Experimental study on the durability of the polydopamine functionalized gas–liquid–solid microreactor for nitrobenzene hydrogenation

As a promising technique for multiphase catalytic reactions, the widespread applications of gas–liquid–solid microreactors are still limited by poor durability. Hence, in this work, a method for the preparation of Pd nanocatalysts inside a gas–liquid–solid microreactor was proposed to realize long-term durability using electroless deposition on the polydopamine functionalized surface followed by hydrogen reduction. This method not only increases the utilization efficiency of the Pd ions but also improves the durability of the microreactor. The chemical composition and topography characterization of the fabricated catalyst layer were tested using XPS and FESEM, respectively. The results indicated that the incorporation of hydrogen reduction resulted in nearly all palladium ions being reduced and the palladium nanoparticles were dispersed uniformly on the polydopamine modified surface. The microreactor prepared by this method exhibited high durability and high nitrobenzene conversion as compared to the traditional electroless catalyst deposition. Besides, it was shown that the increased inlet nitrobenzene concentration and flow rates played a negative role in the durability. The longer microreactor exhibited a better durability.

As a promising technique for multiphase catalytic reactions, the widespread applications of gas–liquid–solid microreactors are still limited by poor durability.     

Hydrogen storage performance of the multi-principal-component CoFeMnTiVZr alloy in electrochemical and gas–solid reactions

The single-phase multi-principal-component CoFeMnTiVZr alloy was obtained by rapid solidification and examined by a combination of electrochemical methods and gas–solid reactions. X-ray diffraction and high-resolution transmission electron microscopy analyses reveal a hexagonal Laves-phase structure (type C14). Cyclic voltammetry and electrochemical impedance spectroscopy investigations in the hydrogen absorption/desorption region give insight into the absorption/desorption kinetics and the change in the desorption charge in terms of the applied potential. The thickness of the hydrogen absorption layer obtained by the electrochemical reaction is estimated by high-resolution transmission electron microscopy. The electrochemical hydrogen storage capacity for a given applied voltage is calculated from a series of chronoamperometry and cyclic voltammetry measurements. The selected alloy exhibits good stability for reversible hydrogen absorption and demonstrates a maximum hydrogen capacity of ∼1.9 wt% at room temperature. The amount of hydrogen absorbed in the gas–solid reaction reaches 1.7 wt% at 298 K and 5 MPa, evidencing a good correlation with the electrochemical results.

The single-phase multi-principal-component CoFeMnTiVZr alloy was obtained by rapid solidification and examined by a combination of electrochemical methods and gas–solid reactions.     

Effective treatment of emulsified oil wastewater by the coagulation–flotation process

Ship emulsified oil wastewater was used as the research object in this study. The highly efficient coagulant demulsification degreasing mechanism and microbubble flotation technology were combined and the effects of coagulant type and dosage amount on the demulsification of emulsified oil wastewater were evaluated. The influence of the mixed coagulation effect of pH values, temperature, and hydraulic condition parameters were determined and water intake, air intake, and oil content were regulated. The coagulant for the demulsification of emulsified oil wastewater was screened; the dosage was 500 mg L⁻¹, and the removal capacity of the coagulant was in the following order: polyaluminum ferric chloride (PAFC) > polyaluminum chloride (PAC) > polysilicate aluminum ferric sulfate (PSAFS) > alum > Al₂(SO₄)₃ > polyferric sulfate > FeCl₃. Polyacrylamide (PAM) with added water was used to further reduce the oil content. The PAFC, PAC, and PSAFS were selected as coagulation–air flotation dynamic test alternative agents. The investment quantities of PAFC, PSAFS and PAM were 300 mg L⁻¹, 300 mg L⁻¹ and 30 mg L⁻¹, respectively. The stirring time was 5 min, the pH value was 6.5–6.9, the flow rate was 0.25 m³ h⁻¹, the oil content of the emulsified oil wastewater was 3000–5000 mg L⁻¹ and the effluent oil was stable below 15 ppm. The microbubble generation device using air flotation effluent was used in the two air flotation treatments to enhance the device efficiency. The air flotation device adopted the structural design of the upper part of the water inlet and the lower part of the micro-air bubble, which can increase the collision probability of the microbubble and improve the efficiency of oil removal.

Ship emulsified oil wastewater was used as the research object in this study.     

Dynamics and controllability of droplet fusion under gas–liquid–liquid three-phase flow in a microfluidic reactor

Gas–liquid–liquid three-phase flow systems have unique advantages of controlling reagent manipulation and improving reaction performance. However, there remains a lack of insight into the dynamics and controllability of water droplet fusion assisted by gas bubbles, particularly scaling laws for use in the design and operation of complex multiphase flow processes. In the present work, a microfluidic reactor with three T-junctions was employed to sequentially generate gas bubbles and then fuse two dispersed water droplets. The formation of the dispersed phase was divided into multiple stages, and the bubble/droplet size was correlated with operating parameters. The formation of the second dispersed droplet at the third T-junction was accompanied by the fusion of the two dispersed water droplets that were formed. It revealed a two-stage process (i.e. drainage and fusion) for the two droplets to fuse while becoming mature by breaking-up with the secondary water supply stream. In addition, a droplet contact model was employed to understand the influence on the process stability and uniformity of the merged/fused droplets by varying the surfactant concentration (in oil), the viscosity of the water phase, and the flow rates of different fluids. The study provides a deeper understanding of the droplet fusion characteristics on gas–liquid–liquid three-phase flow in microreactors for a wide range of applications.

Gas–liquid–liquid three-phase flow systems have unique advantages of controlling reagent manipulation and improving reaction performance.     

Mechanism of the evolution of pore structure during the preparation of activated carbon from Zhundong high-alkali coal based on gas–solid diffusion and activation reactions

Zhundong coal can significantly reduce the preparation temperature of activated carbon (AC) due to the high contents of alkali and alkaline earth metals (AAEMs) present in it. Moreover, because of its lower operating temperature and the presence of carbon matrix, Zhundong coal can effectively inhibit the release of AAEM during the preparation of AC. For these reasons, the preparation of AC from Zhundong coal is a promising approach for the clean utilization of Zhundong coal. Accordingly, this study was aimed to investigate optimum conditions for the preparation of AC from Zhundong coal. For this purpose, at first, Raman spectroscopy was used to determine the conditions for an optimal carbonization process using a coal sample; then, the evolution of the pore structure of AC under different conditions was examined by small-angle X-ray scattering (SAXS) and the N₂ adsorption analyser. Furthermore, environmental scanning electron microscopy (ESEM) was performed to analyze the surface morphology of AC. Finally, by dividing the activation process into gas–solid diffusion and activation reactions, a mechanism for the evolution of pore structure during the preparation of AC was proposed. The results showed that the char with an amorphous structure and less graphite-like carbon, which was obtained by heating Zhundong coal from room temperature to 600 °C at 5 °C min⁻¹ under the protection of N₂ and then maintaining it at this temperature for 60 min, is suitable for the subsequent activation process. At low temperatures, the diffusion of H₂O was dominant in the activation process, and the weak gas–solid reaction resulted in poor development of the pore structure; on the other hand, the CO₂ activation reaction mainly occurred on the surface of the char due to the poor diffusion of CO₂, and then, the produced pores could improve the diffusion of CO₂; this led to significant development of the pore structure. With an increase in temperature, the H₂O diffusion reaction was enhanced, and the pore structure of AC was completely developed; however, the diffusion of CO₂ reduced with an enhancement in the CO₂ activation reaction, leading to the consumption of carbon matrix by CO₂ gasification instead of pore formation by the CO₂ activation reaction. Therefore, proper utilization of the unique characteristics of H₂O and CO₂ during pore formation is important to control the activation process.

Decoupled the activation process into gas–solid diffusion and reaction, and revealed an evolution mechanism of pore structure during the preparation of activated carbon.     

Research on the on-line determination of formaldehyde gas by the gas–liquid phase chemiluminescence method

Based on the gas–liquid phase chemiluminescence tester independently developed by our laboratory, a highly sensitive, fast and accurate on-line detection method of formaldehyde gas in ambient atmosphere is established. The chemiluminescence system and the trace formaldehyde gas in the air directly undergo an interface heterogeneous chemiluminescence reaction to obtain a strong chemiluminescence signal. Through the measurement of the chemiluminescence signal intensity, a highly sensitive, real-time and on-line method for the determination of formaldehyde in the air was established. Factors influencing the experimental results such as gallic acid, potassium dichromate, reaction medium concentration, surfactant type and concentration, pump speed, tube length, and interfering gas were discussed based on the single factor and orthogonal analysis results. Finally, the optimal detection conditions were collected, and the detection results were compared with the national standard phenol reagent method. The results show that when the concentration of the standard formaldehyde gas is in the range of 0–0.582 μg L⁻¹, the linear equation of this method is y = 208x + 29.667, the linear coefficient is R² = 0.997, and the minimum detection concentration of formaldehyde is 2.327 × 10⁻³ μg L⁻¹. Under the same external conditions, the comparison and analysis using the national standard phenol reagent method proved that this method has the advantages of fast detection speed, low detection limit, good sensitivity, and accurate results, which can be used for real-time and online determination of trace formaldehyde in ambient air.

Based on the gas–liquid phase chemiluminescence tester independently developed by our laboratory, a highly sensitive, fast and accurate on-line detection method of formaldehyde gas in ambient atmosphere is established.     

Experimental investigation of the dehumidification and decarburization performance of metal–organic frameworks in solid adsorption air conditioning

Solid adsorption air conditioning systems use solid adsorption materials to co-adsorb water vapor and carbon dioxide, allowing the humidity and carbon dioxide concentration in the air-conditioned room to be controlled. Exploring the co-adsorption mechanism of H₂O and CO₂ is essential for the screening of adsorbent materials, system design, and system optimization in solid adsorption air conditioning systems. A fixed-bed adsorption–desorption device was built, and the dynamic adsorption properties of three MIL adsorbent materials MIL-101(Cr), MIL-101(Fe), and MIL-100(Fe) for co-adsorption of H₂O and CO₂ were studied. The results showed that all three MIL adsorbent materials are capable of performing co-adsorption of H₂O and CO₂ and meet the requirements of solid adsorption air conditioning systems. MIL-101(Cr) is recommended for solid adsorption air conditioners where dehumidification is the main focus, while MIL-100(Fe) is recommended for solid adsorption air conditioners where carbon removal is the main focus.

Solid adsorption air conditioning systems use solid adsorption materials to co-adsorb water vapor and carbon dioxide, allowing the humidity and carbon dioxide concentration in the air-conditioned room to be controlled.     

Study on methane hydrate formation in gas–water systems with a new compound promoter

The effects of a new promoter on the growth kinetics of methane hydrates were investigated using a visualized constant-pressure autoclave. The experimental results show that when the 1#, 2# and 3# unit promoter was compounded at a ratio of 2 : 1 : 1, the induction time was shortened greatly from 30 h to 0.64 h compared to the no promoter situation. Meanwhile, there was a larger amount of hydrate formation, and final hydrate volume fraction was 83.652%. Then, the hydrate formation characteristics under different additive dosages (500 ppm, 1000 ppm, 2000 ppm, 5000 ppm) and different subcooling degrees (2.5 °C, 3.5 °C, 4.5 °C, 5.5 °C, 6.5 °C) were investigated. The new promoter at these 4 concentrations could effectively shorten the induction time. And the higher the concentration, the smaller the induction time (0.22 h at 5000 ppm). It was also found that gas consumption and hydrate production rate increased first and then decreased with increasing promoter dosage. Finally, the optimal dosage was determined to be 2000 ppm, at which the induction time was shortened to 0.52 h, and the final hydrate volume fraction was 85.74%. Under the dosage of 2000 ppm and the subcooling degree of 6.5 °C, the shortest induction time (0.29 h) and the maximum formation rate (20.950 ml h⁻¹) were obtained among all the experimental conditions in this work. Moreover, the greater the subcooling degree, the faster the hydrate nucleation, and the shorter the induction time. However, if the subcooling degree was too high, a hydrate layer formed rapidly at the gas–liquid interface in the autoclave, which would hinder hydrate formation and lead to the reduction of hydrate volume fraction to 60.153%. Therefore, a reasonable selection of the proportioning of promoters, dosage of the promoter and formation temperature could significantly promote the formation of hydrates. The findings in this work are meaningful to hydrate associated applications and can provide useful references for the selection of hydrate promoters.

The effects of a new promoter on the growth kinetics of methane hydrates were investigated using a visualized constant-pressure autoclave.     

Influence of water evaporation/absorption on the stability of glycerol–water marbles

The porous shell structure of liquid marbles allows liquid vapor to enter in/out of the liquid marbles, leading to the deformation/collapse of liquid marbles, which limits their application as miniature reactors for long-term chemical reactions. In this study, to prevent volatilization and maintain long-term stability, stable liquid marbles were fabricated by encapsulating glycerol/water droplets using superhydrophobic cellulose nanocrystals. The influence of water evaporation and absorption on the stability of aqueous glycerol marbles at different relative humidities (RHs) was investigated. At the same RH, the evaporation/absorption rates of the liquid marbles decreased on increasing the glycerol concentration. For the liquid marbles with the same glycerol volume concentration, the evaporation rates decreased with the increase in RH. The liquid marbles exhibited higher evaporation/absorption resistance compared with pure naked liquid droplets.

The influence of water evaporation and absorption on the stability of aqueous glycerol marbles was investigated.     

Trajectory of fine particles removal with diffusiophoresis and thermophoresis in a gas–liquid cross-flow array

A gas–liquid cross-flow array (GLCA) system is proposed for fine particles (diameter between 0.1 μm and 2.5 μm, simplified as PM2.5) removal in exhaust gas, where the continuous and smooth wastewater films, providing huge specific surface area, each act as independent traps to remove PM2.5. The removal efficiency of PM2.5 is important for evaluating the performance of a GLCA, and the trajectory across the films determines the migration and ultimate fate of PM2.5. An analytical model based on a single film is developed to analyze the critical removal trajectory with diffusiophoresis (DP) and thermophoresis (TP) in the thermal boundary layer to calculate the efficiency, where the role of each force is examined. And experiments with a lab-scale GLCA are carried out with different vapor concentration and temperature gradients to verify the model. They both reveal that the removal efficiency can be increase sharply by increasing the humidity gradient between the bulk gas and film surface, while it increases slowly as temperature gradient increasing. Thus DP and TP have important effects on PM2.5 removal in the GLCA, and DP has a much more important effect than TP. A GLCA with appropriate humidity and temperature gradient can remove PM2.5 in a costly and efficient manner.

A gas–liquid cross flow array system can significantly improve PM2.5 removal efficiency without additional energy input.     

Anisotropic growth of gas–liquid precipitated ceria mesocrystals to wires several micrometers in length

Ceria (CeO₂) wires with lengths of 6 μm and diameters of tens of nanometers are fabricated through the anisotropic growth of mesocrystals. In the gas–liquid precipitation process, an aqueous Ce(NO₃)₃ solution is used as a starting material and NH₃ gas is used to induce CeO₂ precipitation at the gas–liquid interface. CeO₂ mesocrystals, formed by this process at 60 °C, grow in the direction of 〈011〉 into micrometer length wires exposing {001} and {011} on their side walls. It is shown that the initial pH of the starting material solution is a key parameter to attain anisotropic growth of the CeO₂ mesocrystals. We thus propose the formation mechanism of micrometer length-CeO₂ wires from mesocrystals.

CeO₂ wires several micrometers in length were formed through anisotropic growth of mesocrystals by oriented attachment on {111} surfaces.     

Synthesis of Ni–Ag–ZnO solid solution nanoparticles for photoreduction and antimicrobial applications

ZnO is one of the most promising and efficient semiconductor materials for various light-harvesting applications. Herein, we reported the tuning of optical properties of ZnO nanoparticles (NPs) by co-incorporation of Ni and Ag ions in the ZnO lattice. A sonochemical approach was used to synthesize pure ZnO NPs, Ni–ZnO, Ag–ZnO and Ag/Ni–ZnO with different concentrations of Ni and Ag (0.5%, 2%, 4%, 8%, and 15%) and Ni doped Ag–ZnO solid solutions with 0.25%, 0.5%, and 5% Ni ions. The as-synthesized Ni–Ag–ZnO solid solution NPs were characterized by powdered X-ray diffraction (pXRD), FT-IR spectroscopy, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), UV-vis (UV) spectroscopy, and photoluminescence (PL) spectroscopy. Ni–Ag co-incorporation into a ZnO lattice reduces charge recombination by inducing charge trap states between the valence and conduction bands of ZnO and interfacial transfer of electrons. The Ni doped Ag–ZnO solid solution NPs have shown superior 4-nitrophenol reduction compared to pure ZnO NPs which do not show this reaction. Furthermore, a methylene blue (MB) clock reaction was also performed. Antibacterial activity against E. coli and S. aureus has inhibited the growth pattern of both strains depending on the concentration of catalysts.

The synergic effect of Ni and Ag in Ni–Ag–ZnO solid solutions has tuned the optoelectronic properties of ZnO for photoreduction reactions.     

High voltage,solvent-free solid polymer electrolyte based on a star-comb PDLLA–PEG copolymer for lithium ion batteries

In this work, a novel star-comb copolymer based on poly(d,l-lactide) (PDLLA) macromonomer and poly(ethylene glycol)methyl ether methacrylate (PEGMA) was prepared, and the electrochemical properties were studied, with the aim of using it as a solid polymer electrolyte in lithium ion batteries. The six-arm vinyl functionalized PDLLA macromonomer was synthesized by a ring-opening polymerization (ROP) of d,l-lactide and subsequently an acylation of the hydroxy end-groups. A series of free-standing solid polymer electrolyte membranes from different ratios of PDLLA, PEGMA and LiTFSI were prepared through solvent-free free radical polymerization under UV radiation. The chemical structure of the obtained polymers was confirmed by ¹H NMR and FTIR. The as-prepared six-arm star-comb solid polymer electrolytes (PDLLA-SPEs) exhibit good thermal stability with T_d^5%s of ∼270 °C and low T_gs of −48 to −34 °C. The electrochemical characterization shows that the PDLLA-SPEs possess a wide electrochemical window up to 5.1 V with an optimal ionic conductivity of 9.7 × 10⁻⁵ S cm⁻¹ at 60 °C at an EO/Li⁺ ratio of 16 : 1. Furthermore, the all-solid-state LiFePO₄/Li cells display extraordinary cycling and rate performances at 60 °C by curing the PDLLA-SPEs directly on the cathode. These superior properties of the six-arm star-comb PDLLA-SPE make it a promising candidate solid electrolyte for lithium batteries.

In this work, a novel star-comb copolymer based on PDLLA macromonomer and PEGMA was prepared, and the electrochemical properties were studied, with the aim of using it as a solid polymer electrolyte in lithium ion batteries.     

Preparation of TiO2/porous glass-H with the coupling of photocatalysis oxidation–adsorption system in the initial position and its desulfurization performance on model fuel

TiO₂/porous glass-H as composite catalysts were synthesized hydrothermally in the presence of H₂O₂ using porous glass microspheres as carriers. The photocatalytic-adsorptive desulfurization of model fuel by composite catalysts was investigated under UV irradiation. The structure and morphology of the composite catalysts were characterized via scanning electron microscopy (SEM), N₂ adsorption, X-ray diffraction (XRD) and ultraviolet-visible spectroscopy (UV-vis). The results showed that TiO₂/porous glass-H exhibited a significantly enhanced photocatalytic-adsorption desulfurization performance due to its enhanced surface area, highly enhanced light absorption, and reduced recombination of photogenerated electron pairs compared with TiO₂/porous glass synthesized in the absence of H₂O₂. The optimized TiO₂ loading was 20% and the reaction temperature was 303.15 K, which could achieve almost 100% sulfur removal when 0.1 g catalyst was applied to a sulfide concentration of 300 mg L⁻¹. Based on the kinetic fitting of the obtained data, it was found that the rate-controlling step of sulfide adsorption on the catalyst was a molecular diffusion process and the adsorption intensity and adsorption capacity of the composite catalyst were significantly improved compared with the porous glass-H in the adsorption thermodynamic curve, and ΔS, ΔH and ΔG of the adsorption process were calculated. In addition, TiO₂/porous glass-H could be regenerated via simple heat treatment, exhibiting similar efficiency as the original TiO₂/porous glass-H after three regeneration cycles.

TiO₂/porous glass-H as composite catalysts were synthesized hydrothermally in the presence of H₂O₂ using porous glass microspheres as carriers.     

Inhibition of acid-sensing ion channels reduces the hypothalamus–pituitary–adrenal axis activity and ameliorates depression-like behavior in rats

Depression is the leading cause of disability worldwide, and its treatment represents a major clinical challenge. The hypothalamus–pituitary–adrenal (HPA) axis has been known to play a crucial role in depression and serves as a target for antidepressants. Acid-sensing ion channels (ASICs) are widely expressed in the nervous system and may be implicated in depression. Whether ASICs could act on the HPA axis to affect depression-related behaviors is not fully understood. In this study, we investigated the effect of inhibition of ASICs on the HPA axis activity in chronic stress-subjected rats. We found that treatment with the ASIC selective antagonist amiloride reversed chronic stress-induced elevation of adrenocorticotropic hormone (ACTH) and corticosterone in serum, which is reflective of the HPA axis activity. In addition, amiloride also alleviated chronic stress-induced anhedonia-like behavior. These results suggest that inhibition of ASICs may act on the HPA axis to alleviate the symptoms of depression.

Depression is the leading cause of disability worldwide, and its treatment represents a major clinical challenge.     

Effect of unmelted lime on the element distribution behavior on a CaO–SiO2–MgO–Al2O3–FeO–CaF2(–Cr2O3) slag

In this study, a CaO–SiO₂–Al₂O₃–MgO–FeO–CaF₂(–Cr₂O₃) slag was chosen according to the compositions of the stainless steel slag for industrial production, and a CaO block was added to the molten slag after the synthetic slag was fully melted. The influences of unmelted lime on the distribution of elements and the structure of product layers at the lime/slag boundary, particularly the existing state of chromium oxide in the chromium-bearing stainless steel slag, were deeply discussed by scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) and FactSage 7.1. The experiment results indicated that when the unmelted lime existed in the CaO–SiO₂–Al₂O₃–MgO–FeO–CaF₂ slag system, two product layers of periclase (MgO) and dicalcium silicate (Ca₂SiO₄) at the boundary of the CaO block were formed. However, when the CaO block was added in the CaO–SiO₂–Al₂O₃–MgO–FeO–CaF₂–Cr₂O₃ stainless steel slag, besides MgO and Ca₂SiO₄ product layers, needle-shaped calcium chromite (CaCr₂O₄) was also precipitated around the CaO block. Moreover, a small amount of Cr dissolved in the periclase phase. Eh–pH diagrams showed that the CaCr₂O₄ and MgO phase unstably existed in a weak acid aqueous solution. Therefore, the existence of unmelted lime in the stainless steel slag could enhance the leachability of chromium.

The effect of unmelted lime on the distribution of elements and structure of product layers in CaO–SiO₂–MgO–Al₂O₃–FeO–CaF₂(–Cr₂O₂) stainless steel slag and the action of unmelted lime phase mechanism in experimental slags was conducted.     

Copper–ligand clusters dictate size of cyclized peptide formed during alkyne–azide cycloaddition on solid support

Peptide and peptidomimetic cyclization by copper-catalyzed alkyne–azide cycloaddition (CuAAC) reaction have been used to mimic disulfide bonds, alpha helices, amide bonds, and for one-bead-one-compound (OBOC) library development. A limited number of solid-supported CuAAC cyclization methods resulting in monomeric cyclic peptide formation have been reported for specific peptide sequences, but there exists no general study on monocyclic peptide formation using CuAAC cyclization. Since several cyclic peptides identified from an OBOC CuAAC cyclized library has been shown to have important biological applications, we discuss here an efficient method of alkyne–azide ‘click’ catalyzed monomeric cyclic peptide formation on a solid support. The reason behind the efficiency of the method is explored. CuAAC cyclization of a peptide sequence with azidolysine and propargylglycine is performed under various reaction conditions, with different catalysts, in the presence or absence of an organic base. The results indicate that piperidine plays a critical role in the reaction yield and monomeric cycle formation by coordinating to Cu and forming Cu–ligand clusters. A previously synthesized copper compound containing piperidine, [Cu₄I₄(pip)₄], is found to catalyze the CuAAC cyclization of monomeric peptide effectively. The use of 1.5 equivalents of CuI and the use of DMF as solvent is found to give optimal CuAAC cyclized monomer yields. The effect of the peptide sequence and peptide length on monomer formation are also investigated by varying either parameter systemically. Peptide length is identified as the determining factor for whether the monomeric or dimeric cyclic peptide is the major product. For peptides with six, seven, or eight amino acids, the monomer is the major product from CuAAC cyclization. Longer and shorter peptides on cyclization show less monomer formation. CuAAC peptide cyclization of non-optimal peptide lengths such as pentamers is affected significantly by the amino acid sequence and give lower yields.

We report the heterogeneous controlled formation of monomeric cyclic peptides by CuAAC reaction using cooper–piperidine complexes.     

Degradation and mechanism analysis of chloroxylenol in aqueous solution by gas–liquid discharge plasma combined with ozonation

Gas–liquid discharge non-thermal plasma (NTP) coupled with an ozonation reactor was used to investigate the removal of a broad-spectrum antibacterial agent, chloroxylenol (PCMX), from aqueous solution. Under the same experimental conditions (discharge power of 50.25 W, the initial concentration of PCMX of 60 mg L⁻¹, oxygen flow of 1.0 L min⁻¹ and PCMX solution flow of 150 mL min⁻¹), the PCMX degradation rates in the ozonation-only, NTP-only and NTP/O₃ systems were 29.25%, 67.04% and 79.43%, respectively. Correspondingly, the energy efficiency has also been greatly improved, and increased to 0.45, 1.03 and 1.21 g kW⁻¹ h⁻¹. In addition, the effects of the initial concentration of PCMX, initial pH, the flow rate of oxygen, the addition of H₂O₂ and the addition of a radical scavenger on the degradation rate of PCMX were investigated in the NTP/O₃ system. The degradation rate in acidic solutions was higher than that in alkaline solutions. During the removal process of PCMX, the rate of degradation was strongly increased with the addition of H₂O₂ and acutely decreased with the addition of the radical scavenger. Compared with deionized water the degradation rates of PCMX in secondary effluent were inhibited. Four main intermediates of PCMX degradation by the NTP/O₃ system were identified by gas chromatography-mass spectrometry (GC-MS) and a possible degradation pathway of PCMX was proposed. The changes in toxicity of the PCMX solution during the NTP/O₃ system oxidation process were also evaluated using bioluminescent bacteria and Quantitative Structure Activity Relationship (QSAR) models with the help of the ECOSAR software.

Gas–liquid discharge non-thermal plasma (NTP) coupled with an ozonation reactor was used to investigate the removal of a broad-spectrum antibacterial agent, chloroxylenol (PCMX), from aqueous solution.     

Deposition of methylammonium iodide via evaporation – combined kinetic and mass spectrometric study

Methylammonium lead halide perovskites have recently emerged as a very attractive and versatile material for solar cell production. Several different perovskite fabrication methods can be used though most of them involve either spin coating, evaporation under high vacuum or a combination hereof. In this study we focus on thermal evaporation of methylammonium iodide (MAI), or more specifically, why this process, in terms of a physical vapour deposition, requires such a high deposition pressure to be successful. We use quartz crystal micro balance (QCM) measurements as well as mass spectrometry. The results indicate that MAI has a very low sticking especially if the substrate is held at elevated temperatures and is furthermore observed to evaporate with disproportionation into primarily CH₃NH₂ and HI. Even when PbCl₂ is deposited on the QCM crystal, so that CH₃NH₃PbI_(3−x)Cl_x perovskite can form, the MAI sticking remains low, possibly due to the requirement that both species be present on the film surface at the same time to form the perovskite. The results provide guidelines for designing a perovskite deposition chamber and additionally fundamental information about MAI evaporation.

Methylammonium iodide (MAI) is found to evaporate as CH₃NH₂ and HI with the result that a high partial pressure of MAI is needed to form CH₃NH₃PbI_(3−x)Cl_x perovskite under vacuum conditions.     

Coordination complexes constructed from pyrazole–acetamide and pyrazole–quinoxaline: effect of hydrogen bonding on the self-assembly process and antibacterial activity

Two mononuclear coordination complexes of N-(2-aminophenyl)-2-(5-methyl-1H-pyrazol-3-yl)acetamide (L₁), namely [Cd(L₁)₂Cl₂] (C₁) and [Cu(L₁)₂(C₂H₅OH)₂](NO₃)₂ (C₂) and one mononuclear complex [Fe(L₂)₂(H₂O)₂](NO₃)₂·2H₂O (C₃), obtained after in situ oxidation of L₁, have been synthesized and characterized spectroscopically. As revealed by single-crystal X-ray diffraction, each coordination sphere made of two heterocycles is completed either by two chloride anions (in C₁), two ethanol molecules (in C₂) or two water molecules (in C₃). The crystal packing analysis of C₁, C₂ and C₃, revealed 1D and 2D supramolecular architectures, respectively, via various hydrogen bonding interactions, which are discussed in detail. Furthermore, evaluation in vitro of the ligands and their metal complexes for their antibacterial activity against Escherichia coli (ATCC 4157), Pseudomonas aeruginosa (ATCC 27853), Staphylococcus aureus (ATCC 25923) and Streptococcus fasciens (ATCC 29212) strains of bacteria, revealed outstanding results compared to chloramphenicol, a well-known antibiotic, with a normalized minimum inhibitory concentration as low as 5 μg mL⁻¹.

Two mononuclear coordination complexes of N-(2-aminophenyl)-2-(5-methyl-1H-pyrazol-3-yl)acetamide (L₁) and one mononuclear complex, obtained after in situ oxidation of L₁, have been synthesized and characterized spectroscopically.