The inhibitory potentials of ethanolic extracts and four fractions of the stem bark of Ficus asperifolia – Miq. for the corrosion of mild steel were assessed using weight loss method, Fourier atomic absorption spectroscopy, scanning electron microscopy (SEM). The effects of varying immersion period, concentration of the inhibitors and temperatures for mild steel corrosion in 5 M HCl acid solution were carried out. A detailed kinetic reaction, thermodynamic (Ea, ∆H, ∆S) and adsorption isotherm studies were obtained. The crude extract of F. asperifolia (EFA) has the highest inhibition efficiency of 55%. The inhibitory efficiency of the four fractions of F. asperifolia (EFA) compared with the crude extract was in the order ethyl acetate > n-hexane > butanol > EFA > Aqueous. The inhibition efficiency was found to increase with increase in the extracts concentration but decreased with temperature. Corrosion rate increases with time but decreases with extracts concentration. The kinetic studies of the data followed a first order reaction. Thermodynamic studies revealed that corrosion inhibition may be due to spontaneous mixed adsorption of the plant constituents on the metal surface. Experimental data were fitted to Langmuir, Freundlich and Temkin adsorption isotherms. The plant investigated showed a good potential for green corrosion inhibitors. Investigation of phytochemical constituents showed that the extracts contain alkaloids, flavonoids, saponins, tannins anthraquinones and reducing sugars. Key words: Inhibitory efficiency, corrosion rate, adsorption isotherm.
{"title":"Assessment of anti-corrosion potentials of extract of Ficus asperifolia -Miq (Moraceae) on mild steel in acidic medium","authors":"Oluniyi O. Fadare, A. Okoronkwo, E. Olasehinde","doi":"10.5897/AJPAC2015.0651","DOIUrl":"https://doi.org/10.5897/AJPAC2015.0651","url":null,"abstract":"The inhibitory potentials of ethanolic extracts and four fractions of the stem bark of Ficus asperifolia – Miq. for the corrosion of mild steel were assessed using weight loss method, Fourier atomic absorption spectroscopy, scanning electron microscopy (SEM). The effects of varying immersion period, concentration of the inhibitors and temperatures for mild steel corrosion in 5 M HCl acid solution were carried out. A detailed kinetic reaction, thermodynamic (Ea, ∆H, ∆S) and adsorption isotherm studies were obtained. The crude extract of F. asperifolia (EFA) has the highest inhibition efficiency of 55%. The inhibitory efficiency of the four fractions of F. asperifolia (EFA) compared with the crude extract was in the order ethyl acetate > n-hexane > butanol > EFA > Aqueous. The inhibition efficiency was found to increase with increase in the extracts concentration but decreased with temperature. Corrosion rate increases with time but decreases with extracts concentration. The kinetic studies of the data followed a first order reaction. Thermodynamic studies revealed that corrosion inhibition may be due to spontaneous mixed adsorption of the plant constituents on the metal surface. Experimental data were fitted to Langmuir, Freundlich and Temkin adsorption isotherms. The plant investigated showed a good potential for green corrosion inhibitors. Investigation of phytochemical constituents showed that the extracts contain alkaloids, flavonoids, saponins, tannins anthraquinones and reducing sugars. \u0000 \u0000 \u0000 \u0000 Key words: Inhibitory efficiency, corrosion rate, adsorption isotherm.","PeriodicalId":7556,"journal":{"name":"African Journal of Pure and Applied Chemistry","volume":"195 1","pages":"8-22"},"PeriodicalIF":0.0,"publicationDate":"2016-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83462706","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We have investigated the green synthesis and antimicrobial activity of silver nanoparticles using Garcinia kola. Aqueous extract of G. kola was used to reduce AgNO3 solution to obtain black nanocrystal of silver nanoparticles. Antimicrobial activity of the silver nanoparticles was tested against Escherichia coli, Klebsiella pneumonia, Bacillus subtilis, Staphylococcus aureus, Aspergillus niger, Rhizopus stolonifer and Candida albican. The synthesized silver nanoparticles was characterized using UV-vis spectroscopy, X-ray diffraction (XRD), Transmission electron microscopy (TEM), and Fourier transform infrared (FTIR) spectroscopy. UV-visible exhibits prominently the characteristic surface plasmon resonance at around 427 nm. A remarkable particle growth onset of 10 min was observed while the reaction ended within 30 min. The XRD analysis shows that the synthesized silver nanoparticles are crystalline in nature and well-dispersed silver nanoparticles with an approximate size of 10.4 nm were observed on TEM. The synthesized silver was found to possess good antimicrobial activity against all the tested microbes. The application of the green synthesized nanoparticles can be used in many fields such as foods, beverages, cosmetics and medicine. Key words: Silver, nanoparticles, green synthesis, Garcinia kola seed extract, transmission electron microscopy, antimicrobial activity.
{"title":"Biosynthesis of silver nanoparticles using Garcinia kola and its antimicrobial potential","authors":"Labulo Ayomide Hassan, Adesuji Temitope Elijah, Oseghale Charles Ojiefoh, Omojola Joseph, Bodede Olusola. Sunday, Dare Enock Olugbenga, Akinsiku Abimbola Anuoluwapo","doi":"10.5897/AJPAC2015.0650","DOIUrl":"https://doi.org/10.5897/AJPAC2015.0650","url":null,"abstract":"We have investigated the green synthesis and antimicrobial activity of silver nanoparticles using Garcinia kola. Aqueous extract of G. kola was used to reduce AgNO3 solution to obtain black nanocrystal of silver nanoparticles. Antimicrobial activity of the silver nanoparticles was tested against Escherichia coli, Klebsiella pneumonia, Bacillus subtilis, Staphylococcus aureus, Aspergillus niger, Rhizopus stolonifer and Candida albican. The synthesized silver nanoparticles was characterized using UV-vis spectroscopy, X-ray diffraction (XRD), Transmission electron microscopy (TEM), and Fourier transform infrared (FTIR) spectroscopy. UV-visible exhibits prominently the characteristic surface plasmon resonance at around 427 nm. A remarkable particle growth onset of 10 min was observed while the reaction ended within 30 min. The XRD analysis shows that the synthesized silver nanoparticles are crystalline in nature and well-dispersed silver nanoparticles with an approximate size of 10.4 nm were observed on TEM. The synthesized silver was found to possess good antimicrobial activity against all the tested microbes. The application of the green synthesized nanoparticles can be used in many fields such as foods, beverages, cosmetics and medicine. \u0000 \u0000 \u0000 \u0000 Key words: Silver, nanoparticles, green synthesis, Garcinia kola seed extract, transmission electron microscopy, antimicrobial activity.","PeriodicalId":7556,"journal":{"name":"African Journal of Pure and Applied Chemistry","volume":"44 1","pages":"1-7"},"PeriodicalIF":0.0,"publicationDate":"2016-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89596300","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nurudeen Awokoya Kehinde, Tshentu Zenixole, T. Nelson
A nickel vanadyl molecularly imprinted nanofiber (NVMIN) was developed by the electrospinning technique, employing polyethylene terephthalate (PET) and linear polyethylenimine (L-PEI) as the matrix polymers, nickel tetraphenylporphyrin (NTPP) and vanadyl tetraphenylporphyrin (VTPP) as the mixed-template molecules. The fabricated NVMIN was evaluated as a sorbent for the removal of NTPP and VTPP from organic media. The effects of trifluoroacetic acid (TFA), dichloromethane (DCM), dimethyl sulphoxide (DMSO), pentane (PEN) on electro-spinnability of the PET/L-PEI solutions and the morphological appearance of the PET/L-PEI fibers were investigated qualitatively by means of a scanning electron microscope (SEM). Electrospinning of 14 to 30% w/v PET/L-PEI solutions in TFA produced beaded and smooth fibers, depending on the concentration range. The addition of DCM and PEN as modifiers helped improve the electrospinnability, with PEN being the best, while the addition of DMSO made the solutions not spinnable. The results indicated that the NVMIN showed higher affinity (99% higher) for NTPP than the non-imprinted nanofiber (NIN) indicating that the NVMIN contained a lot of specific binding sites. It was determined that the NVMIN exhibited the same selectivity specialism for both NTPP and VTPP. However, the interaction strength was strongly dependant on the type of solvent, where the strongest interaction was achieved in chloroform. In addition, the thermodynamic parameters calculated from the adsorption data suggested that the adsorption of NTPP onto NVMIN was a spontaneous and exothermic process. Key words: Electrospinning, mixed-templates, adsorption, demetallation, solvents.
{"title":"Fabrication and evaluation of multiple template cross-linked molecularly imprinted electro spun nanofibers for selective extraction of nickel and vanadyl tetraphenylporphyrin from organic media","authors":"Nurudeen Awokoya Kehinde, Tshentu Zenixole, T. Nelson","doi":"10.5897/AJPAC2015.0648","DOIUrl":"https://doi.org/10.5897/AJPAC2015.0648","url":null,"abstract":"A nickel vanadyl molecularly imprinted nanofiber (NVMIN) was developed by the electrospinning technique, employing polyethylene terephthalate (PET) and linear polyethylenimine (L-PEI) as the matrix polymers, nickel tetraphenylporphyrin (NTPP) and vanadyl tetraphenylporphyrin (VTPP) as the mixed-template molecules. The fabricated NVMIN was evaluated as a sorbent for the removal of NTPP and VTPP from organic media. The effects of trifluoroacetic acid (TFA), dichloromethane (DCM), dimethyl sulphoxide (DMSO), pentane (PEN) on electro-spinnability of the PET/L-PEI solutions and the morphological appearance of the PET/L-PEI fibers were investigated qualitatively by means of a scanning electron microscope (SEM). Electrospinning of 14 to 30% w/v PET/L-PEI solutions in TFA produced beaded and smooth fibers, depending on the concentration range. The addition of DCM and PEN as modifiers helped improve the electrospinnability, with PEN being the best, while the addition of DMSO made the solutions not spinnable. The results indicated that the NVMIN showed higher affinity (99% higher) for NTPP than the non-imprinted nanofiber (NIN) indicating that the NVMIN contained a lot of specific binding sites. It was determined that the NVMIN exhibited the same selectivity specialism for both NTPP and VTPP. However, the interaction strength was strongly dependant on the type of solvent, where the strongest interaction was achieved in chloroform. In addition, the thermodynamic parameters calculated from the adsorption data suggested that the adsorption of NTPP onto NVMIN was a spontaneous and exothermic process. \u0000 \u0000 Key words: Electrospinning, mixed-templates, adsorption, demetallation, solvents.","PeriodicalId":7556,"journal":{"name":"African Journal of Pure and Applied Chemistry","volume":"30 1","pages":"223-239"},"PeriodicalIF":0.0,"publicationDate":"2015-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88032680","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The study and application of health risk assessment techniques are crucial in order to understand the risk of exposure to heavy metals and other harmful pollutants. It entails evaluating the risks of exposure at various concentrations and with reference to certain standard values approved by World Health Organization (WHO) and United States Environmental Protection Agency (USEPA). Investigation of water contamination with heavy metals has become the prime focus of environmental scientists in recent years. Effluent discharges into aquatic system affect living organisms within the receiving environment. The concentrations of these metals were mostly assessed at 50th, 75th and 95th percentile and various exposure evaluated. This review covers studies in water, air, soil and fish samples. Air risks assessment was not given the needed attention and children were more susceptible to the hazard than adult, especially lead toxicity, resulting in health complications. Heavy metals bio accumulates over time, and lethal upon exposure at low concentrations. This review will assist risk managers to minimize the exposure at optimum level as well as for the government to formulate policies in safe guarding the health of population. Key words: Health risk assessment, pollution, heavy metals, water, air, soil.
{"title":"Health risk assessment of heavy metals in water, air, soil and fish","authors":"Isa Baba Koki, A. Bayero, A. Umar, S. Yusuf","doi":"10.5897/AJPAC2015.0654","DOIUrl":"https://doi.org/10.5897/AJPAC2015.0654","url":null,"abstract":"The study and application of health risk assessment techniques are crucial in order to understand the risk of exposure to heavy metals and other harmful pollutants. It entails evaluating the risks of exposure at various concentrations and with reference to certain standard values approved by World Health Organization (WHO) and United States Environmental Protection Agency (USEPA). Investigation of water contamination with heavy metals has become the prime focus of environmental scientists in recent years. Effluent discharges into aquatic system affect living organisms within the receiving environment. The concentrations of these metals were mostly assessed at 50th, 75th and 95th percentile and various exposure evaluated. This review covers studies in water, air, soil and fish samples. Air risks assessment was not given the needed attention and children were more susceptible to the hazard than adult, especially lead toxicity, resulting in health complications. Heavy metals bio accumulates over time, and lethal upon exposure at low concentrations. This review will assist risk managers to minimize the exposure at optimum level as well as for the government to formulate policies in safe guarding the health of population. \u0000 \u0000 Key words: Health risk assessment, pollution, heavy metals, water, air, soil.","PeriodicalId":7556,"journal":{"name":"African Journal of Pure and Applied Chemistry","volume":"25 1","pages":"204-210"},"PeriodicalIF":0.0,"publicationDate":"2015-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78635768","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
New nanocomposite MnO2/Al2O3/Fe2O3 photocatalyst was successfully synthesized by sol-gel method using metal salts as precursors in the presence of acid catalyst. The as-synthesized samples were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR), atomic absorption spectroscopy (AAS) and UV-Vis diffuse reflectance spectroscopy. Elemental analyses of the as-synthesized samples were similar to those expected from the initial concentrations of the solutions used during synthesis. The x-ray diffraction pattern indicated that all as-synthesized samples had a crystal size with a rhombohedral structure and finest particle size of the catalyst (20.096 nm) was obtained at 400°C calcination temperature. The band gap energy of the MnO2/Al2O3/Fe2O3 photocatalyst was calculated to be 1.97 eV and indicated that the as-synthesize sample had high photoabsorption property in the visible light region. Fourier transform infrared spectra confirmed the presence of hydroxyl group and Fe-O bond vibration in the catalyst. Experimental result of the MnO2/Al2O3/Fe2O3 photocatalyst calcined at 400°C in 180 min (the molar ratio of 10 wt% Mn/15 wt% Al/75 wt% Fe) exhibited high photocatalytic activity of 92.89% under visible light irradiation. This may be due to the coupling effect of semiconductors, small particle size of catalyst and low electron-hole pair recombination on the surface of the catalyst. The pseudo-first-order rate constants of MG dye degradation in the presence of the catalyst were calculated as 4 × 10-4, 6.56 × 10-3 and 1.0 × 10-2 min-1 under no light irradiation, UV and visible light irradiation, respectively. Key words: Malachite green, nanoparticles, photocatalysis, sol-gel synthesis, ternaryoxides.
{"title":"Synthesis, characterization and photocatalytic activity of MnO2/Al2O3/Fe2O3 nanocomposite for degradation of malachite green","authors":"Haile Hasana Logita, Abi M. Tadesse, T. Kebede","doi":"10.5897/AJPAC2015.0656","DOIUrl":"https://doi.org/10.5897/AJPAC2015.0656","url":null,"abstract":"New nanocomposite MnO2/Al2O3/Fe2O3 photocatalyst was successfully synthesized by sol-gel method using metal salts as precursors in the presence of acid catalyst. The as-synthesized samples were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR), atomic absorption spectroscopy (AAS) and UV-Vis diffuse reflectance spectroscopy. Elemental analyses of the as-synthesized samples were similar to those expected from the initial concentrations of the solutions used during synthesis. The x-ray diffraction pattern indicated that all as-synthesized samples had a crystal size with a rhombohedral structure and finest particle size of the catalyst (20.096 nm) was obtained at 400°C calcination temperature. The band gap energy of the MnO2/Al2O3/Fe2O3 photocatalyst was calculated to be 1.97 eV and indicated that the as-synthesize sample had high photoabsorption property in the visible light region. Fourier transform infrared spectra confirmed the presence of hydroxyl group and Fe-O bond vibration in the catalyst. Experimental result of the MnO2/Al2O3/Fe2O3 photocatalyst calcined at 400°C in 180 min (the molar ratio of 10 wt% Mn/15 wt% Al/75 wt% Fe) exhibited high photocatalytic activity of 92.89% under visible light irradiation. This may be due to the coupling effect of semiconductors, small particle size of catalyst and low electron-hole pair recombination on the surface of the catalyst. The pseudo-first-order rate constants of MG dye degradation in the presence of the catalyst were calculated as 4 × 10-4, 6.56 × 10-3 and 1.0 × 10-2 min-1 under no light irradiation, UV and visible light irradiation, respectively. \u0000 \u0000 Key words: Malachite green, nanoparticles, photocatalysis, sol-gel synthesis, ternaryoxides.","PeriodicalId":7556,"journal":{"name":"African Journal of Pure and Applied Chemistry","volume":"6 1","pages":"211-222"},"PeriodicalIF":0.0,"publicationDate":"2015-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83861725","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A small library of benzimidazoles with a range of side-chain substituents have been synthesized through the condensation reaction of o-phenylenediamine derivatives and several other commercially available materials. The reactions were catalyzed by either 4M HCl or 1,3-dibromo-5,5-dimethylhydantoin (DBDMH). The compounds synthesized using DBDMH as the catalyst required a shorter reaction time, the yield was higher and the workup procedure was not as tedious as those produced using 4M HCl as the catalyst. The structural elucidations of synthesized compounds have been confirmed through spectroscopic analysis. 13C NMR analysis of some of the synthesized compounds showed that the appearance of carbon signals in the NMR spectrum is affected by the nature of the NMR solvent and temperature.The exchange-induced broadening of the 13C NMR signal was probably facilitated by the intermolecular proton exchange between the NH of the benzimidazole and the H2O present in the DMSO-d6 solvent. Key words: 1,3-dibromo-5,5-dimethylhydantoin, benzimidazole, solvent-effect, structure elucidation, synthetic method.
{"title":"Comparative study of 1,3-dibromo-5,5-dimethylhydantoin assisted and conventional synthesis of benzimidazole derivatives and the solvent effects on spectroscopic properties","authors":"A. S. Peter","doi":"10.5897/AJPAC2015.0655","DOIUrl":"https://doi.org/10.5897/AJPAC2015.0655","url":null,"abstract":"A small library of benzimidazoles with a range of side-chain substituents have been synthesized through the condensation reaction of o-phenylenediamine derivatives and several other commercially available materials. The reactions were catalyzed by either 4M HCl or 1,3-dibromo-5,5-dimethylhydantoin (DBDMH). The compounds synthesized using DBDMH as the catalyst required a shorter reaction time, the yield was higher and the workup procedure was not as tedious as those produced using 4M HCl as the catalyst. The structural elucidations of synthesized compounds have been confirmed through spectroscopic analysis. 13C NMR analysis of some of the synthesized compounds showed that the appearance of carbon signals in the NMR spectrum is affected by the nature of the NMR solvent and temperature.The exchange-induced broadening of the 13C NMR signal was probably facilitated by the intermolecular proton exchange between the NH of the benzimidazole and the H2O present in the DMSO-d6 solvent. \u0000 \u0000 \u0000 \u0000 Key words: 1,3-dibromo-5,5-dimethylhydantoin, benzimidazole, solvent-effect, structure elucidation, synthetic method.","PeriodicalId":7556,"journal":{"name":"African Journal of Pure and Applied Chemistry","volume":"1996 1","pages":"197-203"},"PeriodicalIF":0.0,"publicationDate":"2015-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88143529","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The extract of Terminalia macroptera Guill. & Perr. has been used in the management of pile and other ailments across West Africa. This has necessitated the evaluation of the toxicity of this plant in Sub-chronic and acute administration as well as heavy metal analysis. The root of T. macroptera was extracted with ethanol and analyzed for the presence of phytochemicals. The powdered root was digested and analyzed for presence of Cd, Cr, Pb, Ni and Zn using spectrophotometric technique. The sub-acute toxicity on some liver parameters was evaluated following the administration at doses of 1.5, 1.0 and 0.5 g/kg respectively. The phytochemical screening of the extract revealed the presence of alkaloids, flavonoids, steroids, glycoside, resins and saponin. No death of a single animal was recorded after the acute toxicity study. The effect of sub-chronically administered extract was P< 0.05 of ALT, AST and ALP at different doses when compared to the control. The quantity of metal detected was; Cd (0.0830 ppm), Cr (0.3516 ppm), Pb (0.8809 ppm), Ni (0.6438 ppm) and Zn (0.7340 ppm), which are all within the normal range (1 ppm) as recommended by the Federal Ministry of Environment, Nigeria. Key words: Acute toxicity Heavy metals phytochemicals Terminalia macroptera Guill. & Perr., Sub-chronic toxicity.
{"title":"Toxicity study of ethanol root extract of Terminalia macroptera Guill. Perr. (Combretaceae) and assessment of some heavy metals","authors":"Yakubu Y, A. O, M Wudil A, Ladan Z","doi":"10.5897/AJPAC2015.0647","DOIUrl":"https://doi.org/10.5897/AJPAC2015.0647","url":null,"abstract":"The extract of Terminalia macroptera Guill. & Perr. has been used in the management of pile and other ailments across West Africa. This has necessitated the evaluation of the toxicity of this plant in Sub-chronic and acute administration as well as heavy metal analysis. The root of T. macroptera was extracted with ethanol and analyzed for the presence of phytochemicals. The powdered root was digested and analyzed for presence of Cd, Cr, Pb, Ni and Zn using spectrophotometric technique. The sub-acute toxicity on some liver parameters was evaluated following the administration at doses of 1.5, 1.0 and 0.5 g/kg respectively. The phytochemical screening of the extract revealed the presence of alkaloids, flavonoids, steroids, glycoside, resins and saponin. No death of a single animal was recorded after the acute toxicity study. The effect of sub-chronically administered extract was P< 0.05 of ALT, AST and ALP at different doses when compared to the control. The quantity of metal detected was; Cd (0.0830 ppm), Cr (0.3516 ppm), Pb (0.8809 ppm), Ni (0.6438 ppm) and Zn (0.7340 ppm), which are all within the normal range (1 ppm) as recommended by the Federal Ministry of Environment, Nigeria. \u0000 \u0000 \u0000 \u0000 Key words: Acute toxicity Heavy metals phytochemicals Terminalia macroptera Guill. & Perr., Sub-chronic toxicity.","PeriodicalId":7556,"journal":{"name":"African Journal of Pure and Applied Chemistry","volume":"59 1","pages":"193-196"},"PeriodicalIF":0.0,"publicationDate":"2015-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84626726","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Z. B. Gemechu, T. Kebede, Ephrem G. Demissie, Girma W. Woyessa, S. Kassa
The heterocyclic ligand (L), 3-(2-hydroxy phenyl)-2-iminothiazolidin-4-one, was synthesized by the cyclocondensation of o-hydoxy phenyl chloroacetamide with potassium thiocyanate. The stoichiometries of the title complexes were first determined by spectrophotometric mole ratio method which gave rise to the M:L ratio of 1:4 in case of Zn(II) and Cd(II) and 1:2 in case of Hg(II) ions respectively. Using these predetermined M:L ratios, complexes of the formulas [Zn-L4], [Cd-L4] and [Hg-L2] were prepared accordingly using precursor of the corresponding metal salts with the title ligand in ethanol medium. The synthesized compounds were characterized by elemental analysis, FTIR, 1H and 13CNMR, UV-Vis and conductometric measurement. Stability constants (Ks) of these complexes were investigated by spectrophotometric mole ratio method. The FTIR, 1H NMR and 13C NMR data revealed that the studied ligand function as monodentate ligand interacting through phenolic oxygen as donor with Zn(II) and Cd(II) and as bidentate ligand interacting through phenolic oxygen and nitrogen atom with Hg(II). The synthesized complexes show conductivity values in the range of 122-133 µSmol-1cm2 in DMSO at 298 K which confirms the electrolytic nature of the complexes. The stability constants decreased with increased temperature, confirming that these metal complexes are not stable at higher temperature. Sufficiently large negative values of ΔG of complex confirm the spontaneous formation of the title complexes. Furthermore, it was noted that the spontaneity of the reaction increased with temperature. The stability constant of these complexes follow the sequence Zn(II)>Cd(II)>Hg(II). Therefore, the overall result is complying very well with the Irving-William series of stability constants of metal complexes. Key words: Stability constants, 3-(2-hydroxyphenyl)-2-iminothiazolidin-4-one, Irving-William series, thermodynamic parameters, mole ratio method.
{"title":"Spectrophotometric study on the stability constants and thermodynamic parameters of Zn2+, Cd2+ and Hg2+ complexes with Imino Thiazolidinone","authors":"Z. B. Gemechu, T. Kebede, Ephrem G. Demissie, Girma W. Woyessa, S. Kassa","doi":"10.5897/AJPAC2015.0636","DOIUrl":"https://doi.org/10.5897/AJPAC2015.0636","url":null,"abstract":"The heterocyclic ligand (L), 3-(2-hydroxy phenyl)-2-iminothiazolidin-4-one, was synthesized by the cyclocondensation of o-hydoxy phenyl chloroacetamide with potassium thiocyanate. The stoichiometries of the title complexes were first determined by spectrophotometric mole ratio method which gave rise to the M:L ratio of 1:4 in case of Zn(II) and Cd(II) and 1:2 in case of Hg(II) ions respectively. Using these predetermined M:L ratios, complexes of the formulas [Zn-L4], [Cd-L4] and [Hg-L2] were prepared accordingly using precursor of the corresponding metal salts with the title ligand in ethanol medium. The synthesized compounds were characterized by elemental analysis, FTIR, 1H and 13CNMR, UV-Vis and conductometric measurement. Stability constants (Ks) of these complexes were investigated by spectrophotometric mole ratio method. The FTIR, 1H NMR and 13C NMR data revealed that the studied ligand function as monodentate ligand interacting through phenolic oxygen as donor with Zn(II) and Cd(II) and as bidentate ligand interacting through phenolic oxygen and nitrogen atom with Hg(II). The synthesized complexes show conductivity values in the range of 122-133 µSmol-1cm2 in DMSO at 298 K which confirms the electrolytic nature of the complexes. The stability constants decreased with increased temperature, confirming that these metal complexes are not stable at higher temperature. Sufficiently large negative values of ΔG of complex confirm the spontaneous formation of the title complexes. Furthermore, it was noted that the spontaneity of the reaction increased with temperature. The stability constant of these complexes follow the sequence Zn(II)>Cd(II)>Hg(II). Therefore, the overall result is complying very well with the Irving-William series of stability constants of metal complexes. \u0000 \u0000 \u0000 \u0000 Key words: Stability constants, 3-(2-hydroxyphenyl)-2-iminothiazolidin-4-one, Irving-William series, thermodynamic parameters, mole ratio method.","PeriodicalId":7556,"journal":{"name":"African Journal of Pure and Applied Chemistry","volume":"72 1","pages":"175-183"},"PeriodicalIF":0.0,"publicationDate":"2015-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85826299","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Volatile species (e.g. Na-,K-,Cl-, and S) are released during thermal conversion of coal causing eventual problems such as fouling, slagging and corrosion, especially in gas turbines, on super heaters and in the colder part of heat recovery systems. Thermodynamic study of the released inorganic compounds is supportive before eventually launching experimental work. Therefore, thermodynamic equilibrium was calculated using FactSage 5.2, simulating combustion conditions at elevated pressure (5, 10 and 15 bar) and elevated temperature (1000, 1400 and 1600°C). Their releasing order of various volatile species was estimated by plotting mole fraction of each species at temperature 1000°C and pressure 1 bar. These calculations predict that SO2 is the most stable species for combustion. At all pressure the lowest amount of NaCl and KCl volatilized for LKH and THR lignite char. Evolution of NaCl, KCl and HCl depends on the amount of Cl present in both lignite chars. Key words: Combustion, fact sage, equilibrium calculations, release of volatile species.
{"title":"Thermodynamic analysis of some volatile species at elevated pressure and temperature during combustion of Pakistani Lakhra and Thar lignite chars","authors":"G. Jaffri, S. A. Jaffri, S. A. Jaffri","doi":"10.5897/AJPAC2015.0629","DOIUrl":"https://doi.org/10.5897/AJPAC2015.0629","url":null,"abstract":"Volatile species (e.g. Na-,K-,Cl-, and S) are released during thermal conversion of coal causing eventual problems such as fouling, slagging and corrosion, especially in gas turbines, on super heaters and in the colder part of heat recovery systems. Thermodynamic study of the released inorganic compounds is supportive before eventually launching experimental work. Therefore, thermodynamic equilibrium was calculated using FactSage 5.2, simulating combustion conditions at elevated pressure (5, 10 and 15 bar) and elevated temperature (1000, 1400 and 1600°C). Their releasing order of various volatile species was estimated by plotting mole fraction of each species at temperature 1000°C and pressure 1 bar. These calculations predict that SO2 is the most stable species for combustion. At all pressure the lowest amount of NaCl and KCl volatilized for LKH and THR lignite char. Evolution of NaCl, KCl and HCl depends on the amount of Cl present in both lignite chars. \u0000 \u0000 \u0000 \u0000 Key words: Combustion, fact sage, equilibrium calculations, release of volatile species.","PeriodicalId":7556,"journal":{"name":"African Journal of Pure and Applied Chemistry","volume":"110 1","pages":"184-192"},"PeriodicalIF":0.0,"publicationDate":"2015-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76123358","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
E. Y. Shaba, M. Ndamitso, J. Mathew, M. B. Etsunyakpa, A. Tsado, S. Muhammad
This study investigated the nutritional, anti-nutritional factors, functional properties, mineral and amino acid contents of Phoenix dactylifera L. fruits using standard analytical methods. The results revealed that date palm (P. dactylifera L.) contain some percentage crude protein (1.21 ± 0.02%), crude fat (1.73 ± 0.46%), crude fibre (2.26 ± 0.07%), ash (1.88± 0.03%), moisture contents (1.16± 0.16%), carbohydrate (91.76± 0.06%),and calorific values (1621.50± 0.12 kg/100 g) respectively. The anti-nutrient composition for oxalate, tannins, saponins, alkaloids, cyanide, and flavonoids were 7.57 ± 0.04, 5.25 ± 0.04, 1.89 ± 0.12, 5.20 ± 0.46, 0.80 ± 0.01 and 34.29 ± 3.49% respectively; these result indicated that the sample is free of toxic substance which might cause harm to the body. The non-essential amino acids which give rise to about 62% make the plant more desirable since non-essential amino acid play important role in the body structure of a human. Though, both essential and non-essential amino acid present were there to complement each other. The elemental analysis of the fruit in mg/kg indicated that the fruit contained appreciable levels of K (11105 mg/kg), Na (913 mg/kg), Mg (799 mg/kg) and P (793 mg/kg). This showed that the fruit can serve as good source of minerals. Key words: Nutritional, anti-nutritional, functional, mineral composition.
{"title":"Nutritional and anti-nutritional composition of date palm (Phoenix dactylifera L.) fruits sold in major markets of Minna Niger State, Nigeria","authors":"E. Y. Shaba, M. Ndamitso, J. Mathew, M. B. Etsunyakpa, A. Tsado, S. Muhammad","doi":"10.5897/ajpac2015.0643","DOIUrl":"https://doi.org/10.5897/ajpac2015.0643","url":null,"abstract":"This study investigated the nutritional, anti-nutritional factors, functional properties, mineral and amino acid contents of Phoenix dactylifera L. fruits using standard analytical methods. The results revealed that date palm (P. dactylifera L.) contain some percentage crude protein (1.21 ± 0.02%), crude fat (1.73 ± 0.46%), crude fibre (2.26 ± 0.07%), ash (1.88± 0.03%), moisture contents (1.16± 0.16%), carbohydrate (91.76± 0.06%),and calorific values (1621.50± 0.12 kg/100 g) respectively. The anti-nutrient composition for oxalate, tannins, saponins, alkaloids, cyanide, and flavonoids were 7.57 ± 0.04, 5.25 ± 0.04, 1.89 ± 0.12, 5.20 ± 0.46, 0.80 ± 0.01 and 34.29 ± 3.49% respectively; these result indicated that the sample is free of toxic substance which might cause harm to the body. The non-essential amino acids which give rise to about 62% make the plant more desirable since non-essential amino acid play important role in the body structure of a human. Though, both essential and non-essential amino acid present were there to complement each other. The elemental analysis of the fruit in mg/kg indicated that the fruit contained appreciable levels of K (11105 mg/kg), Na (913 mg/kg), Mg (799 mg/kg) and P (793 mg/kg). This showed that the fruit can serve as good source of minerals. \u0000 \u0000 \u0000 \u0000 Key words: Nutritional, anti-nutritional, functional, mineral composition.","PeriodicalId":7556,"journal":{"name":"African Journal of Pure and Applied Chemistry","volume":"28 1","pages":"167-174"},"PeriodicalIF":0.0,"publicationDate":"2015-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85908734","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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