Journal of Nanotechnology The latest articles from Hindawi Publishing Corporation © 2016 , Hindawi Publishing Corporation . All rights reserved. Nanosensing Backed by the Uncertainty Principle Thu, 04 Feb 2016 13:12:00 +0000 Possibility for a novel type of sensors for detecting nanosized substances (e.g., macromolecules or molecule clusters) through their effects on electron tunneling in a double nanoscale semiconductor heterostructure is discussed. We studied spectral distributions of localized/delocalized states of a single electron in a double quantum well (DQW) with relation to slight asymmetry perturbations. The asymmetry was modeled by modification of the dot shape and the confinement potential. Electron energy uncertainty is restricted by the differences between energy levels within the spectra of separated QWs. Hence, we established a direct relationship between the uncertainty of electron localization and the energy uncertainty. We have shown in various instances that a small violation of symmetry drastically affects the electron localization. These phenomena can be utilized to devise new sensing functionalities. The charge transport in such sensors is highly sensitive to minuscule symmetry violation caused by the detected substance. The detection of the electron localization constitutes the sensor signal. I. Filikhin, A. Karoui, and B. Vlahovic Copyright © 2016 I. Filikhin et al. All rights reserved. Preparation of Three Types of Transformer Oil-Based Nanofluids and Comparative Study on the Effect of Nanoparticle Concentrations on Insulating Property of Transformer Oil Mon, 18 Jan 2016 14:20:43 +0000 Nanofluids have the potential to become the alternatives of conventional transformer oil for their exquisite electrical and thermal properties. Three kinds of nanoparticles with distinct conductivities, namely, nonconductive nanoparticle Al2O3, conductive nanoparticle Fe3O4, and semiconductive nanoparticle TiO2, with different concentrations from 5% to 40% w/v were selected and suspended into transformer oil to develop nanofluids. The lightening impulse breakdown strengths of the oil samples with and without nanoparticles were measured according to IEC standard methods. The positive impulse breakdown strength indicated that breakdown strength is first increased up to the maximum value at certain concentration and then starts decreasing. The results of negative impulse breakdown manifested that the breakdown voltages of nanofluids with different concentrations were less than the breakdown voltage of pure transformer oil. Different effect mechanisms of dielectric and conductive nanoparticles were also used to describe the difference among three prepared nanofluids. Qi Wang, Muhammad Rafiq, Yuzhen Lv, Chengrong Li, and Kai Yi Copyright © 2016 Qi Wang et al. All rights reserved. Advanced Materials and Nanotechnology for Sustainable Energy Development Wed, 30 Dec 2015 08:29:12 +0000 Ziyang Huo, Cheng Hao Wu, Zhongwei Zhu, and Yuxin Zhao Copyright © 2015 Ziyang Huo et al. All rights reserved. Optimization and Characterization of CMOS for Ultra Low Power Applications Tue, 22 Dec 2015 13:53:29 +0000 Aggressive voltage scaling into the subthreshold operating region holds great promise for applications with strict energy budget. However, it has been established that higher speed superthreshold device is not suitable for moderate performance subthreshold circuits. The design constraint for selecting and is much more flexible for subthreshold circuits at low voltage level than superthreshold circuits. In order to obtain better performance from a device under subthreshold conditions, it is necessary to investigate and optimize the process and geometry parameters of a Si MOSFET at nanometer technology node. This paper calibrates the fabrication process parameters and electrical characteristics for n- and p-MOSFETs with 35 nm physical gate length. Thereafter, the calibrated device for superthreshold application is optimized for better performance under subthreshold conditions using TCAD simulation. The device simulated in this work shows 9.89% improvement in subthreshold slope and 34% advantage in ratio for the same drive current. Mohd. Ajmal Kafeel, S. D. Pable, Mohd. Hasan, and M. Shah Alam Copyright © 2015 Mohd. Ajmal Kafeel et al. All rights reserved. Indoor Decontamination Textiles by Photocatalytic Oxidation: A Review Tue, 22 Dec 2015 13:45:50 +0000 A large number of researches have been made to make the textile intelligent and smarter; this is achieved by imparting functionality to the textile materials. The indoor environment possesses a variety of pollutants which do not come from the outer environment, but they come from the inner environment itself. Today, the smarter fabrics that may clean the indoor air have been studied by various researchers. The smarter fabrics contain the nanocoating of semiconductor oxides, mostly TiO2; thus the synthesis and application of these nanoparticles on the textile material have been reviewed in this paper. Moreover, there are lots of environmental and health issues regarding nanoparticles that have also been discussed in brief. Hafeezullah Memon, Sohail Yasin, Nazakat Ali Khoso, and Munir Hussain Copyright © 2015 Hafeezullah Memon et al. All rights reserved. Biological Synthesis of Silver Nanoparticles by Cell-Free Extract of Spirulina platensis Sun, 13 Dec 2015 06:20:05 +0000 The present study explores biological synthesis of silver nanoparticles (AgNPs) using the cell-free extract of Spirulina platensis. Biosynthesised AgNPs were characterised by UV-Vis spectroscopy, SEM, TEM, and FTIR analysis and finally evaluated for antibacterial activity. Extracellular synthesis using aqueous extract of S. platensis showed the formation of well scattered, highly stable, spherical AgNPs with an average size of 30–50 nm. The size and morphology of the nanoparticles were confirmed by SEM and TEM analysis. FTIR and UV-Vis spectra showed that biomolecules, proteins and peptides, are mainly responsible for the formation and stabilisation of AgNPs. Furthermore, the synthesised nanoparticles exhibited high antibacterial activity against pathogenic Gram-negative, that is, Escherichia coli, MTCC-9721; Proteus vulgaris, MTCC-7299; Klebsiella pneumoniae, MTCC-9751, and Gram-positive, that is, Staphylococcus aureus, MTCC-9542; S. epidermidis, MTCC-2639; Bacillus cereus, MTCC-9017, bacteria. The AgNPs had shown maximum zone of inhibition (ZOI) that is in P. vulgaris. Use of such a microalgal system provides a simple, cost-effective alternative template for the biosynthesis of nanomaterials of silver in a large scale that could be of great use in biomedical applications. Gaurav Sharma, Nakuleshwar Dut Jasuja, Manoj Kumar, and Mohammad Irfan Ali Copyright © 2015 Gaurav Sharma et al. All rights reserved. Nanosized Particles of Silica and Its Derivatives for Applications in Various Branches of Food and Nutrition Sectors Tue, 08 Dec 2015 08:24:27 +0000 Nanosized particles of silica and its derivatives have been identified as versatile for a broad range of science, technology, and engineering applications. In this paper, an effort has been made to provide a short review from the available literature information on their applications in various branches of food and nutrition sectors. The information provided in this paper describes various parameters affecting their performances and efficiencies. The properties and applications of nanosilica and its derivatives have been compared with microsilica and bulk-silica for their performances. The use of nanosized particles of silica and its derivatives provides a number of advantages. Their efficiencies and performances are significantly higher than those of the traditional ones. Mohammad Reza Kasaai Copyright © 2015 Mohammad Reza Kasaai. All rights reserved. Fabrication of Surface Level Cu/SiCp Nanocomposites by Friction Stir Processing Route Mon, 07 Dec 2015 11:33:04 +0000 Friction stir processing (FSP) technique has been successfully employed as low energy consumption route to prepare copper based surface level nanocomposites reinforced with nanosized silicon carbide particles (SiCp). The effect of FSP parameters such as tool rotational speed, processing speed, and tool tilt angle on microstructure and microhardness was investigated. Single pass FSP was performed based on Box-Behnken design at three factors in three levels. A cluster of blind holes 2 mm in diameter and 3 mm in depth was used as particulate deposition technique in order to reduce the agglomeration problem during composite fabrication. K-type thermocouples were used to measure temperature histories during FSP. The results suggest that the heat generation during FSP plays a significant role in deciding the microstructure and microhardness of the surface composites. Microstructural observations revealed a uniform dispersion of nanosized SiCp without any agglomeration problem and well bonded with copper matrix at different process parameter combinations. X-ray diffraction study shows that no intermetallic compound was produced after processing. The microhardness of nanocomposites was remarkably enhanced and about 95% more than that of copper matrix. Cartigueyen Srinivasan and Mahadevan Karunanithi Copyright © 2015 Cartigueyen Srinivasan and Mahadevan Karunanithi. All rights reserved. Controllable Synthesis of Zn2GeO4 Nanorods for Photocatalytic Reduction of Aqueous Cr(VI) and Oxidation of Organic Pollutants Thu, 26 Nov 2015 06:30:29 +0000 Zn2GeO4 nanorods were successfully synthesized by a simple hydrothermal method. The composition, morphology, and optical properties of as-synthesized Zn2GeO4 samples were characterized by X-ray diffraction, scan electron microscopy, and UV-vis diffuse reflectance spectra. The photocatalytic properties of Zn2GeO4 nanorods were evaluated by the reduction of Cr(VI) and oxidation of organic pollutants in aqueous solution. The effects of solution pH on Cr(VI) reduction by Zn2GeO4 nanorods were studied in detail. The results indicated that the efficiency of Cr(VI) reduction was highest at pH 5.96. Moreover, Zn2GeO4 nanorods also showed excellent photocatalytic ability for the oxidation of organic pollutants such as rhodamine B and 4-nitrophenol. Jin Liu, Xiaodan Jin, Yurong Shi, and Mingming Qiao Copyright © 2015 Jin Liu et al. All rights reserved. Low Threshold, Wide Dynamic Range, Tunable, All-Optical Self-Modulator Based on Fano Resonance and Out-of-Plane Coupling in a Slab Photonic Crystal with a Graphene Layer Wed, 25 Nov 2015 08:07:15 +0000 We demonstrate an all-optical modulator based on self-modulation in a one-dimensional slab photonic crystal (PhC) by using optical Kerr nonlinearity of graphene and Fano resonance effect. It has been shown that the effect of Fano resonance in a one-dimensional slab PhC for intensity enhancement can provide low threshold (~1 MW/cm2), high frequency (>1 THz), and wide dynamic range (>3 THz) tunability for the all-optical self-modulator. Such a self-modulator can find applications in optical pulse generations, optical clocks, frequency shifting, and so forth. Reza Asadi and Zhengbiao Ouyang Copyright © 2015 Reza Asadi and Zhengbiao Ouyang. All rights reserved. Synthesis, Characterization, and In Vitro Drug Delivery Capabilities of (Zn, Al)-Based Layered Double Hydroxide Nanoparticles Tue, 17 Nov 2015 08:10:22 +0000 There is an urgent need for the development of alternative strategies for effective drug delivery to improve the outcome of patients suffering from deadly diseases such as cancer. Nanoparticles, in particular layered double hydroxide (LDH) nanoparticles, have great potential as nanocarriers of chemotherapeutic molecules. In this study, we synthesized (Zn, Al)-LDH nanoparticles and report their enhanced pH-dependent stability in comparison to the commonly used (Mg, Al)-LDH nanoparticles. Fluorescein isothiocyanate (FITC) and valproate (VP) were intercalated into (Zn, Al)-LDH nanoparticles to study cellular uptake, biocompatibility, and drug delivery capabilities using cultured pancreatic adenocarcinoma BxPC3 cells. Fluorescence measurements indicated that FITC-intercalated LDH nanoparticles showed a greater degree of energy-dependent uptake rather than passive uptake by BxPC3 cells, especially at high concentrations of nanoparticles. Tetrazolium-based colorimetric assays indicated that BxPC3 cells treated with VP-intercalated LDH nanoparticles showed a significant reduction in cell viability along with about 30-fold reduction in IC50 compared to the drug alone. In contrast, the non-drug-intercalated LDH nanoparticles did not affect the cell viability indicating very low innate cytotoxicity. Our research indicates that the superior properties of (Zn, Al)-LDH nanoparticles make them ideal candidates for further development as in vivo chemotherapy drug delivery agents. Vinay J. Nagaraj, Xiaodi Sun, Jiten Mehta, Mac Martin, Thi Ngo, and Sandwip K. Dey Copyright © 2015 Vinay J. Nagaraj et al. All rights reserved. Research on Acetylene Sensing Properties and Mechanism of SnO2 Based Chemical Gas Sensor Decorated with Sm2O3 Mon, 09 Nov 2015 11:12:53 +0000 Acetylene C2H2 gas is one of the most important fault characteristic hydrocarbon gases dissolved in oil immersed power transformer oil. This paper reports the successful preparation and characterization of samarium oxide Sm2O3 decorated tin oxide SnO2 based sensors with hierarchical rod structure for C2H2 gas detection. Pure and Sm2O3 decorated SnO2 sensing structures were synthesized by a facile hydrothermal method and characterized by XRD, FESEM, TEM, EDS, and XPS measurements, respectively. Planar chemical gas sensors with the synthesis samples were fabricated, and their sensing performances to C2H2 gas were systematically performed and automatically recorded by a CGS-1 TP intelligent gas sensing analysis system. The optimum operating temperature of the Sm2O3 decorated SnO2 based sensor towards 50 μL/L of C2H2 is 260°C, and its corresponding response value is 38.12, which is 6 times larger than the pure one. Its response time is about 8–10 s and 10–13 s for recovery time. Meanwhile good stability and reproducibility of the decorated sensor to C2H2 gas are also obtained. Furthermore, the proposed sensor exhibits excellent C2H2 selectivity among some potential interface gases, like H2 and CO gas. All sensing results indicate the sensor fabricated with oxide Sm2O3 decorated SnO2 nanorods might be a promising candidate for C2H2 detection in practice. Qu Zhou, Meiqing Cao, Wude Li, Chao Tang, and Shiping Zhu Copyright © 2015 Qu Zhou et al. All rights reserved. Harmful Effects of Nanoparticles on Animals Tue, 03 Nov 2015 08:58:13 +0000 Since several years nanoparticles (NPs) are produced by industries and used in several fields of activities. They are finally found in aquatic and terrestrial environments, where they are ingested by living organisms in which they accumulate, before being eliminated. In organisms, NPs represent foreign elements with their own physicochemical properties due to their small size. So NPs may interfere with the normal physiological mechanisms of the embryos, growing animals, and adults, and it is indispensable to understand their potentially direct or indirect harmful effects on living organisms. It has been already shown that NPs could be toxic to bacteria, algae, invertebrates, and vertebrates. In this review, several examples of recent studies are given. We will examine successively the effects of NPs on terrestrial and semiaquatic and aquatic vertebrate and invertebrate animals. Jean-Marie Exbrayat, Elara N. Moudilou, and Emmanuel Lapied Copyright © 2015 Jean-Marie Exbrayat et al. All rights reserved. Influence of Buffer Agent Concentration on the Optical Properties from CdS Nanocrystals on Silicon Nanoporous Pillar Array Sun, 01 Nov 2015 13:58:27 +0000 The chemical bath deposition (CBD) method is very crucial to the reaction rate. Generally, the rate can be controlled through tuning buffer agent concentration. CdS nanocrystals on the silicon nanoporous pillar array (CdS/Si-NPA) have been prepared through the CBD method. By varying the buffer agent concentration, the reaction rates can be tuned. The diffraction peaks of hexagonal CdS and Cd can be observed due to the reduction of Cd2+ caused by the silicon nanoporous pillar array. The average size of CdS nanocrystals is decreased with the increasing buffer agent concentration and the optical band gaps from CdS nanocrystals are increased. From the photoluminescence of CdS/Si-NPA, it can be observed that the blue emissions are independent of the buffer agent concentration and the green emissions show blue shift with the increasing buffer agent concentration. Peng Fei Ji, Wei Fen Jiang, Yong Li, Yue Li Song, Ming Li Wan, and Feng Qun Zhou Copyright © 2015 Peng Fei Ji et al. All rights reserved. Biosynthesis of Silver Nanoparticles and Its Applications Wed, 28 Oct 2015 12:36:38 +0000 Silver nanoparticles possess unique properties which find myriad applications such as antimicrobial, anticancer, larvicidal, catalytic, and wound healing activities. Biogenic syntheses of silver nanoparticles using plants and their pharmacological and other potential applications are gaining momentum owing to its assured rewards. This critical review is aimed at providing an insight into the phytomediated synthesis of silver nanoparticles, its significant applications in various fields, and characterization techniques involved. M. Jannathul Firdhouse and P. Lalitha Copyright © 2015 M. Jannathul Firdhouse and P. Lalitha. All rights reserved. Protrusion of the Rod Electrode in the Electrospinning Process Tue, 27 Oct 2015 08:49:14 +0000 The paper focuses on the influence of the protrusion of the rod electrode on critical voltage in the DC electrospinning process. On the testing and industrial DC electrospinning devices, electrodes of any kind are extended towards the counter electrode. This provides the maximal, that is, supercritical, electric field intensity on the spinning-electrode orifice that is found to be higher than on the other supplementary parts. The principal study and experiments with basic apparatus were carried out and presented by Taylor in 1966. This study is focused on the arrangement closely related to the design of the real electrospinning device with respect to the safety and technological aspects. Results of the carried out experiments of the rod spinning-electrode are compared with the electrostatic simulation and analytical calculation. The presented effect of the electrode protrusion on the potential difference and the critical field strength introduces valuable information for the designers of electrospinning machines as well as for the setting up of the optimal technological parameters for producing modern nonwoven textile products. Jan Valtera, Lucie Vysloužilová, Jiří Komárek, Josef Skřivánek, Petr Žabka, Jaroslav Beran, and David Lukáš Copyright © 2015 Jan Valtera et al. All rights reserved. Optical and Sensing Properties of Cu Doped ZnO Nanocrystalline Thin Films Tue, 27 Oct 2015 08:30:43 +0000 Undoped and Cu doped ZnO films of two different molarities deposited by spray pyrolysis using zinc nitrate and cupric chloride as precursors show polycrystalline nature and hexagonal wurtzite structure of ZnO. The crystallite size varies between 10 and 21 nm. Doping increases the transmittance of the films whereas the optical band gap of ZnO is reduced from 3.28 to 3.18 eV. With increment in doping the surface morphology changes from irregular shaped grains to netted structure with holes and then to net making needle-like structures which lends gas sensing characteristics to the films. Undoped ZnO shows maximum sensitivity at 400°C for higher concentration of CO2. The sensitivity of Cu doped sample is maximum at 200°C for all CO2 concentrations from 500 to 4000 ppm. R. K. Shukla, Anchal Srivastava, Nishant Kumar, Akhilesh Pandey, and Mamta Pandey Copyright © 2015 R. K. Shukla et al. All rights reserved. Properties of Silicon Dioxide Amorphous Nanopowder Produced by Pulsed Electron Beam Evaporation Thu, 22 Oct 2015 12:19:55 +0000 SiO2 amorphous nanopowder (NP) is produced with the specific surface area of 154 m2/g by means of evaporation by a pulsed electron beam aimed at Aerosil 90 pyrogenic amorphous NP (90 m2/g) as a target. SiO2 NP nanoparticles showed improved magnetic, thermal, and optical properties in comparison to Aerosil 90 NP. Possible reasons of emergence of d0 ferromagnetism at the room temperature in SiO2 amorphous NP are discussed. Photoluminescent and cathode luminescent properties of the SiO2 NP were investigated. Vladislav G. Il’ves, Michael G. Zuev, and Sergey Yu. Sokovnin Copyright © 2015 Vladislav G. Il’ves et al. All rights reserved. Functionalized Multiwalled Carbon Nanotubes-Reinforced Vinylester/Epoxy Blend Based Nanocomposites: Enhanced Mechanical, Thermal, and Electrical Properties Thu, 08 Oct 2015 13:51:04 +0000 This paper presents a study on the mechanical, thermal, and electrical characterization of a new class of low cost multiphase nanocomposites consisting of Vinylester resin/epoxy (VER/EP) blend (40 : 60 w/w) reinforced with amine functionalized multiwalled carbon nanotubes (f-MWCNTs). Five different sets of VER/EP nanocomposites are fabricated with addition of 0, 1, 3, 5, and 7 wt.% of f-MWCNTs. A detailed investigation of mechanical properties like tensile strength, impact strength, Young’s modulus, and hardness, thermal properties like thermogravimetric analysis (TGA) and thermal conductivity, electrical properties like dielectric strength, dielectric constant, and electrical conductivity, and corrosive and swelling properties of the nanocomposites has been carried out. Here, we report significant improvement in all the above properties of the fabricated nanocomposites with nanofiller (f-MWCNTs) addition compared to the virgin blend (0 wt. nanofiller loading). The properties are best observed in case of 5 wt.% nanofiller loading with gradual deterioration thereafter which may be due to the nucleating tendency of the nanofiller particles. Thus the above nanocomposites could be a preferable candidate for a wide range of structural, thermal, electrical, and solvent based applications. Ankita Pritam Praharaj, Dibakar Behera, Tapan Kumar Bastia, and Arun Kumar Rout Copyright © 2015 Ankita Pritam Praharaj et al. All rights reserved. Metal Oxide Nanostructures: Synthesis, Properties, and Applications Mon, 05 Oct 2015 13:06:39 +0000 Lin-Hua Xu, Dnyaneshwar S. Patil, Jiazhi Yang, and Jingzhong Xiao Copyright © 2015 Lin-Hua Xu et al. All rights reserved. Preparation of ZnO/CdS/BC Photocatalyst Hybrid Fiber and Research of Its Photocatalytic Properties Thu, 01 Oct 2015 12:14:00 +0000 An environment-friendly biomaterial bacterial cellulose (BC) is introduced to substitute general organic polymers to assist the preparation of ZnO/CdS/BC photocatalyst hybrid nanofiber through coprecipitation method under the low-temperature condition. The XRD, XPS, and SEM results show that high load of ZnO/CdS/BC ternary hybrid fiber can be produced. TGA curves scan shows that ZnO/CdS/BC hybrid fiber has better thermal properties than bacterial cellulose. The UV-Vis spectra of the ZnO/CdS/BC hybrid nanofiber (0, 10, 20, and 50 wt%, resp.) show that photocatalytic activities of ZnO/CdS/BC are influenced by the added amount of CdS. The degradation curve of methyl shows that ZnO/CdS/BC nanohybrid fibers exhibit excellent photocatalytic efficiency. Beibei Dai, Cheng Chao, Xiaoyu Lu, Qingcheng Xia, Jing Han, Fei Mao, Jiazhi Yang, and Dongping Sun Copyright © 2015 Beibei Dai et al. All rights reserved. Comparing and Optimizing Nitrate Adsorption from Aqueous Solution Using Fe/Pt Bimetallic Nanoparticles and Anion Exchange Resins Thu, 01 Oct 2015 12:13:05 +0000 This research work was carried out for the removal of nitrate from raw water for a drinking water supply. Nitrate is a widespread ground water contaminant. Methodology employed in this study included adsorption on metal based nanoparticles and ion exchange using anionic resins. Fe/Pt bimetallic nanoparticles were prepared in the laboratory, by the reduction of their respective salts using sodium borohydride. Scanning electron microscope, X-ray diffraction, energy dispersive spectrometry, and X-ray florescence techniques were utilized for characterization of bimetallic Fe/Pt nanoparticles. Optimum dose, pH, temperature, and contact time were determined for removal through batch tests, both for metal based nanoparticles and anionic exchange resin. Adsorption data fitted well the Langmuir isotherm and conformed to the pseudofirst-order kinetic model. Results indicated 97% reduction in nitrate by 0.25 mg/L of Fe/Pt nanoparticles at pH 7 and 83% reduction in nitrate was observed using 0.50 mg/L anionic exchange resins at pH 4 and contact time of one hour. Overall, Fe/Pt bimetallic nanoparticles demonstrated greater removal efficiency due to the small particle size, extremely large surface area (627 m2/g), and high adsorption capacity. Muhammad Daud, Zahiruddin Khan, Aisha Ashgar, M. Ihsan Danish, and Ishtiaq A. Qazi Copyright © 2015 Muhammad Daud et al. All rights reserved. Analysis of Thermal Properties on Backward Feed Multieffect Distillation Dealing with High-Salinity Wastewater Thu, 01 Oct 2015 12:12:16 +0000 Theoretical investigations on thermal properties of multieffect distillation (MED) are presented to approach lower capital costs and more distillated products. A mathematical model, based on the energy and mass balance, is developed to (i) evaluate the influences of variations in key parameters (effect numbers, evaporation temperature in last effect, and feed salinity) on steam consumption, gained output ratio (GOR), and total heat transfer areas of MED and (ii) compare two operation modes (backward feed (BF) and forward feed (FF) systems). The result in the first part indicated that GOR and total heat transfer areas increased with the effect numbers. Also, higher effect numbers result in the fact that the evaporation temperature in last effect has slight influence on GOR, while it influences the total heat transfer areas remarkably. In addition, an increase of feed salinity promotes the total heat transfer areas but reduces GOR. The analyses in the second part indicate that GOR and total heat transfer areas of BF system are higher than those in FF system. One thing to be aware of is that the changes of steam consumption can be omitted, considering that it shows an opposite trend to GOR. Jianliang Xue, Qinqin Cui, Jie Ming, Yu Bai, and Lin Li Copyright © 2015 Jianliang Xue et al. All rights reserved. Iron Contamination Mechanism and Reaction Performance Research on FCC Catalyst Thu, 01 Oct 2015 12:11:28 +0000 FCC (Fluid Catalytic Cracking) catalyst iron poisoning would not only influence units’ product slate; when the poisoning is serious, it could also jeopardize FCC catalysts’ fluidization in reaction-regeneration system and further cause bad influences on units’ stable operation. Under catalytic cracking reaction conditions, large amount of iron nanonodules is formed on the seriously iron contaminated catalyst due to exothermic reaction. These nodules intensify the attrition between catalyst particles and generate plenty of fines which severely influence units’ smooth running. A dense layer could be formed on the catalysts’ surface after iron contamination and the dense layer stops reactants to diffuse to inner structures of catalyst. This causes extremely negative effects on catalyst’s heavy oil conversion ability and could greatly cut down gasoline yield while increasing yields of dry gas, coke, and slurry largely. Research shows that catalyst’s reaction performance would be severely deteriorated when iron content in E-cat (equilibrium catalyst) exceeds 8000 μg/g. Zhaoyong Liu, Zhongdong Zhang, Pusheng Liu, Jianing Zhai, and Chaohe Yang Copyright © 2015 Zhaoyong Liu et al. All rights reserved. Growth Mechanisms of Nanostructured Titania in Turbulent Reacting Flows Thu, 01 Oct 2015 11:52:35 +0000 Titanium dioxide (titania) is used in chemical sensors, pigments, and paints and holds promise as an antimicrobial agent. This is due to its photoinduced activity and, in nanostructured form, its high specific surface area. Particle size and surface area result from the interplay of fluid, chemical, and thermal dynamics as well as nucleation, condensation and coagulation. After nucleation, condensation, and coagulation are the dominant phenomena affecting the particle size distribution. Manufacture of nanostructured titania via gas-phase synthesis often occurs under turbulent flow conditions. This study examines the competition between coagulation and condensation in the growth of nanostructured titania. Direct numerical simulation is utilized in simulating the hydrolysis of titanium tetrachloride to produce titania in a turbulent, planar jet. The fluid, chemical, and particle fields are resolved as a function of space and time. As a result, knowledge of titania is available as a function of space, time, and phase (vapor or particle), facilitating the analysis of the particle dynamics by mechanism. Results show that in the proximal region of the jet nucleation and condensation are the dominant mechanisms. However once the jet potential core collapses and turbulent mixing begins, coagulation is the dominant mechanism. The data also shows that the coagulation growth-rate is as much as twice the condensation growth-rate. Sean C. Garrick Copyright © 2015 Sean C. Garrick. All rights reserved. Experimental Assessment of Water Sprays Utilization for Controlling Hydrogen Sulfide Releases in Confined Space Thu, 01 Oct 2015 08:41:22 +0000 This paper reported the utilization of water spray for controlling H2S release in a confined space, which is especially important in industry. A typical spray tower was modified to simulate the confined space for people's enterable routine operation (e.g., pump room), in which the dilution capacity of water sprays can also be evaluated. This work consists of two parts: the first part focuses on the influences of different operating conditions on chemical dilution capacities of water sprays in mechanisms; the second one is comparison between two nozzle configurations for evaluating their feasibilities of practical application. Water sprays express eligible performance for H2S release control even though their dilution capacity was weakened at high gaseous concentrations and rates of releases. The presence of Na2CO3 can significantly improve absorption effectiveness of H2S in water and the optimal Na2CO3 additive was found to be 1.0 g·L−1 in this test. Compared with Na2CO3, adjusting water flow rate may be an effective strategy in enhancing dilution capacity of water sprays due to the fact that larger flow rate led to both less dilution time (TD) and dilution concentration (CD). Furthermore, multinozzle configuration is more efficient than single-nozzle configuration under the same water consumption. Dongfeng Zhao, Chao Li, Jun Liu, Guoying Zhou, Qingdong Zhang, and Chunshuang Liu Copyright © 2015 Dongfeng Zhao et al. All rights reserved. Synthesis and Application of Magnetic Photocatalyst of Ni-Zn Ferrite/TiO2 from IC Lead Frame Scraps Thu, 01 Oct 2015 08:38:46 +0000 IC lead frame scraps with about 18.01% tin, 34.33% nickel, and 47.66% iron in composition are industrial wastes of IC lead frame production. The amount of thousand tons of frame scraps in Taiwan each year is treated as scrap irons. Ni-Zn ferrites used in high frequent inductors and filters are produced from Ni-Zn ferrite powders by pressing and sintering. The amount of several ten thousand tons of ferrites of in compositions is consumed annually in the whole world. Therefore, these IC lead frame scraps will be used in this research as raw materials to fabricate magnetic ferrite powders and combined subsequently with titanium sulfate and urea to produce magnetic photocatalysts by coprecipitation for effective waste utilization. The prepared Ni-Zn ferrite powder and magnetic photocatalyst (Ni-Zn ferrite/TiO2) were characterized by ICP, XRF, XRD, EDX, SEM, SQUID, and BET. The photocatalytic activity of synthesized magnetic photocatalysts was tested by FBL dye wastewater degradation. TOC and ADMI measurement for degradation studies were carried out, respectively. Langmuir-Hinshelwood kinetic model of the prepared magnetic TiO2 proved available for the treatments. Wastes are transformed to valuable magnetic photocatalysts in this research to solve the separation problem of wastewater and TiO2 photocatalysts by magnetic field. Robert Liu and H. T. Ou Copyright © 2015 Robert Liu and H. T. Ou. All rights reserved. Influence of OH− Ion Concentration on the Surface Morphology of ZnO-SiO2 Nanostructure Thu, 01 Oct 2015 08:37:37 +0000 The influence of varying OH− ion concentration on the surface morphology of chemically deposited ZnO-SiO2 nanostructures on glass substrate was investigated. The morphological features, phase structure, and infrared characteristics were examined by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR), respectively. Results revealed that silica significantly changes the hexagonal morphology of bare ZnO rod to “pointed tips” when using low initial OH− precursor concentration. Increasing OH− ion concentration resulted in a “flower-like” formation of ZnO-SiO2 and a remarkable change from “pointed tips” to “hemispherical tips” at the top surface of the rods. The surface capping of SiO2 to ZnO leads to the formation of these “hemispherical tips.” The infrared spectroscopic analysis showed the characteristics peaks of ZnO and SiO2 as well as the Si-O-Zn band which confirms the formation of ZnO-SiO2. Phase analysis manifested that the formed ZnO-SiO2 is of wurtzite structure. Furthermore, a possible growth mechanism is proposed based on the obtained results. Jessica Ven G. Tinio, Key T. Simfroso, Amber Dea Marie V. Peguit, and Rolando T. Candidato Jr. Copyright © 2015 Jessica Ven G. Tinio et al. All rights reserved. Silica Sol-Gel Entrapment of the Enzyme Chloroperoxidase Thu, 01 Oct 2015 08:33:22 +0000 The enzyme chloroperoxidase (CPO) was immobilized in silica sol-gel beads prepared from tetramethoxysilane. The average pore diameter of the silica host structure (~3 nm) was smaller than the globular CPO diameter (~6 nm) and the enzyme remained entrapped after sol-gel maturation. The catalytic performance of the entrapped enzyme was assessed via the pyrogallol peroxidation reaction. Sol-gel beads loaded with 4 μg CPO per mL sol solution reached 9–12% relative activity compared to free CPO in solution. Enzyme kinetic analysis revealed a decrease in but no changes in or . Product release or enzyme damage might thus limit catalytic performance. Yet circular dichroism and visible absorption spectra of transparent CPO sol-gel sheets did not indicate enzyme damage. Activity decline due to methanol exposure was shown to be reversible in solution. To improve catalytic performance the sol-gel protocol was modified. The incorporation of 5, 20, or 40% methyltrimethoxysilane resulted in more brittle sol-gel beads but the catalytic performance increased to 14% relative to free CPO in solution. The use of more acidic casting buffers (pH 4.5 or 5.5 instead of 6.5) resulted in a more porous silica host reaching up to 18% relative activity. Tuan Le, Selina Chan, Bassem Ebaid, and Monika Sommerhalter Copyright © 2015 Tuan Le et al. All rights reserved. TiO2 Nanocatalysts Supported on a Hybrid Carbon-Covered Alumina Support: Comparison between Visible Light and UV Light Degradation of Rhodamine B Thu, 01 Oct 2015 07:03:22 +0000 Titania nanoparticles were successfully supported on carbon-covered alumina (CCA) supports via the impregnation method to form carbon-covered alumna titania (CCA/TiO2). The CCA supports were synthesised through an equilibrium adsorption of toluene 2,4-diisocyante where the N=C=O irreversibly adsorbs on the alumina and pyrolysis at 700°C affords CCA supports. These CCA/TiO2 nanocatalysts were tested for their photocatalytic activity both under UV and visible light using Rhodamine B as a model pollutant. The reaction rate constant of the CCA/TiO2 was found to be higher than that of unsupported titania and the reaction kinetics were found to follow an apparent first-order rate law. The CCA/TiO2 nanocatalysts had a much larger surface area than the unsupported titania and they exhibited overall higher photodegradation efficiency under both UV and visible light than unsupported TiO2. Mphilisi M. Mahlambi, Ajay K. Mishra, Shivani B. Mishra, Rui W. Krause, Bhekie B. Mamba, and Ashok M. Raichur Copyright © 2015 Mphilisi M. Mahlambi et al. All rights reserved.