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  Subjects -> CHEMISTRY (Total: 849 journals)
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    - CHEMISTRY (598 journals)
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CHEMISTRY (598 journals)                  1 2 3 | Last

Showing 1 - 200 of 735 Journals sorted alphabetically
2D Materials     Hybrid Journal   (Followers: 8)
Accreditation and Quality Assurance: Journal for Quality, Comparability and Reliability in Chemical Measurement     Hybrid Journal   (Followers: 26)
ACS Catalysis     Full-text available via subscription   (Followers: 32)
ACS Chemical Neuroscience     Full-text available via subscription   (Followers: 17)
ACS Combinatorial Science     Full-text available via subscription   (Followers: 23)
ACS Macro Letters     Full-text available via subscription   (Followers: 23)
ACS Medicinal Chemistry Letters     Full-text available via subscription   (Followers: 39)
ACS Nano     Full-text available via subscription   (Followers: 227)
ACS Photonics     Full-text available via subscription   (Followers: 11)
ACS Synthetic Biology     Full-text available via subscription   (Followers: 21)
Acta Chemica Iasi     Open Access   (Followers: 2)
Acta Chimica Sinica     Full-text available via subscription   (Followers: 1)
Acta Chimica Slovaca     Open Access   (Followers: 1)
Acta Chromatographica     Full-text available via subscription   (Followers: 9)
Acta Facultatis Medicae Naissensis     Open Access  
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 5)
Acta Scientifica Naturalis     Open Access   (Followers: 2)
adhäsion KLEBEN & DICHTEN     Hybrid Journal   (Followers: 5)
Adhesion Adhesives & Sealants     Hybrid Journal   (Followers: 7)
Adsorption Science & Technology     Full-text available via subscription   (Followers: 5)
Advanced Functional Materials     Hybrid Journal   (Followers: 50)
Advanced Science Focus     Free   (Followers: 3)
Advances in Chemical Engineering and Science     Open Access   (Followers: 53)
Advances in Chemical Science     Open Access   (Followers: 13)
Advances in Chemistry     Open Access   (Followers: 14)
Advances in Colloid and Interface Science     Full-text available via subscription   (Followers: 18)
Advances in Drug Research     Full-text available via subscription   (Followers: 22)
Advances in Enzyme Research     Open Access   (Followers: 9)
Advances in Fluorine Science     Full-text available via subscription   (Followers: 8)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 15)
Advances in Heterocyclic Chemistry     Full-text available via subscription   (Followers: 8)
Advances in Materials Physics and Chemistry     Open Access   (Followers: 19)
Advances in Nanoparticles     Open Access   (Followers: 14)
Advances in Organometallic Chemistry     Full-text available via subscription   (Followers: 15)
Advances in Polymer Science     Hybrid Journal   (Followers: 41)
Advances in Protein Chemistry     Full-text available via subscription   (Followers: 18)
Advances in Protein Chemistry and Structural Biology     Full-text available via subscription   (Followers: 19)
Advances in Quantum Chemistry     Full-text available via subscription   (Followers: 5)
Advances in Science and Technology     Full-text available via subscription   (Followers: 12)
African Journal of Bacteriology Research     Open Access  
African Journal of Chemical Education     Open Access   (Followers: 2)
African Journal of Pure and Applied Chemistry     Open Access   (Followers: 7)
Agrokémia és Talajtan     Full-text available via subscription   (Followers: 2)
Alkaloids: Chemical and Biological Perspectives     Full-text available via subscription   (Followers: 3)
AMB Express     Open Access   (Followers: 1)
Ambix     Hybrid Journal   (Followers: 3)
American Journal of Biochemistry and Biotechnology     Open Access   (Followers: 67)
American Journal of Biochemistry and Molecular Biology     Open Access   (Followers: 14)
American Journal of Chemistry     Open Access   (Followers: 26)
American Journal of Plant Physiology     Open Access   (Followers: 13)
American Mineralogist     Hybrid Journal   (Followers: 13)
Analyst     Full-text available via subscription   (Followers: 38)
Angewandte Chemie     Hybrid Journal   (Followers: 161)
Angewandte Chemie International Edition     Hybrid Journal   (Followers: 209)
Annales UMCS, Chemia     Open Access   (Followers: 1)
Annals of Clinical Chemistry and Laboratory Medicine     Open Access   (Followers: 1)
Annual Reports in Computational Chemistry     Full-text available via subscription   (Followers: 3)
Annual Reports Section A (Inorganic Chemistry)     Full-text available via subscription   (Followers: 3)
Annual Reports Section B (Organic Chemistry)     Full-text available via subscription   (Followers: 8)
Annual Review of Chemical and Biomolecular Engineering     Full-text available via subscription   (Followers: 12)
Annual Review of Food Science and Technology     Full-text available via subscription   (Followers: 14)
Anti-Infective Agents     Hybrid Journal   (Followers: 3)
Antiviral Chemistry and Chemotherapy     Hybrid Journal  
Applied Organometallic Chemistry     Hybrid Journal   (Followers: 7)
Applied Spectroscopy     Full-text available via subscription   (Followers: 23)
Applied Surface Science     Hybrid Journal   (Followers: 28)
Arabian Journal of Chemistry     Open Access   (Followers: 6)
ARKIVOC     Open Access   (Followers: 2)
Asian Journal of Biochemistry     Open Access   (Followers: 1)
Atomization and Sprays     Full-text available via subscription   (Followers: 3)
Australian Journal of Chemistry     Hybrid Journal   (Followers: 7)
Autophagy     Hybrid Journal   (Followers: 2)
Avances en Quimica     Open Access   (Followers: 1)
Biochemical Pharmacology     Hybrid Journal   (Followers: 10)
Biochemistry     Full-text available via subscription   (Followers: 286)
Biochemistry Insights     Open Access   (Followers: 5)
Biochemistry Research International     Open Access   (Followers: 6)
BioChip Journal     Hybrid Journal  
Bioinorganic Chemistry and Applications     Open Access   (Followers: 9)
Bioinspired Materials     Open Access   (Followers: 5)
Biointerface Research in Applied Chemistry     Open Access   (Followers: 2)
Biointerphases     Open Access   (Followers: 1)
Biology, Medicine, & Natural Product Chemistry     Open Access   (Followers: 1)
Biomacromolecules     Full-text available via subscription   (Followers: 19)
Biomass Conversion and Biorefinery     Partially Free   (Followers: 10)
Biomedical Chromatography     Hybrid Journal   (Followers: 6)
Biomolecular NMR Assignments     Hybrid Journal   (Followers: 3)
BioNanoScience     Partially Free   (Followers: 4)
Bioorganic & Medicinal Chemistry     Hybrid Journal   (Followers: 109)
Bioorganic & Medicinal Chemistry Letters     Hybrid Journal   (Followers: 93)
Bioorganic Chemistry     Hybrid Journal   (Followers: 10)
Biopolymers     Hybrid Journal   (Followers: 18)
Biosensors     Open Access   (Followers: 2)
Biotechnic and Histochemistry     Hybrid Journal   (Followers: 1)
Bitácora Digital     Open Access  
Boletin de la Sociedad Chilena de Quimica     Open Access  
Bulletin of the Chemical Society of Ethiopia     Open Access   (Followers: 2)
Bulletin of the Chemical Society of Japan     Full-text available via subscription   (Followers: 24)
Bulletin of the Korean Chemical Society     Hybrid Journal   (Followers: 1)
C - Journal of Carbon Research     Open Access   (Followers: 3)
Cakra Kimia (Indonesian E-Journal of Applied Chemistry)     Open Access  
Canadian Association of Radiologists Journal     Full-text available via subscription   (Followers: 2)
Canadian Journal of Chemistry     Hybrid Journal   (Followers: 10)
Canadian Mineralogist     Full-text available via subscription   (Followers: 3)
Carbohydrate Research     Hybrid Journal   (Followers: 26)
Carbon     Hybrid Journal   (Followers: 67)
Catalysis for Sustainable Energy     Open Access   (Followers: 6)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (Followers: 8)
Catalysis Science and Technology     Free   (Followers: 6)
Catalysis Surveys from Asia     Hybrid Journal   (Followers: 3)
Catalysts     Open Access   (Followers: 7)
Cellulose     Hybrid Journal   (Followers: 7)
Cereal Chemistry     Full-text available via subscription   (Followers: 4)
ChemBioEng Reviews     Full-text available via subscription   (Followers: 1)
ChemCatChem     Hybrid Journal   (Followers: 8)
Chemical and Engineering News     Free   (Followers: 12)
Chemical Bulletin of Kazakh National University     Open Access  
Chemical Communications     Full-text available via subscription   (Followers: 70)
Chemical Engineering Research and Design     Hybrid Journal   (Followers: 23)
Chemical Research in Chinese Universities     Hybrid Journal   (Followers: 3)
Chemical Research in Toxicology     Full-text available via subscription   (Followers: 19)
Chemical Reviews     Full-text available via subscription   (Followers: 174)
Chemical Science     Open Access   (Followers: 21)
Chemical Technology     Open Access   (Followers: 16)
Chemical Vapor Deposition     Hybrid Journal   (Followers: 5)
Chemical Week     Full-text available via subscription   (Followers: 8)
Chemie in Unserer Zeit     Hybrid Journal   (Followers: 55)
Chemie-Ingenieur-Technik (Cit)     Hybrid Journal   (Followers: 25)
ChemInform     Hybrid Journal   (Followers: 8)
Chemistry & Biodiversity     Hybrid Journal   (Followers: 6)
Chemistry & Biology     Full-text available via subscription   (Followers: 30)
Chemistry & Industry     Hybrid Journal   (Followers: 5)
Chemistry - A European Journal     Hybrid Journal   (Followers: 146)
Chemistry - An Asian Journal     Hybrid Journal   (Followers: 15)
Chemistry and Materials Research     Open Access   (Followers: 18)
Chemistry Central Journal     Open Access   (Followers: 4)
Chemistry Education Research and Practice     Free   (Followers: 5)
Chemistry in Education     Open Access   (Followers: 9)
Chemistry International     Hybrid Journal   (Followers: 2)
Chemistry Letters     Full-text available via subscription   (Followers: 45)
Chemistry of Materials     Full-text available via subscription   (Followers: 239)
Chemistry of Natural Compounds     Hybrid Journal   (Followers: 9)
Chemistry World     Full-text available via subscription   (Followers: 22)
Chemistry-Didactics-Ecology-Metrology     Open Access  
ChemistryOpen     Open Access   (Followers: 2)
Chemkon - Chemie Konkret, Forum Fuer Unterricht Und Didaktik     Hybrid Journal  
Chemoecology     Hybrid Journal   (Followers: 2)
Chemometrics and Intelligent Laboratory Systems     Hybrid Journal   (Followers: 15)
Chemosensors     Open Access  
ChemPhysChem     Hybrid Journal   (Followers: 9)
ChemPlusChem     Hybrid Journal   (Followers: 2)
ChemTexts     Hybrid Journal  
CHIMIA International Journal for Chemistry     Full-text available via subscription   (Followers: 2)
Chinese Journal of Chemistry     Hybrid Journal   (Followers: 6)
Chinese Journal of Polymer Science     Hybrid Journal   (Followers: 10)
Chromatographia     Hybrid Journal   (Followers: 24)
Chromatography Research International     Open Access   (Followers: 7)
Clay Minerals     Full-text available via subscription   (Followers: 9)
Cogent Chemistry     Open Access  
Colloid and Interface Science Communications     Open Access  
Colloid and Polymer Science     Hybrid Journal   (Followers: 10)
Colloids and Surfaces B: Biointerfaces     Hybrid Journal   (Followers: 8)
Combinatorial Chemistry & High Throughput Screening     Hybrid Journal   (Followers: 3)
Combustion Science and Technology     Hybrid Journal   (Followers: 18)
Comments on Inorganic Chemistry: A Journal of Critical Discussion of the Current Literature     Hybrid Journal   (Followers: 2)
Composite Interfaces     Hybrid Journal   (Followers: 6)
Comprehensive Chemical Kinetics     Full-text available via subscription   (Followers: 2)
Comptes Rendus Chimie     Full-text available via subscription  
Comptes Rendus Physique     Full-text available via subscription   (Followers: 1)
Computational and Theoretical Chemistry     Hybrid Journal   (Followers: 9)
Computational Biology and Chemistry     Hybrid Journal   (Followers: 12)
Computational Chemistry     Open Access   (Followers: 2)
Computers & Chemical Engineering     Hybrid Journal   (Followers: 9)
Coordination Chemistry Reviews     Full-text available via subscription   (Followers: 2)
Copernican Letters     Open Access  
Critical Reviews in Biochemistry and Molecular Biology     Hybrid Journal   (Followers: 5)
Crystal Structure Theory and Applications     Open Access   (Followers: 3)
CrystEngComm     Full-text available via subscription   (Followers: 11)
Current Catalysis     Hybrid Journal   (Followers: 2)
Current Metabolomics     Hybrid Journal   (Followers: 5)
Current Opinion in Colloid & Interface Science     Hybrid Journal   (Followers: 9)
Current Research in Chemistry     Open Access   (Followers: 8)
Current Science     Open Access   (Followers: 56)
Dalton Transactions     Full-text available via subscription   (Followers: 20)
Detection     Open Access   (Followers: 2)
Developments in Geochemistry     Full-text available via subscription   (Followers: 2)
Diamond and Related Materials     Hybrid Journal   (Followers: 12)
Dislocations in Solids     Full-text available via subscription  
Doklady Chemistry     Hybrid Journal  
Drying Technology: An International Journal     Hybrid Journal   (Followers: 4)
Eclética Química     Open Access   (Followers: 1)
Ecological Chemistry and Engineering S     Open Access   (Followers: 4)
Ecotoxicology and Environmental Contamination     Open Access  
Educación Química     Open Access   (Followers: 1)
Education for Chemical Engineers     Hybrid Journal   (Followers: 5)
EJNMMI Radiopharmacy and Chemistry     Open Access  
Elements     Full-text available via subscription   (Followers: 2)
Environmental Chemistry     Hybrid Journal   (Followers: 9)
Environmental Chemistry Letters     Hybrid Journal   (Followers: 4)
Environmental Science & Technology Letters     Full-text available via subscription   (Followers: 5)

        1 2 3 | Last

Journal Cover Bulletin of the Chemical Society of Ethiopia
  [SJR: 0.239]   [H-I: 14]   [2 followers]  Follow
    
  This is an Open Access Journal Open Access journal
   ISSN (Print) 1011-3924
   Published by African Journals Online Homepage  [266 journals]
  • Application of 4-(2-pyridylazo)resorcinol for flotation-spectrophotometric
           determination of iron

    • Authors: G. K. Toncheva, K. B. Gavazov, Z. G. Georgieva, L. K. Dospatliev, A. B. Peltekov, B. S. Boyanov
      Abstract: Optimum conditions for flotation-spectrophotometric determination of iron with 4-(2-pyridylazo)resorcinol (PAR) based on a 1:2 FeII-PAR complex were found to be as follows: flotation solvent (chloroform), shaking time (2 min), pH (4.5±0.5), concentration of PAR (2.0×10–4 mol L–1), reducing agent (hydroxylamine hydrochloride), solvent for the floated compound (dimethylsulphoxide, DMSO), wavelength for spectrophotometric measurements (718 nm), and volumes of the organic solvents (5 mL of chloroform and 3 mL of DMSO). Calibration graphs were compared for different volumes of the aqueous phase – 10 mL and 40 mL; the corresponding linear ranges were 0.30–1.3 mg mL–1 and 0.25–1.0 mg mL–1. The iron content was successfully determined in soil samples, reference standard materials (PS-1, COOMET No. 0001-1999 BG, SОD No. 310а-98; PS-2, COOMET No. 0002-1999 BG, SOD No. 311а-98; and PS-3, COOMET No. 0003-1999 BG, SOD No. 312а-98) and zinc sulfide concentrates. KEY WORDS: Iron(II), Fe-PAR complex, Flotation, Spectrophotometry, Soils, Zinc sulfide concentrates Bull. Chem. Soc. Ethiop. 2016, 30(3), 325-332.
      DOI : http://dx.doi.org/10.4314/bcse.v30i3.1
      PubDate: 2017-01-14
      Issue No: Vol. 30, No. 3 (2017)
       
  • Spectrophotometric methods based on charge transfer complexation reaction
           for the determination of some antifungal drugs in pure and dosage forms

    • Authors: A. A. Gouda, R. El Sheikh, A. S. Amin, S. H. Ibrahim
      Abstract: Charge transfer complexes of some antifungal drugs fluconazole (FLU), sertaconazole nitrate (SER) and miconazole nitrate (MCO) as electron donor with the σ-acceptor iodine (I2) and 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ), p-chloranilic acid (p-CLA) and 7,7,8,8-tetracyanoquinodimethane (TCNQ) as π-acceptors in acetonitrile were investigated. The formation of the colored charge-transfer complexes were utilized in the development of simple, rapid and accurate spectrophotometric methods for the analysis of the cited drugs in pure forms and pharmaceutical formulations at 365 nm for MCO and SER using I2 method, at 460 nm for FLU and SER using DDQ method, at 535 and 530 nm for FLU and SER, respectively, using p-CLA method and at 842 nm for MCO and SER using TCNQ method. The optimum experimental conditions have been studied carefully and optimized. Beer’s law was obeyed over the concentration ranges of 2.0–28, 10–240 and 2.0–160 µg mL−1 for MCO, FLU and SER, respectively, with good correlation coefficients (0.9996–0.9999). Molar absorpitivity, Sandell sensitivity, relative standard deviation, limit of detection and quantification were calculated. The obtained data refer to high accuracy and precision of the proposed method. The obtained results were confirmed by inter and intra-day accuracy and precision with percent recovery of 99.1–100%, 99.3–101% and 99.1–101% for MCO, FLU and SER, respectively. These data were compared with those obtained using official methods for the determination of the cited drugs. The proposed methods were applied successfully for simultaneous determination of the cited drugs in their pharmaceutical formulations with good accuracy and precision and without interferences from common additives. KEY WORDS: Fluconazole, Sertaconazole nitrate, Miconazole nitrate, Charge transfer complexes, Spectrophotometry, Pharmaceutical formulations Bull. Chem. Soc. Ethiop. 2016, 30(3), 333-346.
      DOI : http://dx.doi.org/10.4314/bcse.v30i3.2  
      PubDate: 2017-01-14
      Issue No: Vol. 30, No. 3 (2017)
       
  • Phenolic composition and antioxidant activities of cladodes of the two
           varieties of cactus pear (Opuntia ficus-indica) grown in Ethiopia

    • Authors: K. Haile, B. Mehari, M. Atlabachew, B. S. Chandravanshi
      Abstract: In this study, young cladodes corresponding to two (thorn-less and thorn-containing) varieties of cactus pear (Opuntia ficus-indica) from four different areas of Tigray region, Ethiopia, were investigated for their phenolic contents and antioxidant activities. Quantitative estimation of total phenolic contents and antioxidant activities in the cladodes was carried out using spectrophotometric methods. A 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging assay was used for the determination of the antioxidant activities, while Folin-Ciocalteau reagent, aluminum chloride and protein (albumin) precipitation methods were used for the determination of total polyphenol, flavonoid and tannin contents, respectively. The cladodes were found to be rich in polyphenols, with values in the range 18.0-71.4 mg gallic acid equivalent (GAE)/g of dry weight (DW). The predominant part of the polyphenols is represented by tannins, 9.00-41.2 mg GAE/g of DW, followed by flavonoids, 6.40-25.0 mg catchin equivalent (CE)/g of DW. The cladodes showed strong antioxidant activities, 59.3-85.8% inhibition compared to ascorbic acid. Application of paired t-test on the overall mean total polyphenol contents of samples collected from the different areas revealed the presence of significant variation between the thorn-less (31.6 GAE/g of DW) and thorn-containing (47.7 GAE/g of DW) varieties. One-way ANOVA also revealed that there are significant variations among samples from the same variety but collected from different areas. KEY WORDS: Opuntia ficus-indica, Flavonoids, Tannins, Polyphenols, Antioxidant activities, Ethiopia Bull. Chem. Soc. Ethiop. 2016, 30(3), 347-356.
      DOI : http://dx.doi.org/10.4314/bcse.v30i3.3
      PubDate: 2017-01-14
      Issue No: Vol. 30, No. 3 (2017)
       
  • Thermodynamic studies on the adsorption of Cu2+, Ni2+ and Cd2+ on to
           amine-modified bentonite

    • Authors: X. Zhu, L. Lan, N. Xiang, W. Liu, Q. Zhao, H. Li
      Abstract: Amine-modified bentonite (TEPA-Bn) has been prepared with tetraethylenepentamine (TEPA) as a modifier. The structure of Ca-based bentonite (Ca-Bn), TEPA-Bn and TEPA-Bn after adsorbing Cu2+,Ni2+,Cd2+ had been characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) and simultaneous thermal gravimetric/differential thermal gravimetric (TG/DTG) analysis. The TEPA had been intercalated into Ca-Bn interlayer space but had not changed its original crystal structure. The thermal stability of TEPA-Bn was stronger than Ca-Bn while the hydrophilicity of it reduced. The adsorption ability of TEPA-Bn to Cd2+, Ni2+, Cu2+ was much better than Ca-Bn, the saturated adsorption capacity to Cd2+, Ni2+, Cu2+ were 14.88, 8.88 and 13.05 times as much as Ca-Bn, respectively. The adsorption behavior of Cu2+, Ni2+, Cd2+ on to TEPA-Bn were studied by isothermal models, including Freundlich, Langmuir, Dubinin-Radushkevich Florry-Huggins, and Tempkin models. The Freundlich model simulated the experimental data best, the adsorption of Cu2+, Ni2+, Cd2+ onto TEPA-Bn was a multilayer, heterogeneous chemical process. The variety of thermodynamic parameters (DH > 0, DS > 0, DG < 0) under different temperature indicated that the adsorption process of Cu2+, Ni2+, Cd2+ on TEPA-Bn was endothermic and spontaneous. KEY WORDS: Amine-modified bentonite, TEPA, Heavy metal ions, Adsorption thermodynamics, Characterization Bull. Chem. Soc. Ethiop. 2016, 30(3), 357-367
      DOI : http://dx.doi.org/10.4314/bcse.v30i3.4
      PubDate: 2017-01-14
      Issue No: Vol. 30, No. 3 (2017)
       
  • Adsorption of polynuclear aromatic hydrocarbons from aqueous solution:
           Agrowaste-modified kaolinite vs surfactant modified bentonite

    • Authors: E. I. Unuabonah, B. I. Olu-Owolabi, L. Böhm, R. A. Düring
      Abstract: . The adsorption efficiency of a new hybrid clay adsorbent for polynuclear aromatic hydrocarbons (PAHs) is compared with known modified clay adsorbents. The new hybrid clay adsorbent (HYCA) showed far higher adsorption capacities for the adsorption of various PAH molecules compared with sodium dodecyl sulfate modified and humic acid modified Bentonite clay adsorbents. With the new hybrid clay adsorbent (HYCA), the adsorption of some of the larger PAH molecules was complete in the first 1 h as compared with ≈ 62% and ≈ 76% observed for both humic acid modified and sodium dodecyl sulfate modified Bentonite clay adsorbents respectively. In 24 h adsorption of the PAHs was complete for all adsorbents with HYCA adsorbent showing better efficiency in the removal of the PAH molecules from aqueous solutions. No significant change was observed with increase in time up to 48 h. The adsorption was observed to be more spontaneous with HYCA adsorbent than with either modified Bentonite adsorbents. The enthalpy of adsorption did not follow any specific order and were not consistent for all PAH molecules considered. KEY WORDS: Adsorption, Polynuclear aromatic hydrocarbons, Enthalpy, Hybrid clay, Bentonite Bull. Chem. Soc. Ethiop. 2016, 30(3), 369-376
      DOI : http://dx.doi.org/10.4314/bcse.v30i3.5
      PubDate: 2017-01-14
      Issue No: Vol. 30, No. 3 (2017)
       
  • Adsorptive approach on nepholometric study of paint effluent using
           Tympanotonos fuscatus extract

    • Authors: I. G. Ezemagu, M. C. Menkiti, V. I. Ugonabo, M. C. Aneke
      Abstract: Adsorptive study of paint effluent coagulation using T. fuscatus coagulant (TFC) is investigated. Effects of pH, dose, time, and temperature were investigated. Functional group, crystalline, morphology and thermal characteristics of samples were determined. Equilibrium data were analysed by Langmuir, Freundlich, Temkin, Frumkin, and Dubinin-Radushkevich (D-R) isotherms. Kinetic data were fitted to reversible first order, pseudo-first-order, pseudo-second-order, Elovich, intra-particle diffusion and Boyd kinetic models. Process Gibbs free energy (∆G°), enthalpy (∆H°) and the entropy (∆S°) were evaluated. The process was best described by Langmuir isotherm (R2 > 0.99; X2 ˂ 0.6; SSE ˂ 0.7). Pseudo second order best fitted the kinetic data. The process was spontaneous, feasible and endothermic. 97% optimal removal was achieved at pH 5. Tympanotonos fuscatus extract has potential for application as an effective coagulant while showing significant component of adsorptive phenomenon KEY WORDS: Paint effluent, Coagulation/flocculation, Adsorption, Tympanotonos fuscatus Bull. Chem. Soc. Ethiop. 2016, 30(3), 377-390.
      DOI : http://dx.doi.org/10.4314/bcse.v30i3.6
      PubDate: 2017-01-14
      Issue No: Vol. 30, No. 3 (2017)
       
  • Combined aluminium sulfate/hydroxide process for fluoride removal from
           drinking water

    • Authors: F. Zewge
      Abstract: In this study, aluminium hydro(oxide), AO was prepared from locally available aluminium sulfate, and used for fluoride removal from water by combining with Nalgonda Technique. The fluoride removal performance of the combined process was investigated as a function of contact time, proportion of alum-lime/AO dose, initial fluoride concentration and solution pH in series of batch experiments. The rate of fluoride removal was investigated using conventional kinetic models. The fluoride removal efficiency of the combined process was also tested for real water sample from selected community water supply system in the Rift Valley Region of Ethiopia. The removal of fluoride was rapid in the first 15 min. The combined process efficiency was about 93% with an optimum combined alum/AO dose (80 mg alum/mg F, 5 mg AO/mg F and lime = 35% of alum) using initial fluoride concentration of 15 mg/L. The optimum solution pH for fluoride removal was in the range of 5-9, which is suitable for practical application in the Ethiopia Rift Valley Region. Kinetic studies showed that the rate of fluoride removal by alum/AO can be well described by a pseudo-second-order rate equation with an average rate constant of 0.096 g/min.mg. The optimum dose required to attain 85-93% fluoride removal efficiency from real water sample was 90 mg alum/mg F, 5 mg AO/mg F, and 15% lime. Hence, the combined defluoridation process has higher fluoride removal efficiency than the Nalgonda Technique with an additional advantage of minimizing chemical dose. The reported removal efficiency of Nalgonda Technique is 70% at alum dose of 150-170 mg alum/mg F. Besides, sludge production is also minimized. Therefore, this process is highly efficient and could be applied in areas where the fluoride concentration is higher than 10 mg/L, both at household and community level. KEY WORDS: Nalgonda Technique, Aluminium sulfate, Aluminium hydroxide, Fluoride, Drinking water Bull. Chem. Soc. Ethiop. 2016, 30(3), 391-401
      DOI : http://dx.doi.org/10.4314/bcse.v30i3.7
      PubDate: 2017-01-14
      Issue No: Vol. 30, No. 3 (2017)
       
  • Synthesis, structural and antibacterial study of new silver complex with
           3-acetyl-2H chromene-2-one

    • Authors: Z. Ali, S. R. Gilani, H. Hussain, H. Rehman, I. Hussain, M. A. Gilani, F. Rabbani
      Abstract: A new silver complex [Ag(C11H8O3)2]NO3 was synthesized by the reaction of silver nitrateand coumarin based ligand (3-acetyl-2H-chromene-2-one) through solution method. The product was characterized using different analytical techniques like melting point, Infrared spectroscopy, Raman spectroscopy, powder X-ray diffraction, thermogravimetric analysis, scanning electron microscopy, atomic absorption spectroscopy and mass spectrometry. An antibacterial study of the complex was also studied for its possible use in medical treatment. KEY WORDS: Silver complex, Acetyl coumarin, Vibrational analysis, Antibacterial study Bull. Chem. Soc. Ethiop. 2016, 30(3), 403-411
      DOI : http://dx.doi.org/10.4314/bcse.v30i3.8
      PubDate: 2017-01-14
      Issue No: Vol. 30, No. 3 (2017)
       
  • Silica nanoparticles as a highly efficient catalyst for the one-pot
           synthesis of sterically congested 2-(dibenzylamino)-2-aryl acetamide
           derivatives from by phthaldehyde isomers, isocyanides and dibenzylamine

    • Authors: A. Ramazani, Z. Shaghaghi, H. Aghahosseini, P. A. Asiabi, S. W. Joo
      Abstract: A green and efficient method for the preparation of 2-(dibenzylamino)-2-aryl acetamide derivatives via a three-component reaction of an isocyanide, dibenzylamine and a phthalaldehyde derivative in the presence of silica nanoparticles (silica NPs, ca. 42 nm) as a catalyst under solvent free conditions at room temperature is described. The ease of work-up, green chemistry conditions and high yields of the products make this procedure a useful addition to modern synthetic methods. The silica nanoparticles that used in this reaction as a catalyst were prepared by thermal decomposition of rice hulls. Simple, green and cheap method for the preparation of the nanocatalyst represents a major advantage for this process. The structures of these compounds were confirmed by IR, 1H and 13C NMR spectroscopy. KEY WORDS: Silica nanoparticles, Nanocatalyst, Isocyanide, Phthalaldehyde Bull. Chem. Soc. Ethiop. 2016, 30(3), 413-420
      DOI : http://dx.doi.org/10.4314/bcse.v30i3.9
      PubDate: 2017-01-14
      Issue No: Vol. 30, No. 3 (2017)
       
  • Synthesis and antibacterial evaluation of some novel mannich bases of
           benzimidazole derivatives

    • Authors: A. Ahmadi
      Abstract: Substituted benzimidazoles are known for their chemotherapeutic importance and many pharmacological properties. In this paper, we synthesized some novel Mannich bases of benzimidazole derivatives. The synthesized compounds were characterized by their physical and spectral data and in vitro antibacterial activity of these compounds tested against Bacillus subtilis, Bacillus pumilus, Escherichia coli and Pseudomonas aeruginosa organisms. The potency of the synthesized compounds was determined against standard drug Ciprofloxacin by measuring the zone of inhibition. KEY WORDS: Benzimidazole, Mannich base, Antimicrobial activity Bull. Chem. Soc. Ethiop. 2016, 30(3), 421-425.
      DOI : http://dx.doi.org/10.4314/bcse.v30i3.10
      PubDate: 2017-01-14
      Issue No: Vol. 30, No. 3 (2017)
       
  • Cytotoxic flavonoids from Erythrina caffra Thunb

    • Authors: Z. Y. Desta, N. Sewald, R. R.T. Majinda
      Abstract: Erythrina caffra is an important medicinal plant native to South Africa. Its stem bark was investigated for the flavonoid constituents and biological activity. Some isolated flavonoids, 3, 5, 6, 8, 9, 10, 11, 12,  13, 15 and  16  were found to be active against the human cervix carcinoma KB-3-1 cells with IC50 values in the micromolar range. Compounds 8, 9, 11, 13 and 15 also showed weak to moderate antibacterial activity against some organisms using the disc diffusion assay at loadings of 62.5 μg/disc (8, 11) and 125 μg/disc (9, 13, 15). KEY WORDS: Erythrina caffra, Cytotoxicity, Antibacterial, Flavonoids, Fabaceae Bull. Chem. Soc. Ethiop. 2016, 30(3), 427-435
      DOI : http://dx.doi.org/10.4314/bcse.v30i3.11
      PubDate: 2017-01-14
      Issue No: Vol. 30, No. 3 (2017)
       
  • Diversion of the melanin synthetic pathway by dopamine product scavengers:
           A quantum chemical modeling of the reaction mechanisms

    • Authors: T. B. Demissie, G. Y. Ashebir
      Abstract: We report the stability and reactivity of the oxidation products as well as L-cysteine and N-acetylcysteine adducts of dopamine studied using quantum chemical calculations. The overall reactions studied were subdivided into four reaction channels. The first reaction channel is the oxidation of dopamine to form dopaminoquinone. The second reaction channel leads to melanin formation through subsequent reactions. The third and fourth reaction channels are reactions leading to the formation of dopaminoquinone adducts which are aimed to divert the synthesis of melanin. The results indicate that L-cysteine and N-acetylcysteine undergo chemical reactions mainly at C5 position of dopaminoquinone. The analyses of the thermodynamic energies indicate that L-cysteine and N-acetylcysteine covalently bind to dopaminoquinone by competing with the internal cyclization reaction of dopaminoquinone which leads to the synthesis of melanin. The analysis of the results, based on the reaction free energies, is also supported by the investigation of the natural bond orbitals of the reactants and products. KEY WORDS: Dopamine, Melanin, L-Cysteine, N-Acetylcysteine, DFT calculations Bull. Chem. Soc. Ethiop. 2016, 30(3), 437-448
      DOI : http://dx.doi.org/10.4314/bcse.v30i3.12
      PubDate: 2017-01-14
      Issue No: Vol. 30, No. 3 (2017)
       
  • Improving the properties of mild steel by ternary multilayer composite
           coating via electrodeposition route

    • Authors: O. S.I. Fayomi, A. P.I. Popoola, T. Monyai
      Abstract: We report the stability and reactivity of the oxidation products as well as L-cysteine and N-acetylcysteine adducts of dopamine studied using quantum chemical calculations. The overall reactions studied were subdivided into four reaction channels. The first reaction channel is the oxidation of dopamine to form dopaminoquinone. The second reaction channel leads to melanin formation through subsequent reactions. The third and fourth reaction channels are reactions leading to the formation of dopaminoquinone adducts which are aimed to divert the synthesis of melanin. The results indicate that L-cysteine and N-acetylcysteine undergo chemical reactions mainly at C5 position of dopaminoquinone. The analyses of the thermodynamic energies indicate that L-cysteine and N-acetylcysteine covalently bind to dopaminoquinone by competing with the internal cyclization reaction of dopaminoquinone which leads to the synthesis of melanin. The analysis of the results, based on the reaction free energies, is also supported by the investigation of the natural bond orbitals of the reactants and products. KEY WORDS: Dopamine, Melanin, L-Cysteine, N-Acetylcysteine, DFT calculations Bull. Chem. Soc. Ethiop. 2016, 30(3), 437-448
      DOI : http://dx.doi.org/10.4314/bcse.v30i3.12
      PubDate: 2017-01-14
      Issue No: Vol. 30, No. 3 (2017)
       
  • Solvent effect on protonation of tpps in water-DMF mixtures

    • Authors: A. Farajtabar, M. Faeli
      Abstract: The protonation of 5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrin was investigated in aqueous solutions of N,N-dimethyformamide at 25 °C and 0.1 mol.dm-3 sodium perchlorate. The solvent effect on value of protonation constant was examined by using the linear solvation energy relationship concept. The value of logK1,logK2 and logKt was correlated with the macroscopic (dielectric constant) and microscopic Kamlet-Taft parameters (a, b and p*) of binary mixtures. The solvent effects were analyzed in the terms of Kamlet, Abboud and Taft model (KAT). Multiple linear regression were used to find the contribution of the microscopic parameters containing a (hydrogen-bond acidity), p* (dipolarity/polarizability) and b (hydrogen-bond basicity). It was found that a and b were the most predominant descriptors. Also, relationship with reciprocal of dielectric constant was obtained based on Born’s model, showing the significance of specific solute-solvent interactions. Therefore the hydrogen bonding interactions between solute and solvent components are mainly responsible for the change in protonation constants of 5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrin in water- N,N-dimethyformamid binary mixtures. KEY WORDS: Protonation, TPPS, Solvent effects, Aqueous mixture, DMF Bull. Chem. Soc. Ethiop. 2016, 30(3), 457-464
      DOI : http://dx.doi.org/10.4314/bcse.v30i3.14
      PubDate: 2017-01-14
      Issue No: Vol. 30, No. 3 (2017)
       
  • Characterization of date palm fronds as a fuel for energy production

    • Authors: S. A. Sulaiman, H. S. Bamufleh, S. N.A. Tamili, M. Inayat, M. Y. Naz
      Abstract: This study investigated the characteristics of date palm fronds (DPF) for their use as a feedstock for fuel and energy production. The calorific values and elemental contents of the DPF samples were measured through proximate analysis, ultimate analysis and energy dispersive X-ray spectroscopy. For proximate analysis, thermo-gravimetric analysis technique was used to identify the moisture content, volatile matter, fixed carbon and ash content. Ultimate analysis was used to determine the weight percentage of carbon, hydrogen and nitrogen. In line with this, X-ray fluorescence was used to determine the percentage of sulfur in the tested samples. The results of the conducted study were compared with other biomass reported in the past literature. The fixed carbon content of DPF was found lower than the other biomass except rice husk. Ajwah DPF exhibited the highest carbon content of 14.1%, while Jeddah DPF showed lowest carbon content of 5.2% among all the tested samples. However, presence of the metallic elements in the samples, such as Mg and Na can cause problems in the thermo-chemical processing systems.                KEY WORDS: Date palm fronds, Biomass, Proximate analysis, Ultimate analysis, Calorific value, Elemental content Bull. Chem. Soc. Ethiop. 2016, 30(3), 465-472
      DOI : http://dx.doi.org/10.4314/bcse.v30i3.15
      PubDate: 2017-01-14
      Issue No: Vol. 30, No. 3 (2017)
       
  • Adsorption of Pb(II) ions from aqueous solution using lignin from Hagenia
           abyssinica

    • Authors: B. Tesfaw, F. Chekol, S. Mehretie, S. Admassie
      Abstract: The adsorption of lead(II) ions from aqueous solution onto alkali lignin extracted from Hagenia abyssinica was investigated by electrochemical methods. The effect of solution pH, lignin dosage and contact time were investigated at room temperature in a batch system. Adsorption equilibrium was approached within 80 min. The adsorption kinetics data were described by pseudo-second-order kinetics model, while the equilibrium data were well fitted using the Freundlich model. A maximum adsorption capacity was found to be 80.41 mg g-1 of the dry weight of lignin. KEY WORDS: Lignin, Adsorption Capacity, Lead(II) ion, Square wave anodic stripping voltammetry Bull. Chem. Soc. Ethiop. 2016, 30(3), 473-484
      DOI : http://dx.doi.org/10.4314/bcse.v30i3.16
      PubDate: 2017-01-14
      Issue No: Vol. 30, No. 3 (2017)
       
 
 
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