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Showing records 1 to 25 of 342. [First] Page: 1 2 3 4 5 Last
Effects of Particle Size on Diffusion Kinetics in Chinese Anthracites during CH4 Desorption
Jie Zang, Kai Wang, Yanbin Yu
July 2, 2020 (v1)
Subject: Materials
Keywords: Chinese anthracite, desorption, diffusion kinetics, particle size
Diffusion kinetics is widely acknowledged to dominate gas flow in coal matrix blocks. Knowledge of this topic is important for ongoing coalbed methane recovery and CO2-enhanced coalbed methane production. Because laboratory diffusivity measurements are normally conducted on powdered coals, it is unclear how representative the results are for coalbeds. Investigations into the effects of particle size on gas diffusivity can provide insights into the in situ diffusivity of the coal matrix. This paper presents measured CH4 desorption data in two Chinese anthracites (one brittle, one hard) having different particle sizes, to investigate the effects of particle size on diffusion kinetics. The experimental data were fitted by both the unipore (UP) and bidisperse (BD) models. The BD model agreed better with the measured data than the UP model, especially for the brittle coal. This indicated that the brittle coal was more abundant in macropores than the hard coal. Diffusivity in the hard coal d... [more]
Fabrication of Ultrathin MoS2 Nanosheets and Application on Adsorption of Organic Pollutants and Heavy Metals
Siyi Huang, Ziyun You, Yanting Jiang, Fuxiang Zhang, Kaiyang Liu, Yifan Liu, Xiaochen Chen, Yuancai Lv
July 2, 2020 (v1)
Subject: Materials
Keywords: Adsorption, liquid exfoliation, quenching, transition metal dichalcogenides
Owing to their peculiar structural characteristics and potential applications in various fields, the ultrathin MoS2 nanosheets, a typical two-dimensional material, have attracted numerous attentions. In this paper, a hybrid strategy with combination of quenching process and liquid-based exfoliation was employed to fabricate the ultrathin MoS2 nanosheets (MoS2 NS). The obtained MoS2 NS still maintained hexagonal phase (2H-MoS2) and exhibited evident thin layer-structure (1−2 layers) with inconspicuous wrinkle. Besides, the MoS2 NS dispersion showed excellent stability (over 60 days) and high concentration (0.65 ± 0.04 mg mL−1). The MoS2 NS dispersion also displayed evident optical properties, with two characteristic peaks at 615 and 670 nm, and could be quantitatively analyzed with the absorbance at 615 nm in the range of 0.01−0.5 mg mL−1. The adsorption experiments showed that the as-prepared MoS2 NS also exhibited remarkable adsorption performance on the dyes (344.8 and 123.5 mg g−1 o... [more]
Surface Modification of Bombyx mori Silk Fibroin Film via Thiol-ene Click Chemistry
Xiaoning Zhang, Jianwei Liang, Zhenyu Chen, Carrie Donley, Xiaolin Zhang, Guotao Cheng
July 2, 2020 (v1)
Subject: Materials
Keywords: Bombyx mori, silk fibroin film, surface modification, thiol-ene click chemistry
The purpose of this work is to develop a strategy for the surface modification of Bombyx mori silk fibroin (SF) film, via a thiol-ene click reaction, in order to expand its potential applicability. To achieve this goal, terminal thiol groups, from reduced glutathione, were introduced onto the surface of the SF film via a carbodiimide coupling reaction. These immobilized thiol groups act as robust crosslinkers and allow us to rapidly functionalize the surface with alkene group-containing molecules via ultraviolet (UV) light-initiated thiol-ene click chemistry. The X-ray photoelectron spectroscopy results specifically determined that alkene group-containing molecules and UV illumination are required for the thiol-ene click modification to take place on thiolated SF films. Fourier-transform infrared spectroscopy characterization of SF films indicated that the β-sheet conformation of SF was hampered throughout the modification process. Furthermore, it was found that the processes for thiol... [more]
Electrical Tree Initiation and Growth in Silicone Rubber under Combined DC-Pulse Voltage
Tao Han, Boxue Du, Jingang Su
June 23, 2020 (v1)
Subject: Materials
Keywords: combined DC-pulse voltage, electrical tree, inception voltage, prestress, silicone rubber, tree structure
Electrical tree is a serious threat to silicone rubber (SIR) insulation and can even cause breakdown. Electrical trees under alternating current (AC) and direct current (DC) voltage have been widely researched. While there are pulses in high-voltage direct current (HVDC) cables under operating conditions caused by lightning and operating overvoltage in the power system, little research has been reported about trees under combined DC-pulse voltage. Their inception and growth mechanism is still not clear. In this paper, electrical trees are studied under several types of combined DC-pulse voltage. The initiation and growth process was recorded by a digital microscope system. The experimental results indicate that the inception pulse voltage is different under each voltage type and is influenced by the combined DC. The initial tree has two structures, determined by the pulse polarity. With increased DC prestressing time, tree inception pulse voltage with the same polarity is clearly decre... [more]
Mesoporous Mn-Doped Fe Nanoparticle-Modified Reduced Graphene Oxide for Ethyl Violet Elimination: Modeling and Optimization Using Artificial Intelligence
Yu Hou, Jimei Qi, Jiwei Hu, Yiqiu Xiang, Ling Xin, Xionghui Wei
June 23, 2020 (v1)
Subject: Materials
Keywords: Artificial Intelligence, ethyl violet, gradient boosted regression trees, mesoporous materials, Mn-doped Fe/rGO nanocomposites
Mesoporous Mn-doped Fe nanoparticle-modified reduced graphene oxide (Mn-doped Fe/rGO) was prepared through a one-step co-precipitation method, which was then used to eliminate ethyl violet (EV) in wastewater. The prepared Mn-doped Fe/rGO was characterized by X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy, high-resolution transmission electron microscopy, scanning electron microscopy, energy dispersive spectroscopy, N2-sorption, small angle X-ray diffraction and superconducting quantum interference device. The Brunauer−Emmett−Teller specific surface area of Mn-doped Fe/rGO composites was 104.088 m2/g. The EV elimination by Mn-doped Fe/rGO was modeled and optimized by artificial intelligence (AI) models (i.e., radial basis function network, random forest, artificial neural network genetic algorithm (ANN-GA) and particle swarm optimization). Among these AI models, ANN-GA is considered as the best model for predicting the removal efficiency of EV by Mn-doped Fe/rGO... [more]
A Novel Porous Ni, Ce-Doped PbO2 Electrode for Efficient Treatment of Chloride Ion in Wastewater
Sheng Liu, Lin Gui, Ruichao Peng, Ping Yu
June 23, 2020 (v1)
Subject: Materials
Keywords: active surface area, co-doping, porous Ni-Ce-PbO2, removal rate
The porous Ti/Sb-SnO2/Ni-Ce-PbO2 electrode was prepared by using a porous Ti plate as a substrate, an Sb-doped SnO2 as an intermediate, and a PbO2 doped with Ni and Ce as an active layer. The surface morphology and crystal structure of the electrode were characterized by scanning electron microscope(SEM), energy dispersive spectrometer(EDS), and X-Ray diffraction(XRD). The electrochemical performance of the electrodes was tested by linear sweep voltammetry (LSV), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and electrode life test. The results show that the novel porous Ni-Ce-PbO2 electrodes with larger active surface area have better electrochemical activity and longer electrode life than porous undoped PbO2 electrodes and flat Ni-Ce-PbO2 electrodes. In this work, the removal of Cl− in simulated wastewater on three electrodes was also studied. The results show that the removal effect of the porous Ni-Ce-PbO2 electrode is obviously better than the other two el... [more]
Rheological Properties of Aqueous Dispersions of Bacterial Cellulose
Markel I. Vinogradov, Igor S. Makarov, Lyudmila K. Golova, Peter S. Gromovykh, Valery G. Kulichikhin
June 10, 2020 (v1)
Subject: Materials
Keywords: bacterial cellulose, gel, rheology, thickener, thixotropy, water dispersion
Bacterial cellulose as polysaccharide possessing outstanding chemical purity and a unique structure compared with wood cellulose, attracts great attention as a hydrocolloid system. It was shown, that at intense mechanical action on a neat bacterial cellulose film in presence of water, the gel-like dispersions are obtained. They retain stability in time (at least, up to several months) and temperature (at least, up to 60 °C) without macro-phase separation on aqueous and cellulose phases. The main indicator of the stability is constant viscosity values in time, as well as fulfilling the Arrhenius dependence for temperature dependence of viscosity. Flow curves of diluted dispersions (BC content less than 1.23%) show strong non-Newtonian behavior over the entire range of shear rates. It is similar with dispersions of micro- and nanocrystalline cellulose, but the absolute viscosity value is much higher in the case of BC due to more long fibrils forming more dense entanglements network than... [more]
Early Stage of Corrosion Formation on Pipeline Steel X70 Under Oxyfuel Atmosphere at Low Temperature
Andreas Kratzig, Le Quynh Hoa, Dirk Bettge, Martina Menneken, Ralph Bäßler
June 10, 2020 (v1)
Subject: Materials
Keywords: carbon steel, CCUS, CO2 pipeline transport, corrosion, impurities, in-situ ED-XRD, Oxyfuel
The early stage of corrosion formation on X70 pipeline steel under oxyfuel atmosphere was investigated by applying a simulated gas mixture (CO2 containing 6700 ppmv O2, 100 ppmv NO2, 70 ppmv SO2 and 50 ppmv H2O) for 15 h at 278 K and ambient pressure. Short-term tests (6 h) revealed that the corrosion starts as local spots related to grinding marks progressing by time and moisture until a closed layer was formed. Acid droplets (pH 1.5), generated in the gas atmosphere, containing a mixture of H2SO4 and HNO3, were identified as corrosion starters. After 15 h of exposure, corrosion products were mainly X-ray amorphous and only partially crystalline. In-situ energy-dispersive X-ray diffraction (EDXRD) results showed that the crystalline fractions consist primarily of water-bearing iron sulfates. Applying Raman spectroscopy, water-bearing iron nitrates were detected as subordinated phases. Supplementary long-term tests exhibited a significant increase in the crystalline fraction and format... [more]
Simultaneous Adsorption of 4,6-Dimethyldibenzothiophene and Quinoline over Nickel and Boron Modified Gamma-Al2O3 Adsorbent
Esteban Camu, Barbara Pasten, Camila Matus, Fernanda Ramirez, Juan Ojeda, Gonzalo Aguila, Patricio Baeza
June 10, 2020 (v1)
Subject: Materials
Keywords: 4,6-dimethyldibenzothiophene, Adsorption, alumina, boron, nickel, quinoline
The simultaneous adsorption of quinoline and 4,6-dimethyldibenzothiophene over adsorbents, based on alumina modified with boron and nickel under ambient temperature and pressure, was studied. The adsorbents were characterized by BET specific surface area, a potentiometric method for the determination of acid strength, electrophoretic migration, and X-ray diffraction. The results showed that the adsorbent containing nickel had better adsorption capacity than the adsorbent modified with nickel and boron, which was attributed to its greater acidity and ability to generate π-complexation between the adsorbent and the molecules. In terms of selectivity, quinoline was more adsorbed than 4,6-dimethyldibenzothiophene in all systems, due to the basic nature of quinoline. The experimental data in all cases were adjusted by three kinetic models (Yoon−Nelson, Yan and Thomas), and the regression coefficients in all models were close to one. Finally, the values of the kinetic constant obtained by th... [more]
Preparation and Characterization of Environmentally Friendly Controlled Release Fertilizers Coated by Leftovers-Based Polymer
Cong Jia, Panfang Lu, Min Zhang
June 10, 2020 (v1)
Subject: Materials
Keywords: bio-based polyurethane, controlled release fertilizers, environment-friendly, leftovers
In this work, a novel bio-based polyurethane (PU) was synthesized by using a leftovers (SF)-based polyol and isocyanate for controlled release fertilizers (CRFs). Its chemical structure, surface elemental compositions and distribution were examined by Fourier transform infrared (FTIR), energy dispersive spectroscopy (EDX) and a multifunctional imaging electron spectrometer (XPS). The microstructure morphology of CRFs were examined by SEM. The nutrient release behaviors of CRFs were observed in water. The results demonstrated that SF-based PU-coated urea (FPU) had a denser structure and better nutrient releasing ability. Findings from this work indicated that the use of SF as a coating material of environment-friendly CRFs had great potential, and would hopefully be used for horticultural and agricultural applications.
Investigation of Heating and Freezing Pretreatments on Mechanical, Chemical and Spectral Properties of Bulk Sunflower Seeds and Oil
Gürkan Alp Kağan Gürdil, Abraham Kabutey, Kemal Çağatay Selvi, Petr Hrabě, David Herák, Adéla Fraňková
June 10, 2020 (v1)
Subject: Materials
Keywords: energy demand, linear compression, oil expression efficiency, oil quality, oil-bearing crop
The present study examined the effects of heating and freezing pretreatments on the mechanical, chemical, and spectral characteristics of sunflower seeds and oil under a linear compression process involving a universal compression-testing machine and a pressing vessel of diameter 60 mm with a plunger. The heating temperatures ranged from 40 to 80 °C and freezing temperatures from −2 to −36 °C at constant heating time of 30 min. The pretreated samples of initial height of 80 mm (22.6 × 10−5 m3) were compressed under a preset load of 100 kN and a speed of 5 mm/min. The results showed that oil expression efficiency significantly increased (p < 0.05) with increased heating temperatures but decreased with freezing temperatures. The lowest energy per volume oil of 22.55 ± 0.919 kJ/L was recorded at 80 °C compared to 26.40 ± 0.307 kJ/L noticed at −2 °C and control (25 °C) of 33.93 ± 3.866 kJ/L. The linear regression equations expressing oil expression efficiency, energy per volume oil, per... [more]
NMR Determination of Free Fatty Acids in Vegetable Oils
Maria Enrica Di Pietro, Alberto Mannu, Andrea Mele
June 10, 2020 (v1)
Subject: Materials
Keywords: acid value, free fatty acids, NMR quantification, nuclear magnetic resonance, waste cooking oils, waste oil characterization
The identification and quantification of free fatty acids (FFA) in edible and non-edible vegetable oils, including waste cooking oils, is a crucial index to assess their quality and drives their use in different application fields. NMR spectroscopy represents an alternative tool to conventional methods for the determination of FFA content, providing us with interesting advantages. Here the approaches reported in the literature based on 1H, 13C and 31P NMR are illustrated and compared, highlighting the pros and cons of the suggested strategies.
Evaluation of Calcium Oxide Nanoparticles from Industrial Waste on the Performance of Hardened Cement Pastes: Physicochemical Study
Youssef Abdelatif, Abdel-Aal M. Gaber, Abd El-Aziz S. Fouda, Tarek Alsoukarry
June 10, 2020 (v1)
Subject: Materials
Keywords: blended cement paste, bulk density, calcination, calcium oxide nanoparticles, compressive strength, mix design
Large amounts of carbonated mud waste (CMW) require disposal during sugar manufacturing after the carbonation process. The lightweight of CMW enables its utilization as a partial replacement for the cement to reduce costs and CO2 emissions. Here, various levels of CMW, namely, 0, 5, 10, 15, 20, and 25 wt.% were applied to produce composite cement samples with ordinary Portland cement (OPC) as a regular mix design series. Pure calcium oxide (CaO) nanoparticles were obtained after the calcination of CMW. The techniques of X-ray fluorescence spectrometers (XRF), Transmission electron microscope (TEM), Selected area diffraction (SAED), Scanning electron microscope (SEM), energy dixpersive X-ray (EDX), and dynamic light scattering (DLS) were used to characterize the obtained CaO nanoparticles. According to the compressive strength and bulk density results, 15 wt.% CMW was optimal for the mix design. The specific surface area increased from 27.8 to 134.8 m2/g when the CMW was calcined to 600... [more]
A Simple Approach for Determining the Maximum Sorption Capacity of Chlorpropham from Aqueous Solution onto Granular Activated Charcoal
Bandar R. M. Alsehli
June 10, 2020 (v1)
Subject: Materials
Keywords: chlorpropham, isotherm models, UV/VIS
UV-Vis spectrophotometer was used to determine chlorpropham (CIPC) concentration in aqueous solution. The method was validated in term of linearity, precision and limit of detection and limit of quantitation. The correlation coefficient of standards calibration curve of (1.0−10.0 µg/mL CIPC) was R2 = 1 with a precision (RSD%, n=10) ranged from (0.87−0.53%). The limit of detection (LOD) and limit of quantitation (LOQ) based on the regression statistics of the calibration curve data of (1.0−10.0 µg/mL CIPC) were 0.04 µg/mL and 0.11 µg/mL respectively. The activated carbon adsorbent was found to be effective for the removal approximately 80% of CIPC from aqueous solution. Several isotherm models (Langmuir, Freundlich, Tempkin and Dubinin−Radushkevich) were evaluated. The maximum monolayer sorption capacity (Qm) from the Langmuir isotherm model was determined to be (44316.92 µg/g). The separation factor (RL) is 0.11 which indicates a favorable equilibrium sorption with the R2 value of 0.99... [more]
Methane Adsorption Interpreting with Adsorption Potential and Its Controlling Factors in Various Rank Coals
Feng Qiu, Dameng Liu, Yidong Cai, Ning Liu, Yongkai Qiu
June 3, 2020 (v1)
Subject: Materials
Keywords: adsorption potential, coalbed methane, controlling factors, Langmuir adsorption curve, pore structure
Water content, metamorphism (coal rank) particle size, and especially pore structure, strongly influence the adsorption capacity of coal to methane. To understand the mechanism of methane adsorption in different rank coals, and its controlling factors, isothermal adsorption experiments with different coal ranks, moisture contents and particle sizes at the temperature of 303.15 K were conducted. In addition, the pore structures of coals were investigated through N2 adsorption/desorption experiments at the low-temperature of 77 K for selected coals from the Junggar Basin of NW China, Qinshui Basin and Ordos Basin of north China. Moreover, the adsorption potential of methane on the surface of the coal matrix was calculated, the controlling factors of which were discussed. The obtained methane isothermal adsorption result shows that the Langmuir volume (VL) of coal is independent of the particle size, and decreases with the increase of moisture content, which decreases first and then incre... [more]
Low-Molecular-Weight Phenols Recovery by Eco-Friendly Extraction from Quercus Spp. Wastes: An Analytical and Biomass-Sustainability Evaluation
Federica Ianni, Enrico Segoloni, Francesca Blasi, Francesco Di Maria
June 3, 2020 (v1)
Subject: Materials
Keywords: circular economy, lignin, mild extraction/hydrolysis protocols, phenolic compounds recovery, wood waste
In this work, chemical−physical protocols aimed at the implementation of eco-friendly and biomass-sustainable recovery processes of useful compounds from forestry and/or wood industry wastes were evaluated. Four species of interest in industrial and environmental fields (Quercus cerris, Quercus ilex, and Robinia pseudoacacia from Central Italy, Quercus petraea from France) were submitted to neutral extraction and analyzed by gaschromatography, with mass spectrometry identification of low-molecular-weight phenols. Moreover, Quercus petraea heartwood samples were submitted to three extraction/hydrolysis protocols in an alkaline environment, and the byproducts from the lignin degradation were identified and evaluated. The recovery of bioactive phenols from forestry wastes by applying eco-friendly extractive protocols may reveal a precious strategy for rethinking the management of such wastes, in line with the fundamentals of “circular economy”.
Adsorption and Separation of the H2O/H2SO4 and H2O/C2H5OH Mixtures: A Simulated and Experimental Study
Jesse Y. Rumbo Morales, Alan F. Perez Vidal, Gerardo Ortiz Torres, Alexis U. Salas Villalobo, Felipe de J. Sorcia Vázquez, Jorge A. Brizuela Mendoza, Miguel De-la-Torre, Jorge S. Valdez Martínez
May 22, 2020 (v1)
Subject: Materials
Keywords: heat and chemical treatment, natural and synthetic zeolites, pressure swing adsorption process
Adsorption processes are characterized by their kinetics and equilibrium isotherms described by mathematical models. Nowadays, adsorption with molecular sieves is a method used to separate certain elements or molecules from a mixture and produce hydrogen, nitrogen, oxygen, ethanol, or water treatment. This study had two main objectives. The first one was focused on the use of different natural (Clinoptilolite-S.L. Potosi, Clinoptilolite-Puebla, and Heulandite-Sonora) and synthetic (Zeolite Type 3A) adsorbents to separate the mixtures H 2 O / H 2 S O 4 and H 2 O / C 2 H 5 O H . It was determined that both Zeolite Type-3A and Heulandite-Sonora have greater adsorption capacity in a shorter time compared with the Clinoptilolites at different temperatures. The second objective was the simulation of a pressure swing adsorption process to dehydrate ethanol using the parameters obtained from Zeolite Type 3A (with maximum adsorption capacity). Several configurations w... [more]
Metal−Organic Framework Thin Films: Fabrication, Modification, and Patterning
Yujing Zhang, Chih-Hung Chang
May 22, 2020 (v1)
Subject: Materials
Keywords: fabrication, metal–organic framework, patterning, thin film
Metal−organic frameworks (MOFs) have been of great interest for their outstanding properties, such as large surface area, low density, tunable pore size and functionality, excellent structural flexibility, and good chemical stability. A significant advancement in the preparation of MOF thin films according to the needs of a variety of applications has been achieved in the past decades. Yet there is still high demand in advancing the understanding of the processes to realize more scalable, controllable, and greener synthesis. This review provides a summary of the current progress on the manufacturing of MOF thin films, including the various thin-film deposition processes, the approaches to modify the MOF structure and pore functionality, and the means to prepare patterned MOF thin films. The suitability of different synthesis techniques under various processing environments is analyzed. Finally, we discuss opportunities for future development in the manufacturing of MOF thin films.
Eucalyptus Kraft Lignin as an Additive Strongly Enhances the Mechanical Resistance of Tree-Leaf Pellets
Leonardo Clavijo, Slobodan Zlatanovic, Gerd Braun, Michael Bongards, Andrés Dieste, Stéphan Barbe
May 22, 2020 (v1)
Subject: Materials
Keywords: additive, biofuel, circular economy, eucalyptus kraft lignin, pellet, tree leaf
Pelleted biomass has a low, uniform moisture content and can be handled and stored cheaply and safely. Pellets can be made of industrial waste, food waste, agricultural residues, energy crops, and virgin lumber. Despite their many desirable attributes, they cannot compete with fossil fuel sources because the process of densifying the biomass and the price of the raw materials make pellet production costly. Leaves collected from street sweeping are generally discarded in landfills, but they can potentially be valorized as a biofuel if they are pelleted. However, the lignin content in leaves is not high enough to ensure the physical stability of the pellets, so they break easily during storage and transportation. In this study, the use of eucalyptus kraft lignin as an additive in tree-leaf pellet production was studied. Results showed that when 2% lignin is added the abrasion resistance can be increased to an acceptable value. Pellets with added lignin fulfilled all requirements of Europ... [more]
Preparation of Nano-Porous Carbon-Silica Composites and Its Adsorption Capacity to Volatile Organic Compounds
Lipei Fu, Jiahui Zhu, Weiqiu Huang, Jie Fang, Xianhang Sun, Xinya Wang, Kaili Liao
May 22, 2020 (v1)
Subject: Materials
Keywords: Adsorption, carbon-silica composites, dynamic adsorption, regenerating property, volatile organic compounds (VOCs)
Carbon-silica composites with nanoporous structures were synthesized for the adsorption of volatile organic compounds (VOCs), taking tetraethyl orthosilicate (TEOS) as the silicon source and activated carbon powder as the carbon source. The preparation conditions were as follows: the pH of the reaction system was 5.5, the hydrophobic modification time was 50 h, and the dosage of activated carbon was 2 wt%. Infrared spectrum analysis showed that the activated carbon was dispersed in the pores of aerogel to form the carbon-silica composites material. The static adsorption experiments, dynamic adsorption-desorption experiments, and regeneration experiments show that the prepared carbon-silica composites have microporous and mesoporous structures, the adsorption capacity for n-hexane is better than that of conventional hydrophobic silica gel, and the desorption performance is better than that of activated carbon. It still has a high retention rate of adsorption capacity after multiple adso... [more]
Available Technologies and Materials for Waste Cooking Oil Recycling
Alberto Mannu, Sebastiano Garroni, Jesus Ibanez Porras, Andrea Mele
May 22, 2020 (v1)
Subject: Materials
Keywords: biodiesel, biolubricant, recycling, vegetable oil degumming, vegetable oil filtration, waste cooking oil
Recently, the interest in converting waste cooking oils (WCOs) to raw materials has grown exponentially. The driving force of such a trend is mainly represented by the increasing number of WCO applications, combined with the definition, in many countries, of new regulations on waste management. From an industrial perspective, the simple chemical composition of WCOs make them suitable as valuable chemical building blocks, in fuel, materials, and lubricant productions. The sustainability of such applications is sprightly related to proper recycling procedures. In this context, the development of new recycling processes, as well as the optimization of the existing ones, represents a priority for applied chemistry, chemical engineering, and material science. With the aim of providing useful updates to the scientific community involved in vegetable oil processing, the current available technologies for WCO recycling are herein reported, described, and discussed. In detail, two main types of... [more]
Evaluation of Polymeric Materials for Chemical Enhanced Oil Recovery
Alison J. Scott, Laura Romero-Zerón, Alexander Penlidis
May 22, 2020 (v1)
Subject: Materials
Keywords: enhanced oil recovery (EOR), partially hydrolyzed polyacrylamide (HPAM), polyacrylamide, polymer flooding, xanthan gum
Polymer flooding is a promising enhanced oil recovery (EOR) technique; sweeping a reservoir with a dilute polymer solution can significantly improve the overall oil recovery. In this overview, polymeric materials for enhanced oil recovery are described in general terms, with specific emphasis on desirable characteristics for the application. Application-specific properties should be considered when selecting or developing polymers for enhanced oil recovery and should be carefully evaluated. Characterization techniques should be informed by current best practices; several are described herein. Evaluation of fundamental polymer properties (including polymer composition, microstructure, and molecular weight averages); resistance to shear/thermal/chemical degradation; and salinity/hardness compatibility are discussed. Finally, evaluation techniques to establish the polymer flooding performance of candidate EOR materials are described.
Current Use of Carbon-Based Materials for Biomedical Applications—A Prospective and Review
Govindasamy Rajakumar, Xiu-Hua Zhang, Thandapani Gomathi, Sheng-Fu Wang, Mohammad Azam Ansari, Govindarasu Mydhili, Gnanasundaram Nirmala, Mohammad A. Alzohairy, Ill-Min Chung
May 22, 2020 (v1)
Subject: Materials
Keywords: biomedical applications, Carbon NanoTube (CNT), carbon-based nanomaterials, Graphene (G), Graphene Oxides (GO), reduced Graphene (rGO)
Among a large number of current biomedical applications in the use of medical devices, carbon-based nanomaterials such as graphene (G), graphene oxides (GO), reduced graphene oxide (rGO), and carbon nanotube (CNT) are frontline materials that are suitable for developing medical devices. Carbon Based Nanomaterials (CBNs) are becoming promising materials due to the existence of both inorganic semiconducting properties and organic π-π stacking characteristics. Hence, it could effectively simultaneously interact with biomolecules and response to the light. By taking advantage of such aspects in a single entity, CBNs could be used for developing biomedical applications in the future. The recent studies in developing carbon-based nanomaterials and its applications in targeting drug delivery, cancer therapy, and biosensors. The development of conjugated and modified carbon-based nanomaterials contributes to positive outcomes in various therapies and achieved emerging challenges in preclinical... [more]
Facile Synthesis of Bio-Template Tubular MCo2O4 (M = Cr, Mn, Ni) Microstructure and Its Electrochemical Performance in Aqueous Electrolyte
Deepa Guragain, Camila Zequine, Ram K Gupta, Sanjay R Mishra
May 22, 2020 (v1)
Subject: Materials
Keywords: bio-template, cyclic voltammetry, electrochemical, MCo2O4 (M = Cr, Mn, Ni), specific capacitance
In this project, we present a comparative study of the electrochemical performance for tubular MCo2O4 (M = Cr, Mn, Ni) microstructures prepared using cotton fiber as a bio-template. Crystal structure, surface properties, morphology, and electrochemical properties of MCo2O4 are characterized using X-ray diffraction (XRD), gas adsorption, scanning electron microscopy (SEM), Fourier transforms infrared spectroscopy (FTIR), cyclic voltammetry (CV), and galvanostatic charge-discharge cycling (GCD). The electrochemical performance of the electrode made up of tubular MCo2O4 structures was evaluated in aqueous 3M KOH electrolytes. The as-obtained templated MCo2O4 microstructures inherit the tubular morphology. The large-surface-area of tubular microstructures leads to a noticeable pseudocapacitive property with the excellent electrochemical performance of NiCo2O4 with specific capacitance value exceeding 407.2 F/g at 2 mV/s scan rate. In addition, a Coulombic efficiency ~100%, and excellent cy... [more]
New Hybrid Bioactive Composites for Bone Substitution
Anna Ślósarczyk, Joanna Czechowska, Ewelina Cichoń, Aneta Zima
May 22, 2020 (v1)
Subject: Materials
Keywords: chitosan, hybrid materials, hydroxyapatite
Recently, intensive efforts have been undertaken to find new, superior biomaterial solutions in the field of hybrid inorganic−organic materials. In our studies, biomicroconcretes containing hydroxyapatite (HAp)−chitosan (CTS) granules dispersed in an α tricalcium phospahate (αTCP) matrix were investigated. The influence of CTS content and the size of granules on the physicochemical properties of final bone implant materials (setting time, porosity, mechanical strength, and phase composition) were evaluated. The obtained materials were found to be promising bone substitutes for use in non-load bearing applications.
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