In this work, we report on the gas-sensing behavior of Al-doped SnO2 nanotubes (NTs) in order to evaluate the effect of Al on improved sensing performance and propose an oxygen-vacancy-dominating ...sensing mechanism of SnO2. The hierarchical mesoporous Al-doped SnO2 NTs are fabricated by simple electrospinning method and annealing treatment. Al-doping shows profound influence on the oxygen vacancy of SnO2 which changes as a function of Al/(Al+Sn) ratio and the oxygen vacancy exhibits a maximum value when the ratio is 8%. As a result, the gas-sensing response to formaldehyde varies following the oxygen vacancies. Oxygen vacancies at the surface of SnO2 facilitate oxygen adsorption and the formation of surface catalytic active O−O−, thus the gas response is remarkably enhanced. Furthermore, a new fundamental understanding toward the gas-sensing performance of oxygen-vacancy-dominating SnO2 is proposed.
Establishing an advanced ecosystem incorporating freshwater harvesting, plastic utilization, and clean fuel acquisition is profoundly significant. However, low‐efficiency evaporation, single energy ...utilization, and catalyst leakage severely hinder sustainable development. Herein, a nanofiber‐based mortise‐and‐tenon structural Janus aerogel (MTSJA) is strategically designed in the first attempt and supports Z‐scheme catalysts. By harnessing of the upper hydrophilic layer with hydrophilic channels embedding into the hydrophobic bottom layer to achieve tailoring bottom wettability states. MTSJA is capable of a fully‐floating function for lower heat loss, water supply, and high‐efficiency solar‐to‐vapor conversion. Benefiting from the ultrasonic cavitation effect and high sensitivity of materials to mechanical forces, this is also the first demonstration of synergistic solar and ultrasound fields to power simultaneous evaporation desalination and waste plastics as reusable substrates generating fuel energy. The system enables persistent desalination with an exceptional evaporation rate of 3.1 kg m−2 h−1 and 82.3% efficiency (21 wt.% NaCl solution and 1 sun), and realizes H2, CO, and CH4 yields with 16.1, 9.5, and 3 µmol h−1 g−1, respectively. This strategy holds great potential for desalination and plastics value‐added transformation toward clean energy and carbon neutrality.
This is the first demonstration of strategically designed fully floating mortise‐and‐tenon structure Janus aerogels to support Z‐type heterojunction, and also for the first time, utilizing the incorporation of synergetic photo and ultrasound fields can achieve evaporation desalination and catalytic plastic as feedstocks for the value‐added transformation of H2O and CO2.
A mononuclear methyl maltolate (Hmm) coordinated oxidovanadium(V) complex VOL1(mm) (1), and a mononuclear ethyl maltolate (Hem) coordinated oxidovanadium(V) complex VOL2(em) (2), where L1 and L2 are ...the dianionic form of N'-(2-hydroxy-5-methylbenzylidene)-3-trifluoromethylbenzohydrazide (H2L1) and N'-(2-hydroxy-5-methylbenzylidene)-4-trifluoromethylbenzohydrazide (H2L2), respectively, have been prepared. The hydrazones and the complexes were characterized by elemental analysis, FT-IR and UV-Vis spectra. Structures of H2L1 and the two complexes were further characterized by single crystal X-ray diffraction. The two complexes have similar structures, with the V atoms in octahedral coordination. The hydrazones behave as ONO tridentate ligands with the V atoms. Both complexes have interesting properties on the catalytic epoxidation of cyclooctene.
Display omitted
•A bifunctional silica gel-immobilized ditopic Schiff base ligand was prepared.•The adsorbent can simultaneously adsorb Cu(II) and SO42− ions from CuSO4 solution.•The adsorbent can ...selectively adsorb Cu(II) and SO42− from mixed metal salts solution.•The adsorbent exhibits good regeneration and reusability.•The mechanisms for simultaneous and selective adsorptions were discussed.
A ditopic zwitterionic Schiff base modified silica gel adsorbent SG-H2L2 was prepared and it was characterized by Fourier transform infrared spectroscopy, elemental analysis, solid state NMR, thermogravimetry and porous structure analysis. SG-H2L2 could simultaneously adsorb metal ions and attendant anions from the aqueous solution of metal salts. SG-H2L2 exhibited a cooperative effect between the adsorption of metal cations and the attendant anions, and the adsorption efficiency decreased in the order MSO4>M(NO3)2>MCl2 (M=Cu, Co, Ni, Mn, Cd). SG-H2L2 displayed good adsorption selectivity for Cu(II) and SO42− from the aqueous solutions containing mixed metal ions of Cu(II), Co(II), Ni(II), Mn(II) and Cd(II) or mixed anions of SO42−, NO3−, and Cl−. The preliminary mechanism for simultaneous and selective adsorption of the metal ions and attendant anions were discussed. The effect of different parameters including pH, contact time and initial concentrations of Cu(II) and SO42− on the simultaneous adsorption of Cu(II) and SO42− ions were investigated. The efficient adsorption of Cu(II) and SO42− could be achieved in neutral pH region and the maximum adsorption capacities for Cu(II) and SO42−, respectively, were the same of 0.42mmolg−1 at 25°C. The adsorption isotherms for Cu(II) and SO42− fitted well with Langmuir model, while their adsorption kinetics followed the pseudo-second order model. Regeneration of SG-H2L2 was realized by adjusting the solution pH with diluted H2SO4 and ammonia solution, respectively. SG-H2L2 exhibited good recyclability and reusability for four cycles use without deterioration in its functionality. SG-H2L2 was also applied in different water samples and good recoveries and the selective adsorption of Cu(II) and SO42− were achieved. This study provides a new bifunctional adsorbent which may be used for the effective removal of Cu(II) and SO42− from water effluents containing mixed metal ions and anions.
Display omitted
► Co
2+–HCO
3
−–H
2O
2 system efficiently catalyzes degradation of highly stable organic dyes. ► The rate of
OH radicals production increases after Co
2+–methylene blue complexes ...formation. ► The tested other pollutants play an important role in
OH radicals production in the system.
The kinetics and mechanism of a simple system, Co
2+–HCO
3
−–H
2O
2 for degrading highly stable organic pollutants have been reported. Fast and versatile decolorization of organic dyes was observed in an aqueous solution containing 10
mM NaHCO
3, 10
μM Co
2+ ions and 10
mM H
2O
2, while the degradation rate of p-nitrophenol and 2,4-dinitrophenol was very slow. From cyclic voltammetry and UV–vis spectra, it was found that different complexes between Co
2+ ions and methylene blue (MB) were formed in HCO
3
− solution, and being confirmed by photoluminescence probing and electron spin resonance spin-trapping technologies, the 1:1 complex Co
II(HCO
3
−)(MB)
+ was more efficient in catalyzing decomposition of H
2O
2 into
OH radicals. The other tested pollutants also played an important role in the rate of
OH radicals production in the system. Based on the kinetic observations of MB decolorization, a possible mechanism was proposed.
Establishing an advanced ecosystem incorporating freshwater harvesting, plastic utilization, and clean fuel acquisition is profoundly significant. However, low-efficiency evaporation, single energy ...utilization, and catalyst leakage severely hinder sustainable development. Herein, a nanofiber-based mortise-and-tenon structural Janus aerogel (MTSJA) is strategically designed in the first attempt and supports Z-scheme catalysts. By harnessing of the upper hydrophilic layer with hydrophilic channels embedding into the hydrophobic bottom layer to achieve tailoring bottom wettability states. MTSJA is capable of a fully-floating function for lower heat loss, water supply, and high-efficiency solar-to-vapor conversion. Benefiting from the ultrasonic cavitation effect and high sensitivity of materials to mechanical forces, this is also the first demonstration of synergistic solar and ultrasound fields to power simultaneous evaporation desalination and waste plastics as reusable substrates generating fuel energy. The system enables persistent desalination with an exceptional evaporation rate of 3.1 kg m
h
and 82.3% efficiency (21 wt.% NaCl solution and 1 sun), and realizes H
, CO, and CH
yields with 16.1, 9.5, and 3 µmol h
g
, respectively. This strategy holds great potential for desalination and plastics value-added transformation toward clean energy and carbon neutrality.
In order to investigate the impact of perspiration on photo-induced chemical reaction of azo dyes and the carcinogenic aromatic amine products produced from the reaction, we have carried out ...experimental studies on the photochemical reaction of C.I. Reactive Red 2 mixed with American Association of Textile Chemists and Colorists（AATCC）standard artificial perspiration. UV–vis spectroscopic technique was employed to monitor the reaction processes, and the reaction products were analyzed by hollow fiber protected liquid-liquid-liquid phase micro-extraction with capillary electrophoresis（HF-LLLME-CE). The results showed that perspiration had remarkable influence on the photochemical reaction of azo dyes. Aromtic amines formed during the photochemical process as a result of reduction of azo dyes by organic components in perspiration. The HF-LLLME-CE methodology was validated in analyzing aromatic amines produced from the photochemical degradation of azo dye C.I. Reactive Red 2 and C.I. Acid Red 35 mixed with artificial perspiration.
► The synergistic effect of perspiration on photo-induced degradation of azo dyes was investigated. Organic components of perspiration and light intensity show remarkable affect. Inorganic salts in perspiration have inhibiting function. Employment of HF-LLLPME-CE realized the determination of aromatic amines in perspiration. Aniline and O-toluidine generated from azo dyes under photo-perspiration system were determined.
The amino-functionalized magnetic nanoadsorbent Fe3O4@SiO2-NH2 was prepared and it was characterized by X-ray powder diffraction, transmission electron microscopy, Fourier transform infrared (FT-IR) ...spectroscopy, and thermogravimetric analysis (TGA). The adsorption of anionic dyes including Acid Orange II (AO II) and Reactive Brilliant Red X-3B (X-3B) onto Fe3O4@SiO2-NH2 was investigated. The results showed that Fe3O4@SiO2-NH2 exhibited efficient adsorption for these anionic dyes under acidic conditions, and it was proposed to proceed via electrostatic attraction and hydrogen bonding between the positively charged protonated amino groups (–NH3+) on the adsorbent surface and the negatively charged sulfonate groups (–SO3-) of the dyes. The mechanism was supported by density functional theory (DFT) calculations. The adsorption kinetics for AO II and X-3B on Fe3O4@SiO2-NH2 followed the pseudo-second-order kinetic model, and the adsorption equilibrium data fitted well with Langmuir isotherm model. The maximum adsorption capacities for AO II and X-3B at pH 2 under room temperature were 132.2 and 233.1 mg g−1, respectively. Desorption of dyes and regeneration of the adsorbent were carried out using aqueous solution at pH 10. The adsorbent Fe3O4@SiO2-NH2 could be easily recovered by external magnet and it exhibited good recyclability and reusability for three cycles use.
