Latest ArticlesNanoplastics exhibit greater environmental biotoxicity than microplastics and can be ingested by humans through major routes such as tap water, bottled water and other drinking water. Nanoplastics present a challenge for air flotation due to their minute particle size, negative surface potential, and similar density to water. This study employed dodecyltrimethylammonium chloride (DTAC) as a modifier to improve conventional air flotation, which significantly enhanced the removal of polystyrene nanoplastics (PSNPs). Conventional air flotation removed only 3.09% of PSNPs, while air flotation modified by dodecyltrimethylammonium chloride (DTAC-modified air flotation) increased the removal of PSNPs to 98.05%. The analysis of the DTAC-modified air flotation mechanism was conducted using a combination of instruments, including a zeta potential analyzer, contact angle meter, laser particle size meter, high definition camera, scanning electron microscope (SEM), energy dispersive spectrometer (EDS) and Fourier transform infrared spectrometer (FTIR). The results indicated that the incorporation of DTAC reversed the electrostatic repulsion between bubbles and PSNPs to electrostatic attraction, significantly enhancing the hydrophobic force in the system. This, in turn, improved the collision adhesion effect between bubbles and PSNPs. The experimental results indicated that even when the flotation time was reduced to 7 min, the DTAC-modified air flotation still achieved a high removal rate of 96.26%. Furthermore, changes in aeration, pH, and ionic strength did not significantly affect the performance of the modified air flotation for the removal of PSNPs. The removal rate of PSNPs in all three water bodies exceeded 95%. The DTAC-modified air flotation has excellent resistance to interference from complex conditions and shows great potential for practical application.
Hyperglycemia resulting from diabetes mellitus (DM) exacerbates osteoporosis and fractures, damaging bone regeneration due to impaired healing capacity. Stem cell therapy offers the potential for bone repair, accelerating the healing of bone defects by introducing stem cells with osteogenic differentiation ability. Dental follicle stem cells (DFSCs) are a newly emerging type of dental stem cells that not only have the potential for multipotent differentiation but also hold easy accessibility and can stand long-term storage. However, DM-associated oxidative stress and inflammation elevate the risk of DFSCs dysfunction and apoptosis, diminishing stem cell therapy efficacy. Recent nanomaterial advances, particularly in DNA nanostructures like tetrahedral framework nucleic acids (tFNAs), have been promising candidates for modulating cellular behaviors. Accumulating experiments have shown that tFNAs' cell proliferation and migration-promoting ability and induce osteogenic differentiation of stem cells. Meanwhile, tFNAs can scavenge reactive oxygen species (ROS) and downregulate the secretion of inflammatory factors by inhibiting various inflammation-related signaling pathways. Here, we applied tFNAs to modify DFSCs and observed enhanced osteogenic differentiation alongside ROS scavenging and anti-inflammatory effects mediated by suppressing the ROS/mitogen-activated protein kinases (MAPKs)/nuclear factor kappa-B (NF-κB) signaling pathway. This intervention reduced stem cell apoptosis, bolstering stem cell therapy efficacy in DM. Our study establishes a simple yet potent tFNAs-DFSCs system, offering potential as a bone repair agent for future DM treatment.
Bridged bicyclic cores have been recognized as valuable bioisosteres of benzene ring, which are of great value in medicinal chemistry. However, the development of fluorinated bicyclic skeletons, which encompass two privileged elements widely acknowledged for fine tuning the working effect of target molecules, are far less common. Herein, we present a general and practical synthesis of gem–difluorobicyclo[2.1.1]hexanes (diF-BCHs) from readily available difluorinated hexa-1,5-dienes through energy transfer photocatalysis. By taking advantage of an efficient Cope rearrangement, the preparation of both constitutional isomers of diF-BCHs is readily achieved under identical conditions. The operational simplicity, mild conditions and wide scope further highlight the potential application of this protocol. Moreover, computational studies indicated a positive effect of fluorine atoms in lowering either the triplet or FMO energies of the hexa-1,5-diene substrates, thus promoting the present photoinduced [2 + 2] cycloaddition.
Here we present a highly efficient protocol utilizing nickel-hydride hydrogen atom transfer catalysis for the regio- and enantioselective hydrofluorination of internal alkenes. This method efficiently assembles a wide array of enantioenriched β-fluoro amides with excellent regio- and enantioselectivity from internal unactivated alkenes. Mechanistic investigations suggest that this transformation proceeds via a NiH-hydrogen atom transfer to alkene, followed by a stereoselective fluorine atom transfer process. The weak coordination effect of the tethered amide group is identified as a crucial factor governing the observed regio- and enantioselectivity.
As a versatile and environmentally benign oxidant, hydrogen peroxide (H2O2) is highly desired in sanitation, disinfection, environmental remediation, and the chemical industry. Compared with the conventional anthraquinone process, the electrosynthesis of H2O2 through the two-electron oxygen reduction reaction (2e− ORR) is an efficient, competitive, and promising avenue. Electrocatalysts and devices are two core factors in 2e− ORR, but the design principles of catalysts for different pH conditions and the development trends of relevant synthesis devices remain unclear. To this end, this review adopts a multiscale perspective to summarize recent advancements in the design principles, catalytic mechanisms, and application prospects of 2e− ORR catalysts, with a particular focus on the influence of pH conditions, aiming at providing guidance for the selective design of advanced 2e− ORR catalysts for highly-efficient H2O2 production. Moreover, in response to diverse on-site application demands, we elaborate on the evolution of H2O2 electrosynthesis devices, from rotating ring-disk electrodes and H-type cells to diverse flow-type cells. We elaborate on their characteristics and shortcomings, which can be beneficial for their further upgrades and customized applications. These insights may inspire the rational design of innovative catalysts and devices with high performance and wide serviceability for large-scale implementations.
Humic acid (HA), as a represent of natural organic matter widely existing in water body, dose harm to water quality and human health; however, it was commonly treated as an environmental background substance while not targeted contaminant in advanced oxidation processes (AOPs). Herein, we investigated the removal of HA in the alkali-activated biochar (KBC)/peroxymonosulfate (PMS) system. The modification of the original biochar (BC) resulted in an increased adsorption capacity and catalytic activity due to the introduction of more micropores, mesopores, and oxygen-containing functional groups, particularly carbonyl groups. Mechanistic insights indicated that HA is primarily chemically adsorbed on the KBC surface, while singlet oxygen (1O2) produced by the PMS decomposition served as the major reactive species for the degradation of HA. An underlying synergistic adsorption and oxidation mechanism involving a local high concentration reaction region around the KBC interface was then proposed. This work not only provides a cost-effective solution for the elimination of HA but also advances our understanding of the nonradical oxidation at the biochar interface.
Developing efficient, non-toxic, and low-cost emitters is a key issue in promoting the applications of electrochemiluminescence (ECL). Among varied ECL emitters, polymeric emitters are attracting dramatically increasing interest due to tunable structure, large surface area, brilliant transfer capability, and sustainable raw materials. In this review, we present a general overview of recent advances in developing polymeric luminophores, including their structural and synthetic methodologies. Methods rooted in straightforward unique structural modulation have been comprehensively summarized, aiming at enhancing the efficiency of ECL along with the underlying kinetic mechanisms. Moreover, as several conjugated polymers were just discovered in recent years, promising prospects and perspectives have also been deliberated. The insight of this review may provide a new avenue for helping develop advanced conjugated polymer ECL emitters and decode ECL applications.
Perovskite oxides have been widely applied as an effective catalyst in heterogeneous catalysis. However, the rational design of active catalysts has been restricted by the lack of understanding of the electronic structure. The correlations between surface properties and bulk electronic structure have been ignored. Herein, a simple handler of LaFeO3 with diluted HNO3 was employed to tune the electronic structure and catalytic properties. Experimental analysis and theoretical calculations elucidate that acid etching could raise the Fe valence and enhance Fe–O covalency in the octahedral structure, thereby lessening charge transfer energy. Enhanced Fe–O covalency could lower oxygen vacancy formation energy and enhance oxygen mobility. In-situ DRIFTS results indicated the inherent adsorption capability of Toluene and CO molecules has been greatly improved owing to higher Fe–O covalency. As compared, the catalysts after acid etching exhibited higher catalytic activity, and the T90 had a great reduction of 45 and 58 ℃ for toluene and CO oxidation, respectively. A deeper understanding of electronic structure in perovskite oxides may inspire the design of high-performance catalysts.
Rational tuning of crystallographic surface and metal doping were effective to enhance the catalytic performance of metal organic frameworks, but limited work has been explored for achieving modulation of crystal facets and metal doping in a single system. MIL-68(In) was promising for photocatalytic applications due to its low toxicity and excellent photoresponsivity. However, its catalytic activity was constrained by severe carrier recombination and a lack of active sites. Herein, increased (001) facet ratio and active sites exposure were simultaneously realized by cobalt doping in MIL-68(In) through a one-pot solvothermal strategy. Optimized MIL-68(In/Co)-2.5 exhibited remarkable catalytic performance in comparison with pristine MIL-68(In) and other MIL-68(In/Co). The reaction kinetic constant and degradation efficiency of MIL-68(In/Co) were approximately twice and 17% higher than the pristine MIL-68(In) in 36 min reaction, respectively. Density functional theory calculations revealed that Co dopant could modulate the orientation of MIL-68(In) facets, facilitate the exchange of electrons and reduce the adsorption energy of peroxymonosulfate (PMS). This work provides a novel pathway for improvement of In-based MOFs in PMS/vis system, it also promotes the profound comprehension of the correlation between crystal facet regulation and catalytic activation in the PMS/vis system.
Algal copper uptake (i.e., Cu bioavailability) in the euphotic zone plays a vital role in algal photosynthesis and respiration, affecting the primary productivity and the source and sink of atmospheric carbon. Algal Cu uptake is controlled by natural dissolved organic Cu (DOCu) speciation (i.e., complexed with the dissolved organic matter) that conventionally could be tested by model prediction or molecular-level characterizations in the lab, while DOCu uptake are hardly directly assessed. Thus, the new chemistry-biology insight into the mechanisms of the Cu uptake process in algae is urgent. The DOCu speciation transformation (organic DOCu to free Cu(Ⅱ) ions), enzymatic reduction-induced valence change (reduction of free Cu(Ⅱ) to Cu(Ⅰ) ions), and algal Cu uptake at the algae-water interface are imitated. Herein, an intelligent system with DOCu colorimetric sensor is developed for real-time monitoring of newly generated Cu(Ⅰ) ions. Deep learning with whole sample image-based characterization and powerful feature extraction capabilities facilitates colorimetric measurement. In this context, the Cu bioavailability with 7 kinds of organic ligands (e.g., amino acids, organic acids, carbohydrates) can be predicted by the mimetic intelligent biosensor within 15.0 min, i.e., the DOCu uptake and speciation is successfully predicted and streamlined by the biomimetic approach.
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