic interaction between charged molecules whereas those in the order of -40 kJmol -1 or more is interpreted as chemisorption involving charge sharing or transfer from the inhibitors to the metal surface to form a kind of coordinate bond [11,5,15,[29][30][31][32]. From the values of ΔG 0 ads obtained in this present work, it can be deduced that adsorption mechanism of both inhibitors on high carbon steel surface may involve physisorption [14][15][16][17][18][19][20][21][22][23][24][25][26].…”

“…where Rc is the corrosion rate, Ea is the apparent effective activation energy, R is the general gas constant, and A is the Arrhenius preexponential factor [10,[14][15][16][17][18][19]. Calculated values of activation energy between 303 K, 318 K and 333 K were obtained from the slope of Fig.…”