Physicochemical characterization and inhibitive performance evaluation of Commiphora kestingii gum exudate in acidic medium (original) (raw)
Related papers
The inhibition and adsorption properties of Commiphora africana gum for the corrosion of aluminium in hydrochloric acid (HCl) medium was investigated. Results obtained from GCMS analysis of the Commiphora africana gum indicated the presence of oleic acid (35.19%), hexadecanoic acid (16.09%), dihex-5-en-2-ylphalate, stearic acid (12.63%), (9Z,12E) –tetradeca-9, 12-dien-1-ol (6.73%) and 2-(hydroxymethyl)-2-nitropropane-1, 3-diol (26.53%). The gum was found to be a good adsorption inhibitor for the corrosion of aluminium in HCl solution. The adsorption of the inhibitor was spontaneous, exothermic and best fitted the Langmuir adsorption model. From the pattern of the variation of inhibition efficiency with temperature, values of the activation and free energies were lower than their respective threshold values, obedient of the mechanism of physical adsorption was upheld for the inhibitor. Results obtained from the quantum chemical study and from the FTIR analysis of the corrosion products revealed that the corrosion active constituents of the gums are dihex-5-en-2-yl phthalate and 2-(hydroxymethyl)-2-nitropropane-1,3-diol.
Commiphora pedunculata gum as a green inhibitor for the corrosion of aluminium alloy in 0.1 M HCl
Research on Chemical Intermediates, 2013
The effect of Commiphora pedunculata (CP) gum on the inhibition of the corrosion of aluminum alloy AA 3001) in solutions of HCl was investigated using gravimetric and thermometric methods of monitoring corrosion. The results obtained indicated that CP gum is a good adsorption inhibitor for the corrosion of aluminum in solutions of HCl. The inhibition efficiency of CP gum was found to increase with an increase in concentration but to decrease with increasing temperature. The adsorption of CP gum on the surface of aluminum was found to be endothermic, spontaneous and to support the mechanism of physical adsorption. The Langmuir adsorption model has been used to describe the adsorption characteristics of CP gum on aluminum surface.
The inhibitive effect of exudate gum from Dacroydes edulis in the corrosion of aluminium in HCl solutions was studied using weight loss and thermometric methods at 30-60 o C. The results reveal that the exudate gum acts as an inhibitor for corrosion of aluminium in HCl solution. The inhibition efficiency increases with an increase in the concentration of the exudate gum but decreases with increase in temperature. The Temkim adsorption isotherm was tested for its fit to the experimental data. The result confirms that the corrosion inhibition of the exudate gum from DE is attributed to the adsorption of molecules of phytochemicals present in the exudate gum on the surface of the metal. The free energies and equilibrium constant for the adsorption process were determined. A mechanism of physical adsorption is proposed..
Chemical constituents and functional groups in Ficus thonningii gum was determined using GCMS and FTIR spectropho-tometer, respectively. The GCMS spectrum of Ficus thonningii gum showed the presence of useful organic chemicals. The gum is mildly acidic, tasteless, yellowish in colour, insoluble in chloroform and acetone but soluble in water and ethanol. Based on its chemical constituents, the corrosion inhibition potential of the gum was investigated and it was found that the gum acted as an adsorption inhibitor for the corrosion of aluminium in solution of HCl. The adsorption of the gum on the surface of aluminium is spontaneous, exothermic and proceeded through the initial mechanism of physical adsorption. Deviation of the adsorption of the gum from the ideal Langmuir adsorption isotherm and the nature of adsorption were accounted for by Frumkin, El Awardy and Dubinin-Radushkevich (D-RIM) adsorption isotherms. The study provides information on the physicochemical constituents of the gum, functional groups associated with the gum and its application as a green corrosion inhibitor. Ficus thonnigii gum as a green corrosion inhibitor may find possible application in metal surface anoding and surface coatings.
Adsorption and Inhibitive properties of Ficus sycomorus gum on the corrosion of aluminium in HCl
Ficus sycomorus gum was tapped, collected and purified. The adsorption properties and inhibition potentials of the gum on aluminium in HCl was studied at different temperature of 303K and 333K using gravimetric method. The inhibition efficiencies of the gum increase with increase in concentration and decrease with increase in temperature and period of immersion. Values of activation energy of the inhibited corrosion reaction of aluminium were greater than the value obtained for the blank. Thermodynamic consideration revealed that adsorption of the inhibitor on aluminium surface was first order, exothermic, spontaneous and was through the mechanism of physical adsorption. The adsorption characteristic of the inhibitor was best described by the Langmuir adsorption isotherm.
Portugaliae Electrochimica Acta, 2007
Exudates gums from Pachylobus edulis (PE) and Raphia hookeri (RH) were evaluated as corrosion inhibitors for aluminium in HCl using weight loss and thermometric measurements at 30 -60 o C. The exudates were found to retard corrosion rate of aluminium. The inhibition efficiency (%1) increased with increase in concentration of the exudates. Increase in temperature increased the corrosion rate in the absence and presence of inhibitors but decreased the inhibition efficiency. Both PE and RH exudate gums were found to obey Temkin adsorption isotherm and Kinetic-Thermodynamic Model of El-Awady et al. at all the concentrations and temperatures studied. Phenomenon of physical adsorption is proposed from the activation parameters obtained. Thermodynamic parameters reveal that the adsorption process is spontaneous. Exudate gum from RH was found to be a better inhibitor than PE.
Examination of the physical (colour, odour, pH, solubility in various solvent) and chemical (GCMS and FTIR) characteristics of Ficus benjamina gum revealed that the gum is yellowish in colour, mildly acidic and ionic in nature. Major constituents of the gums were found to be sucrose and d-glucose, which constituted 60.92 % of its chemical constituents while various carboxylic acids (albietic acid (1.00 %); hexadecanoic acid (4.41 %); 9-octadecanoic acid (1.00 %), stearic acid (3.01 %); oleic acid (0.10 %); octadecanoic acid (9.12 %) and 6,13-pentacenequinone (20.43 %) accounted for the remaining constituents. Functional groups identified in the gum were found to be those typical for other carbohydrates. From the knowledge of the chemical structures of compounds that constitutes the gum, the corrosion inhibition potentials of the gum was ascertained and from weight loss analysis, the gum was found to be an active inhibitor against the corrosion of aluminum in solutions of tetraoxosulphate (VI) acid. The gum acted as an adsorption inhibitor that favours the mechanism of chemical adsorption and supported the Frumkin and Dubinin-Radushkevich adsorption models.
The anti-corrosive effect of Pachylobus edulis exudate gum in combination with halides ions (Cl -, Brand I -) for aluminium corrosion in HCl was studied at temperature range of 30-60 o C using weight loss method. Results obtained showed that the naturally occurring exudate gum acts as an inhibitor for aluminium corrosion in acidic environment. Inhibition efficiency (%I) increases with increase in concentration of the exudate gum and synergistically increased to a considerable extent on the addition of the halide ions. The increase in inhibition efficiency (%I) and surface coverage (θ) in the presence of the halides was found to be in the order I -> Br -> Clwhich indicates that the radii as well as electronegativity of the halide ions play a significant role in the adsorption process. Pachylobus edulis exudate gum obeys Temkin adsorption isotherm. Phenomenon of physical adsorption is proposed from the values of kinetic and thermodynamic parameters obtained. The values of synergism parameter (S 1 ) obtained for the halides are greater than unity suggesting that the enhanced inhibition efficiency of the P. edulis caused by the addition of the halide ions is only due to synergistic effect.
Corrosion inhibition potential of daniella oliverri gum exudate for mild steel in acidic medium
International Journal of Electrochemical Science, 2012
Physicochemical parameters of Daniella olliverri (DO) gum exudates were analyzed and the results indicated that the gum is acidic, brownish in colour, ionic and highly soluble in water but insoluble in acetone, chloroform and ethanol. GCMS spectrum of the gum indicated the presence of sucrose, dihex-5-en-2-yl phthalate, stearic acid, 2,6-dimethyl-4-nitrophenol and (E)-hexadec-9-enoic acid. Corrosion inhibition potential of the gum was investigated using weight loss and FTIR methods. Daniella olliverri gum has been found to be a good inhibitor for the corrosion of mild steel in HCl solution. Corrosion inhibition properties of the gum is attributed to the presence of aromatic, suitable functional groups and heteroatoms in its chemical constituents, which facilitated its adsorption. The adsorption of the gum on the surface of the metal was found to be endothermic, spontaneous and supported the mechanism of physical adsorption. The results obtained obeyed the Langmuir adsorption isotherm model.
International Journal of Metals, 2015
A comparative study of the inhibitory potentials of gum exudates from Albizia ferruginea (AF) and Khaya senegalensis (KS) on the corrosion of mild steel in HCl medium was investigated using weight loss and gasometric method. The active chemical constituents of the gum were elucidated using GC-MS while FTIR was used to identify the bonds/functional groups in the gums. The two gum exudates were found to be good corrosion inhibitors for mild steel in acidic medium. On comparison, maximum inhibition efficiency was found in Khaya senegalensis with 82.56% inhibition efficiency at 0.5% g/L concentration of the gum. This may be due to the fact that more compounds with heteroatoms were identified in the GCMS spectrum of KS gum compared to the AF gum. The presence of such compounds may have enhanced their adsorption on the metal surface and thereby blocking the surface and protecting the metal from corrosion. The adsorption of the inhibitors was found to be exothermic and spontaneous and fitt...