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Showing records 1 to 25 of 299. [First] Page: 1 2 3 4 5 Last
Improved Removal of Quinoline from Wastewater Using Coke Powder with Inorganic Ions
Lei Wang, Qieyuan Gao, Zhipeng Li, Yongtian Wang
March 25, 2020 (v1)
Subject: Materials
Keywords: Adsorption, coke powder, inorganic ions, quinoline, wastewater treatment
In this paper, laboratory batch adsorption tests were performed to study the adsorption behavior of coke powder in a quinoline aqueous solution with the absence and presence of inorganic ions (K+ and Ca2+). Adsorption isotherms, thermodynamic parameters, and kinetic models were used to understand the sorption mechanism, and zeta potential measurements were performed to elucidate the effect of the inorganic ions on the adsorption. The results showed that coke powder exhibited a reasonably good adsorption performance due to its pore structure and surface characteristics, and the presence of K+ and Ca2+ could further improve the adsorption. Without inorganic ions, the adsorption capacity of coke powder for quinoline and the removal efficiency of quinoline were 1.27 mg/g and 84.90%, respectively. At the ion concentration of 15 mmol, the adsorption capacity of coke powder and quinoline removal efficiency in the presence of K+ reached 1.38 mg/g and 92.02%, respectively, whereas those in the... [more]
Enhancing the Pore Properties and Adsorption Performance of Cocoa Pod Husk (CPH)-Derived Biochars via Post-Acid Treatment
Wen-Tien Tsai, Chien-Hung Hsu, Yu-Quan Lin, Chi-Hung Tsai, Wen-Shing Chen, Yao-Tsung Chang
March 12, 2020 (v1)
Subject: Materials
Keywords: adsorption performance, biochar, cocoa pod husk, energy dispersive X-ray spectroscopy, Fourier Transform infrared spectroscopy, pore property
In this work, the cocoa pod husk (CPH) was converted into biochar products at higher carbonization temperatures (i.e., 400−800 °C). The pore and chemical properties of the resulting biochars and its post-leaching biochars by acid washing, including specific surface area, total pore volume, pore size distribution, true density, and scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS) and Fourier Transform infrared spectroscopy (FTIR) were studied. Based on the pore properties, pyrolysis temperature at around 800 °C seemed to have the most profound impact on the pore development for producing biochar, where its Brunauer−Emmet−Teller (BET) surface area is 101 m2/g. More noticeably, more pores in the CPH-based biochar could be significantly created during the acid-washing, resulting in an increase of BET surface area from 101 to 342 m2/g. According to the data on the EDS and FTIR, the resulting biochars seemed to have oxygen-containing functional groups on the surfac... [more]
Removal of Agrochemicals from Waters by Adsorption: A Critical Comparison among Humic-Like Substances, Zeolites, Porous Oxides, and Magnetic Nanocomposites
Antonello Marocco, Gianfranco Dell’Agli, Filomena Sannino, Serena Esposito, Barbara Bonelli, Paolo Allia, Paola Tiberto, Gabriele Barrera, Michele Pansini
March 12, 2020 (v1)
Subject: Materials
Keywords: Adsorption, agrochemicals, humic-like substances, magnetic nanocomposites, porous oxides, zeolites
The use of humic-like substances, zeolites, various porous oxides (i.e., Al, Fe, or Si oxides), and magnetic nanocomposites in the adsorption of agrochemicals from water was critically reviewed. Firstly, the adsorbents were characterized from the structural, textural, and physico-chemical points of view. Secondly, the fundamental aspects of the adsorption of various agrochemicals on the solids (dependence on pH, kinetics, and isotherm of adsorption) were studied and interpreted on the basis of the adsorbent features. Thirdly, iterative processes of agrochemical removal from water by adsorption on the reported solids were described. In particular, in some cases the residual concentration of agrochemicals in water was lower than the maximum concentration of agrochemicals that the Italian regulations allow to be released in wastewater, surface waters, or sink water.
Prickly Pear Seed Oil by Shelf-Grown Cactus Fruits: Waste or Maste?
Vassilios K. Karabagias, Ioannis K. Karabagias, Ilias Gatzias, Anastasia V. Badeka
March 12, 2020 (v1)
Subject: Materials
Keywords: antioxidant activity, FAs, phenolics, PPSO, volatiles
The chemical composition and properties of seed oils have attracted researchers nowadays. By this meaning, the physicochemical and bioactivity profile of prickly pear seed oil (PPSO) (a product of prickly pear fruits waste) were investigated. Seeds of shelf-grown cactus fruits (Opuntia ficus indica L.) were subjected to analysis. Moisture content (gravimetric analysis), seed content (gravimetric analysis), oil yield (Soxhlet extraction/gravimetric analysis), volatile compounds (HS-SPME/GC-MS), fatty acids profile (GC-FID), in vitro antioxidant activity (DPPH assay), and total phenolic content (Folin-Cioacalteu assay) were determined. Results showed that prickly pear seeds had a moisture content of 6.0 ± 0.1 g/100 g, whereas the oil yield ranged between 5.4 ± 0.5 g/100 g. Furthermore, the PPSO had a rich aroma because of acids, alcohols, aldehydes, esters, hydrocarbons, ketones, and other compounds, with the major volatiles being 2-propenal, acetic acid, pentanal, 1-pentanol, hexanal, 2... [more]
Mass Spectral Fragmentation of Pelargonium graveolens Essential Oil Using GC−MS Semi-Empirical Calculations and Biological Potential
Mamoun S. M. Abd El-Kareem, Mohamed A. Rabbih, Hosam O. Elansary, Fahed A. Al-Mana
March 12, 2020 (v1)
Subject: Materials
Keywords: antibacterial, antifungal, essential oils, gas chromatography-mass spectrometry, Pelargonium graveolens, semi-empirical calculations
The volatile constituents of the essential oil of local Pelargonium graveolens growing in Egypt was investigated by gas chromatography−mass spectrometry (GC−MS), and the main constituents were citronellol (27.67%), cis-Menthone (10.23%), linalool (10.05%), eudesmol (9.40%), geraniol formate 6.87%, and rose oxide (5.77%), which represent the major components in the obtained GC total ion chromatogram. The structural determination of the main constitutes based on their electron ionization mass spectra have been investigated. The MS of these compounds are absolutely identical in mass values of peaks of fragment ions, where their relative intensities have minor differences. In the spectra of all studied compounds, the observed characteristic ions were [M-H2O]+ and [M-CH3]+. The latter has a structure with m/z 69, 83. Different quantum parameters were obtained using Modified Neglect of Diatomic Overlap (MNDO) semi-empirical method as total energy, binding energy, heat of formations, ionizati... [more]
Identification and Quantification of Volatile Compounds Found in Vinasses from Two Different Processes of Tequila Production
Elizabeth Rodríguez-Félix, Silvia Maribel Contreras-Ramos, Gustavo Davila-Vazquez, Jacobo Rodríguez-Campos, Erika Nahomy Marino-Marmolejo
February 24, 2020 (v1)
Subject: Materials
Keywords: dark fermentative, inhibitors, stillage, tequila, volatile compounds
Vinasses are the main byproducts of ethanol distillation and distilled beverages worldwide and are generated in substantial volumes. Tequila vinasses (TVs) could be used as a feedstock for biohydrogen production through a dark fermentative (DF) process due to their high content of organic matter. However, TV components have not been previously assayed in order to evaluate if they may dark ferment. This work aimed to identify and quantify volatile compounds (VC) in TV and determine if the VC profile depends upon the type of production process (whether the stems were initially cooked or not). TVs were sampled from 3 agave stems with a not-cooking (NC) process, and 3 agave stems with a cooking (C) process, and volatile compounds were determined by gas chromatography coupled with mass spectrometry (GC⁻MS). A total of 111 volatile compounds were identified, the TV from the cooking process (C) showed the higher presence of furanic compounds (furfural and 5-(hydroxymethyl) furfural) and organ... [more]
Review of Research Progress on the Electrical Properties and Modification of Mineral Insulating Oils Used in Power Transformers
Xiaobo Wang, Chao Tang, Bo Huang, Jian Hao, George Chen
February 24, 2020 (v1)
Subject: Materials
Keywords: electrical properties, mineral insulating oil, molecular dynamics simulation, power transformer
In November 2017, the first ±1100 kV high-voltage direct-current power transformer in the world, which was made by Siemens in Nurnberg, passed its type test. Meanwhile, in early 2017, a ±1000 kV ultra-high voltage (UHV) substation was officially put into operation in Tianjin, China. These examples illustrate that the era of UHV power transmission is coming. With the rapid increase in power transmission voltage, the performance requirements for the insulation of power transformers are getting higher and higher. The traditional mineral oils used inside power transformers as insulating and cooling agents are thus facing a serious challenge to meet these requirements. In this review, the basic properties of traditional mineral insulating oil are first introduced. Then, the variation of electrical properties such as breakdown strength, permittivity, and conductivity during transformer operation and aging is summarized. Next, the modification of mineral insulating oil is investigated with a... [more]
Polyetherimide-Montmorillonite Nano-Hybrid Composite Membranes: CO2 Permeance Study via Theoretical Models
Asif Jamil, Oh Pei Ching, Muhammad Naqvi, Hafiza Aroosa Aslam Khan, Salman Raza Naqvi
February 12, 2020 (v1)
Subject: Materials
Keywords: bharadwaj, CO2 permeation, composite membranes, hollow fibre, montmorillonite, polyetherimide
The incorporation of aminolauric acid modified montmorillonite (f-MMT) in polyetherimide (PEI) has been implemented to develop hollow fibre nano-hybrid composite membranes (NHCMs) with improved gas separation characteristics. The aforementioned characteristics are caused by enhanced f-MMT spatial dispersion and interfacial interactions with PEI matrix. In this study, existing gas permeation models such as, Nielsen, Cussler, Yang−Cussler, Lape−Cussler and Bharadwaj were adopted to estimate the dispersion state of f-MMT and to predict the CO2 permeance in developed NHCMs. It was found out that the average aspect ratio estimated was 53, with 3 numbers of stacks per unit tactoid, which showed that the intercalation f-MMT morphology is the dominating dispersion state of filler in PEI matrix. Moreover, it was observed that Bharadwaj model showed the least average absolute relative error (RE) values till 3 wt. % f-MMT loading in the range of ±10 for a pressure range of 2 to 10 bar. Hence, Bha... [more]
Plasmonic-Active Nanostructured Thin Films
Jay K. Bhattarai, Md Helal Uddin Maruf, Keith J. Stine
February 12, 2020 (v1)
Subject: Materials
Keywords: biosensing, gold nanostructures, lithography, localized surface plasmon resonance (LSPR), nanofabrication, nanohole array, plasmonics, thin film
Plasmonic-active nanomaterials are of high interest to scientists because of their expanding applications in the field for medicine and energy. Chemical and biological sensors based on plasmonic nanomaterials are well-established and commercially available, but the role of plasmonic nanomaterials on photothermal therapeutics, solar cells, super-resolution imaging, organic synthesis, etc. is still emerging. The effectiveness of the plasmonic materials on these technologies depends on their stability and sensitivity. Preparing plasmonics-active nanostructured thin films (PANTFs) on a solid substrate improves their physical stability. More importantly, the surface plasmons of thin film and that of nanostructures can couple in PANTFs enhancing the sensitivity. A PANTF can be used as a transducer for any of the three plasmonic-based sensing techniques, namely, the propagating surface plasmon, localized surface plasmon resonance, and surface-enhanced Raman spectroscopy-based sensing techniqu... [more]
Physicochemical Properties of Guava Snacks as Affected by Drying Technology
Yuri M. Leiton-Ramírez, Alfredo Ayala-Aponte, Claudia I. Ochoa-Martínez
February 12, 2020 (v1)
Subject: Materials
Keywords: convective drying, guava, lyophilization, properties, Refractance Window®
Guava is widely consumed because of its agro-industrial use, and its antioxidant properties attributed to vitamin C and carotenoids content. However, it has a short shelf life. Guava has been dried by atomization, fluidized bed, lyophilization (FD) and convective drying (CD). CD requires long operation times and the product characteristics are not desirable. In contrast, FD produces high quality products, but requires long processing times, high energy consumption and high operation costs. As an alternative, the Refractance Window® (RW) drying is relatively simple and cheap technique. The objective of this study was to compare the effect of CD, FD and RW techniques, on the moisture content, water activity, color, porosity, volume change, vitamin C and carotenoids content in guava samples. The samples dried by RW required less time to reduce the moisture content and exhibited smaller changes in color than CD or FD. There were greater losses of carotenoids and vitamin C when drying by CD... [more]
Ultrasonically Induced Sulfur-Doped Carbon Nitride/Cobalt Ferrite Nanocomposite for Efficient Sonocatalytic Removal of Organic Dyes
Surabhi Kamal, Guan-Ting Pan, Siewhui Chong, Thomas Chung-Kuang Yang
February 12, 2020 (v1)
Subject: Materials
Keywords: carbon nitride, catalyst, cobalt ferrite, nanocomposite, organic dye, SCN/CoFe2O4, sonocatalyst, ultrasound, ultrasound-assisted degradation
The sulfur-doped carbon nitride/cobalt ferrite nanocomposite (SCN/CoFe2O4) was prepared via ultrasonication and studied for the sonocatalytic degradation of wastewater organic dye pollutants including methylene blue, rhodamine B, and Congo red. The X-ray photoelectron spectroscopy confirmed the presence and atomic ratios of S, C, N, Co, Fe, and O elements and their corresponding bonds with Co2+ and Fe3+ cations. The nanocomposite was found to have aggregated nanoparticles on a sheet-like structure. The bandgap energy was estimated to be 1.85 eV. For the sonocatalytic degradation of 25-ppm methylene blue at 20 kHz, 1 W and 50% amplitude, the best operating condition was determined to be 1 g/L of catalyst dosage and 4 vol % of hydrogen peroxide loading. Under this condition, the sonocatalytic removal efficiency was the highest at 96% within a reaction period of 20 min. SCN/CoFe2O4 outperformed SCN and CoFe2O4 by 2.2 and 6.8 times, respectively. The SCN/CoFe2O4 nanocomposite was also foun... [more]
Preparation of Sawdust-Filled Recycled-PET Composites via Solid-State Compounding
Rula M. Allaf, Esraa Albarahmieh, Mohammad Futian
February 12, 2020 (v1)
Subject: Materials
Keywords: cryomilling, film, PET, recycling, wood plastic composite
Recently, consumer markets have shown great interest in sustainable products. Considerable research efforts are headed towards developing biodegradable and recyclable polymers and composites. In this study, the fabrication of a wood−plastic composite (WPC) via solid state compounding has been examined. Polyethylene terephthalate (PET) and wood sawdust waste as major components of waste and challenging materials for the manufacturing of WPCs have been explored. Furthermore, the addition of poly(ε-caprolactone) as a biodegradable plasticizing agent was investigated. Composite powders were prepared by cryogenic solid-state milling (cryomilling) according to a statistical mixture design. Mechanical and water absorption properties were inspected on film samples obtained by hot pressing. Different formulations resulted in a variety of colors, textures, water interactions and mechanical properties. A sawdust content of approximately 25 vol.% was optimal for the best combination of properties.... [more]
Influence of Carbon Nanosheets on the Behavior of 1,2-Dipalmitoyl-sn-glycerol-3-phosphocholine Langmuir Monolayers
Ruth Muñoz-López, Eduardo Guzmán, Maria Mercedes Velázquez, Laura Fernández-Peña, María Dolores Merchán, Armando Maestro, Francisco Ortega, Ramón G. Rubio
February 12, 2020 (v1)
Subject: Materials
Keywords: carbon nanosheets, dilational rheology, Langmuir monolayer, lipids, lung surfactant, particles, pollution, toxicity
Carbon nanomaterials are widespread in the atmospheric aerosol as a result of the combustion processes and their extensive industrial use. This has raised many question about the potential toxicity associated with the inhalation of such nanoparticles, and its incorporation into the lung surfactant layer. In order to shed light on the main physical bases underlying the incorporation of carbon nanomaterials into lung surfactant layers, this work has studied the interaction at the water/vapor interface of carbon nanosheets (CN) with Langmuir monolayers of 1,2-Dipalmitoyl-sn-glycerol-3-phosphocholine (DPPC), with this lipid being the main component of lung surfactant layers and responsible of some of the most relevant features of such film. The incorporation of CN into DPPC Langmuir monolayers modifies the lateral organization of the DPPC at the interface, which is explained on the basis of two different effects: (i) particles occupy part of the interfacial area, and (ii) impoverishment of... [more]
Drastic Microwave Heating of Percolated Pt Metal Nanoparticles Supported on Al2O3 Substrate
Taishi Ano, Masato M. Maitani, Yuka Sato, Shuntaro Tsubaki, Yuji Wada
February 12, 2020 (v1)
Subject: Materials
Keywords: conductive network, metal nanoparticles, microwave heating, percolated structure, supported catalyst system
Microwave (MW) heating of supported metal nanoparticles (NPs) presents attractive effects on catalysis such as the rapid heating processes and the enhancement of the reaction rate. Improving the heating property of the NPs, which act as the catalytic active sites, the MW effects will become more significant. Here we show a systematic study about the supported Pt NPs structure to improve the MW heating property. We found that the drastic heating was induced by a percolated Pt NPs structure, where the conduction electrons move around in the two-dimensional network. On the other hand, no heating was observed in an isolated Pt NPs system with the confined electrons. We conclude that the percolation of the Pt NPs giving the network structure is one of the important key factors for the efficient MW heating. The optimized Pt NPs catalyst leads to the dramatic MW effects on catalytic reactions.
Assessment of the Use of Natural Extracted Dyes and Pancreatin Enzyme for Dyeing of Four Natural Textiles: HPLC Analysis of Phytochemicals
Mohamed Z. M. Salem, Ibrahim H. M. Ibrahim, Hayssam M. Ali, Hany M. Helmy
February 12, 2020 (v1)
Subject: Materials
Keywords: color strength, flavonoid compounds, natural dyes, natural fibers, pancreatin enzyme, phenolic compounds
In the present study, four natural textiles (cotton, linen, wool, and silk) were dyed with 14 naturally extracted dyes, and pancreatin enzyme was used in the dyeing process. The effects of pancreatin enzyme and its buffer on naturally dyed textile samples were evaluated. Two concentrations of pancreatin enzyme and buffer were used as pretreatments for dyed textiles. Proteinic fabrics showed the highest relative color strength (RCS) values of 137.23% and 132.2% when the pancreatin enzyme was applied on wool and silk dyed with pomegranate skin and bloodroot at concentrations A and B, respectively. Linen fiber dyed with catechu tree showed the highest total color difference (TCD) values with buffer (6.83) and pancreatin enzyme A (5.7) and B (6.3). This shows that there were no side effects of the pancreatin enzyme on the studied dyed textiles. By high-performance liquid chromatography (HPLC) analysis, the root extract from madder showed the presence of salicylic acid (1758.91 mg/kg extrac... [more]
Leaching Behaviors of Impurities in Titanium-Bearing Electric Furnace Slag in Sulfuric Acid
Wenlin Nie, Shuming Wen, Dan Liu, Qian Zhang, Junbo Liu, Qicheng Feng
February 12, 2020 (v1)
Subject: Materials
Keywords: impurities, leaching, sulfuric acid, titanium-bearing electric furnace slag, vanadium titanomagnetite
Titanium-bearing electric furnace slag (TEFS) was prepared from vanadium titanomagnetite and leached with sulfuric acid. The Ti leaching rate of vanadium titanomagnetite TEFS is significantly lower than that of ilmenite TEFS. The impurity content in vanadium titanomagnetite TEFS is higher than that in ilmenite TEFS. This might be one of the main factors resulting in the low leaching rate of Ti, so the leaching behaviors of various impurities under different conditions (temperature, acid/solid weight ratio, particle size, and initial sulfuric acid concentration) were investigated. The following trends were observed under different leaching conditions: The leaching rate of Fe increased rapidly and reached equilibrium quickly, that of Si increased quickly in the early stage and then decreased in the later stage, that of Ca increased initially and reached equilibrium later, and the leaching rates of Mg and Al increased gradually until the equilibrium was reached. The leaching rate of Fe wa... [more]
Microwave Heating Behavior in SiC Fiber-MO2 Mixtures (M = Ce, Zr)—Selective Heating of Micrometer-Sized Fibers Facilitated by ZrO2 Powder
Keiichiro Kashimura, Jun Fukushima, Tomoaki Namioka, Takashi Fujii, Hirotsugu Takizawa, Hideoki Fukushima
February 12, 2020 (v1)
Subject: Materials
Keywords: anomalous heating behavior, microwave heating, selective heating, silicon carbide fibers, ZrO2
SiC fiber-MO2 (M = Ce, Zr) mixtures with various compositions were heated by applying an 80 W microwave electric field, to investigate their heating rate, maximum temperature, and dielectric constant. For the SiC fiber-CeO2 mixture, all three parameters continued to increase as the weight ratio of the SiC fiber increased; in contrast, for the SiC fiber-ZrO2 mixture, these parameters reached a maximum value at a certain composition. A thermal gradient of 500 °C was observed at a microlevel in the SiC fiber-ZrO2 mixture, and hot spots were located in regions with a certain composition. This result not only contributes to designing a novel good microwave absorber but also presents new aspects with regard to high-temperature microwave processing, including the mechanism behind the high-temperature gradients on the order of micrometers as well as engineering applications that utilize these high-temperature gradients.
Enhancing the Removal of Sb (III) from Water: A Fe3O4@HCO Composite Adsorbent Caged in Sodium Alginate Microbeads
Jun Zhang, Renjian Deng, Bozhi Ren, Mohammed Yaseen, Andrew Hursthouse
February 12, 2020 (v1)
Subject: Materials
Keywords: Adsorption, antimony-containing wastewater, ferriferous oxide polishing sludge, microbeads, sodium alginate
To remove antimony (Sb) ions from water, a novel composite adsorbent was fabricated from ferriferous oxide and waste sludge from a chemical polishing process (Fe3O4@HCO) and encapsulated in sodium alginate (SAB). The SAB adsorbent performed well with 80%−96% removal of Sb (III) ions within a concentration range of 5−60 mg/L. The adsorption mechanism of Sb (III) was revealed to be the synergy of chemisorption (ion exchange) and physisorption (diffusion reaction). The adsorption isotherms and kinetics conformed to the Langmuir isotherm and the pesudo-second-order kinetic model. Both initial pH and temperature influenced the adsorption performance with no collapse of microbeads within solution pH range 3−7. Most importantly for practical applications, these microspheres can be separated and recovered from aqueous solution by a magnetic separation technology to facilitate large-scale treatment of antimony-containing wastewater.
Investigations on Novel Ternary Green Polymer Composite
Ting-Chia Hsu, Li-Ting Lee, Xin-Yun Wu
February 12, 2020 (v1)
Subject: Materials
Keywords: biodegradable polymers, crystallization behavior, hexagonal boron nitride, poly(l-lactic acid), ternary composites
In this study, the novel ternary green polymer composites of poly(l-lactic acid) (PLLA)/poly(ethylene adipate)/hexagonal boron nitride (PLLA/PEA/h-BN) were synthesized and prepared. The crystallization rate of the biodegradable polymer PLLA in the composite was significantly increased with the addition of PEA and functional h-BN. In ternary PLLA/PEA/h-BN composites, PEA can be used as a plasticizer, while h-BN is a functional nucleation agent for PLLA. The analysis of the isothermal crystallization kinetics by the Avrami equation shows that the rate constant k of the ternary PLLA/PEA/h-BN composite represents the highest value, indicating the highest crystallization in the ternary composite. Adding h-BN in the composite can further increase the k value and increase the crystallization rate. Polarized optical microscopy (POM) images reveal that h-BN is an effective nucleation agent that increases the nucleation density of composites. Analysis of wide-angle X-ray diffraction (WAXD) furth... [more]
Exfoliation Behavior of Large Anionic Graphite Flakes in Liquid Produced by Salt-Assisted Ball Milling
Yoshihiko Arao, Jonathon D. Tanks, Kojiro Aida, Masatoshi Kubouchi
February 12, 2020 (v1)
Subject: Materials
Keywords: characterization, graphene, graphite structure, liquid-phase exfoliation
Functionalization of graphite is crucial for efficient and effective exfoliation to graphene. When negative charges are fixed to the edges of natural graphite, the resulting anionic graphite shows negative charging in a polar solvent. This enhanced negative charging is assumed to contribute the exfoliation of graphite during liquid-phase exfoliation (LPE). In this study, we prepared large anionic graphite flakes (~10 μm) by salt-assisted ball milling, as well as natural graphite flakes of the same size for comparison. During the LPE process, centrifugation speed and solvent type have dominant effects on graphene concentration and quality (e.g., size and thickness), so we investigated these factors for anionic graphite flakes in detail. The anionic graphite showed higher exfoliation efficiency in every type of solvent (isopropanol, methyl ethyl ketone, acetone, and water-based cosolvent) compared with the natural graphite. Monolayer graphene, with an average size of 80−200 nm, was obtai... [more]
Porous Aromatic Melamine Schiff Bases as Highly Efficient Media for Carbon Dioxide Storage
Raghad M. Omer, Emaad T. B. Al-Tikrity, Gamal A. El-Hiti, Mohammed F. Alotibi, Dina S. Ahmed, Emad Yousif
February 3, 2020 (v1)
Subject: Materials
Keywords: adsorption capacity, carbon dioxide storage, Energy, melamine Schiff bases, porosity properties, surface area
High energy demand has led to excessive fuel consumption and high-concentration CO2 production. CO2 release causes serious environmental problems such as the rise in the Earth’s temperature, leading to global warming. Thus, chemical industries are under severe pressure to provide a solution to the problems associated with fuel consumption and to reduce CO2 emission at the source. To this effect, herein, four highly porous aromatic Schiff bases derived from melamine were investigated as potential media for CO2 capture. Since these Schiff bases are highly aromatic, porous, and have a high content of heteroatoms (nitrogen and oxygen), they can serve as CO2 storage media. The surface morphology of the Schiff bases was investigated through field emission scanning electron microscopy, and their physical properties were determined by gas adsorption experiments. The Schiff bases had a pore volume of 0.005−0.036 cm3/g, an average pore diameter of 1.69−3.363 nm, and a small Brunauer−Emmett−Telle... [more]
Cross-Linking of Fibrex Gel by Fungal Laccase: Gel Rheological and Structural Characteristics
Sanaz Khalighi, Ralf G. Berger, Franziska Ersoy
February 3, 2020 (v1)
Subject: Materials
Keywords: cross-linking, fibrex gel, laccase, rheology, viscoelastic properties
Sugar beet fibre (fibrex) is an abundant side-stream from the sugar refining industry. A self-produced laccase from Funalia trogii (LccFtr) (0.05 U/µg FA) successfully cross-linked fibrex to an edible gel. Dynamic oscillation measurements of the 10% fibrex gels showed a storage modulus of 5.52 kPa and loss factors ≤ 0.36 in the range from 20 to 80 Hz. Comparing storage stability of sweetened 10% fibrex gels with sweetened commercial 6% gelatin gels (10% and 30% d-sucrose) indicated a constant storage modulus and loss factors ≤ 0.7 during four weeks of storage in fibrex gels. Loss factors of sweetened gelatin gels were ≤0.2, and their storage modulus decreased from 9 to 7 kPa after adding d-sucrose and remained steady for four weeks of storage. Fibrex gel characteristics, including high water holding capacity, swelling ratio in saliva, and heat resistance are attributed to a covalently cross-linked network. Vanillin, as a mediator, and citrus pectin did not enhance covalent cross-links... [more]
Entropy Generation and Dual Solutions in Mixed Convection Stagnation Point Flow of Micropolar Ti6Al4V Nanoparticle along a Riga Surface
A. Zaib, Umair Khan, Ilyas Khan, Asiful H. Seikh, El-Sayed M. Sherif
February 3, 2020 (v1)
Subject: Materials
Keywords: dual solution, entropy generation, micropolar fluid, Riga plate, thermal radiation, titanium alloy nanomaterial
Entropy generation and dual solutions are rarely studied in the literature. An analysis is attempted here. More exactly, the present paper looks at the impact of radiation of a micropolar fluid on mixed convective flow containing the titanium alloy Ti6Al4V nanoparticle along with a Riga plate. The study of dual-nature solution for the entropy generation along a Riga surface was not being explored in the literature; therefore, the current model focuses on the dual solutions of this complex nature model. Riga surface is identified as an actuator of electromagnetic in which electrodes are accumulated alternatively. This array produces the behavior of electromagnetic hydrodynamic in the flow field. The transmuted leading equations were worked out through the formula of 3-stage Lobatto IIIA. Influences of exercising enormous parameters on temperature distribution, velocity, and micro rotation fields are portrayed and argued. More than one solution is achieved in opposing flow, while in the... [more]
Iron Oxide/Chitosan Magnetic Nanocomposite Immobilized Manganese Peroxidase for Decolorization of Textile Wastewater
Saifeldin M. Siddeeg, Mohamed A. Tahoon, Wissem Mnif, Faouzi Ben Rebah
February 2, 2020 (v1)
Subject: Materials
Keywords: bioremediation, chitosan, enzymes, microorganisms, nanocomposites
Because of its effectiveness in organic pollutant degradation, manganese peroxidase (MnP) enzyme has attracted significant attention in recent years regarding its use for wastewater treatment. Herein, MnP was extracted from Anthracophyllum discolor fungi and immobilized on the surface of magnetic nanocomposite Fe3O4/chitosan. The prepared nanocomposite offered a high surface area for MnP immobilization. The influence of several environmental factors like temperature, pH, as well as storage duration on the activity of the extracted enzyme has been studied. Fourier transmission infrared spectroscopy (FT-IR), scanning electron microscope (SEM), X-ray diffraction (XRD), and transmission electron microscope (TEM) techniques were used for the characterization of the prepared MnP/Fe3O4/chitosan nanocomposite. The efficiencies of the prepared MnP/Fe3O4/chitosan nanocomposite for the elimination of reactive orange 16 (RO 16) and methylene blue (MB) industrial dyes were determined. According to... [more]
The Copper(II) Ions Solvent Extraction with a New Compound: 2,6-Bis(4-Methoxybenzoyl)-Diaminopyridine
Daria Bożejewicz, Katarzyna Witt, Małgorzata A. Kaczorowska, Borys Ośmiałowski
January 19, 2020 (v1)
Subject: Materials
Keywords: 2,6-bis(4-methoxybenzoyl)-diaminopyridine, dissociation constant, mass spectrometry, solvent extraction, stability constant
A new compound 2,6-bis(4-methoxybenzoyl)-diaminopyridine (L) was used as an extractant for copper(II) ion recovery in a solvent extraction conducted at a temperature of 25 °C. The best results (99% recovery of copper(II) ions) were obtained when the aqueous phase contained 0.001 mol/dm3 Cu(II) and 0.2 mol/dm3 NH3 (pH~5.8), while the organic phase was a 0.001 mol/dm3 chloroform solution of 2,6-bis(4-methoxybenzoyl)-diaminopyridine. Spectrophotometry studies were used to determine the dissociation constant of the tested compound and determine the stability constant of the complex of subjected compound with copper(II) ions. The high-resolution mass spectrometry (HRMS) and higher energy collisional dissociation tandem mass spectrometry (HCD MS/MS) methods have been applied for the confirmation of the structure of 2,6-bis(4-methoxybenzoyl)-diaminopyridine and to determine its complexation with Cu(II) in solution.
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