VOLUME 36, NO2, APR-2014
123
 
Removal of Direct Red 16 (Textile Dye) from Industrial Effluent by using Feldspar

Nadia Jamil, Saba Maqsood Khan, Naveed Ahsan, Jamil Anwar, Abdul Qadir, Mariyam Zameer and Umer Shafique

Dyes are one of the major categories of environmental pollutants. Unfortunately disposal of these hazardous chemical pollutants is usually done by throwing them in any nearby water channels. Physical adsorption is an efficient and cost effective technique to eliminate dyes from waste water. In present study Feldspar is used as adsorbent for the removal of Direct red 16 (textile dye). Different parameters like speed of shaking, adsorbent dosage, time of contact of two phases, pH and analyte concentration were optimized to get maximum adsorption capacity i.e. FTIR analysis of adsorbent was done to study the functional groups present on surface of adsorbent. Adsorption isotherms Langmuir and Fruendlich were investigated to evaluate the values of Q and K which were 5.30 mgg-1 and 1.25 mgg-1 respectively. Values of thermodynamic parameters ΔH (change in enthalpy), ΔS (change in entropy) and ΔG (change in Gibbs energy) were calculated. The results of adsorption indicate that physisorption is much favorable for adsorption of Direct Red 16 on feldspar. So, Feldspar was proven a good adsorbent and found to have good potential for removal of Direct Red 16 from waste water.
Pages(191)
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Morphology and Physicochemical Performance of Water-soluble Carboxymethyl Chitosan/Polyurethane Blend Film

Guo-Quan Zhu, Fa-Gang Wang, Chang-Hong Su, Qiao-Chun Gao and Yu-Ying Liu

A series of water-soluble carboxymethyl chitosan (CMCS)/polyurethane (PU) blend films with various CMCS/PU mole ratios were prepared by casting the polymer blend solution in the mixed solvents of dimethyl sulfoxide (DMSO) and water. Surface morphologies of CMCS/PU blend films were studied by scanning electron microscopy (SEM). Thermal, mechanical, and chemical properties of CMCS/PU blend films were investigated by thermogravimetric analysis (TGA), tensile tests, and contact angle tests. It was revealed that the introduction of PU could greatly affect the surface morphology and the performance of CMCS film.
Pages(198)
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Investigation the Physicochemical Properties and Stability of W/O Emulsion

Shahid Iqbal, Musa Kaleem Baloch, Gulzar Hameed, Wajid Rehman, Rubina Naz and Muhammad Akhlaq

The study aims to investigate the stability of W/O emulsions with respect to coalescence time. The various concentrations of water were dispersed in oil phase (soybean oil). The compositions of organic and aqueous phases were varied by adding emulsifier (Monoglyceride), sodium chloride and thickening agent (mango’s pulp). The technique employed for the mixing of two phases was homogenization. The Emulsion Stability Index (ESI), Viscosity changes, separation of organic and aqueous phases as a function of storage time have been studied. It has been found that monoglyceride increases the stability and decreases the emulsion stability index (ESI) and also decreases the viscosity changes with storage time while electrolytes and mango’s pulp encourage the coalescence process and enhance the instability of the system. On the other hand the system that contained all the organic and aqueous ingredients showed high stability.
Pages(204)
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Critical Intermolecular Forces: A New Physical Insight for the Formation of Wormlike Micelles

Rabah Ali Khalil and Fahad Jumaah Hammad

Up to present date, no obvious and reasonable theoretical approach interpreting the formation of worm- or thread-like micelles together with the accompanying sharp change in the rheological properties. Consequently, systems of binary and ternary mixtures of 3 wt% anionic, cationic and nonionic surfactants have been investigated at different temperatures. The mixture of anionic [sodium dodecylsulfate (SDS)] and cationic [cetyltrimethylammonium bromide (CTAB)] surfactants exhibits a remarkable high viscosity peak at weight ratio of 80/20 CTAB/SDS. No wormlike micelles have been detected for binary mixtures of anionic- nonionic (Triton-X 100) nor for ternary mixtures of SDS/CTAB/Triton-X 100 surfactants. Approximate relations have been introduced for evaluating the thermodynamic change from spherical to one-dimensional supramolecular aggregate. Conductivity measurements have been performed for supporting the present investigation. The results reveal a new physical insight called Critical Intermolecular Forces (CIF), which is responsible for the transition phenomenon from three to one-dimensional shape of aggregate. It has been concluded that the suggested theory of CIF plays as a powerful tool in understanding not only the transition state towards wormlike micelles together with the associated significant increasing in solution viscosity, but also for helping researchers who are interested in exploring any kind of new wormlike systems.
Pages(211)
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Self Assemble Behavior of Poly (Oxybutylene-Oxyethylene) (BmEnBm) Triblock Copolymer in Solution

Muhammad Siddiq, Imad-Ud-Din, Mohsan Nawaz, Wajid Rehman, Iram Bibi, Abbas Khan and Bakhtiar Muhammad

Amphiphilic block copolymer of two triblock copolymer B17E122B17 and B24E450B24, B denoting OCH2CH(C2H5), E denoting OCH2CH2, and the subscripts denoting number-average chain lengths were investigated in solution and characterized through surface tension, viscosity, and dynamic light scattering. Critical micelle concentration, (CMC) determined from the surface tension data was found to decrease with the increase of temperature as well as with the increase in hydrophobic block length for both the copolymers investigated. Standard free energy of micellization (ΔGmic) value was found to decrease in the range (-18 to -23KJmol-1) with the increase of temperature. Standard entropy factor of micellization (TΔSmic) also increased in the range (51.04 to 56.33 KJmol-1) with the rise in temperature, while enthalpy (ΔHmic) is temperature independent. Viscosity and Dynamic light scattering were used to determine intermicellar interactions and to characterize the micelles in dilute solutions respectively. The data obtained demonstrated the formation of compact micelles at low temperatures and of elongated at higher temperatures.
Pages(221)
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Dehydration Kinetics of Tincalconite from Thermogravimetric Data

Fatih Sevim, Hilal Küçükarslan, Fatih Demir, Hayrettin Eroglu and Mehmet Aktan

Kinetic parameters of tincalconite during thermal decomposition were explored with TGA data. Coats-Redfern and Suzuki methods were implemented for the kinetics analysis. Decomposition kinetics of tincalconite occurred in two steps and both suitably fit a first-order kinetic model. Activation energy and frequency factor were observed as 149.17 kJ.mol−1 and 1.2x1016 min−1 for region I, and 5.45 kJ.mol-1 and 5.23x108 min-1 for region II, respectively with the Coats-Redfern method. Activation energy and frequency factor were observed as 60.95 kJ.mol-1 and 67.21x105 min-1, respectively for the Suzuki method.
Pages(227)
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Investigation of Adsorption Thermodynamics on Removal of Reactive Blue 19 onto Activated Carbon under Ultrasonic Irradiation

Enes Şayan, Osman Nuri Ata and Meryem Esra Edecan

Adsorption thermodynamics of reactive blue 19, which is commonly used in textile industry, has been studied onto activated carbon. The adsorption experiments have been carried out using combined ultrasound/activated carbon. The equilibrium adsorption data were analyzed by using the Langmuir and Freundlich isotherms. The equilibrium parameter, RL indicates that adsorption of reactive blue 19 onto activated carbon is favorable for all the concentrations studied. Thermodynamics parameters, ΔGads, ΔHads, ΔSads have also been calculated from the slope and intercept of the plot of ln Kd vs. 1/T. The thermodynamic parameters studied show that the adsorption of Reactive Blue 19 onto activated carbon is endothermic.
Pages(232)
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Properties Study of Poly(L-lactic acid) Film Modified by Blending with Flexible Poly(tetramethylene glycol)

Guo-Quan Zhu, Fa-Gang Wang, Ke-Jing Xu, Qiao-Chun Gao and Yu-Ying Liu

A series of poly(L-lactic acid)/poly(tetramethylene glycol) (PLLA/PTMG) blend films were prepared by casting the polymer blend solution in chloroform. Surface morphologies of the PLLA/PTMG blend films were investigated by scanning electron microscopy (SEM). Thermal, mechanical, and chemical properties of PLLA/PTMG blend films were studied by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), tensile tests, and surface contact angle tests. It was revealed that the introduction of flexible PTMG could markedly modify the properties of the PLLA films.
Pages(239)
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Kinetics of Citrulus Colocynthis Oil Transesterification

Yasir Ali Elsheikh, Faheem Hassan Akhtar, and Ayyaz Muhammad

Citrulus Colocynthis oil and methanol was transesterified in the presence of NaOH as catalyst at five investigated temperatures, whereas the other reaction parameters were kept constant. This study was led to explore the kinetics of temperature and the effect of NaOH concentration on the transesterification reaction, and to assess the reaction constants and activation energies of the three forward reactions. The highest biodiesel yield of 97.8% was obtained at the optimum temperature of 60 ºC. The reactions of triglycerides (TG), diglycerides (DG) and monoglycerides (MG) with methanol to produce methyl ester (ME) in the forward reactions appeared to be second order up to 60 min of reaction time. The kinetic constants for TG, DG and MG were found to be in the consecutive of MG>DG>TG. Activation energies were 14.1 kcal/mol, 10.5 kcal/mol, and 6.34 kcal/mol for the TG, DG, and MG hydrolysis reactions respectively.
Pages(243)
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Electrospinning Synthesis of MgO Nanofibers and Properties of Uranium (VI)-sorption

Bo Ren

Magnesium oxide (MgO) nanofibers were prepared by electrospinning process. The characterizations of the adsorbent were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The obtained nanofibers could be used as adsorbents for the removal of Uranium (VI). The maximum adsorption occurred at pH 6, the equilibrium adsorption amount was about 90mg/g, and the equilibrium time was 120min.
Pages(250)
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