Heavy metals in soils

In order to evaluate the effect of the functional group present in the ligand backbone towards corrosion inhibition performances, three Schiff-base molecules namely, (E)-4-((2-(2,4-dinitrophenyl)hydrazono)methyl)pyridine (L(1)), (E)-4-(2-(pyridin-4-ylmethylene)hydrazinyl)benzonitrile (L(2)) and (E)-4-((2-(2,4-dinitrophenyl)hydrazono)methyl)phenol (L(3)) were synthesized and used as corrosion inhibitors on mild steel in 1 M HCl medium. The corrosion inhibition effectiveness of the studied inhibitors was investigated by weight loss and several sophisticated analytical tools such as potentiodynamic polarization and electrochemical impedance spectroscopy measurements. Experimentally obtained results revealed that corrosion inhibition efficiencies followed the sequence: L(3) > L(1) > L(2). Electrochemical findings showed that inhibitors impart high resistance towards charge transfer across the metal-electrolyte interface and behaved as mixed type inhibitors. Scanning electron microscopy (SEM) was also employed to examine the protective film formed on the mild steel surface. The adsorption as well as inhibition ability of the inhibitor molecules on the mild steel surface was investigated by quantum chemical calculation and molecular dynamic (MD) simulation. In quantum chemical calculations, geometry optimized structures of the Schiff-base inhibitors, electron density distribution in HOMO and LUMO and Fukui indices of each atom were employed for their possible mode of interaction with the mild steel surfaces. MD simulations revealed that all the inhibitors molecules adsorbed in parallel orientation with respect to the Fe(110) surface.

Novel Schiff-base molecules as efficient corrosion inhibitors for mild steel surface in 1 M HCl medium: experimental and theoretical approach.

An overview on plant extracts as environmental sustainable and green corrosion inhibitors for metals and alloys in aggressive corrosive media

Inhibition of the corrosion of steel in HCl, H2SO4 solutions by bamboo leaf extract

A critical review on the recent studies on plant biomaterials as corrosion inhibitors for industrial metals

The inhibition of corrosion of aluminum in hydrochloric acid solutions by the ethanolic extract of the leaves of Ananas sativum was studied using weight loss and hydrogen evolution methods. It was found that the plant extract retarded the acid induced corrosion of aluminum. Inhibition efficiency increased with increasing concentration of the extract and temperature. Adsorption studies revealed that Langmuir adsorption isotherm is the best adsorption model applicable to the adsorption of A. sativum on aluminum surface. Activation parameters such as activation energies (E a), activation enthalpy (ΔH o), and activation entropy (ΔS o) were evaluated from the effect of temperature on the corrosion and inhibition processes.

Leaves extract of Ananas sativum as green corrosion inhibitor for aluminium in hydrochloric acid solutions

The corrosion inhibition of mild steel in HCl by pineapple leaves extract was studied using weight loss and hydrogen evolution methods at 30–60 °C. It was found that the pineapple leaves extract inhibited the acid induced corrosion of mild steel. The inhibition efficiency increases with increase in the extract concentration and with rise in temperature. Adsorption of the extract was found to obey Langmuir adsorption isotherm at all the concentrations and temperatures studied. The mechanism of chemical adsorption is proposed from the trend of inhibition efficiency with temperature. The proposed mechanism was also corroborated by kinetic and thermodynamic parameters obtained.

Inhibition of mild steel corrosion in HCl using pineapple leaves ( Ananas comosus L. ) extract

The atmospheric deposition of some heavy metals was investigated using lichen (Parmelia caperata) and moss (Polytrichum juniperinum, Calymperes erosum and Racopilum africanum) samples collected from two oil-producing host communities viz Eket and Ibeno Local Government Areas of Akwa Ibom State, Nigeria. Lichen and moss samples were analysed using atomic absorption spectrometry equipped with flame and graphite furnace after decomposition using acid digestion technique. The concentrations of heavy metals in lichen and moss samples ranged from 0.001 - 0.092 μg g −1 for cadmium (Cd); 0.004 - 8.793 μg g −1 for chromium (Cr); 0.989 - 1.950 μg g −1 for cobalt (Co); 2.350 - 110.760 μg g −1 for copper (Cu); 10.530 - 153.320 μg g −1 for manganese (Mn); 1.425 - 21.730 μg g −1 for nickel (Ni); 0.001 - 17.380 μg g −1 for lead (Pb), and 23.530 - 130.600 μg g −1 for zinc (Zn). The statistical significance of correlations between Cu-Pb, Cu-Zn, Pb-Ni and Mn-Zn concentrations confirmed anthropogenic sources mainly due to emissions from vehicular traffic, fossil fuel combustion, solid waste disposal and other local anthropogenic activities. In a direct comparison, some of the target heavy metals such as Cd, Cr, Mn, Ni and Zn were accumulated at higher concentrations in moss samples compared to lichen from the same sampling site. The results obtained reveal important contributions towards understanding of heavy metal deposition patterns and provide baseline data that can be used for potential identification of areas at risk from atmospheric heavy metals contamination in the region. The use of epiphytic lichens and mosses provides a cost-effective approach for monitoring regional atmospheric heavy metal contamination and may be effectively used in large scale air pollution monitoring programmer.

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Distribution of Some Atmospheric Heavy Metals in Lichen and Moss Samples Collected from Eket and Ibeno Local Government Areas of Akwa Ibom State, Nigeria

Concentration and chemical speciation for the determination of Cu, Zn, Ni, Pb and Cd from refuse dump soils using the optimized BCR sequential extraction procedure

I. I. Udousoro

Papers

Leaves extract of Ananas sativum as green corrosion inhibitor for aluminium in hydrochloric acid solutions

Inhibition of mild steel corrosion in HCl using pineapple leaves ( Ananas comosus L. ) extract

Distribution of Some Atmospheric Heavy Metals in Lichen and Moss Samples Collected from Eket and Ibeno Local Government Areas of Akwa Ibom State, Nigeria

Concentration and chemical speciation for the determination of Cu, Zn, Ni, Pb and Cd from refuse dump soils using the optimized BCR sequential extraction procedure

Fractionation of Cd, Cr, Pb and Ni in roadside soils of Uyo, Niger Delta Region: Nigeria using the optimized BCR sequential extraction technique