Showing papers in "Industrial & Engineering Chemistry Research in 2013"
TL;DR: In this paper, the authors summarized recent research dealing with development of titanium dioxide (TiO2) used for environmental applications and suggested new research directions, including preparation aspects for the development of this promising material.
Abstract: This paper summarizes recent research dealing with development of titanium dioxide (TiO2) used for environmental applications. TiO2 plays the most important role owing to its excellent chemical and physical properties. However, the TiO2 band edge lies in the UV region that makes them inactive under visible irradiation. In this regard, considerable efforts have been made to increase the visible light activity of TiO2 via the modification of its electronic and optical properties. Doping TiO2 using either anions or cations is one of the typical approaches that has been largely applied. Coupling TiO2 with a narrow bad gap semiconductor (MxOy/TiO2 or MxSy/TiO2) represents another approach. This work aims to encompass the new progress of TiO2 for an efficient application in water and wastewater treatment under visible light, emphasizes the future trends of TiO2 in the environment, and suggests new research directions, including preparation aspects for the development of this promising material.
1,281 citations
TL;DR: The natures of different industrial processes are revealed with their data characteristics analyzed and a corresponding problem is defined and illustrated, with review conducted with detailed discussions on connection and comparison of different monitoring methods.
Abstract: Data-based process monitoring has become a key technology in process industries for safety, quality, and operation efficiency enhancement. This paper provides a timely update review on this topic. First, the natures of different industrial processes are revealed with their data characteristics analyzed. Second, detailed terminologies of the data-based process monitoring method are illustrated. Third, based on each of the main data characteristics that exhibits in the process, a corresponding problem is defined and illustrated, with review conducted with detailed discussions on connection and comparison of different monitoring methods. Finally, the relevant research perspectives and several promising issues are highlighted for future work.
788 citations
TL;DR: In this article, a simple and facile one-pot synthesis of fluorescent carbon dots from orange waste peels was performed using the hydrothermal carbonization method at a mild temperature (180 °C).
Abstract: A simple and facile one-pot synthesis of fluorescent carbon dots from orange waste peels was performed using the hydrothermal carbonization method at a mild temperature (180 °C). The chemical composition and morphological feature of the obtained carbon dots (C-dots) were characterized using various spectroscopies and a transmission electron microscopy. The prepared hydrothermal carbons were amorphous in nature, and clusters of polyaromatic hydrocarbons included a large quantity of oxygen functional groups. A composite of C-dot with ZnO was used as a photocatalyst for degradation of naphthol blue-black azo dye under UV irradiation, and the superior photocatalytic activity was demonstrated. Overall, the present preparation method of C-dots takes on meaning in the area of green synthesis in aqueous solutions, and the product has great potential as a component material in the development of a remarkably efficient catalytic system.
376 citations
TL;DR: In this article, the authors investigated CO2 capture with 24 tertiary amine absorbents, including three synthetic amines, with systematic modification of their chemical structures, and compared them with the conventional tertiary absorbent N-methyldiethanolamine.
Abstract: In the present paper, we investigated CO2 capture with 24 tertiary amine absorbents, including three synthetic amines, with systematic modification of their chemical structures. Aqueous solutions of the amines (mass fraction 30%) were used to evaluate the performance for CO2 capture. Gas scrubbing, vapor–liquid equilibrium (VLE), and reaction calorimetry experiments were conducted in the laboratory to obtain the absorption rate, the amount of CO2 absorbed, cyclic CO2 capacity, and heat of reaction for each absorbent. The results for these absorbents were compared with the conventional tertiary absorbent N-methyldiethanolamine (MDEA). Seven of the investigated absorbents performed well with high absorption rates and cyclic capacities. Among these absorbents, some showed lower heats of reaction than MDEA. These results provide basic guidelines for discovery of potential tertiary amine-based absorbents that may lead to development of new absorbent systems in the CO2 capture area.
360 citations
TL;DR: In this article, an in situ microwave-assisted synthesis approach has been developed to prepare N-TiO2/g-C3N4 composites using H2TiO3 as the reactant and NH3·H2O as the N-doping source.
Abstract: An in situ microwave-assisted synthesis approach has been developed to prepare N-TiO2/g-C3N4 composites using H2TiO3 as the reactant and NH3·H2O as the N-doping source. In this way, the N-TiO2/g-C3N4 composite catalysts have a porous structure and large surface areas, which increase the contact area of pollutants. Degradation of rhodamine B (Rh B) and methylene blue (MB) were carried out to evaluate the photocatalytic activity of samples under visible light irradiation. N-TiO2/g-C3N4 composite with 40 wt % N-TiO2 exhibits the highest photocatalytic activity and the optimal temperature is 400 °C. The increased photocatalytic activity of N-TiO2/g-C3N4 composites can be attributed to the formation of the heterojunction between N-TiO2 and g-C3N4, which suppresses the recombination of photoinduced electron–hole pairs. The tests of radical scavengers confirmed that •O2– was the main reactive species during the photocatalytic process.
338 citations
TL;DR: An up-to-date review of the literature available on the subject of ethanol to ethylene can be found in this paper, where the authors present an overview of the current state-of-the-art in this area.
Abstract: This article is an up-to-date review of the literature available on the subject of ethanol to ethylene. The process of ethanol to ethylene has broad development prospects. Compared with the process of petroleum to ethylene, ethanol dehydration to ethylene is economically feasible. Researchers have been redirecting their interest to the ethylene production process, catalysts, and reaction mechanisms. A fluidized bed reactor, together with a wear-resistant, efficient, and stable catalyst will be the focus of future research that includes a deep understanding of the large-scale activated alumina catalyst and the molecular sieve catalyst used, and will promote the development of the ethanol dehydration to ethylene process and provide strong support for the market competiveness of the process.
337 citations
TL;DR: Ion exchange membranes play an important role today in deionization of aqueous solutions, in electrochemical synthesis, and in energy conversion and storage as discussed by the authors, and their advantages and limitations are discussed and their commercial relevance is indicated.
Abstract: Ion-exchange membranes play an important role today in deionization of aqueous solutions, in electrochemical synthesis, and in energy conversion and storage. Some of the applications of ion-exchange membranes are mature and well established processes such as the water desalination by electrodialysis or the electrolytic chlorine–alkaline synthesis. Other applications of ion-exchange membranes are still in an early state of their development, such as the redox flow battery. In this publication the principles of state-of-the-art ion-exchange membrane processes and their applications are briefly described. Their advantages and limitations are discussed, and their commercial relevance is indicated. More recently developed products and processes are also addressed. Their basic functions are described, and their present and potential future applications are discussed. Research needs for a further improvement of ion-exchange membranes and their applications are pointed out.
291 citations
TL;DR: In this article, the potential of ultrasound as a pretreatment and fractionation method of lignocellulose was evaluated and the challenges that this technology faces were identified, and the current status-quo of knowledge of the parametric effects of ultrasound was identified.
Abstract: The conversion of lignocellulosic biomass for biofuels and biorefinery applications is limited due to the cost of pretreatment to separate or access the biomass’s three main usable components, cellulose, hemicellulose, and lignin. After pretreatment, each component may be utilized via chemical conversion, hydrolysis, and/or fermentation. In this review we aim first, to identify the current status-quo of knowledge of the parametric effects of ultrasound, second, to evaluate the potential of ultrasound as a pretreatment and fractionation method of lignocellulose, and last, to identify the challenges that this technology faces. Ultrasound produces chemical and physical effects which were both found to augment the pretreatment of lignocellulose via delignification and surface erosion. The magnitudes of these effects are altered when the ultrasonic field is influenced by parameters such as solvent, ultrasonic frequency, and reactor geometry and type. Therefore, the implementation of ultrasound for the pretreat...
273 citations
TL;DR: In this paper, a green, ultralight, and highly porous material was successfully prepared from paper waste cellulose fibers, functionalized with methyltrimethoxysilane (MTMS) to enhance its hydrophobicity and oleophilicity.
Abstract: Polyprolylene is commonly used for crude oil spill cleaning, but it has low absorption capacity and is nonbiodegradable. In our work, a green, ultralight, and highly porous material was successfully prepared from paper waste cellulose fibers. The material was functionalized with methyltrimethoxysilane (MTMS) to enhance its hydrophobicity and oleophilicity. Water contact angles of 143 and 145° were obtained for the MTMS-coated recycled cellulose aerogel. The aerogel achieved high absorption capacities of 18.4, 18.5, and 20.5 g/g for three different crude oils at 25 °C, respectively. In the investigated temperature range of 10, 25, 40, and 60 °C for the absorption of the tested crude oil on the aerogel, a highest absorption capacity of 24.4 g/g was obtained. It was found that the viscosity of the crude oils is the main factor affecting their absorption onto the aerogel. The strong affinity of the MTMS-coated recycled cellulose aerogel to the oils makes the aerogel a good absorbent for crude oil spill cleaning.
273 citations
TL;DR: In this paper, the authors used the Langmuir and Freundlich adsorption models to describe the equilibrium isotherm and to calculate the equilibrium constants of FACs.
Abstract: Activated carbon derived from finger citron residue (FAC) was tested as a new type of adsorbent for the removal of harmful dyes, namely, the anionic dye methyl orange (MO) and the cationic dye methylene blue (MB), from contaminated water. Liquid-phase adsorption experiments were conducted, and the maximum adsorption capacity was determined. Various conditions were evaluated, including initial dye concentration, adsorbent dosage, contact time, solution pH, and temperature. The Langmuir and Freundlich adsorption models were used to describe the equilibrium isotherm and to calculate the isotherm constants. It was found that the adsorption capacity of FAC is much higher than those of other types of activated carbons. Maximum equilibrium adsorption capacities of 934.58 and 581.40 mg/g for MO and MB, respectively, were achieved. Three simplified kinetic models, namely, pseudo-first-order, pseudo-second-order, and intraparticle diffusion equations, were used to investigate the adsorption process. The pseudo-seco...
263 citations
TL;DR: In this paper, the classical theory of fibrous filters is described with focus on the principles that are applicable to nanoparticle collection and the areas of recent developments reviewed include thermal rebound of nanoparticles and the effects of particle shape, aggregate morphology, flow regime, humidity, fiber size, and particle loading.
Abstract: Although the basic principles of fibrous filters have been well understood for capture of micron and submicron sized particles, questions arise when they are applied to nanoscale particles. In the first part of this review, the classical theory of fibrous filters is described with focus on the principles that are applicable to nanoparticle collection. The areas of recent developments reviewed include thermal rebound of nanoparticles and the effects of particle shape, aggregate morphology, flow regime, humidity, fiber size, and particle loading. One of the outstanding questions in nanoparticle collection is the particle size at which the effect of thermal rebound on collection efficiency can be observed. Theoretical calculations indicate that the effect probably can be observed only for particles smaller than 1 nm, but experimental confirmation is difficult at present because of lack of instruments for classifying and counting subnanoscale particles. Two promising devices based on filtration principles hav...
TL;DR: This critical review highlights the design and the applications of sensitive and selective ratiometric nanoprobes based on FRET and focuses on the benefits and limitations of nano-FRET systems and their applications as chemical sensors and biosensors.
Abstract: Fluorescence resonance energy transfer (FRET) has been widely used as a spectroscopic technique in various areas such as structural elucidation of biological molecules and their interactions, in vitro assays, in vivo monitoring in cellular research, nucleic acid analysis, signal transduction, light harvesting, and metallic nanomaterials. Meanwhile, based on the mechanism of FRET, a series of FRET nanomaterials systems have been recently developed as novel chemical sensors and biosensors. Compared with those based on small molecules traditional FRET systems, the surface chemistry of nanomaterial has encouraged the development of multiple probes based on linked recognition molecules such as peptides, nucleic acids, or small-molecule ligands. This critical review highlights the design and the applications of sensitive and selective ratiometric nanoprobes based on FRET. We focus on the benefits and limitations of nano-FRET systems and their applications as chemical sensors and biosensors.
TL;DR: In this article, the authors review the role of different biopolymers in the development of antimicrobial textiles and present some of the attributes that make chitosan, cyclodextrin, sericin protein, and alginate suitable alternative agents for the functional finishing of textile materials.
Abstract: In recent years, the population explosion and environmental pollution have increased the interest of researchers in the discovery of new health and hygiene-related products for the well being of mankind. Among the possible approaches initiated by the textile industry, the use of low-environmental impact technologies- based on sustainable biopolymers- presents a novel possible avenue for large scale development of bioactive textiles. The purpose of this article is to review the information on the role of different biopolymers in the development of antimicrobial textiles. Increased sustainability, environment friendliness, reduced pollution, green chemistry, renewability and intrinsic biological activity are some of the attributes which make chitosan, cyclodextrin, sericin protein, and alginate suitable alternative agents for the functional finishing of textile materials. The application of biopolymers, along with the recent impact of various “green chemistry” strategies, on the antimicrobial properties of ...
TL;DR: In this article, more complex refrigeration cycle designs that combine two or more different conventional single refrigeration cycles are being developed to obtain synergistic effects in the liquefaction process, which is expected that this trend in the use of LNG will lead to steady increases in demand over the next few decades.
Abstract: Liquefied natural gas (LNG) is attracting great interest as a clean energy alternative to other fossil fuels, mainly due to its ease of transport and low carbon dioxide emissions, a primary factor in air pollution and global warming. It is expected that this trend in the use of LNG will lead to steady increases in demand over the next few decades. To meet the growing demand for LNG, natural gas liquefaction plants have been constructed across the globe. Furthermore, single train capacity has been increased to strengthen price competitiveness. To achieve greater capacity, more complex refrigeration cycle designs that combine two or more different conventional single refrigeration cycles are being developed to obtain synergistic effects in the liquefaction process. At the same time, a variety of recent studies have focused on designing suitable processes for offshore and small-scale plants to improve the profitability of stranded gas fields. LNG plants are known to be energy/cost-intensive, as they require ...
TL;DR: In this paper, the solubility of carvedilol in ethanol and propylene glycol mixtures at various temperatures was investigated and the results showed that carvedilols are solubile in both types of mixtures.
Abstract: Article on the solubility of carvedilol in ethanol and propylene glycol mixtures at various temperatures.
TL;DR: This paper intends to develop a new sub-block principal component analysis (PCA) method for plant-wide process monitoring, which is named as distributed PCA model, and both of the monitoring and fault diagnosis schemes are developed based on the distributedPCA model.
Abstract: For plant-wide process monitoring, most traditional multiblock methods are under the assumption that some process knowledge should be incorporated for dividing the process into several sub-blocks. ...
TL;DR: In this paper, three benzimidazole derivatives were synthesized and investigated as inhibitors for mild steel corrosion in 15% HCl solution using the weight loss, electrochemical polarization and electrochemical impedance spectroscopy (EIS) techniques.
Abstract: In the present investigation, three benzimidazole derivatives, namely, 4-(phenyl)-5-[(2-methyl-1H-benzimidazol-1-yl)methyl]-4H-1,2,4-triazole-3-thiol (Inh I), 4-(4-methylphenyl)-5-[(2-methyl-1H-benzimidazol-1-yl)methyl]-4H-1,2,4-triazole-3-thiol (Inh II), and 4-(4-methoxyphenyl)-5-[(2-methyl-1H-benzimidazol-1-yl)methyl]-4H-1,2,4-triazole-3-thiol (Inh III), were synthesized and investigated as inhibitors for mild steel corrosion in 15% HCl solution using the weight loss, electrochemical polarization, and electrochemical impedance spectroscopy (EIS) techniques. It was found that the inhibition efficiency of these inhibitors increased with increasing concentration. The effect of temperature on the corrosion rate was investigated, and some thermodynamic parameters were calculated. Polarization studies showed that all three studied inhibitors were of mixed type in nature. The adsorption of the inhibitors on the mild steel surface in acid solution was found to obey the Langmuir adsorption isotherm. Scanning ele...
TL;DR: In this paper, a simple vapor phase deposition process was developed to fabricate a super-hydrophobic and super-oleophilic sponge using ordinary commercial polyurethane sponges.
Abstract: A simple vapor-phase deposition process has been developed to fabricate a superhydrophobic and superoleophilic sponge using ordinary commercial polyurethane sponges. The simultaneous properties of superhydrophobicity and superoleophilicity enable the sponge to float on the water surface and selectively absorb oil from water. Its uptake capacities of different oils (motor oil, lubricating oil, pump oil, silicone oil, and soybean oil) in the oil–water mixtures were all above 20 g/g. The absorbed oil could be collected by squeezing the sponge, and the recovered sponge could be reused in oil–water separation for many cycles while still maintaining a high capacity. This is helpful for realizing the proper disposal of the oil and avoiding secondary pollution. A similar experiment was performed using the as-prepared sponge to remove petroleum from contaminated water. The results suggest that our material might find practical applications in the cleanup of oil spills and the removal of organic pollutants from wat...
TL;DR: In this article, the inhibitive action of ethanol extract of Acalypha torta leaves (EAL) on corrosion of mild steel in 1 M HCl solution was investigated by weight loss, potentiodynamic polarization, electrochemical impedance spectroscopy, chronoamperometric measurements, and scanning electron microscopic observations.
Abstract: The inhibitive action of ethanol extract of Acalypha torta leaves (EAL) on corrosion of mild steel in 1 M HCl solution was investigated by weight loss, potentiodynamic polarization, electrochemical impedance spectroscopy, chronoamperometric measurements, and scanning electron microscopic observations. The adsorption of EAL on mild steel follows a Langmuir adsorption isotherm, and the activation parameters governing the adsorption process were calculated and discussed. Polarization measurements reveal that the EAL acts as a mixed-type inhibitor. The inhibition efficiencies obtained from weight loss measurements and electrochemical tests were in good agreement.
TL;DR: In this paper, a robust and efficient finite volume based ad-sorption process simulator was developed for rigorous optimization of a transient cyclic operation without resorting to any model reduction.
Abstract: In this study, we first report the development of a robust and efficient finite volume based adsorption process simulator, essential for rigorous optimization of a transient cyclic operation without resorting to any model reduction. We present a detailed algorithm for the common boundary conditions encountered in nonisothermal and nonisobaric adsorption process simulations. A comprehensive comparison of the high-resolution total variation diminishing (TVD) schemes, namely, van Leer and Superbee, with the weighted essentially nonoscillatory (WENO) finite volume scheme is performed, and trade-off plots are presented to identify the numerical scheme most suitable for attaining speed and accuracy at the same time. The simulator is then used to perform rigorous optimization of a four-step process for postcombustion CO2 capture from dry flue gas on zeolite 13X. The aim is to identify operating conditions at which the purity and recovery demands are met and to calculate corresponding energy consumption and proce...
TL;DR: In this article, the state of the art of the scientific knowledge and technical aspects related to propene oxide synthesis in the presence of TS-1 catalyst have been reviewed and compared.
Abstract: Propene oxide is a very important chemical whose production technology has changed a lot during the last 30 years. Nowadays, the most promising technology is the HPPO process in which the propene oxide is produced by oxidizing propene with hydrogen peroxide, via titanium silicalite-1 (TS-1) catalysis. Even if this technology has been patented in the early 1980s and some chemical plants are already in production, only few papers have been published until now dealing with the catalytic and kinetic aspects of the process. In this paper, the state of the art of the scientific knowledge and technical aspects related to propene oxide synthesis in the presence of TS-1 catalyst have been reviewed.
TL;DR: In this article, a cross-linked ZIF/polymer MMM was used for gas separation in 6FDA-durene at 35 °C and 3.5 atm.
Abstract: The demand for cost-efficient separations requires membranes with high gas flux and high selectivity which opens the path for further improvements. Mixed matrix membranes (MMMs) made from 33.3 wt % ZIF-8 in 6FDA-durene were tested at 35 °C and 3.5 atm. At 33.3 wt % loading of ZIF-8, H2, N2, O2, and CH4 gas permeabilities increased approximately 400%. Cross-linking the surface of this MMM, by reacting with ethylenediamine vapor, yielded a 10-fold increase in H2/CO2, H2/N2, and H2/CH4 selectivities with respect to 6FDA-durene, preserving 55% of the H2 permeability of 6FDA-durene. The permselective properties of the cross-linked skin of the MMM fall above the most recent permeability–selectivity trade-off lines (2008 Robeson upper bounds) for H2/CO2, H2/N2, and H2/CH4 separations. To the best of our knowledge, this is the first example of a cross-linked ZIF/polymer MMM for gas separation.
TL;DR: In this article, the surface morphology and structure of the Mn3O4-reduced graphene oxide (rGO) hybrid were characterized by field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscope (TEM), powder Xray diffraction (XRD), Raman spectroscope, XPS, and thermogravimetric analysis.
Abstract: Mn3O4–reduced graphene oxide (rGO) hybrids were synthesized, and their catalytic performance in heterogeneous activation of peroxymonosulfate (PMS) to oxidize a target pollutant, Orange II, in aqueous solutions was investigated. The surface morphology and structure of the Mn3O4–rGO hybrids were characterized by field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), powder X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA). Through an in situ chemical deposition and reduction, Mn3O4–rGO hybrids with Mn3O4 nanoparticles at an average size of 29.2 nm were produced. The catalytic activity in Orange II oxidative decomposition was evaluated in view of the effects of various processes, pH, PMS concentration, Orange II concentration, and temperature. The combination of Mn3O4 nanoparticles with graphene sheets leads to a much higher catalytic activity than that of...
TL;DR: In this article, two main routes have been proposed, considering many studies at laboratory scale and others from industry: catalytic hydrotreatment (HDT), mainly hydrodeoxygenation (HDO), and catalytic cracking, technologies that are already present in today's refineries configuration.
Abstract: The envisaged upgrading of lignocellulosic biomass derived feedstocks (bio-oils) in dedicated units or by coprocessing in existing units of the refinery, to partially replace crude oil in the production of transportation fuels, is a topic that has been receiving much attention from both industry and academia in recent years. Regardless of lignocellulosic biomass origin, these feedstocks are complex mixtures of many oxygenated hydrocarbons. Therefore, their upgrading toward liquid fuels must include oxygen removal. So far, two main routes have been proposed, considering many studies at laboratory scale and others from industry: catalytic hydrotreatment (HDT), mainly hydrodeoxygenation (HDO), and catalytic cracking, technologies that are already present in today’s refineries configuration. HDO has been performed at high hydrogen pressure, using catalysts based on those typically applied in conventional hydrotreating, as well as a new type of supported noble metal and transition metal catalysts. Catalytic cr...
TL;DR: In this article, the methanation of CO and CO2 present in coke oven gas was performed in a fixed-bed catalytic reactor at a reaction temperature between 200 and 400 °C.
Abstract: The methanation of CO and CO2 present in coke oven gas was performed in a fixed-bed catalytic reactor at a reaction temperature between 200 and 400 °C. Different support materials, including SiO2, ...
TL;DR: In this article, a well-crystallized layered two-dimensional bismuth oxyhalide (BiOX; X = Cl, Br, I) single-crystal nanoplates were synthesized via a facile and low-cost method at room temperature.
Abstract: Well-crystallized layered two-dimensional bismuth oxyhalide (BiOX; X = Cl, Br, I) single-crystal nanoplates were synthesized via a facile and low-cost method at room temperature. The as-synthesized samples were analyzed by various characterization techniques. The photocatalytic activity of the samples was evaluated by the removal of NO at the indoor air level under visible-light irradiation. The band gap and thermal stability of bismuth oxyhalides decreased with increased X atomic numbers. The as-synthesized BiOBr nanoplates exhibited highest photocatalytic activity due to the favorable factors of ultrathin nanoplates, layered structures, relatively high surface area, and suitable band structure, exceeding that of BiOCl and BiOI. The present work could provide new insight into the low-temperature preparation and appropriate selection of visible-light photocatalysts for environmental application.
TL;DR: In this paper, the performance of ionic liquids (ILs) as alternative solvents in the liquid-liquid extraction of toluene from heptane was evaluated at 313.2 K.
Abstract: The performance of the 1-ethyl-3-methylimidazolium dicyanamide ([emim][DCA]), 1-butyl-3-methylimidazolium dicyanamide ([bmim][DCA]), and 1-ethyl-3-methylimidazolium tricyanomethanide ([emim][TCM]) ionic liquids (ILs) as alternative solvents in the liquid–liquid extraction of toluene from heptane was evaluated at 313.2 K. These ILs were selected due to their low viscosity and their highly aromatic character. Densities and viscosities of the ILs have also been determined over the temperature range from 293.15 to 353.15 K. To analyze the potential of the ILs to be applied in an industrial aromatic extraction process, toluene and heptane distribution ratios, separation factors, and physical properties of the ILs have been compared to the sulfolane values. In addition, the nonrandom two-liquid model successfully correlated the liquid–liquid equilibrium data for the three ternary systems studied.
TL;DR: In this article, a method was applied to treat a selection of hazardous organic compounds using nanoscale zerovalent iron (nZVI) particles as activators for persulfate.
Abstract: Recently, persulfate has caught the attention of groundwater remediation practitioners as a promising oxidant for in situ chemical oxidation. In this study, a method was applied to treat a selection of hazardous organic compounds using nanoscale zerovalent iron (nZVI) particles as activators for persulfate. The results show that degradation of these organic compounds using nZVI-activated persulfate is more effective than nZVI alone. For example, the degradation of naphthalene by nZVI-activated persulfate was >99% compared to <10% by nZVI alone. Despite the higher effectiveness, the nZVI particles were passivated quickly following exposure to persulfate, causing the reaction rate to reduce to a magnitude representative of an unactivated persulfate system. X-ray photoelectron spectroscopy analyses indicated that an iron sulfate layer was formed on the nZVI particle surfaces following exposure to persulfate compared to the FeOOH layer that was present on the fresh nZVI surfaces. Although the nZVI particle su...
TL;DR: In this article, the performance of thin MOF-5 membranes for high quality, thin (∼14 μm) MOF5 membranes prepared by the secondary growth method were studied at different temperatures, feed pressures, and feed composition.
Abstract: Permeation and separation properties of CO2/H2 and CO2/N2 mixtures for high quality, thin (∼14 μm) MOF-5 membranes prepared by the secondary growth method were studied at different temperatures, feed pressures, and feed composition. The MOF-5 membranes offer selective permeation for CO2 over H2 or N2 with CO2/H2 or CO2/N2 mixture feed under the experimental conditions studied. Compared to pure gas permeance data, the presence of the strongly adsorbing CO2 in the binary mixture separation suppresses less adsorbing H2 or N2, similar to what was observed for zeolite membranes. The MOF-5 membranes exhibit a separation factor for CO2/H2 of close to 5 with a feed CO2 composition of 82% and a separation factor for CO2/N2 greater than 60 with a feed CO2 composition of 88% at 445 kPa and 298 K. With the mixture feed, CO2 permeance increases and N2 (or H2) permeance decreases, and hence the CO2/N2 (or H2) separation factor increases, with increasing CO2 partial pressure (through the change of composition or feed pr...
TL;DR: A new magnetic mesoporous carbon composite (Fe3O4/C) was synthesized and characterized by XRD, nitrogen adsorption-desorption isotherms, FT-IR, TG, ζ potential, SEM, and TEM as mentioned in this paper.
Abstract: A new magnetic mesoporous carbon composite (Fe3O4/C) was synthesized and characterized by XRD, nitrogen adsorption–desorption isotherms, FT-IR, TG, ζ potential, SEM, and TEM. The performance of usi...