Showing papers in "Industrial & Engineering Chemistry Research in 2012"
TL;DR: In this article, a variety of promising sorbents such as activated carbonaceous materials, microporous/mesoporous silica or zeolites, carbonates, and polymeric resins loaded with or without nitrogen functionality for the removal of CO2 from the flue gas streams have been reviewed.
Abstract: Post-combustion CO2 capture from the flue gas is one of the key technology options to reduce greenhouse gases, because this can be potentially retrofitted to the existing fleet of coal-fired power stations. Adsorption processes using solid sorbents capable of capturing CO2 from flue gas streams have shown many potential advantages, compared to other conventional CO2 capture using aqueous amine solvents. In view of this, in the past few years, several research groups have been involved in the development of new solid sorbents for CO2 capture from flue gas with superior performance and desired economics. A variety of promising sorbents such as activated carbonaceous materials, microporous/mesoporous silica or zeolites, carbonates, and polymeric resins loaded with or without nitrogen functionality for the removal of CO2 from the flue gas streams have been reviewed. Different methods of impregnating functional groups, including grafting techniques and modifying the support materials, have been discussed to en...
1,502 citations
TL;DR: In this article, the authors provide a detailed overview of the achievements and difficulties that has been encountered in finding a suitable ionic liquid for CO2 capture from flue-gas streams.
Abstract: Economical and environmental aspects are the main motivation for research on energy efficient processes and the search for environment friendly materials for CO2 capture. Currently, CO2 capture is dominated by amine-based (e.g., monoethanolamine) technologies, which are very energy intensive and less attractive from an environmental point of view due to emissions of the used volatile solvent components. Ionic liquids have been proposed as a promising alternative to the conventional volatile solvents, because of their low volatility and other interesting properties. This remarkable interest has led to a rapid growth of literature on this specific subject. The aim of the present review paper is to provide a detailed overview of the achievements and difficulties that has been encountered in finding a suitable ionic liquid for CO2 capture from flue-gas streams. A major part of this review includes an overview of the experimental data of CO2 solubility, selectivity, and diffusivity in different ionic liquids. ...
866 citations
TL;DR: In this paper, the chemical and structural properties of cellulose, lignin, d-xylose, wood meal, and phenolic hydrochars were investigated, and the carbonization mechanism was proposed, and furfural was found to be an important intermediate product during d-Xylose hydrochar production.
Abstract: Hydrothermal carbonization of cellulose, lignin, d-xylose (substitute for hemicellulose), and wood meal (WM) was experimentally conducted between 225 and 265 °C, and the chemical and structural properties of the hydrochars were investigated. The hydrochar yield is between 45 and 60%, and the yield trend of the feedstock is lignin > WM > cellulose > d-xylose. The hydrochars seem stable below 300 °C, and aromatic structure is formed in all of these hydrochars. The C content, C recovery, energy recovery, ratio of C/O, and ratio of C/H in all of these hydrochars are among 63–75%, 80–87%, 78–89%, 2.3–4.1, and 12–15, respectively. The higher heating value (HHV) of the hydrochars is among 24–30 MJ/kg, with an increase of 45–91% compared with the corresponding feedstock. The carbonization mechanism is proposed, and furfural is found to be an important intermediate product during d-xylose hydrochar production, while lignin hydrothermal carbonization products are made of polyaromatic hydrochar and phenolic hydrocha...
548 citations
TL;DR: In this article, water adsorption in metal-organic frameworks (MOFs) at room temperature and up to 90% relative humidity was investigated. But the results were limited to the case of Zn-COOH containing MOFs (DMOF-1; DMOF1-NH2; UMCM-1).
Abstract: This work presents an experimental investigation of water adsorption in metal–organic frameworks (MOFs) at room temperature and up to 90% relative humidity. Structural degradation of the materials after regeneration is analyzed via powder X-ray diffraction (PXRD) and nitrogen adsorption measurements. MOFs with open metal sites are quite hydrophilic but appear to maintain their structure according to PXRD. However, significant surface area loss indicates that decomposition is occurring and is likely an attribute of oxygen presence during the regeneration procedure. Materials with copper paddle-wheel (HKUST-1), 5-coordinated magnesium (Mg MOF-74), and 7-coordinated zirconium (UiO-66(-NH2)) maintain good structural stability, while Zn-COOH containing MOFs (DMOF-1; DMOF-1-NH2; UMCM-1) undergo complete loss of crystallinity.
462 citations
TL;DR: A review of recent progress on MOF membranes with an emphasis on their fabric can be found in this paper, where the authors discuss the challenges associated with fabricating films of MOF materials, including poor substrate-film interactions, moisture sensitivity, and thermal/mechanical instability.
Abstract: Metal–organic frameworks (MOFs) are hybrid organic–inorganic nanoporous materials that exhibit regular crystalline lattices with relatively well-defined pore structures. Chemical functionalization of the organic linkers in the structures of MOFs affords facile control over pore size and chemical/physical properties, making MOFs attractive for a variety of industrial applications including membrane-based gas separations. A wealth of reports exists discussing the synthesis and applications of MOFs; however, relatively few reports exist discussing MOF membranes. This disparity owes to challenges associated with fabricating films of MOF materials, including poor substrate–film interactions, moisture sensitivity, and thermal/mechanical instability. Since even nanometer-scale cracks and defects can affect the performance of a membrane for gas separation, these challenges are particularly acute for the fabrication of MOF membranes. Here, we review recent progress on MOF membranes with an emphasis on their fabric...
456 citations
TL;DR: In this article, the Ni/Al2O3 catalysts for synthetic natural gas production were systematically investigated by tuning a number of parameters, including NiO and MgO loading, calcination temperature, space velocity, H2/CO ratio, reaction pressure, and time.
Abstract: CO methanation reaction over the Ni/Al2O3 catalysts for synthetic natural gas production was systematically investigated by tuning a number of parameters, including using different commercial Al2O3 supports and varying NiO and MgO loading, calcination temperature, space velocity, H2/CO ratio, reaction pressure, and time, respectively. The catalytic performance was greatly influenced by the above-mentioned parameters. Briefly, a large surface area of the Al2O3 support, a moderate interaction between Ni and the support Al2O3, a proper Ni content (20 wt %), and a relatively low calcination temperature (400 °C) promoted the formation of small NiO particles and reducible β-type NiO species, which led to high catalytic activities and strong resistance to the carbon deposition, while addition of a small amount of MgO (2 wt %) could improve the catalyst stability by reducing the carbon deposition; other optimized conditions that enhanced the catalytic performance included high reaction pressure (3.0 MPa), high H2...
256 citations
TL;DR: In this paper, the potential of using hydrophilic cellulose acetate propionate (CAP) as microporous substrates for the fabrication of thin-film composite (TFC) forward osmosis (FO) membranes has been explored.
Abstract: For the first time, the potential of using hydrophilic cellulose acetate propionate (CAP) as microporous substrates for the fabrication of thin-film composite (TFC) forward osmosis (FO) membranes has been explored. Two types of TFC flat sheet membranes with well-designed substrate structures were prepared. The CAP-TFC membranes show very low Js/Jw ratios (i.e., the ratio of reverse draw solute flux to water flux) of about 0.05 g/L with reasonably high water fluxes under the pressure-retarded osmosis (PRO) mode using 2 M NaCl as the draw solution and deionized water as the feed. When using model seawater as the feed, the water flux is about 12.3 LMH which is comparable to the best in the literature. These results, combined with positron annihilation spectroscopy (PAS) data, confirm the hypothesis that a finger-like morphology in the substrate is not crucial to the performance of TFC FO membranes. Moreover, the surface and skin morphology of the substrate may play essential roles in the formation of the pol...
230 citations
TL;DR: In this article, the synthesis of Co3O4-reduced graphene oxide (rGO) hybrids and the catalytic performance in heterogeneous activation of peroxymonosulfate (PMS) for the decomposition of phenol were reported.
Abstract: This paper reports the synthesis of Co3O4–reduced graphene oxide (rGO) hybrids and the catalytic performance in heterogeneous activation of peroxymonosulfate (PMS) for the decomposition of phenol. The surface morphologies and structures of the Co3O4–rGO hybrids were investigated by field emission scanning electron microscopy (SEM), energy-dispersive X-ray spectrometer (EDS), transmission electron microscopy (TEM), powder X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). Through an in situ chemical deposition and reduction, Co3O4–rGO hybrids with Co3O4 nanoparticles at an average size of 33 nm were produced. Catalytic testing showed that 20 mg/L of phenol could be completely oxidized in 20 min at 25 °C on Co3O4–rGO hybrids, which is mostly attributed to the generation of sulfate radicals through Co3O4-mediated activation of PMS. Phenol oxidation was fitted by a pseudo-zero-order kinetic model. The rate constant was found to in...
229 citations
TL;DR: Sunlight-induced photodegradation of rhodamine B over Ag3PO4 has been observed in this article, where the phase structure, morphology, and optical properties of the product were investigated.
Abstract: Sunlight-induced photodegradation of rhodamine B over Ag3PO4 has been observed. Nanosized Ag3PO4 was synthesized by a facile ion-exchange route. X-ray powder diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, the Brunauer–Emmett–Teller surface area, UV–vis diffuse reflectance spectroscopy and photoluminescence spectra were employed to investigate the phase structure, morphology and optical property of the Ag3PO4 product. Nearly 100% of rhodamine B was degraded after a very short irradiation time using simulated sunlight in Ag3PO4 suspension, and the total organic carbon measurement revealed that a high degree of mineralization was achieved in the present photocatalytic system. Ag3PO4 catalyst has an excellent photocatalytic performance due to the high separation efficiency of electron and hole pairs. In the neutral pH solution, Ag3PO4 catalyst exhibited the best photoactivity under simulated sunlight. The photoinduced holes were considered to be the dominant active species in the...
223 citations
TL;DR: In this article, a new Fe-Mn mixedoxide catalysts were prepared for the low-temperature selective catalytic reduction (SCR) of NOx with ammonia in the presence of excess oxygen.
Abstract: Novel Fe–Mn mixed-oxide catalysts were prepared for the low-temperature selective catalytic reduction (SCR) of NOx with ammonia in the presence of excess oxygen. It was found that Fe(0.4)–MnOx catalyst showed the highest activity, yielding 98.8% NOx conversion and 100% selectivity of N2 at 120 °C at a space velocity of 30 000 h–1. XRD results suggested that a new crystal phase of Fe3Mn3O8 was formed in the Fe–MnOx catalysts. TPR and Raman data showed that there was a strong interaction between the iron oxide and manganese oxide, which is responsible for the formation of the active center―Fe3Mn3O8. Intensive analysis of fresh, used, and regenerated catalysts by XPS revealed that electron transfer between Fen+ and Mnn+ ions in Fe3Mn3O8 may account for the long lifetime of the Fe(0.4)–MnOx catalyst. In addition, the SCR activity was suppressed a little in the presence of SO2 and H2O, but it was reversible after their removal.
221 citations
TL;DR: In this article, the photocatalytic activity of Bi2O2CO3/BiOI composites was evaluated through the photocleaning of wastewater which contained rhodamine-B, methylene blue, crystal violet, or a mixture of them under visible-light irradiation (λ ≥ 420 nm).
Abstract: Bi2O2CO3/BiOI composites were fabricated at room temperature for the first time by a facile method. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV–vis diffuse reflectance spectra (UV–vis DRS), and nitrogen adsorption–desorption techniques were employed to characterize the physiochemical properties of the composites. The photocatalytic activities of Bi2O2CO3, BiOI, and Bi2O2CO3/BiOI were evaluated through the photocleaning of wastewater which contained rhodamine-B, methylene blue, crystal violet, or a mixture of them under visible-light irradiation (λ ≥ 420 nm). The photocatalytic activity of Bi2O2CO3/BiOI is much higher than that of its components. Moreover, the composite shows good photostability and recyclability. The excellent catalytic efficiency of the Bi2O2CO3/BiOI composite is deduced closely related to Bi2O2CO3/BiOI heterojunctions whose presence is generally regarded to be a favorable factor for the s...
TL;DR: In this article, the authors used COSMOtherm as a powerful and rapid tool to calculate free volumes in 165 existing and theoretical 1-n-alkyl-3-methylimidazolium ([Cnmim][X]) ILs, a previously unreported, yet speculated, critical underlying relationship between gas solubility in ILs is described.
Abstract: While molar volume-based models for gas solubility in ionic liquids (ILs) have been proposed, free volume within the IL can be shown to be the underlying property driving gas solubility and selecitivity. Previously published observations as to the distinct differences in solubility trends for gases such as CH4 and N2 relative to CO2 in systematically varied ILs can be attributed to positive and negative effects arising from increasing free volume with increasing alkyl chain length. Through the use of COSMOtherm as a powerful and rapid tool to calculate free volumes in 165 existing and theoretical 1-n-alkyl-3-methylimidazolium ([Cnmim][X]) ILs, a previously unreported, yet speculated, critical underlying relationship between gas solubility in ILs is herein described. These results build upon previous assertions that Regular Solution Theory is applicable to imidazolium-based ILs, which appeared to indicate that a global maximum had already been observed for CO2 solubility in imidazolium-based ILs. However, ...
TL;DR: In this paper, low-cost pine wood and pine bark chars, obtained as a byproduct from fast pyrolysis in an auger reactor at 400 and 450 °C, were characterized and used as received for water defluoridation.
Abstract: Drinking water containing fluoride >1 mg/L is unsafe for human consumption. Higher intake of fluoride can cause potential health hazards. Low-cost pine wood and pine bark chars, obtained as a byproduct from fast pyrolysis in an auger reactor at 400 and 450 °C, were characterized and used as received for water defluoridation. Sorption studies were performed at different temperatures, pH values, and solid to liquid ratios in the batch mode. Maximum fluoride adsorption occurred at pH 2.0. A kinetic study yielded an optimum equilibrium time of 48 h with an adsorbent dose of 10 g/L. Sorption isotherm studies were conducted over a concentration range of 1–100 mg/L. Fluoride adsorption decreased with an increase in temperature. The char performances were evaluated using the Freundlich, Langmuir, Redlich–Peterson, Toth, Temkin, Sips, and Radke adsorption models. Based on average percent error, the best isotherm fits follow the orders for pine wood and pine bark: PWLangmuir ≈ PWRedlich-Peterson > PWToth > PWSips >...
TL;DR: In this article, metal oxides are reviewed as catalysts to convert H2O and CO2 to fuels using solar energy, and examples of high-temperature solar reactors driven by concentrated solar radiation are presented.
Abstract: Metal oxides are reviewed as catalysts to convert H2O and CO2 to fuels using solar energy. For photochemical conversion, TiO2 has been found to be the most stable and useful oxide material, but it is currently limited by its large bandgap and a mismatch between its conduction band and the redox couples for water splitting and CO2 reduction. A theoretical framework has been utilized to understand the basic thermodynamics and energetics in photochemical energy conversion systems. This is applied to model systems comprised of Ag2O and AgCl to examine why the former reacts thermochemically in air, while the latter reacts photochemically. For thermochemical conversion, zinc-, ceria-, and ferrite-based redox cycles are examined and examples of high-temperature solar reactors driven by concentrated solar radiation are presented. For CO2 splitting, theoretical solar-to-fuel energy conversion efficiencies can be up to 26.8% for photochemical systems, and can exceed 30% for thermochemical systems, provided that sen...
TL;DR: In this paper, the corrosion inhibition of low carbon steel in 1 M HCl solution with different concentrations of Schinopsis lorentzii extract was studied using Tafel extrapolation, linear polarization, and electrochemical impedance spectroscopy (EIS).
Abstract: The corrosion inhibition of low carbon steel in 1 M HCl solution with different concentrations of Schinopsis lorentzii extract was studied using Tafel extrapolation, linear polarization, and electrochemical impedance spectroscopy (EIS). It was found that Schinopsis lorentzii extract acted as slightly cathodic inhibitor and inhibition efficiencies increased with the increase of extract concentration. The adsorption of the molecules of the extract on the low carbon steel surface was in accordance with the Temkin adsorption isotherm. The results showed that Schinopsis lorentzii extract could serve as a corrosion inhibitor of the low carbon steel in hydrochloric acid environment.
TL;DR: In this article, an effective methodology for the detoxification of chromium using cellulose-montmorillonite composite material as the adsorbent was reported, which exhibited a maximum adsorption capacity of 22.2 mg g−1 in accordance with the Langmuir isotherm model.
Abstract: Biopolymer composites are known for their utility in diverse applications. In this paper, we report an effective methodology for the detoxification of chromium using cellulose-montmorillonite composite material as the adsorbent. The interaction of surfactant modified sodium montmorillonite (NaMMT) with cellulose biopolymer is followed by the subsequent adsorption of Cr(VI) from aqueous solution as bichromate anion onto the surface of the biocomposite material. The composite adsorbent was characterized comprehensively using Fourier transform infrared spectroscopy (FT-IR), Energy dispersive X-ray spectrometry (EDX), X-ray diffraction (XRD) and Branauer-Emmett-Teller (BET) isotherm studies. The material exhibited a maximum adsorption capacity of 22.2 mg g–1 in accordance with the Langmuir isotherm model. The mesoporous nature of the material was ascertained from the nitrogen adsorption isotherm study and the adsorption process was in accordance with second order kinetics. The spontaneity of the adsorption pr...
TL;DR: In this paper, DOPO has been grafted onto the surface of graphene oxide (GO) by reacting epoxy ring groups together with the reduced graphene structure (DOPO-rGO).
Abstract: 9,10-Dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) has been grafted onto the surface of graphene oxide (GO) by reacting epoxy ring groups together with the reduced graphene structure (DOPO-rGO). X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, and UV–vis spectroscopy confirm that DOPO not only covalently bonded to the GO, as a functionalization moiety, but also partly restored the conjugate structure of GO, as a reducing agent. A pelletlike structure of DOPO on rGO sheets was observed by means of transmission electron microscopy (TEM), contributing to good dispersion of rGO in nonpolar toluene. Furthermore, the flame retardancy and thermal stability of DOPO-rGO/epoxy nanocomposites containing various weight fractions of DOPO-rGO were investigated by the limiting oxygen index (LOI) test and thermogravimetric analysis (TGA) in nitrogen. Significant increases in the char yield and LOI were achieved with the addition of...
TL;DR: In this paper, the synthesis of magnetic CoFe2O4-reduced graphene oxide (rGO) hybrids and the catalytic performance in heterogeneous activation of peroxymonosulfate (PMS) for decomposition of p...
Abstract: This paper reports the synthesis of magnetic CoFe2O4–reduced graphene oxide (rGO) hybrids and the catalytic performance in heterogeneous activation of peroxymonosulfate (PMS) for decomposition of p...
TL;DR: In this article, the conditions under which Fe(II) activates Na2SO3 to produce SO4•− and decolorize organic dyes were investigated, and detailed mechanisms of the Fe (II)/sulfite system were researched.
Abstract: A novel process for decolorizing dyes with sulfate radicals (SO4•–) using an Fe(II)/sulfite system is reported in this manuscript. The objective of this study was to investigate the conditions under which Fe(II) activates Na2SO3 to produce SO4•– and decolorize organic dyes. Orange II, Rhodamine B, Indigo Carmine, and Reactive Brilliant Blue X-BR could be efficiently decolorized using this novel system, which was compared with the Fe(II)/persulfate and Fenton (Fe(II)/H2O2) systems. The Fe(II)/sulfite system surpassed the other two in the decolorization of these dyes, and detailed mechanisms of the Fe(II)/sulfite system were researched. Primary radical identification through quenching experiments using tert-butyl alcohol and ethanol confirmed the existence of SO4•–, HO•, and SO5•–. A kinetic model was established for the halide ion effect, and kI–,SO4•– (3.2 × 1011 mol–1 L s–1) and RSO4•–f (10–4–10–3 mol L–1 s–1) were indirectly derived. In conclusion, the Fe(II)/sulfite system is a good candidate for use i...
TL;DR: In this article, a straightforward strategy is designed for the fabrication of CuFe2O4-graphene heteroarchitecture via a one-step hydrothermal route to allow multifunctional properties, i.e., magnetic cycling, high photocatalytic activity under visible light irradiation, and excellent electrochemical behaviors for use as the anode in lithium-ion batteries (LIBs).
Abstract: A straightforward strategy is designed for the fabrication of CuFe2O4-graphene heteroarchitecture via a one-step hydrothermal route to allow multifunctional properties, i.e., magnetic cycling, high photocatalytic activity under visible light irradiation, and excellent electrochemical behaviors for use as the anode in lithium-ion batteries (LIBs). Transmission electron microscopy (TEM) observations indicate that graphene sheets are exfoliated and decorated with hexagonal CuFe2O4 nanoflakes. The photocatalytic activity measurements demonstrate that the combination of CuFe2O4 and graphene results in a dramatic conversion of the inert CuFe2O4 into a highly active catalyst for the degradation of methylene blue (MB) under visible light irradiation. CuFe2O4 nanoparticles themselves have excellent magnetic properties, which makes the CuFe2O4-graphene heteroarchitecture magnetically recyclable in a suspension system. It should be pointed out that the CuFe2O4-graphene (with 25 wt % graphene) heteroarchitecture as a...
TL;DR: In this article, flexible crystalline metal-organic framework (MOF) of nanosize particles (Al-MIL-53) and 6FDA-ODA polyimides were used to produce mixed matrix membranes (MMM).
Abstract: Flexible crystalline metal–organic framework (MOF) of nanosize particles (Al-MIL-53) and 6FDA-ODA polyimides were used to produce mixed matrix membranes (MMM). These MMM display excellent CO2/CH4 separation properties even without any compatibilization (amine grafting). The ideal selectivity and separation factor were found to increase with increasing MOF loading. Furthermore, these materials have an improved CO2/CH4 separation factor with increasing pressure, in contrast to traditional polymer membranes.
TL;DR: In this paper, the authors highlight the potential use of waste cooking oil as a cheap and economical feedstock discussing the advantages of the process and limitations for transesterification reaction and discuss improvements in the synthesis process based on the different pretreatment methods and process intensifying techniques.
Abstract: The use of biodiesel as an alternative fuel has become more attractive recently because of its environmental benefits such as nontoxicity and biodegradability. However, due to the unfavorable economics and other problems for design and operation of large scale reactors, commercialization of biodiesel has not been significantly effective. The specific challenges in the synthesis route based on transesterification include higher separation times, high operating cost, high energy consumption, and low production efficiency due to equilibrium limitations. The present work highlights the potential use of waste cooking oil as a cheap and economical feedstock discussing the advantages of the process and limitations for transesterification reaction. Improvements in the synthesis process based on the different pretreatment methods and process intensifying techniques are discussed with specific reference to transesterification of waste cooking oil. Different physical and chemical pretreatment methods required for th...
TL;DR: In this article, experimental measurements and molecular dynamics simulations are used to determine the density, heat capacity, self-diffusivity, shear viscosity, and thermal conductivity of six ionic liquids over a range of temperatures.
Abstract: Experimental measurements and molecular dynamics simulations are used to determine the density, heat capacity, self-diffusivity, shear viscosity, and thermal conductivity of six ionic liquids over a range of temperatures. The ionic liquids examined are 1-butyl-3-methylimidazolium bis[(perfluoroethyl)sulfonyl]imide ([bmim][Pf2N]), 1-butyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide ([bmim][Tf2N]), 1-butyl-2,3-dimethylimidazolium bis[(trifluoromethyl)sulfonyl]imide ([bmmim][Tf2N]), 1-butyl-1-methylpyrrolidinium bis[(trifluoromethyl)sulfonyl]imide ([bmpyr][Tf2N]), N-butyl-N,N,N-trimethylammonium bis[(trifluoromethyl)sulfonyl]imide ([N4111][Tf2N]), and N,N,N-trimethylammonium-N-butanoic acid bis[(trifluoromethyl)sulfonyl]imide ([N4111][COOHTfN]). The results of this work suggest that several of these ionic liquids have properties that would enable them to be successful high temperature heat transfer fluids. In particular, their energy storage densities and thermal conductivities are quite favorabl...
TL;DR: In this article, a novel nitrogen-phosphorus flame retardant, 2-carboxyethyl(phenyl)phosphinic acid melamine salt (CMA), was synthesized by the reaction of 2-CARBOXyethyl (phenyl)-phosphinic acid with melamine in aqueous solution, and it was characterized by Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR), inductively coupled plasma-atomic emission spectrometry (ICP-AES), elemental analysis, and thermogravim
Abstract: A novel nitrogen–phosphorus flame retardant, 2-carboxyethyl(phenyl)phosphinic acid melamine salt (CMA), was synthesized by the reaction of 2-carboxyethyl(phenyl)phosphinic acid with melamine in aqueous solution, and it was characterized by Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR), inductively coupled plasma-atomic emission spectrometry (ICP-AES), elemental analysis, and thermogravimetric analysis (TGA). Halogen-free flame-retardant flexible polyurethane foams (FPUF) were prepared successfully by using CMA as a flame retardant. The effects of CMA content on the mechanical, thermal, and flame-retardant properties of FPUF were investigated by tensile test, TGA, limiting oxygen index (LOI), flame propagation test (Cal T.B. 117A-Part I standard), and cone calorimeter. The foam morphology of FPUF was studied via scanning electron microscopy (SEM). The results showed that CMA endowed FPUF with good flame-retardant properties. FPUF containing only 12 wt % CMA can pass Cal ...
TL;DR: In this article, the conditions for facile, mild, and selective masking of the phenolic hydroxyl groups in softwood and hardwood kraft lignins were examined.
Abstract: This work offers a comprehensive understanding of the conditions required for the selective masking of the phenolic hydroxyl groups in technical kraft lignins, which is pivotal in determining their subsequent chemical and thermal reactivity. To this effect, we have examined the chemistry and developed the conditions for the facile, mild, and selective masking of the phenolic hydroxyl groups in softwood and hardwood kraft lignins. We have compared two series of methylated softwood kraft lignins synthesized using different methylation chemistries. Our data show that (when used as specified) dimethyl sulfate in aqueous NaOH selectively converts the phenolic hydroxyl groups of kraft lignin to its methylated derivatives without apparent side reactions. In contrast, methyl iodide (in the presence of excess K2CO3 in N,N-dimethylformamide) was found to be rather ineffective and unselective. Various milder methylation conditions were also examined for both softwood and hardwood kraft lignins using dimethyl sulfate, and the details of this work are documented. In addition, a series of oxypropylation reactions were also carried out using propylene oxide in aqueous NaOH. Propylene oxide was shown to selectively add (at room temperature, 0.5 M NaOH, 18 h) less than two units on average per phenolic hydroxyl group without significant additional polymerization or other side reactions.
TL;DR: In this paper, the dye-sensitization technique was applied to prepare visible light-active catalyst and used it under visible solar light generated from a solar simulator with a UV cutoff filter (λ > 420 nm).
Abstract: Phenol degradation with TiO2 photocatalyst under UV light is known to be an effective method. Under solar radiation, however, this approach does not receive adequate photons for catalyst activation, as the solar spectrum comprises mostly visible light (46%). In this study, we applied the dye-sensitization technique to prepare visible-light-active catalyst and used it under visible solar light generated from a solar simulator with a UV cutoff filter (λ > 420 nm) for phenol degradation. Eosin Y dye was used as a sensitizer for the TiO2 catalyst with a very low level of platinum as a cocatalyst. Triethanolamine was used as a sacrificial electron donor. Parametric studies were performed for the catalyst loading, initial triethnolamine concentration, initial phenol concentration, platinum content on TiO2, solution pH, and visible light intensity. About 93% degradation of 40 ppm phenol solution was achieved within 90 min using Eosin Y–TiO2/Pt photocatalyst under optimum conditions (pH 7.0, catalyst loading of 0...
TL;DR: In this article, a simple and straightforward strategy was developed to fabricate magnetically separable MnFe2O4-graphene photocatalysts with differing graphene content.
Abstract: A simple and straightforward strategy was developed to fabricate magnetically separable MnFe2O4–graphene photocatalysts with differing graphene content. It was found that graphene sheets were fully exfoliated and decorated with MnFe2O4 nanocrystals having an average diameter of 5.65 nm and a narrow particle size distribution. It is very interesting that, although MnFe2O4 alone is photocatalytically inactive under visible light irradiation, the combination of MnFe2O4 nanoparticles with graphene sheets leads to high photocatalytic activity for the degradation of methylene blue under visible light irradiation. The strong magnetic property of MnFe2O4 nanoparticles can be used for magnetic separation in a suspension system, and therefore it does not require additional magnetic components as is the usual case. Consequently, the MnFe2O4–graphene system becomes a dual function photocatalyst. The significant enhancement in photoactivity under visible light irradiation can be ascribed to the reduction of graphene o...
TL;DR: In this article, a 5-(hydroxymethyl)furfural (EMF) was produced from glucose in ethanol in a single reactor at 90 °C, where the reaction proceeds via the isomerization of glucose to fructose with zeolite Sn-Beta, a Lewis acid catalyst.
Abstract: 5-(Ethoxymethyl)furfural (EMF) was produced from glucose in ethanol in a single reactor at 90 °C. The reaction proceeds via the isomerization of glucose to fructose with zeolite Sn-Beta, a Lewis acid catalyst. Fructose is converted to 5-(hydroxymethyl)furfural, which is then etherified to EMF using a Bronsted acid catalyst, Amberlyst 131. An EMF yield of 31% was achieved.
TL;DR: In this article, the density, speed of sound, refractive index, and viscosity of the commercial ionic liquids 1-ethyl-3-methylpyridinium bis(trifluoromethylsulfonyl)imide, [EMim][NTf2] were measured as a function of temperature at atmospheric pressure.
Abstract: Density, speed of sound, refractive index, and viscosity of the commercial ionic liquids 1-ethyl-3-methylpyridinium bis(trifluoromethylsulfonyl)imide, [EMpy][NTf2], 1-propyl-3-methylpyridinium bis(trifluoromethylsulfonyl)imide, [PMpy][NTf2], 1-butyl-3-methylpyridinium bis(trifluoromethylsulfonyl)imide, [BMpy][NTf2], 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [EMim][NTf2], 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [HMim][NTf2], 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide, [BMpyr][NTf2], 1-butyl-1-methylpyrrolidinium trifluoromethanesulfonate, [BMpyr][TFO], 1-butyl-3-methylimidazolium trifluoromethanesulfonate, [BMim][TFO], 1-hexyl-3-methylimidazolium trifluoromethanesulfonate, [HMim][TFO], 1-butyl-3-methylimidazolium dicyanamide, [BMim][N(CN)2], and 1-hexyl-3-methylimidazolium dicyanamide, [HMim][N(CN)2] were measured as a function of temperature at atmospheric pressure. The density, speed of sound, and refractive index data were properly fitted ...
TL;DR: In this paper, the corrosion inhibition of mild steel in 1.0 M HCl solution by some selected imidazolium-based ionic liquids was investigated using weight loss, electrochemical measurements, and quantum chemical calculations.
Abstract: The corrosion inhibition of mild steel in 1.0 M HCl solution by some selected imidazolium-based ionic liquids, namely 1-propyl-3-methylimidazolium bis(trifluoromethyl-sulfonyl) imide ([PMIM][NTf2), 1-butyl-3-methylimidazolium bis(trifluoromethyl-sulfonyl) imide ([BMIM][NTf2), 1-hexyl-3-methylimidazolium bis(trifluoromethyl-sulfonyl) imide ([HMIM][NTf2]), and 1-propyl-2,3-methylimidazolium bis(trifluoromethyl-sulfonyl) imide ([PDMIM][NTf2]) was investigated using weight loss, electrochemical measurements, and quantum chemical calculations. All ionic liquids showed appreciable inhibition efficiency. Among the ionic liquids studied, [PDMIM][NTf2] exhibited the best inhibition efficiency. The results from the weight loss, electrochemical measurements and quantum chemical calculations show that the order of inhibition efficiency by the ionic liquids follow the order [PDMIM][NTf2] > [HMIM][NTf2] > [BMIM][NTf2] > [PMIM][NTf2]. At 303 K, polarization measurements indicated that all the studied compounds are mixed...