VOLUME 40, NO6, DEC-2018

Development of Ethanol Conversion Catalysts from Various Clays

Clay-based catalysts were synthesised from non-modified bentonite and kaolin by beneficiation, acid modification and hydrothermal treatment. The effects of beneficiation and acid modification on Si/Al, catalyst morphology, mineralogical composition of clay-based catalysts were investigated. Further on, the mineralogical phase identity of the produced clay-based zeolite was studied and compared to that of a commercial zeolite. The produced clay-based zeolite was found to consist dominantly of cuboidal crystals and fits in structural framework and phase of ZSM-5 by 86.92 %. Clay-based catalysts produced in turn showed high activity in the conversion of ethanol to valuable hydrocarbons; at 350 ⁰C and reaction time 6 hours. Bentonite was the most active with 84.95 % conversion among several of raw clays, increasing to 87.3 % upon beneficiation and acid modification. Clay-based zeolite further resulted to highest activity of more than 95 % in ethanol conversion.read more

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Juvet Malonda Shabani and Yusuf Makarfi Isa

Facile Synthesis of Co3O4 Nanowires Grown on Nickel Foam with High Electrochemical Capacitance

Co3O4 nanowire arrays freely standing on nickel foam were prepared by a hydrothermal method. The detailed microstructure and morphology of Co3O4 nanowire were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) etc. The results indicated that the Co3O4 nanowires have diameters of around 80 nm and composed of many nanoparticles with diameters of about 20 nm. The electrochemical results show that Co3O4 nanowires demonstrate enhanced specific capacitance (616 F g-1) and electrochemical reversibility, and the specific capacitance of nanowires only decreased 19% after 3000 charge-discharge cyclesread more

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Bo Ren and Meiqing Fan

First-Step Anodization of Commercial Aluminum in Oxalic Acid: Activation Energy of Rate Process and Structural Features of Porous Alumina and of Aluminum Substrate as a Function of Temperature

First-step anodization of commercial aluminium was carried out in 0.3 M oxalic acid at five temperatures –10, –5, 0, 5, and 10 ºC, keeping the anodization voltage (40 V) and time (15 min) constant. It is found that the current density, charge transferred, and thickness of porous alumina film increase exponentially with anodization temperature. The activation energy of the rate process of anodization determined from the Arrhenius plots of current density, charge transferred, and film thickness is found to be 0.357 eV with a standard deviation of 0.013 eV. Structural features of the porous alumina examined by SEM show that the pore diameter, interpore distance, and porosity increase whereas pore circularity and pore density decrease linearly with the increase in anodization temperature. Moreover, XRD studies of the anodized commercial aluminum substrate show that the intensity of diffraction peak pertaining to preferentially oriented crystallographic plane (311) is decreased whereas its full width at half maximum is increased at all anodization temperatures.read more

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Syed Muhammad Junaid Zaidi and Muhammad. Zakria Butt

Mitigated Flux Attenuation of Ceramic Membrane Ultrafiltration Coupled with TiO2 Photocatalytic Oxidation Pretreatment

To aggrandize membrane flux during micro-polluted surface water ultrafiltration process, TiO2 photocatalytic oxidation pretreatment was conducted to mitigate the ultrafiltration membrane fouling. The single-factor experiments and membrane resistance analysis methods have shown that the water throughput performance in the hybrid process is affected by TiO2 concentration, aeration rate, transmembrane pressure, and crossflow velocity. Subsequently, the orthogonal methodology was further conducted to optimize the overriding variables using membrane flux as the response value. Simultaneously, parallel of UF ceramic membrane performance between chemical coagulation and TiO2 photocatalytic pretreatment was implemented and the excellent chemical washing method was determined. The results manifested that i) the impact on permeate flux was demonstrated following the order of the transmembrane pressure, crossflow velocity, aeration rate, and TiO2 concentration. The statistical optimum operating condition was acquired at 0.5 g/L additional TiO2, an aeration rate of 2 L/min, a transmembrane pressure of 0.15 MPa, and a crossflow velocity of 2.0 m/s; ii) TiO2 photocatalytic oxidation buttressed UF flux was superior to chemical coagulation pretreatment; iii) The best cleaning performance in permeability recovery was exhibited in citric acid solution after 40 minutes cycle-cleaning.read more

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Zhou Zhen, Yu Yaqin, Yao Jilun, Zhang Xing and Ding Zhaoxia

Optimization of Dynamic Microwave-Assisted Extraction of Dihydromyricetin from Ampelopsis grossedentata using Response Surface Methodology

Dihydromyricetin is a natural flavonoid and principal component of the Chinese herbal tea, Ampelopsis grossedentata, with numerous health-promoting bioactivities. Response surface methodology (RSM) was employed to optimize the extraction of dihydromyricetin from Ampelopsis grossedentata leaves using dynamic microwave assisted multi-stage countercurrent extraction. The influence of temperature, pH, time and solvent/material ratio on the yield of extraction was investigated. It was found that the extraction data were sufficiently fitted into a second-order polynomial model (R2 = 0.9992). The extraction parameters of temperature, pH and solvent/material ratio, the quadrics of time, temperature and pH, and the interaction between each two of the four extraction parameters had a significant effect on the yield. The optimal conditions for extracting dihydromyricetin were predicted to be: temperature, 96.8 °C; time, 8.8 min; solvent/material ratio, 26.4/1 and pH, 5.3. Under those conditions, the predicted yield was 92.3% of dihydromyricetin in the leaves.read more

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Wei Li, Yuzhen Chen, Xiang Xu, Cheng Zheng and Jian Zhao

Oxidative Chlorination Leaching of Stibnite Using Acidic Ferric Chloride Lixiviant

A hydrometallurgical process was developed for the preparation of commercial grade antimony trioxide (Sb2O3) from indigenous antimony ore. The developed process includes oxidative chlorination leaching of stibnite (Sb2S3) concentrate assaying 64.86% Sb prepared from indigenous low-grade ore containing 20.16% Sb using ferric chloride (FeCl3) solution in acidic medium as lixiviant followed by purification, precipitation and crystallization of antimony trioxide as end product. An effort was made to investigate the effect of all the important variables encountered in leaching of metallic sulphide minerals in order to establish the best process conditions for the extraction of antimony and subsequent preparation of antimony trioxide. The experiments were carried out on laboratory scale and the effect of various process variables on the dissolution of antimony from stibnite concentrate was studied by single factor variation method arranged in a sequential manner. An industrial grade antimony trioxide having 99.70% purity with 90.72% yield has been prepared. The developed process is technically feasible and environmentally friendly.read more

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Muhammad Arif Bhatti, Ahmad Adnan, Abdul Ahad, Kamran Raza Kazmi and Adnan Akram

Ferrocene derivatives: Potential anticancer material

The presented work is focused on the investigation of ferrocene and its derivatives (ferrocene benzoic acid and ferrocene dicarboxylic acid) via electrochemical, and spectrophotometric for biological activity. DNA binding capacity was studied by cyclic voltammetry and UV-Vis spectroscopy with evaluation of kinetic and thermodynamic parameters. Heterogeneous rate constant and diffusion coefficients were estimated for pure compounds and the compound bound with ds.DNA (double-stranded DNA). The voltammetric investigation suggested that the interaction between the ferrocene derivatives and ds.DNA was present. Oxidation potential (Ep) values showed that the interactions of ferrocene dicarboxlic acid (FC-2) with ds.DNA was stronger than that of ferrocene benzoic acid (FC-1). Diffusion coefficient and heterogeneous rate constant values also corresponded to the structural dependent interactions of these compounds with ds.DNA.read more

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Asifa Nigar, Naveed Kausar janjua, Asghari Gul, Abid Ali, Zareen Akhter, Sadia Mehmood

Composition, Physicochemical Analysis, Antimicrobial and Anti- Inflammatory Activities of the Essential Oils obtained from Ruta chalepensis. L Growing Wild in Northen of Algeria

Ruta chalepensis L is an aromatic plant belonging to Rutaceae family which is widely found in North Africa, particularly in Algeria. Our study has focused on extraction by steam distillation, physicochemical analysis, gas chromatography coupled with mass spectrometry analysis (GC-MS) and biological activity of essential oils (EOs) obtained from the aerial part of this plant, collected from the region of Hamman Melouane (Blida,Algeria).The results revealed that the extraction yield was 0.4 ± 0.03 % (w/w) and a total of seventeen compounds of essential oils were identified with 2-undecanone (35.51 %), 1- decanol-2 methyl (8.62 %) and 2-dodecanone (6.86 %) appeared as dominated compounds. Results showed also that our EOS presented an adequate quality with the following parameters: acid index; 2.86, ester index; 22.44, refractive index; 1.43 and density of 0.84.In addition, our finding revealed that the extracted oils had exerted a variable antimicrobial activity. They presented a moderate inhibition zone with diameters of 25, 27 and 28 mm against Klebsila pneumoniae ATCC4352,Saccharomyces cerevisiae ATCC2601 and Candida albicans ATCC24433 respectively.The minimum inhibitory concentration (MIC) was further investigated and it has been observed that the lowest concentration of EOs was found to be 0.03 % (v/v) against Candida albicans ATCC24433 and Saccharomyces cerevisiae ATCC2601, contrary to Klebsila pneumoniae ATCC4352 which had an MIC value of 0.125 % (v/v). Moreover, the most sensitive microorganisms to oils were Saccharomyces cerevisiae ATCC2601 and Bacillus subtilis ATCC9372 with a minimal fungicidal concentration (MFC) and minimal bactericidal concentration (MBC) of 0.06 % (v/v) and 0.125 % (v/v), respectively. Furthermore, it had exhibited a high significant anti-inflammatory activity with edema reduction rate of 53.59 % (p < 0.004).Consequently, this study highlighted that the extracted EOs could be considered as potentials anti microbial and ant-inflammatory candidates in therapeutic and pharmaceutical applications.read more

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Khaled Boudjema, Mouhouche, A. Guerdouba and L. Hali

Synthesis and Insecticidal Activity of Rotenone Analogues

Rotenone, one of traditional botanical insecticide, has been used more than one hundred years. A variety of rotenone derivatives were designed and synthesized in recent years due to environmental benign character and not easy to generate insecticide resistance. This paper described the molecular design, synthesis, and insecticidal activities of a series of rotenone analogues and 2-substituted rotenone derivatives. The preliminary bioassay showed that isorotenone and 2-rotenone nicotinate is equal to rotenone’s against Musca domestica.read more

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Liu Zhicheng, Jiang Dingxin, Xu Hanhong and Zheng Xiaohua

Study of Volumetric, Viscometric and Thermodynamics Behavior of Binary and Ternary Systems for 2,5 Hexandione with Some Alcohol Cyclic at Different Temperatures

The density and viscosity of binary and ternary mixtures of 2,5 Hexandione with cyclopentanol and cyclohexanol were measured at 298.15, 303.15, 308.15 and 313.15 K, from using this data (density and viscosity) the excess molar volume VE, Viscosition deviation ∆ɳ and activation excess parameters ∆G*E, ∆H*E and ∆S*E have been calculated. The results were fitted by Redlich-Kister equations. Negative and positive deviations are obtained for both the binary and ternary Systems at temperatures under study. This expose that the presence of intermolecular interactions in the binary and ternary mixtures.read more

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Ahmed Mohammed Abbas