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Selective non-catalytic reduction (SNCR) with NH

Pseudocapacitive asymmetric supercapacitors are promising candidates for achieving high energy density in flexible energy storage devices. However, seeking suitable positive electrode materials that are compatible with negative electrode materials remains a considerable challenge. In the current study, a pseudocapacitive Ti3C2Tx MXene used as negative electrodes is rationally compatible with redox-type V2O5 as positive electrodes, resulting in the assembly of an all-pseudocapacitive Ti3C2Tx MXene//V2O5 asymmetric flexible energy storage device. The solid-state asymmetric device can deliver an energy density of 8.33 mW h cm-3 at a current density of 0.5 A g-1. Moreover, it can operate in an expanded voltage window of 1.5 V, with dominant surface-capacitive charge-storage mechanisms. Additionally, the device can power a yellow light-emitting diode for up to 7 s, indicating the potential of the device for use in practical applications. This study demonstrates the possibility of using other two-dimensional transition-metal carbide nanosheets for high-energy density flexible energy storage devices.

Development of sustainable routes to synthesize precious metal supported catalysts is of great importance because of their wide applications in the catalysis field. This paper reported a controllable and recyclable cation-assisted reduction route to fabricate a palladium nanoparticle supported catalyst. At 323 K, highly dispersed Pd/Al2O3-CARM was prepared through introducing M2+ (M = Mn, Zn or Cu) ions to promote the reduction of H2PdCl4 in ethylene glycol–water solution, and the residual filtrate after preparation could be recycled to prepare Pd/Al2O3 catalysts. A turnover frequency of 300 × 102 h−1 was obtained for Pd/Al2O3-CARMn in solvent-free aerobic oxidation of benzyl alcohol to benzaldehyde.

Carbonate esters and esters were commonly used as solvents, reaction carrier, and additives in organic synthesis, the pharmaceutical industry, and processing industries. Vapor–liquid equilibrium (V...

Pd–Cu(Ni) bimetallic catalysts supported on Pb-doped manganese oxide octahedral molecular sieves(Pb-OMS-2) were prepared by deposition-precipitation method, and the activities of those bimetallic catalysts were evaluated in the oxidative carbonylation of phenol to diphenyl carbonate (DPC). The physico-chemical properties of catalysts were evaluated by various characterization techniques such as X-ray diffraction (XRD), Transmission electron microscope (TEM), Scanning transmission electron microscopy/energy-dispersive X-ray spectroscopy (STEM/EDS), Temperature-programmed reduction of hydrogen (H2-TPR) and X-ray photoelectron spectroscopy (XPS). The results showed that superior activity of bimetallic catalyst was accomplished by the addition of second metal Cu(Ni) compared to monometallic Pd catalyst. The metal particles of bimetallic catalysts were dispersed homogeneously on the surface with small particle size (3∼5 nm). The high activity and stability of bimetallic catalyst were achieved due to the formation of very active Pd–Cu(Ni) interfaces. The oxidation state of active species increased via the strong interaction between bimetallic components, and the redox capacity of Pd became stronger with the addition of the second metal. The highest DPC yield was 23.4% for Pd1Cu2 and 22.9% for Pd1Ni4 catalysts, respectively. After 20 h of reaction time, even though the DPC yield stopped growing for the monometallic catalysts, it continued to increase for the bimetallic catalysts, and the DPC yield reached about 50.0% at 24 h.

Flotation has become a significant technique for the KCl separation from NaCl-containing complex systems, but the true nature of adsorption selectivity of collector on the crystal surface of KCl is still unclear. In this study, using density functional theory calculations, we investigated the adsorption behaviors of a commonly used collector, octadecylamine hydrochloride (ODA), on the crystal surfaces of KCl and NaCl, respectively. The results demonstrate that the structure of built crystals for calculation is validity and the crystal surfaces containing two-layer atoms are most stable. All adsorption energies of ODA+ cation and H2O molecule on the crystal surfaces of KCl and NaCl are negative with the decreased absolute value according to the sequence of KCl-ODA+ >NaCl-H2O > KCl-H2O > NaCl-ODA+, suggesting that the interaction between ODA and KCl is stronger than that in the other considered systems. The differences of interaction energies demonstrate the adsorption selectivity of ODA on KCl, resulting in the selectively flotation. Therefore, we construct accurate models to simulate the actual crystal surface structures of KCl and NaCl, and we provide adsorption energies as complementary evidences to interpret the floatability of KCl from the NaCl mixture, which can help to design new collectors for the flotation of soluble salts.

In this paper, a new mixed steepest descent algorithm which has short computation time and stable solution is provided. Comparisons and case studies based on different traffic network and distance are made with other intelligent and exact algorithms. The large-scale experiment shows that the possibility of securing the optimal solution is greater than 99.5% and the average computation time is lower than 0.06 s when the node scales are less than 50. The proposed algorithm can not only be applied in emergency logistics problems but is also useful for solving other real-world problems.

Carbonate esters and esters are widely used in the pharmaceutical industry. It is important to enrich the vapor–liquid equilibrium (VLE) database of these components. In this article, the isobaric ...

The extensive researches about the thermodynamic and intrinsic kinetic of disproportionation reaction of methyl phenyl carbonate to diphenyl carbonate were investigated independently with dibutyltin oxide as a catalyst, at a temperature range of 433.15–473.15 K and different catalyst concentrations in a stirred batch reactor, for a deeper knowledge of reaction essence. This reaction was found endothermic and showed hardly any reaction in the absence of catalyst which indicate an inferior kinetic characteristics. The reaction rate increases with an increasing catalyst concentration until the concentration went to 8.08 × 10−4 mol mol−1. A possible mechanism involving an in-situ Sn-based species was proposed and finally verified by a good agreement between experimental and simulated data. The available Sn-based species was then demonstrated to play a real catalytic role by extra experiments. All results can also be further utilized to explore the essence of transesterification reaction network.

As one of the typical solid-wastes, FGD gypsum usually occupies land and causes resource waste and environmental pollution. Its high content of CaSO4·2H2O shows highly potential in synthesizing CaCO3 by incorporating CO2. Nevertheless, the impurities in FGD gypsum have significant effects on polymorph of CaCO3 and the formation mechanism of CaCO3 polymorph during FGD gypsum carbonation was still unclear. Here, we selected CaSO4·2H2O as model to explore the effects of impurities of muscovite and dolomite in FGD gypsum on polymorph of CaCO3 during carbonation. Results showed that the carbonation products of FGD gypsum are a mixture of vaterite (˜60%) and calcite (˜40%), while only pure vaterite was obtained in CaSO4·2H2O carbonation reaction. Muscovite has negligible effects on obtaining pure vaterite during CaSO4·2H2O carbonation. Interestingly, the content of calcite increases to the maximum value (˜27%) at 1.0 wt% dolomite and then decreases with the increment of dolomite in CaSO4·2H2O carbonation reaction. Correspondingly, vaterite declines first and then increases. Mechanism study shows that hydrophilicity and negative surface charge of dolomite might be the key factors to selectively form calcite during the carbonation of FGD gypsum. These findings might contribute to further utilization of FGD gypsum.

In order to reduce the wetting and fouling propensity of polyvinylidene fluoride (PVDF) membrane during coking wastewater treatment by membrane distillation, two kinds of omniphobic PVDF composite membranes were prepared by coating SiO2 nanoparticles on PVDF membrane surface via electrostatic adsorption or chemical bonding respectively, and subsequently fluorination. The coated SiO2 nanoparticles observed as amounts of nano-scale protrusions by scanning electron microscope constructed a re-entrant structure and enhanced membrane surface roughness. The omniphobicity of the modified membranes was confirmed by high contact angles (> 150°) for water, diiodomethane and ethylene glycol on the membrane surface. The omniphobic layer with SiO2 nanoparticles coated via chemical bonding was more stable than electrostatic adsorption. Both the omniphobic PVDF membranes exhibited stable and high rejections of the inorganic and organic contaminants, which were determined by conductivity, total organic carbon and three-dimensional excitation-emission fluorescence spectroscopy of the distillate. The modified omniphobic membranes also showed much less flux decline than the pristine PVDF membrane in direct contact membrane distillation tests (120 h), suggesting their excellent anti-fouling performance. This study indicates that coating silica nanoparticles via chemical bonding is an effective and promising method to fabricate omniphobic PVDF membrane for coking wastewater treatment.

Graphene oxide (GO) coating has recently been reported as a novel approach to increase membrane flux of membrane distillation (MD), yet the phenomena underlying the process are still not fully understood. In this study, a mathematical model based on capillary-film assumption was developed and validated with the results (R

Pseudocapacitive asymmetric supercapacitors are promising candidates for achieving high energy density in flexible energy storage devices. However, seeking suitable positive electrode materials that are compatible with negative electrode materials remains a considerable challenge. In the current study, a pseudocapacitive Ti

TiO2 nanowires (NWs) membranes with varied wettability ranging from superhydrophilic to superhydrophobic have been facile fabricated via dip-coating for oil/water separation. Incorporating TiO2 NWs results in the increase of roughness and the formed hierarchical structure from TiO2 NWs micro-aggregations enlarges the wettability. Separation efficiency and permission flux of the as-prepared membranes increase first and decrease with the increment of TiO2 NWs. These superhydrophilic/hydrophilic membranes eliminate water from oil/water mixtures and the separation efficiency declines with the increasing water contact angle until the membrane lose the oil/water separation property at around 90°. Membranes with water contact angle of 90–100° cannot separate oil/water mixtures while membranes with water contact angle larger than 120° become oil-remove type with separation efficiency around ~ 99% and high permission flux. The study illustrates that relatively large pore size (~ 15 µm) attributes to the high separation efficiency and permission flux. The synergetic effects of wettability and pore size indicate that surface wettability is critical for efficient oil/water separation. Both hydrophilic and superhydrophilic membranes show high separation efficiency and outstanding anti-fouling performances after long term oil/water separation.

With the burden of city transportation system becoming bigger and bigger, it is imperative to develop reliable and efficient underground logistics. The appropriate location of cargo transshipment centers in underground logistics system is selected using the Set Covering Problem Model, Weighted Set Covering Problem Model, and the reasonable prediction of the freight volume data of major cities to ensure the maximum numbers of service nodes are covered by the least transshipment centers within a reasonable range. The timing of the construction of facilities in the system is proposed, considering the construction cost and cost recovery period of the underground logistics system. The design and optimization plan of the urban underground logistics system, based on the above, is given to achieve the purpose of relieving urban traffic congestion and increasing freight volume.

The accidents caused by hazardous material during road transportation may result in catastrophic losses of lives and economics, as well as damages to the environment. Regarding the deficiencies in the information systems of hazmat transportation accidents, this study conducts a survey of 371 accidents with consequence Levels II to V involving road transportation in China from 2004&ndash, 2018. The study proposes a comprehensive analysis framework for understanding the overall status associated with key factors of hazmat transportation in terms of characteristics, cause, and severity. By incorporating the adaptive data analysis techniques and tackling uncertainty, the preventative measures can be carried out for supporting safety management in hazmat transportation. Thus, this study firstly analyzed spatial&ndash, temporal trends to understand the major characteristics of hazmat transportation accidents. Secondly, it presents a quantitative description of the relation among the hazmat properties, accident characteristics, and the consequences of the accidents using the decision tree approach. Thirdly, an enhanced F-N curve-based analysis method that can describe the relationship between cumulative probability F and number of deaths N, was proposed under the power-law distribution and applied to several practical data sets for severity analysis. It can evaluate accident severity of hazmat material by road transportation while taking into account uncertainty in terms of data sources. Through the introduction of the as low as reasonably practicable (ALARP) principle for determining acceptable and tolerable levels, it is indicated that the F-N curves are above the tolerable line for most hazmat accident scenarios. The findings can provide an empirically supported theoretical basis for the decision-makers to take action to reduce accident frequencies and risks for effective hazmat transportation management.

Prenatal DEHP exposure can cause offspring neurodevelopmental toxicity, but the persistent effects of such exposure window are unclear. This study aimed to investigate the lasting neurobehavioral impact of DEHP on offspring following early exposure from GD9.5 (fetal neural tube closure) to GD16.5 (fetal thyroxin, TH, synthesis). Data showed maternal exposure to DEHP during the thyroid hormone-dependent stage induced a range of neurobehavioral phenotypic changes in adult and middle-aged mice, including anxiety, depression and cognitive impairment. Significant reductions in free TH, TH transporters, and TH metabolic enzyme deiodinase II (D2) were observed in the fetal brain, whereas D3 was elevated, indicating that TH signaling disruption was caused by in utero exposure. Gene expression analyses suggested the expression levels of the TH receptors Trα1, Trβ1 and their downstream target, brain-derived neurotrophic factor, were significantly attenuated, which may partially explain the mechanisms of neurodevelopmental impairment. This study provides new evidence of the persistent effects of sex-specific neurodevelopmental impairment due to in utero DEHP exposure, possibly through damage to the fetal brain TH signaling systems that causes lifelong brain damage. These results further suggest a profound neurobehavioral toxicity of DEHP that may be programmed during early developmental stage exposure and manifested later in life.

Bio-refractory organic contaminants (BOC) originating from coking wastewater is a severe threat to the environment and human health. The efficient pretreatment of coking wastewater is necessary to decrease the stress of the biological treatment stage. For pretreatment, the development of effective flocculants is needed. In this work, a novel inorganic–organic hybrid flocculant, polyaluminum silicate chloride–polyacrylamide–acryloyloxyethyl dimethylbenzyl ammonium chloride (PASi-P(AM-ADB)), was prepared and its flocculation behavior for raw coking wastewater were investigated. Flocculation results showed that this hybrid flocculant exhibited significantly higher removal efficiency than two other common flocculants, polyaluminum chloride and cationic polyacrylamide. Gratifyingly, the PASi-P(AM-ADB) can also efficiently remove refractory organic contaminants during the process of flocculation, as demonstrated by gas chromatography–mass spectrometry (GC–MS). Particularly, several polycyclic aromatic hydrocarbons, defined as persistent organic pollutants, are removed completely. Here, we demonstrated that this new hybrid flocculant presented outstanding flocculation properties as well as high-efficient removal of some special BOC from raw coking wastewater. This work might provide new insights into the design of functional inorganic–organic hybrid flocculants and enhance the treatment of complex industrial wastewater.

Four glycosyl-modified polysiloxane (GPSO) biosurfactants were designed and synthesized via two-step reactions using green materials. The physicochemical properties: surface activity and aggregation behaviors in aqueous solution were systematically investigated. Investigation of the surface tension indicates that GPSO have relatively low critical aggregation concentrations (CAC) and surface tensions at CAC (γCAC) compared with hydrocarbon surfactant. Adsorption at the air-water interface and the formation of micelles in aqueous are spontaneity and the tendencies of adsorption are favored over the process of micellization. Dynamic surface tension results indicate that D-glucoheptono-1, 4-lactone modified polysiloxanes (GHL@Si) have good diffusion ability than that of glucono-δ-lactone modified polysiloxanes (GL@Si). Transmission electron microscopy (TEM) and Dynamic light scattering (DLS) results indicate that part of biosurfactants can form spherical aggregates.

Poly-aluminum-ferric-silicate-chloride (PAFSiC) coagulant was synthesized using coal gangue as raw material. The effect of silicon content on its chemical structure, coagulation performance and floc properties were systemically investigated. Results show that coal-gangue-derived PAFSiC consists of new species with silicon-oxygen-metal bonds and impurities like NaAl(SiO3)2 and K4Ca(SiO3)3. The Si-O-Al and Si-O-Fe bonds were increased with the increase of silicon content. However, a certain amount of silicon ((Al + Fe)/Si molar ratio of 10:1–13:1) is required for the chain-net structure formation, too high or too low silicon content would lead to the destruction of this structure. The jar-test results showed that the best removal of color, UV absorbance at 254 nm and dissolved organic carbon was achieved at same (Al + Fe)/Si molar ratio (10:1–13:1). Moreover, the PAFSiCs with (Al + Fe)/Si molar ratio of 10:1 and 13:1 also demonstrated the highest floc strength and floc fractal dimension, which implying better settling ability in the subsequent sedimentation process. This study indicates that the introduction of silica into the hydrolyzing metal helps to increase the molecular size and enhance the bridge-aggregating ability of the coagulant. However, a proper silicon content is required for obtain the optimal coagulation performance and floc properties for coking wastewater treatment.

The surface properties and flotation response of coal samples of different rank correspond to results from similar experiments for coal samples with different degrees of oxidation. Three principal ...

Hydrolytic stability, foaming power and foam stability, calcium soap dispersing ability and stability in hard water of fatty acid methyl ester sulfonate (MES) were measured by potentiometric titrat...

In this paper, the physicochemical properties between sodium dodecylbenzenesulfonate (SDBS) and polyvinylpyrrolidone (PVP) in aqueous solutions were studied at 25 °C by Ubbelohde viscometer, conductivity analyzer, and fluorescence spectrophotometer. It was found that viscosity, conductivity, steady-state fluorescence, and Rayleigh scattering curve for SDBS-PVP system could be divided into three regions by two characteristic concentrations: the critical aggregation concentration (cac) and the polymer saturation point (psp). The results revealed that interactions between SDBS and PVP molecules in aqueous solutions could be explained by “necklace and bead” model. Micelle-like surfactant aggregates, formed by SDBS-free molecules, associated with PVP chains mainly by hydrophobic interaction.

In this paper, a game model composed of three subjects — government, manufacturer and consumer has been built by using Evolutionary Game Theory on the basis of analyzing the trilateral game strategy of waste mobile reverse supply chain based on ECP; an evolutionary equilibrium model is to be sought for by utilizing the replication dynamic differential equation method; and the trilateral game strategy’s revolutionary trend and consistency have been analyzed by means of SD simulation method when government implements the static or dynamic reward and punishment strategy. The finding results reveal that, under the static reward and punishment strategy, the revolutionary process of trilateral game strategy is always unstable whether the initial behavior strategy is unitary or mixed. Therefore, it is more reasonable for the government to adopt the strategy of dynamic reward and punishment, and it is also stable and reciprocal for all the stakeholders when implementing this strategy.

BACKGROUND Bio-treated coking wastewater is difficult to treat further, mainly due to the bio-refractory organic content. Coal gangue is the largest solid waste in China and it contains large amounts of aluminum, iron and silicon. This study attempts to recover the waste of coal gangue as a novel poly-silicic metal coagulant for bio-treated coking wastewater treatment. RESULTS The poly-silicic metal coagulant was synthesized from coal gangue under different conditions. Fourier transform infrared spectroscopy, X-ray diffraction and scanning electron microscopy confirmed that both amorphous and crystalline phases were present in the samples and new chemical bonds such as Si-O-Al and Si-O-Fe were formed. The results show that the composite coagulant was effective for organic removal from the bio-treated coking wastewater and the optimal Al/Fe/Si molar ratios were Al/Fe = 3 and (Al + Fe)/Si = 13. The removal of organics exhibits a parabolic curve as the coagulant dosage increases. However, the optimal dosage (125 mg/L) for organic removal was not equal to the isoelectric point (100 mg/L). Furthermore, the SEM images showed that the flocs start to disintegrate at the dosage of 150 mg/L, leading to deteriorating sludge settling. CONCLUSIONS It is feasible to fabricate poly-silicic metal coagulants for coking wastewater treatment by using use coal gangue as the raw material. The removal of the bio-refractory organics by the composite coagulant was attributed to the combined effects of charge neutralization, bridge adsorption and the net capturing.

Three polycarboxylate-based comb-like random terpolymers (PAE-Na) were designed and synthesized by emulsion polymerization. Their structures were confirmed by FT-IR, 1H NMR and GPC. Their surface activities, aggregation behaviors and dispersity properties in aqueous solution were investigated by surface tension measurements, dynamic light scattering (DLS) and transmission electron microscopy (TEM). Investigation of the surface tension indicates that polycarboxylate-based copolymers have good surfactivity due to the introduction of 2-ethylhexyl acrylate (2-EHA). And it is noteworthy that γ continuously decreases after critical aggregation concentration (CAC). TEM and DLS results indicate that they can form the aggregates of primary aggregates. The dispersibility of terpolymers as dispersant for CaCO3 suspensions was evaluated. The results show that the target polymers have good dispersive capacity. The thermogravimetric analysis indicates that terpolymers have excellent thermal stability, which could be used to disperse solid particles in many different fields.

The structure of polyelectrolyte substrates could be changed from swelling to collapse by exchanging different electrolyte solutions. However, few investigations explained the phenomenon at the molecular level. In this paper, we employed a molecular dynamics method to simulate the structural changes of poly(methacrylic acid sodium) (PMMA) substrates with the presence of pure water, NH4Cl, tetramethylammonium bromide (TMAB) and tetraethylammonium bromide (TEAB) solution. The simulated results show that the percentage of water molecules penetrated into the substrate and the height of PMMA substrates gradually decrease following the order pure water > NH4+ > TMA+ > TEA+. This may be ascribe to the hydrophobic interaction between the solute cations and water molecules, which can exclude water molecules from the substrates and further influence the height of PMMA substrates. In particular, through the observation at the molecular level, it is obvious that the existence of water bridge structure and salt bridge structure formed between penetrated particles and PMMA chains play a key role in the structural change of PMMA substrates. Water bridges can induce the swelling of PMMA substrates and salt bridges will result in collapse happening. This work may promote a further understanding of the cationic effects on the structure of PMMA substrates at the molecular level and provide a new insight to study the interfacial micro-structure of other biological substrates in future.

The spread of collector molecules on bubble surfaces in salt solution is a fundamental phenomenon in the froth flotation of soluble salts, such as KCl, and consideration of ionic effects on adsorption behavior and packing of collector molecules at the air/solution interface is appropriate for study. In this work, specific anion effects on the adsorption and packing of one common collector (octadecylamine hydrochloride, ODA) at the air/water interface were investigated by employing a combination of surface pressure measurements, sum frequency vibrational spectroscopy (SFVS) and molecular dynamics simulations (MDS). The results from experiments and MDS showed that the addition of external anions disturbs the arrangement of ODA molecules due to the penetration of these anions from the water subphase into the ODA monolayer at the air/water interface. During monolayer compression, the penetrated anions might be driven back to the water subphase by electrostatic forces and the added compression force. These anions could screen the charge of NH3 groups resulting in a reduction of the minimum area of the ODA molecule (Amin) for the solid phase state of the monolayer. With the exception of the sulfate anion, the added anions increase hydrogen bonding of interfacial water molecules at the air/water interface. These results allow for a better understanding of the anionic effect on adsorption and packing of ODA molecules at the air/water interface, and might therefore provide new insights into froth flotation of soluble salts and should help to improve soluble salt flotation technology.

In mixtures of sodium perfluoropolyether carboxylate (PFPE-Na) and cetyltrimethylammonium bromide (CTAB) in dilute solutions, the surface activities and aggregation behaviors have been investigated by the surface tension, dynamic surface tension, contact angle methodologies, dynamic light scattering (DLS), transmission electron microscopy (TEM) and dye encapsulation experiments. The surface tension measurements provided the critical micelle concentration (CMC) and the surface tension at the CMC (γCMC) at different molar ratios. In addition, surface activity parameters of the maximum surface excess concentration (Γmax) and the minimum surface area/molecule (Amin) at the air/water interface were evaluated. The adsorption and wetting abilities of FC-poor mixed systems were studied. Mixed systems of fluorocarbon - hydrocarbon surfactants show better ability to reduce the surface tension and more efficiency to reduce the surface tension. Adding tiny amount of PFPE-Na to CTAB solution (1:20–1:50) has little effect to adsorption, but it enhances the surface activity and wetting ability of mixed system distinctly. Meanwhile, the mixed system can form stable vesicle spontaneously near the PFPE-Na/CTAB ratio of 2:1 in aqueous solution, it may be used as drug delivery vehicles and cold be used as micro/nanotemplates for material synthesis [1–4].