VOLUME 36, NO4, AUG-2014
123
 
Optical Resolution of Phenylalanine Using D-Phe-Imprinted Poly(acrylic acid-co-acrylonitrile) Membrane—pH Effect on performance

Noaman Ul-Haq and Joong Kon Park

The molecular imprinting technique was used for chiral resolution of phenylalanine (Phe). The template was introduced during polymerization and removed after polymerization by leaving imprinted cavities in the polymer matrix correspondence to template. The D-Phe imprinted membrane selectively adsorbed D-Phe, facilitated permeation of D-Phe and rejected L-Phe. These results are evidence of the availability of the chiral environment in the membrane. The membrane was found to be pH sensitive, with 0.30 rejection selectivity, 2.40 adsorption selectivity and 2.03 permselectivity being achieved at pH-2. FT-IR and FE-SEM analyses revealed that the membrane was nano-porous and very thin.
Pages(561)
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Electro-Oxidation Performance and Photo-Structural Characterization of Induced Natural Additive on Chloride Electrolyte Thin film Coated Steel

Fayomi Ojo Sunday, Abimbola Patricia Popoola and Vincent Tau

Improvement of engineering materials to avert corrosion, toxicity and to enhance the appealing value of steel has led to an enlarged interest in electro-deposition industries. The effect of solanum tuberosum (ST) extracted juice and Al dispersed particulate for Zn bath electrodeposition on mild steel from aqueous chloride solutions was investigated. The electrodeposition was carried out by adding Al particles and ST to a zinc-containing bath. Corrosion tests were performed at room temperature in 3.65 mol dm-3 NaCl solutions by cyclic potentiodynamic and open circuit polarization. Characterizations of the electrodeposited coatings were carried out using scanning electron microscopy equipped with energy dispersive spectrometer (SEM/EDS) and X-ray analysis diffraction (XRD). The experimental results show that significant change in the presence of the additives influences the crystal orientations, resulting into precipitation of ZnAl3.Si and Zn2Al5 phases. The change in structure can also be linked to a robust blocking effect of the cationic surfactant of solanum tuberosum juice and Al dispatched oxide films which might influence nuclei replenishment and impact smaller grain size.
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Kinetics and Mechanism of Reduction of Iron(III) Kojic Acid Complex by Hydroquinone and L-Cysteine

Atim Sunday Johnson, Zahid Hussain, Muhammad Perviaz, Syed Arif Kazmi, Ededet Akpan Eno and Offiong E. Offiong

The effect of pH on the kinetics of reduction of iron(III) kojic acid complex by hydroquinone (H2Q) and L-cysteine (L-Cys) was studied in the pH range of 2.34 - 4.03 for H2Q and 3.04 – 5.5 for L-cysteine at ionic strength of 0.5 M and at 35oC. The pseudo-first order rate constants for the reduction of Fe(KA)3 by L-cysteine and hydroquinone increase linearly with increasing reductant concentration, indicating first-order kinetics in reductant concentration. However, whereas the rate of reduction by H2Q increases with increasing pH, an opposite trend was observed in the case of reduction by L-cysteine. Plausible rate laws and mechanisms have been proposed in line with these observations. Activation parameters (∆H# and ∆S#) were evaluated for the reduction of iron (III) kojic acid complex by cysteine and the values obtained are 35.25 kJmol-1, -141.4 JK-1mol-1 and 28.14 kJmol-1 , 161.2 JK-1mol-1 for pH 4.5 and 3.52 respectively.
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Study on Combined Effects of Acidification and Sonication on Selected Quality Attributes of Carrot Juice during Storage

Saqib Jabbar, Muhammad Abid, Bing Hu, Malik Muhammad Hashim, Sher Ali, Tao Wu, Shicheng Lei, Minhao Xie and Xiaonxiong Zeng

This study evaluated the combined effects of acid blanching and sonication treatments on selected quality parameters of carrot juice stored at 4 ºC for 18 days. Carrots were blanched in acidified water (40g/L citric acid) at 100 ºC for 4 min and the juice was then extracted. Sonication of the juice was done at an amplitude level of 70% and a frequency of 20 kHz for 2 min at 15 ºC, keeping the pulse duration of 5 Sec on and 5 Sec off. As results, the combined treatment of acidification and sonication of carrot juice showed a significant decrease in pH and increase (P < 0.05) in acidity which remained stable during storage period. No significant changes were observed in °Brix. Color values (L*, a*, b*) and non enzymatic browning (NEB) influenced significantly in acidified and sonicated carrot juice during storage period. Maximum stability of total phenol, total antioxidant capacity, cloud value and ascorbic acid were also observed in the combined treatment of acidification and sonication. The findings of this study indicated that the combined treatments of acidification and sonication may successfully be utilized for the production of high quality carrot juice with improved stability of total phenol, total antioxidant capacity, cloud value and ascorbic acid during 18 days of storage.
Pages(582)
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Investigation of Bifunctional Ester Additives for Methanol-Gasoline System

Jie Zhang, Changchun Yang, Ying Tang, Qiulong Du, Na Song and Zhifang Zhang

To explore new and multifunctional additives for methanol-gasoline, tartaric ester were synthesized and screened as phase stabilizer and saturation vapor pressure depressor for methanol-gasoline. The effect of the esters’ structure on the efficiency was discussed. The results show that the stabilities of the blends depend on the length of the glycolic esters’ alkoxy group. In addition, the tartaric esters also can depress the saturation vapor pressure of methanol-gasoline effectively in M15. Effect of the structure on the efficiency was also discussed.
Pages(590)
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Performance Characteristics of Industrial waste-N330, N550 and N660 Carbon Black Hybrid Natural Rubber Composites

Khalil Ahmed, Khalid Mahmood and Sheraz Shafiq

In this research work, natural rubber (NR) hybrid composite was prepared by incorporating industrial waste such as marble sludge with three different types of carbon black (CBdt) to be precise as CBN330, CBN550 and CBN660. Samples were mixed on two roll mill and vulcanized at 150° C. The effects on the curing characteristics, mechanical and swelling properties of NR hybrid composites of CBdt with MS were evaluated in CBdt and hybrid combinations of MS/CBdt. It was found that gradual increment of CBdt in MS/CBdt hybrid composite decreased the scorch and cure times, however the minimum and maximum torques increased with increasing CBdt in particular hybrid composite. The overall mechanical properties tended to increase, however the % elongation at break, resilience and abrasion loss decreased with increasing CBdt. The swelling ratio has also been observed to be decreasing and cross link density and shear modulus increasing with CBdt incorporation.
Pages(594)
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Optimization of Dissolution of Ulexite in Phosphate Acid Solutions

Tuba Hatice Doğan and Ahmet Yartaşı

The Taguchi optimization method was used to determine optimum conditions for the dissolution of ulexite in phosphate acid solutions. Reaction temperature, solid-to-liquid ratio, phosphate acid concentration, reaction time, particle size and stirring speed were chosen as parameters. The optimum conditions for these parameters were found to be 60oC, 0.15g.mL-1, 0.70M, (-850+452) μm, 30 minutes and 200rpm, respectively. Under these conditions, the dissolution percentage of ulexite in phosphate acid solution was 100. Reaction products were found to be boric acid, sodium dihydrogen phosphate and calcium dihydrogen phosphate.
Pages(601)
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Effect of Template on Chiral Separation of Phenylalanine using Molecularly Imprinted Membrane in Aqueous Medium

Noaman Ul-Haq and Joong Kon Park

Wet phase inversion method was used to prepare L-Phenylalanine (L-Phe) and D-Phenylalanine (D-Phe) imprinted poly [(acrylonitrile)-co-(acrylic acid)] membranes for chiral separation. Ultrafiltration experiments were conducted to evaluate the chiral separation ability of the prepared membrane towards racemate aqueous solution of Phenylalanine. The continuous permselectivity was observed by novel membrane. The chiral resolution ability of L-Phe imprinted membrane was much better than that of D-Phe. It was observed that both membranes simultaneously, selectively reject, selectively adsorbed and selectively permeate solute. The achieved adsorption selectivities of L-Phe imprinted membrane [Ads]L and D-Phe imprinted membrane [Ads]D were 2.6 and 2.40 respectively. Permselectivity of L-Phe imprinted membrane [Perm]L was 2.56 while D-Phe imprinted membrane’s permselectivity [Perm]D was 2.03. The rejection selectivities of L-Phe and D-Phe imprinted membranes were [Rej]L=0.32 and [Rej]D =0.28 respectively.
Pages(606)
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Biosorption of Eriochrome Black T and Astrazon FGGL blue using Almond and Cotton seed Oil Cake Biomass in a Batch Mode

Yusra Safa

In the present research study, the biosorption of Eriochrome Black T (EBT) and Astrazon FGGL blue (A-FGGL) onto novel biomasses Almond (Prunus dulcis) oil cake and Cotton seed oil cake respectively was investigated in the batch mode using different process parameters like pH, particle size, biosorbent dose, initial dye concentration, contact time and temperature. Maximum biosorption capacity was observed at pH 3 for EBT onto almond oil cake and pH2 for Astrazon FGGL blue onto cotton seed oil cake.The biosorption capacity was efficient at the smallest particle size of biosorbent. The amount of dye sorbed (mg/g) decreased with the decrease in biosorbent dose and increased with increase in initial dye concentration and temperature. Optimum contact time for equilibrium to achieve was found to be 120 and 180 minutes for EBT and A-FGGL blue, respectively. The Langmuir isotherm model was best fitted to experimental data. The biosorption followed the pseudo-second order kinetic model suggesting a chemisorption mechanism. The positive value of H° showed the endothermic nature of the process. In this research, the influence of electrolytes, heavy metals and surfactants on the removal of dyes was also examined.
Pages(614)
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Recovery of Alumina from Khushab Bauxite by Leaching with Sulphuric Acid and Removal of Iron Impurity by Ethanol

Muhammad Tariq, Muhammad Mansoor Iqbal, Abdul Aziz, Muhammad Shafiq, Muhammad Sajid and Bashir Mohammad

Bauxite is heterogeneous material principally composed of aluminum oxide minerals and found in all continents. It is being used in chemical, cement, refractory, abrasive, fertilizer, steel and other industries. In order to extract the alumina, the calcined samples of bauxite of Khushab area were ground to -710 μm. Sulphuric acid of purity 40% was used as leaching agent and slurry of pulp density 14% was prepared by dissolving 60 ml acid in 20 gm sample. The leaching was carried out at 90°C for 2 hours. The iron impurity was removed by ethanol of purity 68%. The drying, dehydration and desulphurization temperatures were kept 105°C, 450°C and 850°C respectively in all the stages of the process. Alumina recoveries from four samples of Sultan Mehdhi, Chamil More, Niaz Mine and Nadi locations were 20.8%, 9.81%, 15.47% and 7.78% respectively. Iron was almost completely removed as the analysis shows that the Fe2O3 removal was from 97.8% to 99.6%. It is concluded that leaching efficiency was quite encouraging except Nadi ore sample. However the iron free alumina recoveries were low as the analysis of Fe2O3 processed residue shows that it contains 72.72% to 92.94% of leached alumina in all the four experiments.
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