Study on the solid-liquid equilibrium and thermodynamic model of the L-phenylalanine + L-tryptophan + water system.

Amino acids hold significant importance in the diagnosis and treatment of various chronic diseases. Accurate solid-liquid equilibrium data are the key to drug synthesis and chemical production. However, the studies on the solid-liquid equilibrium of amino acids remain limited. In this work, the solid-liquid equilibrium of the L-tryptophan + L-phenylalanine + water ternary system under atmospheric pressure at temperatures of 278.15 K-318.15 K was explored via isothermal solution saturation. The isothermal equilibrium phase diagram of the ternary system was constructed. The obtained solid-liquid equilibrium data were correlated with a semi-empirical-model, yielding thermodynamic parameters pa, pb, pc, and k. Furthermore, the model can be used to effectively predict the solid-liquid equilibrium data of ternary systems at other temperatures, and the dY and dP are 0.005 and 4.34%, respectively. The solid-liquid equilibrium data and ternary equilibrium phase diagrams of the system were utilized for the separation and purification of an L-tryptophan and L-phenylalanine mixture. By employing thermodynamic models to calculate the relevant phase diagram data for mixtures with different proportions, effective separation and purification of the mixture could be achieved using the principles of variable temperature phase diagrams. These works are valuable for optimizing chemical processes and have practical implications in the field.

The structural and hydrogen bonding properties of ionic liquid-co-solvent binary mixtures: the distinct behaviors of two anions.

In practical applications, ionic liquids are often mixed with co-solvents. Understanding their structures and the interactions between them is a prerequisite for expanding their range of applications. In this work, spectroscopic and theoretical methods were employed to explore the structure and hydrogen bonding behaviors of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMIMTFSI)/1-ethyl-3-methylimidazolium thiocyanate (EMIMSCN) and co-solvents. It can be concluded that the hydrogen bonds associated with C2-H and C4,5-H are enhanced with the addition of co-solvents in the EMIMTFSI-DMSO system, while those associated with C4,5-H are weakened in the EMIMSCN-DMSO system. Infrared and excess spectra in the v(imidazolium C-H) range of EMIMSCN-CD3CN/CD3COCD3 systems further indicate that the abnormal change of hydrogen bonds associated with C4,5-H can be attributed to [SCN]-. These differences can be explained by the change of the primary interaction site. For EMIMTFSI, the primary interaction site in ion pairs and ion clusters is always C2-H, while for EMIMSCN, the primary interaction site in ion pairs is C2-H, and in ion clusters, it becomes C4,5-H. In the EMIMTFSI-DMSO system, the co-solvent primarily interacts with C4,5-H, while in the EMIMSCN-DMSO/CH3CN/CH3COCH3 systems, it primarily interacts with C2-H. In addition, several complexes are identified through excess infrared spectra and DFT calculations.

Guest-Stimulated Nonplanar Porphyrins in Flexible Metal-Organic Frameworks.

Nonplanar porphyrins with out-of-plane distortions play crucial roles in many biological functions and chemical applications. The artificial construction of nonplanar porphyrins usually involves organic synthesis and modification, which is a highly comprehensive approach. However, incorporating porphyrins into guest-stimulated flexible systems allows to manipulate the porphyrin distortion through simple ad/desorption of guest molecules. Here, a series of porphyrinic zirconium metal-organic frameworks (MOFs) is reported that exhibit guest-stimulated breathing behavior. X-Ray diffraction analysis and skeleton deviation plots confirm that the material suffers from porphyrin distortion to form a ruffled geometry under the desorption of guest molecules. Further investigation reveals that not only the degree of nonplanarity can be precisely manipulated but also the partial distortion of porphyrin in a single crystal grain can be readily achieved. As Lewis acidic catalyst, the MOF with nonplanar Co-porphyrin exhibits active properties in catalyzing CO2 /propylene oxide coupling reactions. This porphyrin distortion system provides a powerful tool for manipulating nonplanar porphyrins in MOFs with individual distortion profiles for various advanced applications.

UV-B radiation alleviated detrimental effects of polymethyl methacrylate microplastics on marine diatom Thalassiosira pseudonana.

Microplastics (MPs) in marine environments simultaneously affect microalgae with UV-B radiation, while their joint effecting mechanisms remain largely unknown. To fill this research gap, the joint effects of polymethyl methacrylate (PMMA) MPs and UV-B radiation (natural environments intensity) on the model marine diatom Thalassiosira pseudonana were investigated. Antagonism was found between the two factors with regards to population growth. Furthermore, we found more inhibited population growth and photosynthetic parameters when pre-treated with PMMA MPs compared to pre-treated with UV-B radiation before joint-treated by the two factors. Transcriptional analysis elucidated that UV-B radiation could alleviate the down-regulation of photosynthetic (PSII, cyt b6/f complex and photosynthetic electron transport) and chlorophyll biosynthesis genes caused by PMMA MPs. Besides, the genes encoding carbon fixation and metabolisms was up-regulated under UV-B radiation, which could provide extra energy for the enhanced anti-oxidative activities and DNA replication-repair processes. These consequences showed that the toxicity of PMMA MPs was comprehensively alleviated when T. pseudonana was jointed treated by UV-B radiation. Our results reveled the underlying molecular mechanisms of antagonistic effects between PMMA MPs and UV-B radiation. This study provides important information that environmental factors like UV-B radiation should be considered when accessing the ecological risks of MPs on marine organisms.

Comparative study of the hydrogen bonding interactions between ester-functionalized/non-functionalized imidazolium-based ionic liquids and DMSO.

There have been some studies on the microscopic properties of ester-functionalized ionic liquids (ILs), but the microscopic properties of their mixtures with co-solvents have seldom been reported. In practical applications, ILs are usually used together with co-solvents. Therefore, it is very important to study the microstructure of ester-functionalized ILs and co-solvents. In this work, the hydrogen bonding interactions between ester-functionalized IL 1-acetoxyethyl-3-methylimidazolium tetrafluoroborate (AOEMIMBF4) and DMSO were studied using spectroscopic methods and quantum chemical calculations. Non-functionalized IL 1-butyl-3-methylimidazolium tetrafluoroborate (BMIMBF4) and DMSO were used for comparison. The results indicate that (1) by adding DMSO, the hydrogen bonding interactions of ν(C2-H) were enhanced, and DMSO could form hydrogen bonds with anions and cations simultaneously. (2) The incorporation of an ester group could enhance the hydrogen bonding interactions. (3) Both the stretching vibration of C2-H and CO indicated changes in the microscopic structure: AOEMIMBF4 ion clusters first interacted with DMSO, then broke into AOEMIMBF4-DMSO complexes and finally existed as [AOEMIM]+/[BF4]--DMSO complexes.

[Clinical application of modified fistulectomy in the treatment of congenital pyriform sinus fistula based on segmental anatomy of fistula].

Objective:To discuss the clinical application and significance of the modified piriform fossa fistulectomy based on segmental anatomy of fistula. Methods:The clinical data of 84 patients with CPSF treated by modified pyriform sinus fistulectomy were analyzed retrospectively. The modified piriform fossa fistula resection adopts the fistula anterograde anatomy method to fine dissect the fistula. The operation procedure can be summarized into four parts: retrograde anatomy of recurrent laryngeal nerve, anatomy of external branch of superior laryngeal nerve, anterograde anatomy of fistula and partial thyroidectomy. Results:All 84 patients successfully completed the operation and discharged from the hospital. The operation time was（64.6±20.0） min, the intraoperative bleeding was（19.6±13.0） mL, and the average hospital stay was（6.8±1.1） d. Postoperative infection occurred in 1 case（1.19%）, temporary vocal cord paralysis in 1 case（1.19%）, no bleeding, pharyngeal fistula, dysphagia, permanent vocal cord paralysis and choking cough. The incidence of complications was 2.3%（2/84）. No complications such as permanent vocal cord paralysis and hypothyroidism occurred. Follow up for 57-106（Median 74） months showed no recurrence. Conclusion:A modified procedure based on segmental dissection of the fistula not only simplifies the traditional procedure, but also procedures the specific steps to provide a targeted and precise resection, which provides a proven surgical solution for complete eradication of the lesion and significantly reduces complications and recurrence.

Study on vapor-liquid equilibrium and microscopic properties of DL-proline, L-glutamic acid, and L-serine aqueous solutions.

The vapor-liquid equilibrium (VLE) in aqueous amino acid solutions is essential in chemical production, such as purification, isolation, or crystallization of amino acid intermediates. In this work, VLE of DL-proline, L-glutamic acid, and L-serine aqueous solutions was measured at pressures ranging from 4.82 to 102.58 kPa. The developed model was successfully applied to correlate experimental data with temperatures in the range of 298.15-382.75 K. Model parameters (h, τ w , i ( 0 ) , τ w , i ( 1 ) , τ i , w ( 0 ) , and τ i , w ( 1 ) ) were given. Moreover, the amino acid aqueous solution was investigated by Fourier transform infrared spectroscopy (FTIR). By analyzing infrared spectra, the strength of intermolecular interactions was obtained, and the structure-activity relationship between the microscopic interactions and the VLE was established.

The molecular behavior of pyridinium/imidazolium based ionic liquids and toluene binary systems.

Imidazolium and pyridinium-based ionic liquids (ILs) have attracted increasing attention in the extraction of aromatic VOCs. However, fundamental studies on the mechanism of capturing aromatic VOCs have been less reported. In this work, the interactions between two ILs, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMIMTFSI) and N-butylpyridinium bis(trifluoromethylsulfonyl)imide (BpyTFSI), and toluene (C6H5CH3), were investigated by using attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), excess infrared spectroscopy, hydrogen nuclear magnetic resonance (1H NMR) spectroscopy and quantum chemical calculations. Some conclusions were obtained as follows: (1) H atoms on EMIMTFSI/BpyTFSI were located above or below the benzene ring and were mainly formed as C2-Hπ bonds and C2,6-Hπ bonds with C6H5CH3, respectively. C-Hπ bonds played a significant role in capturing aromatic compounds. (2) Upon adding C6H5CH3, the two IL-C6H5CH3 system's interaction strength was as follows: EMIMTFSI-C6H5CH3 > BpyTFSI-C6H5CH3. (3) Since C6H5CH3 was unable to disrupt the interactions between cations and anions of ion pairs in the two studied IL-C6H5CH3 systems, only ion cluster-C6H5CH3 and ion pair-C6H5CH3 complexes were observed. This work may provide theoretical insights into the separation mechanism for capturing VOCs.

[Classification and surgical strategy of Work â congenital first branchial cleft anomaly based on adjacent anatomy].

Objective:To explore the adjacent anatomic relationship and classification of Work Ⅰ congenital first branchial cleft anomaly（CFBCA） in order to guide clinical practice. Method:The data of 48 cases of Work Ⅰ CFBCA with complete data were analyzed retrospectively. Result:All 48 lesions were completely resected. 48 sides（100.0%） were anatomically preserved facial nerve, partial parotidectomy was performed on 33 sides（68.8%）, superficial lobe+deep lobe partial parotidectomy was performed on 9 sides（18.8%）, and 6 sides（12.5%） was not performed parotidectomy. External auditory canal reconstruction was performed on 32 sides（66.7%）; 43 sides（89.6%） underwent the anatomical preservation of the auricular lobe branch of the great auricular nerve; 9 sides（18.8%） was performed selective cervical lymphadenectomy at the same time. 45 sides of Work Ⅰ CFBCA presented irregular cystic or lobulated structure, the lesion was located below and behind the junction of the external auditory meatus bone and cartilage and distributed along the longitudinal axis of the external auditory canal; 3 sides were isolated in superficial lobe parenchyma of parotid gland. All lesions were located on the superficial surface of the main trunk and branches of the facial nerve. The average value of the shortest vertical distance between the lower edge of the lesion and the outlet of the main trunk of the facial nerve at the stylomastoid foramen was 7.2 （0-13.4 ）mm. Based on preoperative images and intraoperative findings, according to the adjacent relation with external auditory meatus , parotid gland and facial nerve, the classification of Work Ⅰ congenital first branchial cleft anomaly is proposed, which is specifically divided into 4 types: C1（posterior wall of the external auditory meatus） 17 cases（35.4%）, C2（inferior wall of the external auditory meatus） 13 cases（27.1%）, C3 （multi wall of the external auditory meatus） 15 cases（31.3%）, C4（isolated from parotid gland parenchyma） 3 cases（6.3%）. Conclusion:Work Ⅰ CFBCA has a close relationship with the adjacent anatomy of the region, and familiar with the classification of Work Ⅰ congenital first branchial cleft anomaly is helpful for the treatment of type and accurate resection.

The effect of introducing an ether group into an imidazolium-based ionic liquid in binary mixtures with DMSO.

Ether-functionalized ionic liquids (ILs) have successfully been employed in diverse applications, but their interactions with other solvents are not understood well. In this work, mixtures of 1-methoxyethyl-3-methylimidazolium bis(fluorosulfonyl)imide (EOMIMFSI) and dimethylsulfoxide (DMSO) are studied in terms of their solution structure and hydrogen bonding interactions. The corresponding alkyl-substituted IL 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide (EMIMFSI) is analyzed for comparison. A combination of FTIR spectroscopy, excess spectroscopy, and quantum chemical calculations is employed for this purpose. The datasets allow drawing a number of conclusions as follows: (1) the ether group forms intramolecular hydrogen bonds that compete with anions and DMSO; hence, introducing ether groups into the imidazolium-based IL leads to the weakening of hydrogen bonds in the mixtures. (2) With the help of excess spectra and quantum chemical calculations, some complexes such as ion clusters, ion pairs, and individual ions were identified and assigned in the two systems. The solution structures at different concentrations were examined by analyzing the excess spectra of ν(C2-H) and ν(C-D) in the two IL-DMSO-d6 systems. (3) The introduced ether groups result in changes of the main interaction sites, which were found to be concentration-dependent. In the EOMIMFSI-DMSO system, when isolated ions are the main existing form, the C2-Hs are still the main sites interacting with DMSO. However, when ion pairs or larger ion clusters are the main existing species, the C4-Hs are the main sites interacting with DMSO.

The Effects of NaI, KBr, and KI Salts on the Vapor-Liquid Equilibrium of the H2O+CH3OH System.

The vapor-liquid equilibrium (VLE) in chemical engineering is indispensable for the design of equilibrium separation processes such as distillation, absorption, extraction, and crystallization. VLE data were measured for H2O+CH3OH+NaI, H2O+CH3OH+KBr, and H2O+CH3OH+KI systems. By analyzing and summarizing the results of H2O+Methanol+Alkali metal halide systems, the salt effects of NaI, KBr, and KI on the vapor-liquid equilibrium were obtained. Simultaneously, a model based on the NRTL equation (non-random two liquid) was proposed to correlate and calculate the VLE for the systems. In addition, the assumption of solvation based on hydration was introduced in this model. The proposed model can be successfully used to calculate the VLE for H2O+Methanol+Alkali metal halide systems.

Research on the removal of near-well blockage caused by asphaltene deposition using sonochemical method.

Near-well blockage caused by asphaltene deposition often occurs during the process of crude oil exploitation. It can reduce the porosity and permeability of reservoirs and seriously affects the migration and exploitation of oil and gas. In this paper, removing near-well blockage caused by asphaltene deposition using sonochemical method is investigated. Six PTZ transducers with different parameters are used to study the deplugging effect. Results show that the optimal ultrasonic frequency and power for plugging removal are 20 kHz and 1000 W respectively. it is found that lower ultrasonic frequency is good for asphaltene deposition plug removal when ultrasonic power is constant; as the power of the sensor increases, the effect of removing the asphaltene deposition plug gets better, ultrasonic power can well make up for the attenuation of ultrasonic energy caused as frequency increases; the effects of removing asphaltene deposition plug for the three cores with different initial gas logging permeability all get worse no matter what type of transducer is used; the effect of asphaltene deposition plug removal for the three cores samples all become better and then tend to be stable as ultrasonic treatment time increases further; considering of reducing construction cost and oil reservoir protection, ultrasonic processing has a lot of unexampled advantages compared with chemical injection, such as good adaptability, low cost, simple operation, non-pollution and benefit for the sustainable development of oil field; affected by the synergistic effect of ultrasonic and chemical agents, the combined treatment effect of ultrasound and chemical agents is significantly better than using ultrasound or chemical agents alone.

Promoting Nanozyme Cascade Bioplatform by ZIF-Derived N-Doped Porous Carbon Nanosheet-based Protein/Bimetallic Nanoparticles for Tandem Catalysis.

Nanozymes are a class of nanomaterials with enzyme-like activities that have been extensively studied for their possibilities and superiorities over natural enzymes. Intelligent design and fabrication of a nanozyme platform with highly efficient and stable tandem enzyme characteristics is necessary. Herein, a nanozyme cascade promoting bioplatform based on protein/bimetallic nanoparticles attached to ZIF-derived multilayer N-doped carbon nanosheets is proposed. Due to the carbon-based large surface area and solitary pairs of nitrogen electrons, the metal could be riveted to the carbon-based surface and reduced in situ to nanoparticles. Simultaneously, the addition of BSA has made it possible to establish a biological platform. The obtained BSA-PtAu@CNS has a linear range of 2 × 10-6 to 2 × 10-3 M for H2O2 and apparent dynamic Km of 0.005 × 10-3 M, which shows stronger affinity with H2O2 than HRP. The nanohybrid could adapt to severe reaction environment and enable prominent tandem dual-enzyme activity for glucose sensing. As a result, the cascade nanozyme bioplatform based on BSA-PtAu@CNS is accomplished and provides insights for subsequent biocompatible nanomaterials for use in medical and diagnostic applications.

Bimetallic Metal-Organic Framework Derived Metal-Carbon Hybrid for Efficient Reversible Oxygen Electrocatalysis.

Development of cost-effective electrocatalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is key to enabling advanced electrochemical energy conversion technologies. Here, a novel nitrogen-doped metal-carbon hybrid (NiCo/CN) with a unique 3D hierarchical structure, consisting of uniformly distributed bimetallic nanoparticles encapsulated by partially graphitized N-doped carbon shells, is fabricated by a one-step pyrolysis of a nanoscale metal-organic framework as precursor, which exhibits excellent activity for both ORR and OER. The surface chemical changes on the carbon hybrid probed by X-ray photoelectron spectroscopy (XPS) reveal the presence of favorable electronic interaction at the metal-nitrogen-carbon interface. Remarkably, the NiCo/CN catalyst prepared at high temperature (800°C) manifests a comparable performance to a commercial Pt/C catalyst for the ORR, but also superior stability, path selectivity and methanol tolerance. On the other hand, the E onset (1.48 V vs. reversible hydrogen electrode) and E j = 10 mA/cm 2 of NiCo/CN-800 for OER is very close to the state-of-the-art noble catalyst RuO2 (Eonset = 1.46 and E j = 10 mA/cm 2 ) along with superior stability over 20 h of operation. The excellent catalytic property is attributable to the unique nanostructure, high porosity and the constructive synergistic effects of the elements M, N, and C.

Electrochemical thrombin aptasensor based on using magnetic nanoparticles and porous carbon prepared by carbonization of a zinc(II)-2-methylimidazole metal-organic framework.

A homogeneous electrochemical aptasensor was obtained by modifying a glassy carbon electrode (GCE) with a porous carbon nanomaterial (Z-1000, about 70 nm, deteced by transmission electron microscopic) that was obtained by carbonization of a zinc(II)-2-methylimidazole metal-organic framework. Z-1000 possesses a large specific surface and outstanding electrochemical properties. A thrombin-binding aptamer (CP) was immobilized on the magnetite nanoparticles MNPs by the condensation reaction and further combined with reporter probe (RP) that is functionalized with electroactive methylene blue (MB). In the presence of thrombin, the CP was specifically recognized with it to form the CP/MNP/Thb complex, and the RP was dissociated from MNPs. The released RP was captured by the modified GCE through π-stacking interaction between nucleobases and carbon nanostructure. The electrical signal generated by MB can be monitored by differential pulse voltammetry (DPV). Under the optimized conditions, the DPV peak current at around -0.28 V (vs. SCE) increases with thrombin concentration. The sensor has a detection limit of 0.8 fM of thrombin and a linear range that extends from 10 fM to 100 nM. It was successfully applied to the analysis of spiked serum. The recoveries are 98.1-99.4% and RSDs are 3.9%-4.0%. Conceivably, this aptasensor scheme can be easily extended to other proteins and gives inspiration to manufacture sensitive aptasensor. Graphical abstract A homogeneous electrochemical aptasensor is obtained by modifying a glassy carbon electrode with the MOF-derived porous carbon. The sensor has a detection limit of 0.8 fM and a wide linear range from 10 fM to 100 nM for thrombin detection.

Vapor-Liquid Equilibria Study of the LiCl + CaCl2 + H2O System.

Vapor-liquid equilibrium (VLE) data are measured and reported for the LiCl + CaCl2 + H2O system. The experimental procedures were carried out with pressures between 6 and 101.3 kPa in a computer-controlled glass apparatus. We obtained the relationship between solubility of salt and vapor pressure by analyzing and summarizing the results. Then, a modified NRTL model based on the hypothesis of hydration was used in this paper. By correlation of literature and experimental data for LiCl + H2O, CaCl2 + H2O, and LiCl + CaCl2 + H2O (pressure spanning from 5 to 101.3 kPa), some parameters were modified for improving the accuracy of the calculation. Meanwhile, the model was successfully applied to predict the VLE data in LiCl + CaCl2 + H2O systems with the modified binary parameters.

Research on ultrasound-assisted demulsification/dehydration for crude oil.

Crude oil demulsification and dehydration are important links in the process of crude oil exploitation, transportation, and refining. In recent years, with the development of crude oil exploitation, the content of colloid and asphaltene in crude oil has been increasing, and the properties of crude oil emulsion have become more stable. In addition, the development and application of oil recovery technology and the use of a large number of oilfield chemicals have made the composition of crude oil more complicated. The water content and salt content of oil produced fluid increase year by year, which aggravates the task of crude oil dehydration and desalination. Therefore, it is particularly important to study the demulsification and dehydration of crude oil. In this paper. Research on ultrasound-assisted demulsification/dehydration for crude oil in investigated. Results indicate that the demulsification effect varies with the increase of ultrasonic radiation time, but the difference is not significant; with the increase of temperature, the effect of ultrasonic on the demulsification of crude oil emulsion is decreased, or the advantages of ultrasonic can be fully displayed only at low temperature; ultrasonic power has a critical value, when it is lower than this critical value, ultrasonic wave acts as demulsifying agent, and with the increase of power, dehydration rate of the crude oil emulsion increases; when higher than the critical value, the separated oil and water can be re-emulsified; ultrasonic demulsification can both shorten settling time and reduce the amount of demulsifier; ultrasound is suitable for demulsification and dehydration of crude oil emulsions with high water content. Results also prove that chemical demulsifier has a better effect for crude oil demulsification /dehydration than that of ultrasonic treatment alone. In addition, recent progress on ultrasonic demulsification equipment is introduced. The purpose of this paper is to offer equipment and technical support for crude oil demulsification/ dehydration.

Study on ultrasonic treatment for municipal sludge.

Ultrasonic technique has attracted wide attention due to its advantages of no secondary pollution, high decomposition speed and simple equipment in the treatment of municipal sludge. In this paper, study on ultrasound-chemical treatment for municipal sludge in investigated. Results indicate that ultrasonic waves can destroy sludge floc structure and cell walls, release intracellular organic matter, and accelerate the hydrolysis process; ultrasonic can improve the sedimentation and dewatering performance of sludge; ultrasonic wave can produce a sponge effect on sludge, which makes the water flow through the channel more easily from the wave surface, thereby agglomerating the sludge particles and increasing the particle size; ultrasound can promote coagulation; ultrasound can also improve the activity of excess sludge, and improve the efficiency of anaerobic digestion process and the final biogas production. Ultrasound-Cationic polyacrylamide (CPAM) treatment can undermine the repulsion between particles to a certain extent and destabilizes sludge flocs. In addition, the adsorption and bridging action of the flocculant CPAM further agglomerates the sludge particles, and the water in the sludge is squeezed out to be converted into free water, which further improves the dewatering performance of the sludge, thereby reducing the moisture content of the filter cake.

A hybrid material composed of reduced graphene oxide and porous carbon prepared by carbonization of a zeolitic imidazolate framework (type ZIF-8) for voltammetric determination of chloramphenicol.

Porous carbon was prepared from a zeolitic imidazolate framework (type ZIF-8) by carbonization at 800 °C (Z-800). A hybrid material was then obtained by direct co-electrodeposition of Z-800 with graphene oxide (Z-800/rGO). Z-800 is N-doped with good electrical conductivity and displays electrocatalytic activity. Z-800 readily undergoes mass transfer and also prevents graphene to agglomerate during electroanalysis. The hybrid was placed on a glassy carbon electrode (GCE) to obtain an electrochemical sensor for chloramphenicol (CAP) detection. Under the optimized conditions, the response of the modified GCE (typically measured at a low potential of -0.07 V vs. Ag/AgCl) is linear in the 1 to 180 µM CAP concentration range with a 0.25 µM detection limit (S/N = 3). In our preception, the method has a wide scope in that it may be applied to the preparation of various kinds of other (doped) porous carbon/rGO composites for use in (bio)chemical sensors. Graphical abstract Schematic presentation of the preparation process of the materials and the electrochemical detection of chloramphenicol.

Vapor-Liquid Equilibrium Study of LiBr + H2O and LiBr + CaCl2 + H2O Systems.

Vapor-liquid equilibrium (VLE) data and modeling for LiBr + H2O and LiBr + CaCl2 + H2O are reported in this paper. This work focuses on the experimental determination of the boiling point of LiBr + H2O and LiBr + CaCl2 + H2O solutions with vapor pressures between 6 and 101.3 kPa and the total molality of salt ranging from 0 to 21.05 mol•kg-1. The procedures were carried out in a computer-controlled glass apparatus. The relationship between the boiling point and saturated vapor pressure is obtained, and Xu's model is used to correlate and predict the VLE. By correlation of the data (literature and experimental) for LiBr + H2O and LiBr + CaCl2 + H2O, the parameters are obtained. We compared the results with the ElecNRTL model and Pitzer model. The parameters for the LiBr + H2O, CaCl2 + H2O, and LiBr + CaCl2 + H2O systems can be successfully used to calculate and predict the VLE data.