VOLUME 42, NO5, OCT-2020

Study of Dielectric and Piezoelectric Properties of (1-x)PZT-xSFN Ceramics Prepared by Conventional Solid State Reaction Method

Modified-PZT ceramics with a formula (1-x)Pb(Zr0.53 Ti0.47)O3-xSr(Fe2/3, Nb1/3)O3 (doped with isovalent: Sr2+, acceptor: Fe3+ and Donor: Nb5+ ions) abbreviated as (1-x)PZT-xSFN binary system with varying x (x= 0.02, 0.04, 0.06, 0.08 and 0.10) located near the morphotropic phase boundary (MPB) were prepared by a traditional process in a solid state. All the samples were sintered at a temperature of 1200°C during 2 h. The phase structure, the dielectric and piezoelectric properties of the system were studied. In-phase analysis used X-ray diffraction (XRD) at room temperature indicated that the structure of phase of sintered PZT-SFN ceramics was formed in single-phase with a crystalline structure tetragonal. Raman spectroscopy confirms the presence of this tetragonal phase. The optimum electrical parameters are obtained at 0.94Pb(Zr0.53Ti0.47)O3-0.06Sr(Fe2/3, Nb1/3)O3 system: kp= 66.10 %, d31= 145 pC/N, Qm= 473, tanδ= 1.11 %, and ɛr= 1009.read more

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Fares Kahoul, Louanes Hamzioui, Abderrezak Guemache, Michel Aillerie and Ahmed Boutarfaia

Investigation of the Effect of Substituent Species/Positions and Numbers on Removal of Toxicity from Chloro and Nitro Phenol Compounds with Fenton and Fenton-like Processes

Phenol derivatives containing substutient are used intensely in industry and their presence in surface and waste water is a problem requiring urgent solution due to their tendency for bioaccumulation, cancerogenic effects, high toxicity and weak biodegradability. In this study, the degradability and toxicity of chlorinated phenols 2-CP, 2,4-DCP and 4-CP and nitrated phenols 2-NP, 2,4-DNP and 4-NP were investigated. These phenols are included on the priority toxic pollutant list within the scope of clean water regulations according to both the US EPA-2014 and the European Union (2455/2001/CE) and form serious threats to public health and aqueous ecosystems. The degradability of chloro and nitro phenols was researched by applying the Fenton/Fenton-like processes (under optimal conditions) and measuring the model pollutant concentrations, COD and TOC parameters. The effects of substituent type/position and number were determined with toxicity measurements using Vibrio fischeri bacteria (DIN/EN/ISO 11348-2). Statistical analysis was performed in detail for both Fenton/Fenton-like processes (T test) and toxicology measurement results (One-Way ANOVA) for the model pollutants (P<0.05). In the first stage of the study, model pollutant removal of 95-100%, COD removal of 64-85% / 60-77% and TOC removal efficiency of 52-65% and 40-61% were achieved respectively with Fenton and Fenton-like processes. In the second stage of the study, the results of toxicity measurements of the pollutants performed before processing found EC50(mg/L) and toxic unit values (TU) were 8.10-12.34 for 2-CP, 2.24-44.67 for 2,4-DCP, 1.20-83.33 for 4-CP, 13.43-7.44 for 2-NP, 8.92-11.21 for 2,4-DNP, and 4.77-20.9 for 4-NP, respectively. After processing, the EC50/EC20 and TU values were determined to fall to unobservable levels. According to the order obtained with toxicity measurements of 4-CP > 2,4-DCP > 4-NP > 2-CP > 2,4-DNP > 2-NP, the chlor substituent had higher toxic effect compared to nitro. As the substituent numbers increase the toxicity increased; however, para position was identified to be more toxic compared to other positions. The reason for the 4 (para) position being more toxic than the 2,4 (ortho-para) position is thought to be due to the chlor or nitro linked to the 2 or ortho position binding to the OH group of phenol with a 5- and 6-member H-bridge in cis position forming a ring, which leads to inactivity.read more

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Zeynep Ceylan and Şeyda Deniz Aydın

Applications, Challenges and Development of Nanomaterials and Nanotechnology

Nanomaterials and nanotechnology have been rapidly developed and widely applied in antimicrobial, biosensors, nanomedicine, nano-electronic technology, reinforcement, water treatment, and so on. However, there are also many problems and challenges during using and developing nanomaterials and nanotechnology. Are they secure enough for the health of human beings? Do they cause the environmental pollution? And how can we sustainably develop nanomaterial and nanotechnology? In this review, we introduced the applications, potential threats and hazards, and development and prospect of nanomaterial and nanotechnology.read more

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Ling Zhang

Synthesis and Applications of Antimicrobial and UV Protected Polymeric glass coatings

polymeric materials along with nanoparticles are widely used to protect from microbial propagation. In humid environments, enclosed edifice is amongst the foremost propagation substrates aimed at microorganisms. Antimicrobial coatings could help to stop microbial proliferation or, reduce the number of microorganisms growing on inside buildings. This paper deals with inhibition of Escherichia coli bacteria by TiO2 and silver nano-particles doping along with poly acrylate-based copolymers. Coated glass was characterized for FTIR, antimicrobial activity, UV Visible Spectroscopy and water contact angle for hydrophobicity and SEM analysis for surface morphology. The disk diffusion method was used for bacterial inhibition. Results revealed that developed material has good adhesion with glass and shows transparency, hydrophobicity and antibacterial activity. Which shows that coating material can be used for significant antibacterial coatings to protect window glass table ware glass doors etc. further these coatings are transparent, UV radiation protected and hydrophobic in nature which also enhance the self-cleaning effects. In addition, the coating has photocatalytic activity due to the presence of TiO2 and showed momentous antibacterial events after 2,4 and 6 hrs and this efficiency would be increased by improving formulation composition.read more

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Phool Shahzadi and Syeda Rubina Gilani

Application of UV-Visible Spectrophotometric Method for the Estimation of Ciprofloxacin HCl and Levofloxacin Hemihydrate (Antibiotics) in Marketed Drugs

Ciprofloxacin HCl, 1-Cyclopropyl-6-fluoro-4-oxo-7-(piperazin1-yl)-1,4-dihydroquinoline-3-carboxylic acid, is a synthetic broad antibacterial compound belonging to the group of fluoroquinolones which is antimicrobial drug act through the inhibition of DNA-gyrase, an enzyme that is critical to bacterial chromosome replication. It is used in a wide range of infections of the urinary, respiratory and gastrointestinal tracts, as well as in skin structure and ocular infections. Levofloxacin Hemihydrate is a fluoroquinolone, has a broad-spectrum antibiotic activity against gram-positive and gram-negative bacteria and used in respiratory and urinary tract infections. Various Pakistani branded antibiotic drug samples containing Ciprofloxacin HCl and Levofloxacin Hemihydrate were collected from local market and their working standards from the material suppliers of Karachi city. Samples were analyzed by using UV-Vis spectrophotometer. Then the method was validated by linearity, accuracy, precision (reproducibility, intermediate precision) and range which suggested that method is appropriate and proper to determine the potency of these various brands of Ciprofloxacin HCl and Levofloxacin Hemihydrate. The analytical data suggest that the drug samples analyzed were within the limit of the Pharmacopeia requirement and criteria.read more

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Mir Munsif Ali Talpur, Tajnees Pirzada and Muhammad Afzal Arain

Photocatalytic Performance Evaluation of Bismuth Doped Tin-Dioxide under UV and Direct Sunlight Irradiation for Congo Red Dye Degradation

In the current research work, bismuth doped tin-dioxide (Bi-SnO2) was prepared by wet chemical co-precipitation method. The synthesized material was used as a photocatalyst in the degradation of congo red dye (CR) in its aqueous solution. The prepared catalyst was used in the uncalcined- and calcined forms for the photocatalytic reaction. The synthesized catalyst in both forms was characterized by UV-visible spectroscopy, scanning electron microscopy (SEM) and X-ray diffraction (XRD). The XRD revealed that the calcination of the Bi-SnO2 improved its crystallinity. The SEM showed that the Bi-SnO2 had average size less than 150nm. Photocatalytic degradation of CR dye was carried out under ultra-violet light as well as under sunlight. While testing the photocatalytic degradation performance, it was found that more than 80% of the CR was degraded by using Bi-SnO2 nanoparticles under both lighting conditions. Moreover, the calcined Bi-SnO2 nanoparticles showed better photocatalytic performance as compared to its uncalcined form. The present work provides a viable way to make efficient photocatalyst based-on Bi-SnO2 to employ under UV and sunlight for the degradation of the CR dye without the need of oxidizing or reducing agents.read more

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Nauman Ali, Adnan khan, Aaisha Riaz, Abdullah M. Asiri and Tahseen Kamal

Paper-Based Analytical Device for Rapid Naked-Eye Detection of Sulfide in Water Samples

This paper describes the development of a low-cost paper-based colorimetric analytical device for the accurate and rapid determination of sulfide. Under optimized conditions, Na2S was dropped in the uptake zone I and the probe in the uptake zone II, they converged to the detection zone via capillary force and formed an intense pink resorufin. Sulfide can be quantified based on the average color intensity values of the product “free resorufin”. The color intensity is recorded using a camera phone, and quantification was made using Adobe Photoshop. The as-developed analytical device detected sulfide in the range of 5–400 μM (R2 = 0.982) with the limit of detection (LOD) 1 μM, and was successfully applied in sulfide assay in spiked water samples including tap water and simulated waste water. Colorimetric results from the proposed paper-based colorimetric analytical device were consistent with that from methylene blue (MB) method.read more

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Lingzhi Zhao

Modified Zinc Oxide Nanoparticles for Corrosion Resistance Applications

Atmospheric corrosion is a big threat to the steel structures. This is because it compromises its structural integrity, aesthetic aspects and overall efficiency. An attempt has been made to counteract this through surface engineering of substrates including glass and steel by using modified zinc oxide nanoparticles to increase hydrophobicity. The synthesis of zinc oxide nanoparticles is carried out by using sol-gel method, thereafter these particles were modified by using stearic acid; a fatty acid. The zinc oxide nanoparticles were characterized by using X-ray diffraction analysis (XRD) which confirms the presence of hexagonal wurtzite structure. Moreover, the Scanning Electron microscopy (SEM) reveals the hexagonal wurtzite morphology of as prepared nanoparticles. Fourier transform infrared spectroscopy (FTIR) confirms the grafting of stearic acid on the surface of ZnO in bidentate form. The water Contact Angle obtained by using sessile drop method gives a statistical value of 140o which is of great interest due to higher water repellency and lower surface contact area. Finally, corrosion test was carried out on the coated steel substrate by means of conventional corrosion testing technique and it is observed that the coated sample decays three times slower than that of its bare steel counterpart.read more

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Ali Dad Chandio, Muhammad Hamza Saleem, Hasan Raza Khan, Iqra Naeem Hyder and Maryam Ali

Impact of Anionic Dopant Precursor on Nanostructured ZnO thin Films Surface Morphologies

The aim of this study is to investigate the impact of an anionic precursor [N2 gas and triethyleneamine (TEA) as nitrogen dopant source] to prepare anionic doped ZnO thin films surface morphologies, via a novel route - hydrothermal solution deposition at low temperature. The effect of dopant concentration under both with and without pH control was studied. The less populated doped ZnO crystal nearly had the same band gap as compared to undoped ZnO thin films. The photocatalytic activity of selected doped ZnO thin films were studied for the degrdation of 10 mg L-1 Methylene Blue under UV irradiation of 254nm. Based on the 1st order reaction rate constant results the morphology N2:S2-MS has shown highest degradation followed by N:S1-MS. Overall, the photocatalytic activity order is N2:S2-MS > N:S1-MS > N:S2-CG > N:S1-CG. In general, a significant variation in surface morphologies, crystal size and population, porosity and orientation were observed. This tailored-made variation enabled the doped ZnO thin films to successfully degrade the waste methylene blue effluents.read more

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Arshid Mahmood Ali, Aishah Mahpudz, Usman Saeed, Sami U. Rather, Ayyaz M. Nawaz Javaid A and Hui Zhang

Removal of Acid Textile Dye from the Aqueous Solution by a New Adsorbent Obtained from Waste Cotton from the Garment Plant

The paper investigates the possibility of removing acid dye from the aqueous solution by an adsorption process on new adsorbent prepared from waste cotton textile from the ready-made garment industry. It is a waste generated during the cutting of the layers of cotton knitwear, which is practically the product from the textile cutting process. The obtained adsorbent is a bulk material with heterogeneous porous particles, of ragged shapes. In particle interiors, there are pronounced cracks, cavities and channels that form the basis of microporous material. The qualitative and quantitative characterization of the obtained adsorbent shows that this is a relatively porous material where the carbon is dominant in the chemical composition. The results of textural properties of new adsorbent from cotton knitwear waste show different parameters which with their numerous values characterize the specific surface area, pore volume or pore diameter. It can be said that the obtained new adsorbent has micropores and small mesopores, which produce a high specific surface area. During adsorption, the longer contact time causes a greater amount of dye on the adsorbent, i.e. with the duration of the adsorption process the dye concentration in the solution decreases. A number of isotherms of two- (Langmuir, Freundlich and Jovanovic), three- (Toth, Sips and Radke-Prausnitz), and four-parameter models (Fritz-Schlunder and Marczewski-Jaroniec) were used to describe the adsorption process. The four-parameter isotherms are best covered by experimental points and most accurately describe the events of adsorption of acid dye on the surface and in the interior of the new adsorbent particles obtained from ready–made garment cotton waste. The results of this research suggest the possibility of practical application in the decolorization of the colored waste waters of the textile industry providing a contribution to protecting the environment from both an economic and a practical point of view.read more

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Aleksandra Micic, Dragan Djordjevic, Ivona Jankovic Castvan, Nenad Cirkovic, Bratislav Todorovic