This study proposed an electrochemical technique for investigating the mechanism of nonradical oxidation of organics with peroxydisulfate (PDS) activated by carbon nanotubes (CNT). The ...electrochemical property of twelve phenolic compounds (PCs) was evaluated by their half-wave potentials, which were then correlated to their kinetic rate constants in the PDS/CNT system. Integrated with quantitative structure–activity relationships (QSARs), electron paramagnetic resonance (EPR), and radical scavenging tests, the nature of nonradical pathways of phenolic compound oxidation was unveiled to be an electron-transfer regime other than a singlet oxygenation process. The QSARs were established according to their standard electrode potentials, activation energy, and pre-exponential factor. A facile electrochemical analysis method (chronopotentiometry combined with chronoamperometry) was also employed to probe the mechanism, suggesting that PDS was catalyzed initially by CNT to form a CNT surface-confined and -activated PDS (CNT–PDS*) complex with a high redox potential. Then, the CNT–PDS* complex selectively abstracted electrons from the co-adsorbed PCs to initiate the oxidation. Finally, a comparison of PDS/CNT and graphite anodic oxidation under constant potentials was comprehensively analyzed to unveil the relative activity of the nonradical CNT–PDS* complex toward the oxidation of different PCs, which was found to be dependent on the oxidative potentials of the CNT–PDS* complex and the adsorbed organics.
Solar steam generation (SSG) is widely regarded as one of the most sustainable technologies for seawater desalination. However, salt fouling severely compromises the evaporation performance and ...lifetime of evaporators, limiting their practical applications. Herein, we propose a hierarchical salt-rejection (HSR) strategy to prevent salt precipitation during long-term evaporation while maintaining a rapid evaporation rate, even in high-salinity brine. The salt diffusion process is segmented into three steps—insulation, branching diffusion, and arterial transport—that significantly enhance the salt-resistance properties of the evaporator. Moreover, the HSR strategy overcomes the tradeoff between salt resistance and evaporation rate. Consequently, a high evaporation rate of 2.84 kg m−2 h−1, stable evaporation for 7 days cyclic tests in 20 wt% NaCl solution, and continuous operation for 170 h in natural seawater under 1 sun illumination were achieved. Compared with control evaporators, the HSR evaporator exhibited a >54% enhancement in total water evaporation mass during 24 h continuous evaporation in 20 wt% salt water. Furthermore, a water collection device equipped with the HSR evaporator realized a high water purification rate (1.1 kg m−2 h−1), highlighting its potential for agricultural applications.
Background:
Patients with antineutrophil cytoplasmic antibody-associated vasculitis (AAV) may require intensive care unit (ICU) admission due to different reasons, and the in-ICU mortality is high ...among AAV patients. The aim of this study was to explore the clinical features and risk factors of mortality of patients with AAV in the ICU.
Methods:
A retrospective study was conducted based on 83 AAV patients admitted to the ICU in a tertiary medical institution in China. Data on clinical characteristics, laboratory tests, treatment in ICU and outcomes were collected. The data were analyzed using univariate and multivariate logistic regression analysis to explore the variables that were independently related to mortality. Kaplan–Meier method was used to assess the long-term survival.
Results:
Among the 83 patients, 41 (49.4%) were female. The mean age of patients was 66 ± 13 years. Forty-four patients deceased, with the in-ICU mortality of 53%. The most common cause for ICU admission was active vasculitis (40/83, 48.2%). The main cause of death was infection (27/44, 61.4%) followed by active vasculitis (15/44, 34.1%). A multivariate analysis revealed that the Acute Physiology and Chronic Health Evaluation II (APACHE II) at ICU admission (
OR
= 1.333, 95%
CI
: 1.031–1.722) and respiratory failure (
OR
= 620.452, 95%
CI
: 11.495–33490.306) were independent risk factors of in-ICU death. However, hemoglobin (
OR
= 0.919, 95%
CI
: 0.849–0.995) was an independent protective factor. The nomogram established in this study was practical in predicting the risk of in-ICU mortality for AAV patients. Moreover, for 39 patients survived to the ICU stay, the cumulative survival rates at 0.5, 1, and 5 years were 58.3%, 54.2%, and 33.9%, respectively, and the median survival time was 14 months.
Conclusion:
In our study, active vasculitis was the most frequent reason for ICU admission, and the main cause of death was infection. APACHE II and respiratory failure were independent risk factors while hemoglobin was an independent protective factor of in-ICU mortality for AAV patients admitted to the ICU. The risk prediction model developed in this study may be a useful tool for clinicians in early recognition of high-risk patients and applying appropriate management.
A novel MOF-based S-scheme heterostructure of MIL101-(Fe)/Bi2WO6 was designed and synthesized for efficient photocatalytic elimination of Cr(VI) and antbiotic tetracycline hydrochloride by virtue of ...the abundant reactive sites and OV-mediated S-scheme photo-carrier separation mechanism.
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•A dual dual-functional photosystem of defective MIL-101(Fe)/Bi2WO6 S-scheme heterojunction was designed.•MIL-101(Fe)/Bi2WO6 showed excellent activity for removal of Cr(VI) and tetracycline under visible light.•The high specific surface area and OV-mediated S-scheme structure contribute to the excellent photocatalytic performance.•The degradation process of tetracycline and eco-toxicity of the intermediates were investigated.
Solar-driven elimination of refractory contaminants is an ideal route to tackle the environmental issues. Nevertheless, the photocatalytic performance of photocatalysts is heavily restrained due to the insufficient accessible reactive sites and fast electrons/holes reunion. Herein, a novel metal–organic framework-based S-scheme heterostructure of MIL-101(Fe)/Bi2WO6 was synthesized by a simple solvothermal approach. The optimized MIL-101(Fe)/Bi2WO6 (MIL/BWO-2) affords the highest photo-activities under visible light, which are 13.7, 6.7 folds greater for Cr(VI) reduction, and 0.8, 10.5 folds higher for tetracycline hydrochloride oxidation compared with individual Bi2WO6 and MIL-101(Fe), respectively. The preeminent catalytic capability lies in two aspects: 1) the introduction of MIL-101(Fe) substantially enlarges the surface area of the composites, offering ample reaction sites and fostering pollutant adsorption and mass transportation; 2) the novel S-scheme photo-carrier transport mechanism assisted by oxygen vacancies favors spatial segregation and transport of photoinduced electrons/holes with superior redox capacity. Reactive species identification experiments verify that O2– and e– dominantly contribute to Cr(VI) reduction, while O2–, h+ and OH account for tetracycline hydrochloride destruction. Furthermore, the tetracycline photo-decomposition pathway, eco-toxicity evaluation, and photocatalytic mechanism were investigated comprehensively. This research paves the way for building high-performance MOFs-based S-scheme heterojunctions toward photocatalytic water purification.
As a special class of coordinated frameworks comprised of various metal species, Prussian blue analogues (PBAs) have received increasing attention for catalytic applications. Nevertheless, few ...studies have been performed to investigate catalytic activities of PBAs for hydrogen generation (HG) from NaBH
4
hydrolysis. No researches have been implemented to examine effects of different M
II
and M
III
of PBAs (M
II
3
M
III
(CN)
6
2
) (M
II
= Co, Fe, Mn, Ni, and Zn; M
III
= Fe, Co) on NaBH
4
hydrolysis for HG. Thus, the aim of the study is to explore and compare catalytic activities of various PBAs for HG from NaBH
4
hydrolysis. While two hexacyano-metalates and different metals are used to obtain various PBAs, Co
3
Co(CN
6
)
2
(Co–Co) is the most effective PBA for HG from NaBH
4
hydrolysis. Furthermore, Co–Co has a much lower
E
a
of 37.6 kJ/mol for HG from NaBH
4
hydrolysis in comparison to
E
a
values by other reported catalysts. Besides, HG by Co–Co could be optimized in the presence of 5% NaOH concentration, which leads to an even lower
E
a
of 28.6 kJ/mol. Co–Co is also reusable and stable for multiple cycles of HG. These features reveal that Co-containing PBAs can be a promising heterogeneous catalyst to facilitate HG from NaBH
4
hydrolysis.
•Studies of MOFs- and MOPs-based photocatalysts for CO2 conversion in gas–solid-phase are overviewed.•Research progress of photocatalytic conversion in different CO2 atmospheres are ...highlighted.•Perspectives and challenges of photoreduction CO2 under aerobic conditions are presented.
Photocatalytic carbon dioxide (CO2) reduction is a promising strategy to mitigate global warming and supply green fuels and chemicals. However, due to the low CO2 adsorption capacity of the photocatalysts and limited CO2 dissolution, the conversion rate of CO2 and selectivity in the aqueous solution is typically unsatisfactory, which cannot meet the requirements of practical application. This paper reviewed the latest advances in metal–organic frameworks (MOFs)- and polymer-based photocatalysts for the gas–solid conversion of CO2. Various atmospheres are reviewed, including high-purity CO2, diluted CO2, and CO2/O2 mixtures. Due to favorable adsorption and selectivity toward CO2, porous photocatalysts show high efficiency in photocatalysis, even at ultralow CO2 concentration or in the presence of oxygen. In addition, we summarize the challenges in photo-CO2- reduction technology under the gas–solid phase and provide perspectives on the development of multifunctional materials with high CO2 adsorption and photocatalytic conversion performances.
Bis(4-hydroxyphenyl)methanone (BHPM), a common ultraviolet stabilizer and filter (USF), is extensively added in sunscreens; however, BHPM is proven as an endocrine disruptor, posing a serious threat ...to aquatic ecology, and BHPM should be then removed. As sulfate radical (SO4•−) could be useful for eliminating emerging contaminants, oxone appears as a favorable source reagent of SO4•− for degrading BHPM. Even though cobalt is a useful catalyst for activating oxone to generate SO4•−, it would be even more promising to utilize ambient-visible-light irradiation to enhance oxone activation using cobaltic catalysts. Therefore, in contrast to the conventional cobalt oxide, cobalt titanium oxide (CTO) was investigated for chemical and photocatalytic activation of oxone to eliminate BHPM from water. Especially, a special morphology of nanosheet-assembled configuration of CTO was designed to maximize active surfaces and sites of CTO. Thus, CTO outperforms Co3O4 and TiO2 in degrading BHPM via oxone activation. Furthermore, the substituent of Ti enabled CTO to enhance absorption of visible light and possessed a much smaller Eg. These photocatalytic properties intensified CTO’s activity for oxone activation. CTO possessed a significantly smaller Ea of degradation of USFs than other catalytic systems. Mechanistic insight for degrading BHPM by CTO + oxone was explicated for identifying contribution of reactive oxygen species to BHPM degradation. The BHPM degradation pathway was also investigated and unveiled in details via the DFT calculation. These results validated that CTO is a superior cobaltic alternative for activating oxone to eliminate BHPM.
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•3D cubic mesoporous carbons were employed for persulfate (PS) activation.•The carbocatalysts exhibited adsorptive removal and catalytic oxidation of phenolics.•The carbon materials ...are more effective than the homogeneous metal-based system.•CMK-3/PS is comparable to the most efficient Fe0/PS for catalytic phenol oxidation.•Both radical and nonradical pathways contributed to the organic degradation.
Carbon materials have been demonstrated as effective and metal-free carbocatalysts for substituting the toxic and/or expensive transition and noble metals/oxides for various green chemical processes. In this study, three-dimensional cubic mesoporous carbon (CMK) materials were employed for adsorptive and oxidative removal (via heterogeneous persulfate activation) of toxic phenolic compounds. CMK-3 and CMK-8 are constructed with porous structures and larger specific areas of 1129 and 1072m2/g, respectively. They achieved 39.2% and 31.3% of phenol adsorption in aqueous solutions. CMK-3 and CMK-8 also demonstrated as superb persulfate (PS) activators, providing 100% phenol oxidation in 20 and 45min accordingly with high rate constants of 0.209 and 0.104min−1, respectively. The metal-free systems are more efficient than Fe2+ or Ag+ based homogeneous systems. Moreover, CMK-3/PS can be comparable to the classical zero-valent iron (ZVI)/PS system without inducing any metal ions to the waterbody. The mechanistic study indicated that persulfate activation on CMKs was different from the Fe2+/PS, Ag+/PS, and ZVI/PS systems. A nonradical pathway was unveiled in the metal-free persulfate activation for catalytic oxidation in which persulfate was activated on the carbon lattice and oxidized the adsorbed phenol molecules via a rapid electron transfer. The edging sites and kenotic groups of carbon materials would mediate persulfate to produce sulfate radicals. Both the radical pathway and nonradical process contributed to the complete phenol removal, and the great adsorption capability of CMKs further promoted the adsorption of the organic and oxidant for enhanced catalytic processes. The study dedicates to a metal-free oxidative system with cheap carbon materials for wastewater treatment and environmental remediation.
Catalytic membranes can simultaneously realize physical separation and chemical oxidation in one integrated system, which is the frontier technology for effective removal of organic containments in ...wastewater treatment. The catalytic membrane coupled with advanced oxidation processes (AOPs) not only significantly enhances the pollutant removal efficiency but also inhibits the fouling of the membrane via self-cleaning. In this review, the preparation approaches of catalytic membranes including blending, surface coating, and bottom-up synthesis are comprehensively summarized. The different integrated catalytic membrane systems coupled with photocatalysis, Fenton oxidation, persulfate activations, ozonation and electrocatalytic oxidation are discussed in terms of mechanisms and performance. Besides, the principles, influencing factors, advantages and issues of the different catalytic membrane/oxidation systems are outlined comparatively. Finally, the future challenges, and research directions are suggested, which is conducive to the design and development of catalytic membrane-oxidation systems for practical remediation of organic containing wastewater.
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•The preparation approaches of catalytic membranes are summarized.•The catalytic membranes coupled with advanced oxidation systems are classified.•The principles and advantages of catalytic membrane/oxidation systems are outlined.•The future challenges of catalytic membrane-based water treatment are proposed.
The possible release of selectable marker genes from genetically modified transgenic plants, or of gut microbes, to the environment, has raised worldwide public concerns. In this study, we showed the ...generation of marker-free transgenic maize plants constitutively expressing AtNHX1, a Na+/H+ antiporter gene from Arabidopsis that conferred salt tolerance on plants, using the FLP/FRT site-specific recombination system. Transgenic plant expressing a modified FLP recombinase gene was crossed with transgenic plant harboring AtNHX1 and mutant als, a selectable marker gene flanked by two directed FRT sites. The sexual crossing led to precise and complete excision of the FRT-surrounded als marker gene in the F1 progenies. Further salt tolerance examinations indicated that marker-free AtNHX1 transgenic plants accumulated more Na+ and K+, and produced greater biomass and yields than did the wild-type plants when grown in high saline fields. These results demonstrate the feasibility of using this FLP/FRT-based marker elimination system to generate marker-free transgenic important cereal crops with improved salt tolerance.
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