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The hydrophobic nature of an extractant is particularly critical in the treatment of wastewater. Considering that dicationic ionic liquids (DILs) are likely to be more hydrophobic, a comparative study of the separation of phenol from waters using [NTf 2 ]– based monocationic ionic liquids (MILs) and DILs is carried out both from experimental and theoretical analysis perspectives. Experimental results revealed that DILs exhibited superior extraction ability compared to MILs, with extraction efficiencies of 93.7% and 97.4% using [BMIM][NTf 2 ] and [C 6 (MIM) 2 ][NTf 2 ] 2 as extractants, respectively. The microscopic examination through theoretical calculations elucidated the higher hydrophobicity and extraction efficiency of DILs over MILs. The results indicated that the DIL showed stronger hydrophobicity than the MIL because the hydrogen bond strength between the DIL and water was lower than that of the MIL. Although the hydrogen bond strength between the DIL and phenol was lower than that of the MIL, the stronger van der Waals forces existed between DIL and phenol, so DIL was more efficient in extracting phenol. In addition, the experimental parameters were optimized to provide basic data for application, such as mass ratio of ILs to water, extraction time and temperature, pH, and initial phenol content. Finally, the DILs were recovered using rotary evaporation apparatus, and the results demonstrated that DILs had good recovery and reuse performance. In brief, this work could provide an effective method for the treatment of phenol-containing wastewater. And the revelation of molecular mechanism is expected to positively impact the design of high-performance task-specific ILs. [Display omitted] • Hydrophobic DILs are proposed for the separation of phenols from aqueous solutions. • Stronger hydrophobicity of DILs than that of MIL is revealed from molecular insights. • Both high extraction ability and low solubility in water are achieved by DILs. • Analysis of interaction energies between the phenol and water with ILs. [ABSTRACT FROM AUTHOR]

Designing eco-friendly deep eutectic solvents (DESs) for industrial applications relies on choosing environmentally sustainable hydrogen bond acceptors (HBAs) and donors (HBDs). The study of the weak interactions between these components are essential to assess the performance of DESs in extraction and separation processes. However, there remains a dearth of knowledge regarding the molecular mechanisms influencing the structure-activity relationships in DES systems. This work introduces a new multiscale simulation analytical approach based on the mechanism revealed by the HBA-HBD interaction sites. Quantum chemical (QC) calculations were used to calculate the binding energy, weak interaction type and charge transfer analysis of each site. And the obtained microscopic mechanism was subsequently applied to a real macroscopic phenol-toluene separation system for cross-validation. Molecular dynamics (MD) simulations further illuminate the impact of HBA structure on the extraction process at the molecular level, corroborating QC calculation results. Notably, this underscores the significance of HBAs structure interactions with phenol. The multiple interaction sites of the L-carnitine structure with phenol validate the use of a lower L-carnitine dosage compared to ChCl and betaine in the liquid-liquid extraction (LLE) experiments. These results extend to advancing understanding of eco-friendly DESs, providing a basis for the development of sustainable and efficient extraction processes. [Display omitted] • Two natural, non-toxic compounds betaine and L-carnitine were chosen as HBAs. • The relationship between the structure of HBAs and their ability to segregate was elucidated by focusing on the interaction sites of HBAs with phenol. • QC calculations were used to compare the microscopic mechanisms of interaction between interaction sites in each system. • The microscopic mechanism was applied to the macroscopic system for cross-checking and mutual verification. [ABSTRACT FROM AUTHOR]

Raw materials and synthesis strategies have great influence on the morphologies and optical properties of materials. In this study, ultrasonic synthesis of controllable thin sheet-like BiPO 4 with an excessive visible-light response was synthesized, using Bi-based metal-organic frameworks (CAU-17) and ionic liquid [Omim]H 2 PO 4 as raw materials. Compared with BiPO 4 -H (hydrothermal, solid rod shape) synthesized using inorganic salt, BiPO 4 -A (agitation, thin rod-like) and BiPO 4 -U (ultrasonic, thin sheet-like) have better visible-light absorption capacity and narrower band gap. Under visible-light, they could degrade 27.7 % (BiPO 4 -H), 73.0 % (BiPO 4 -A), and 76.3 % (BiPO 4 -U) tetracycline hydrochloride at 30 min, respectively. The speedy charge transfer at the photogenerated carrier interface, large specific surface areas, and improved light adsorption greatly enhance the photocatalytic performance. Cyclic experiments exhibit that the material has good photostability and repeatability. Finally, the feasible degradation mechanism of the material was proposed via a capture experiment. This paper provides a new technique for synthesizing BiPO 4 or other photocatalysts, which can be used for high-efficiency wastewater purification under visible-light. [Display omitted] • A novel ultrasonic synthesis method for BiPO 4 with excellent visible-light response is presented. • [Bi-MOF(CAU-17)] and [Omim]H 2 PO 4 were used as raw materials instead of traditional inorganic salts. • The linear average photocatalytic rate of BiPO 4 -U is 16.1 times of BiPO 4 -H synthesized by traditional methods. • Possible photocatalytic mechanism was proposed based on photo-electrochemical characterization and free radical tests. [ABSTRACT FROM AUTHOR]

To develop a greener method to separate phenols from oils, four kinds of halogen-free zwitterions, including 1-(propyl-3-sulfonate)-triethylaminium (TEA-PS), 1-(propyl-3-sulfonate)-tripropylaminium (TPA-PS), 1-(butyl-4-sulfonate)-triethylaminium (TEA-BS) and 1-(butyl-4-sulfonate)-tripropylaminium (TPA-BS), were designed and synthesized to separate phenols from model oils via forming deep eutectic solvents (DESs) based on the formation of hydrogen bonding between OH group on phenol and the oxygen atom on SO 3 − group of the zwitterions. The effects of time, temperature, dosage of zwitterions, initial phenol content, and structure of zwitterions were investigated. The results show that the extraction process can reach equilibrium within 2 min and the extraction efficiency is not sensitive to temperature. The zwitterions separate well phenol from model oils at room temperature, and the minimum phenol contents follow the order: TEA-PS > TPA-PS > TEA-BS > TPA-BS. The minimum phenol content and the maximum extraction efficiency at 25 °C can reach 4.8 g dm −3 and 98.6%, respectively, by using TPA-BS. All the maximum extraction efficiency can be obtained with n zwitterions : n phenol of less than 0.4, which greatly reduces the dosages of extractants. Importantly, these zwitterions can avoid the introduction of halide ion, which can seriously corrode the process equipment. All these zwitterions can be easily regenerated by an anti-solvent method without an obvious mass loss and a decrease in phenol extraction efficiency. Lastly, the extraction mechanism was studied with FT-IR and the freezing points of DESs indicate that the DESs are formed through hydrogen bonding. [ABSTRACT FROM AUTHOR]

The separation of aromatics from aliphatics is challenging and energy-consuming because of the very close boiling points among these compounds and the possibility of forming azeotropes. In this work, we designed two imidazolium-based dicationic ionic liquids, [C5(MIM)2][NTf2]2 (DIL1) and [C6(MIM)2][NTf2]2 (DIL2), and found that they could highly efficiently extract aromatics from aliphatics. Three different aromatic and aliphatic mixtures, toluene/n-heptane, benzene/n-hexane and benzene/cyclohexane, were used to investigate the universality of DILs. The extractive performance of both DILs was compared with those of other promising ILs and sulfolane. The mixtures of toluene and aliphatics with different chain lengths were also investigated. The results showed that the two DILs had relatively high selectivity and distribution coefficients for different aromatic and aliphatic mixtures. At 30 °C, the highest values of selectivity and distribution coefficient for toluene/n-heptane, benzene/n-hexane and benzene/cyclohexane systems were 50.4, 64.8, and 24.9 and 1.44, 2.44, and 2.25, respectively. The performance of DILs at 30 °C was better than that at 40 °C. Besides, a higher selectivity could be obtained when toluene is used with a longer chain aliphatic, such as a selectivity of 61.4 could be obtained when the aliphatic was n-nonane. The study of the physicochemical properties of DILs showed that they were more stable than the previous ones. In a word, the two DILs were evaluated as potential solvents for the separation of aromatics from aliphatics. [ABSTRACT FROM AUTHOR]

Four kinds of dual-functionalized ionic liquids (DFILs, [Et 2 NEmim][Cl] 2 , [Et 2 NEmmor][Cl] 2 , [Et 2 NEmpyr][Cl] 2 and [Et 2 NEmpic][Cl] 2 ) were synthesized and used to efficiently separate phenolic compounds from model oils. The effects of stirring time, temperature, mole ratio of DFIL to phenol and initial phenol content on the separation were investigated. The results indicate that at a DFIL:phenol mole ratio of 0.3, the content of phenol in the oil phase can reach the minimum value and the extraction efficiency of phenol is more than 96%. The minimum phenol content in the oil phase and the best phenol extraction efficiency were 5.9 g/m 3 and 98.5%, respectively, when [Et 2 NEmpyr][Cl] 2 was used. Compared with traditional ionic liquids, these DFILs not only reduce the dosage of extraction agents but also greatly decrease the content of Cl − in the oil phase due to the double anion in the DFILs. The DFILs can be reused for 4 cycles without losses in phenol extraction efficiency and masses of the DFILs. The separation mechanism of extraction was studied using FT-IR. The result indicates that the two anions Cl − on DFILs can form a hydrogen bond with phenol. [ABSTRACT FROM AUTHOR]

The separation of phenolic compounds from oil mixtures is widely used in the chemical industry. In this research, we found that two types of environmentally benign quaternary ammonium-based zwitterions, betaine and l -carnitine, could be used as new extractants for the separation of phenol from model oils by forming deep eutectic solvents (DESs). The effects of extraction time, temperature, mole ratio of zwitterion to phenol and initial phenol content on the efficiency of phenol separation were investigated. The results indicated that betaine and l -carnitine could form DESs with phenol, and the DESs were insoluble in model oils. Phenol in model oils could be extracted with extraction efficiencies up to 94.6% at an l -carnitine:phenol mole ratio of 0.4 (an l -carnitine:phenol mass ratio of 0.68) and 298.2 K. Phenol in DES could be recovered using an anti-solvent, and betaine and l -carnitine could be regenerated and reused for 4 cycles without obvious decreases in extraction efficiency and extractant mass, and they were not changed in their structures after reuse. The separation mechanism was investigated using FT-IR, which showed that betaine and l -carnitine formed DESs with phenol through hydrogen bonding. [ABSTRACT FROM AUTHOR]

Phenols are important materials for the organic chemical industry. They mainly come from coal liquefaction oil, coal tar, petroleum and biomass pyrolysis oil, making the separation of phenols from oil mixtures of great commercial value. Two zwitterionic alkaloids, betaine and L-carnitine, biodegradable and environmentally benign ionic compounds, can efficiently separate phenols from oils by forming deep eutectic solvents (DESs). In this work, the phase equilibria of two ternary systems of toluene + phenol + betaine and toluene + phenol + L-carnitine were measured at 25.0 °C, 45.0 °C and 65.0 °C under atmospheric pressure. The phase behaviors of the two ternary systems were studied, which indicated that there were three kinds of phase regions: liquid, liquid-liquid, and liquid-liquid-solid. The separation of phenol from oil mixtures occurs at the latter two phase regions. Effects of temperature, zwitterionic alkaloid type and its dosage on the phase equilibrium were investigated. With decreasing temperature, the distribution and selectivity coefficients increase. L-carnitine shows better performance in separating phenol from oils via forming DES than betaine. [ABSTRACT FROM AUTHOR]

[Display omitted] • The roles of cresols played in DESs are clarified by experiments. • The binding interactions of DESs are revealed from theoretical perspectives. • The intermolecular interaction regions are visualized by reduced density gradient (RDG). • The energy decomposition analysis (EDA) confirms that the electrostatic effect is dominant. • The atoms in molecules analysis (AIM) describes the sites and types of weak interactions between DESs at the atomic level. To provide some guidance for the selective separation of cresol isomers from oils, the effect of structure on the physicochemical properties of deep eutectic solvents (DESs) formed by choline chloride (ChCl) and cresol isomers were studied. In this study, DESs with different mole ratios of cresols to ChCl (1.68 to 9.00) were prepared. The physicochemical properties (viscosity and density) of DESs, which were related to the separation process, were measured at different temperatures. The results indicated that the density and viscosity were closely related to the structure of cresols, temperature, and mole ratios of cresols to ChCl. Interestingly, when the mole ratio of cresols to ChCl was large enough, such as > 5.00, the density and viscosity got correspondingly closer to that of the pure cresols. This meant that cresols could not only serve as hydrogen bond donors to form DESs but also act as a solvent to dilute DESs. Finally, density functional theory (DFT) was used to reveal the microscopic properties and binding interactions of DESs. The most stable conformations, corresponding interaction energies and hydrogen bond length of DESs were obtained from the Gaussian 16 software, and Multiwfn 3.8 program was used to perform wave function analysis of the system. The results showed that the interaction between ChCl and cresol isomers decreased in the order o -cresol, m -cresol, and p -cresol, and the hydrogen bond dominated the interaction. The results at the molecular/atomic level further verified the experiment results, and a better understanding of the structural characteristics and intermolecular interactions of DESs could provide opportunities for the application of DESs. [ABSTRACT FROM AUTHOR]

Investigation of the mechanism of oxygen vacancy-regulated photoelectrochemical sensors for highly sensitive and selective determination of biomolecules containing electron-donating groups is an innovative research field. In this study, oxygen vacancy-regulated TiO 2 nanotube arrays (Ov-TNTs) with high photoelectrochemical activity were synthesized and applied to defect tetracycline hydrochloride (TC). The synergistic effect of oxygen vacancies and Ti3+ droves Ov-TNTs with a narrow energy band to generate more photogenerated carriers under irradiation. The photocurrent response of the oxygen vacancy-regulated photoelectrochemical sensor decreased with increasing TC concentration, which could be mainly attributed to adsorption of TC, which consumed part of the oxygen vacancies on the surface of Ov-TNTs. This system had excellent linearity in the range of 0.1–1000 nM with a detection limit of 0.33 nM (S/N = 3). In addition, the sensor was highly selective for TC determination due to the mutual electrostatic interaction between negatively charged TC-containing electron-donating groups (-NH 2 and -OH) and positively charged Ov-TNTs. This study provided a foundation for developing an oxygen vacancy-regulated adsorptive photoelectrochemical sensor. • The introduction of oxygen vacancies drives TNTs with narrow energy band to generate more photogenerated carriers. • Oxygen vacancies can be used as electron traps for preferential adsorption of TC molecules with electron-donating groups. • The photoelectrochemical sensor exhibits superior sensitivity and selectivity for TC detection. • The mechanism investigation shows that the adsorption of TC on the surface of Ov-TNTs decreases the oxygen vacancies and Ti3 + concentration, resulting in the gradual recovery of photocurrent to pure TNTs. [ABSTRACT FROM AUTHOR]

In this work, the typical honeycomb-nanoparticle heterostructure with honeycomb TiO 2 nanotube arrays (HTNTs) as light harvesting unit and Bi 2 MoO 6 nanoparticles (BMO) as recognition unit was prepared for highly sensitive and selective nano-enzymatic photoelectrochemical L-cysteine biosensor. [Display omitted] • The typical honeycomb-nanoparticle heterostructure between HTNTs and BMO improves the light harvesting behavior and the separation efficiency of the electron-hole pairs. • BMO nanoparticles fully dispersed on HTNTs with large specific surface area provides more sites for Cyst recognition. • Cyst can be specifically recognized through the Bi-S bonds. • The PEC enzyme-free biosensor shows good performance for Cyst with low detection limit and wide linear range. Improving light harvesting behavior and recognition sites of sensor is an effective way to achieve highly sensitive and selective detection of nano-enzymatic photoelectrochemical (PEC) L-cysteine (Cyst). In this work, the Bi 2 MoO 6 -TiO 2 composite (BMO-HTNTs) with honeycomb TiO 2 nanotube arrays (HTNTs) as light harvesting unit and Bi 2 MoO 6 nanoparticles (BMO) as recognition unit was prepared. The typical honeycomb-nanoparticle heterostructure between HTNTs and BMO improves the separation efficiency of the electron-hole pairs. Moreover, BMO nanoparticles fully dispersed on HTNTs with large specific surface area provide more sites for Cyst recognition. The composite exhibited the enhanced light absorption and higher photocurrent density at 0.2 V (vs. Ag/AgCl), which was 4 times than that of HTNTs under simulated light. Ingeniously, Cyst can not only be specifically recognized through the Bi-S bonds but also act as electron donor to scavenge the photogenerated holes of BMO-HTNTs, resulting in the increase of PEC responses. The PEC sensor showed superior analytical performance for Cyst detection with two linear regression equations in the range of 500 nM to 500 μM and a detection limit of 150 nM. The results of the enzyme-free sensor on practical urine and serum samples demonstrated its promising application in biological monitoring. [ABSTRACT FROM AUTHOR]

Metal-organic frameworks (MOFs) have attracted great interest in the field of photocatalysis because of their adjustable porous structure and semiconductor properties. In this research, a new type of MIL-88B(Fe)/Bi 2 WO 6 was successfully prepared by growing MIL-88B(Fe) on the surface of flower-like Bi 2 WO 6 spheres. The structures of materials were characterized through XRD, BET, XPS, SEM, TEM, EDX and FT-IR. 7-MIL-88B(Fe)/Bi 2 WO 6 exhibits the highest photocatalytic performance with a degradation rate of 96.4% within 90 min under visible light irradiation. Compared with pure Bi 2 WO 6 or MIL-88B(Fe), 7-MIL-88B(Fe)/Bi 2 WO 6 exhibits the largest specific surface area to provide more active sites. Additionally, the ·O 2 - and ·OH played dominant roles during the photocatalytic degradation process based on trapping and ESR tests. Through cyclic experiments, MIL-88B(Fe)/Bi 2 WO 6 composites show good stability and degradation efficiency, indicating its application potential in the environmental field. [Display omitted] [ABSTRACT FROM AUTHOR]

Non-noble metal for surface plasmon resonance (SPR)-induced nano-enzymatic photoelectrochemical (PEC) biosensors is a promising method for broad applications. Non-noble metal bismuth (Bi) is gradually being valued for their properties such as non-toxicity, abundant reserves, and good catalysis. Meanwhile, metallic Bi nanoparticles (NPs) have superior SPR properties similar to that of noble metal. Therefore, a non-noble metal Bi/BiVO4 photoanode based on SPR was designed for the PEC detection of H2O2 in this work. The synergistic effect of BiVO4 with suitable band gap (2.5 eV) and Bi NPs with superior SPR effectively reduces the recombination of photogenerated electrons and holes, which significantly improves the PEC activity of Bi/BiVO4 electrode at low voltage. The in situ Bi/BiVO4/FTO photoelectrode not only exhibits a more comprehensive linear range of 0.005–2.6 mM with a lower detection limit of 2.0 μM but also possesses excellent selectivity for the determination of H2O2 because the coexisting substances are difficult to be oxidized at 0 V bias voltage. The investigation of Bi/BiVO4-based sensor has contributed to the development of non-noble metal for SPR-induced PEC biosensors. [ABSTRACT FROM AUTHOR]

Bismuth (Bi) is a particular element with many distinctive properties such as low toxicity or nontoxicity, high specific gravity, photoluminescence, photoelectronic and photovoltaic effects, strong oxidation ability, water insolubility, etc. These distinctive properties help to boost various applications of Bi. The recent decades have witnessed a dramatic increase in the application research of Bi‐based materials, especially on photocatalysis. This paper begins with an introduction to the history of Bi, followed by a summary of its distinctive properties, and then provides a comprehensive overview of its applications in photocatalysis, sensing, medicine, and diagnosis and treatments, with a particular focus on near‐infrared photocatalysis, flexible wearable sensor, in vivo detection and therapeutics. Finally, the main challenges and development prospects of the Bi‐based materials are introduced. With the development trends of Bi research discussed, this paper is aimed at improving the knowledge of Bi and arising the research interest of Bi in the hope of extending the applications of Bi. [ABSTRACT FROM AUTHOR]

• Hydrophobic imidazolium-based dicationic ionic liquids (DILs) can dissolve small-content water. • A small content of water in the DILs can decrease their viscosity greatly. • The DIL with small-content water can efficiently extract aromatics from aliphatics. • Both high distribution coefficient and high selectivity by the DILs + water are achieved. • The extraction process using the DILs + water is in accord with the concept of green chemistry. The extraction of aromatics from aliphatics with both high distribution coefficient (D) and high selectivity (S) is a challenge in the industry. Hydrophobic dicationic ionic liquids (DILs) were demonstrated as efficient extractants with both high D and high S. However, the high viscosity of the DILs may influence their application. In this work, we found that a hydrophobic DIL ([C 5 (MIM) 2 ][NTf 2 ] 2) could dissolve a small amount of water with a solubility of 2.24 wt% at 303.15 K. The viscosity and density of the DIL with different contents of water were investigated from 293.15 K to 333.15 K. A small amount of water in the DIL could decrease its viscosity greatly, while had little effect on its density. The effect of water content in the DIL on the extraction performance was studied, and it was found that both D and S remained high when a small amount of water dissolved in the DIL. The highest selectivity and distribution coefficient for toluene were 45.7, 0.86 (water content: 1.10 wt%) and 41.5, 0.75 (water content: 1.59 wt%), respectively. With increasing the carbon chain of aliphatics, both D tol and D ali decreased, but S increased in the presence of water. All the results indicated that the DIL with a small amount of water not only had high D and S simultaneously, but also enhanced the extraction process. Importantly, the use of water in the extraction process accords with the concept of green chemistry. [ABSTRACT FROM AUTHOR]

Highly efficient separation of aromatics and aliphatics mixtures is important in the chemical industry. In this work, we designed several new composite extractants formed by a dicationic ionic liquid (DIL, [C 5 (MIM) 2 ][NTf 2 ] 2) and solvents, which have low viscosity and could enhance the mass transfer in the extraction process. We systematically investigated and compared the viscosity and separation performance between the pure DIL and composite extractants. The results indicated that the type of solvents and their content in composite extractants had a big influence on separation performance. Among the composite extractants, DIL-TTEG (tetraethylene glycol) showed the best extraction performance. The highest selectivity (S) and distribution (D tol) for toluene are 38.8 and 1.05, respectively, at a mass fraction of toluene = 0.1, m DIL : m TTEG = 10:1, and T = 30 °C. At these conditions, compared to the DIL, the viscosity of DIL-TTEG decreases 43.0%, while, the S and D tol still keep high values. Notably, the S and D tol are 1.89 and 2.56 times of pure TTEG. The best performance for benzene/ n -hexane and benzene/cyclohexane systems are S : 46.8 and 23.7, D : 1.92 and 1.78, respectively, at 0.1 mass fraction of benzene. The results show that DIL-TTEG not only has relatively low viscosity, but also shows good extraction performance. Furthermore, it can be regenerated simply by distillation. Given these properties, DIL-TTEG is a promising composite extractant to selective extraction aromatics from aliphatics in the industry. • Dicationic IL-solvent composite extractants were designed to separate aromatics from aliphatics. • Types of solvent and its ratio have a big influence on separation performance. • Highest distribution coefficient and selectivity for toluene are 1.05 and 38.7, respectively. • Satisfying extraction performance and adequate viscosity can be achieved simultaneously. • DIL-TTEG can maintain similar level of selectivity to DIL when oils contain cycloalkanes. [ABSTRACT FROM AUTHOR]

In2S3/BiOI composites were synthesized at room temperature which significantly improved the photocatalytic degradation of tetracycline hydrochloride (TC) under visible light irradiation. Structure and morphology characterization techniques have been performed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction measurements (XRD) and X-ray photoelectron spectra (XPS). The separation ability of photogenerated carriers is enhanced due to the formation of heterojunctions of the composites. The best performance is obtained when the content of In2S3 is 7 wt%. Compared with In2S3 and BiOI alone, 7-In2S3/BiOI has the highest specific surface area and can provide more active sites. Based on the photo-electrochemical characterization and free radical tests, a photocatalytic mechanism of In2S3/BiOI composites in the presence of superoxide radicals (˙O2−) and holes (h+) is reasonably proposed. [ABSTRACT FROM AUTHOR]

BiOCl has been identified to be a promising semiconductor material with exceptional performance for photodegradation of organic pollutants. In this work, a feasible strategy to synthesize octagon‐like BiOCl nanoflakes (G‐BiOCl NFs) with novel morphology was developed by one‐step solvothermal reaction in ethylene glycol/water solution with the addition of glutamate acid. The obtained G‐BiOCl NFs with large surface areas and negatively charged surfaces possessed excellent photocatalytic activity for the degradation of organic pollutant Rhodamine B (RhB). RhB was almost completely degraded in only 4 mins under ultraviolet−visible light irradiation. It was confirmed that the holes and.O2− played crucial roles in the RhB photocatalytic degradation process. This work provided a new strategy for the preparation of efficient photocatalysts. [ABSTRACT FROM AUTHOR]

Varying the ratio of MoS 2 on MoS 2 /rGO, and thus controlling the density of Pt SA oriented to grow on MoS 2 , a unique single atom catalyst with a 2D/2D structure was constructed, realising precise atomic control and efficient hydrogen evolution reaction under the acidic condition. [Display omitted] • A simple hydrothermal method was used to construct the 2D carrier, and the loading density of single-atom platinum (Pt SA) was precisely controlled by a directional growth strategy. • Pt SA -MoS 2 /rGO with optimised geometrical and electronic structures exhibits an ultra-low overpotential (η 10 = 11 mV) and long-term stability in acid condition for hydrogen evolution reaction (HER). • DFT shows that the increased loading density of Pt SA on the MoS 2 surface promotes the reduction of ΔG H* , which is the driving force for the kinetic process of electrocatalytic HER. An important but challenging task in single-atom catalysis is synthesizing a catalyst with controllable single-atom loading densities and no metal agglomeration. Here, we construct MoS 2 /rGO supports by a simple hydrothermal method and precisely control single-atom platinum (Pt SA) loading density by its targeted growth on MoS 2 for electrocatalysis. Using the optimized geometric and electronic structure, Pt SA -MoS 2 /rGO exhibits an ultra-low overpotential of 11 mV at − 10 mA cm−2 in 0.5 M H 2 SO 4 for electrocatalytic hydrogen evolution reaction (HER). First-principles calculations reveal that enhanced density of Pt SA on the MoS 2 surface favors the reduction of Gibbs free energy of hydrogen adsorption, facilitating the kinetic process of electrocatalytic HER. This work provides a new engineering route to fabricating a series of performance-tunable single-atom catalysts with controllable locations and loading densities. [ABSTRACT FROM AUTHOR]

[Display omitted] • The extraction performance of four green and low-cost ChCl-based DESs for phenol/toluene was investigated. • The effect of different glycols as HBDs on the separation was elucidated. • The intermolecular hydrogen bond interaction was analyzed by σ-profile based on COSMO-SAC model. • The extraction mechanism of DESs was revealed at molecular/atomic level. • Small molecular weight, short chain glycols as HBDs are more suitable for the separation process. Highly efficient separation of phenols from coal-to-liquids can enhance the economics of the coal conversion process. The selection of extractants with high extraction efficiency and low neutral oil entrainment is significant for energy development strategy. In this study, four ChCl-based DESs with different glycols as hydrogen bond donors (HBDs) were designed for the separation of phenol/toluene mixtures and the experimental results were analyzed by theoretical calculations. The experimental results showed that ChCl-EG had the highest extraction efficiency (94.02 %) and the least entrainment of toluene (0.449 g). Meanwhile, it could be regenerated and reused four times with no significant change in extraction capacity. The formation of hydrogen bonds between DESs and phenol was elucidated by σ-profile based on COSMO-SAC model. Multi-scale simulations and comparative analyses of the micro-mechanisms of the DESs system were carried out using quantum chemical (QC) and molecular dynamics (MD). It was shown that the attraction of DESs to phenol was mainly due to hydrogen bonds and vdW forces, with hydrogen bond interaction between Cl− in ChCl and H atom in phenol hydroxyl group being dominant. As the chain length of HBDs increased, the interaction of DESs with phenol was enhanced, while the entrainment of toluene also increased. Overall, the effect on the separation of phenol by different chain lengths of glycols as HBDs is elucidated. This study provides a theoretical reference for selecting and designing other DES extractants to separate phenol/toluene systems and similar systems. [ABSTRACT FROM AUTHOR]

• Study the effect of ketone structure on CO 2 absorption capacity by DFT & experiment. • CO 2 absorption capacity is improved more by adding one C atom on shorter ketones. • Straight-chain ketones have higher CO 2 absorption capacity than branched-chain ones. • Attribute CO 2 absorption behavior of favored ketones to higher H-bond interaction. • Interaction energy and NPA analyses support H-bond as the dominant mechanism. With regard to the physical absorbents for CO 2 removal, the alteration of carbon-chain structure may benefit the CO 2 absorption performance. However, the relationship between the carbon-chain structure of ketones absorbents and their CO 2 absorption capacity has rarely been studied, and the related mechanism is unclear. In this study, theoretical calculations and thermodynamic experiments were carried out to explore the effects of the carbon-chain length and isomerism of ketones on their CO 2 absorption performance. The density functional theory (DFT) simulations show that the F-∥ configuration is more stable than the others for the CO 2 +ketone complex in most cases. The followings are obtained according to the experimental results, which are pretty consistent with DFT calculations. The dissolution of CO 2 in the ketone is a typical physical process. As the number of carbon atom increases, the CO 2 absorption capacity of straight-chain ketones increases. Straight-chain ketones exhibit higher CO 2 absorption capacity than branched-chain ones. The effect of increasing carbon-chain length and isomerism on CO 2 absorption capacity are both stronger for the ketones with fewer carbon atoms; the influence mechanism can be attributed to different degrees of weak hydrogen-bond interaction between CO 2 and ketone molecules, suggested by the DFT simulation results. The above conclusions are beneficial for the development of potential CO 2 capture absorbents. In addition, the industrial application feasibility of surveyed ketone absorbents is also discussed. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Four DESs synthesised proved to be effective for phenol extraction. • The mechanism of DESs formation and separation was revealed at molecular/atomic scale. • The types and strengths of weak interactions of DESs with phenol and toluene were revealed. • Electrostatic and dispersion effects dominate the weak interaction energy. To gain more insight into the mechanism of the separation of phenols by deep eutectic solvents (DESs), four DESs: tetraethylammonium chloride (TEAC)-ethylene glycol (EG), TEAC-diethylene glycol (DEG), TEAC-triethylene glycol (TEG) and TEAC-tetraethylene glycol (TTEG) were prepared for the extraction of phenols from model oil. Experimental parameter optimization results indicated that four DESs were effective in extracting phenols, and TEAC-EG had the highest extraction efficiency (EE), with EE up to 98.95%. Subsequently, the formation mechanism of DESs and the extraction mechanism were revealed at the molecular/atomic level by quantum calculations using density functional theory (DFT). The most stable configurations, hydrogen bonding lengths, and interaction energies of DESs and corresponding systems have been calculated, and the weak interactions in the systems were visualized and further analyzed. The results showed that DESs formation were mainly due to a combined effect of hydrogen bonding and van der Waals (vdW) forces. Besides, hydrogen bonding and vdW forces between DESs and phenol were the main forces acting to extract phenol, and the hydrogen bonding within DESs was weakened when DESs interacted with phenol. [ABSTRACT FROM AUTHOR]

Highlights • Phenolic compounds in oils are separated by biodegradable biological reagents (BRs). • The separation is based on Brønsted acid-Lewis base interaction. • The BRs show the highest phenol extraction efficiency of 99.1% at room temperature. • The BRs can be regenerated using anti-extraction method without loss in efficiency. • The BRs are of biodegradation, no halide ions and no pollution to the environment. Abstract Phenolic compounds, which are widely used in producing synthetic fibers, engineering plastics, and other industrial organic chemicals, can be obtained from oil mixtures before further processing or applications by separation. Based on Lewis/Brønsted acid-base theory, we proposed the separation of phenolic compounds from oil mixtures using some environmentally benign biological reagents (BRs, including 1,3-dimethylxanthine-DMX, isonicotinamide-INA, and L-lysine-LYS). The effects of stirring time, temperature, initial phenol concentration, and BR:phenol mole ratio on phenol removal were studied in detail. LYS, INA and DMX show phenol removal efficiencies of 98.4%, 82.2%, and 66.6% from toluene at BR:phenol mole ratios of 1.6, 1.4, and 0.4, respectively, and those of 99.1%, 91.8%, and 74.6% from n -hexane at BR:phenol mole ratios of 2.20, 1.60, and 0.80, respectively, at room temperature. The BRs were regenerated with an anti-extraction method for four cycles without significant changes in separation efficiency and their properties. In addition, it is found that there is little toluene entrained in the biological reagents, which is as low as 2.3 wt% of separated phenol, indicating high purities of products. These BRs show the advantages of easy biodegradation, no corrosion to the equipment and containers, and no pollution to the environment. [ABSTRACT FROM AUTHOR]

In this article, dicationic ionic liquids (DILs), including N , N , N , N ′, N ′, N ′-hexaethyl-ethane-1,2-diammonium dibromide (HEDBr), N , N , N , N ′, N ′, N ′-hexaethyl-propane-1,3-diammonium dibromide (HPDBr) and N , N , N , N ′, N ′, N ′-hexaethyl-butane-1,4-diammonium dibromide (HBDBr), were designed and used to extract phenolic compounds from model oil and coal tar oil. The effects of stirring time, temperature, DIL:phenol mole ratio, and initial phenol concentration on the extraction of phenol were studied. It is found that the DIL:phenol mole ratio is only around 0.3 when the highest extraction efficiency of phenol is obtained. The extraction process completes within 5 min at room temperature, and the extraction efficiency is not dependent on temperature. Also, the ultimate phenol concentration remains constant despite the difference in initial phenol concentrations. Of these DILs, HPDBr shows the lowest ultimate phenol concentration of 3.9 g/dm 3 , and the extraction efficiency of phenol can reach as high as 97.0%. These DILs can be regenerated by anti-solvent method and reused several times without significant reduction in extraction efficiency. In addition, HPDBr was demonstrated to extract phenolic compounds from real coal tar oil, and its extraction efficiency of phenolic compounds is 92.7%. The mechanism, analyzed by FT-IR, shows that there is a hydrogen bond between phenol and DIL. [ABSTRACT FROM AUTHOR]

Indole plays a significant role in the production of products such as spices, medicines, and exogenous auxins. Deep eutectic solvents (DESs) formed by indole and quaternary ammonium salts (QASs, including tetraethylammonium chloride-TEAC, tetrapropylammonium chloride-TPAC, triethylmethyl-ammonium chloride-TEMAC) were found and proposed to efficiently extract indole from model wash oil. The effects of time, temperature, mole ratio of QAS to indole and initial indole concentration on the extraction of indole were studied. The results indicate that these QASs can extract indole from wash oil with efficiencies up to 96.7% (TPAC). The extraction process can be finished within 5 min. It is also found that the ultimate concentrations are almost identical for one kind of QAS although their initial concentrations are different, and the indole concentration in model wash oil can be reduced to a very low level of 1.3 g/dm 3 (TPAC). The maximum distribution coefficients of indole are 40.8 for TEAC, 91.9 for TPAC, and 29.5 for TEMAC at the studied conditions, and the extraction ability follows the order of TPAC > TEAC > TEMAC. Moreover, QASs in DESs can be reused without obvious reduction in extraction efficiency. The extraction mechanism was studied by FT-IR, and the results indicate that there is a hydrogen bond between QAS and indole. Finally, a comparison was made between this method and other methods to verify and demonstrate its desirable properties of efficiency and environmentally friendliness. [ABSTRACT FROM AUTHOR]

Forming deep eutectic solvents (DESs) by quaternary ammonium salts (QASs) and phenolic compounds to extract phenolic compounds from oil mixtures is effective. However, a small amount of neutral oil is entrained in the DESs. In this work, we proposed an anti-extraction method to remove the neutral oil entrained in DESs. Low-carbon alkanes (LCAs, including n -hexane, cyclohexane, and n -nonane) were added to model DESs to remove neutral oil. We found that the LCAs could effectively remove neutral oil entrained in the DESs. Of the three LCAs, n -hexane showed the best performance, and the removal rate of neutral oil could reach as high as 92.2%. The separation process could complete within 15 min, and the removal rate of neutral oil did not change significantly with temperature. In addition, n -hexane could effectively remove neutral oils in DESs formed by real coal tar and choline chloride. The neutral oil content in the phenolic compound product decreased to only 1.9 wt%, which greatly improves the purity of the phenolic compound product. [ABSTRACT FROM AUTHOR]

Phenolic compounds (such as phenol, cresol sand xylenol), which are basic materials for the organic chemical industry, are mainly produced from coal liquefaction oil, coal tar, petroleum, and biomass pyrolysis oil. It has been reported that the separation of phenols from oil with forming deep eutectic solvents based on quaternary ammonium salt (QAS) is an efficient and environmentally friendly method. However, the phase equilibrium of QAS + phenol + oil mixtures has not been reported in the literature. In this work, the phase equilibrium for separating phenol from model oil with 2-hydroxy- N , N , N -trimethyl-ethanaminium chloride (ChCl), N , N , N -triethyl-ethanaminium chloride (TEAC), and N , N , N -trimethyl- methanaminium chloride (TMAC) was studied. Phase equilibria of three ternary systems of toluene + phenol + QAS were measured at 25.0, 40.0 and 65.0 °C, and phase behaviors of the ternary systems were studied. Effects of temperature, type and dosage of QAS on the equilibrium were investigated. The results show that low temperatures are beneficial to extraction of phenol and the phenol removal efficiency decreases with increasing temperature. Among the QASs, TEAC has the strongest ability to separate phenol, but the concentration of toluene entrained in the DES phase is the largest. Only TMAC is dissolved in the oil phase to a small extant, which can cause the loss of extractant. ChCl not only has high phenol removal efficiency, but also causes a small concentration of toluene entrained in the DES phase, which shows that ChCl is an efficient and environmentally friendly extractant. [ABSTRACT FROM AUTHOR]

Phase equilibria of the binary systems of high pressure CO 2 + deep eutectic solvents (DESs) formed by quaternary ammonium salts (QASs, including 2-hydroxy- N , N , N -trimethyl-ethanaminium chloride, ChCl; N , N , N -trimethyl-methanaminium chloride, TMAC; and N , N , N -triethyl-ethanaminium chloride, TEAC) and phenol were measured at temperatures from 313.15 K to 333.15 K, pressures from 1.71 MPa to 13.3 MPa and mole ratios of phenol to QAS from 2.00 to 4.00. It has been found that two-phase equilibrium exists at all the studied conditions. The solubility of phenol in the CO 2 phase and the solubility of CO 2 in the DES phase at different pressures, temperatures, mole ratios of phenol to QAS have been obtained. Both the solubility of phenol in the CO 2 phase and the solubility of CO 2 in the DES phase formed by ChCl and phenol shows the largest, while those in the DES phase formed by TEAC and phenol shows the smallest. This work provides phase equilibrium data for phenol extraction and QAS regeneration. [ABSTRACT FROM AUTHOR]

• From orange red to blue in one phosphor via excitation-driven strategy. • The luminescence color of Bi3+ was fine-tuned by solid solution composition. • Bi3+ ions are used as doping ions, which can be carried out in air. • Solid solution constructed by isostructural end components. Most lanthanide doped phosphors need to be prepared in a reducing atmosphere, such as phosphors doped by Eu2+ and Ce3+ ions with d-f transition. In contrast, the doping ion Bi3+ selected in this paper has more advantages. Moreover, the 6S electrons of bare bismuth are very sensitive to the surrounding coordination field environment, which makes it highly tunable. A new type of solid solution Sr 3−x Gd x AlO 4+x F 1−x designed by the isostructural end components Sr 3 AlO 4 F and GdSr 2 AlO 5 well promotes the luminescence of Bi3+ ion. By adjusting the concentration of Bi3+/Eu3+, the phosphor can be tuned from blue to red, which is due to the energy transfer caused by dipole–dipole interaction between Bi3+ and Eu3+. Surprisingly, by means of excitation-driven, the emission peak position of Bi3+ ions can also be moved from ~425 nm to ~437 nm, and red shift occurs, so as to realize the tuning of the fluorescence from orange red to blue. We speculate that this is induced by the presence of multiple emission centers of Bi3+, and different absorption strength of Bi3+ and Eu3+. In addition, the thermal response of Bi3+ and Eu3+ ions to temperature is different. They are thermally quenched by energy level cross relaxation (ELCR) and multi-phonon deexcitation (MPD), respectively. The maximum relative sensitivity of optical thermometry based on fluorescence intensity ratio (FIR) is approximately 1.17 %K−1 at 323 K, which is higher than that of previously reported Bi3+ and Eu3+ co-doped phosphors. At 523 K, we also obtained a high absolute sensitivity of 0.0064 K−1. Consequently, the solid solution phosphor prepared by us has a far-reaching application prospect in the field of temperature monitoring. [ABSTRACT FROM AUTHOR]

• From orange red to blue in one phosphor via excitation-driven strategy. • The luminescence color of Bi3+ was fine-tuned by solid solution composition. • Bi3+ ions are used as doping ions, which can be carried out in air. • Solid solution constructed by isostructural end components. Most lanthanide doped phosphors need to be prepared in a reducing atmosphere, such as phosphors doped by Eu2+ and Ce3+ ions with d-f transition. In contrast, the doping ion Bi3+ selected in this paper has more advantages. Moreover, the 6S electrons of bare bismuth are very sensitive to the surrounding coordination field environment, which makes it highly tunable. A new type of solid solution Sr 3−x Gd x AlO 4+x F 1−x designed by the isostructural end components Sr 3 AlO 4 F and GdSr 2 AlO 5 well promotes the luminescence of Bi3+ ion. By adjusting the concentration of Bi3+/Eu3+, the phosphor can be tuned from blue to red, which is due to the energy transfer caused by dipole–dipole interaction between Bi3+ and Eu3+. Surprisingly, by means of excitation-driven, the emission peak position of Bi3+ ions can also be moved from ~425 nm to ~437 nm, and red shift occurs, so as to realize the tuning of the fluorescence from orange red to blue. We speculate that this is induced by the presence of multiple emission centers of Bi3+, and different absorption strength of Bi3+ and Eu3+. In addition, the thermal response of Bi3+ and Eu3+ ions to temperature is different. They are thermally quenched by energy level cross relaxation (ELCR) and multi-phonon deexcitation (MPD), respectively. The maximum relative sensitivity of optical thermometry based on fluorescence intensity ratio (FIR) is approximately 1.17 %K−1 at 323 K, which is higher than that of previously reported Bi3+ and Eu3+ co-doped phosphors. At 523 K, we also obtained a high absolute sensitivity of 0.0064 K−1. Consequently, the solid solution phosphor prepared by us has a far-reaching application prospect in the field of temperature monitoring. [ABSTRACT FROM AUTHOR]