Adsorption of metal ions and dyes from water by cashew nut testa tannin resin (CATAR) was studied... more Adsorption of metal ions and dyes from water by cashew nut testa tannin resin (CATAR) was studied and the effects of temperature, initial pH, initial concentration and time were investigated. Scanning electron microscopy (SEM) and infrared spectroscopy (FTIR) reveal effective adsorption processes. Kinetic studies show that CATAR adsorption is complex and thermodynamic parameters calculated reveal spontaneous and endothermic adsorption of studied pollutants onto CATAR. The use of CATAR as an alternative adsorbent is proposed considering that of simulated wastewaters gave excellent removal performances of 94.0% (Cd ions), 99.4% (Cu ions) and 97.1% (Pb ions) at pH of 6 and 303 K using amount of CATAR. Removal performances obtained for simulated dye wastewaters using CATAR at similar conditions for removal of metal ions gave 71.1%, 79.2% and 86.6%, respectively for crystal violet, methylene blue and malachite green.
Metal deterioration over time is a process known as corrosion, an electrochemical process, which ... more Metal deterioration over time is a process known as corrosion, an electrochemical process, which can occur by surface chemical actions on metals by its environment. Metal corrosion have great economic, security, and environmental consequences, and its control is a major research area in corrosion science. Amongst the different corrosion protecting approaches, the use of corrosion inhibitors and protective coatings have attracted enormous research interest in this area of scholasticism. This has necessitated the computational and electrochemical investigations of aluminium corrosion inhibitive potentials of some compounds in 1M HCl. Metal free (5_H2), ClGa(III) (5_Ga) and Co(II) (5_Co) tetrakis(4-acetamidophenoxy)phthalocyanines as well as Co(II) 2,9,16-tris(4-(tert-butyl)phenoxy)-23-(pyridin-4-yloxy)phthalocyanine (6) and Co(II) 2,9,16,24-tetrakis(4-(tert-butyl)phenoxy)phthalocyanine (7) were synthesized for the first time and studied for corrosion inhibition. The reported ClGa(III)...
Abstract N -(2-chloroethyl)morpholine-4-carboxamide (NCMC), N -(2-chloroethyl)tiomorpholine-4-car... more Abstract N -(2-chloroethyl)morpholine-4-carboxamide (NCMC), N -(2-chloroethyl)tiomorpholine-4-carboxamide (NCTC) and N , N -bis(2-chloroethyl)piperazine-1,4-dicarboxamide (NCPD) were studied as corrosion inhibitors for mild steel using atomic absorption spectroscopy (AAS) and gravimetry and thermometry. Results obtained from the three techniques are similar and reveal that the compounds inhibit mild steel corrosion. The inhibition efficiencies increased from 35.6% to 74.9% (NCMC), 44.5% to 82.4% (NCPD) and 52.6% to 90.1% (NCTC) at 30 °C when the inhibitor concentrations increased from 10 μM to 50 μM. The maximum inhibition efficiency values (at 50 μM) decreased to 46.6%, 58.1% and 61.2% for NCMC, NCPD and NCTC respectively, when the temperature was raised to 50 °C. The decrease in inhibition efficiency with increase in temperature suggested predominant physisorption mechanism in metal/inhibitor interactions. The formation of protective films of NCMC, NCPD and NCTC molecules on mild steel surface were confirmed by FTIR and XRD. The order of inhibitive strengths of the molecules is NCTC > NCPD > NCMC. Quantum chemical calculations revealed the prospective sites through which the molecules can interact with mild steel surface and some quantum chemically derived parameters were used to corroborate experimental.
Human African trypanosomiasis, also known as sleeping sickness, is caused by the single-celled ki... more Human African trypanosomiasis, also known as sleeping sickness, is caused by the single-celled kinetoplastid parasite Trypanosoma brucei transmitted to humans by infected tsetse flies. The disease threatens millions of people. Currently available treatment options are faced with some important challenges. In this work, a total of eighty-seven (87) morpholine derivatives were evaluated for drug-likeness based on Lipinski’s rule of five and their ability to inhibit the activities of trypanosomal triosephosphate isomerase was assessed by molecular docking and calculation of free energy of binding. Analysis of the results revealed that 97.7 % of the dataset complied with Lipinski’s criteria for a molecule to be orally bioavailable. Also, 50.0 % of the studied compounds had a good total polar surface area profile, a parameter which is of great importance for the treatment of stage two Trypanosoma infections. Docking studies showed that all the dataset demonstrated affinity for triosephosphate isomerase. Moreover, six morpholines scored higher than the co-crystallized inhibitor of triosephosphate isomerase (2-phosphoglycerate). These derivatives inhibited the activity of triosephosphate isomerase by making significant interactions with Glu 167, Val 214, 233, Asn 11, Lys 13, Ser 213, Leu 232, Ile 172, Gly 211, 212, 234, 235 and His 92 in the active site of the protein. Furthermore, besides the acceptable pharmacokinetic profiles of the six morpholines, they also showed inhibitory potencies toward four other validated antitrypanosomal drug targets. In view of the foregoing findings, we propose that the six morpholine derivatives be given worthwhile attention to develop them into novel trypanocides.
Journal of Environmental Chemical Engineering, 2016
Beyond systematic entrepreneurship: The role of intuition in experience innovation In this paper ... more Beyond systematic entrepreneurship: The role of intuition in experience innovation In this paper we start from the conception of experience innovation as originally proposed by Prahalad and Ramaswamy (2003) since this approach seems to contradict the assumption that entrepreneurship is a systematic behaviour based on concept and theory rather than a personality trait based on intuition (see Drucker, 2006). We attend to the questions: What is the role of creative intuition in experience innovation? and How should be entrepreneurship studied in future? In economics, experiences are distinct economic values in the form of personally engaging events that remain memorable for the customers (Pine II & Gilmore, 2000) but they function according to a quite different set of internally consistent assumptions of value creation compared to services and products (Prahalad, 2004). Hence, value is created at the point of exchange, and services and products are merely regarded as carriers of experiences (see Prahalad, 2004: 173). Innovation remains a consistent factor in this economic shift from services to experiences, but here innovation is focused on experiences rather than on products or services. Experience innovation aims at nudging the co-creation of experience spaces in which "personalized, evolvable experiences are the goal, and products and services evolve as a means to that end" (Prahalad & Ramaswamy, 2003: 18). Traditionally entrepreneurship and innovation go hand in hand because the latter is believed to have its source in the Unternehmergeist (entrepreneurial spirit). However, Schumpeter (1911: 88-89) pointed out that "entrepreneurs of course may be inventors just as they may be capitalists, they are inventors not by nature of their function but by coincidence and vice versa." This means that
ABSTRACT Investigations were conducted to determine the geo-electrical properties, aquifer potent... more ABSTRACT Investigations were conducted to determine the geo-electrical properties, aquifer potential and quality of groundwater samples of the Ajali Sandstone Formation at Ninth mile area, Nigeria. Results reveal that the formation has 4 to 6 geo-electric layers, with the 5th recording hydraulic conductivity, transmissivity and transverse resistance values that suggested a general high yield to boreholes. The aquifer longitudinal conductance analysis indicates poor aquifer protective capacity, thus, high risk of contamination by effluents from the heavy industries within the area. Qualitative analysis shows major ionic concentrations, in the order: Na+>K+>Ca2+>Mg2+>Fe2+>HCO3->Cl->SO42-> NO3-, that satisfy all permissible limits for drinking purpose. All tested samples have heavy metals, except Pb2+, also fall within acceptable limits. High amount of Pb2+ originated most probably from improper disposal of ‘leaded’ petroleum products or leaching of lead from metal casing used in the well development. That the water samples satisfied almost all limits for drinking purpose despite the poor aquifer protective capacity and high industrialization may imply that the wastewater received fairly adequate treatments before discharge. Caution should; however, be applied in dealing with factors that give rise to lead contamination and in the water usage.
Characterization of red onion skin tannin (ROST) was done using FTIR and UV/visible spectrophotom... more Characterization of red onion skin tannin (ROST) was done using FTIR and UV/visible spectrophotometric techniques, revealing ROST to be made up of mixed (hydrolysable and condensed) tannins. ROST has been found to be an effective corrosion inhibitor of aluminium in hydrochloric acid solutions using gravimetric, thermometric, and UV/visible spectrophotometric techniques. Proposed kinetic model reveals complex reaction mechanism (parallel reactions) for aluminium corrosion inhibition by ROST. ROST adsorption on aluminium followed Langmuir isotherm in 0.1M and Fruendlich isotherm in 0.5M HCl and 2.0M HCl at 303 Kelvin. Physical adsorption (physisorption) of ROST on aluminium has been proposed.
Batch adsorption has been used to study the adsorption performance of coal based activated carbon... more Batch adsorption has been used to study the adsorption performance of coal based activated carbon (COBAC) in a fibre-cement effluent (FCE) at room temperature and pH of 12. This paper demonstrates the use of analysis of variance (ANOVA) and Fisher's least significant difference statistics in the determination of the adsorption performance of COBAC at varying time and various dosages. Increasing COBAC dosage and adsorption time respectively, had high significant differences on the adsorption performance of COBAC. In addition, time/dosage interactions had significant difference on COBAC adsorption performance. Adsorption dynamics studies show that 'animekus' expression for pseudo second order kinetic model gave the best predicted adsorption capacity values and as such, favours chemisorption mechanism. Thermodynamic studies reveal effective adsorption of suspended solids onto COBAC. Equilibrium studies revealed that adsorption data of suspended particles onto COBAC followed Langmuir pattern reaffirming chemisorption adsorption mechanism.
Adsorption of anthocleista djalonensis leaf extract on aluminum in hydrochloric acid solution was... more Adsorption of anthocleista djalonensis leaf extract on aluminum in hydrochloric acid solution was studied at 30°C and 60°C using gravimetric technique. Increasing the concentration (v/v %) of anthocleista djalonensis leaf extract was observed to increase its corrosion inhibition efficiency. Temperature studies revealed an increase in inhibition efficiency with rise in temperature. Comparative analysis of kinetic and thermodynamic parameters revealed effective inhibition. This paper demonstrates the use of two statistical approaches – Analysis of variance (ANOVA) and Duncan multiple range test, in the determination of the performance of various linearised Langmuir equations.
ABSTRACT Anthocleista djalonensis leaf extract –a renewable, easily available and non-toxic agric... more ABSTRACT Anthocleista djalonensis leaf extract –a renewable, easily available and non-toxic agricultural byproduct of West African origin, has been demonstrated to have good corrosion inhibition property.The corrosion inhibition of aluminium in HCl using leaf extract of Anthocleista djalonensis is reported at 30˚C-60˚C using weight loss and thermometric techniques. Leaf extract of Anthocleista djalonensis acted as inhibitor for aluminium in HCl and the inhibition efficiency (%I) increased with concentration of leaf extract of Anthocleista djalonensis. The corrosion inhibition property was by adsorption of the phytochemicals – sitosterol, stigmasterol, sweroside or djalonenoside, 3-oxo- Δ -4, 5-sitosterone and ursolic acid, on the aluminium. Temperature studies revealed a decrease in inhibition efficiency with rise in temperature. The adsorption of the leaf extract of Anthocleista djalonensis on aluminum in HCl solution obeyed the Langmuir, Temkin, Freundlich and EL-Awady adsorption isotherms
Cashew nut testa tannin [CASTAN] has been found to inhibit the corrosion of aluminium in hydrochl... more Cashew nut testa tannin [CASTAN] has been found to inhibit the corrosion of aluminium in hydrochloric acid solutions using gravimetric, thermometric and UV/visible spectrophotometric techniques. CASTAN inhibition was by adsorption on aluminium following Temkin isotherm in 0.1 M HCl and Langmuir isotherm in 0.5 M and 2.0 M HCl at 303 Kelvin. Physical adsorption on aluminium has been proposed in studied HCl solutions; therefore, CASTAN is a cathodic inhibitor. Earlier reports [1] showed CASTAN to contain quercetin, azaleatin, catechin, epicatechin, cyanidin and delphinidin. However, UV/visible spectrophotometric analysis of CASTAN in ethanol reveals quercetin as its major component. This work therefore investigated the correlation between computed molecular parameters and inhibitive properties of CASTAN and adsorption sites on its components. Calculated quantum chemical parameters namely: E HOMO (highest occupied molecular orbital energy), E LUMO (lowest unoccupied molecular orbital energy), energy gap (∆E) and dipole moment (µ) suggest that CASTAN is a soft inhibitor and it's components inhibited aluminium corrosion in protonated forms. Calculated Mulliken charges implicated some electron rich sites, namely: the aromatic and conjugated C=C, C=O and O-H as adsorption sites on the inhibitor molecules. Proposed kinetic model reveals complex reaction mechanism, parallel reactions, for aluminium corrosion inhibition by CASTAN.
Investigation of exudates of Eucalyptus citriodora as corrosion inhibitor of aluminium and mild s... more Investigation of exudates of Eucalyptus citriodora as corrosion inhibitor of aluminium and mild steel was carried out using the weight loss technique. In various concentrations of hydrochloric acid solutions, the presence of exudates of Eucalyptus citriodora inhibited aluminium and mild steel corrosions. Phenomenon of physical adsorption is proposed for the inhibitions and the processes followed the Temkin adsorption isotherm. Free energies of adsorption indicate spontaneous adsorption. The equilibrium constants of the adsorption processes predict better corrosion inhibition of aluminium than mild steel. Lateral interaction from Temkin plots; suggest repulsive lateral interactions between inhibitor species.
Adsorption of metal ions and dyes from water by cashew nut testa tannin resin (CATAR) was studied... more Adsorption of metal ions and dyes from water by cashew nut testa tannin resin (CATAR) was studied and the effects of temperature, initial pH, initial concentration and time were investigated. Scanning electron microscopy (SEM) and infrared spectroscopy (FTIR) reveal effective adsorption processes. Kinetic studies show that CATAR adsorption is complex and thermodynamic parameters calculated reveal spontaneous and endothermic adsorption of studied pollutants onto CATAR. The use of CATAR as an alternative adsorbent is proposed considering that of simulated wastewaters gave excellent removal performances of 94.0% (Cd ions), 99.4% (Cu ions) and 97.1% (Pb ions) at pH of 6 and 303 K using amount of CATAR. Removal performances obtained for simulated dye wastewaters using CATAR at similar conditions for removal of metal ions gave 71.1%, 79.2% and 86.6%, respectively for crystal violet, methylene blue and malachite green.
Metal deterioration over time is a process known as corrosion, an electrochemical process, which ... more Metal deterioration over time is a process known as corrosion, an electrochemical process, which can occur by surface chemical actions on metals by its environment. Metal corrosion have great economic, security, and environmental consequences, and its control is a major research area in corrosion science. Amongst the different corrosion protecting approaches, the use of corrosion inhibitors and protective coatings have attracted enormous research interest in this area of scholasticism. This has necessitated the computational and electrochemical investigations of aluminium corrosion inhibitive potentials of some compounds in 1M HCl. Metal free (5_H2), ClGa(III) (5_Ga) and Co(II) (5_Co) tetrakis(4-acetamidophenoxy)phthalocyanines as well as Co(II) 2,9,16-tris(4-(tert-butyl)phenoxy)-23-(pyridin-4-yloxy)phthalocyanine (6) and Co(II) 2,9,16,24-tetrakis(4-(tert-butyl)phenoxy)phthalocyanine (7) were synthesized for the first time and studied for corrosion inhibition. The reported ClGa(III)...
Abstract N -(2-chloroethyl)morpholine-4-carboxamide (NCMC), N -(2-chloroethyl)tiomorpholine-4-car... more Abstract N -(2-chloroethyl)morpholine-4-carboxamide (NCMC), N -(2-chloroethyl)tiomorpholine-4-carboxamide (NCTC) and N , N -bis(2-chloroethyl)piperazine-1,4-dicarboxamide (NCPD) were studied as corrosion inhibitors for mild steel using atomic absorption spectroscopy (AAS) and gravimetry and thermometry. Results obtained from the three techniques are similar and reveal that the compounds inhibit mild steel corrosion. The inhibition efficiencies increased from 35.6% to 74.9% (NCMC), 44.5% to 82.4% (NCPD) and 52.6% to 90.1% (NCTC) at 30 °C when the inhibitor concentrations increased from 10 μM to 50 μM. The maximum inhibition efficiency values (at 50 μM) decreased to 46.6%, 58.1% and 61.2% for NCMC, NCPD and NCTC respectively, when the temperature was raised to 50 °C. The decrease in inhibition efficiency with increase in temperature suggested predominant physisorption mechanism in metal/inhibitor interactions. The formation of protective films of NCMC, NCPD and NCTC molecules on mild steel surface were confirmed by FTIR and XRD. The order of inhibitive strengths of the molecules is NCTC > NCPD > NCMC. Quantum chemical calculations revealed the prospective sites through which the molecules can interact with mild steel surface and some quantum chemically derived parameters were used to corroborate experimental.
Human African trypanosomiasis, also known as sleeping sickness, is caused by the single-celled ki... more Human African trypanosomiasis, also known as sleeping sickness, is caused by the single-celled kinetoplastid parasite Trypanosoma brucei transmitted to humans by infected tsetse flies. The disease threatens millions of people. Currently available treatment options are faced with some important challenges. In this work, a total of eighty-seven (87) morpholine derivatives were evaluated for drug-likeness based on Lipinski’s rule of five and their ability to inhibit the activities of trypanosomal triosephosphate isomerase was assessed by molecular docking and calculation of free energy of binding. Analysis of the results revealed that 97.7 % of the dataset complied with Lipinski’s criteria for a molecule to be orally bioavailable. Also, 50.0 % of the studied compounds had a good total polar surface area profile, a parameter which is of great importance for the treatment of stage two Trypanosoma infections. Docking studies showed that all the dataset demonstrated affinity for triosephosphate isomerase. Moreover, six morpholines scored higher than the co-crystallized inhibitor of triosephosphate isomerase (2-phosphoglycerate). These derivatives inhibited the activity of triosephosphate isomerase by making significant interactions with Glu 167, Val 214, 233, Asn 11, Lys 13, Ser 213, Leu 232, Ile 172, Gly 211, 212, 234, 235 and His 92 in the active site of the protein. Furthermore, besides the acceptable pharmacokinetic profiles of the six morpholines, they also showed inhibitory potencies toward four other validated antitrypanosomal drug targets. In view of the foregoing findings, we propose that the six morpholine derivatives be given worthwhile attention to develop them into novel trypanocides.
Journal of Environmental Chemical Engineering, 2016
Beyond systematic entrepreneurship: The role of intuition in experience innovation In this paper ... more Beyond systematic entrepreneurship: The role of intuition in experience innovation In this paper we start from the conception of experience innovation as originally proposed by Prahalad and Ramaswamy (2003) since this approach seems to contradict the assumption that entrepreneurship is a systematic behaviour based on concept and theory rather than a personality trait based on intuition (see Drucker, 2006). We attend to the questions: What is the role of creative intuition in experience innovation? and How should be entrepreneurship studied in future? In economics, experiences are distinct economic values in the form of personally engaging events that remain memorable for the customers (Pine II & Gilmore, 2000) but they function according to a quite different set of internally consistent assumptions of value creation compared to services and products (Prahalad, 2004). Hence, value is created at the point of exchange, and services and products are merely regarded as carriers of experiences (see Prahalad, 2004: 173). Innovation remains a consistent factor in this economic shift from services to experiences, but here innovation is focused on experiences rather than on products or services. Experience innovation aims at nudging the co-creation of experience spaces in which "personalized, evolvable experiences are the goal, and products and services evolve as a means to that end" (Prahalad & Ramaswamy, 2003: 18). Traditionally entrepreneurship and innovation go hand in hand because the latter is believed to have its source in the Unternehmergeist (entrepreneurial spirit). However, Schumpeter (1911: 88-89) pointed out that "entrepreneurs of course may be inventors just as they may be capitalists, they are inventors not by nature of their function but by coincidence and vice versa." This means that
ABSTRACT Investigations were conducted to determine the geo-electrical properties, aquifer potent... more ABSTRACT Investigations were conducted to determine the geo-electrical properties, aquifer potential and quality of groundwater samples of the Ajali Sandstone Formation at Ninth mile area, Nigeria. Results reveal that the formation has 4 to 6 geo-electric layers, with the 5th recording hydraulic conductivity, transmissivity and transverse resistance values that suggested a general high yield to boreholes. The aquifer longitudinal conductance analysis indicates poor aquifer protective capacity, thus, high risk of contamination by effluents from the heavy industries within the area. Qualitative analysis shows major ionic concentrations, in the order: Na+>K+>Ca2+>Mg2+>Fe2+>HCO3->Cl->SO42-> NO3-, that satisfy all permissible limits for drinking purpose. All tested samples have heavy metals, except Pb2+, also fall within acceptable limits. High amount of Pb2+ originated most probably from improper disposal of ‘leaded’ petroleum products or leaching of lead from metal casing used in the well development. That the water samples satisfied almost all limits for drinking purpose despite the poor aquifer protective capacity and high industrialization may imply that the wastewater received fairly adequate treatments before discharge. Caution should; however, be applied in dealing with factors that give rise to lead contamination and in the water usage.
Characterization of red onion skin tannin (ROST) was done using FTIR and UV/visible spectrophotom... more Characterization of red onion skin tannin (ROST) was done using FTIR and UV/visible spectrophotometric techniques, revealing ROST to be made up of mixed (hydrolysable and condensed) tannins. ROST has been found to be an effective corrosion inhibitor of aluminium in hydrochloric acid solutions using gravimetric, thermometric, and UV/visible spectrophotometric techniques. Proposed kinetic model reveals complex reaction mechanism (parallel reactions) for aluminium corrosion inhibition by ROST. ROST adsorption on aluminium followed Langmuir isotherm in 0.1M and Fruendlich isotherm in 0.5M HCl and 2.0M HCl at 303 Kelvin. Physical adsorption (physisorption) of ROST on aluminium has been proposed.
Batch adsorption has been used to study the adsorption performance of coal based activated carbon... more Batch adsorption has been used to study the adsorption performance of coal based activated carbon (COBAC) in a fibre-cement effluent (FCE) at room temperature and pH of 12. This paper demonstrates the use of analysis of variance (ANOVA) and Fisher's least significant difference statistics in the determination of the adsorption performance of COBAC at varying time and various dosages. Increasing COBAC dosage and adsorption time respectively, had high significant differences on the adsorption performance of COBAC. In addition, time/dosage interactions had significant difference on COBAC adsorption performance. Adsorption dynamics studies show that 'animekus' expression for pseudo second order kinetic model gave the best predicted adsorption capacity values and as such, favours chemisorption mechanism. Thermodynamic studies reveal effective adsorption of suspended solids onto COBAC. Equilibrium studies revealed that adsorption data of suspended particles onto COBAC followed Langmuir pattern reaffirming chemisorption adsorption mechanism.
Adsorption of anthocleista djalonensis leaf extract on aluminum in hydrochloric acid solution was... more Adsorption of anthocleista djalonensis leaf extract on aluminum in hydrochloric acid solution was studied at 30°C and 60°C using gravimetric technique. Increasing the concentration (v/v %) of anthocleista djalonensis leaf extract was observed to increase its corrosion inhibition efficiency. Temperature studies revealed an increase in inhibition efficiency with rise in temperature. Comparative analysis of kinetic and thermodynamic parameters revealed effective inhibition. This paper demonstrates the use of two statistical approaches – Analysis of variance (ANOVA) and Duncan multiple range test, in the determination of the performance of various linearised Langmuir equations.
ABSTRACT Anthocleista djalonensis leaf extract –a renewable, easily available and non-toxic agric... more ABSTRACT Anthocleista djalonensis leaf extract –a renewable, easily available and non-toxic agricultural byproduct of West African origin, has been demonstrated to have good corrosion inhibition property.The corrosion inhibition of aluminium in HCl using leaf extract of Anthocleista djalonensis is reported at 30˚C-60˚C using weight loss and thermometric techniques. Leaf extract of Anthocleista djalonensis acted as inhibitor for aluminium in HCl and the inhibition efficiency (%I) increased with concentration of leaf extract of Anthocleista djalonensis. The corrosion inhibition property was by adsorption of the phytochemicals – sitosterol, stigmasterol, sweroside or djalonenoside, 3-oxo- Δ -4, 5-sitosterone and ursolic acid, on the aluminium. Temperature studies revealed a decrease in inhibition efficiency with rise in temperature. The adsorption of the leaf extract of Anthocleista djalonensis on aluminum in HCl solution obeyed the Langmuir, Temkin, Freundlich and EL-Awady adsorption isotherms
Cashew nut testa tannin [CASTAN] has been found to inhibit the corrosion of aluminium in hydrochl... more Cashew nut testa tannin [CASTAN] has been found to inhibit the corrosion of aluminium in hydrochloric acid solutions using gravimetric, thermometric and UV/visible spectrophotometric techniques. CASTAN inhibition was by adsorption on aluminium following Temkin isotherm in 0.1 M HCl and Langmuir isotherm in 0.5 M and 2.0 M HCl at 303 Kelvin. Physical adsorption on aluminium has been proposed in studied HCl solutions; therefore, CASTAN is a cathodic inhibitor. Earlier reports [1] showed CASTAN to contain quercetin, azaleatin, catechin, epicatechin, cyanidin and delphinidin. However, UV/visible spectrophotometric analysis of CASTAN in ethanol reveals quercetin as its major component. This work therefore investigated the correlation between computed molecular parameters and inhibitive properties of CASTAN and adsorption sites on its components. Calculated quantum chemical parameters namely: E HOMO (highest occupied molecular orbital energy), E LUMO (lowest unoccupied molecular orbital energy), energy gap (∆E) and dipole moment (µ) suggest that CASTAN is a soft inhibitor and it's components inhibited aluminium corrosion in protonated forms. Calculated Mulliken charges implicated some electron rich sites, namely: the aromatic and conjugated C=C, C=O and O-H as adsorption sites on the inhibitor molecules. Proposed kinetic model reveals complex reaction mechanism, parallel reactions, for aluminium corrosion inhibition by CASTAN.
Investigation of exudates of Eucalyptus citriodora as corrosion inhibitor of aluminium and mild s... more Investigation of exudates of Eucalyptus citriodora as corrosion inhibitor of aluminium and mild steel was carried out using the weight loss technique. In various concentrations of hydrochloric acid solutions, the presence of exudates of Eucalyptus citriodora inhibited aluminium and mild steel corrosions. Phenomenon of physical adsorption is proposed for the inhibitions and the processes followed the Temkin adsorption isotherm. Free energies of adsorption indicate spontaneous adsorption. The equilibrium constants of the adsorption processes predict better corrosion inhibition of aluminium than mild steel. Lateral interaction from Temkin plots; suggest repulsive lateral interactions between inhibitor species.
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