In this work the development of RMs of mass concetration of the main components (propanol-1 and propanol-2) in biological objects (urine, blood) are described.
During the past two years, the introduction of DMSO has revolutionized the fabrication of high-quality pervoskite MAPbI3 (MA = CH3NH3) films for solar cell applications. In the developed DMSO ...process, the formation of (MA)2Pb3I8·2DMSO (shorted as Pb3I8) has well recognized as a critical factor to prepare high-quality pervoskite films and thus accomplish excellent performances in perovskite solar cells. However, Pb3I8 is an I-deficient intermediate and must further react with methylammonium iodide (MAI) to be fully converted into MAPbI3. By capturing and solving the molecular structures of several intermediates involved in the fabrication of perovskite films, we report in this work that the importance of DMSO is NOT due to the formation of Pb3I8. The use of different PbI2-DMSO ratios leads to two different structures of PbI2-DMSO precursors (PbI2·DMSO and PbI2·2DMSO), thus dramatically influencing the quality of fabricated perovskite films. However, such an influence can be minimized when the PbI2-DMSO precursor films are thermally treated to create mesoporous PbI2 films before reacting with MAI. Such a development makes the fabrication of high-quality pervoskite films highly reproducible without the need to precisely control the PbI2:DMSO ratio. Moreover, the formation of ionic compound (MA)4PbI6 is observed when excess MAI is used in the preparation of perovskite film. This I-rich phase heavily induces the hysteresis in PSCs, but is readily removed by isopropanol treatment. On the basis of all these findings, we develop a new effective protocol to fabricate high-performance PSCs. In the new protocol, high-quality perovskite films are prepared by simply treating the mesoporous PbI2 films (made from PbI2-DMSO precursors) with an isopropanol solution of MAI, followed by isopropanol washing. The best efficiency of fabricated MAPbI3 PSCs is up to 19.0%. As compared to the previously reported DMSO method, the devices fabricated by the method reported in this work display narrow efficiency distributions in both forward and reverse scans. And the efficiency difference between forward and reverse scans is much smaller.
•IBE-gasoline blends with various IBE content were tested.•Combustion, performance and emissions characteristics were investigated.•IBE-gasoline blends showed an advanced combustion phasing compared ...to G100.•IBE30 performed well in BTE and emissions among IBE-gasoline blends.•IBE30 showed higher BTE and lower emissions compared to G100.
Among primary alcohols, bio-n-butanol is considered as a promising alternative fuel candidate. However, relatively low production efficiency and high cost of component recovery from the acetone-n-butanol-ethanol (ABE) or isopropanol-n-butanol-ethanol (IBE) fermentation processes hinders industrial-scale production of bio-n-butanol. Hence it is of interest to study the intermediate fermentation product, i.e. ABE and IBE as a potential alternative fuels. However, for fuel applications, the IBE mixture appears to be more attractive than ABE due to more favorable properties of isopropanol over acetone, such as being less corrosive to engine part, higher energy density and octane number. In this study, an experimental investigation on the performance, combustion and emission characteristics of a port fuel-injection SI engine fueled with IBE-gasoline blends was carried out. By comparisons between IBE-gasoline blends with various IBE content (0–60vol.% referred to as G100-IBE60) and more commonly used alternative alcohol fuels (ethanol, n-butanol and ABE)-gasoline blends, it was found that IBE30 performed well with respect to engine performance and emissions, including brake thermal efficiency (BTE), brake specific fuel consumption (BSFC), carbon monoxide (CO), unburned hydrocarbons (UHC) and nitrogen oxides (NOx). Then, IBE30 was selected to be compared with G100 under various equivalence ratio (Φ=0.83–1) and engine load (300 and 500kPa BMEP). Overall, higher BTE (0.04–4.3%) and lower CO (4%), UHC (15.1–20.3%) and NOx (3.3–18.6%) emissions were produced by IBE30 compared to G100. Therefore, IBE could be a good alternative fuel to gasoline due to the environmentally benign fermentation process (from non-edible biomass feedstock and without recovery process) and the potential to improve energy efficiency and reduce pollutant emissions.
Biochar, produced through pyrolysis of organic matter, is negatively charged, thus contributing to electrostatic adsorption of cations. However, due to its porous structure and contents of alkaline ...ashes, the determination of the cation exchange capacity (CEC) is challenging. Literature values for the CEC of biochar are surprisingly variable and are often poorly reproducible, suggesting methodological problems. Here, we modify and critically assess different steps in the existing ammonium acetate (NH4OAc) method (pH 7), where ammonium (NH4+) is displaced by potassium chloride (KCl), following removal of excess NH4OAc with isopropanol, in batch mode. We used pigeon pea biochar to develop the method and conducted a test on three additional biochars with different acid neutralizing capacity. A pretreatment step of biochar was introduced, using diluted hydrochloric acid, to decrease biochar pH to near neutral, so that 1 M NH4OAc effectively buffers the biochar suspension pH at 7. This allows the CEC of all biochars to be determined at pH 7, which is crucial for biochar comparison. The dissolution of ashes may cause relatively large weight losses (e.g. for cacao shell biochar), which need to be accounted for when computing the CEC of raw biochar. The sum of NH4OAC-extractable base cations provided a smaller and better estimate of the CEC than KCl-extractable NH4+. We hypothesize that the overestimation of the CEC based on KCl-extractable NH4+ is due to the ineffectiveness of the relatively large isopropanol molecules to remove excess NH4OAc in biochars rich in micro-pores, due to size exclusion. The amount of base cations removed in the pretreatment was about three (rice husk biochar) to ten times (pigeon pea biochar) greater than the amount of exchangeable cations. The CEC values of biochar increased from 10.8 cmol/Kg carbon to 119.6 cmol/Kg carbon. These values are smaller than reported CEC values of soil organic carbon.
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•The ammonium acetate (NH4OAc) method was validated in batch for different biochars.•CEC estimates were based on sum of base cations and displaced NH4+ by K+.•Optimal equilibration time and amount of NH4OAc and KCl were established.•The role of readily soluble and exchangeable cations was compared.•Isopropanol did not penetrate all the micro-pores of some biochars.
Researchers are showing significant interest in the development of nanostructures with hierarchical porosity. This study introduces an eco-friendly, cost-effective, and straightforward method to ...create SnO2 hollow porous nanostructures using the peony as a biotemplate. A comprehensive analysis of the gas sensing characteristics of these hierarchical SnO2 hollow porous nanostructures is conducted. The results show that the gas sensor based on SnO2 showcases relatively high response values measuring 18.3 and exhibits rapid response speed of 1 s to 100 ppm isopropanol, even at a comparably low operating temperature of 180 °C. Additionally, the sensor displays good repeatability and long-term stability, which can be attributed to the inherent advantages stemming from its distinct structure. Therefore, this study provides experimental and theoretical foundations for the potential application of hollow porous SnO2 structures in sensor technology.
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•Novel tricarbohydrazide BTCH is synthesized and characterized.•Network cross-linking of PI membranes by BTCH for pervaporation dehydration.•Higher BTCH content results in higher ...cross-linking degree and hydrophilicity.•Membrane-forming temperature affects membrane properties and performance.
Amine cross-linking is one of the popular modifications of polyimide membranes in order to improve their operation stability and separation performance. In this work, a novel kind of cross-linker tricarbohydrazide — 1,3,5-benzenetricarboxylic acid trihydrazide (BTCH), is synthesized and incorporated into polyimide membranes for isopropanol dehydration via pervaporation. The chemical structure of BTCH is examined by NMR and FTIR to confirm the successful synthesis. The effects of BTCH content and membrane-forming temperature on the membrane physicochemical properties and separation performance are studied and characterized by various techniques. And the possible reaction mechanism during the chemical cross-linking is proposed and analyzed. This work is believed to shed useful insights on the chemical modification of polyimide membranes for pervaporation and other membrane-based separation applications.
Two-dimensional (2D) perovskite of (C(NH2)3)(CH3NH3)nPbnI3n+1 (shorten as (GA)MAnPbnI3n+1) is with alternating cations (GA+ and MA+) in the interlayer space (ACI). n = 1 of (GA)MAPbI4 film can ...transform from red to black in appearance after soaking in isopropanol (IPA) for 5 s, resulting in the peaks of PL from 570 nm to 770 nm. Using X-ray diffraction and Fourier-transform infrared spectroscopy, we find that the IPA can dissolve GA+ cation from the film effectively, thus n = 1 layered structure is destroyed, leaving larger n phases of (GA)MAnPbnI3n+1 in film. By controlling the reaction time with IPA solvent, the n = 1 film can rearrange into new material of mixture with various n values, which present tunable absorption and photoluminescence spectra. Our work may not only explore the novel phenomena of ACI 2D perovskite, but also provide a simple method to synthesize quasi 2D perovskite with adjustable n values.
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•Isopropanol (IPA) can solve GA+ effectively from (GA)MAPbI4 film.•Large n phases of (GA)MAnPbnI3n+1) was left after IPA treatment.•Modifying the reaction time of (GA)MAPbI4 film can achieve tunable n materials.•The novel phenomena of ACI 2D perovskite.
Efficient generation of active oxygen-related radicals plays an essential role in boosting advanced oxidation process. To promote photocatalytic oxidation for gaseous pollutant over g-C3N4, a ...solid–gas interfacial Fenton reaction is coupled into alkalinized g-C3N4-based photocatalyst to effectively convert photocatalytic generation of H2O2 into oxygen-related radicals. This system includes light energy as power, alkalinized g-C3N4-based photocatalyst as an in situ and robust H2O2 generator, and surface-decorated Fe3+ as a trigger of H2O2 conversion, which attains highly efficient and universal activity for photodegradation of volatile organic compounds (VOCs). Taking the photooxidation of isopropanol as model reaction, this system achieves a photoactivity of 2–3 orders of magnitude higher than that of pristine g-C3N4, which corresponds to a high apparent quantum yield of 49% at around 420 nm. In-situ electron spin resonance (ESR) spectroscopy and sacrificial-reagent incorporated photocatalytic characterizations indicate that the notable photoactivity promotion could be ascribed to the collaboration between photocarriers (electrons and holes) and Fenton process to produce abundant and reactive oxygen-related radicals. The strategy of coupling solid–gas interfacial Fenton process into semiconductor-based photocatalysis provides a facile and promising solution to the remediation of air pollution via solar energy.
This study aims to investigate the impact of isopropanol on the optical properties of the Fe₃O₄/ZnO/GQDs nanocomposite. The synthesis of Fe₃O₄ and ZnO nanoparticles was conducted using the ...coprecipitation method, followed by the synthesis of GQDs using the hydrothermal method with varying concentrations of isopropanol. Subsequently, the Fe₃O₄/ZnO nanocomposite was combined with GQDs synthesized using the sonication method. The amalgamation of magnetic and luminescent materials holds promise for applications in the biomedical field, particularly in bioimaging. XRD data analysis revealed crystal structure alterations attributed to the incorporation of carbon elements in both ZnO and Fe₃O₄. The TEM results indicated a particle size of 16.2 nm for the Fe₃O₄/ZnO/GQDs nanocomposite with a 10 ml isopropanol variation. Identified phases from the XRD analysis include Fe₃O₄, ZnO, and GQDs. UV-Vis spectroscopy detected distinctive absorbance peaks at wavelengths of 323.7 nm, 333.0 nm, 329.9 nm, and 323.9 nm. Moreover, the energy gap exhibited an increase with escalating concentrations of isopropanol in the GQDs. Photoluminescence analysis yielded robust, broad emission bands characterized by orange and red luminescence.
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