Search results for: reusable catalyst

Authors: Fereshteh Chekin, Sepideh Sadeghi

Abstract:

Nickel nanoparticles have attracted much attention because of applications in catalysis, medical diagnostics and magnetic applications. In this work, we reported a simple and low-cost procedure to synthesize nickel oxide nanoparticles (NiO-NPs) by using sodium dodecyl sulphate (SDS) and gelatin as stabilizer. The synthesized NiO-NPs were characterized by a variety of means such as transmission electron microscope (TEM), powder X-ray diffraction (XRD), scanning electron microscope (SEM) and UV-vis spectroscopy. The results show that the NiO nanoparticles with high crystalline can be obtained using this simple method. The grain size measured by TEM was 16 in presence of SDS, which agrees well with the XRD data. SDS plays an important role in the formation of the NiO nanoparticles. Moreover, the NiO nanoparticles have been used as a solid phase catalyst for the decomposition of hydrazine hydrate at room temperatures. The decomposition process has been monitored by UV–vis analysis. The present study showed that nanoparticles are not poisoned after their repeated use in decomposition of hydrazine.

Keywords: nickel oxide nanoparticles, sodium dodecyl sulphate, synthesis, stabilizer

Procedia PDF Downloads 463

Authors: Sam Rasoulzadeh, Atefeh Mousavi

Abstract:

Fluidized bed reactors are known as highly exothermic and endothermic according to uniformity in temperature as a safe and effective mean for catalytic reactors. In these reactors, a wide range of catalyst particles can be used and by using a continuous operation proceed to produce in succession. Providing optimal conditions for the operation of these types of reactors will prevent the exorbitant costs necessary to carry out laboratory work. In this regard, a hydrodynamic analysis was carried out with heat transfer in the solid-gas fluidized bed reactor for solar thermal applications. The results showed that in the fluid flow the input of the reactor has a lower temperature than the outlet, and when the fluid is passing from the reactor, the heat transfer happens between cylinder and solar panel and fluid. It increases the fluid temperature in the outlet pump and also the kinetic energy of the fluid has been raised in the outlet areas.

Keywords: heat transfer, solar reactor, fluidized bed reactor, CFD, computational fluid dynamics

Procedia PDF Downloads 151

Authors: Yijin Kang

Abstract:

Chemical-electrical energy conversion and storage are greatly attractive for the development of sustainable energy. Catalytic processes are heavily involved in such energy conversion and storage. Development of high-performance catalyst nanomaterials relies on tuning material structures at nanoscale. This is in particular manifested in the design of catalysts demanding both high activity and durability. Here, a research system will be presented that connects fundamental investigation on well-defined extended surfaces (e.g. single crystal surfaces), extrapolation onto nanocrystals with highly controlled shape and size, exploration of interfacial interaction using novel nanocrystal superlattices as platform, and finally design of high performance catalysts in which all the possible beneficial properties from complex functional structures are implemented. Using recently published results, it will be demonstrated that optimal and fine balanced activity and durability, as well as tunable functionality, can be achieved by carefully tailoring the nanostructure of catalytic nanomaterials.

Keywords: energy, nanomaterials, catalysis, electrocatalysis

Procedia PDF Downloads 206

Authors: Hussain Abdullah Al-Salamin, Elias Ogutu Azariah Tembe

Abstract:

Supply chain (SC) is an operational research (OR) approach and technique which acts as catalyst within central nervous system of business today. Without SC, any type of business is at doldrums, hence entropy. SC is the lifeblood of business today because it is the pivotal hub which provides imperative competitive advantage. The paper present a conceptual framework dubbed as Homomorphic Conceptual Framework for Effective Supply Chain Strategy (HCEFSC).The term homomorphic is derived from abstract algebraic mathematical term homomorphism (same shape) which also embeds the following mathematical application sets: monomorphism, isomorphism, automorphisms, and endomorphism. The HCFESC is intertwined and integrated with wide and broad sets of elements.

Keywords: homomorphism, isomorphism, monomorphisms, automorphisms, epimorphisms, endomorphism, supply chain, operational research (OR)

Procedia PDF Downloads 352

Authors: Farrukh Jamil, Ala'A H. Al-Muhtaseb, Lamya Al-Haj, Mohab A. Al-Hinai

Abstract:

Environmental problems and the security of energy supply have motivated the attention in the expansion of alternatives for fossil based fuels. Biomass has been recognized as a capable resource because it is plentifully available and in principle carbon dioxide neutral. Present study focuses on utilization date seeds oil for synthesizing high value fuels formulations such as green diesel and jet fuel. The hydrodeoxygenation of date seeds oil occurred to be highly efficient at following operating conditions temperature 300°C pressure 10bar with continuous stirring at 500 rpm. Products characterization revealed the efficiency of hydrodeoxygenation by formation of linear hydrocarbons (paraffin) in larger fraction. Based on the type of components in product oil it was calculated that maximum fraction lies within the range of green diesel 72.78 % then jet fuel 28.25 % by using Pt/C catalyst. It can be concluded that waste date seeds oil has potential to be used for obtaining high value products.

Keywords: date seeds, hydrodeoxygenation, paraffin, deoxygenation

Procedia PDF Downloads 243

Authors: Abas Mohsenzadeh, Mina Arya, Kim Bolton

Abstract:

Catalytic combustion of hydrocarbons is an important technology developed to produce energy with minimum pollutant formation. The catalyst plays a key role in this process which operates at lower temperatures compared to conventional flame combustion. The energetics of the direct combustion of hydrocarbons (CH → C + H) on a series of metal surfaces including Ag, Au, Al, Cu, Rh, Pt, Pd, Ni, Fe and Co were investigated using density functional theory (DFT). Brønsted-Evans-Polanyi (BEP) and transition state scaling (TSS) correlations were proposed based on DFT calculations on the Ag, Au, Al, Cu, Rh, Pt and Pd surfaces. These correlations were then used to estimate the energetics on Fe, Ni and Co surfaces. Results showed that the estimated reaction and activation energies by BEP and TSS correlations on Fe, Ni and Co surfaces are in an excellent agreement with those obtained by DFT calculations. Therefore these correlations can be efficiently used to predict energetics of similar reactions on these surfaces without doing computationally costly transition state calculations. It was found that the activation barrier for CH dissociation follows the order Ag ˃ Au ˃ Al ˃ Cu ˃ Pt ˃ Pd ˃ Ni > Co > Rh > Fe. Also, BEP (with R2 value of 0.96) and TSS correlations (with R2 value of 0.99) support the results.

Keywords: BEP, DFT, hydrocarbon combustion, metal surfaces, TSS

Procedia PDF Downloads 236

Authors: Joanna Drzeżdżon

Abstract:

Polyvinyl alcohol and its derivatives such as 2-chloro-2-propen-1-ol have found application in many industries. They are mainly used for the production of adhesives, thickeners and stabilizers of emulsion paints, and surgical threads. Moreover, polyvinyl alcohol derivatives are indispensable reagents in the synthesis of hemiacetals. Polyolefins derived from polyvinyl alcohol are obtained by using catalysts belonging to complex compounds of transition metal ions. The aim of the studies is to the synthesis of a new complex, i.e. dipicolinate oxovanadium(IV) complex with 4,4’-dimethoxy-2,2’-bipyridyl, and to determine its catalytic activities. Moreover, the another aim of the studies was to set conditions for 2-chloro-2-propen-1-ol oligomerization. The catalytic system has been based on the dipicolinate complex of oxovanadium(IV) with 4,4’-dimethoxy-2,2’-bipyridyl and MMAO-12. The results of the studies showed that how a new oxovanadium(IV) complex compound effects on the 2-chloro-2-propen-1-ol oligomerization. Moreover, the results revealed that new catalytic material is a highly active catalyst for the investigated oligomerization.

Keywords: 2-chloro-2-propen-1-ol, oligomerization, dipicolinate, vanadium, methylaluminoxane

Procedia PDF Downloads 107

Authors: Swastik Karmakar, Prasanta Das, Shital K. Chattopadhyay

Abstract:

An efficient synthesis of symmetrical 2, 2′-Di-substituted 3, 3′-bisindolylarylmethanes (BIAMs) having different aryl and hetero-aryl moieties has been developed by Ag(I)-catalyzed indolyzation and a sequential deoxygenative addition involving o-alkynylanilines and aryl/hetero-aryl aldehydes as substrates. Alkyne and carbonyl units could be activated by Ag (I) simultaneously which results in a domino 5-endo-dig indole annulation, addition of C3 of this indole nucleus to the carbonyl carbon in addition to second indole annulation, and its dehydroxylative addition to the same carbonyl carbon to furnish BIAMs in excellent yield. As 3, 3′-bisindolylmethanes (BIMs) are biologically significant scaffolds, this moiety with further substitutions at the indole core could find some important use in medicinal chemistry. The methodology developed is atom-economic and involves more accessible silver salts, which could be useful for large-scale synthesis.

Keywords: alkyne, 3, 3′-Bisindolylarylmethanes, carbonyl, domino, 5-endo-dig indole annulation, silver catalyst

Procedia PDF Downloads 194

Authors: Leila Samiee, Amir Yadegari, Saeedeh Tasharrofi

Abstract:

In the work presented here, nitrogen-doped graphene materials were synthesized and used as metal-free electrocatalysts for oxygen reduction reaction (ORR) under alkaline conditions. Paraphenylenediamine was used as N precursor. The N-doped graphene was synthesized under hydrothermal treatment at 200°C. All the materials have been characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Transmission electron microscopy (TEM) and X-ray photo-electron spectroscopy (XPS). Moreover, for electrochemical evaluation of samples, Rotating Disk electrode (RDE) and Cyclic Voltammetry techniques (CV) were employed. The resulting material exhibits an outstanding catalytic activity for the oxygen reduction reaction (ORR) as well as excellent resistance towards methanol crossover effects, indicating their promising potential as ORR electrocatalysts for alkaline fuel cells.

Keywords: alkaline fuel cell, graphene, metal-free catalyst, paraphenylen diamine

Procedia PDF Downloads 453

Authors: Jovana Petrovic, Biljana Pajin, Ivana Loncarevic, Aleksandar Fistes, Antun Jozinivic, Durdica Ackar, Drago Subaric

Abstract:

Recovery of food wastes and their conversion to economically viable products will play a vital role for the management strategies in the years to come. Apple pomace may be considered as wastes, but they contain considerable amounts of high value reusable materials. Apple pomace, the by-product of apple juice and cider production, is a good source of fibre, particularly insoluble one. The remaining apple pulp contains 12% dry residue, which is half dietary fibre. Another remarkable aspect is its richness in polyphenols, components with antioxidant activity. Apple pomace could be an interesting alternative source for fibre and polyphenols in extruded corn meals. The extruded corn meals with the addition of finely ground apple pomace were prepared (the ratio of corn meal: apple pomace was 85:15 and 70:30). Characterization of the extrudates in terms of determining the chemical composition and colour was performed. The color of samples was measured by MINOLTA Chroma Meter CR-400 (Minolta Co., Ltd., Osaka, Japan) using D 65 lighting, a 2º standard observer angle and an 8-mm aperture in the measuring head. The following CIELab color coordinates were determined: L* – lightness, a* – redness to greenness and b* – yellowness to blueness. Protein content decreased significantly from 7.91% to 5.19% with increase in pomace from 0% to 30%, while total fibre content increase from 3.39% to 16.62%. The apple pomace addition produced extrudates with a significantly lower L* value and significantly higher a* value. This study has been fully supported by the Provincial Secretariat for High Education and Scientific Research of the Government of Autonomous Province of Vojvodina, Republic of Serbia, project 142-451-2483/2017 and the Ministry of Science and Technological Development of the Republic of Serbia (Project no. 31014).

Keywords: apple pomace, chemical composition, colour, extruded corn snack products, food waste recovery

Procedia PDF Downloads 204

Authors: Randa Slatnia

Abstract:

In this study, the nanostructured stable phase identification elaborated by nickel nitrate hyxahydrate and thiourea compounds. After the preparation of the solution (Stirred mixture with methanol as solvent), a deposition of eight layers of this solution on a glass substrate and annealed at 300 °C for energy applications. The annealed sample was analyzed by X-ray Grazing incidence diffraction (GID) with a Bruker D8 Advance diffractometer using Cu Kα1 radiation at 40 kV and 40 mA (1600 W) and Scanning electron microscopy (Thermo Fisher environmental SEM). The results of XRD-GID analysis for the prepared sample showed the formation of an identified stable phase NiS2 and the XRD-GID pattern of the elaborated sample with eight layers prepared solution and annealed show wide and characteristic peaks of the NiS2 with cubic structure (ICDD card no. PDF 01-078-4702). The morphology of the NiS2 thin films confirmed by XRD-GID analysis was investigated by ESEM showed a surface with a uniform and homogeneous distribution nanostructure.

Keywords: nickel sulfide, thin films, XRD, ESEM

Procedia PDF Downloads 64

Authors: Chandan Kundu, Sankar Bhattacharya

Abstract:

A significant disadvantage of fossil fuel energy production is the considerable amount of carbon dioxide (CO₂) released, which is one of the contributors to climate change. Apart from environmental concerns, changing fossil fuel prices have pushed society gradually towards renewable energy sources in recent years. Biomass is a plentiful and renewable resource and a source of carbon. Recent years have seen increased research interest in generating fuels and chemicals from biomass. Unlike fossil-based resources, biomass is composed of lignocellulosic material, which does not contribute to the increase in atmospheric CO₂ over a longer term. These considerations contribute to the current move of the chemical industry from non-renewable feedstock to renewable biomass. This presentation focuses on generating bio-oil and two major platform chemicals that can potentially improve the environment. Thermochemical processes such as pyrolysis are considered viable methods for producing bio-oil and biomass-based platform chemicals. Fluidized bed reactors, on the other hand, are known to boost bio-oil yields during pyrolysis due to their superior mixing and heat transfer features, as well as their scalability. This review and the associated experimental work are focused on the thermochemical conversion of biomass to bio-oil and two high-value platform chemicals, Levoglucosenone (LGO) and 5-Chloromethyl furfural (5-CMF), in a fluidized bed reactor. These two active molecules with distinct features can potentially be useful monomers in the chemical and pharmaceutical industries since they are well adapted to the manufacture of biologically active products. This process took several meticulous steps. To begin, the biomass was delignified using a peracetic acid pretreatment to remove lignin. Because of its complicated structure, biomass must be pretreated to remove the lignin, increasing access to the carbohydrate components and converting them to platform chemicals. The biomass was then characterized by Thermogravimetric analysis, Synchrotron-based THz spectroscopy, and in-situ DRIFTS in the laboratory. Based on the results, a continuous-feeding fluidized bed reactor system was constructed to generate platform chemicals from pretreated biomass using hydrogen chloride acid-gas as a catalyst. The procedure also yields biochar, which has a number of potential applications, including soil remediation, wastewater treatment, electrode production, and energy resource utilization. Consequently, this research also includes a preliminary experimental evaluation of the biochar's prospective applications. The biochar obtained was evaluated for its CO₂ and steam reactivity. The outline of the presentation will comprise the following: Biomass pretreatment for effective delignification Mechanistic study of the thermal and thermochemical conversion of biomass Thermochemical conversion of untreated and pretreated biomass in the presence of an acid catalyst to produce LGO and CMF A thermo-catalytic process for the production of LGO and 5-CMF in a continuously-fed fluidized bed reactor and efficient separation of chemicals Use of biochar generated from the platform chemicals production through gasification

Keywords: biomass, pretreatment, pyrolysis, levoglucosenone

Procedia PDF Downloads 109

Authors: Francisco Vidal Vázquez, Pekka Simell, Christian Frilund, Matti Reinikainen, Ilkka Hiltunen, Tim Böltken, Benjamin Andris, Paolo Piermartini

Abstract:

Carbon capture and utilization (CCU) are one of the key topics in mitigation of CO2 emissions. There are many different technologies that are applied for the production of diverse chemicals from CO2 such as synthetic natural gas, Fischer-Tropsch products, methanol and polymers. Power-to-Gas and Power-to-Liquids concepts arise as a synergetic solution for storing energy and producing value added products from the intermittent renewable energy sources and CCU. VTT is a research and technology development company having energy in transition as one of the key focus areas. VTT has extensive experience in piloting and upscaling of new energy and chemical processes. Recently, VTT has developed and commissioned a Mobile Synthesis Unit (MOBSU) in close collaboration with INERATEC, a spin-off company of Karlsruhe Institute of Technology (KIT, Germany). The MOBSU is a multipurpose synthesis unit for CO2 upgrading to energy carriers and chemicals, which can be transported on-site where CO2 emission and renewable energy are available. The MOBSU is initially used for production of fuel compounds and chemical intermediates by combination of two consecutive processes: reverse Water-Gas Shift (rWGS) and Fischer-Tropsch synthesis (FT). First, CO2 is converted to CO by high-pressure rWGS and then, the CO and H2 rich effluent is used as feed for FT using an intensified reactor technology developed and designed by INERATEC. Chemical equilibrium of rWGS reaction is not affected by pressure. Nevertheless, compression would be required in between rWGS and FT in the case when rWGS is operated at atmospheric pressure. This would also require cooling of rWGS effluent, water removal and reheating. For that reason, rWGS is operated using precious metal catalyst in the MOBSU at similar pressure as FT to simplify the process. However, operating rWGS at high pressures has also some disadvantages such as methane and carbon formation, and more demanding specifications for materials. The main parts of FT module are an intensified reactor, a hot trap to condense the FT wax products, and a cold trap to condense the FT liquid products. The FT synthesis is performed using cobalt catalyst in a novel compact reactor technology with integrated highly-efficient water evaporation cooling cycle. The MOBSU started operation in November 2016. First, the FT module is tested using as feedstock H2 and CO. Subsequently, rWGS and FT modules are operated together using CO2 and H2 as feedstock of ca. 5 Nm3/hr total flowrate. On spring 2017, The MOBSU unit will be integrated together with a direct air capture (DAC) of CO2 unit, and a PEM electrolyser unit at Lappeenranta University of Technology (LUT) premises for demonstration of the SoletAir concept. This would be the first time when synthetic fuels are produced by combination of DAC unit and electrolyser unit which uses solar power for H2 production.

Keywords: CO2 utilization, demonstration, Fischer-Tropsch synthesis, intensified reactors, reverse water-gas shift

Procedia PDF Downloads 272

Authors: M. S. Khurram, S. A. Memon, S. Khan

Abstract:

Bed voidage behavior among different flow regimes for Geldart A, B, and D particles (fluid catalytic cracking catalyst (FCC), particle A and glass beads) of diameter range 57-872 μm, apparent density 1470-3092 kg/m³, and bulk density range 890-1773 kg/m³ were investigated in a gas-solid circulating fluidized bed of 0.1 m-i.d. and 2.56 m-height of plexi-glass. Effects of variables (gas velocity, particle properties, and static bed height) were analyzed on bed voidage. The axial voidage profile showed a typical trend along the riser: a dense bed at the lower part followed by a transition in the splash zone and a lean phase in the freeboard. Bed expansion and dense bed voidage increased with an increase of gas velocity as usual. From experimental results, a generalized model relationship based on inverse fluidization number for dense bed voidage from bubbling to fast fluidization regimes was presented.

Keywords: axial voidage, circulating fluidized bed, splash zone, static bed

Procedia PDF Downloads 264

Authors: Surjyakanta Rana, Sreekantha B. Jonnalagadda

Abstract:

Synthesis of well distributed Pd nanoparticles (3 – 7 nm) on organo amine-functionalized graphene is reported, which demonstrated excellent catalytic activity towards Suzuki coupling reaction. The active material was characterized by X-ray diffraction (XRD), BET surface area, X-ray photoelectron spectra (XPS), Fourier-transfer infrared spectroscopy (FTIR), Raman spectra, Scanning electron microscope (SEM), Transmittance electron microscopy (TEM) analysis and HRTEM. FT-IR revealed that the organic amine functional group was successfully grafted onto the graphene oxide surface. The formation of palladium nanoparticles was confirmed by XPS, TEM and HRTEM techniques. The catalytic activity in the coupling reaction was superb with 100% conversion and 98 % yield and also activity remained almost unaltered up to six cycles. Typically, an extremely high turnover frequency of 185,078 h-1 is observed in the C-C Suzuki coupling reaction using organo di-amine functionalized graphene as catalyst.

Keywords: Di-amine, graphene, Pd nanoparticle, suzuki coupling

Procedia PDF Downloads 351

Authors: A. Alkattib, M. Boumaza

Abstract:

Steam reforming is industrially important as it is incorporated in several major chemical processes including the production of ammonia, methanol, hydrogen and ox alcohols. Due to the strongly endothermic nature of the process, a large amount of heat is supplied by fuel burning (commonly natural gas) in the furnace chamber. Reaction conversions, tube catalyst life, energy consumption and CO2 emission represent the principal factors affecting the performance of this unit and are directly influenced by the high operating temperatures and pressures. This study presents a simulation of the performance of the reforming of methane in a primary reformer, through a developed empirical relation which enables to investigate the effects of operating parameters such as the pressure, temperature, steam to carbon ratio on the production of hydrogen, as well as the fraction of non-converted methane. It appears from this analysis that the exit temperature Te, the operating pressure as well the steam to carbon ratio has an important effect on the reforming of methane.

Keywords: reforming, methane, performance, hydrogen, parameters

Procedia PDF Downloads 197

Authors: Devender Mandala, Paul Watts

Abstract:

Cis-Nucleosides mainly lamivudine (3TC) and emtricitabine (FTC) are an important tool in the treatment of Human immune deficiency virus (HIV), Hepatitis B virus (HBV) and Human T-Lymotropoic virus (HTLV). Lamivudine and emtricitabine are potent nucleoside analog reverse transcriptase inhibitors (nRTI). These two drugs are synthesized by a four-stage process from the starting materials: menthyl glyoxylate hydrate and 1,4-dithane-2,5-diol to produce the 5-hydroxy oxathiolane which upon acetylation with acetic anhydride to yield 5-acetoxy oxathiolane. Then glycosylation of this acetyl product with silyl protected nucleoside to produce the intermediate. The reduction of this intermediates can provide the final targets. Although there are several different methods reported for the synthesis of lamivudine and emtricitabine as a single enantiomer, we required an efficient route, which was suitable for large-scale synthesis to support the development of these compounds. In this process, we successfully prepared the intermediates of lamivudine and emtricitabine without using any solvents and catalyst, thus promoting the green synthesis. All the synthesized compound were confirmed by TLC, GC, Mass, NMR and 13C NMR spectroscopy.

Keywords: emtricitabine, green synthesis, lamivudine, nucleoside

Procedia PDF Downloads 207

Authors: Samira Naghdi, Kyong Yop Rhee

Abstract:

Transfer-free synthesis of graphene on dielectric substrates is highly desirable but remains challenging. Here, by using a thin sacrificial platinum layer as a catalyst, graphene was deposited on a silicon substrate through a simple and transfer-free synthesis method. During graphene growth, the platinum layer evaporated, resulting in direct deposition of graphene on the silicon substrate. In this work, different growth conditions of graphene were optimized. Raman spectra of the produced graphene indicated that the obtained graphene was bilayer. The sheet resistance obtained from four-point probe measurements demonstrated that the deposited graphene had high conductivity. Reflectance spectroscopy of graphene-coated silicon showed a decrease in reflectance across the wavelength range of 200-800 nm, indicating that the graphene coating on the silicon surface had antireflection capabilities.

Keywords: antireflection coating, chemical vapor deposition, graphene, the sheet resistance

Procedia PDF Downloads 163

Authors: Weerachit Pulsawas, Thirasak Rirksomboon

Abstract:

Due to its abundance from catalytic reforming and thermal cracking of naphtha, toluene could become more value-added compound if it is converted into xylenes, particularly p-xylene, via toluene methylation. Attractively, toluene methylation with methanol is an alternative route to produce xylenes in the absence of other hydrocarbon by-products for which appropriate catalyst would be utilized. In this study, HZSM-5 catalysts with Si/Al molar ratio of 100 were synthesized via hydrothermal treatment and modified by either chemical liquid deposition using tetraethyl-orthosilicate or dealumination with steam. The modified catalysts were characterized by several techniques and tested for their catalytic activity in a continuous down-flow fixed bed reactor. Various operating conditions including WHSV’s of 5 to 20 h-1, reaction temperatures of 400 to 500 °C, and toluene-to-methanol molar ratios (T/M) of 1 to 4 were investigated for attaining possible highest p-xylene selectivity. As a result, the catalytic activity of parent HZSM-5 with temperature of 400 °C, T/M of 4 and WHSV of 24 h-1 showed 65.36% in p-xylene selectivity and 11.90% in toluene conversion as demonstrated for 4 h on stream.

Keywords: toluene methylaion, HZSM-5, silylation, dealumination

Procedia PDF Downloads 180

Authors: Sira Suren, Soorathep Kheawhom

Abstract:

This work investigates the development of a high energy density zinc-air battery. Printed and flexible thin film zinc-air battery with an overall thickness of about 350 μm was fabricated by an inexpensive screen-printing technique. Commercial nano-silver ink was used as both current collectors and catalyst layer. Carbon black ink was used to fabricate cathode electrode. Polypropylene membrane was used as the cathode substrate and separator. 9 M KOH was used as the electrolyte. A mixture of Zn powder, ZnO, and Bi2O3 was used to prepare the anode electrode. The suitable concentration of Bi2O3 and types of binders (styrene-butadiene and sodium silicate) were investigated. Results showed that battery using 20% Bi2O3 and sodium silicate binder provided the best performance. The open-circuit voltage and energy density observed were 1.59 V and 690 Wh/kg, respectively. When the battery was discharged at 20 mA/cm2, the potential voltage observed was 1.3 V. Furthermore, the battery was tested for its flexibility. Upon bending, no significant loss in performance was observed.

Keywords: flexible, printed battery, screen printing, Zn-air

Procedia PDF Downloads 253

Authors: Prince Dacosta Aboagye, Ayyoob Sharifi

Abstract:

Cities respond to climate concerns mainly through their climate action plans (CAPs). A comprehensive content analysis of the dynamics in existing urban CAPs is not well represented in the literature. This literature void presents a difficulty in appreciating the strengths and weaknesses of urban CAPs. Here, we perform a qualitative content analysis (QCA) on CAPs from 278 cities worldwide and use text-mining tools to map and visualize the relevant data. Our analysis showed a decline in the number of CAPs developed and published following the global COVID-19 lockdown period. Evidently, megacities are leading the deep decarbonisation agenda. We also observed a transition from developing mainly mitigation-focused CAPs pre-COP21 to both mitigation and adaptation CAPs. A lack of inclusiveness in local climate planning was common among European and North American cities. The evidence is a catalyst for understanding the trends in existing urban CAPs to shape future urban climate planning.

Keywords: urban, climate action plans, strengths, weaknesses

Procedia PDF Downloads 72

Authors: Mohamed El Moctar Abeidi

Abstract:

The indazole derivatives exhibit a wide spectrum of biological activities. They are known for their anti-tumor, antiplatelet, anti-viral, anti-microbial, anti-inflammatory, anti-leishmania and even anti-spermatogen. As part of our research on the synthesis of a number of heterocycles capable of exhibiting a biological and pharmacological property, due to our ongoing interest in the development of a simple and low-cost procedure for obtaining heterocyclic compounds that may have an interest for medicinal purposes. We present in this work the synthesis of 6-nitro-indazoles derivatives, using two different methods. the first method is the alkylation of Nitroindazole by two different alkylating agents under the conditions of solid/liquid phase transfer catalysis in N, N-dimethylformamide (DMF) in the presence of potassium carbonate (K₂CO₃) as a base, and tetra-n-butylammonium bromide (BTBA) as a catalyst. While the other method is the 1,3-dipolar cycloaddition, in this case, we have undertaken the preparation of bi-heterocyclic containing the 6-nitroindazole associate with group of isoxazoline, isoxazole or 1,2,3-Triazole under normal conditions and, under the catalytic conditions of the click chemistry we were also able to determine the structures without any ambiguity by the ¹H and ¹³C NMR.

Keywords: indazole, 6-nitroindazole, isoxazole, 1, 2, 3-Triazole

Procedia PDF Downloads 127

Authors: Najme lari, Shahrokh Ahangarani, Ali Shanaghi

Abstract:

Multilayer structure of thin films by the sol–gel process attracts great attention for antireflection applications. In this paper, antireflective nanometric multilayer SiO2-TiO2 films are formed on both sides of the glass substrates by combining the sol–gel method and the dip-coating technique. SiO2 and TiO2 sols were prepared using tetraethylorthosilicate (TEOS) and tetrabutylorthotitanate (TBOT) as precursors and also nitric acid as catalyst. Prepared coatings were investigated by Field-emission scanning electron microscope (FE-SEM), Fourier-transformed infrared spectrophotometer (FT-IR) and UV–visible spectrophotometer. After evaluation, all of SiO2 top layer coatings showed excellent antireflection in the wavelength range of 400-800 nm where the transmittance of glass substrate is significantly lower. By increasing the number of double TiO2-SiO2 layers, the transmission of the coated glass increases due to applied multilayer coating properties. 6-layer sol–gel TiO2-SiO2 shows the highest visible transmittance about 99.25% at the band of 550-650 nm.

Keywords: thin films, optical properties, sol-gel, multilayer

Procedia PDF Downloads 401

Authors: Fatima Ammari, Meriem Chenouf

Abstract:

Synthesis of gold nanoparticles (AuNPs) has attracted much attention since the pioneering discovery of the high catalytic activity of supported gold nanoparticles in the reaction of CO oxidation at low temperature. In this research field, we used montmorillonite pre-acidified under gentle conditions for AuNPs stabilization; using different loading percentage 1, 2 and 5%. The gold nanoparticles were obtained using chemical reduction method using NaBH4 as reductant agent. The obtained gold nanoparticles stabilized in acid-activated montmorillonite were used as catalysts for reduction of 4-nitrophenol to aminophenol with sodium borohydride at room temperature The UV-Vis results confirm directly the gold nanaoparticles formation. The XRD N2 adsorption and MET results showed the formation of gold nanoparticles in the pores of preacidified montmorillonite with an average size of 5.7nm. The reduction reaction of 4-nitrophenol into 4-aminophenol with NaBH4 catalyzed by Au°-montmorillonite catalyst exhibits remarkably a high activity; the reaction was completed within 4.5min.

Keywords: gold, acid-activated montmorillonite, nanoparticles, 4-nitrophenol

Procedia PDF Downloads 362

Authors: Manju Verma, Parag A. Deshpande

Abstract:

Electronic structure calculations of hydrogen terminated metal-porphyrin graphene were carried out to explore the catalytic activity for CO2 hydration reaction. A ruthenium atom was substituted in place of carbon atom of graphene and ruthenium chelated carbon atoms were replaced by four nitrogen atoms in metal-porphyrin graphene system. Ruthenium atom created the active site for CO2 hydration reaction. Ruthenium-porphyrin graphene followed the mechanism of carbonic anhydrase enzyme for CO2 conversion to HCO3- ion. CO2 hydration reaction over ruthenium-porphyrin graphene proceeded via the elementary steps: OH- formation from H2O dissociation, CO2 bending in presence of nucleophilic attack of OH- ion, HCO3- ion formation from proton migration, HCO3- ion desorption by H2O addition. Proton transfer to yield HCO3- ion was observed as a rate limiting step from free energy landscape.

Keywords: ruthenium-porphyrin graphene, CO2 hydration, carbonic anhydrase, heterogeneous catalyst, density functional theory

Procedia PDF Downloads 230

Authors: Kumaresh Selvakumar, Man Young Kim

Abstract:

Selective catalytic reduction (SCR) converts the nitrogen oxides with the aid of a catalyst by adding aqueous urea into the exhaust stream. In this work, the urea water droplets are sprayed over the exhaust gases by treating with Lagrangian particle tracking. The evaporation of ammonia from a single droplet of urea water solution is investigated computationally by convection-diffusion controlled model. The conversion to ammonia due to thermolysis of urea water droplets is measured downstream at different sections using finite rate/eddy dissipation model. In this paper, the mixer installed at the upstream enhances the distribution of ammonia over the entire domain which is calculated for different time steps. Calculations are made within the respective duration such that the complete decomposition of urea is possible at a much shorter residence time.

Keywords: convection-diffusion controlled model, lagrangian particle tracking, selective catalytic reduction, thermolysis

Procedia PDF Downloads 382

Authors: Cristina Opris, Bogdan Cojocaru, Madalina Tudorache, Simona M. Coman, Vasile I. Parvulescu, Camelia Bala, Bahir Duraki, Jeroen A. Van Bokhoven

Abstract:

The tremendous achievements in the development of the society concretized by more sophisticated materials and systems are merely based on non-renewable resources. Consequently, after more than two centuries of intensive development, among others, we are faced with the decrease of the fossil fuel reserves, an increased impact of the greenhouse gases on the environment, and economic effects caused by the fluctuations in oil and mineral resource prices. The use of biomass may solve part of these problems, and recent analyses demonstrated that from the perspective of the reduction of the emissions of carbon dioxide, its valorization may bring important advantages conditioned by the usage of genetic modified fast growing trees or wastes, as primary sources. In this context, the abundance and complex structure of lignin may offer various possibilities of exploitation. However, its transformation in fuels or chemicals supposes a complex chemistry involving the cleavage of C-O and C-C bonds and altering of the functional groups. Chemistry offered various solutions in this sense. However, despite the intense work, there are still many drawbacks limiting the industrial application. Thus, the proposed technologies considered mainly homogeneous catalysts meaning expensive noble metals based systems that are hard to be recovered at the end of the reaction. Also, the reactions were carried out in organic solvents that are not acceptable today from the environmental point of view. To avoid these problems, the concept of this work was to investigate the synthesis of superparamagnetic core shell catalysts for the fragmentation of lignin directly in the aqueous phase. The magnetic nanoparticles were covered with a nanoshell of an oxide (niobia) with a double role: to protect the magnetic nanoparticles and to generate a proper (acidic) catalytic function and, on this composite, cobalt nanoparticles were deposed in order to catalyze the C-C bond splitting. With this purpose, we developed a protocol to prepare multifunctional and magnetic separable nano-composite Co@Nb2O5@Fe3O4 catalysts. We have also established an analytic protocol for the identification and quantification of the fragments resulted from lignin depolymerization in both liquid and solid phase. The fragmentation of various lignins occurred on the prepared materials in high yields and with very good selectivity in the desired fragments. The optimization of the catalyst composition indicated a cobalt loading of 4wt% as optimal. Working at 180 oC and 10 atm H2 this catalyst allowed a conversion of lignin up to 60% leading to a mixture containing over 96% in C20-C28 and C29-C37 fragments that were then completely fragmented to C12-C16 in a second stage. The investigated catalysts were completely recyclable, and no leaching of the elements included in the composition was determined by inductively coupled plasma optical emission spectrometry (ICP-OES).

Keywords: superparamagnetic core-shell catalysts, environmental production of fuels, renewable lignin, recyclable catalysts

Procedia PDF Downloads 314

Authors: Najme Lari, Shahrokh Ahangarani, Ali Shanaghi

Abstract:

Multilayer structure of thin films by the sol–gel process attracts great attention for antireflection applications. In this paper, antireflective nanometric multilayer SiO2-TiO2 films are formed on both sides of the glass substrates by combining the sol–gel method and the dip-coating technique. SiO2 and TiO2 sols were prepared using tetraethylorthosilicate (TEOS) and tetrabutylorthotitanate (TBOT) as precursors and nitric acid as catalyst. Prepared coatings were investigated by Field-emission scanning electron microscope (FE-SEM), Fourier-transformed infrared spectrophotometer (FT-IR) and UV–visible spectrophotometer. After evaluation, all of SiO2 top layer coatings showed excellent antireflection in the wavelength range of 400-800 nm where the transmittance of glass substrate is significantly lower. By increasing the number of double TiO2-SiO2 layers, the transmission of the coated glass increases due to applied multilayer coating properties. 6-layer sol–gel TiO2-SiO2 shows the highest visible transmittance about 99.25% at the band of 550-650 nm.

Keywords: thin films, optical properties, sol-gel, multilayer

Procedia PDF Downloads 383

Authors: R. Osada, S. Ogata, T. Segawa

Abstract:

Dielectric barrier discharge plasma actuators (DBD-PAs) have been developed for active flow control devices. However, it is necessary to reduce ozone produced by DBD toward practical applications using DBD-PAs. In this study, variations of ozone concentration, flow velocity, power consumption were investigated by changing exposed electrodes of DBD-PAs. Two exposed electrode prototypes were prepared: span-type with exposed electrode width of 0.1 mm, and normal-type with width of 5 mm. It was found that span-type shows lower power consumption and higher flow velocity than that of normal-type at V_p-p = 4.0-6.0 kV. Ozone concentration of span-type higher than normal-type at V_p-p = 4.0-8.0 kV. In addition, it was confirmed that catalyst located in downstream from the exposed electrode can reduce ozone concentration between 18 and 42% without affecting the induced flow.

Keywords: dielectric barrier discharge plasma actuators, ozone diffusion, PIV measurement, power consumption

Procedia PDF Downloads 223

Authors: Jafar Khan Kasi, Ajab Khan Kasi, Muzamil Bokhari

Abstract:

Carbon nanotube is one of the most attractive materials for the potential applications of nanotechnology due to its excellent mechanical, thermal, electrical and optical properties. In this paper we report a supercapacitor made of nickel foil electrodes, coated with multiwall carbon nanotubes (MWCNTs) thin film using electrophoretic deposition (EPD) method. Chemical vapor deposition method was used for the growth of MWCNTs and ethanol was used as a hydrocarbon source. High graphitic multiwall carbon nanotube was found at 750 C analyzing by Raman spectroscopy. We observed the electrochemical performance of supercapacitor by cyclic voltammetry. The electrodes of supercapacitor fabricated from MWCNTs exhibit considerably small equivalent series resistance (ESR), and a high specific power density. Electrophoretic deposition is an easy method in fabricating MWCNT electrodes for high performance supercapacitor.

Keywords: carbon nanotube, chemical vapor deposition, catalyst, charge, cyclic voltammetry

Procedia PDF Downloads 534