A solid-state pulse power sub-nanosecond SiC DSRD-based generator with high-voltage and high repetition frequency for pulse discharge water treatment.

Water treatment is one of the most important issues for all walks of life around the world. The unique advantages of the solid-state power electronic pulses in water treatment make it attractive and promising in practical applications. The output voltage, rising time, repetition rate, and peak power of output pulses have a significant impact on the effectiveness of water treatment. Especially in pulse electric field treatment and pulse discharge treatment, the pulse with fast rising time achieves the advantage of generating plasma without corona, which can avoid water heating effect and greatly improve the efficiency of the pulse generator. High repetition rate can significantly reduce the peak power requirement of the pulse in water treatment application, making the equipment smaller and improving the power density. Therefore, the study developed a high-voltage high frequency sub-nanosecond pulse power generator (PPG) system for wastewater treatment. It adopts SiC DSRD (Drift Step Recovery Diode) solid-state switches and realize modular design, which can achieve high performance and can be flexible expanded according to the requirements of water treatment capacity. Finally, an expandable high-voltage PPG for water treatment is built. The output parameters of the PPG include output pulse voltage range from 1 to 5.28 kV, rise time <600 ps (20%-90%), repetition up to 1 MHz. The experiment results of PPG application for pulse discharge water treatment is presented. The results indicate that the proposed generator achieves high-efficiency degradation of 4-Chlorophenol (4-CP), which is one of the most common chlorophenol compounds in wastewater. From experiment, the homemade system can degrade 450 mL waste water containing 500 mg/L 4-CP in 35 min, with a degradation rate of 98%. Thereby, the requirement for electric field intensity decreased. Through the further quantitative analysis, the impact of frequency, voltage, and electrode spacing on the degradation effect of 4-CP is confirmed.

A Lotus Seedpods-Inspired Interfacial Solar Steam Generator with Outstanding Salt Tolerance and Mechanical Properties for Efficient and Stable Seawater Desalination.

Interfacial solar steam generators (ISSGs) can capture solar energy and concentrate the heat at the gas-liquid interface, resulting in efficient water evaporation. However, traditional ISSGs have limitations in long-term seawater desalination processes, such as limited light absorption area, slow water transport speed, severe surface salt accumulation, and weak mechanical performance. Inspired by lotus seedpods, a novel ISSG (rGO-SA-PSF) is developed by treating a 3D warp-knitted spacer fabric with plasma (PSF) and combining it with sodium alginate (SA) and reduces graphene oxide (rGO). The rGO-SA-PSF utilizes a core-suction effect to achieve rapid water pumping and employs aerogel to encapsulate the plasma-treated spacer yarns to create the lotus seedpod-inspired hydrophilic stems, innovatively constructing multiple directional water transport channels. Simultaneously, the large holes of rGO-SA-PSF on the upper layer form lotus seedpod-inspired head concave holes, enabling efficient light capture. Under 1 kW m-2 illumination, rGO-SA-PSF exhibits a rapid evaporation rate of 1.85 kg m-2  h-1 , with an efficiency of 96.4%. Additionally, it shows superior salt tolerance (with no salt accumulation during continuous evaporation for 10 h in 10% brine) and self-desalination performance during long-term seawater desalination processes. This biomimetic ISSG offers a promising solution for efficient and stable seawater desalination and wastewater purification.

An efficient interfacial solar evaporator featuring a hierarchical porous structure entirely derived from waste cotton.

Interfacial solar evaporators are widely used to purify water. However, photothermal materials commonly constituting most interfacial solar evaporators remain expensive; additionally, the inherent structure of the evaporators limits their performance. Furthermore, the large amount of waste cotton produced by the textile industry is an environmental threat. To address these issues, we propose an interfacial solar evaporator, H-CA-CS, with a hierarchical porous structure. This evaporator is made entirely of waste cotton and uses carbon microspheres (CMS) and cellulose aerogel (CA) as photothermal and substrate materials, respectively. Additionally, its photothermal layer (CS layer) has large pores and a high porosity, which promote light absorption and timely vapor escape. In contrast, the water transport layer (CA layer) has small pores, providing a robust capillary effect for water transport. Combined with the outstanding light absorption properties of CMS, H-CA-CS exhibited superior overall performance. We found that H-CA-CS has an excellent evaporation rate (1.68 kg m-2 h-1) and an efficiency of 90.6 % under one solar illumination (1 kW m-2), which are superior to those of many waste-based solar evaporators. Moreover, H-CA-CS maintained a mean evaporation rate of 1.61 kg m-2 h-1, ensuring sustainable evaporation performance under long-term scenarios. Additionally, H-CA-CS can be used to purify seawater and various types of wastewater with removal efficiencies exceeding 99 %. In conclusion, this study proposes a method for efficiently using waste cotton to purify water and provides novel ideas for the high-value use of other waste fibers to further mitigate ongoing environmental degradation.

The Effects of Oil and Gas Produced Water on Soil Bacterial Community Structure in the Arid Desert Area.

The safe utilization and risk assessment of produced water (PW) from oil and gas fields for desert irrigation have received increasing attention in recent years. In this context, this study aimed to analyze structural changes in soil bacterial community, and assess the environmental impact of PW discharge and irrigation over time. High-throughput sequencing technology was employed to examine the structure of the soil bacterial community in the constructed wetland and its surrounding desert vegetation irrigation region where PW was released for a considerable amount of time (30 years). The results revealed that long-term discharge of PW and irrigation significantly reduced the abundance of the soil bacterial community but did not significantly alter the richness and diversity of the soil bacterial community. Proteobacteria was the dominant bacterial phyla in soil, but in irrigated and drained areas, the dominant bacterial phyla changed from Alphaproteobacteria to Gammaproteobacteria, the Firmicutes abundance was significantly reduced.

miR-545 promotes colorectal cancer by inhibiting transferring in the non-normal ferroptosis signaling.

In this study, we examined whether and how miR-545 modulates ferroptosis in colorectal cancer (CRC). HT-29 and HCT-116 human CRC cell viability was examined using a CCK-8 assay and malondialdehyde (MDA) and Fe2+ levels were measured after treatment with the ferroptosis inducers Eradicator of Ras and ST (erastin) and Ras selective lethal 3 (RSL3) with or without miR-545 overexpression or knockdown vectors. Our results demonstrate that miR-545 overexpression inhibited, while miR-545 knockdown further increased, erastin and RSL3-induced upregulation of MDA, reactive oxygen species (ROS), and Fe2+ levels. Similarly, miR-545 overexpression partially reversed, while miR-545 knockdown enhanced, the erastin and RSL3-induced reduction in HT-29 and HCT-116 cell survival rates. Transferrin (TF) was identified as a target gene of miR-545. To determine whether miR-545 suppresses ferroptosis via TF, we overexpressed TF in HT-29 and HCT-116 cells. We found that TF overexpression blocked miR-545-induced changes in ROS, MDA, and Fe2+ levels in HT-29 and HCT-116 cells, thereby inducing CRC cell death. An in vivo assay showed that inhibition of miR-545 decreased tumor growth in nude mice treated with erastin. Together, these findings indicate that miR-545 promotes CRC cell survival by suppressing TF.

Chemical Adsorption Strategy for DMC-MeOH Mixture Separation.

The effective separation of dimethyl carbonate (DMC) from its methanol mixture through simple, inexpensive and low energy-input method is a promising and challenging field in the process of organic synthesis. Herein, a reversible adsorption strategy through the assistance of superbase and CO2 for DMC/methanol separation at ambient condition was described. The process was demonstrated effectively via the excellent CO2 adsorption efficiency. Notably, the protocol was also suitable to other alcohol (i.e., monohydric alcohol, dihydric alcohol, trihydric alcohol) mixtures. The study provided guidance for potential separation of DMC/alcohol mixture in the scale-up production.

Effects of 5 MeV Proton Irradiation on Nitrided SiO2/4H-SiC MOS Capacitors and the Related Mechanisms.

In this paper the effects of 5 MeV proton irradiation on nitrided SiO2/4H-SiC metal-oxide-semiconductor (MOS) capacitors are studied in detail and the related mechanisms are revealed. The density of interface states (Dit) is increased with the irradiation doses, and the annealing response suggests that the worse of Dit is mainly caused by displacement effect of proton irradiation. However, the X-rays photoelectron spectroscopy (XPS) measurement shows that the quantity proportion of breaking of Si≡N induced by displacement is only 8%, which means that the numbers of near interface electron traps (NIETs) and near interface hole traps (NIHTs) are not significantly changed by the displacement effect. The measurements of bidirectional high frequency (HF) C-V characteristics and positive bias stress stability show that the number of un-trapped NIETs and oxide electron traps decreased with increasing irradiation doses because they are filled by electrons resulted from the ionization effect of proton irradiation, benefiting to the field effective mobility (µFE) and threshold voltage stability of metal-oxide-semiconductor field-effect transistors (MOSFETs). The obviously negative shift of flat-band voltage (VFB) resulted from the dominant NIHTs induced by nitrogen passivation capture more holes produced by ionization effect, which has been revealed by the experimental samples with different nitrogen content under same irradiation dose.

Enhanced Photocatalytic Properties of PET Filaments Coated with Ag-N Co-Doped TiO2 Nanoparticles Sensitized with Disperse Blue Dyes.

In this study, the effects of disperse blue dye-sensitization on the photocatalytic properties of the Ag-N co-doped TiO2 nanoparticles loaded on polyethylene terephthalate (PET) filaments are investigated under visible light irradiation. The microstructure and photocatalytic properties of the as-synthesized TiO2 nanocomposites, as well as the as-prepared PET filaments, are systematically characterized. The photocatalytic performance of the PET filaments coated with the Ag-N co-doped TiO2 nanoparticles sensitized with disperse blue dyes is evaluated via its capacity of photo-degrading methyl orange (MO) dyes under visible light irradiation. It is found that the holes are the predominant reactive radical species and the hydroxyl and superoxide radicals play a subordinate role in the photocatalytic reaction process. The reaction rate constant of the photocatalytic composite filaments is nearly 4.0 times higher than that of the PET filaments loaded solely with TiO2 nanoparticles. The resultant photocatalytic composite filaments are evident to be capable of repeatedly photo-degrading MO dyes without losing its photocatalytic activity significantly.

The Oral NOAEL of Flurochloridone in Male Wistar Rats in Ninety-Day Subchronic Toxicity Test Was 3mg/kg/day.

A ninety-day toxicity and toxicokinetics of flurochloridone (FLC) were studied in male Wistar rats with oral administration at doses of 3 mg/kg and 10 mg/kg respectively, following the previous study. Apparent toxicity to reproductive system of male rats was still observed at the dose of 10 mg/kg, trace amounts of FLC were still detected 24 hours after administration, testicular weight, epididymal weight and serum testosterone were significantly reduced and sperm abnormalities in epididymis were significantly increased. No abnormalities were found in 3 mg/kg group, it indicated that no-observed-adverse-effect level (NOAEL) of FLC in male rats was 3 mg/kg/day, far below the dose of 20 mg/kg/day reported by European Food Safety Authority (EFSA). Therefore, more attention should be paid to this herbicide.

Atomic zinc dispersed on graphene synthesized for active CO2 fixation to cyclic carbonates.

CO2 fixation to cyclic carbonates is important but depends on the catalyst. Here, atomic zinc (1.62 at%) dispersed on graphene was synthesized as a high-performance heterocatalyst for the cycloaddition reaction of epoxides and CO2. High yield (99%) and high selectivity (98%) of propylene carbonate with a TOF of 2889 h-1 were achieved. [ZnN3.76±0.2] was the active site, which was proved by advanced characterization, including synchrotron XANES, EXAFS and XPS and comparative performance tests.

Catalytic Conversion of Carbon Dioxide through C-N Bond Formation.

From the viewpoint of green chemistry and sustainable development, it is of great significance to synthesize chemicals from CO2 as C1 source through C-N bond formation. During the past several decade years, many studies on C-N bond formation reaction were involved, and many efforts have been made on the theory. Nevertheless, several great challenges such as thermodynamic limitation, low catalytic efficiency and selectivity, and high pressure etc. are still suffered. Herein, recent advances are highlighted on the development of catalytic methods for chemical fixation of CO2 to various chemicals through C-N bond formation. Meanwhile, the catalytic systems (metal and metal-free catalysis), strategies and catalytic mechanism are summarized and discussed in detail. Besides, this review also covers some novel synthetic strategies to urethanes based on amines and CO2. Finally, the regulatory strategies on functionalization of CO2 for N-methylation/N-formylation of amines with phenylsilane and heterogeneous catalysis N-methylation of amines with CO2 and H2 are emphasized.

AgI /TMG-Promoted Cascade Reaction of Propargyl Alcohols, Carbon Dioxide, and 2-Aminoethanols to 2-Oxazolidinones.

Chemical valorization of CO2 to access various value-added compounds has been a long-term and challenging objective from the viewpoint of sustainable chemistry. Herein, a one-pot three-component reaction of terminal propargyl alcohols, CO2 , and 2-aminoethanols was developed for the synthesis of 2-oxazolidinones and an equal amount of α-hydroxyl ketones promoted by Ag2 O/TMG (1,1,3,3-tetramethylguanidine) with a TON (turnover number) of up to 1260. By addition of terminal propargyl alcohol, the thermodynamic disadvantage of the conventional 2-aminoethanol/CO2 coupling was ameliorated. Mechanistic investigations including control experiments, DFT calculation, kinetic and NMR studies suggest that the reaction proceeds through a cascade pathway and TMG could activate propargyl alcohol and 2-aminoethanol through the formation of hydrogen bonds and also activate CO2 .

Silver(I)-Promoted Cascade Reaction of Propargylic Alcohols, Carbon Dioxide, and Vicinal Diols: Thermodynamically Favorable Route to Cyclic Carbonates.

A silver(I)-promoted cascade reaction was developed for the synthesis of cyclic carbonates from terminal propargylic alcohols, carbon dioxide, and vicinal diols. Compared with direct condensation of vicinal diols with CO2, this protocol provides a thermodynamically favorable route to cyclic carbonates and α-hydroxyl ketones in excellent yields (up to 97%) without the additional dehydration step. Such a cascade procedure proceeds presumably through initial reaction of propargylic alcohol with CO2 and subsequent nucleophilic attack of vicinal alcohol on in situ-formed α-alkylidene cyclic carbonate, resulting in successive generation of α-alkylidene cyclic carbonate, unsymmetrical ß-oxoalkyl carbonate, cyclic carbonate, and α-hydroxyl ketone.

Thermodynamically Favorable Synthesis of 2-Oxazolidinones through Silver-Catalyzed Reaction of Propargylic Alcohols, CO2, and 2-Aminoethanols.

Development of catalytic routes to incorporate CO2 into carbonyl compounds at mild conditions remains attractive and challenging. Herein, a one-pot three-component cascade reaction of terminal propargylic alcohols, CO2 , and 2-aminoethanols through Ag(I) -based catalysis is reported for the synthesis of carbonyl compounds through C-O/C-N bond formation. This thermodynamically favorable route can be ingeniously regulated to afford a wide range of 2-oxazolidinones along with concurrent production of α-hydroxyl ketone derivatives in excellent yields and selectivity. Preliminary mechanistic studies indicate that such a process proceeds through successive formation of α-alkylidene cyclic carbonate, ß-oxopropylcarbamate, and 2-oxazolidinones.

Silver(I)-Catalyzed Three-Component Reaction of Propargylic Alcohols, Carbon Dioxide and Monohydric Alcohols: Thermodynamically Feasible Access to ß-Oxopropyl Carbonates.

A silver(I)-catalyzed three-component reaction of propargylic alcohols, CO2 , and monohydric alcohols was successfully developed for the synthesis of ß-oxopropyl carbonates. As such, a series of ß-oxopropyl carbonates were exclusively produced in excellent yields (up to 98 %), even under atmospheric pressure of CO2 . The silver catalyst works efficiently for both the carboxylative cyclization of propargylic alcohols with CO2 and subsequent transesterification of α-alkylidene cyclic carbonates with monohydric alcohols; thus this tandem process performs smoothly under mild conditions. This work provides a versatile and thermodynamically favorable approach to dissymmetric dialkyl carbonates.

Cu(II)-catalyzed esterification reaction via aerobic oxidative cleavage of C(CO)-C(alkyl) bonds.

A novel Cu(II)-catalyzed aerobic oxidative esterification of simple ketones for the synthesis of esters has been developed with wide functional group tolerance. This process is assumed to go through a tandem sequence consisting of α-oxygenation/esterification/nucleophilic addition/C-C bond cleavage and carbon dioxide is released as the only byproduct.

Silver(I)-Catalyzed Synthesis of ß-Oxopropylcarbamates from Propargylic Alcohols and CO2 Surrogate: A Gas-Free Process.

The utilization of carbon dioxide poses major challenges owing to its high thermodynamic stability and kinetic inertness. To circumvent these problems, a simple reaction system is reported comprising ammonium carbamates as carbon dioxide surrogates, propargylic alcohols, and a silver(I) catalyst, for the effective conversion of a wide range of alcohols and secondary amines into the corresponding ß-oxopropylcarbamates. A key feature of this strategy includes quantitative use of a carbon resource with high product yields under gas-free and mild reaction conditions. Notably, this catalytic protocol also works well for the carboxylative cyclization of propargylic amines and carbon dioxide surrogates to afford 2-oxazolidinones.

Bifunctional silver(I) complex-catalyzed CO2 conversion at ambient conditions: synthesis of α-methylene cyclic carbonates and derivatives.

The chemical conversion of CO2 at atmospheric pressure and room temperature remains a great challenge. The triphenylphosphine complex of silver(I) carbonate was proved to be a robust bifunctional catalyst for the carboxylative cyclization of propargylic alcohols and CO2 at ambient conditions leading to the formation of α-methylene cyclic carbonates in excellent yields. The unprecedented performance of [(PPh3)2Ag]2CO3 is presumably attributed to the simultaneous activation of CO2 and propargylic alcohol. Moreover, the highly compatible basicity of the catalytic species allows propargylic alcohol to react with CO2 leading to key silver alkylcarbonate intermediates: the bulkier [(Ph3P)2Ag(I)](+) effectively activates the carbon-carbon triple bond and enhances O-nucleophilicity of the alkylcarbonic anion, thereby greatly promoting the intramolecular nucleophilic cyclization. Notably, this catalytic protocol also worked well for the reaction of propargylic alcohols, secondary amines, and CO2 (at atmospheric pressure) to afford ß-oxopropylcarbamates.

Equimolar carbon absorption by potassium phthalimide and in situ catalytic conversion under mild conditions.

Potassium phthalimide, with weak basicity, is an excellent absorbent for rapid carbon dioxide capture with almost equimolar absorption. This process is assumed to proceed through the potassium carbamate formation pathway, as supported by NMR spectroscopy, an in situ FTIR study, and computational calculations. Both the basicity and nucleophilicity of phthalimide salts have a crucial effect on the capture process. Furthermore, the captured carbon dioxide could more easily be converted in situ into value-added chemicals and fuel-related products through carbon capture and utilization, rather than going through a desorption process.

Equimolar CO2 capture by N-substituted amino acid salts and subsequent conversion.

Steric bulk controls CO(2) absorption: N-substituted amino acid salts in poly(ethylene glycol) reversibly absorb CO(2) in nearly 1:1 stoichiometry. Carbamic acid is thought to be the absorbed form of CO(2); this was supported by NMR and in situ IR spectroscopy, and DFT calculations. The captured CO(2) could be converted directly into oxazolidinones and thus CO(2) desorption could be sidestepped.