VOLUME 45, NO2, APR-2023

Removal of Textile Dye from Aqueous Solution Using Immobilized Cells on Column pozzolana Bed Reactor

Textile dyes are hazardous and carcinogenic materials. Hence, their removal from wastewater is globally required. This research aims to remove anionic dye red bemacid E-TL from aqueous solutions using a biofilm supported on granular pozzolana in a fixed-bed column. The effect of different experimental conditions such as influent dye concentrations, flow rate and bed depth on red bemacid biosorption at room temperature were investigated. Results indicated that the breakthrough and saturation time increase with the decrease of the flow rate. The same effect is shown when the bed depth is increased. Favorable conditions for dye removal were observed with 60 cm of column height, lowest flow rate 1mL/min and initial red bemacid concentration of 60 mg/L; at which the highest removal efficiency of 52,68% were recorded. The breakthrough data obtained for RB E-TL removal fitted Thomas and Yoon-Nelson model with high correlation coefficients (R2 = 0,992). The results obtained proved that fixed microorganisms biomass could be a promising biosorbent for the removal of red bemacid from aqueous solutions in a dynamic process.read more

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Cherifi Souad, Djafer Abderrahmane, Mehdaoui Razika, Sameut Bouhaik Izzeddine, Fizir Meriem and Iddou Abdelkader

Extraction and Characterization of Microcrystalline Cellulose from Walnut, Almond and Apricot Stone Shells

Walnut, Almond and Apricot stone shells are abundantly available agro wastes worldwide and are sources of cellulose. In this study microcrystalline cellulose were isolated from these renewable biomasses through acid hydrolysis method. Isolation of microcrystalline was performed due to its potential significance in cosmetics, medicine and food industries. Acid hydrolysis is carried out at different concentrations of sulphuric acid. Surface morphology and elemental composition of microcrystalline cellulose was characterized with Scanning electron microscopy, energy dispersive x-ray spectroscopy and FT-IR spectroscopy. SEM clearly showed that microcrystalline cellulose obtained through high acid concentration has better structural similarities with commercial microcrystalline cellulose However microcrystalline cellulose obtained with low concentration of acid showed lower fibrillation. Elemental analysis revealed that amount of Sulphur impurity (1.17-1.18) is present in microcrystalline cellulose when hydrolyzed with high H2SO4 concentration while negligible (0.10-0.72) in microcrystalline cellulose treated with low concentration of H2SO4. It is also found that carbon and oxygen contents range in Walnut, almond and Apricot C; 50.89-58.73, 54.07-55.58, 54.19-55.62, O; 39.72-48.01, 43.54-43.71 and 41.75-44.34 respectively while FT-IR shows required functional groups in prepared MCC specifically representing beta 1-4 glycosidic linkage at 849 cm-1 that depicts improved cellulose content with in the sample. Thus, this work confirms that Walnut, Almond and Apricot stone are promising sources for microcrystalline cellulose.read more

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Shaista Nazir, Usama Habib and Tehzeeb Ul Islam

Optimization of the Production of Epichlorohydrin Catalyzed by TS-1 Using the Taguchi Method

Mass production of Epichlorohydrin (ECH) via epoxidizing allyl chloride suffers from determining the optimal reaction parameters and reproducibility. Titanium silicalite-1 (TS-1) catalyst has been successfully employed to reduce activation energy, but many reaction conditions are involved in the process. To optimize ECH production by analysing its yields, Taguchi method was implemented for reducing time and cost. Included in the reaction parameters were reaction temperature, reaction time and the reactant ratio. This study investigated preparation of heterogeneous catalysts using hydrothermal method and their characterization by XRD, IR, SEM and TEM, which confirmed the presence of ordered MFI structure. Plots of S/N suggested that reaction time was the most influential factor, followed by reaction time in ECH production. The optimum factor parameters were acquired as follows, a reaction time of 40 min, reaction temperature of 90 oC and the molar ratio of H2O2: allyl chloride equal to 1. Aimed at the final confirmation, ECH production experiment was also practiced. Established on the obtained results, the yield of ECH was hugely upgraded to the value of 83.13±1.03 % with only ~0.7% deviated from predicted value.read more

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Rui Pan, Rumeng Jiang, Yao Chen and Jiancheng Zhou

Essential Oil Composition and Menthol Production of Mint Types Grown in Different Regions in Turkey

Menthol is one of the key components of mint oil and it is a chemical component that is widely used in many sectors such as cosmetics, medicine, and food. Menthol can be made by synthesis or by various extraction and distillation methods. In this study, first, mint oil was obtained by microwave extraction and hydrodistillation from the mint that is an agricultural and industrial product cultivated in a wide geography in Turkey. Later, qualitative and quantitative analysis of this oil was executed and the differences in the chemical contents of the oils manufactured by different methods and the amount of menthol contained were compared. Lastly purification of the menthol from the oils was done. The dissimilarities in the chemical contents of the oils were compared with GC-MS analysis. The amount of menthol % obtained as a result of the studies was found as 31.65 by titration method and 29.58 by gradual crystallization. The melting point range of menthol separated from mint oil by gradual crystallization was found as 42.4 - 43.1oC as stated in the literature.read more

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Cenk Subutay, Özge Karavil, İ. Metin Hasdemir, Belma Hasdemir and Dilek Özmen

Electrochemical Study of the Hydrogen Evolution Reaction using Coppe r(II) Thiacalix[4]arene-based Catalyst

Despite the interesting structure of the generic thiacalix[4]arene containing four coordinating sulfur atoms bridging four phenolic units, there are only a few reported examples of thiacalixarene-based coordination complexes that are used as electrocatalysts. Herein, we report electrocatalytic hydrogen evolution reaction (HER) by a thiacalix[4]arene-based copper(II) complex (1). As expected, two reduction waves were appeared (-0.48 V and -1.30 V vs Ag/AgCl) for Cu2+/Cu+ and Cu+/Cu reduction couples. The HER by proton reduction occurs at -1.03 V with a shift of 0.27 V compared to the second peak potential at -1.30 V. The increase in the number of acetic acid equivalents, from 0 to 17.5 with a frequency of 2.5 eq, was accompanied by an increase in the peak current that reached a maximum value of 183 µA for 15 equivalents of acetic acid.read more

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Hani El Moll, Khalaf M. Alenezi, Abdallah O. Alshammari, Ashanul Haque, Jamal Humaidi Raoudha Soury, Eid M. S. Azzam, Fahad Abdulaziz, Salman Latif, Milan Vraneš

New Approaches for the Interpretation of the Structure and Phase Transitions in Nanocomposites Based on Modified Polyolefins and Technical Carbon

The results of the investigation of the thermomechanical characteristics of maleinized polyolefine-based nanocomposite materials with different carbon black content are presented. The high density polyethylene, low density polyethylene and polypropylene were used as polyolefins. Highly structured amorphous carbon black of the Printex XE 2B brand with a nanoparticle size of 20 nm, introduced into the composition of the polyolefin in an amount of 1.0–20 wt%, was used as technical carbon. To improve the compatibility of polyolefins with technical carbon, a compatibilizer was used – high-density polyethylene graft copolymer with 5-6 wt% maleic anhydride (PEMA) brand Exxelor PO1040 and polypropylene graft copolymer with 5-6 wt% maleic anhydride (PPMA) brand Exxelor PO1020. The compatibilizer was introduced into the composition of polyolefins in the amount of 2.0 wt%. An electron microscopic, derivatographic and X-ray diffraction analysis of nanocomposites with different technical carbon content was carried out. Thermomechanical studies were carried out on a Kanavets instrument. It was found that with an increase in the content of technical carbon within 1.0, 5.0, 10, 20 wt%, the regularity of change in the thermomechanical curves undergoes significant changes. At a technical carbon concentration of 10 and 20 wt%, an area as a plateau appears on the thermomechanical curves. The most thermally stable plateau appeared for nanocomposites based on maleized LDPE* and PP* with 20 wt% technical carbon content. New scientific approaches are presented for interpreting the discovered regularities, taking into account modern theoretical concepts of the supramolecular crystal structure of nanocomposites and the interfacial amorphous region.read more

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Najaf Kakhramanov, Khayala Allakhverdiyeva, Qalina Martynova, Fatima Mustafayeva, Yunis Kahramanli, Nazim Sadikhov, Azer Amirov

Enhanced Biosynthesis and Purification of Proteases from Bacillus sp. AI-5 by SmF: A Green Approach for Degradation of Peptide Bonds in Complex Proteins

Proteases are theprotein degrading commercial enzymes with considerable importance for many industrial applications such as paper, leather, food industries as well as used in detergent formulation, toxic waste removal, pharmaceutical and drilling for oil. The focus of the current study was to isolate the novel protease producing bacterial sp. from environment, to optimize the submerged fermentation parameters in order to design the best supportive media for maximum enzyme yield and to purify the enzyme to increase its utilization in various industries, most importantly the pharmaceutical industry.Five pure cultures were isolated from soil of coastal area, Karachi and the bacterial strain that was proved to be the most potent producer of protease was selected for research purposeand named as Bacillus sp AI-5 after series of morphological and biochemical tests. The fermentation conditions and media composition were optimized using the starter medium that was selected among the three previously reported media for protease production. It was found that protease production from Bacillus sp AI-5 reached to maximum when media was supplemented with 0.4 gm % casein as carbon source, the combination of 0.5 gm % yeast extract and 0.5 gm % peptone as nitrogen source and 0.05 gm CaCl₂ as inducer and stabilizer of proteases. The optimum pH and temperature for maximum production of protease were found to be pH 5 and 45 °C respectively after 24 hours of incubation. The protease of the Bacillus sp. AI-5 was purified to homogeneity by salt fractionation method using 60 gm % ammonium sulfate, dialysis and Sephadex G-100 Gel filtration chromatography. The specific activity of purified protease was found to be 322.25 U/mg with 13.80 fold purification as compared to crude enzyme. The purified enzyme gave a single band on Sodiumdodecyl sulfate Polyacrylamide gel electrophoresis (SDS-PAGE)corresponding to a molecular weight of 66 kDa.read more

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Aliya Riaz, Isma Idrees, Sana Ahmad, Ayesha Siddiquiand Shah Ali Ul Qader

Enantiomeric Separation by Capillary Electro chromatography with a Novel β-cyclodextrin-hyperbranched Carbosilane–silica Polymer Coating

A new type of β-cyclodextrin-modified hyperbranched carbosilane (β-CD@HBC) stationary phase was synthesized by combining hyperbranched carbosilane with the -OH group of β-cyclodextrin, and then the β-CD@HBC was used as astationary phase to fix it on the inner wall of capillary column, application in chiral drug separation. The chromatographic behaviour of the stationary phase was studied. The preliminary test results showed that the β-CD@HBC coated OT column has the ability to separate a variety of enantiomers, such as clenbuterol, ibuprofen, enrofloxacin, hlorpheniramine, isoproterenol hydrochloride, epinephrine, Phenylalanine, and Ketoprofen. The β-CD@HBC coated OT column has good repeatability and stability. The relative standard deviations (RSD) between runs, between days, and between columns were less than 1.5%, 1.86%, and 4.83%, respectively. This paper shows that hyperbranched polymers have great potential and advantages in the application of capillary electrochromatography for chiral separation.read more

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Xiangqing Yang and Yali Hang

Copper-DMEDA Catalyzed Carbon-Sulfur Bond Formation for the Derivatization of 5-(3,4,5-Trimethoxyphenyl)-1,3,4-oxadiazole-2-thiol

Sulfide linkage plays an important role not only in synthetic chemistry but also has vast applications in drug discovery as a pharmacologically active moiety. Transition metal-catalyzed thiolation is a challenging task as sulfur has a high affinity to bind with transition metal catalysts resulting in catalyst poisoning. Catalyst poisoning results in the inhibition of the reactivity and utility of the reactions. In the current work, a simple and facile method is developed to carry out S-arylation using hetero-aryl thiols and substituted aryl iodides. The reaction conditions were optimized using varied combinations of transition metal catalysts and ligands. The different copper sources included CuCl, CuI, and Cu(OAc)2 different bidentate nitrogen-based ligands including bipyridine, di-tert-butylbipyridine, DMEDA, and sarcosine. The optimized condition consists of CuI as the catalyst and DMEDA as a ligand. The reaction was found to be optimum for a range of aryl iodides in the presence highly basic oxadiazole ring. The coupled products were isolated in excellent yields and show excellent functional group tolerance bearing -NO2, -Cl, -OCF3 groups.read more

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Hassan Adrees, Zahra Begum, Haseen Ahmad, Rifhat Bibi, Sania Batool and Abbas Hassan

Comparison of Biological Activities and Bioactive Components of Seed, Leaf, and Blossom Parts of Camellia sinensis (L.) Kuntze and Commercial Black Tea

In this study, bioactive properties and GC-MS analyses of the Camellia sinensis (seed, leaf, and blossom parts) and commercial black tea extracts were compared. The total phenolic content (TPC) and antioxidant and antimicrobial activities of extracts were determined. The gas Chromatography-Mass Spectrometry (GC-MS) technique was used to identify the major bioactive compounds in extracts. The TPC and antioxidant activity values of the alcohol extract prepared from the leaf part of the C. sinensis are higher than the other extracts. There was a strong correlation between total phenolic content and antioxidant amount among the ethanol extracts of C. sinensis. In antimicrobial evaluation, the ethanol extracts showed more activity; the ethanolic extract of C. sinensis seeds was the most effective. GC-MS results indicated various organic compounds in the C. sinensis extracts, mainly saturated and unsaturated aromatic esters, aromatic alcohols, some cyclic structures, aromatic amine, and boranic esters with different therapeutic activities. The black tea extracts exhibited a more straightforward variety of bio components as aromatic esters and boranic ester. According to the obtained results, C. sinensis and black tea extracts would exert several beneficial effects by their biological activities thanks to the possible synergistic effect of chemical contents detected by GC-MS analysis. However, GC-MS results indicated that the black tea sample had much fewer bioconstituents than fresh C. sinensis plant samples.read more

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Ömer ERTÜRK, Elif ÇİL, Melek ÇOL AYVAZ and Emine BAĞDATLI