VOLUME 40, NO2, APR-2018

Photophysical Properties and Orbital Energy Calculation in Diketopyrrolopyrrole Based Conjugated Polyelectrolytes

Theoretical calculation study of two alternating conjugated polyelectrolytes, named SDPP-PPV and SDPP-PPE, constituted of 1,4-diketo-2,5-bis(4-sulfonylbutyl)- 3,6-bis(4-bromophenyl) pyrrolo[3,4-c]pyrrole (SDPP) with 2,5-diethoxy-1,4-phenylenevinylene (DVB) or 2,5-diethoxy-1,4-phenyleneethynylene (DEB) were carried out with Gaussian 09 software. The absorption spectral study shows that SDPP-PPV and SDPP-PPE have broad coverage of visible spectra and considerable red shift compared with water-soluble poly(p-phenylenevinylene)s (PPVs) and poly(p-phenyleneethynylene)s (PPEs). The TD-DFT calculation results show that LUMO of the polymers can be significantly reduced and the HOMO-LUMO gap can be changed by introducing DPP into the backbone. Theoretical study indicates that introduction of electro-deficient unit DPP in the polymer main chain can optimize the band structure of traditional PPV and PPE. The improved optical properties and excellent water solubility of these two novel DPP-based conjugated polyelectrolytes allow them to be promising materials in optoelectronic applications.read more

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Kuan Liu, Lei Xu, DaQi Liu, Li Ping Liu, Yi feng Ni and LiuBin Zhao

Controllable Tuning Various Ratios of ZnO Materials Polar Facets in Dimethylacetamide Media and their Kinetic Photocatalytic Activity

Controllable ZnO materials with different morphologies were synthesized via a simple solvothermal method in dimethylacetamide (DMAc) media. The significance of the synthetic strategy is the generation of exotic structures without using any templates/structure directing agents and successful realization of different morphologies. Detailed investigation revealed that the size and shape of ZnO materials can be conveniently tailored by systematically exercising control on the choice of contents of DMAc. The optical properties of the as-prepared ZnO materials were investigated by room temperature photoluminescence. Photodegradation of phenol was used as a model reaction to test the photocatalytic activity of the ZnO products. The morphology-dependent photocatalytic performances in the degradation of phenol under UV light illumination were observed, in which the ZnO spherical nanoparticles exhibit the highest activity. The kinetic behavior of a photocatalytic reaction can be described by a pseudo-first order model. The efficiency of degradation of the as-prepared ZnO spherical nanoparticles structures was more than twice times faster than that of using ZnO rods under the UV light irradiation. Moreover, the as-prepared products exhibited high photostability, and degradation efficiency could be slightly decreased even after being used three cycles. The possible mechanism for the difference photocatalytic activity of the as-prepared ZnO structures was also discussed.read more

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Weiliang Feng, Min Tao and Pei Huang

Liquid-Liquid Extraction of Uranium from Nitric Acid Solution Using N, N-Di(2-ethyl- hexyl) hexanamide (DOHA) in Dodecane as Extractant

This work describes the liquid-liquid extraction of uranium (U) from 3 mole L-1 nitric acid media by N, N-di(2-ethyl hexyl) hexanamide (DOHA) in dodecane and subsequent determination of uranium using arsenazo III as a chromogenic reagent. Different factors (nitric acid, DOHA, metal ion concentration, salting out effect, temperature and shaking time) affecting the extraction /stripping process, were investigated. The investigation showed that the extraction is independent of the conc. of metal ions in the range of 5 to 300 µg mL-1 and inversely dependent upon the temperature. The desired species so extracted were found to have a stoichiometric composition as UO2(NO3)2.DOHA and UO2(NO3)2.2DOHA at lower and higher concentration of extractant respectively. Uranium could be stripped back from organic phase by using 0.1 mole L-1 ammonium hydroxide (NH4OH) and the extraction was found to be quantitative.read more

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Muhammad Hafeez, Rashida Fiaz, Muhammad Naeem Ahmed, Srosh Fazil, Rizwan Hayder, Akbar Ali and Abdul Majeed Khan

Application of Acid Dyes on Silk Fabric and Fastness Properties Part II

Synthesis of acid dyes was carried out by reacting diazotized substituted aryl amines and substituted naphthalene sulfonic acid as coupling component. Structural properties were studied by UV-visible spectroscopy, IR spectroscopy, 1H-NMR spectroscopy, MALDI-TOF mass spectrometric analysis and elemental analysis. Application of dyes was carried out on silk fabric and their fastness to light, washing, perspiration, and crocking was determined. The results revealed that the synthesized dyes are efficient for dyeing silk fabric which is evident from their excellent fixation, binding stability and fastness properties.read more

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Zeeshan Akhtar, Syed Imran Ali, Muhammad Farooq, Salman Zubair, Rasheeda Parveen, Khalid M. Khan

Preparation and Characterization of PEG/PVP blend, with Sepiolite Clay as Compatibilizer

In this work, blend of poly(ethylene glycol) and poly(vinyl pyrrolidone) were prepared. The prepared blend was then reinforced with the inorganic sepiolite clay (SC). All samples were prepared through solvent casting technique. The end-product (nanocomposites) was characterized for thermal stability, morphology, structure as well as the developed interactions among the ingredients. The x-ray diffraction data verified well intercalation and exfoliation of the clay in the polymer matrix. The compatibility and synergistic effects of sepiolite on the properties of PEG/PVP blend were deduced from the FTIR signals. The corresponding peaks shift from lower to higher frequency. The elemental composition of the nanocomposite was determined by energy dispersive X-ray (EDX). The obtained data reflects that addition of SC have synergetic effect on the properties of the polymer blends.read more

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Mohsan Nawaz, Ali Bahader, Sad Ullah Mir, Zia Ur Rehman, Masroor Ahmed Bangash, Hameedullah and Sidra Shaoor

Remediation of Cadmium Ions from Aqueous Media through Chemically Modified Saccharum arundinaceum: Prediction through Modeling Techniques

Adsorption is a cost effective and green technology for the removal of hazardous chemicals from aqueous media. In current work, remediation of cadmium ions from aqueous media is performed by employing chemically modified Saccharum arundinaceum. Sorbent was pretreated with acid and base, separately, to check the effect of these chemicals on its adsorption potential and base treated sorbent was selected for further analysis, due to its higher sorption potential (97.5%) for Cd2+. Characterization of sorbent was carried out by recording FTIR spectra for determination of functional groups and SEM for evaluation of surface morphology. FTIR spectra reflect suitability of sorbent material for removal of Cd2+ due to presence of abundant –OH groups on sorbent surface, which may develop strong binding with sorbate. SEM results exhibited presence of cylindrical cavities on sorbent surface, endorsing viability of sorbent for the removal of Cd2+. 24 full factorial design (FFD) was employed to optimize the experimental conditions. Experimental results of adsorption process were compared with the predicted results; obtained by first-order model of FFD and Artificial Neural Network (ANN). In FFD, all the possible combinations were used and predicted model was generated for application on experimental setup. Similarly, ANN was used to obtain predicted response by multi-layer perceptron (MLP) method. Predictive analysis, carried out by both the modeling techniques, yielded comparable results, i.e. FFD (0.9852) and ANN (0.9788); revealing good prediction ability of both the modeling techniques.read more

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Fozia Batool, Shahid Iqbal, Jamshed Akbar and Sobia Noreen

Auger Analysis of Surface Films formed on the Surface of 18Ni350 Steel during Maraging

18Ni350 Maraging steel samples were martensite aged (maraged) at 480 oC for 180 min in a vacuum furnace under pure argon (99.99%) and commercially pure nitrogen gas atmospheres. Samples were also maraged in an air furnace under commercially pure nitrogen atmosphere for comparison. In all these samples increase in the weight% of the samples and different surface colors i.e. bright, golden or brown were observed. The chemical elements as a function of depth after maraging were analyzed by Auger Electron Spectroscopy (AES) to investigate the reasons for the coloration of the surfaces of the samples. The AES revealed that oxygen, nitrogen and carbon elements are present at the top of the sample surface. It is concluded that the surface films formed were homogeneous due to the binding of N2 with the Ti, Fe and Co; binding of O2 with the Fe and binding of the C with the Mo. The nature of film appears to be chemisorbed reaction between the alloying elements and the O2, N2 and C, probably present as impurity in the gases used.read more

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Anwar ul Haq, M. Afzal Khan and Abdul Qadeer Khan

A New Family of Energetic Complexes Constructed From Alkali Metals (K, Rb and Cs) and 7-Amino-4,6-dinitrobenzofuroxan: Crystal Structures, Thermal Decomposition Behaviors, Sensitivity and Catalytic Properties

This work reported a new family energetic complexes constructed from alkali metals (K, Rb and Cs) and 7-amino-4,6-dinitrobenzofuroxan (ADNBF).The crystal structures, thermal decomposition behaviors, sensitivity and catalytic properties of the novel materials were characterized by using X-ray diffraction, TG-DSC measurements and mechanical sensitivity tests.read more

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Jian Cheng, Zuliang Liu, Zhenming Li, Yan Dong, Yu Zheng, Rui Wang and Li Sun

Removal of Anionic dye from Industrial Effluents with Raw and Chemically Modified Chickpea Husk

Alizarin Red S is an industrial dye commonly used for dyeing the fabric in textile industry. In present work the parameters to remove this dye from aqueous media by adsorption on raw as well as chemically modified chickpea husk have been investigated. Besides checking the effects of concerned parameters like time of contact, dose of adsorbent, pH, speed of agitation and temperature, for both raw and zinc modified chickpea husk were characterized for functional groups by FTIR spectroscopy. To investigate the adsorption mechanism, Langmuir, Freundlich and Temkin isotherms were plotted. Kinetic and thermodynamic studies were also performed to understand the nature of adsorption process. Chickpea husk proved itself as an effective and cheap bio-adsorbent, which is easily available in abundance at indigenous level. When treated with zinc chloride the removal efficiency of chickpea increased more than two folds.read more

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Amara Dar, Amna Safdar and Jamil Anwar

Tyrosinase and Carbonic Anhydrase Enzymes Inhibition Studies of Vanadium(V) Complexes

Present study endeavors synthesis of series of vanadium(V) hydrazide complexes and its enzyme inhibition studies. Octahedral structure of complexes has been evaluated previously using conductance measurements, spectroscopic techniques involving IR, 1H-NMR and 13C-NMR, elemental analysis using CHN technique. Complexes 1c-12c have found to exhibit monomeric form with hydrazides behaving as bidentate ligand coordinating by their N and O atoms, while two oxygen atoms have also been found to show attachment with the metal centre. This study includes activity of vanadium(V) complexes to inhibit tyrosinase and carbonic anhydrase enzymes. For inhibition of carbonic anhydrase all, while for tyrosinase most of the hydrazide ligands were found to be inactive. Vanadium(V) complexes with these hydrazides have found to bear variable degree of carbonic anhydrase and tyrosinase inhibition activity. Some of the vanadium(V) hydrazide complexes were found to be potent inhibitors of tyrosinase enzyme and carbonic anhydrase as well.read more

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Sadaf Sultan, Uzma Ashiq, Rifat Ara Jamal, Mohammad Mahroof-Tahir Rao Saeed Ahmad and Zara Shaikh