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1.
Toxicology ; : 153849, 2024 May 29.
Article in English | MEDLINE | ID: mdl-38821197

ABSTRACT

The individual toxicity of sodium fluoride (NaF) and microplastics (MPs) has been extensively documented. Owing to their high specific surface area, widespread presence and durability, MPs can adsorb a broad spectrum of environmental contaminants into the organism. However, the combined toxicity of NaF and MPs has not been investigated. This study aimed to assess the effects of combined exposure to NaF and MPs on the function of testicular Sertoli cells (SCs) in male mice, and to investigate the underlying molecular mechanisms. The study revealed that combined exposure to NaF and MPs resulted in a decrease in the negative surface charge of MPs, along with an increase in the number of MPs entering the SCs. Through in vivo observation of the testicular pathological structure, spermatogenesis, and cell apoptosis in 180-day-old male mice, we discovered that combined exposure to NaF (80mg/L) and MPs (10mg/L) heightened reproductive toxicity compared to the individual exposure groups. This was evidenced by testicular structural defects, impaired spermatogenesis, and increased testicular cell apoptosis. Our in vitro studies showed that NaF (21µg/mL) and MPs (100µg/mL) synergistically induced SCs apoptosis and ferroptosis, leading to a reduction in SCs number and dysfunction. This ultimately resulted in structural and functional damage to the testes. Our findings demonstrate, for the first time, the synergistic effects of NaF and MPs on reproductive toxicity in mammals. These insights may provide valuable contributions to co-toxicity studies involving MPs and other environmental pollutants.

2.
Se Pu ; 42(4): 360-367, 2024 Apr.
Article in Chinese | MEDLINE | ID: mdl-38566425

ABSTRACT

The macroporous anion exchange chromatographic medium (FastSep-PAA) was prepared through grafting polyallylamine (PAA) onto polyacrylate macroporous microspheres (FastSep-epoxy). The effects of the synthesis conditions, including the PAA concentration, reaction time, and reaction solution pH, on the ion exchange (IC) of the medium were investigated in detail. When the PAA concentration, reaction time, and reaction solution pH were increased, the IC of the medium increased, and optimal synthesis conditions were then selected in combination with changes of protein binding capacity. A scanning electron microscope was used to examine the surface morphology of the medium. The medium possessed high pore connectivity. Furthermore, the pore structure of the medium was preserved after the grafting of PAA onto the macroporous microspheres. This finding demonstrates that the density of the PAA ligands does not appear to have any discernible impact on the structure of the medium; that is, no difference in the structure of the medium is observed before and after the grafting of PAA onto the microspheres. The pore size and pore-size distribution of the medium before and after grafting were determined by mercury intrusion porosimetry and the nitrogen adsorption method to investigate the relationship between pore size (measured in the range of 300-1000 nm) and protein adsorption. When the pore size of the medium was increased, its protein binding capacity did not exhibit any substantial decrease. An increase in pore size may hasten the mass transfer of proteins within the medium. Among the media prepared, that with a pore size of 400 nm exhibited the highest dynamic-binding capacity (DBC: 70.3 g/L at 126 cm/h). The large specific surface area of the medium and its increased number of protein adsorption sites appeared to positively influence its DBC. When the flow rate was increased, the protein DBC decreased in media with original pore sizes of less than 700 nm. In the case of the medium with an original pore size of 1000 nm, the protein DBC was independent of the flow rate. The protein DBC decreased by 3.5% when the flow rate was increased from 126 to 628 cm/h. In addition, the protein DBC was maintained at 57.7 g/L even when the flow velocity was 628 cm/h. This finding reveals that the diffusion rate of protein molecules at this pore size is less restricted and that the prepared medium has excellent mass-transfer performance. These results confirm that the macroporous polymer anion exchange chromatographic medium developed in this study has great potential for the high-throughput separation of proteins.


Subject(s)
Polyamines , Proteins , Chromatography, Ion Exchange/methods , Adsorption , Proteins/chemistry , Anions
3.
PLoS One ; 19(4): e0301580, 2024.
Article in English | MEDLINE | ID: mdl-38625876

ABSTRACT

Unpaired image-to-image translation (I2IT) involves establishing an effective mapping between the source and target domains to enable cross-domain image transformation. Previous contrastive learning methods inadequately accounted for the variations in features between two domains and the interrelatedness of elements within the features. Consequently, this can result in challenges encompassing model instability and the blurring of image edge features. To this end, we propose a multi-attention bidirectional contrastive learning method for unpaired I2IT, referred to as MabCUT. We design separate embedding blocks for each domain based on depthwise separable convolutions and train them simultaneously from both the source and target domains. Then we utilize a pixel-level multi-attention extractor to query images from embedding blocks in order to select feature blocks with crucial information, thus preserving essential features from the source domain. To enhance the feature representation capability of the model, we incorporate depthwise separable convolutions for the generator. We conducted comprehensive evaluations using three datasets, demonstrating that our approach enhances the quality of unpaired I2IT while avoiding the issue of mode collapse-related image blurring.

4.
Ecotoxicol Environ Saf ; 273: 116079, 2024 Mar 15.
Article in English | MEDLINE | ID: mdl-38377778

ABSTRACT

Nicotine, an addictive component of cigarettes, causes cognitive defects, particularly when exposure occurs early in life. However, the exact mechanism through which nicotine causes toxicity and alters synaptic plasticity is still not fully understood. The aim of the current study is to examine how non-coding developmental regulatory RNA impacts the hippocampus of mice offspring whose mothers were exposed to nicotine. Female C57BL/6J mice were given nicotine water from one week before pregnancy until end of lactation. Hippocampal tissue from offspring at 20 days post-birth was used for LncRNA and mRNA microarray analysis. Differential expression of LncRNAs and mRNAs associated with neuronal development were screened and validated, and the CeRNA pathway mediating neuronal synaptic plasticity GM13530/miR-7119-3p/mef2c was predicted using LncBase Predicted v.2. Using protein immunoblotting, Golgi staining and behavioral tests, our findings revealed that nicotine exposure in offspring mice increased hippocampal NMDAR receptor, activated receptor-dependent calcium channels, enhanced the formation of NMDAR/nNOS/PSD95 ternary complexes, increased NO synthesis, mediated p38 activation, induced neuronal excitability toxicity. Furthermore, an epigenetic CeRNA regulatory mechanism was identified, which suppresses Mef2c-mediated synaptic plasticity and leads to modifications in the learning and social behavior of the offspring during adolescence. This study uncovers the way in which maternal nicotine exposure results in neurotoxicity in offspring.


Subject(s)
Nicotine , Prenatal Exposure Delayed Effects , Pregnancy , Humans , Mice , Animals , Female , Nicotine/toxicity , Nicotine/metabolism , RNA, Competitive Endogenous , Prenatal Exposure Delayed Effects/genetics , Prenatal Exposure Delayed Effects/metabolism , Mice, Inbred C57BL , Maternal Exposure/adverse effects , Hippocampus/metabolism
5.
Ecotoxicol Environ Saf ; 271: 115972, 2024 Feb.
Article in English | MEDLINE | ID: mdl-38218105

ABSTRACT

Coal worker's pneumoconiosis (CWP) is a common occupational disease that coal miners are highly susceptible due to long-term exposure to coal dust particles (CDP). CWP can induce the accumulation of immune cells surrounding the bronchioles and alveoli in the lungs, resulting in pulmonary fibrosis and compromised immune function. Using single-cell RNA sequencing (scRNA-Seq), our previous studies disclose that CDP exposure triggers heterogeneity of transcriptional profiles in mouse pneumoconiosis, while Vitamin D3 (VitD3) supplementation reduces CDP-induced cytotoxicity; however, the mechanism by which how VitD3 regulates immune status in coal pneumoconiosis remains unclear. In this study, we elucidated the heterogeneity of pulmonary lymphocytes in mice exposed to CDP and demonstrated the therapeutic efficacy of VitD3 using scRNA-Seq dataset. The validation of key lymphocyte markers and their functional molecules was performed using immunofluorescence. The results demonstrated that VitD3 increased the number of naive T cells by modulating CD4 + T cell differentiation and decreased the number of Treg cells in CDP-exposed mice, thereby enhancing the cytotoxic activity of CD8 + effector T cells. These effects markedly alleviated lung fibrosis and symptoms. Taken together, the mechanism by which VitD3 regulates the functions of lymphocytes in CWP provides a new perspective for further research on the prevention and treatment of CWP.


Subject(s)
Anthracosis , Coal Mining , Pneumoconiosis , Pulmonary Fibrosis , Animals , Mice , Pneumoconiosis/diagnosis , Pulmonary Fibrosis/chemically induced , Coal , Immune Tolerance
6.
RSC Adv ; 14(4): 2850-2861, 2024 Jan 10.
Article in English | MEDLINE | ID: mdl-38234868

ABSTRACT

A series of Ru-Sn/γ-Al2O3 catalysts were prepared by the immersion method for tetramethylcyclobutane-1,3-dione (TMCB) hydrogenation to prepare 2,2,4,4-tetramethyl-1,3-cyclobutanediol (CBDO). The effect of the preparation method and reaction technology on TMCB hydrogenation activity was discussed. The catalysts were analyzed by means of XRD, BET, H2-TPR, XPS, scanning electron microscopy (SEM), and transmission electron microscopy (TEM), and it was found that the synthesized Ru was distributed on the surface of the carrier in the form of nanoparticles, showing a good catalytic effect. The results showed that when Ru loading was fixed at 5%, Sn was used as an auxiliary agent, and Ru/Sn = 1 : 1 as the catalyst, the reaction conditions were 120 °C, 4 MPa, and 1 h, and the catalytic hydrogenation effect of TMCB on CBDO was the best. The selectivity was as high as 73.5%, and the cis-trans ratio was 1.11. It may be the strong interaction between Ru and Sn under this ratio condition, which leads to the largest number of nano-active centers of elemental Ru. Finally, the reaction mechanism of TMCB hydrogenation to CBDO is discussed.

7.
Adv Mater ; 36(14): e2309298, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38146682

ABSTRACT

Solid-state sodium (Na) batteries (SSNBs) hold great promise but suffer from several major issues, such as high interfacial resistance at the solid electrolyte/electrode interface and Na metal dendrite growth. To address these issues, a piezoelectric interlayer design for an Na3Zr2Si2PO12 (NZSP) solid electrolyte is proposed herein. Two typical piezoelectric films, AlN and ZnO, coated onto NZSP function as interlayers designed to generate a local stress-induced field for alleviating interfacial charge aggregation coupling stress concentration and promoting uniform Na plating. The results reveal that the interlayer (ZnO) with matched modulus, high Na-adhesion, and sufficient piezoelectricity can provide a favorable interphase. Low interfacial resistances of 91 and 239 Ω cm2 are achieved for the ZnO layer at 30 and 0 °C, respectively, which are notably lower than those for bare NZSP. Moreover, steady Na plating/stripping cycles are rendered over 850 and 4900 h at 0 and 30 °C, respectively. The superior anodic performance is further manifested in an Na2MnFe(CN)6-based full cell which delivers discharge capacities of 125 mA h g-1 over 1600 cycles at 30 °C and 90 mA h g-1 over 500 cycles at 0 °C. A new interlayer-design insight is clearly demonstrated for SSNBs breaking low-temperature limits.

8.
ACS Appl Mater Interfaces ; 16(1): 860-868, 2024 Jan 10.
Article in English | MEDLINE | ID: mdl-38151338

ABSTRACT

Due to the strong Coulomb interaction, in most polymer photocatalysts, electron-hole pairs exist in the form of excitons rather than free charge carriers. The giant excitonic effect is a key obstacle to generating free charge carriers. Therefore, effectively regulating the exciton effect is the first step to achieving optimized carrier separation. Here, we used C-ring/g-C3N4 as the prototypical model system to design a photocatalyst with a Na-coordination-induced trap state. We demonstrate that the excitons can be effectively dissociated into charge carriers by combining with the trap state formed by Na doping sites. Encouragingly, signals from the dissociation of excitons into carriers were observed by ultrafast transient spectroscopy. Benefiting from the enhanced exciton dissociation, Na-C/CN displayed a H2O2 production rate of 17.4 mmol·L-1·h-1 with an apparent quantum efficiency up to 26.9% at 380 nm, which is much higher than many other g-C3N4-based photocatalysts. This work explains the effect of cation doping on the exciton-carrier behavior in polymers. Also, it provides a new way to regulate the exciton effect.

9.
Spectrochim Acta A Mol Biomol Spectrosc ; 308: 123785, 2024 Mar 05.
Article in English | MEDLINE | ID: mdl-38134652

ABSTRACT

A novel dual-emission fluorescent nanoprobe based on rare-earth nanosheets was fabricated to detect 2,6-pyridine dicarboxylic acid (DPA), which is the biomarker of Bacillus anthracis. 2-amino terephthalic acid (BDC-NH2) and surfactant sodium dodecyl sulfate (SDS) were co-intercalated into layered europium hydroxide (LEuH) to prepare the organic/inorganic composite, which was delaminated to obtain the rare-earth nanosheets. The ratio detection of DPA is possible due to the antenna effect between DPA and Eu3+. The nanoprobe shows high accuracy and sensitivity due to the large specific surface area of the rare-earth nanosheets. The limit of detection (LOD) is 4.4 nM for DPA in the range of 0-20 µM. In addition, a more convenient and faster smartphone-based visual detection platform was established based on the obvious color change. This work offers an effective way for developing visual sensing platforms, which opens a new path for designing fluorescent probes with superior sensing capabilities.


Subject(s)
Anthrax , Bacillus anthracis , Humans , Anthrax/diagnosis , Smartphone , Europium , Fluorescent Dyes , Biomarkers
10.
Opt Express ; 31(24): 40270-40284, 2023 Nov 20.
Article in English | MEDLINE | ID: mdl-38041332

ABSTRACT

In this work, a novel Global NV-ETM RCWA method is proposed to accelerate the optimization of the periodic stepped radar absorbing structure. This method is based on the rigorous coupled-wave analysis (RCWA) utilizing the normal vector field (NV) and enhanced transmittance matrix (ETM) approach. The NV field dramatically improves the convergence rate for both dielectric and magnetic metasurfaces. The Global NV-ETM RCWA algorithm is developed to further accelerate the complete search calculations. Using the proposed method, the periodic stepped radar absorbing structures are efficiently optimized to realize the entire band absorption in 2-18 GHz. The optimization results demonstrate the Global NV-ETM RCWA method significantly increase the computational efficiency, with a 38-fold improvement over direct NV-ETM RCWA calculations when the truncation order N=3. This method provides a powerful tool for designing metasurface absorbers with various desired functionalities.

11.
Food Chem Toxicol ; 181: 114104, 2023 Nov.
Article in English | MEDLINE | ID: mdl-37848122

ABSTRACT

Microplastics (MPs) are plastic pollutants with a diameter of less than 5 mm and microcystins (MCs) are natural toxins produced by cyanobacteria. In recent years, the pollution of MPs and MCs attracted widespread attention. However, our understanding about the toxic effects of co-exposure of MPs and MCs on male reproduction is limited. Mice were continuously exposed to 0.04mg/(kg*bw) microcystin-leucine-arginine (MC-LR) or 45 mg/(kg*bw) polystyrene microplastics (PS-MPs) or a mixed solution of 0.04mg/(kg*bw) MC-LR and 45 mg/(kg*bw) PS-MPs by gavage for 28 days in this study. The results showed that PS-MPs could absorb MC-LR in ddH2O and MC-LR content in testis was increased in the group with combined exposure when compared to the group only exposed to MC-LR. Exposure to PS-MPs or MC-LR individually could destroy testis structure, increase the level of tissue apoptosis and decrease the quality of sperm, while the co-exposure enhanced the toxic effects. Furthermore, PS-MPs could carry MC-LR into testis Leydig cells, reduce testosterone levels and mRNA expression levels of key molecules involved in testosterone synthesis (StAR, P450scc, P450c17,3ß-HSD and 17ß-HSD). Among them, the combined effect of PS-MPs-MC-LR was the most severe. In summary, this study provides new insights into the toxicity of MPs and MCs in mammals.


Subject(s)
Microcystins , Microplastics , Mice , Male , Animals , Microcystins/toxicity , Plastics , Polystyrenes/toxicity , Semen , Reproduction , Testosterone , Mammals
12.
ACS Appl Mater Interfaces ; 15(42): 49321-49328, 2023 Oct 25.
Article in English | MEDLINE | ID: mdl-37847183

ABSTRACT

Solid-state metal batteries with nonflammable solid-state electrolytes are regarded as the next generation of energy storage technology on account of their high safety and energy density. However, as for most solid electrolytes, low room temperature ionic conductivity and interfacial issues hinder their practical application. In this work, Na super ionic conductor (NASICON)-type Na3Zr2Si2PO12 (NZSP) electrolytes with improved ionic conductivity are synthesized by the NaBr-assisted sintering method. The effects of the NaBr sintering aid on the crystalline phase, microstructure, densification degree, and electrical performance as well as the electrochemical performances of the NZSP ceramic electrolyte are investigated in detail. Specifically, the NZSP-7%NaBr-1150 ceramic electrolyte has an ionic conductivity of 1.2 × 10-3 S cm-1 (at 25 °C) together with an activation energy of 0.28 eV. A low interfacial resistance of 35 Ω cm2 is achieved with the Na/NZSP-7%NaBr-1150 interface. Furthermore, the Na/NZSP-7%NaBr-1150/Na3V2(PO4)3 battery manifests excellent cycling stability with a capacity retention of 98% after 400 cycles at 1 C and 25 °C.

13.
Adv Sci (Weinh) ; 10(27): e2302774, 2023 Sep.
Article in English | MEDLINE | ID: mdl-37485585

ABSTRACT

Achieving satisfactory performance for a solid-state Na-metal battery (SSNMB) with an inorganic solid electrolyte (SE), especially under freezing temperatures, poses a challenge for stabilizing a Na-metal anode. Herein, this challenge is addressed by utilizing a Natrium super ionic conductor (NASICON) NASICON-type solid electrolyte, enabling the operation of a rechargeable SSNMB over a wide temperature range from -20 to 45 °C. The interfacial resistance at the Na metal/SE interface is only 0.4 Ω cm2 at 45 °C and remains below 110 Ω cm2 even at -20 °C. Remarkably, long-term Na-metal plating/stripping cycles lasting over 2000 h at -20 °C are achieved with minimal polarization voltages at 0.1 mA cm-2 . Further analysis reveals the formation of a uniform Na3- x Cax PO4 interphase layer at the interface, which significantly contributes to the exceptional interfacial performance observed. By employing a Na3 V1.5 Al0.5 (PO4 )3 cathode, the full battery system demonstrates excellent adaptability to low temperatures, exhibiting a capacity of 80 mA h g-1 at -20 °C over 50 cycles and retaining a capacity of 108 mAh g-1 (88.5% of the capacity at 45 °C) at 0 °C over 275 cycles. This research significantly reduces the temperature threshold for SSNMB operation and paves the way toward solid-state batteries suitable for all-season applications.

14.
Nanomicro Lett ; 15(1): 143, 2023 Jun 02.
Article in English | MEDLINE | ID: mdl-37266746

ABSTRACT

The performance of proton exchange membrane fuel cells is heavily dependent on the microstructure of electrode catalyst especially at low catalyst loadings. This work shows a hybrid electrocatalyst consisting of PtNi-W alloy nanocrystals loaded on carbon surface with atomically dispersed W sites by a two-step straightforward method. Single-atomic W can be found on the carbon surface, which can form protonic acid sites and establish an extended proton transport network at the catalyst surface. When implemented in membrane electrode assembly as cathode at ultra-low loading of 0.05 mgPt cm-2, the peak power density of the cell is enhanced by 64.4% compared to that with the commercial Pt/C catalyst. The theoretical calculation suggests that the single-atomic W possesses a favorable energetics toward the formation of *OOH whereby the intermediates can be efficiently converted and further reduced to water, revealing a interfacial cascade catalysis facilitated by the single-atomic W. This work highlights a novel functional hybrid electrocatalyst design from the atomic level that enables to solve the bottle-neck issues at device level.

15.
Spectrochim Acta A Mol Biomol Spectrosc ; 299: 122793, 2023 Oct 15.
Article in English | MEDLINE | ID: mdl-37187145

ABSTRACT

A novel core-shell structure ratiometric fluorescent probe was developed, which can selectively and sensitively detect 2,6-dipicolinic acid (DPA) as an anthrax biomarker. Carbon dots (CDs) was embedded into SiO2 nanoparticles, which was acted as an internal reference signal. Tb3+ with green emission was connected to the carboxyl functionalized SiO2, which was acted as a responsive signal. With the addition of DPA, the emission of CDs at 340 nm was unchanged, while the fluorescence of Tb3+ at 544 nm was enhanced by the antenna effect. In the concentration range of 0.1-2 µM, the fluorescence intensity ratio of I544/I340 showed a good linear relationship with the concentration of DPA, and the limit of detection (LOD) was 10.2 nM. In addition, the dual-emission probe showed an obvious fluorescence color change from colourless to green with increasing DPA under UV light, which enabled visual detection.


Subject(s)
Anthrax , Quantum Dots , Humans , Anthrax/diagnosis , Fluorescent Dyes/chemistry , Carbon/chemistry , Silicon Dioxide/chemistry , Biomarkers , Quantum Dots/chemistry
16.
Small ; 19(33): e2301230, 2023 Aug.
Article in English | MEDLINE | ID: mdl-37081280

ABSTRACT

In this work, an efficient screening method to select appropriate sintering aids for a wide range of oxide material systems is developed. Consequently, Na2 B4 O7 , NaF, and CuO are selected as sintering aids for sodium super ionic conductor (NASICON)-type Na3 Zr2 Si2 PO12 ceramic to verify the feasibility of the as-proposed method. As evidenced by the results, the sinterability and densification of ceramic matrix are apparently improved. Specifically, Na3 Zr2 Si2 PO12 -7%Na2 B4 O7 , Na3 Zr2 Si2 PO12 -3%NaF, and Na3 Zr2 Si2 PO12 -3%CuO endow much higher room temperature ionic conductivity of 1.03 × 10-3 , 1.61 × 10-3 , and 1.63 × 10-3  S cm-1 , respectively, in comparison with the pristine (7.23 × 10-4  S cm-1 ). The underlying mechanism for the enhanced performance is also discussed. The symmetric sodium cells assembled with sintering aids modified Na3 Zr2 Si2 PO12 ceramic electrolyte exhibit ultra-stable metallic Na plating/stripping at room temperature. Moreover, solid-state sodium batteries paired with Na3 V1.5 Cr0.5 (PO4 )3 cathode active material and modified Na3 Zr2 Si2 PO12 ceramic electrolyte demonstrate superior cycling stability and excellent rate capability. Furthermore, an as-developed strategy can be universally extended to synthesize high-performance oxide ceramics.

17.
Microb Biotechnol ; 16(6): 1333-1343, 2023 06.
Article in English | MEDLINE | ID: mdl-36946330

ABSTRACT

R-1,3-butanediol (R-1,3-BDO) is an important chiral intermediate of penem and carbapenem synthesis. Among the different synthesis methods to obtain pure enantiomer R-1,3-BDO, oxidation-reduction cascades catalysed by enzymes are promising strategies for its production. Dehydrogenases have been used for the reduction step, but the enantio-selectivity is not high enough for further organic synthesis efforts. Here, a short-chain carbonyl reductase (LnRCR) was evaluated for the reduction step and developed via protein engineering. After docking result analysis with the substrate 4-hydroxy-2-butanone (4H2B), residues were selected for virtual mutagenesis, their substrate-binding energies were compared, and four sites were selected for saturation mutagenesis. High-throughput screening helped identify a Ser154Lys mutant which increased the catalytic efficiency by 115% compared to the parent enzyme. Computer-aided simulations indicated that after single residue replacement, movements in two flexible areas (VTDPAF and SVGFANK) facilitated the volumetric compression of the 4H2B-binding pocket. The number of hydrogen bonds between the stabilized 4H2B-binding pocket of the mutant enzyme and substrate was higher (from four to six) than the wild-type enzyme, while the substrate-binding energy was decreased (from -17.0 kJ/mol to -29.1 kJ/mol). Consequently, the catalytic efficiency increased by approximately 115% and enantio-selectivity increased from 95% to 99%. Our findings indicate that compact and stable substrate-binding pockets are critical for enzyme catalysis. Lastly, the utilization of a microbe expressing the Ser154Lys mutant enzyme was proven to be a robust process to conduct the oxidation-reduction cascade at larger scales.


Subject(s)
Alcohol Oxidoreductases , Butylene Glycols , Catalysis , Butylene Glycols/metabolism , Alcohol Oxidoreductases/chemistry , Kinetics , Substrate Specificity
18.
Materials (Basel) ; 16(6)2023 Mar 22.
Article in English | MEDLINE | ID: mdl-36984404

ABSTRACT

In this study, a modified chemical plugging agent is prepared with the aim to reduce the well moisture content and improve the efficiency of oilfield development. In comparison to other chemical plugging agents, the composite gels plugging agents have excellent blocking capacity and erosion resistance. In this study, optimal conditions for the preparation of plugging agents were explored. The results showed that the performance of polyacrylamide-sericite (PAM-sericite) gel improved at a polymerization temperature of 60 °C, a crosslinker concentration of 0.5%, an initiator concentration of 0.75%, an acrylamide concentration of 10.0%, and a sericite concentration of 10.0%. The characterization of PAM-sericite gel showed a certain fold-like shape with a smoother surface, indicating that the doped sericite makes the plugging agent more compact and firm. It was also found that the blocking ratio of the plugging agent can potentially reach 99.5% after the addition of sericite. Moreover, failure stress of the skeleton structure and the water swelling degree were increased by 63.5% and 51.2%, respectively. Additionally, long-term stability, temperature resistance, pressure resistance and pressure stability also showed improvement to varying degrees. It was concluded that this gel has better stability against different kinds of salt solutions and is not affected by particle size.

19.
ACS Appl Mater Interfaces ; 15(9): 11731-11740, 2023 Mar 08.
Article in English | MEDLINE | ID: mdl-36821726

ABSTRACT

The Z-scheme heterojunction shows great potential in photocatalysis due to its superior carrier separation efficiency and strong photoredox properties. However, how to regulate the charge separation at the nanometric interface of heterostructures still remains a challenge. Here, we take g-C3N4 and MoS2 as models and design the Mo-N chemical bond, which connects exactly the CB of MoS2 and VB of g-C3N4. Thus, the Mo-N bond could act as an atomic-level interfacial "bridge" that provides a direct migration path of charge carriers between g-C3N4 and MoS2. Experiments confirmed that the Mo-N bond and the internal electric field promote greatly the photogenerated carrier separation. The optimized photocatalyst exhibits a high hydrogen evolution rate that is about 19.6 times that of the pristine bulk C3N4. This study demonstrates the key role of an atomic-level interfacial chemical bond design in heterojunctions and provides a new idea for the design of efficient catalytic heterojunctions.

20.
Sci Total Environ ; 873: 162264, 2023 May 15.
Article in English | MEDLINE | ID: mdl-36842596

ABSTRACT

As a high-performance liquid rocket fuel, unsymmetrical dimethylhydrazine (UDMH) will produce wastewater during transportation, storage and cleaning containers. The wastewater will have a bad impact on human health and ecological environment, and it must be properly handled. There are many reports about the technical feasibility of UDMH wastewater treatment. Less attention is paid to analyzing the impact on the environment during the treatment process. This paper quantifies the environmental impacts and economic benefits of four advanced oxidation processes for the treatment of UDMH wastewater based on life cycle assessment and life cycle costing methods. Taking the UDMH wastewater produced by an aerospace group of Tianjin, China as the research object, using Fenton method, UV-Fenton method, electro catalytic oxidation (EC) with ruthenium iridium titanium (Ti/TiO2-RuO2-IrO2) as electrode and electro catalytic oxidation with boron-doped diamond (BDD) as electrode as treatment methods, on the basis of the laboratory test, the industrialized device is adopted. The resource consumption, energy consumption, pollutant discharge and cost were compared when the TOC removal rate was the same, and a better method of treating unsymmetrical dimethyl hydrazine wastewater was discussed. The results show that the impact on most types of environments is as follows: UV-Fenton < Fenton < EC (BDD) < EC (Ti/TiO2-RuO2-IrO2), and the four advanced oxidation methods are all beneficial to reduce eutrophication. The life cycle cost of UV-Fenton is the lowest (US$1.53/m3). Combined with environmental and economic analysis, it can be seen that UV-Fenton is the best choice. Through sensitivity analysis, it can be seen that reducing chemical reagents and electricity consumption, and changing the way of generating electricity to renewable energy can significantly reduce the environmental and economic impact. The life cycle cost of EC(BDD) as the electrode is the highest (US$26.20/m3), but it can achieve a TOC removal rate of 97.75 %, so it is a better choice when only the removal rate is required regardless of cost.

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