Mass-loss Technique Research Articles

Phytochemical screening and corrosion inhibitive behavior of Pterolobium hexapetalum and Celosia argentea plant extracts on mild steel in industrial water medium

Preliminary phytochemical screening was carried out for methanolic extracts of Pterolobium hexapetalum (PH) and Celosia argentea (CA). Methanolic extracts of PH and CA were studied as corrosion inhibitors for mild steel in industrial water medium using mass loss and electrochemical techniques. The adsorption of both PH and CA extracts on mild steel surface followed Langmuir isotherm. The electrochemical impedance spectroscopy (EIS) measurements showed that the charge transfer resistance increases with increasing concentration of extracts. Various thermodynamic parameters were evaluated and discussed. Scanning electron microscopy (SEM) was used to analyze the surface adsorbed film. Further, antioxidant activity of the plant extracts was determined and correlated with the results obtained with inhibition efficiency.

Influence of some synthesized pyrimidine derivatives on corrosion inhibition of mild steel in hydrochloric acid medium

The influence of four newly synthesized pyrimidine derivatives on the corrosion inhibition of mild steel in 0.5 M HCl solution is studied using mass loss and electrochemical techniques. The corrosion rate was found to depend on concentration and temperature of the medium. Adsorption of all the four inhibitors obeys Langmuir isotherm model. Polarization curves indicated that the studied inhibitors are of mixed type. Electrochemical impedance spectroscopy explains the mechanism of inhibitor’s action. Various activation and adsorption thermodynamic parameters were calculated and discussed. The results obtained from weight loss and electrochemical studies are in good agreement with each other. The variation in inhibitive efficiency mainly depends on the type and nature of the substituents present in the inhibitor molecule.

Synthesis of New Pyridine Based 1,3,4-Oxadiazole Derivatives and their Corrosion Inhibition Performance on Mild Steel in 0.5 M Hydrochloric Acid

The influence of three newly synthesized oxadiazole derivatives on the corrosion inhibition of mild steel in 0.5 M HCl solution was studied using mass loss and electrochemical techniques. The corrosion rate decreased with increasing concentration of inhibitors and increased with increase in temperature of the medium. Adsorption of the all the three inhibitors obeyed the Langmuir isotherm model. Polarization curves indicated that the inhibitors are of mixed type. Electrochemical impedance spectroscopy measurements explained the mechanism of action of inhibitors. Various activation and adsorption thermodynamic parameters were calculated. The surface adsorbed film was characterized by scanning electron microscopy (SEM) and energy dispersive analysis of X-ray (EDAX). The electronic properties of the inhibitors were obtained from AM1 semiempirical quantum chemical approach. Excellent correlation was found between theoretical and experimental results.

Vaporization of the prototypical ionic liquid BMImNTf₂ under equilibrium conditions: a multitechnique study.

The vaporization behaviour and thermodynamics of the ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethyl)sulfonylimide (BMImNTf2) were studied by combining the Knudsen Effusion Mass Loss (KEML) and Knudsen Effusion Mass Spectrometry (KEMS) techniques. KEML studies were carried out in a large temperature range (398-567) K by using effusion orifices with 0.3, 1, and 3 mm diameters. The vapor pressures so measured revealed no kinetically hindered vaporization effects and provided second-law vaporization enthalpies at the mean experimental temperatures in close agreement with literature. By exploiting the large temperature range covered, the heat capacity change associated with vaporization was estimated, resulting in a value of -66.8 J K(-1) mol(-1), much lower than that predicted from calorimetric measurements on the liquid phase and theoretical calculations on the gas phase. The conversion of the high temperature vaporization enthalpy to 298 K was discussed and the value Δ(l)(g)H(m)(298 K) = (128.6 ± 1.3) kJ mol(-1) assessed on the basis of data from literature and present work. Vapor pressure data were also processed by the third-law procedure using different estimations for the auxiliary thermal functions, and a Δ(l)(g)H(m)(298 K) consistent with the assessed value was obtained, although the overall agreement is sensitive to the accuracy of heat capacity data. KEMS measurements were carried out in the lower temperature range (393-467) K and showed that the largely prevailing ion species is BMIm(+), supporting the common view of BMImNTf2 vaporizing as individual, neutral ion pairs also under equilibrium conditions. By monitoring the mass spectrometric signal of this ion as a function of temperature, a second-law Δ(l)(g)H(m)(298 K) of 129.4 ± 7.3 kJ mol(-1) was obtained, well consistent with KEML and literature results. Finally, by combining KEML and KEMS measurements, the electron impact ionization cross section of BMIm(+) was estimated.

Corrosion Inhibition of Mild Steel in Acidic Medium by Salvadora Persica (Miswak) – Part 1: in Sulfamic Acid

Aqueous root extract of Salvadora persica (ARESP) was studied as a new green corrosion inhibitor for mild steel (MS) in 1.0 N sulfamic acid solutions by using mass loss and electrochemical techniques at temperatures ranging from 303 to 333 K. Appropriate equivalent circuit model was used to calculate the impedance parameters. The electrochemical impedance spectroscopy (EIS) measurements showed that the charge transfer resistance increases with an increase in the concentration of ARESP. The results obtained from the new technique electrochemical frequency modulation (EFM) indicated that ARESP acts as mixed type of inhibitor. The protection efficiency increases with the increase in inhibitor concentration and decreases with temperature. The results of the study revealed that ARESP inhibits the corrosion of MS through adsorption process following Temkin adsorption isotherm model. The apparent activation energy (Ea) and the equilibrium constant of adsorption (Kads) were calculated. Scanning electron microscopy (SEM) was used to investigate the adsorbed film of ARESP on the steel surface.

Corrosion inhibition efficiency and adsorption characteristics of some Schiff bases at mild steel/hydrochloric acid interface

The corrosion inhibition efficiency of newly synthesized Schiff bases was investigated for mild steel (MS) corrosion in 0.5M HCl medium using mass loss and electrochemical techniques. The potentiodynamic polarization results indicated that all the studied inhibitors act as mixed type. The adsorption process on MS surface obeyed Langmuir isotherm. The associated activation parameters and thermodynamic data of adsorption were evaluated and discussed. The adsorbed film formed on the metal surface was characterized by SEM and IR-spectroscopy. Further, antioxidant activity of the Schiff bases was determined and correlated the results obtained with inhibition efficiency.

The Effect ofAchyranthes asperaExtracts on Mild Steel Corrosion in Industrial Water Medium

Achyranthes aspera(AA) extracts were studied as corrosion inhibitor for mild steel (MS) in industrial water medium using mass loss and electrochemical techniques. The results of the study revealed that AA extracts inhibit MS corrosion through adsorption process following Langmuir adsorption isotherm model. The protection efficiency increased with increase in inhibitor concentration and decreased with temperature. The electrochemical impedance spectroscopy (EIS) measurements showed that the charge transfer resistance increases with increase in the concentration of AA extracts. The polarization curves obtained indicate that AA extracts act as mixed type of inhibitor. Scanning electron microscopy (SEM) was used to analyze the surface adsorbed film.

Thermal investigations of SmFeTeO6 and SmCrTeO6 compounds

SmFeTeO6 and SmCrTeO6 were synthesized by heating the respective oxides in molar quantities and characterized by X-ray technique. Thermogravimetric studies suggested that SmFeTeO6 and SmCrTeO6 vapourize incongruently according to the reactions: $$ \begin{aligned} {\text{SmFeTeO}}_{ 6}{({\text{s}})} & \to {\text{SmFeO}}_{ 3} {( {\text{s}})} + {\text{TeO}}_{ 2} {( {\text{g}})} + \left( { 1/ 2} \right){\text{O}}_{ 2}{( {\text{g}})} \\ {\text{SmCrTeO}}_{ 6} {( {\text{s}})} & \to {\text{SmCrO}}_{ 3} {( {\text{s}})} + {\text{TeO}}_{ 2}{( {\text{g}})} + \left( { 1/ 2} \right){\text{O}}_{ 2}{( {\text{g}})}. \\ \end{aligned} $$ X-ray diffraction data of both the compounds have been indexed on the hexagonal system. Partial pressures of TeO2(g) were measured over SmFeO3(s) and SmCrO3(s) by employing the Knudsen effusion mass loss technique. The standard Gibbs free energy of formation of (ΔfG°) SmFeTeO6(s) and SmCrTeO6(s) were obtained from partial pressures and represented by the following relations: $$\Updelta_{\text{f}} G^{\circ} \left( {{\text{SmFeTeO}}_{6}{( {{\text{s}},\,T})}} \right) \pm 2 5\,{\text{kJ}}\,{\text{mol}}^{ - 1} = - 1 5 1. 6 5+ 0. 1 5\left(T \right)\quad \left( 1 ,0 90{-} 1,1 80\,{\text{K}} \right) \\ \Updelta_{\text{f}} G^{\circ } \left( {{\text{SmCrTeO}}_{ 6} {( {{\text{s}},\,T})}} \right) \pm 2 5\,{\text{kJ}}\,{\text{mole}}^{ - 1} = - 2 5 2. 8 6+ 0. 1 2(T)\quad \left( { 1,100 {-} 1 , 1 7 5\,{\text{K}}} \right).$$

Corrosion Inhibition of Mild Steel in Nitric Acid Media by some Schiff Bases Derived from Anisalidine

Corrosion inhibition performance of mild steel in nitric acid solution containing different concentration of anisalidine derivative Schiff bases viz. N- (4-nitro phenyl) p-anisalidine (SB1), N- (4-chloro phenyl) p-anisalidine (SB2), N- (4-phenyl) p-anisalidine (SB3), N- (4-methoxy phenyl) p-anisalidine (SB4), N- (4-hydroxy phenyl) p-anisalidine (SB5) has been investigated using mass loss, thermometric and potentiostate polarization technique. Inhibition efficiencies of Schiff bases have been evaluated at different acid strength. The inhibition efficiency was found larger than their parent amines. Inhibition efficiencies of synthesized Schiff bases increase with inhibitor concentration. Inhibition efficiency increases up to 98.32% with ansalidine derivative Schiff base.

Inhibition Behaviour of Some Isonicotinic Acid Hydrazides on the Corrosion of Mild Steel in Hydrochloric Acid Solution

New corrosion inhibitors, namely, isonicotinic acid (1H-indol-3-yl-methylene)hydrazide (INIMH) and isonicotinic acid (1H-pyrrol-2-yl-methylene)hydrazide (INPMH), have been synthesized, and their inhibitive characteristics for the corrosion of mild steel in 0.5 M HCl were investigated by mass loss and electrochemical techniques. The structures of the synthesized compounds were confirmed using spectral studies. Potentiodynamic polarization studies revealed that the investigated inhibitors are of mixed type. Various thermodynamic parameters were evaluated. Langmuir adsorption isotherm was found to be the best description for both inhibitors. FTIR spectra, energy dispersive X-ray spectroscopy (EDX), and scanning electron microscopy (SEM) were performed to characterize the passive film on the metal surface.

Ca–Mg–Zn bulk metallic glasses as bioresorbable metals

A series of six unique Ca-based bulk metallic glasses were synthesized and characterized. The glasses were designed to consist solely of the biocompatible elements Ca, Mg and Zn, with the view to their potential use as bioresorbable metals for orthopaedic applications. The alloys had a critical casting thickness of up to 4.5mm. Mechanical and thermophysical testing revealed a Young’s modulus (stiffness) of ∼40GPa. Glass transition temperatures ranged from 119 to 129°C, above which the alloys can be formed like a thermoplastic polymer. In vitro biocorrosion testing using a combination of polarization and mass loss techniques revealed that the corrosion rate of these alloys is relatively rapid, although, in some cases, it may be tailored through alloy composition.

Film Formation and Anticorrosive Behavior of Zn-ZSM-5 Nano-Sized Zeolite Composite Coatings

The zinc- Zeolite Socony Mobil-Five nano-particles (Zn-ZSM-5 NPs) composite was prepared and applied successfully as a new coating material to improve the corrosion resistance of steel. The corrosion type and quality of both pure zinc and our new coating material, Zn-ZSM-5 NPs, were studied using mass loss, impedance and electro-chemical polarization techniques in a sodium chloride solution. Obtained results affirm that Zn-ZSM-5 NPs are non-permeable and their corrosion resistance is higher than the pure zinc. The surface morphology of our newly synthesized coating material, Zn-ZSM-5 NPs, was investigated using SEM and X-ray diffraction and the smaller grain size was observed in comparison with the pure zinc coating. Keyword: Zeolite Socony Mobil-Five (ZSM-5), Zeolite nano-particles, Corrosion, Composite coating, zinc.

Adsorption and Inhibitive Effects of 2-Thiobenzylbenzimidazole (TBBI) at Aluminium Alloy AA3003/ 1M Hydrochloric Acid Interface

The interfacial behavior of 2-Thiobenzylbenzimidazole (TBBI) between aluminium alloy AA 3003 and 1M hydrochloric acid solution was investigated by mass loss technique. Mass loss is concentration and temperature dependent. The influence of temperature has been studied in the absence and in presence of TBBI in the hydrochloric solution in the range 35-55oC. Adsorption isotherms models including Langmuir, Temkin, Freundlich and El-Awady were tested. It was found that the inhibitor adsorbs on the metal according to the modified Langmuir adsorption isotherm. Some thermodynamic adsorption parameters (�G ° �H ° ,�S ° ) as well as activation parameters including apparent activation energy (Ea), change in activation enthalpy (� � ) and change in activation entropy (� � ) have been calculated and analyzed. Furthermore the DubininRaduskevitch model has been used to distinguish between chemisorption and physisorption. The properties most relevant to the potential action as a corrosion inhibitor of TBBI have been calculated: highest occupied molecular orbital energy (EHOMO), lowest unoccupied molecular orbital energy (ELUMO), energy gap (ΔE), dipole moment (µ) and charges on the adsorption centers (S, N) and C atoms in benzimidazole and benzyl rings. These calculations were performed using the Gaussian Research Article

Inhibiting Properties of Morpholine as Corrosion Inhibitor for Mild Steel in 2N Sulphuric Acid and Phosphoric Acid Medium

The inhibition effect of morpholine on the corrosion of mild steel in 2N sulphuric acid and phosphoric acid has been studied by mass loss and polarization techniques between 302K and 333K. The inhibition efficiency increased with increase in concentration. The corrosion rate increased with increase in temperature and decreased with increase in concentration of inhibitor compared to blank. The adsorption of inhibitor on the mild steel surface has been found to obey Temkin′s adsorption isotherm. Potentiostatic polarization results reveal that morpholine act as mixed type inhibitor. The values of activation energy (Ea), free energy of adsorption (∆Gads), enthalpy of adsorption (∆H), and entropy of adsorption (∆S) were also calculated.

Determination of sublimation rate of 2,4,6-trinitrotoluene (TNT) nano thin films using UV-absorbance spectroscopy

We report the in situ measurements of the sublimation rate and activation energy of continuous nanofilms of 2,4,6-trinitrotoluene (TNT) in air using UV absorbance spectroscopy. The films were prepared using acetone-dissolved TNT by simple spin coating deposition technique. Unlike traditional mass loss techniques, this new method is independent of the surface area of the sample which contributes to errors in determining physical parameters accurately in both bulk and thin films of materials. The calculated activation energy and temperature-dependent sublimation rates agree well with the reported values for TNT thin films. The results suggest that UV absorbance spectroscopy is an efficient tool in measuring thermodynamic properties in the nanometer scale for materials with absorbance in the UV region of the electromagnetic spectrum.

Development and test of a new Knudsen effusion apparatus for the measurement of low vapour pressures

A new Knudsen effusion apparatus based on the mass-loss technique was developed. The apparatus was designed for the measurement of vapour pressures below 1 Pa, at temperatures between 250 K and 470 K, using simultaneously up to seven effusion cells. The quality of the results obtained with this new apparatus was verified through the study of two reference compounds, anthracene and phenanthrene. Both the measured vapour pressures and the derived standard molar enthalpies of sublimation are in excellent agreement with values available in the literature for these compounds.

Inhibition of Zinc Corrosion by Some Benzaldehyde Derivatives in HCl Solution

The effect of some benzaldehyde derivatives on the corrosion of zinc in 0.5 M HCl solution is studied in this article using mass loss, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS) techniques. The percentage inhibition efficiency (%In) was found to increase with increasing concentration of the inhibitor and with decreasing temperature. Polarization studies indicated that all of the compounds studied are mixed-type inhibitors. The inhibitive action of these benzaldehyde derivatives has been discussed in view of the adsorption on the zinc surface. The adsorption process follows Temkin’s isotherm. The addition of KSCN, KI, and KBr to benzaldehyde derivatives has enhanced the inhibition efficiency because of synergistic effect. The mechanism of inhibition process is discussed in the light of the chemical structures of the investigated inhibitors.

Energetics of 1-(aminophenyl)pyrroles: A joint calorimetric and computational study

Abstract Static bomb calorimetry and the Knudsen effusion mass-loss technique were used to derive, respectively, the standard (p° = 0.1 MPa) molar enthalpy of formation, in the crystalline phase, Δ f H m ∘ ( cr ) , and the standard molar enthalpy of sublimation, at T = 298.15 K, Δ cr g H m ∘ , of 1-(2-aminophenyl)pyrrole. These experiments allowed the determination of its standard (p° = 0.1 MPa) molar enthalpy of formation, in the gaseous phase, Δ f H m ∘ ( g ) , at T = 298.15 K, as (224.1 ± 2.4) kJ · mol−1. The gas-phase enthalpy of formation of 1-(2-aminophenyl)pyrrole was also estimated by G3(MP2)//B3LYP calculations, which were further extended to the (aminophenyl)pyrroles that were not studied experimentally. Experimental and theoretical results are in very good agreement.

Standard molar enthalpies of formation of 3′- and 4′-nitroacetophenones

The standard ( p° = 0.1 MPa) molar enthalpies of formation, in the condensed phase, of 3′- and 4′-nitroacetophenones, presented in this work, were obtained from measurements of their combustion energies, at T = 298.15 K, using a static bomb calorimeter. The vapor pressures of the two crystalline 3′- and 4′-nitroacetophenones were measured as a function of temperature by the Knudsen effusion mass loss technique. The standard molar enthalpies of sublimation, at T = 298.15 K, were derived from the Clausius–Clapeyron equation. The standard molar enthalpies, entropies, and Gibbs functions of sublimation, at T = 298.15 K, were calculated for the two compounds. The experimental values obtained were used to calculate the standard molar enthalpies of formation of 3′- and 4′-nitroacetophenones, in the gaseous phase, as Δ f H m ∘ (g) = - ( 99.4 ± 1.6 ) kJ · mol - 1 and Δ f H m ∘ (g) = - ( 99.1 ± 1.7 ) kJ · mol - 1 , respectively, and these derived values are analyzed in terms of structural enthalpic increments.

Corrosion Inhibition of Aqueous Extract of Cocos nucifera - Coconut Palm - Petiole Extract from Destructive Distillation for the Corrosion of Mild Steel in Acidic Medium

The inhibitive effect and adsorption properties of petiole extract obtained from destructive distillation of cocos nucifera for the corrosion of mild steel in 0.5 M H 2SO 4 and 1 M HCl were investigated using mass loss, polarization and electrochemical impedance techniques of monitoring corrosion. The results obtained indicate that petiole extract of cocos nucifera behaves as good inhibitor for the corrosion of mild steel in 0.5 M H 2SO 4 and 1 M HCl. Activation energy of thermodynamic parameter was evaluated from temperature studies result. The adsorption of the inhibitor on mild steel surface was found to be spontaneous, endothermic and consistent with the assumptions of Langmuir adsorption isotherm. The electrochemical measurements reveal that the petiole extract behaved like mixed type inhibitor. Efforts are made to analyze the effectiveness of petiole extract of coconut palm in industrial processes.