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Selective non-catalytic reduction (SNCR) with NH

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.

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.

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.

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.

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.

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].

A simple process to synthesize polyglycerol modified polysiloxane surfactants has been carried out applying a “grafting-to” approach. After formation of allyl polyglycerol ether (APGE) from diglycerol (DGY) and allyl glycidyl ether (AGE), polysiloxane modified by designed number of polyglycerol groups (PHMS-APGE) were obtained by connecting the APGE structure to different Si H functionalized polyhydromethyl siloxane (PHMS). The synthesized APGE-PHMS were characterized by IR and 1H NMR. Solubility measurements showed that the solubility of the as-prepared polymers increased in polar solvents with the increasing of the amount of hydrophilic APGE groups. Furthermore, the surface activity, surface adsorption, aggregation and spreading behaviors of APGE-PHMS were investigated utilizing surface tension measurements, dynamic light scattering (DLS), transmission electron microscopy (TEM) and contact angle measurements. The results showed that critical aggregation concentration (CAC) and the time needed to reach adsorption equilibrium on water surface decrease systematically with the increase in the number of APGE groups. These polymers in aqueous solutions could aggregate to form spherical assemblies. Moreover, the spreading behavior of these polymers on low energy surface was found to be influenced by the number of hydrophilic APGE groups.

Microbial fuel cell (MFC) is commonly used for easily biodegradable substances, yet its application for high strength phenolic wastewater treatment remains a challenge. This study incorporates lignite activated coke (LAC) into MFC to alleviate the inhibition of phenol and facilitate power generation of MFC. The power generation and phenol degradation in both LAC-MFC and control MFC were investigated at phenol concentrations of 500 mg/L, 700 mg/L and 1000 mg/L. The results showed that the maximum power density in LAC-MFC was maintained in the range of 252.3–278.7 mW/m2 when the phenol concentration increased from 500 mg/L to 1000 mg/L, whereas it was decreased from 246.5 mW/m2 to 167.5 mW/m2 in control-MFC. This corresponds to a high phenol removal of 89.4% to 94.5% in LAC-MFC but a significant decrease from 80.7% to 50.8% in control MFC. The inhibition coefficient (Ki) calculated from Haldane inhibition model decreased by 24.3% in LAC-MFC compare with control MFC, suggesting that the stress of high concentrations of phenol on MFC was largely relieved. In addition, the phenol degradation intermediate products of 2-hydroxymuconic semialdehyde, 4-hydroxybenzoic acid, 4-hydroxy-3-methylbenzoic acid were apparently lower in LAC-MFC than control MFC, indicating that the biodegradation of phenol was enhanced in LAC-MFC. High-throughput sequencing analysis revealed that Pseudomonas, Desulfuromonas, and Hydrogenophaga might be associated with phenol degradation and power generation in LAC-MFC. Because of its effectiveness in alleviating the toxic effects of phenol, LAC packing is a promising MFC technology for high strength phenolic wastewater treatment.

To achieve effective oil/water separation, one-step facile fabricated hydrophobic SiO2 coated super-hydrophobic/super-oleophilic mesh (FSSM) via an improved Stober method. Apparent contact angle was characterized by a contact angle meter (CA). SEM, FTIR and XPS were used to characterize the surface morphology and chemical composition of FSSM, individually. The super-hydrophobicity of the membrane was conferred by the multistage rough structure and low surface energy substances produced by the hydrolysis and polycondensation reactions of TEOS, DTMS and TMODS. Meanwhile, the effect of the proportion for silane coupling agents DTMS and TMODS on the hydrophobicity from claiming stainless steel network surfaces was investigated. The results showed that when DTMS: TMODS = 1:9 (n: n), the maximum apparent contact angle of FSSM was 153.3°, while the apparent contact angle of oil was 0°. The C, O and Si elements on the surface of FSSM increased by approximately 21%, 9% and 20% respectively. The FSSM can efficiently separate different oil/water mixtures (about 96%). Furthermore, FSSM showed excellent anti-corrosion (pH from 0 to 14) and remarkable reusability (about 40 cycles) and durability (exposure test at atmosphere for 35 days). The advantages of easy manufacture, stability and low cost of FSSM make it expected to be widely used in the field of oil-water separation.

Flotation continues to be a major technique for the production of potash from low grade, complex systems containing a variety of ores and ions. The specific ion effects on the behavior of the flotation collector in the KCl flotation system becomes important to the interpretation of the flotation mechanism. In this work, specific ion effects on the turbidity, surface tension and aggregation behavior of the common collector in KCl flotation, octadecylamine hydrochloride (ODA), have been investigated. The results from turbidity and surface tension studies of ODA solutions show that both cations and anions can affect the colloidal properties of ODA. Molecular dynamics simulations show that the binding that energy barrier between ODA headgroups and anions is principally responsible for the specific anion effect of γ CAC of ODA solutions. In addition, the ion effect on the ODA aggregation particle size was also studied by using transmission electron micrographs (TEM) and dynamic light scattering. The data reveal that the presence of salt ions can induce the formation of larger ODA colloidal particles, on which the cation effect is more significant. This work provides detailed information of specific ion effect on colloidal properties of ODA, which may promote a further understanding of the flotation mechanism and help to improve the flotation of KCl from brine sources.

Polycarboxylate-based terpolymers with different PEG length, PAE-Na, were synthesized by free radical emulsion polymerization. The monomers are Poly(ethylene glycol) monomethyl ether monomethacrylate (PMEM, Mn = 950 g/mol, 500 g/mol and 300 g/mol), 2-ethylhexyl acrylate (2-EHA) and acrylic acid (AA), respectively. The structures of terpolymers were characterized by 1H NMR and FT-IR. This particular molecular structure of terpolymers guarantees its good dispersibility. Here, PAE-Na terpolymers were used as dispersant and CaCO3 as solid suspension to calculate the dispersion amounts (DAs) by means of titration method. PAE-Na terpolymers with different PEG length show great differences in DAs. Furthermore, the particle size distribution (PSD) and transmission electron microscopy (TEM) were carried out to evaluate the particle size of CaCO3 suspensions. The experiment results show that the dispersibility of terpolymers has an increasing trend while increasing the PEG side chain length. Based on the theory of Flatt and Scaling law, the molecule size of terpolymers with different length of PEG side chain was calculated. The Flory energy as a function H was calculated when two particles approach. Finally, the anti-redepositing power of 3# terpolymer was investigated. The result shows that 3# terpolymer has strong anti-redepositing power. This study may help elucidate the mechanism of dispersion and develop structure-property relationships which could provide theoretical guidance in the design of molecular structure in the practical application.

Froth flotation is still an efficient technique for KCl production from low grade and complex systems containing various ions. In this work, the colloidal properties of one common collector, octadecylamine hydrochloride (ODA), in different saturated salt solutions at different temperature are investigated systematically. The results show that the turbidity of salt solutions increased substantially with the concentration of ODA increasing and the ODA colloidal particles aggregate seriously in the presence of MgCl2. Compared with ODA aqueous solutions, the surface activity and the critical aggregate concentration (CAC) of ODA became lower in saturated salt solutions. With the increase of MgCl2 percentage, the CAC values of ODA solution decreased gradually, while the CAC value of KCl-MgCl2 saturated solution was the lowest. The temperature has a great influence on the turbidity and surface activity of ODA aqueous solution, however, the effect is slight in saturated salt solutions. In addition, the salt solutions with MgCl2 result in lower contact angle on KCl crystal surface indicating that the adsorption of ODA molecules can be inhibited in the salt solutions with MgCl2.

The formation of promising oil-in-water microemulsion as detergent has been achieved by using linear medium chain fatty alcohols (C5-C8) as the oil phase, sodium dodecyl sulfate (SDS) and isomeric alcohol ethoxylate (IC13EO6) as a mixed surfactant, and 1-butanol as cosurfactant. Pseudoternary phase diagrams were constructed by addition of the water. The effect of the SDS to IC13EO6 mixing ratio on single phase microemulsion area size was systematically investigated. The structure transition of the microemulsion was measured by conductivity. The results show that with addition of the water, the structure of microemulsion transformed from water-in-oil, bicontinuous to oil-in-water. After diluted 500 times, the equilibrium contact angle and dynamic surface tension of the microemulsion were much lower than this for standard liquid detergent under the same condition indicating that the dilute microemulsion exhibited excellent spreading and wetting properties on hydrophobic surfaces. The detergency of the as-prepared microemulsions with different oil types was tested by Terg-O-Tometer in order to select optimum formulations from the infinite dilution zone. With optimum formulations, the detergency of microemulsion was higher than that of standard liquid detergents, because microemulsions exhibit strong solubilization ability on oil stain.

The coupling air organizations between supplying air jets and platform piston winds prevail on the platforms of the subway stations without platform screen doors (PSD) all over the world. The thermal comfort characteristics under the vent are studied in this paper. Firstly, the coupling mechanism of these two airflows is described based on the cross-flow theory. Secondly, Relative Warmth Index (RWI) is selected to evaluate human thermal comfort level with dynamic coupling airflows in the transitional areas. Calculated by the RWI theory model, it can be concluded that air velocities can be enhanced to compensate the supplying air temperature increasing without affecting human thermal sensations with RWI within 0-0.15. Thirdly, experimental studies are carried out and it can be seen that the average RWI values of vertical points under the vent increase from [−0.29, −0.03] in uncoupled conditions to [0.23, 0.14] in coupling conditions, leading to human thermal sensations greatly improved. The experimental RWI values of horizontal points move into the comfort zone a lot under coupling airflows conditions, compared with the uncoupled conditions. In conclusion, the coupling airflows of supplying air jets and cross-flows can improve the transitional thermal comfort and bring forward huge energy-saving potential in air-conditioning systems by allowing the supplying air temperature to be increased in transitional subway stations.

Majority of potash production around the word is still conducted through froth flotation, during the process of which the adsorption of collector on salt crystal surface is one of key points determining the accomplishment of flotation. In this work, the adsorption kinetics and isotherm models of one common collector, Octadecylamine Hydrochloride (ODA), on KCl surface in different saturated salt solutions at different temperature is studied for details. The results show that the adsorption equilibrium time is 4 h for ODA adsorbed on KCl surface in all systems at 25 °C. High temperature can increase the adsorption quantity, however, the presence of Mg 2+ will decrease it. This may be attributed to the property of ‘water structure maker’ for Mg 2+ in solutions. The pseudo-second-order model is appropriate to describe the adsorption kinetics for all studied systems. The adsorption isotherm of ODA on KCl surface is much more close to the Langmuir isotherm model than the Freundlich isotherm model. The adsorption process for all the systems need additional energy and the energy requirement increases with the temperature decreasing. In addition, the adsorption in all systems also presents an exothermic process. The randomness at the solid–solution interface becomes less in the KCl-MgCl 2 and KCl-NaCl-MgCl 2 saturated solutions than in KCl saturated solution. This work provides detailed information of adsorption process of ODA on KCl surface, which may constitute a step forwards in our understanding of froth flotation of KCl and help to improve the flotation recovery at low temperature.

Diethylamine, ethyl acetate and triethylamine are usually applied to synthesize an important flame retardant of vinylphosphorus, which has high ability to retard flames, low toxic content, and good washing durability. The isobaric VLE data of (diethylamine + triethylamine, diethylamine + ethyl acetate) and (ethyl acetate + trimethylamine) system were determined at 101.3 kPa for industrial separation. A minimum azeotrope was discovered at x = 0.8217 in the (ethyl acetate + trimethylamine) system. Therefore, a series of experiments were designed to investigate the effect of diethylamine on the (ethyl acetate + trimethylamine) system and the results indicated that the azeotrope can be eliminated when the liquid mole fraction of diethylamine is greater than 0.4687. Furthermore, molecular dynamics analysis through GROMACS software and Multiwfn software was also used to study the interaction of these three materials in this work. The results show that the weak interaction force around ethyl acetate decreases after adding diethylamine, which means that the van der Waals effect and the electrostatic effect of ethyl acetate become smaller. This may be the main reason why the azeotropic point of the (ethyl acetate + trimethylamine) system disappears.

Flocculation technology continues to be a useful method for wastewater treatment. In this work, a new type of covalently bound organic silicate aluminum hybrid coagulants (PAAP) with different Si/Al molar ratio and basicity were prepared by 3-aminopropyltriethoxysilane (APTES) as silicon source. The structure and morphology of the prepared coagulants were studied by FTIR, SEM and TEM. The effects of Si/Al molar ratio, basicity and dosage on the coagulation behaviors were investigated in detail. The results showed that PAAP0.1, 0.5 presented the large curl slice surface and the compact chain-net morphology, resulting in the best coagulation properties for simulation wastewater. Meanwhile, for coking wastewater, PAAP0.1,0.5 also showed better coagulation performance compared with conventional polyaluminum chloride (PAC). At the optimal dosage, the coagulation efficiencies for treatment of raw coking wastewater in terms of turbidity, UV254, DOC and COD were 82.05%, 12.09%, 9.34%, 24.16%, and that of biological treated coking wastewater were 97.84%, 37.72%, 29.97% and 63.39%, respectively. In addition, PAAP0.1,0.5 showed excellent strong storage stability over a long period of 12 months without sedimentation and gelatinization.

With the rapid growth of large-scale cities and the reinforcement of environmental concepts and sustainability, the sharing economy has received increasing attention. The maximum coverage location problem (MCLP), which is the basis of many sharing economy models, aims to cover more customers with a specified number of centers and radii. Many scholars have studied the MCLP Model from various angles and have achieved workload balance under maximum coverage by setting the upper limit of each center's workload. However, there has been little research involving the lower limit of the center. We propose a new MCLP model that includes a lower bound that would improve the quality of results. We also introduce the concept of “balance” that will reduce the imbalance of service levels at various locations. We call the proposed model balanced maximum coverage location problem (BMCLP). We test our model on the bike-sharing problem in a large Chinese city. Our results show the twin accomplishments of better maximal covering results and balanced service. We also show that our model is general enough to be applied to many sharing economy problems. In fact, for shared economic models, guaranteed services and balanced services are crucial for companies. Therefore, according to the basic theory of multiobjective optimization, a balanced maximal covering location problem (BMCLP) is proposed to determine a better design for maximal covering and balanced workload. Using the BMCLP Model successfully in a bike-sharing problem demonstrates that it is more general than the MCLP with demonstrated bounds.

Photocatalyst TiO2@g-CQDs were prepared by one-step sol-gel method using tetrabutyl titanate, anhydrous ethanol, hydrochloric acid and graphite carbon quantum dots and characterized by high-resolution transmission electron microscopy (HRTEM), Fourier transform infrared spectrum (FT-IR), X-ray diffraction (XRD), UV–visible diffuse reflectance spectra (UV-DRS) and X-ray photoelectron spectroscopy (XPS). The photocatalytic degradation of nonylphenol ethoxylate (NPE10O) by TiO2@g-CQDs and the degradation path of NPE10O by time-of-flight mass spectrometry (TOF-MS) were investigated. In addition, the photocatalytic mechanism of TiO2@g-CQDs was discussed in detail and the major active species were identified. The results showed that when the doping amount of g-CQDs is 5%, the amount of TiO2@g-CQDs is 0.1 g·L−1, the initial concentration of NPE10O is 50 mg·L−1, and the power of the light source is 500 W, the degradation efficiency of NPE10O can reach 100% at 60 min, which indicates TiO2@g-CQDs have excellent photocatalytic properties. TOF-MS showed that NPE10O was mainly degraded by nonylphenol polyethoxycarboxylate (NPExC) and carboxylated alkyl oxidation products of nonylphenol ethoxy (CAyPEC) intermediates during photocatalytic degradation. Trapping experiment of active species demonstrated that OH is the major active component for photocatalytic degradation of contaminant.

A series of butynediol-ethoxylate based polysiloxanes (PSi-EOs) with same composition but different lengths of siloxane backbone were designed and synthesized via hydrosilylation reaction. Their physicochemical properties and application performances have been discussed. With the increase of the length of siloxane backbone, the critical aggregation concentration (CAC) decreases and the surface tension at CAC (γ CAC ) increases, but the dynamic adsorption at the air/water interface has no significant change. Above the CAC, all of these three surfactants can self-assemble into spherical aggregates of 100 to 500 nm in aqueous solution. Moreover, the contact angle measurement on Paraffin film demonstrates that shorter siloxane backbone length of PSi-EO leads to lower contact angle and shows better spreading and wetting abilities. Using the foaming power test, PSi-EO with a longer siloxane backbone exhibits lower foaming and more effective anti-foaming properties in water.

Five different butynediol-ethoxylate modified polysiloxanes (PSi-EO) were designed and synthesized via two-step reactions: the preparation of low-hydrogen containing silicone oil (LPMHS) by acid-catalyzed polymerization and the following hydrosilylation reaction with 1,4-bis(2-hydroxyethoxy)-2-butyne. The chemical composition of each product was confirmed by FT-IR, (1)H NMR, and (29)Si NMR. The surface activities and aggregation behaviors of PSi-EO surfactants in aqueous solution were studied systematically using surface tension, dynamic light scattering (DLS), transmission electron microscopy (TEM), and contact-angle methodologies. Relatively low critical aggregation concentration (15-34 mg·L(-1)) and surface tension (∼25 mN·m(-1)) were measured for PSi-EO aqueous solution. The rate of surface tension reduction increased both with increasing PSi-EO concentration and with increases in the proportion of hydrophilic moieties within the synthesized compounds. Furthermore, DLS and TEM studies revealed that PSi-EO self-assembled in aqueous solution to form spherical aggregates. Contact-angle measurements conducted upon low-energy paraffin film surfaces demonstrated that PSi-EO exhibited efficient spreading at concentrations above the critical aggregation concentration.

In order to screen one suitable catalyst for magnetically stabilized fluidized bed (MSFB) reactor in the process of oxidative carbonylation of phenol to diphenyl carbonate (DPC), Pd/MnFe 2 O 4 catalysts were chosen, then prepared and characterized by XRD, H 2 -TPR, O 2 -TPD and VSM. Compared to the other metal ion doped spinel ferrite catalysts, the catalytic activity of Pd/10% PbO–MnFe 2 O 4 was much higher, which the single pass yield of DPC reached 33.12% with selectivity above 99%, and TOF (turnover frequency) reached 70.56 molDPC·(molPd h) −1 . The result showed that the formation of the ferrite oxygen-deficient and ion transference in the ferrites was in favor of the catalytic activity. When the support MnFe 2 O 4 was calcinated at 500 °C, the saturation magnetization of the obtained catalyst Pd/10% PbO–MnFe 2 O 4 came up to 37.81 Am 2 kg −1 . With good magnetic property and brilliant catalytic activity the catalyst Pd/PbO–MnFe 2 O 4 may suite for industrial experiments in MSFB reactor in future.

The perovskite MgTiO 3 catalyst was prepared by the sol–gel method and characterized by X-ray diffraction (XRD), temperature-programmed desorption of CO 2 (CO 2 -TPD) and energy dispersive spectroscopy (EDS). The catalytic behavior was also investigated for the urea alcoholysis to propylene carbonate (PC). It was found that the preparation conditions of MgTiO 3 , including calcination temperature, calcination time and Mg/Ti molar ratio, affected the aggregation of MgO on the surface of MgTiO 3 . Aggregated MgO could promote a synergistic effect with MgTiO 3 to change the basic performances on the surface, which resulted in the activity difference. When MgTiO 3 was prepared at calcination temperature of 700 °C, the calcined time of 3 h and the Mg/Ti molar ratio of 1.0, the synergistic effect was the strongest, which led to the highest activity. The yield and the selectivity of PC were up to 93.5% and 99.0%, respectively. An increased number of reuse of the catalyst, resulted in a loss of MgO from the catalyst surface, thereby reducing the overall catalytic activity.

The removal of slimes (water-insoluble minerals) from high slime-containing potash ores from Qinghai Province, PRC, was investigated using flotation. A higher slime flotation recovery was obtained when a surfactant (polyoxyethylene fatty acid ester)–kerosene water emulsion was used as the collector. The stabilities of the kerosene/aqueous emulsions in water and in KCl saturated solution were tested to understand the mechanism of the desliming flotation process. The results showed that the phase separation of the emulsion was pronounced at low surfactant concentration. Microscopic observation of the emulsion microstructure indicated that the droplets were spherical with the exception of samples with low surfactant concentration and that the droplet size increased with decreasing surfactant concentration. The emulsion droplets in the KCl saturated solution were smaller than those in pure water. Additionally, the emulsion was easier to stabilize in KCl because of the higher surface activity in KCl saturated solution; therefore, this emulsion can be used as a collector in desliming flotation.

Thermosensitive SiO2 nanoparticles were prepared with graft-on poly(ethylene glycol) methyl ether methacrylate (POEGMA, Mn ∼ 300 or 500 g mol−1) via atom transfer radical polymerization with activators generated through electron transfer (AGET ATRP). CuBr2/PMDETA and ascorbic acid (AA) were employed as the catalyst and reducing agent respectively in the fabrication process. The structure and surface composition of our hybrid materials were analyzed using Fourier Transform Infrared (FTIR) spectroscopy and X-ray Photoelectron Spectroscopy (XPS) in detail. The results of Thermogravimetric Analysis (TGA) show that AGET-ATRP could provide a higher surface grafting density to get more pronounced thermosensitive properties. The morphology of our hybrid SiO2 nanoparticles was characterized by Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM). measurements of turbidity, Dynamic Light Scattering (DLS), and phase transfer were conducted to investigate the thermal responses of the hybrid material. In addition, Pickering emulsions were prepared using such hybrid SiO2-POEGMA as an emulsifier. Moreover, its fast de-emulsification above a lower critical solution temperature (LCST) may be exploited for the efficient separation and recycling of catalysts in future.

A trisiloxane surfactant was synthesized with grafting butynediol ethoxylate onto hydrophobic heptamethyltrisiloxane. The structural analysis of this surfactant was done by 1H, 13C and 29Si NMR. The surface activity, adsorption kinetics, aggregation behaviors in aqueous solutions, and dynamic spreading performances of this siloxane amphiphile were investigated by surface tension, transmission electron microscopy (TEM), dynamic light scattering (DLS) and contact angle techniques at 298 K. The surface tension of this trisiloxane surfactant measured at critical aggregate concentration (CAC) was observed to be significantly lower than that of acetylenic diol based surfactants. Adsorption model for this amphiphile is diffusion-controlled model. Aggregates of this nonionic surfactant formed in aqueous solutions could be assigned as spherical assemblies as suggested by analysis using TEM and DLS. The spreading performances on low-energy Teflon film and paraffin film interface was studied by the contact angle measurement with sessile drop method and proved that it has a potential as spreading agents in industry.

Rheological properties of biological surfactant sodium deoxycholate (NaDC) in the presence of two amino acids ( l -Lys and l -Arg) and two halide salts (NaCl and NaBr) have been investigated systematically at 20 °C and pH = 6.864. The gel-to-sol transition behavior induced by the addition of amino acids can be observed. It is found that the viscoelasticity of the hydrogels of 50 mmol L −1 NaDC decreased when l -Lysine ( l -Lys) or l -Arginine ( l -Arg) was added in the system. However, the addition of halide salts NaCl or NaBr in the above system resulted in an opposite trend. In view of these phenomena, a conclusion was given that l -Lys and l -Arg amino acids can destroy the network structure of the hydrogels while NaCl and NaBr can strengthen it. Moreover, it is found that the viscoelasticity of the l -Lys-containing hydrogel is higher than that of l -Arg-containing hydrogel at the same condition, on the other hand, the viscoelasticity of NaCl-containing hydrogel is higher than that of NaBr-containing hydrogel at the same concentration, indicating that NaCl performs better in strengthening the network structure of the hydrogels than NaBr. Furthermore, thixotropic experiments have also been done and revealed that the NaDC hydrogels prepared in this work possessed excellent thixotropic properties, which have potential applications in the field of as smart materials for drug controlled release materials.

Three novel surface active room-temperature ionic liquids (RT-ILs), Si(3)N-CA(n)(n = 1, 2, 3), were synthesized, in which trisiloxanes were introduced as hydrophobic group to reduce the ionic liquids’ melting points. Their surface activity and aggregation behavior in aqueous solution were systematically investigated through measurement of surface tension, conductivity, dynamic light scattering (DLS), transmission electron microscopy (TEM), and cyro-transmission electron microscopy (Cyro-TEM). The surface tension of the aqueous trisiloxane RT-ILs solutions measured at the critical aggregate concentration (CAC) were observed to be about 20 mN m−1, much lower than those of traditional N-alkyl ionic liquids. With a combination of DLS data and TEM measurements, formations of multilamellar vesicles in trisiloxane RT-ILs solutions appear to occur at a concentration above the CAC.

Yolk–shell silica spheres consisting of a core and an outer shell were prepared by a one-step method using a new class of eco-friendly templates, trisiloxane-tailed surface active ionic liquids. The effects of pH, calcination, and template concentration were investigated in detail. Our results showed that yolk–shell silica spheres could be obtained only in alkaline conditions when using trisiloxane-tailed ionic liquids as templates. The particle diameter, core diameter, dimension of void space, and shell thickness, which we measured by transmission electron microscopy and nitrogen adsorption–desorption techniques, could be tuned by precisely varying the template concentration. The organosilicon component of the ionic liquid template contributes to the reaction during the formation of yolk–shell nanostructures, which leads to a firm silica sphere skeleton resulting in essentially identical morphology and void structure before and after calcination. This investigation provides a convenient approach to fabricate yolk–shell silica spheres, which may expand the application of organosilicon ionic liquids in the field of nanomaterials and could be expected to generate tailor-made yolk–shell silica with functionality in both the core and shell.

Three amphiphilic trisiloxane room-temperature ionic liquids, [(Si(3)N(2)-AC(2), Si(3)N(2)-PC(2), Si(3)N(2)-BC(2))], were designed and synthesized. Their surface activity and aggregation behavior in aqueous solution were systematically investigated through measurements of surface tension, conductivity, and transmission electron microscopy (TEM). Surface activity measurements indicate that the trisiloxane ionic liquids can significantly reduce the surface tension of water, as shown by the γcac values of about 20 mN/m. Aggregation behavior studies reveal that the aggregates formed in Si(3)N(2)-AC(2) and Si(3)N(2)-PC(2) solutions are observed to be small spherical aggregates, while those formed in Si(3)N(2)-BC(2) solutions are found to be large necklace-like aggregates.

A basic catalyst for urea alcoholysis to propylene carbonate (PC) was prepared from a solid waste, phosphate tailing (PT), and was characterized by TGA, BET, XRD, CO2-TPD and EDS. The PC yield was found to be related to the total content of Mg, Ca and P elements and strong basic sites on the catalyst surface. PT-800-4 possessed the highest total content, which led to the formation of strong basic sites and the highest PC yield of 81.8% with the 95.6% selectivity at the catalyst amount of 0.22 wt% (based on urea), and could be reused at least 5 times.

The aggregation behavior of two trisiloxane-tailed surface active ionic liquids (ILs), 1-methyl-3- trisiloxaneimidazolium chloride ([Si(3)Mim]Cl) and trisiloxanepyridinium chloride ([Si(3)Py]Cl), in aqueous solution was investigated by the measurement of surface tension, electrical conductivity, transmission electron microscopy (TEM), dynamic light scattering (DLS), and X-ray diffraction (XRD). The surface tension measurement showed the critical aggregation concentration (cac) of [Si(3)Mim]Cl and [Si(3)Py]Cl is 15.5 and 24.8 mmol l−1 respectively, and the corresponding surface tension at cac (γcac) is 23.8 and 23.0 mN m−1, respectively. The phenomenon was mainly ascribed to the branched trisiloxane hydrophobic moieties and these results demonstrated that the surface activity of these trisiloxane-tailed ILs was somewhat superior to that of conventional ILs. The vesicular-like structure of the aggregates was observed by TEM while DLS provided the diameter distribution of these aggregates. In addition, a probable two-layered arrangement of molecules in aggregates for the two ILs in aqueous solution was proposed based upon the results of XRD studies. This investigation may contribute to expand understanding of trisiloxane-tailed ILs. Furthermore, high thermal stability of such compounds may improve their potential applications in the fields of colloids and interfaces science.

The magnetic perovskite-supported palladium catalysts Pd/La 1− x Pb x MnO 3 ( x = 0.2−0.7) were prepared and used for the oxidative carbonylation of phenol to diphenyl carbonate. The synthesized catalysts were characterized by the X-ray diffraction (XRD), surface area measurement BET, vibration sample magnetometer (VSM) and temperature-programmed reduction (TPR). The experimental results demonstrated that the magnetic Pd/La 1− x Pb x MnO 3 ( x = 0.4−0.5) obtain relative better catalytic activity. It can be explained by higher concentration of oxygen vacancies, larger amount and better mobility of lattice oxygen of their support. Furthermore, these samples possess sufficient saturated magnetization. Thus, Pd/La 1− x Pb x MnO 3 ( x = 0.4−0.5) may be suitable for operation in the magnetically stabilized bed reactor.

To address the limitations of batch organic-aqueous biphasic catalysis, we develop a conceptually novel method termed Flow Pickering Emulsion, or FPE, to process biphasic reactions in a continuous flow fashion. This method involves the compartmentalization of bulk water into micron-sized droplets based on a water-in-oil Pickering emulsion, which are packed into a column reactor. The compartmentalized water droplets can confine water-soluble catalysts, thus "immobilizing" the catalyst in the column reactor, while the interstices between the droplets allow the organic (oil) phase to flow. Key fundamental principles underpinning this method such as the oil phase flow behavior, the stability of compartmentalized droplets and the confinement capability of these droplets toward water-soluble catalysts are experimentally and theoretically investigated. As a proof of this concept, case studies including a sulfuric acid-catalyzed addition reaction, a heteropolyacid-catalyzed ring opening reaction and an enzyme-catalyzed chiral reaction demonstrate the generality and versatility of the FPE method. Impressively, in addition to the excellent durability, the developed FPE reactions exhibit up to 10-fold reaction efficiency enhancement in comparison to the existing batch reactions, indicating a unique flow interface catalysis effect. This study opens up a new avenue to allow conventional biphasic catalysis reactions to access more sustainable and efficient flow chemistry using an innovative liquid-liquid interface protocol.