Showing papers in "Industrial & Engineering Chemistry Research in 2014"
TL;DR: A survey of all the state-of-the-art formulations of thermophysical properties is presented, finding the most-accurate thermodynamic properties are obtained from multiparameter Helmholtz-energy-explicit-type formulations.
Abstract: Over the last few decades, researchers have developed a number of empirical and theoretical models for the correlation and prediction of the thermophysical properties of pure fluids and mixtures treated as pseudo-pure fluids In this paper, a survey of all the state-of-the-art formulations of thermophysical properties is presented The most-accurate thermodynamic properties are obtained from multiparameter Helmholtz-energy-explicit-type formulations For the transport properties, a wider range of methods has been employed, including the extended corresponding states method All of the thermophysical property correlations described here have been implemented into CoolProp, an open-source thermophysical property library This library is written in C++, with wrappers available for the majority of programming languages and platforms of technical interest As of publication, 110 pure and pseudo-pure fluids are included in the library, as well as properties of 40 incompressible fluids and humid air The source code for the CoolProp library is included as an electronic annex
1,472 citations
TL;DR: In this article, the thermal stability of 66 ionic liquids (ILs) was investigated using the thermogravimetric analysis (TGA) method, and the thermal decomposition kinetics of ILs were analyzed using pseudo-zero-order rate expression and their activation energy was obtained.
Abstract: The thermal stabilities of 66 ionic liquids (ILs) were investigated using the thermogravimetric analysis (TGA) method. Isothermal TGA studies on the ILs showed that ILs exhibit decomposition at temperatures lower than the onset decomposition temperature (Tonset), which is determined from ramped temperature TGA experiments. Thermal decomposition kinetics of ILs was analyzed using pseudo-zero-order rate expression and their activation energy was obtained. Parameter T0.01/10h, the temperature at which 1% mass loss occurs in 10 h, was used to evaluate the long-term thermal stability of ILs. The thermal stability of the ILs was classified to five levels according to Tonset. The ILs thermal stability is dependent on the structure of ILs, i.e., cation modification, cation and anion type. The correlations between the stability and the hydrophilicity of ILs were discussed. Finally, the thermal stabilities of acetate-based ILs, amino acid ILs, and dicyanamide ILs were analyzed.
556 citations
TL;DR: The use of conventional treatment methods along with membrane reactors and advanced posttreatment methods resulting in a hybrid wastewater treatment technology appear to be the best and will prove useful for treatment of wastewater from the pharmaceutical industry.
Abstract: Pharmaceutical compounds are typically produced in batch processes leading to the presence of a wide variety of products in wastewaters which are generated in different operations, wherein copious quantities of water are used for washing of solid cake, or extraction, or washing of equipment. The presence of pharmaceutical compounds in drinking water comes from two different sources: production processes of the pharmaceutical industry and common use of pharmaceutical compounds resulting in their presence in urban and farm wastewaters. The wastewaters generated in different processes in the manufacture of pharmaceuticals and drugs contain a wide variety of compounds. Further, reuse of water after removal of contaminants, whether pharmaceuticals or otherwise, is required by industry. In view of the scarcity of water resources, it is necessary to understand and develop methodologies for treatment of pharmaceutical wastewater as part of water management. In this review, the various sources of wastewaters in the pharmaceutical industry are identified and the best available technologies to remove them are critically evaluated. Effluent arising from different sectors of active pharmaceutical ingredients (API), bulk drugs, and related pharmaceutics, which use large quantities of water, is evaluated and strategies are proposed to recover to a large extent the valuable compounds, and finally the treatment of very dilute but detrimental wastewaters is discussed. No single technology can completely remove pharmaceuticals from wastewaters. The use of conventional treatment methods along with membrane reactors and advanced posttreatment methods resulting in a hybrid wastewater treatment technology appear to be the best. The recommendations provided in this analysis will prove useful for treatment of wastewater from the pharmaceutical industry.
554 citations
TL;DR: In this paper, a facile in situ precipitation method was used to obtain high photocatalytic activity for the decolorization of methyl orange (MO) under visible-light irradiation.
Abstract: Highly efficient visible-light-driven g-C3N4/Ag3PO4 hybrid photocatalysts with different weight ratios of g-C3N4 were prepared by a facile in situ precipitation method and characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectrometry and UV–vis diffuse reflectance spectroscopy. Under visible-light irradiation (>440 nm), g-C3N4/Ag3PO4 photocatalysts displayed the higher photocatalytic activity than pure g-C3N4 and Ag3PO4 for the decolorization of methyl orange (MO). Among the hybrid photocatalysts, g-C3N4/Ag3PO4 with 25 wt % of g-C3N4 exhibited the highest photocatalytic activity for the decolorization of MO. The complete decolorization of MO was achieved for only 5 min of visible-light irradiation. X-ray photoelectron spectroscopy results revealed that metallic Ag particles on the surface of g-C3N4/Ag3PO4 hybrid were formed during the catalysts preparation. In addition, the quenching effects of different scavengers displayed tha...
344 citations
TL;DR: In this article, an electron beam irradiation (30 kGy and 90 kGy) approach was used to narrow the band gap of the pristine CeO2 nanostructure (p-CeO2) to enhance their visible light activity through defect engineering.
Abstract: This work reports an electron beam irradiation (30 kGy and 90 kGy) approach to narrow the band gap of the pristine CeO2 nanostructure (p-CeO2) to enhance their visible light activity through defect engineering. This was confirmed by diffuse reflectance spectroscopy, photoluminescence, Raman spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy (XPS), Brunauer–Emmett–Teller, electrochemical impedance spectroscopy, and linear scan voltammetry. XPS revealed changes in the surface states, composition, Ce4+ to Ce3+ ratio, and other defects in the modified CeO2 nanostructures (m-CeO2). The m-CeO2 exhibits excellent photocatalytic activities by degrading 4-nitrophenol and methylene blue in the presence of visible light (λ > 400 nm) compared to the p-CeO2. The optical, photocatalytic, and photoelectrochemical studies and proposed mechanism further support the enhanced visible light photocatalytic activities of the m-CeO2. This study confirmed that defect-induced band gap engineered m-CeO2 could be use...
266 citations
TL;DR: In this article, a magnetic cellulose/graphene oxide composite (MCGO) was prepared as a novel adsorbent to dispose of dye wastewater, and the morphology and chemical structure of the MCGO composite were characterized by the Fourier transform infrared spectrometer (FT-IR), X-ray diffraction (XRD), and scanning electronic microscope (SEM).
Abstract: In the present study, magnetic cellulose/graphene oxide composite (MCGO) was prepared as a novel adsorbent to dispose of dye wastewater. The morphology and chemical structure of the MCGO composite were characterized by the Fourier transform infrared spectrometer (FT-IR), X-ray diffraction (XRD), and scanning electronic microscope (SEM). The adsorption of methylene blue (MB) onto MCGO was studied in relation to initial concentration of MB, contact time, adsorbent dose, and pH value of solution. Adsorption kinetics and the equilibrium adsorption isotherm were fitted by a pseudo-second-order kinetic model and Langmuir isotherm, respectively. The thermodynamic parameters indicated that the adsorption was spontaneous, favorable, and exothermic in nature. Furthermore, MCGO was very stable and can easily be recycled. The adsorption efficiency of MCGO was still over 89% after recycling for five times.
242 citations
TL;DR: In this article, a novel polyvinylidene fluoride (PVDF) mixed matrix ultrafiltration membrane containing reduced graphene oxide/titanium dioxide (rGO/TiO2) nanocomposite was prepared by phase inversion method.
Abstract: A novel polyvinylidene fluoride (PVDF) mixed matrix ultrafiltration membrane containing reduced graphene oxide/titanium dioxide (rGO/TiO2) nanocomposite was prepared by phase inversion method. The synthesized rGO/TiO2 was characterized by X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy (SEM) techniques. The prepared rGO/TiO2 blended PVDF membranes were characterized by atomic force microscopy, SEM, water contact angle, porosity, permeation measurements, and rejection tests. Due to the high hydrophilicity of the rGO/TiO2 nanocomposite, the rGO/TiO2/PVDF membranes were more hydrophilic and had higher pure water flux and flux recovery ratio than the bare PVDF. The blended membranes showed remarkably good properties and performance when the rGO/TiO2 content of 0.05 wt % was added to the casting solution. The pure water flux of the 0.05 wt % rGO/TiO2 blended membrane was increased by 54.9% compared with the bare PVDF membrane. The antifouling study of the membranes ...
227 citations
TL;DR: Ferrocene (Fc) was used to catalyze a heterogeneous Fenton reaction for the degradation of methylene blue (MB) as mentioned in this paper, and the high catalytic activity and stability of Fc in the Fc/Fenton-like system are confounded.
Abstract: Ferrocene (Fc) was used to catalyze a heterogeneous Fenton reaction for the degradation of methylene blue (MB). The high catalytic activity and stability of Fc in the Fc/Fenton-like system are conf...
225 citations
TL;DR: In this paper, the influence of the SiO2/Al2O3 ratio (30, 80, and 280) on HZSM-5 zeolite properties was reported.
Abstract: This article reports the influence of the SiO2/Al2O3 ratio (30, 80, and 280) on HZSM-5 zeolite properties. XRD patterns show a decrease in the XRD peak intensity at low 2θ angles for low SiO2/Al2O3 ratio zeolites. N2 adsorption and desorption isotherms display hysteresis with both micropores and mesopores likely contributing to the particles network. The NLDFT cylindrical model confirms the characteristic 5.5 A micropores in the zeolite pore framework. Furthermore, specific surface area, pore volume, and pore size distributions demonstrate that changes in the SiO2/Al2O3 ratio do not influence HZSM-5 structural properties. NH3-TPD shows both weak and strong acid sites. Pyridine-FTIR also confirms that, in HZSM-5, the weak acidity encompasses Lewis and hydrogen-bonded sites, while the strong acidity mainly involves the Bronsted acid sites. It is proven that the ratio of weak to strong acid sites as measured by NH3-TPD and Pyridine-FTIR displays similar changes to the SiO2/Al2O3 ratio. Furthermore, NH3 desor...
220 citations
TL;DR: In this paper, a simple reflux treatment of ZnFe2O4 nanoparticles (NPs) with graphitic C3N4 sheets in methanol at 90 °C was successfully synthesized through a simple refining treatment of NPs.
Abstract: Magnetic ZnFe2O4–C3N4 hybrids were successfully synthesized through a simple reflux treatment of ZnFe2O4 nanoparticles (NPs) (ca. 19.1 nm) with graphitic C3N4 sheets in methanol at 90 °C, and characterized by X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric and differential thermal analysis, X-ray photoelectron spectroscopy, high-resolution transmission electron microscopy, and UV–vis diffuse reflectance spectroscopy. Also, the catalytic activities of heterogeneous ZnFe2O4–C3N4 catalysts were evaluated in photo-Fenton discoloration toward Orange II using H2O2 as an oxidant under visible light (λ > 420 nm) irradiation. The reaction kinetics, degradation mechanism, and catalyst stability, as well as the roles of ZnFe2O4 and C3N4 in photoreaction, were comprehensively studied. It was found that the ZnFe2O4–C3N4 photocatalysts presented remarkable catalytic ability at neutral conditions, which is a great advantage over the traditional Fenton system (Fe2+/H2O2). The ZnFe2O4–C3N4 hy...
214 citations
TL;DR: In this article, current progress in the area of photocatalysis using energy efficient Light Emitting Diodes (LEDs) as an irradiation source is discussed, and future prospects and challenges for the application of LEDs for photocatalytic environmental pollutant degradation have been highlighted.
Abstract: In this review, current progress in the area of photocatalysis using energy efficient Light Emitting Diodes (LEDs) as an irradiation source is discussed. LEDs are small in size, robust, do not contain mercury, have a longer life span than conventional light sources, and can operate on a direct current. These properties of LEDs offer a new alternative to traditional ultraviolet sources and open new possibilities for photocatalytic degradation with reduced power consumption, along with greater freedom in the design of various types of photocatalytic reactors. The present review mainly focuses on the photocatalytic degradation of organic compounds and dyes as well as the sterilization of microrganisms which are present in water and air, using irradiation by various types of LEDs, photocatalytic reactors, and catalysts. In addition, future prospects and challenges for the application of LEDs for to photocatalytic environmental pollutant degradation have been highlighted.
TL;DR: In this paper, a review of recent developments in the chemical recycling (glycolysis and aminolysis) of poly(ethylene terephthalate) (PET) products is presented.
Abstract: Global production and consumption of poly(ethylene terephthalate) (PET) products has increased dramatically over the past few decades. World consumption of PET has exceeded 13 million tonnes, of which about 1.5 million tonnes is exclusively consumed by the packaging sector itself. However, this tremendous increase in PET consumption has resulted in the accumulation of an enormous quantity of waste, the disposal of which is complex day by day. Among different PET recycling methods, chemical recycling (chemolysis) is the most successful method to convert PET into its monomers/oligomers. This review presents in detail recent developments in the chemical recycling (glycolysis and aminolysis) of PET. The wide spectrum of depolymerizing agents used, the reaction conditions, catalysts, products of depolymerization, and their potential applications are described.
TL;DR: A simple preparation process was developed for magnetic nanoparticles, consisting of chitosan coated on Fe3O4 nanoparticle, to be used as support for enzyme immobilization.
Abstract: A simple preparation process was developed for magnetic nanoparticles, consisting of chitosan coated on Fe3O4 nanoparticles, to be used as support for enzyme immobilization. Cellulase was covalentl...
TL;DR: In this article, an Ag2O/g-C3N4 composite was applied in the photocatalytic degradation of phenol under UV- and visible-light irradiation.
Abstract: Ag2O/g-C3N4 composites synthesized in this study were applied in the photocatalytic degradation of phenol under UV- and visible-light irradiation. X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and transmission electron microscopy analysis demonstrated that Ag2O nanoparticles were well distributed on the surface of g-C3N4, and the heterostructure of Ag2O/g-C3N4 was formed. Compared with pure g-C3N4 and Ag2O, the Ag2O/g-C3N4 composite (8:1) displayed much higher photocatalytic activities in phenol degradation under UV- and visible-light irradiation. The degradation rate constant of 8:1 was 0.069 min–1 under visible light, which was almost 230 and 2.1 times more than that of pure g-C3N4 and Ag2O, respectively. Moreover, the formation of a certain amount of Ag0 on the surface of Ag2O under illumination contributed to the high stability of Ag2O/g-C3N4 photocatalysts. It was also found that photogenerated holes during the photocatalytic process played the predomin...
TL;DR: In this paper, Dy-doped ZnO nanoparticles were used for photocatalytic decolorization of C. I. acid red 17 solution under visible light irradiation.
Abstract: Dy-doped ZnO nanoparticles were synthesized with a sonochemical method. X-ray diffraction, inductively coupled plasma, Fourier transform infrared spectroscopy, UV–vis diffuse reflectance spectroscopy, and scanning electron microscopy analyses confirmed the successfully synthesis and nanometric diameter of the samples. Dy-doped ZnO nanoparticles were used for photocatalytic decolorization of C. I. Acid Red 17 solution under visible light irradiation. Among different amounts of dopant agent, 3% Dy-doped ZnO nanoparticles indicated the highest decolorization. Decolorization efficiency increased from 14.3 to 57.0% with an increase in catalyst dosage from 0.25 to 1 g/L, while further increment in the catalyst dosage up to 2 g/L caused an obvious decrease in decolorization efficiency. The addition of 0.1 mM peroxydisulfate (S2O82–) resulted in a decolorization efficiency of nearly 100% after irradiation for 180 min. The trend of inhibitory effect in the presence of different radical scavengers was Cl– > C2H5OH ...
TL;DR: In this article, field column experiments have been performed at the Marine Sciences Laboratory of the Pacific Northwest National Laboratory using a laboratory-proven, amidoxime-based polymeric adsorbent developed at the Oak Ridge National Laboratory (ORNL).
Abstract: Uranium recovery from seawater has been investigated for several decades for the purpose of securing nuclear fuel for energy production. In this study, field column experiments have been performed at the Marine Sciences Laboratory of the Pacific Northwest National Laboratory (PNNL) using a laboratory-proven, amidoxime-based polymeric adsorbent developed at the Oak Ridge National Laboratory (ORNL). The adsorbent was packed either in in-line filters or in flow-through columns. The maximum amount of uranium uptake from seawater was 3.3 mg of U/g of adsorbent after 8 weeks of contact between the adsorbent and seawater. This uranium adsorption amount was about 3 times higher than the maximum amount achieved in this study by a leading adsorbent developed at the Japan Atomic Energy Agency (JAEA). Both adsorbents were tested under similar conditions. The results were used to update an assessment of the cost of large-scale recovery of uranium from seawater using the ORNL adsorbent. The updated uranium production c...
TL;DR: In this paper, the Hansen solubility parameters (HSPs) of oxygen were determined from the measured solubilities in the pure solvents, where the HSPs of oxygen are δd = 6.7 MPa1/2, δp = 0.944 kPa, and δh = 3.8 MPa 1/2.
Abstract: The solubility of oxygen in 21 pure organic solvents was measured at 298.2 K and 101.33 kPa using the static method. The Hansen solubility parameters (HSPs) of oxygen were determined from the measured solubilities in the pure solvents. The HSPs of oxygen were δd = 6.7 MPa1/2, δp = 0.0 MPa1/2, and δh = 3.8 MPa1/2, where d, p, and h stand for dispersion forces, dipole interaction, and hydrogen bonding, respectively. A linear relationship between the log of the gas solubility (log xG) in pure solvents and the difference between the HSP values of oxygen and the pure solvents was obtained with a high correlation coefficient of 0.944. In addition, the solubilities of oxygen in mixed solvents were measured, and these were compared with the oxygen gas solubility calculated from the HSPs of oxygen.
TL;DR: In this paper, a detailed mechanistic model was developed for fast pyrolysis of neat glucose-based carbohydrates by integrating updated findings obtained through experiments and theoretical calculations, which described the decomposition of cellulosic polymer chains, reactions of intermediates, and formation of a range of low molecular weight compounds at the mechanistic level and specified each elementary reaction step in terms of Arrhenius parameters.
Abstract: Fast pyrolysis of lignocellulosic biomass, utilizing moderate temperatures ranging from 400 to 600 °C, produces a primary liquid product (pyrolytic bio-oil), which is potentially compatible with existing petroleum-based infrastructure and can be catalytically upgraded to fuels and chemicals. In this work, experiments were conducted with a micropyrolyzer coupled to a gas chromatography–mass spectrometry/flame ionization detector system to investigate fast pyrolysis of neat cellulose and other glucose-based carbohydrates. A detailed mechanistic model building on our previous work was developed for fast pyrolysis of neat glucose-based carbohydrates by integrating updated findings obtained through experiments and theoretical calculations. The model described the decomposition of cellulosic polymer chains, reactions of intermediates, and formation of a range of low molecular weight compounds at the mechanistic level and specified each elementary reaction step in terms of Arrhenius parameters. The mechanistic m...
TL;DR: In this article, surface-passivated photoluminescent carbon dots (CDs) were prepared via a facile one-step pyrolysis of poly(acrylic acid) (PAA) in the presence of glycerol.
Abstract: Surface-passivated photoluminescent carbon dots (CDs) were prepared via a facile one-step pyrolysis of poly(acrylic acid) (PAA) in the presence of glycerol. In the formation process of CDs, glycerol not only acts as solvent, but also promotes the carbonization of PAA (carbon source) and passivates the surface of CDs. The as-prepared CDs can emit bright-white fluorescence under ultraviolet (UV) illumination. The structure and optical properties of the CDs were thoroughly investigated. The CDs show excellent solubility in water and high photoluminescence stability in UV-radiation, salty, oxidic, or reductive environments, suggesting their great promise as white-light-emitting materials. For their practical applications, a white light-emitting diode (LED) with CDs as white-light converters was demonstrated. Moreover, a backlight with use of CDs as coatings was successfully constructed for the first time. This research would offer a promising new way to obtain white fluorescent CDs and suggests their strong p...
TL;DR: In this paper, a solution processable nanocomposite membrane prepared by incorporating functionalized graphene sheets (FGS) loaded in various concentrations into the chitosan matrix have been employed for the pervaporative dehydration of ethanol and isopropanol.
Abstract: Pervaporation is an important alternative membrane separation process compared to the distillation technique, and a relatively high separation factor is required to lower the energy demand. Solution processable nanocomposite membranes prepared by incorporating functionalized graphene sheets (FGS) loaded in various concentrations into the chitosan matrix have been employed for the pervaporative dehydration of ethanol and isopropanol. Incorporation of FGS leads to an increase of surface hydrophilicity of the chitosan membranes along with an increase in membrane tortuosity that was favorable to the selective permeation of water molecules. The nanocomposite membrane containing 2.5 wt % FGS gave the highest selectivities of 7781 and 1093 for isopropanol–water and ethanol–water mixtures, respectively, when tested for 10 wt % water-containing feed mixture. Membranes were characterized by wide-angle XRD, SEM, contact angle, and optical profilometry techniques. The Flory–Huggins theory was employed to estimate the...
TL;DR: In this paper, the authors presented an efficient visible light photocatalytic removal of gaseous NO at 600 ppb level with porous g-C3N4 nanostructures synthesized by pyrolysis of thiourea.
Abstract: Graphitic carbon nitride (g-C3N4) is an intriguing metal-free photocatalyst for pollution control. This research represents an efficient visible light photocatalytic removal of gaseous NO at 600 ppb level with porous g-C3N4 nanostructures synthesized by pyrolysis of thiourea. TG-DSC was employed to simulate the pyrolysis of thiourea, and the mechanistic formation process of g-C3N4 was revealed. The crystallinity, morphology, surface area, pore structures, band structure, and photocatalytic activity of g-C3N4 can be engineered by variation of pyrolysis temperature and time. A layer-by-layer coupled with layer-splitting process was proposed for the gradual reduction of layer thickness and size of g-C3N4 obtained at elevated temperature and prolonged time. The visible light photocatalytic activity of g-C3N4 nanosheets toward NO purification was significantly enhanced due to the enhanced crystallinity, nanosheet structure, large surface areas and pore volume and enlarged band gap as the pyrolysis temperature ...
TL;DR: In this article, the effects of lamp choice, concentration of catalyst, and methylene blue were analyzed, and experimental data was fitted to a pseudo-first-order model with sufficient accuracy.
Abstract: The application of semiconductors in water treatment via photocatalysis of various pollutants has attracted much attention from researchers. In this work, photocatalytic degradation of methylene blue by P25 titanium dioxide was studied experimentally and then via modeling. The effects of lamp choice, concentration of catalyst, and methylene blue were analyzed. Desorption of methylene blue at the start of light radiation was observed, and analyzed in detail for the first time. Both desorption and degradation processes were modeled, and experimental data was fitted to a pseudo-first-order model with sufficient accuracy. The effects of catalyst and initial dye concentration on reaction rate constants were discussed.
TL;DR: In this paper, a low-cost and simple process was used to fabricate a silver-polyaniline/multiwalled carbon nanotubes ((Ag-PANI)/MWCNTs) nanocomposite for high-performance supercapacitor electrodes.
Abstract: In the modern era, it is still a challenge to develop an easy, inexpensive, and scalable technique to fabricate an energy storage system. Here, a low-cost and simple process was used to fabricate a silver–polyaniline/multiwalled carbon nanotubes ((Ag-PANI)/MWCNTs) nanocomposite for high-performance supercapacitor electrodes. The possible interactions between Ag and PANI were characterized by Fourier transform infrared and UV–visible spectroscopies. Morphological study confirmed the formation of Ag nanoparticles in the PANI surface, and the MWCNTs were uniformly coated by PANI with the presence of Ag nanoparticles. The nanocomposite showed better electrical conductivity of 4.24 S/cm at room temperature and also attained nonlinear current–voltage characteristics. The highest specific capacitance of 528 F/g has been obtained for the nanocomposite at 5 mV/s scan rate. The nanocomposite also showed better energy as well as power density. Ag-PANI/CNT based supercapacitors with outstanding energy and power densi...
TL;DR: In this paper, high conductive pristine graphene electrodes were fabricated by inkjet printing using ethyl cellulose-stabilized ink prepared from pristine graphene, which was generated by exfoliation from graphite using ultrasound-assisted supercritical CO2.
Abstract: Highly conductive pristine graphene electrodes were fabricated by inkjet printing using ethyl cellulose-stabilized ink prepared from pristine graphene. Pristine graphene was generated by exfoliation from graphite using ultrasound-assisted supercritical CO2. The ink, at concentrations up to 1 mg/mL, was stable for more than 9 months and had compatible fluidic characteristics for efficient and reliable inkjet printing. The inkjet printing patterns of the graphene on diverse substrates were uniform and continuous. After 30 printing passes and annealing at 300 °C for 30 min, the printed films developed a high conductivity of 9.24 × 103 S/m. The resistivity of the printed electrodes on the flexible substrates increased by less than 5% after 1000 bending cycles and by 5.3% under a folding angle of 180°. The presented exfoliated pristine graphene and the corresponding efficient methods for formulating the ink and fabricating conductive electrodes are expected to have high potential in applications involving grap...
TL;DR: In this paper, the authors summarized the recent advances in IL research as dual-function gas hydrate inhibitors and evaluated the efficiency of ILs in gas hydrate inhibition, compared to other conventional thermodynamic and kinetic GH inhibitors.
Abstract: Ionic liquids (ILs) are popular designer green chemicals with great potential for use in diverse energy-related applications. Apart from the well-known low vapor pressure, the physical properties of ILs, such as hydrogen-bond-forming capacity, physical state, shape, and size, can be fine-tuned for specific applications. Natural gas hydrates are easily formed in gas pipelines and pose potential problems to the oil and natural gas industry, particularly during deep-sea exploration and production. This review summarizes the recent advances in IL research as dual-function gas hydrate inhibitors. Almost all of the available thermodynamic and kinetic inhibition data in the presence of ILs have been systematically reviewed to evaluate the efficiency of ILs in gas hydrate inhibition, compared to other conventional thermodynamic and kinetic gas hydrate inhibitors. The principles of natural gas hydrate formation, types of gas hydrates and their inhibitors, apparatuses and methods used, reported experimental data, a...
TL;DR: In this paper, the effect of the duration of ultrasonic treatment on colloidal structure, including the stability and temperature-dependent viscosity of a nanofluid, was studied.
Abstract: Nanofluids are promising fluids for heat-transfer applications. Low stability and high viscosity are two important drawbacks for practical applications of nanofluids. The aggregation and sedimentation of nanoparticles are related to the colloidal structure of nanofluids, which directly affects the stability and viscosity. An ultrasonic homogenizer can break the aggregation of particles. The aim of this work was to study the effect of the duration of ultrasonic treatment on colloidal structure, including the stability and temperature-dependent viscosity of a nanofluid. Specifically, a 0.5 vol % Al2O3–water nanofluid was prepared using an ultrasonic homogenizer for various durations from 0 to 180 min. The microstructure, colloid and particle sizes, precipitation, and zeta (ζ) potential were analyzed to investigate the aggregation and sedimentation of the nanofluid. The viscosities of nanofluids subjected to ultrasonic treatment for different durations were also measured at different temperatures from 15 to ...
TL;DR: The role of silver content on the properties of photocatalyst has been studied in this paper, where the silver-doped titanium dioxide (Ag-TiO2) photocatalysts with varied silver content ranging from 0.75 at % to 3.5 at % were synthesized by a single-step sol-gel method.
Abstract: The silver-doped titanium dioxide (Ag–TiO2) photocatalysts with varied silver content ranging from 0.75 at % to 3.5 at % were synthesized by a single-step sol–gel method. The role of silver content on the properties of photocatalyst has been studied. The doping of 0.75 at % silver in TiO2 produced thermally stable TiO2 anatase phase with smallest particle size, uniform particles size and morphology, high surface area and low-energy excitation characteristics. The Ag–TiO2 sample with 0.75 at % silver possesses predominantly finely dispersed silver species (Ag2O and AgO) on the surface. The proportion of surface agglomerated silver metal (Ag0) increases as the silver content in the Ag–TiO2 sample increases. The silver oxide species were observed to be responsible for better physicochemical and catalytic properties. The TiO2 with 0.75 at % silver was found to be an efficient photocatalyst showing enhanced photocatalytic activity for aqueous medium photocatalytic degradation of phthalic acid in the presence o...
TL;DR: In this paper, a new nanoporous magnetic cellulose-chitosan composite microspheres (NMCMs) were prepared by sol-gel transition method using ionic liquids as solvent for the sorption of Cu(II).
Abstract: Novel nanoporous magnetic cellulose–chitosan composite microspheres (NMCMs) were prepared by sol–gel transition method using ionic liquids as solvent for the sorption of Cu(II). The composite microspheres were studied by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), X-ray diffraction (XRD), and vibrating sample magnetometry (VSM). Subsequelty, the adsorption of Cu(II) to NMCMs was investigated systematically with varried parameters such as pH, contact time, and initial concentration. Results revealed that the composite microspheres exhibited efficient adsorption capacity of Cu(II) from aqueous solution, due to their favorable chelating groups in structure. The adsorption process was best described by a pseudo-second-order kinetic model, while isotherm modeling revealed that the Langmuir equation better describe the adsorption of Cu(II) on NMCMs as compared to Freundlich model. Moreover, the loaded NMCMs can be easily regenerated with ...
TL;DR: A series of Zn-modified nano-HZSM-5 (Zn/NZ) catalysts were prepared and used in the conversion of methanol to light aromatics (benzene, toluene, and xylene; BTX) as mentioned in this paper.
Abstract: A series of Zn-modified nano-HZSM-5 (Zn/NZ) zeolite catalysts were prepared and used in the conversion of methanol to light aromatics (benzene, toluene, and xylene; BTX). The reaction conditions and loading of Zn exhibited a significant influence on the BTX yield. The interaction of Zn species with hydroxyl groups (OH) occurred on the HZSM-5 surface with the loading of Zn on a HZSM-5 zeolite. Such interaction distinctly changed the texture and acidity of the Zn/HZSM-5 catalyst. On the other hand, reduction of the Zn/NZ crystal size not only improved the interaction of the Zn species with HZSM-5 but also enhanced the resistance of coke deposition. The high BTX yield of 67.7% and good catalytic stability were obtained on a 0.5 wt % Zn/NZ catalyst, mainly because of its proper concentration and distribution of acid sites as well as the small crystal size with improved physical transport.
TL;DR: Guaiacol, a phenol derived compound produced by the thermal degradation of lignin, was selected as a model compound to study the catalytic hydrodeoxygenation (HDO) process for upgrading pyrolysis bio-oils as mentioned in this paper.
Abstract: Guaiacol, a phenol derived compound produced by the thermal degradation of lignin, was selected as a model compound to study the catalytic hydrodeoxygenation (HDO) process for upgrading pyrolysis bio-oils. Guaiacol is among the major components of bio-oils; however, it is thermally unstable which leads to catalyst deactivation. In the present study, four noble metal catalysts (Pt, Pd, Rh, and Ru) supported on activated carbon were tested in a fixed-bed reactor at atmospheric pressure and their performance for the guaiacol HDO process was measured. Our results showed that, among the tested catalysts, Pt has higher deoxygenation activity and shows little deactivation for 5 h. Additionally, the operating temperature for the Pt catalyst was optimized and found to be 300 °C. Finally, results from catalyst characterization demonstrated that polyaromatic deposits, especially the condensed ring compounds, are the most likely cause for catalyst deactivation.