Amount Of Hydroxide Research Articles

Optimization of MOFs-induced strategy for preparing anatase-free hierarchical TS-1 towards 1-hexene epoxidation: TPAOH dosage regulation, silanization and stabilizing acidic sites

Metal organic frameworks (MOFs)-induced synthetic strategy has been proven a convenient and efficient way for preparing anatase-free hierarchical TS-1 zeolite in our previous study. Here, to further enhance the catalytic performance on 1-hexene, the MOFs-induced hydrothermal synthesis route is optimized by adjusting the amount of tetrapropylammonium hydroxide (TPAOH) and performing different degrees of silanization treatment. A low TPAOH dosage can ensure the synthesized samples have abundant and dense active framework Ti at the expense of partial hierarchical structure. Further deep silanization treatment created mesoporous structure ranging between 20 and 30 nm without affecting the content or distribution of active titanium. The obtained anatase-free hierarchical TS-1 sample Sil-0.150 possesses excellent 1-hexene conversion of >38%. Based on detailed NH3-TPD and Py-IR tests, the presence of high-density Lewis acid sites (LAS) leads to a decreased epoxy product selectivity of 91.5%, and the optimized MOFs-induced synthesis strategy may open up new perspectives for the design and application of high-performance TS-1 catalysts in selective epoxidation reactions of various alkenes.

Study on preparation and properties of alkali-free accelerator

As one of the main components of shotcrete, accelerator is widely used in housing construction, tunnel engineering and road emergency repair. In this paper, hydrofluoric acid, aluminum sulfate and aluminum hydroxide were used as main raw materials to prepare alkali free accelerator by liquid phase self reaction method. The influence of the amount of hydrofluoric acid, aluminum sulfate and aluminum hydroxide on the coagulation performance and stability of alkali free accelerator was mainly investigated. The test results are as follows: within the experimental range, the influence of aluminum sulfate on the coagulation performance of alkali free accelerator is greater than that of hydrofluoric acid. When the amount of 40% hydrofluoric acid is 100 g ∼ 160g, the amount of aluminum hydroxide is 50 g ∼ 80g, and the amount of aluminum sulfate is 320 g ∼ 400g, the alkali free accelerator products with main indexes of initial setting time ≤ 3 min and final setting time ≤ 6 min can be prepared, which meet the requirements of GB/T 35159-2017"Accelerator for shotcrete". The unit price of the optimized product is ¥1488 which is compared with the main products on the market, This product has good competitiveness.

Study on Efficient Degradation of Waste PU Foam.

In this paper, the high-efficiency degradation and alcoholysis recovery of waste polyurethane foam were realized using a combination of a high-efficiency alkali metal catalyst (CsOH) and two-component mixed alcoholysis agents (glycerol and butanediol) in different proportions, using recycled polyether polyol and one-step foaming to prepare regenerated thermosetting polyurethane hard foam. The foaming agent and catalyst were adjusted experimentally to prepare regenerated polyurethane foam, and a series of tests were conducted on the viscosity, GPC, hydroxyl value, infrared spectrum, foaming time, apparent density, compressive strength, and other properties of the degradation products of the regenerated thermosetting polyurethane rigid foam. The resulting data were analyzed, and the following conclusions were drawn: The optimal conditions of alcoholysis were obtained when the mass ratio of glycerol to butanediol was 3:2, the amount of cesium hydroxide was 0.08%, the reaction temperature was 170 °C, and the reaction time was 2.5 h. Regenerated polyurethane foam with an apparent density of 34.1 kg/m3 and a compressive strength of 0.301 MPa was prepared under these conditions. It had good thermal stability, complete sample pores, and a strong skeleton. At this time, these are the best reaction conditions for the alcoholysis of waste polyurethane foam, and the regenerated polyurethane foam meets various national standards.

In situ synthesis of ferrate based on calcium hypochlorite for organic matter removal

Ferrate is a promising environment-friendly water-treatment agent due to its multiple function. However, its large-scale application in sewage treatment is limited because of its instability in aqueous solution and the high cost of pure ferrate. This study demonstrated an improved wet oxidation process for synthesising ferrate by oxidising ferric with calcium hypochlorite (Ca(ClO)2). The effects of reagent dosage and temperature on ferrate (VI) were investigated. The optimum conditions for ferrate (VI) synthesis was obtained (1 g of calcium hypochlorite, 5 g of sodium hydroxide (NaOH) and 4 g of iron (III) chloride (FeCl3) in 25 ml of water at 20°C and stirring for 30 min). Under the optimum conditions, the available chlorine and sodium hydroxide amount was about one-fifth and one-half of that of traditional sodium hypochlorite oxidation, respectively. The product was characterised by ultraviolet–visible spectroscopy and X-ray photoelectron spectroscopy. It was concluded that ferrate was present in the generated ferrate solution. Low-temperature, airtight and shading conditions and the addition of sodium silicate are conducive to the preservation of fresh ferrate. At pH 5.0, fresh ferrate could effectively remove methylene blue (MB) and chlorpyrifos in water, and the average removal rate of MB or chlorpyrifos was about 55% higher than that by pure ferrate.

Interzeolite transformation from H+-type FAU zeolite into pure CHA zeolite via OSDA/seeds-free and steam-assisted conversion process

Pure CHA zeolite was transformed from FAU zeolite via organic structure-directing agent (OSDA)/seeds-free steam-assisted conversion (SAC). CHA zeolite was transformed using H+-type FAU zeolite with a low Si/Al ratio (Si/Al = 2.8) and a small amount of potassium hydroxide (KOH) and H2O. The Si/Al ratio of the CHA zeolite of the final product was the same as that of FAU-type zeolite as raw material because OH− ions derived from KOH reacted with H+ ions in FAU zeolite. Then, Si constituting FAU zeolite was little dissolved in a small amount of the basic solvent during the interzeolite transformation process. In general, in the interzeolite transformation process, the Si/Al ratio of the final product is lower than that of zeolite as raw material due to the dissolution of Si in the framework in the basic solvent. However, the interzeolite transformation process in this study can reduce the dissolving Si ratio using H+-type FAU zeolite. In addition, the PHI framework with low CO2 adsorption capacity arose with CHA zeolite transformed from Na+-type FAU zeolite via OSDA-free interzeolite SAC in a previous study. However, in this study, the PHI framework did not arise in OSDA-free steam-assisted interzeolite transformation process due to the use of H+-type FAU zeolite. Furthermore, the second particle morphology of CHA zeolite transformed from H+-type FAU zeolite was spherical, which has not been seen in CHA zeolite particles synthesized in previous reports. Finally, the CO2 adsorption capacity and performance of FAU and CHA zeolites were measured. CHA zeolite showed higher CO2 adsorption capacity than H+-type FAU zeolite as the starting material and high CO2 loadings at low CO2 equilibrium pressure. This study investigated that the synthesis condition, chemical properties, and CO2 adsorption performance of CHA zeolite transformed from H+-type FAU zeolite via the OSDA/seeds-free steam-assisted interzeolite transformation process.

The Effect of Biological Corrosion on the Hydration Processes of Synthetic Tricalcium Aluminate (C3A)

This paper presents a study related to the biological degradation of a tricalcium aluminate (C3A) phase treated with reactive media from the agricultural industry. During one month of setting and hardening, synthetic C3A was subjected to corrosion in corn silage, pig slurry and chicken manure. The hardening process of the C3A phase in water was used as a reference sample. The phase composition and microstructure of the hydrating tricalcium aluminate slurries were characterised by X-ray diffraction (XRD), thermal analysis (DTA/TG/DTG/EGA), scanning microscopy (SEM, EDS) and infrared spectroscopy (FT-IR). In the samples studied, it was observed that the qualitative and quantitative phase composition of the synthetic tricalcium aluminate preparations changed depending on the corrosion exposure conditions. The main crystalline phases formed by the hydration of the examined samples in water as well as in corrosive media were the catoite (Ca3Al2(OH)12) and hydrocalumite (Ca2Al(OH)7·3H2O) phases. Detailed analysis showed the occurrence of secondary crystallisation in hydrating samples and the phases were mainly calcium carbonates (CaCO3) with different crystallite sizes. In the phase composition of the C3A pastes, varying amounts of aluminium hydroxides (Al(OH)3) were also present. The crystalline phases formed as a result of secondary crystallisation represented biological corrosion products, probably resulting from the reaction of hydrates with secondary products resulting from the metabolic processes of anaerobic bacterial respiration (from living matter) associated with the presence of bacteria in the reaction medium. The results obtained contribute towards the development of fast-acting and bio-corrosion-resistant special cements for use in bioenergetics.

Features of assessing the intestinal barrier permeability in chronic kidney disease

Numerous studies have shown that changes in the intestinal microbial-tissue complex are a risk factor for the progression of chronic kidney disease (CKD) to end-stage renal disease and, therefore, a potential target for new therapeutic interventions. Thus, reliable and sensitive diagnostic tools for measuring intestinal permeability in the clinical setting are necessary. Modern genome sequencing and multi-omics technologies have established that patients with CKD are characterized by a specific imbalance between the saccharolytic and proteolytic microbiota, contributing to the accumulation of numerous toxic microbial products, such as indoxyl sulphate, p-cresyl sulphate, trimethylamine-N-oxide. Progressive kidney function decline leads to compensatory urea accumulation in the gastrointestinal tract. In the intestinal lumen, urea is hydrolyzed by microbial urease, forming a large amount of ammonium hydroxide, which may be accompanied by disruption of the epithelial barrier integrity with an increase in intestinal permeability for microbial molecules that initiate systemic inflammation. Experimental approaches to studying the intestinal barrier in CKD include the assessment of electrophysiological parameters of the intestinal epithelium and the transport of fluorescently labelled tracers in the Ussing chamber. Actively improving various cell-based in vitro methods, which may be useful for studying the effect of microbiota on the barrier functions of the intestinal epithelium. Gene expression and protein content of tight junctions are estimated using polymerase chain reaction, immunohistochemical methods and Western blotting. Using various biomolecular methods, it was found that renal failure is characterized by the presence of inflammatory and atrophic changes throughout the gastrointestinal tract, destruction of the mucin layer, damage to tight junctions with a decrease in the amount of claudine-1, occludin and ZO-1 as well as a decrease in transepithelial electrical resistance. Clinical examination of intestinal permeability by methods based on the urine excretion of orally administered sugars, polyethylene glycol polymers and labelled tracers indicate a distortion of the results in patients with CKD due to altered renal clearance. Alternatively, quantitative determination of bacterial DNA and D-lactate levels in the blood is considered. Identification of serum non-coding microRNAs, confocal laser endomicroscopy and impedance spectroscopy have the potential to be used as methods for assessing intestinal barrier function.

Studies on the effects of highenergy electron beam irradiation on the Mechanical properties of Magnesium hydroxide filled HDPE/Mg(OH)2/TCA-27 composites

The effect of irradiation electron beam at dose of 150 kGy,on the mechanical properties of
 high density polyethylene (HDPE) mixed with various amounts of magnesium hydroxide (Mg(OH)2) composites as filler have been studied here. It has been found that the highenergy electron beam irradiation has much effect on the mechanical properties of the
 HDPE/Mg(OH)2/TCA-27 composites. The tensile strength and elastic modulus are increased greater than the unirradiated ones. Meanwhile, the increasing content of the Mg(OH)2 in composites. The structure of the SEM of the unirradiated HDPE/ Mg(OH)2/TCA-27 shows poorly mechanical properties of compositeswhich are compared to irradiated ones. The Comparison of properties of composites filled with irradiated and unirradiated Magnesium hydroxide establishes than irradiated of Magnesium hydroxide which imparts better reinforcing properties than unirradiated filler of composites. The properties under consideration are tensile strength, (%) elongation at break, elastic modulus, hardness . Tensile strength isimproved by 6.67% , elastic modulus is improved by 42.86%, while hardness is improved by 0.85%, at ( 0.37 ) volume fraction .

Synthesis of novel and tunable Micro-Mesoporous carbon nitrides for Ultra-High CO2 and H2S capture

Carbon nitride (CN) materials with intrinsic high nitrogen content are potential candidates for acidic gas adsorption. However, these nanomaterials should be further treated to achieve tunable textural properties for ultra-high gas adsorption. Herein, we synthesized dual-pore carbon nitride materials (DP-CN) with a series of ethylenediamine to carbon tetrachloride ratios with different amounts of potassium hydroxide (KOH) as a chemical activator using nanosilica (SiO2) as a hard template to tune the physicochemical properties of the materials. The prepared DP-CN adsorbents had a large surface area (up to 2036.9 m2/g), great pore volume (up to 1.15 cm3/g), and high nitrogen content (10.6 to 15.1 wt%). The best DP-CN displayed ultra-high CO2 and H2S adsorption capacity at 1 bar (8.3 and 13.8 mmol/g, respectively), 10 bar (16.9 and 23.1 mmol/g, respectively), and 30 bar (22.9 mmol/g for CO2) at 25 °C, which was significantly higher than those of other pure mesoporous carbon nitrides (M-CN) and carbon-based adsorbents. Moreover, the best adsorbent exhibited good CO2/N2, CO2/CH4, H2S/N2, and H2S/CH4 selectivity, suitable heat of adsorption, and excellent cyclic stability. According to density functional theory calculations, H2S adsorbs more strongly than CO2 on carbon nitride surfaces, and the adsorption energies of CO2 and H2S are related to charge-transfer values from the surface to the adsorbed species. The results revealed that the exceptional textural properties and high nitrogen content of the materials could play the main role in the superior adsorption of CO2 and H2S. This generation of CN materials is expected to be practical for a various range of separation processes, catalysis, capacitors, and energy storage.

Structural Characterization and Optimization of a Miconazole Oral Gel.

The development of semisolid formulations, gels in particular, has raised the attention of scientists more and more over the last decades. Because of their biocompatibility, hydrophilic nature, and capacity of absorbing large quantities of water, hydrogels are still one of the most promising pharmaceutical formulations in the pharmaceutical industry. The purpose of this study is to develop an optimal formulation capable of incorporating a water-poorly soluble active ingredient such as miconazole used in the treatment of fungal infections with Candida albicans and Candida parapsilosis. A D-optimal design was applied to study the relationship between the formulation parameter and the gel characteristics. The independent parameters used in this study were the Carbopol 940 concentration (the polymer used to obtain the gel matrix), the sodium hydroxide amount, and the presence/absence of miconazole. Ten different dependent parameters (Y1-Y10) were evaluated (penetrometry, spreadability, viscosity, and tangential tension at 1 and 11 levels of speed whilst destructuring and during the reorganization of the gel matrix). The consistency of the gels ranged from 23.2 mm (GO2) to 29.6 mm (GM5). The least spreadable gel was GO7 (1384 mm2), whilst the gel that presented the best spreadability was GO1 (3525 mm2). The viscosity and the tangential stress at the selected levels (1 and 11) varied due to the different compositions of the proposed gels. The gels were also tested for drug content and antifungal activity. All determinations had satisfying results; the drug content was within limits accepted by Ph. Eur. 10 and all formulations containing miconazole exhibited antifungal activity. An optimal formulation with miconazole was attained, consisting of 0.84% Carbopol 940 and 0.32% sodium hydroxide.

Improving recycled concrete aggregates using flue gas based on multicyclic accelerated carbonation: Performance and mechanism

Utilizing flue gas from cement plants to treat the recycled concrete aggregates (RCAs) through accelerated carbonation is a new strategy for reducing carbon emission and improving the quality of RCAs. However, due to the low CO2 concentration, carbonation efficacy is always unsatisfactory. In this study, multicyclic carbonation treatment was performed to enhance the carbonation efficacy using flue gas as CO2 source. The key operation parameters including carbonation duration, gas pressure and cycle numbers were optimized, and the carbonation performance and mechanisms were evaluated. Results showed that treating the RCAs for six cycles within 24 h at gas pressure of 0.1 MPa could obtain satisfactory carbonation percentage. Microstructure analysis verified that, after multicyclic carbonation, large amount of calcium hydroxides were converted into calcium carbonates to reduce the porosity and promote the quality of RCAs. Furthermore, compared with non-carbonated recycled aggregate concrete, the compressive strength and flexural strength of concrete incorporating RCAs treated by flue gas increased by 25.2 % and 26.5 %, respectively. The present study proposes an innovative approach for improving the carbonation efficacy of flue gas as CO2 source.

Development of biocompatible and corrosion-resistant plasma electrolytic oxidation coating over zinc for orthopedic implant applications

The potential use of zinc in biomaterials is immense and lies unexplored to a greater extent. The recent research on zinc indicates the possibility of utilising zinc as a biodegradable biomaterial. Zinc-based materials with reduced corrosion rates in biological media may enable them as temporary orthopedic implant applications. This work aims to develop a biocompatible and corrosion-resistant plasma electrolytic oxidation (PEO) based coating over zinc. Different PEO coatings were fabricated on zinc in electrolyte systems consisting of various percentages of sodium meta silicate and borax decahydrate (75:25, 50:50, and 25:75) and a fixed amount of potassium hydroxide. After the successful fabrication of the PEO coating over the zinc, its morphological features, coating adhesion strength, wettability, corrosion resistance, and, most importantly, cytotoxicity is examined. The coating was peeled off on sample PEO treated with silicate to the borax decahydrate ratio of 75:25. In contrast, higher coating thickness, good corrosion and scratch resistance without any peeling were observed for the samples with silicate to borax decahydrate ratios of 50:50 and 25:75. Meanwhile, the cytotoxicity tests showed that the sample coated in the electrolyte comprised of an equal proportion of silicate and borax decahydrate (50:50) is better than the one coated in silicate: borax decahydrate ratio of 25:75, due to its favourable chemical composition, roughness, and wettability. Considering the physicochemical properties and biocompatibility, it can be concluded that the Zn PEO treated with silicate and borax decahydrate (50:50) is the appropriate candidate material for orthopedic applications.

Chemical and Mineralogical Characterization of Montevive Celestine Mineral

The Montevive celestine mineral deposit, set in the Granada Basin in a marine evaporitic uppermost Tortonian–lowermost Messinian sequence, is the largest reserve in Europe of this economically important strontium ore. Currently, the mine has a large amount of tailings resulting from the rejection of a manual dry screening of high-grade celestine mineral. This visual and density screening was carried out in the early days of mining (1954–1973). Concentrating the celestine mineral and increasing the ore recovery rate would reduce mine operation costs and the generation of new tailings, reducing the impact on the environment. In order to define more adequate concentration methods, we have used complementary analytical techniques such as optical (OM) and scanning and transmission electron microscopy (SEM and TEM), energy-dispersive X-rays (EDXs), X-ray fluorescence (XRF), and X-ray diffraction (XRD) to fully characterize the morphology, microstructure, chemistry, and mineralogy of the celestine mineral. The low-grade mineral is made of prismatic celestine crystals that are replacing a matrix of micro sparry calcite. Other minority minerals are strontianite, dolomite, quartz, and clays (kaolinite, paragonite, and illite). There is also a certain amount of iron oxides and hydroxides (mainly magnetite) associated with clays. We showed that the concentration of low-grade celestine mineral can be achieved through a low-cost and eco-friendly method based on grinding and size separation. The coarser fractions (>5 mm) have more celestine (up to 12 percent units higher than the starting unprocessed mineral) due to the selective loss of calcite and minority minerals (quartz, clays, and iron oxides) that are mainly found in the finer fraction (<1 mm). This process can make mine exploitation more sustainable, reducing the generation of residues that negatively impact the environment.

Copper oxide nanostructures: Preparation, structural, dielectric and catalytic properties

A convenient chemical precipitation route was applied to prepare cupric oxide nanoparticles using copper acetate as precursor material. The influence of the reaction conditions on the formation of CuO nanoparticles was studied. The particle size of cupric oxide varies between 7.79 and 23.83 nm depending on the sodium hydroxide amount. The crystallite size of CuO nanoparticles obtained by electrospinning and calcination was of 42.25 nm. X-ray diffraction, scanning electron microscopy, EDX, XPS, electronic absorption and emission spectra were used to discuss the structural, morphological and optical properties of the CuO nanostructures. The electrical characteristics of CuO nanoparticles were investigated by dielectric and conductivity measurements. The dielectric constant ( ε ′) and loss ( ε ’’) were found to be decreased as the frequency increased. The photocatalytic activity of CuO nanoparticles was investigated following the degradation of ciprofloxacin.

Crevice Corrosion Behavior of Alloy 690 in High-Temperature Aerated Chloride Solution.

Crevice corrosion behavior of Alloy 690 in high-temperature aerated chloride solution was studied using a self-designed crevice device. The SEM, EDS, XRD, and XPS analyses results indicated that the oxide films outside the crevice consisted of Ni-Cr oxides containing a small amount of hydroxides, and the oxide films on crevice mouth consisted of a (Ni,Fe)(Fe,Cr)2O4 spinel oxides outer layer and a Cr(OH)3 inner layer, and the oxide films inside the crevice consisted of a α-CrOOH outer layer and a Cr(OH)3 inner layer. When crevice corrosion occurred, the hydrolysis of Cr3+ led to the formation of Cr(OH)3 inside the crevice, and caused the pH value of crevice solution to decrease, and Cl− migrated from outside the crevice into inside the crevice due to electrical neutrality principle and accumulation. When the water chemistry inside the crevice reached the critical value of active dissolution of metal, the active dissolution of metal inside the crevice occurred. In addition, (Ni,Fe)(Fe,Cr)2O4 spinel oxides on the crevice mouth were formed by the deposition of metal ions migrated from inside the crevice. The mechanism of crevice corrosion and the formation mechanism of oxide films at different regions were also discussed.

Innovative In Vitro Strategy for Assessing Aluminum Bioavailability in Oral Care Cosmetics.

Aluminum is an element found in nature and in cosmetic products. It can interfere with the metabolism of other cations, thus inducing gastrointestinal disorder. In cosmetics, aluminum is used in antiperspirants, lipsticks, and toothpastes. The aim of this work is to investigate aluminum bioavailability after accidental oral ingestion derived from the use of a toothpaste containing a greater amount of aluminum hydroxide than advised by the Scientific Committee on Consumer Safety (SCCS). To simulate in vitro toothpaste accidental ingestion, the INFOGEST model was employed, and the amount of aluminum was measured through the ICP-AES analysis. Tissue barrier integrity was analyzed by measuring transepithelial electric resistance, and the tissue architecture was checked through light microscopy. The margin of safety was also calculated. Overall, our results indicate that the acute exposure to aluminum accidentally ingested from toothpastes is safe for the final user, even in amounts higher than SCCS indications.

Synthesis of Isoindoline-1,3-Dione Derivatives as Cyclooxygenase (Cox) S Inhibitors

Inflammation is the vital part of the immune system's response to injury and infection. It is the body's way of signaling the immune system to heal and repair damaged tissue. The objective of this paper is to design and synthesize a new isoindoline 1,3-dinoe derivative and investigate their selective anti inflammatory activity to COXs. As a potential anti-inflammatory compound, Isoindoline-1,3-dione derivatives were synthesized from the addition reaction of phthalimide, formaldehyde, catalytic amount of potassium hydroxide and cyclic amine in ethanol yielded the desired Isoindoline-1,3-dione compounds (ZJ1-ZJ6. 1H- NMR, ¹³C-NMR, FT-IR and elemental analysis were consistent with the assigned structures. Isoindoline-1,3-dione derivatives exhibited good inhibitory activity against the COX enzymes. To explain the result of our investigation to COX-1 and COX-2 and the selectivity of our compounds to either COX-1 or COX-2, the rationalization in COX-1, the amino group participate more effectively in binding with the ligand while in COX-2, the aryl group is more effective in binding to the ligand. The amino acetylenic compounds behave differently toward COXs from our compound. ZJ4 have shown some selective COX-1 ligand efficiency while ZJ1 promised a potent blockage and ligand efficiency toward the COX-2 enzyme which was found to be higher than the marketed drug Indomethacin and near potency score of Celecoxib. For the first time, this indicates the requirement of investigating the removal of acetylenic group in this study showed that it might be a different binding site in COXs which may result in effective compounds.

Participation of alkali and sulfur in ammonia combustion chemistry: Investigation for ammonia/solid fuel co-firing applications

Ammonia (NH3) is a promising carbon-free energy carrier. Co-firing of ammonia in solid fuel-fired facilities is a feasible solution to reduce carbon dioxide (CO2) emissions. Solid fuels, such as coal and biomass, contain various trace elements, such as alkali metals and sulfur, which are released to the gas phase during combustion. Experimental characterization and modeling are used to study the participation of alkali and sulfur species in ammonia conversion in a post-flame environment, focusing on the characteristics of NO emissions and NH3 slip. The combustion environment was provided by a laminar flame burner with a temperature decreasing from about 2000 K in reaction zone to 1500 or 1100 K in flue gas zone and an equivalence ratio of around 0.65 or 1.3. Known amounts of ammonia (up to 20,000 ppm), potassium hydroxide (KOH, representative of alkaline substances, up to 25 ppm), and sulfur dioxide (SO2, up to 1500 ppm) were uniformly introduced into the burner for high-temperature thermochemical research. The concentrations of NH3, nitric oxide (NO), KOH, SO2, and hydroxyl radicals (OH) downstream of the burner were measured quantitatively in situ using broadband UV (ultraviolet) absorption spectroscopy. In the oxidizing reaction environments, the influence of SO2 on the NO formation was negligible, while KOH significantly reduced the concentration of NO, and even led to residual ammonia in the low temperature case. Under reducing conditions, both SO2 and KOH significantly inhibited the decomposition of ammonia, especially at relatively low temperature. Meanwhile, consumption of KOH/K was observed after the mixing with ammonia, possibly due to a direct reaction of KOH/K with ammonia. One dimensional modeling using a detailed mechanism containing N/S/K chemistry qualitatively predicted the impact of S/K on ammonia oxidation and decomposition. The effect was mainly contributed to the enhanced radical consumption by SO2 and KOH. However, the model could not describe the observed consumption KOH/K by ammonia. Potassium amide (KNH2) can be generated through KOH + NH3 = KNH2 + H2O. However, according to quantum chemistry calculations for KNH2, this reaction is endothermic by 80 kJ mol−1, shifting the equilibrium strongly towards KOH + NH3, and more work is required to clarify the mechanism of removal of potassium by NH3.

Structural variety, fluorescence and photocatalytic activity of dissymmetric thiosemicarbazone complexes

A new dissymmetric bis(thiosemicarbazone) ligand, H2L2, containing a 4-(1-naphthyl)-3-thiosemicarbazone branch has been easily prepared and characterized. The reactivity of this ligand and the hybrid isopropylthiosemicarbazone/naphtoylhydrazone, H2L1, with zinc(II), copper(II) and nickel(II) nitrates in the presence of different amounts of lithium hydroxide has been explored. The results show that although both ligands present two different acidic protons, the degree of deprotonation of the ligand cannot be selectively controlled, since in almost all the reactions carried out without base the ligand is at least singly deprotonated. Nevertheless, an interesting structural diversity is found, also influenced by the metal structural preferences, leading to the formation of monomeric (1–5, 8 and 9), dimeric (6) and polymeric (7) species. The different degree of deprotonation of the ligands, together with the presence or the absence of nitrate ions and solvent molecules, lead to the formation of different supramolecular architectures based on different hydrogen bond arrays. Fluorescence spectroscopy in the solid state for the ligands and the complexes was performed and the results show that whereas H2L1 is fluorescent, for H2L2 no fluorescence emission was detected. Complexation of H2L1 leads, in general, to a quench of the fluorescence emission, except for complex [ZnL1(EtOH)] 2, which is much more fluorescent than the free ligand. Conversely, complexation of H2L2 with zinc(II) causes fluorescence emission. Photocatalytic experiments with the nickel and copper complexes shows that the four complexes can effectively degrade methyl orange under UV–vis irradiation.

Ingenious synthesis of chitosan-based porous carbon supercapacitors with large specific area by a small amount of potassium hydroxide

Chitosan has been widely studied in the preparation of carbon-based supercapacitor electrodes due to its environment-friendly characteristic and easy processing. However, most of the chitosan-based porous carbon preparation method was complicated and required some activators such as zinc chloride and potassium hydroxide (KOH), which were all not conducive to environmental and equipment protection. Herein, we have successfully used a one-step carbonization method to prepare N-doped hierarchical porous carbon by systematically combining a small amount of KOH with magnesium acetate. The phenomenon was confirmed by observing scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), and nitrogen adsorption/desorption isotherms. The porous carbon showed a high specific surface area of ~2737 m2 g−1, and its nitrogen content was up to 2.39%. Electrochemical data exhibited that the chitosan-based carbon electrode could achieve an outstanding gravimetric capacitance of 300.5 F g−1 at a current density of 0.5 A g−1. After cyclic charging and discharging 5000 times at a current density of 5 A g−1, the specific capacitance retention rate was 92.94%. As an assembled symmetrical supercapacitor, with 6 M KOH as the electrolyte, when the power density was 250–4991 W kg−1, the corresponding energy density was 7.3–6.1 Wh kg−1. Thus, these chitosan-based porous carbon electrodes exhibited excellent electrochemical properties. Particularly, the strategy to prepare porous carbon would provide successful experiences for designing bio-polymers porous carbon.