Showing papers in "Industrial & Engineering Chemistry Research in 2015"

A Novel DNA Biosensor Based on a Pencil Graphite Electrode Modified with Polypyrrole/Functionalized Multiwalled Carbon Nanotubes for Determination of 6-Mercaptopurine Anticancer Drug

Abstract: A novel and sensitive biosensor employing immobilized DNA on a pencil graphite electrode modified with polypyrrole/functionalized multiwalled carbon nanotubes for the determination of 6-mercaptopurine (6-MP) is presented. In the first step, we modified the pencil graphite surface with polypyrrole and functionalized multiwalled carbon nanotubes (MWCNT/COOH). The developed electrode was characterized by scanning electron microscopy, atomic force microscopy, reflection–absorption infrared spectroscopy, X-ray photoelectron spectroscopy, and electrochemical impedance spectroscopy. In the other step, we used decreases in the oxidation responses of guanine and adenine as a sign of the interaction of 6-MP with salmon sperm double-stranded DNA using differential pulse voltammetry. The signal of guanine oxidation was linear with respect to the 6-MP concentration in the range of 0.2–100 μmol L–1 with a detection limit of 0.08 μmol L–1. The modified electrode was utilized for the determination of 6-MP in real samples.

Role of Surfactants in Promoting Gas Hydrate Formation

Abstract: Gas hydrates have been proposed as a potential technology for a number of applications, such as separation of gas mixtures, CO2 capture, transportation, and sequestration, methane storage and transport, and seawater desalination. Most of these applications will benefit from reduced induction time of hydrate nucleation, enhanced hydrate growth rate, and maximum water-to-hydrate conversion. The addition of surfactants to the gas–water system serves this purpose in a very effective manner. This review focuses on different surfactants that were utilized for gas hydrate formation studies; insights have been provided on the possible mechanisms of action through which these surfactants affect hydrate formation kinetics. A thorough analysis of the existing literature on surfactants suggests that enhanced rate of hydrate nucleation and growth kinetics may not be directly linked to micelle formation. Conversely, reduced surface tension in the presence of surfactants not only enhances the mass transfer but also chan...

Model for Surface Diffusion of Adsorbed Gas in Nanopores of Shale Gas Reservoirs

Abstract: Surface diffusion plays a key role in gas mass transfer due to the majority of adsorbed gas within abundant nanopores of organic matter in shale gas reservoirs Surface diffusion simulation is very complex as a result of high reservoir pressure, surface heterogeneity, and nonisothermal desorption in shale gas reservoirs In this paper, a new model of surface diffusion for adsorbed gas in shale gas reservoirs is established, which is based on a Hwang model derived under a low pressure condition and considers the effect of adsorbed gas coverage under high pressure Additionally, this new model considers the effects of surface heterogeneity, isosteric sorption heat, and nonisothermal gas desorption Results show that (1) the surface diffusion coefficient increases with pressure and temperature, while it decreases with activation energy and gas molecular weight; (2) contributions of viscous flow, Knudsen diffusion, and surface diffusion to the total gas mass transfer are varying during the development of shal

Critical Review on the Toxicity of Some Widely Used Engineered Nanoparticles

Abstract: With tremendous increase in development of nanotechnology, there is a developing enthusiasm toward the application of nanoparticles in diverse areas. Carbon nanotubes, fullerenes, quantum dots, dendrimers, iron oxide, silica, and gold and silver nanoparticles are frequently used in different applications such as drug delivery, ceramic materials, semiconductors, electronics, medicine, cosmetics, etc. Some of these nanoparticles have shown major toxic effects on fauna, flora, and human beings, such as inflammation, cytotoxicity, tissue ulceration, and reduction of cell viability. Single-walled carbon nanotubes (SWCNTs) and multiwalled carbon nanotubes (MWCNTs) can induce oxidative stress and fibrosis in the lungs of rat and mice. SWCNTs can also induce oxidative stress to the nervous system in human beings. Inflammatory injury and respiratory distress can be observed due to TiO2 nanoparticles with small diameter. Nanoparticles can also pose detrimental effects on plants, such as decreased growth rate, genom...

Additive Manufacturing Technologies Compared: Morphology of Deposits of Silver Ink Using Inkjet and Aerosol Jet Printing

Abstract: We report about a detailed comparison of the additive manufacturing methods inkjet printing (IJP) and aerosol jet printing (AJP). Both technologies are based on the direct-writing approach enabling the non-contact deposition of various materials in flexible patterns, e.g., for printed electronic applications. The deposited pattern elements were classified as (i) drops (IJP) or splats (AJP), (ii) lines, and (iii) squares. These elements can be considered as basic elements of the deposition systems and also of printed electronics. The pattern elements were deposited with IJP and AJP using the same silver nanoparticle ink. After printing, the layers were characterized regarding their morphology by optical and topographical measurement methods as well as regarding their electrical characteristics. It turned out that drops deposited with IJP and splats deposited with AJP can have similar dimensions. However, the shapes of the deposits differ widely. In the case of lines, AJP enables narrower line widths and th...

Liquid Organic Hydrogen Carriers: Thermophysical and Thermochemical Studies of Benzyl- and Dibenzyl-toluene Derivatives

Abstract: The heat transfer oils dibenzyltoluene and benzyltoluene are promising materials as a new class of liquid organic hydrogen carrier compounds (LOHC). Thermophysical properties (heat capacity, density, viscosity, and surface tension) of the commercially available thermofluids Marlothem LH (benzyltoluene) and Marlotherm SH (dibenzyltoluene) and their completely hydrogenated derivatives were measured. Thermochemical properties (enthalpies of combustion and enthalpies of vaporization) were derived from experiments. Gas-phase molar enthalpies of formation were derived and validated with group-additivity and high-level quantum chemical calculations. Enthalpies of the hydrogenation/dehydrogenation reactions of the LOHC pairs under study were derived.

Mussel-Inspired Green Metallization of Silver Nanoparticles on Cellulose Nanocrystals and Their Enhanced Catalytic Reduction of 4-Nitrophenol in the Presence of β-Cyclodextrin

Abstract: A green approach to anchor silver nanoparticles (AgNPs) onto the surface of cellulose nanocrystals (CNCs) coated with mussel-inspired polydopamine (PDA) at room temperature in the absence of a stabilizer and a reducing agent is proposed. The resulting nanohybrids possessed a core–shell structure with numerous “satellites” of silver nanoparticles decorating the CNC surface. The nanocatalyst displayed superior dispersibility over pristine AgNPs and was six times more efficient in catalyzing the reduction of 4-nitrophenol. By associating the CNC hybrid with β-cyclodextrin to promote host–guest interactions, the catalytic process was accelerated. The associated physicochemical parameters associated with the catalytic process were investigated and compared.

Application of Steam Explosion as Pretreatment on Lignocellulosic Material: A Review

Abstract: Steam explosion is a thermo-mechanicochemical pretreatment which allows the breakdown of lignocellulosic structural components by the action of heating, formation of organic acids during the process, and shearing forces resulting in the expansion of the moisture. Two distinct stages compose the steam-explosion process: vapocracking and explosive decompression which include modification of the material components: hydrolysis of hemicellulosic components (mono- and oligosaccharides released), modification of the chemical structure of lignin, and modification of the cellulose crystallinity index, etc. These effects allow the opening of lignocellulosic structures and influence the enzymatic hydrolysis yield of the material.

Synthesis of a Phosphorus/Nitrogen-Containing Additive with Multifunctional Groups and Its Flame-Retardant Effect in Epoxy Resin

Abstract: A novel additive, tri(phosphaphenanthrene-maleimide-phenoxyl)-triazine (DOPO-TMT), was successfully synthesized. The chemical structure was characterized by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance. DOPO-TMT was blended with epoxy resins to prepare flame-retardant thermosets. The flame-retardant properties were evaluated using limited oxygen index (LOI), vertical burning (UL94), and cone calorimeter tests. The results indicated that DOPO-TMT exhibited excellent flame-retardant effect. The flame-retardant mechanism was studied by thermogravimeric analysis (TGA), pyrolysis-gas chromatography/mass spectrometry, and thermogravimetric analysis/infrared spectrometry (TGA-FTIR) coupled with the morphology and chemical analysis of the char residues. The results disclosed that DOPO-TMT exerted biphase flame-retardant effect. In gaseous-phase, DOPO-TMT released phosphorus- and nitrogen-containing free radicals with quenching effect under thermal decomposition. The morphologies o...

Novel Heat-Pump-Assisted Extractive Distillation for Bioethanol Purification

Abstract: The purification of bioethanol fuel involves an energy-intensive separation process to concentrate the diluted streams obtained in the fermentation stage and to overcome the azeotropic behavior of the ethanol-water mixture The conventional separation sequence employs three distillation columns that carry out several tasks, penalized by high-energy requirements: preconcentration of ethanol, extractive distillation, and solvent recovery To solve this problem, we propose here a novel heat-pump-assisted extractive distillation process taking place in a dividing-wall column (DWC) In this configuration, the ethanol top vapor stream of the extractive DWC is recompressed from atmospheric pressure to over 31 bar (thus to a higher temperature) and used to drive the side reboiler of the DWC, which is responsible for the water vaporization For a fair comparison with the previously reported studies, we consider here a mixture of 10 wt % ethanol (100 ktpy plant capacity) that is concentrated and dehydrated using ethylene glycol as mass-separating agent Rigorous process simulations of the proposed vapor recompression (VRC) heat-pump-assisted extractive DWC were carried out in AspenTech Aspen Plus The results show that the specific energy requirements drop from 207 kWh/kg (classic sequence) to only 124 kWh/kg ethanol (VRC-assisted extractive DWC); thus, energy savings of over 40% are possible Considering the requirements for a compressor and use of electricity in the case of the heat-pump-assisted alternative, it is possible to reduce the total annual cost by approximately 24%, despite the 29% increase of the capital expenditures, for the novel process as compared to the optimized conventional separation process

High Throughput Screening and Selection Methods for Directed Enzyme Evolution.

Abstract: Successful evolutionary enzyme engineering requires a high throughput screening or selection method, which considerably increases the chance of obtaining desired properties and reduces the time and cost. In this review, a series of high throughput screening and selection methods are illustrated with significant and recent examples. These high throughput strategies are also discussed with an emphasis on compatibility with phenotypic analysis during directed enzyme evolution. Lastly, certain limitations of current methods, as well as future developments, are briefly summarized.

Density Functional Theory-Assisted Microkinetic Analysis of Methane Dry Reforming on Ni Catalyst

Abstract: A comprehensive microkinetic model based on density functional theory (DFT) calculations is constructed to explore the reaction mechanism for dry methane reforming on Ni catalyst. Three low-index facets, namely, Ni(111), Ni(100), and Ni(211), are utilized to represent the contributions from the flat, open, and stepped surfaces. Adsorption energies of all the possible reaction intermediates as well as activation energies for the elementary reactions involved in dry reforming of methane on the three Ni surfaces are calculated through DFT. These results are further employed to estimate the rate constants for the elementary reactions under realistic temperatures and pressures within the framework of transition state theory and statistical mechanics treatments. The dominant reaction pathway is identified as CH4 successive dissociation followed by carbon oxidation by atomic oxygen. The dependence of the rate-determining step on operating conditions is examined. At low CH4 and CO2 partial pressures, both CH4 dis...

Tuning the Kinetic Water Stability and Adsorption Interactions of Mg-MOF-74 by Partial Substitution with Co or Ni

Abstract: Varying amounts of Co and Ni were substituted into the metal–organic framework Mg-MOF-74 via a one-pot solvothermal reaction, and the effects of these substitutions on CO2 adsorption and kinetic water stability properties were examined. Based on elemental analyses, Co and Ni are more favorably incorporated into the MOF-74 framework from solution than Mg. In addition, reaction temperature more strongly impacts the final metal composition in these mixed-metal (MM) MOF-74 structures than does the reaction solvent composition. Single-component CO2 adsorption isotherms were measured for the MM-MOF-74 systems at 5, 25, and 45 °C, and isosteric heats of adsorption were calculated. These results suggest that CO2 adsorption properties can be adjusted by partial metal substitution. Water adsorption isotherms were also measured for the MM-MOF-74 samples, with powder X-ray diffraction patterns and Brunauer–Emmett–Teller surface areas measured both before and after water exposure. Results show that Mg-MOF-74 can gain ...

Highly Hydrophobic, Compressible, and Magnetic Polystyrene/Fe3O4/Graphene Aerogel Composite for Oil–Water Separation

Abstract: A solvothermal technique to process novel graphene aerogel/Fe3O4/polystyrene composites with reticulated graphene structure is described. Porous Fe3O4 nanoparticles as a partial substitute for ethylenediamine assisted cross-linking and interconnections between graphene plates. Fe3O4 and polystyrene incorporation allowed a porous substructure to be formed on the reticulated graphene surfaces, effectively enhancing the hydrophobicity. The compressibility and directional recovery were achieved with the composite having an extremely low density of 0.005 g cm–3, corresponding to a volume porosity of 99.7%. The crude oil intake capacity for the composite was 40 times its own mass after 10 water–oil separation cycles, which is among the highest ever reported for oil absorbents. Furthermore, the incorporation of porous Fe3O4 nanoparticles enabled magnetism which, in combination with compressibility, allowed the oil-soaked graphene composite to be readily collected by a magnet and oil to be squeezed out before the...

Group Contribution Method for Viscosities Based on Entropy Scaling Using the Perturbed-Chain Polar Statistical Associating Fluid Theory

Abstract: In this work, we propose a new predictive entropy-scaling approach for Newtonian shear viscosities based on group contributions. The approach is based on Rosenfeld’s original work [Rosenfeld, Y. Phys. Rev. A 1977, 15, 2545−2549]. The entropy scaling is formulated as third order polynomial in terms of the residual entropy as calculated from a group-contribution perturbed-chain polar statistical associating fluid theory (PCP-SAFT) equation of state. In this study, we analyze the course of entropy scaling parameters within homologous series and suggest suitable mixing rules for the parameters of functional groups. The viscosity of nonpolar, of polar, and of self-associating (hydrogen bonding) components are considered. In total, 22 functional groups are parametrized to viscosity data of 110 pure substances, from 12 different chemical families. The mean absolute relative deviations (MADs) to experimental viscosity data are typically around 5%. For three chemical families, namely, branched alkanes, 1-alcohols,...

Green Synthesis of Magnetic EDTA- and/or DTPA-Cross-Linked Chitosan Adsorbents for Highly Efficient Removal of Metals

Abstract: The present paper describes a green and economic approach to explore EDTA/DTPA-functionalized magnetic chitosan as adsorbents for the removal of aqueous metal ions, such as Cd(II), Pb(II), Co(II), and Ni(II). EDTA and DTPA play roles not only as cross-linkers but also as functional groups in chelating metal ions. The morphology, structure, and property of the magnetic adsorbents were characterized by SEM, TEM, XRD, EDS, FT-IR, TGA, and VSM techniques. Their adsorption properties for the removal of metal ions by varying experimental conditions were also investigated. The kinetic results revealed that the transportation of adsorbates from the bulk phase to the exterior surface of adsorbents was the rate-controlling step. The obtained maximum adsorption capacities of magnetic adsorbents for the metal ions ranged from 0.878 to 1.561 mmol g–1. Bi-Langmuir and Sips isotherm models fitting well to the experimental data revealed the surface heterogeneity of the adsorbents. More significantly, the resulting EDTA-/...

Study of Nanoparticle–Surfactant-Stabilized Foam as a Fracturing Fluid

Abstract: The development of hydraulic fracturing has created a huge demand for fracturing fluids with high performance and low formation damage in recent years. In this paper, a foam stabilized by partially hydrophobic modified SiO2 nanoparticles and sodium dodecyl benzenesulfonate (SDBS) was studied as a fracturing fluid. The properties of SiO2/SDBS foam such as rheology, proppant suspension, filtration, and core damage were investigated. The experimental data showed that the stability and thermal adaptability of sodium dodecyl benzenesulfonate (SDBS) foam increased when silica (SiO2) nanoparticles were added. The surface tension of SDBS dispersion almost did not change after SiO2 nanoparticles were added; however, the dilational viscoelasticity of the interface increased, indicating that the SiO2 nanoparticles attached to the interface and formed a stronger viscoelasticity layer to resist the external disturbance. The proppant settling velocity in the SiO2/SDBS foam was found to be 2 orders of magnitude lower th...

Efficient SO2 Absorptions by Four Kinds of Deep Eutectic Solvents Based on Choline Chloride

Abstract: Four kinds of deep eutectic solvents (DESs) based on choline chloride (ChCl) with ethylene glycol (EG), malonic acid (MA), urea, and thiourea as hydrogen bond donors were prepared and characterized. All these DESs show good thermal stability and can be stable at 363 K, which is beneficial for the application in flue gas desulfurization. Then, SO2 absorption capacities of these DESs were determined at different temperatures and SO2 partial pressures. The absorption results demonstrate that ChCl–EG (1:2) and ChCl–thiourea (1:1) DESs exhibit excellent absorption performances, and the absorption capacities are 2.88 and 2.96 mol SO2 per mol DES at 293 K and 1 atm, respectively. In addition, the SO2 absorption and regeneration experiments were conducted. All solvents can be regenerated at 343 K with N2 bubbling, and the absorption capacities of DESs remain without a significant loss after six absorption and desorption cycles. What’s more, the absorption mechanism of SO2 in these DESs were investigated by IR and...

Graphene Hybridized Photoactive Iron Terephthalate with Enhanced Photocatalytic Activity for the Degradation of Rhodamine B under Visible Light

Abstract: In this study, we report the design and fabrication of a series of visible-light-responsive photocatalysts based on one-dimensional iron terephthalate (MIL-53(Fe)) microrods hybridized with graphene (GR) and experimentally demonstrate their remarkably improved visible-light-induced photocatalytic activity. During the solvothermal process, the reduction of graphene oxide (GO) is accompanied by the MIL-53(Fe) crystallization, which endows them with effective interfacial contact, thus facilitating the transfer of photogenerated charge to lower the recombination rate of excited carriers. The GR/MIL-53(Fe)-H2O2 systems exhibit significantly higher photocatalytic activity toward degrading Rhodamine B (RhB) than that of bare MIL-53(Fe)-H2O2 under visible light irradiation. The introduced H2O2 induces photosynergistic generation of more amounts of hydroxyl radicals to contribute to the improved photocatalytic activity. This work could open a new way for the exploration and utilization of metal–organic framework (...

Behavior of Asphaltene Adsorption onto the Metal Oxide Nanoparticle Surface and Its Effect on Heavy Oil Recovery

Abstract: Preventing asphaltene-related damage in hydrocarbon reservoirs is an important concern. Many investigations have been performed on asphaltene and its effects and how to reduce these effects during oil production. In the present work, some experiments were conducted to investigate the effects of SiO2, NiO, and Fe3O4 nanoparticles on oil recovery and to determine how they adsorb asphaltene and prevent its precipitation. Moreover, instead of crude oil, a synthetic solution with a given component concentration was used. The results of this study show that, in solutions without nanoparticles, an increase in the amount of n-heptane causes more asphaltene aggregation to take place; however, in the presence of nanoparticles, increasing the n-heptane content results in an increase in the asphaltene adsorption on the surface of nanoparticles. Furthermore, it is shown that the amount of oil recovery in the presence of different nanoparticles corresponds to the ordering SiO2 > NiO > Fe3O4.

Hydrothermal Reactions of Biomolecules Relevant for Microalgae Liquefaction

Abstract: Hydrothermal liquefaction (HTL) of microalgae, a process that uses water at high temperature and high pressure to make a renewable crude bio-oil, is receiving increased attention. Understanding the governing reaction pathways for the biomolecules in the microalgae cell could lead to improved conversion processes. This review collects information pertinent to the behavior of microalgae biomolecules (e.g., proteins, polysaccharides, lipids, chlorophyll) and their hydrothermal decomposition products (e.g., amino acids, sugars, fatty acids) in high temperature water (HTW). We report on studies involving individual compounds and their mixtures. The mixture systems are particularly important as they move closer to mimicking the true chemistry of HTL of microalgae by providing opportunities for interactions between different molecules that would be present during HTL. Throughout this review, we highlight gaps in the understanding of different chemical reactions that may take place during HTL of microalgae.

Silver Oxide as Superb and Stable Photocatalyst under Visible and Near-Infrared Light Irradiation and Its Photocatalytic Mechanism

Abstract: Photocatalytic processes are an environmentally friendly technology for treatment of persistent organic pollutants. However, the majority of current photocatalysts cannot utilize sunlight sufficiently to realize fast decomposition of organic pollutants. In this research, a silver oxide nanoparticle aggregation with superb photocatalytic performance under artificial light source and sunlight was prepared and characterized. The results showed that methyl orange (MO) was decomposed completely in 120 s under irradiation of artificial visible light, artificial ultraviolet light, and sunlight, and in 40 min under near-infrared (NIR) light. The superb photocatalytic performance of as-prepared silver oxide remained almost constant after reuse or exposure under sunlight. It was confirmed that the co-working effect of photogenerated hole and ozone anion radicals did play an important role in the process of MO photodegradation with the existence of Ag2O. The narrow band gap of Ag2O, less than 1.3 eV, resulted in the...

Fabrication of Poly(lactic acid)/Graphene Oxide Foams with Highly Oriented and Elongated Cell Structure via Unidirectional Foaming Using Supercritical Carbon Dioxide

Abstract: The significant influence of graphene oxide (GO) on the unidirectional foaming of poly(lactic acid) (PLA) using supercritical CO2 as blowing agent was investigated in this study for the first time. Highly oriented and elongated cell structures were obtained from the PLA/GO nanocomposites foams. The thermal, rheological, and CO2 absorption properties of the PLA/GO nanocomposites were studied to investigate the effect of GO on PLA unidirectional foaming. It was found that the incorporation of GO improved the storage modulus, loss modulus, and complex viscosity of the PLA/GO nanocomposites significantly. The addition of GO improved the CO2 absorption ability of the nanocomposites, which caused high expansion ratio and increased average cell size during foaming process. The high expansion force by enhanced CO2 absorption, high matrix viscosity of PLA/GO nanocomposites, and restriction of the mold in three directions together caused the formation of the highly elongated cell structure during foaming.

Phosphotungstic Acid Supported on Mesoporous Graphitic Carbon Nitride as Catalyst for Oxidative Desulfurization of Fuel

Abstract: The phosphotungstic acid/mesoporous graphitic carbon nitride catalyst was successfully prepared by immobilizing phosphotungstic acid (H3PW12O40, HPW) on mesoporous graphitic carbon nitride (mpg-C3N4). The prepared series of HPW/mpg-C3N4 catalysts was characterized via X-ray diffraction, nitrogen adsorption–desorption isotherm, Fourier transform infrared spectroscopy, transmission electron microscopy, inductively coupled plasma atomic emission spectroscopy, and thermogravimetric analysis. Results showed that the Keggin structure of HPW active species is still kept after being immobilized on the mpg-C3N4 surface. The HPW/mpg-C3N4 catalyst showed a high catalytic activity in the oxidative desulfurization process. Dibenzothiophene can be removed completely under optimal reaction conditions, and no significant decrease in the catalytic activity of the catalyst was observed after 15 recycles.

A Review on Flux Decline Control Strategies in Pressure-Driven Membrane Processes

Abstract: Concentration polarization(CP) and membrane fouling are two major drawbacks for pressure-driven membrane filtration processes (PDMPs) because they cause severe flux decline, which requires effective control strategies. Many articles have proposed the diverse potential applications of various Control strategies in reducing CP and membrane fouling. This paper reviews various mechanisms and influencing factors on flux decline, as well as their control strategies in PDMPs. Nine effective control strategies are summarized, generalized, and compared in this paper. On the basis of their functions and influences, they can be also classified as the following: (1) modification: pretreatment of feed, modification of feed characteristics, selection and modification of membrane; (2) design: shear-enhanced filtration modules, applied field enhancement and CP drawer; (3) operation: optimization of operating parameters, hydraulic flushing and two-phase flow. Then, the general and practical guidelines are given. On the basis of this review, future research perspectives related to flux decline control strategies are proposed.

Electrospun Microfibrous Membranes Based on PIM-1/POSS with High Oil Wettability for Separation of Oil–Water Mixtures and Cleanup of Oil Soluble Contaminants

Abstract: A series of PIM-1/POSS microfibrous membranes were fabricated by electrospinning technology. The addition of POSS particles could greatly enhance the hydrophobicity, and a superhydrophobic–superoleophilic membrane was obtained as the POSS concentration increased to 40 wt %. The scanning electron microscopy images indicate that the incorporation of POSS particles results in formations of hierarchical structures on the surface of the PIM-1/POSS fibers. Both the intrinsic hydrophobic nature of POSS and the increase in the fiber surface roughness led to the superhydrophobicity and superoleophilicity. The 40 wt % PIM-1/POSS fibrous membrane could not only separate a wide range of immiscible oil–water mixtures with efficiencies higher than 99.95% but also separate water-in-oil emulsions with efficiencies higher than 99.97%. Furthermore, because of the ultrahigh intrinsic microporosity of the PIM-1 polymer, the PIM-1 fibrous membrane exhibited the ability to adsorb a large amount of contaminants such as oil red ...

Graphitic Biocarbon from Metal-Catalyzed Hydrothermal Carbonization of Lignin

Abstract: Lignin is a high-volume byproduct from the pulp and paper industry and is currently burned to generate electricity and process heat. The industry has been searching for high value-added uses of lignin to improve the process economics. In addition, battery manufacturers are seeking nonfossil sources of graphitic carbon for environmental sustainability. In this work, lignin (which is a cross-linked polymer of phenols, a component of biomass) is converted into graphitic porous carbon using a two-step conversion. Lignin is first carbonized in water at 300 °C and 1500 psi to produce biochar, which is then graphitized using a metal nitrate catalyst at 900–1100 °C in an inert gas at 15 psi. Graphitization effectiveness of three different catalysts—iron, cobalt, and manganese nitrates—is examined. The product is analyzed for morphology, thermal stability, surface properties, and electrical conductivity. Both temperature and catalyst type influenced the degree of graphitization. A good quality graphitic carbon was...

Synthesis, Characterization, and Utilization of a Novel Phosphorus/Nitrogen-Containing Flame Retardant

Abstract: The novel phosphorus/nitrogen-containing flame retardant hexa(phosphaphenanthrene aminophenoxyl)cyclotriphosphazene (HPAPC), which contains phosphaphenanthrene [9,10-dihydro-9-oxa-10-phosphaphenanthrene 10-oxide (DOPO)] and phosphazene (hexachlorocyclotriphosphazene) groups, was synthesized by the classic Atherton–Todd reaction, and its chemical structure was characterized by Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopies. Poly(lactic acid) (PLA) composites containing HPAPC were prepared by melt blending, and their fire performance and thermal behaviors were investigated in terms of limiting oxygen index (LOI), vertical burning (UL-94), cone calorimeter tests, and thermogravimetric analysis (TGA). The LOI value could reach up to 34.7%, and UL-94 could pass V-0 for the PLA composite containing only 5 wt % HPAPC. TGA results showed that the char formation of PLA could be significantly improved by the presence of HPAPC. The evolved gas of the composite was analyzed by F...

Direct Capture of Low-Concentration CO2 on Mesoporous Carbon-Supported Solid Amine Adsorbents at Ambient Temperature

Abstract: The CO2 dynamic adsorption behaviors of the mesoporous carbon-supported solid amine adsorbents and their viability for low-concentration CO2 capture were investigated in a fixed bed. The CO2 diffusion, playing a dominate role on the CO2 reaction-adsorption process, was addressed from the following two strategies: improving the support and facilitating the kinetic diffusion. The well-developed mesoporous carbon framework could accommodate high content of polymer amine polyethylenimine (PEI) while maintaining considerable residual channels for CO2 inner pore diffusion. Moreover, the kinetic limitation to CO2 diffusion within the amine films could be mitigated by the employment of a diffusion additive, which could facilitate the diffusion of CO2 into the internal PEI films. The as-prepared MC-based solid amine adsorbents exhibit remarkable adsorption capacities of 3.34 mmol·g–1 for 5000 ppm of CO2 and 2.25 mmol·g–1 for 400 ppm of CO2. The CO2 adsorption capacity of the adsorbent increases significantly in th...

One-Step Ball-Milling Preparation of Highly Photocatalytic Active CoFe2O4–Reduced Graphene Oxide Heterojunctions For Organic Dye Removal

Abstract: We prepared CoFe2O4–RGO (RGO: reduced graphene oxide) composites by ball-milling without using toxic chemical reagents and high-temperature heat treatment. The exfoliation and reduction of graphite oxide and anchoring of CoFe2O4 nanoparticles on graphene sheets were accomplished in one step. The microstructure of the heterophotocatalyst was characterized by X-ray diffraction, Fourier transform infrared, Raman and transmission electron microscopy methods. The photocatalyst exhibited desirable photocatalytic performance with excellent recycling stability for the degradation of methylene blue, rhodamine B and methyl orange under visible-light irradiation. In addition, the CoFe2O4–RGO photocatalyst can be easily separated by an external magnetic field. The simple and efficient one-step ball-milling strategy for preparing the photocatalysts is more applicable to industrial production.