VOLUME 40, NO3, JUNE-2018

Polymeric Antioxidant from Polyacrylic Acid

Acrylic acid was polymerized and modified with some acids such as salicylic acid, benzalthiobarbituric acid and some amines such as aniline and α-naphthylamine. Modified polyacrylic acids (PA) were characterized with FT-IR spectroscopy and thermal analysis and their ability was tested to be antioxidants for PVC which contains sensitive terminal double bonds toward oxidative conditions. The extent of PVC discoloration is considered to follow up the degrading thermal oxidation. All the investigated polyacrylic acid derivatives showed ability as polymeric antioxidants better than the unmodified especially polyacrylylbenzalthiobarbituric acid. The results obtained are justified and discussed.read more

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Magdy Y. Abdelaal, Mohammad S.I. Makki and Tariq R.A. Sobahi

Quantum Mechanical Study on the Mechanistic, Energetic and Structural Aspects of Adsorption of 2-methoxyestradiol Drug on Functionalized Carbon Nanotube

Using density functional theory, noncovalent interactions and two mechanisms of covalent functionalization of drug 2-methoxyestradiol with functionalized carbon nanotube (CNT) have been investigated. Quantum molecular descriptors of noncovalent configurations were studied. It was specified that binding of drug 2-methoxyestradiol with functionalized CNT is thermodynamically suitable. COOH functionalized CNT (NTCOOH) has more binding energy than COCl functionalized CNT (NTCOCl) and can act as a favorable system for 2-methoxyestradiol drug delivery within biological and chemical systems (noncovalent). NTCOOH and NTCOCl can bond to the OH group of 2-methoxyestradiol through OH (COOH mechanism) and Cl (COCl mechanism) groups, respectively. The activation energies of two pathways were calculated and compared with each other. The activation energy related to COOH mechanism is higher than that related to COCl mechanism and therefore COCl mechanism is suitable for covalent functionalization. These results could be generalized to other similar drugs.read more

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Mohammad Arab, Ali Morsali, Mohammad M. Heravi, and S. Ali Beyramabadi

Production of Biodiesel by Ultrasonic-Assisted Methanolysis of Cantaloupe Seed Oil and its Optimization by Taguchi Method

Present work is an effort of an agrowaste valorization, whereby the cantaloupe seed residue has been proposed as a potential feedstock for biodiesel production. Oil, from dried cantaloupe seeds, was extracted using n-hexane as extraction solvent in three batches. Oil content was found to be 42.8% (w/w) of seed residue. Physicochemical characteristics of oil including density (0.887 g/mL), kinematic viscosity (34.5 cSt), refractive index (1.48), free fatty acid content (0.78%), iodine value (128 g I2/100 g oil) and saponification value (220 mg NaOH/g), were determined using standard IUPAC methods. Fatty acid composition of both oil/ biodiesel was determined by GC-FID and confirmed by 1H NMR spectra of methyl esters. Ultrasonic-assisted transesterification of cantaloupe seed oil was carried out using KOH as catalyst and optimization of process parameters was done using Taguchi method. Optimized parameters included molar ratio of alcohol to oil (9:1), amount of catalyst (1% w/w of oil) and reaction time (60 min). Major fuel properties of synthesized biodiesel including cetane index, flash point, cloud point, pour point, density, kinematic viscosity, total ash and distillation range were determined according to standard ASTM methods. The values were found to be within ASTM D6751 specifications for biodiesel. On the basis of findings of this study, cantaloupe seed oil may be ranked as a viable feedstock for biodiesel production.read more

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Taslim Akhtar, Muhammad Ilyas Tariq, Shahid Iqbal, Nargis Sultana, and Kim Ei Chan

Optimization of Boric Acid Extraction From Colemanite With An Environmentally Friendly Process By Using The Taguchi Method

Boric acid, one of the boron products, is obtained from colemanite sulfuric acid process in some countries. In this process, sulfur dioxide was used instead of sulfuric acid to obtain H3BO3. The purpose of this research is to produce boric acid from a cheaper and more environmentally friendly process. In this research where H3BO3 was obtained, optimization of the dissolution of the original colemanite containing clay in SO2-saturated water was investigated using the "Taguchi Method". In experiments, solid-liquid ratio, mixing speed, reaction temperature, reaction time and particle size were selected as parameters. Optimization studies were carried out in two stages. According to the results obtained in the first stage, the best value for the mixing speed was found to be 300 rpm and the mixing speed is found to have little effect. Therefore, the mixing speed was kept constant in the second stage. According to the second design, the optimum conditions were found at 50oC for reaction temperature, -212+150 μm for particle size, 0.25 g/mL for solid liquid ratio, and the B2O3 passing through the solution under these conditions was 98.5%.read more

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Özkan Küçük and 2Haluk Korucu

Removal of Organic Pollutants by Using Surfactant Modified Bentonite

Naturally abundant bentonite clay minerals have high cation exchange capacity (80–120 meq/g), greater surface area, enhanced swelling properties with micro and meso-porosity. However, their hydrophilic surface limits their adsorption ability. In the present study, bentonite clay (BT) was modified with a cationic surfactant by using cation exchange reaction to modify its surface from hydrophilic to hydrophobic; thus making it a better adsorbent for the removal of pollutants from contaminated water. The modified clay was characterized through fourier transform infrared spectroscopy, and thermo gravimetric analysis. It was used as an adsorbent for the removal of methyl orange and deltamethrin from aqueous solutions. The results showed that modified bentonite has strong tendency to remove organic pollutants from water. About 97% removal of methyl orange was observed with surfactant modified bentonite in contrast to only 56% removal with unmodified bentonite. Similarly, modified bentonite removed up to 98% deltamethrin as compared to only 47% removal with unmodified bentonite. Kinetic study of both experiments showed that the absorption process follows a pseudo second order equation.read more

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Sana Ahmad and Khizra Yasin

Adsorption Equilibrium and Thermodynamics of Diatomite (Çaldiran/Van) OnSome Textile Dyes

Together with increasing world population, developing technology and rapid industrialization process bring about environmental pollution. Nowadays, cleaning environment from industrial wastes and pollutants is of utmost importance. Some organic materials, produced by the majority of textile waste, cause environmental pollution. Many dyestuffs, which are hazardous for environment, can be released to environment by industrial organizations without having any precaution. Textile dyestuffs, being above certain concentrations, can cause poisoning of aquatic organisms. Dyestuffs can be classified as following: Anionic: Direct, acid and reactive dyes Cationic: Basic dyes Nonionic: Disperse dyes It can be said that most problematic group of dyes used in the textile industry is the group of reactive dyes. Analyzing performed studies shows that these views are supported. Today, adsorption techniques are gaining ground due to efficiency in removal of too stable pollutants. Adsorption is, economically, a reasonable method and we can say that it provides formation of high quality products. With the development of industry search for materials, to be used as adsorbent for removal of factory wastes and water-soluable dyestuffs from water, accelerates. In our study, from natural adsorbents diatomite(Çaldıran/VAN) is used as an adsorbent material. The removal of natural red and basic blue from aqueous solution using diatomite, was investigated with respect to the adsorbent dose (0,02 g), initial concentration (20-140 mg/L), temperature (between 25 and 450C), on batch adsorption were studied as a function of contact time. The lineer Langmuir, Freundlich and Temkin adsorption equations were applied to describe the equilibrium isotherms. In addition, the pseudo-first-order, pseudo-second-order and intraparticle diffusion models were used to determine the kinetic data. The experimental data were well fitted by the pseudo-second-order kinetic model. Thermodynamic parameters such as the enthalpy (ΔH0), Gibbs free energy (ΔG0) and entropy (ΔS0) shoved spontaneous and endothermic in nature of adsorption for both of adsorbents.read more

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Salih Alkan, Meliha Çalişkan, İlhan Irende and Ali Rıza Kul

Preparation of 4PNPAN Dyed Poly (vinyl butyral) Copolymer Films for Dosimetric Applications

Poly (vinyl butyral co-poly vinyl alcohol co-vinyl acetate) (PVB-co-PVA/PVAC) combined with 4-(p-nitrophenyl-azo)-1-naphthol dye has been examined a promised dosimeter suitable for high dose ranges. The prepared films have yellow color. This color undergoes color bleaching upon irradiation with gamma rays. Different concentrations were prepared to obtain the suitable dosimeter in the dose range from 3 to 200kGy depending on the dye concentration. Chloral hydrate was then added in different concentrations, as a result the bleaching reaction expedites and in accordance the dose range diminishes to be 35kGy. The effect of chloral hydrate as well as dye concentration on response curve was studied. The radiation efficiency (G-value) was estimated for all the prepared films. Influence of relative humidity during irradiation was estimated as well as stability before and after irradiation.read more

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Sayeda Elewa Eid, Seif Ebraheem and Nehad Magdy

Electro catalytic Oxidation of Reactive Orange 122 in Wastewater by Using Three-Dimensional Electrochemical Reactor (3DER)

In the present study, electrocatalytic treatment of Orange 122 in wastewater was studied by using a three-dimensional electrochemical reactor (3DER). Firstly, TiO2/AC, V2O5/TiO2/AC and WO3/TiO2/AC (over activated carbon) catalysts were prepared by a sol–gel method in aqueous solution. The process optimisation was carried out by investigating the effects of time, voltage, suspension’s pH, dye concentration, the amount of supporting electrolyte (NaCl) and the type of catalysts. Optimum values for these parameters were found as 120 min., 15 V, 6.5, 250 mgL-1 and 800 mgL-1 respectively. The results obtained show that after 30 minutes only 30% colour was removed in the absence of activated carbon and this value increased to 60% in the presence of activated carbon. However, the percentage removal increased to 98% in the presence of all three catalytic materials under the same experimental conditions. In addition, for all three catalysts, the pseudo-first-order rate constants were obtained and the values were found to be between 1.12  10-2 min-1 and 3.97  10-2 min-1. The high removal efficiency of this system is attributed to the synergistic combination of adsorption, electrocatalytic and electrochemical oxidations occurring simultaneously during the oxidation process.read more

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Mehmet Uğurlu, Ali Imran Vaizoğullar, Ilteriş Yilmaz, Müslih Günbeldek, Abdul J. Chaudhary

MeOH Enhanced Aquathermolysis of Heavy Oil Catalyzed by Hydroxamic Acid-Ni( Complex at Low Temperature

To develop effective water-soluble catalysts for aquathermolysis of heavy oil, in this paper, a series of complex was synthesized using phenyl hydroxamic acid and metallic chloride. The Ni(II) complex was characterized, and all the complexes were screened in aquathermolysis of heavy oil. The effects of water content and Ni(II) complex concentration on aquathermolysis were investigated. The effect of adding methanol as a reactant was examined and interpreted. With the catalyst and methanol, the reaction occurred at temperatures as low as 180℃. The viscosity of the product was also substantially reduced by the decomposition of the large hydrocarbon molecules.read more

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Zhe Shen, Zhiyu Huang, Yongfei Li, Xuefan Gu, Bianqin Li, Chentun Qu, Hua Song

A Validated HPLC-PDA Method for Simultaneous Quantitation of Four Oral Antidiabetic Drugs and Application to Pharmaceutical Preparations

A simple, rapid, and sensitive HPLC-PDA method has been developed for the simultaneous separation and estimation of metformin (MET), sitagliptin (SIT), glipizide (GPZ), and glibenclamide (GBN). The proposed method utilized Bondapak™ C18 (3.9×150 mm, 10 μm) column and the separation has been achieved within 10 min, with mobile phase consisted of methanol: phosphate buffer 0.05 M (60:40, v/v) adjusted to pH 5, delivered at a flow rate of 0.8 mL/min. Photodiode array detector was used to detect drugs at 260 nm. The developed method was validated according to the ICH guidelines. The method was linear over the range of 0.5-100, 0.5-10, 0.005-10, and 0.5-10 μg/mL for MET, SIT, GPZ, and GBN, respectively, with excellent correlation coefficients (r ≥ 0.9976). Intra-day and inter-day RSD values were ≤ 2.6. The recoveries of drugs from their tablets ranged from 97-103%. The proposed method was successfully applied to the analysis of MET, SIT, GPZ, and GBN in their tablets, and it is suitable for the rapid quantitation of these drugs in single or combined dosage forms.read more

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Mona AlShehri, Nourah Al Zoman, Hend AlHarbi, Kholod AlSulaihim and Faten AlOdaib