Latest ArticlesThe textile industry spreads globally with the challenges of its wastewater treatment, especially dyes, which are difficult to degrade. To improve coagulation-flocculation process in dye wastewater treatment, an intercalation process was employed to prepare a new efficient coagulant of lithium borohydride-iron oxychloride (LiBH4_FeOCl) in this study. The layered crystal pristine iron oxychloride (FeOCl) material was prepared by chemical gas phase migration. LiBH4 was introduced into the layers of two dimensional (2D) FeOCl nanosheets by a simple method of liquid phase insertion. The samples were characterized by a field emitting scanning electron microscopy (SEM), a rotating anode X-ray powder diffractometer (XRD), etc. The cationic dye was employed as the simulated pollutant. A coagulation and decolorization experimental device was built to study the coagulation performance of the new coagulant LiBH4_FeOCl. It is found that the intercalation modified LiBH4_FeOCl exhibits the characteristics of crystal structure, and the layered structure of FeOCl is preserved. LiBH4_FeOCl, as an insoluble inorganic solid coagulant, performs well for dye pollutants of methyl red, basic yellow 1, methylene blue, rhodamine B, ethyl violet and Janus green B. The reaction rate is significantly 68% higher than the current commercial coagulants of Al2(SO4)3. The mechanism analysis reveals that LiBH4_FeOCl breaks and disperses rapidly in the water environment. Its negatively charged material particles can be electrostatically adsorbed with dye pollutant molecules through electrostatic action. The above collaborative actions of breaking, dispersion and electrostatic adsorption are the main coagulation mechanisms of LiBH4_FeOCl. The solid inorganic coagulant of LiBH4_FeOCl provides a competitive alternative for traditional inorganic salts and organic coagulants.
Morphology and dispersity are key factors for activating peroxymonosulfate (PMS). In this study, we designed a recyclable open-type NiCo2O4 hollow microsphere via a simple hydrothermal method with the assistance of an NH3 vesicle. The physical structure and chemical properties were characterized using techniques such as scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), N2 adsorption and X-ray photoelectron spectroscopy (XPS). The test results confirm that the inner and outer surfaces of open-type NiCo2O4 hollow-sphere can be efficiently utilized because of the hole on the surface of the catalyst, which can minimize the diffusion resistance of the reactants and products. Under optimized conditions, the total organic carbon (TOC) removal efficiency of rhodamine B (RhB) can reach up to 80% in 40 min, which is almost 50% shorter than the reported values. The reactive radicals were identified and the proposed reaction mechanism was well described. Moreover, the disturbances of HCO3−, NO3−, Cl− and H2PO4− were further investigated. As a result, HCO3− and NO3− suppressed the reaction while Cl− and H2PO4− had a double effect on reaction.
Visible-light-driven photochemical Cadogan-type cyclization has been discovered. The organic D-A type photosensitizer 4CzIPN found to be an efficient mediator to transfer energy from photons to the transient intermediate that breaks the barriers of deoxygenation in Cadogan reaction and enables a mild metal-free access to carbazoles and related heterocycles. DFT calculation results indicate mildly endergonic formation of the intermediate complex of nitrobiarenes and PPh3, which corresponds with experimental findings regarding reaction temperature. The robust synthetic capacity of the photoredox Cadogan reaction systems has been demonstrated by the viable productivity of a broad range of carbazoles and related N-heterocycles with good tolerance of various functionalities.
In power storage technology, ion exchange is widely used to modify the electronic structures of electrode materials to stimulate their electrochemical properties. Here, we proposed a multistep ion exchange (cation exchange and anion exchange) strategy to synthesize amorphous Ni-Co-S and β-Co(OH)2 hybrid nanomaterials with a hollow polyhedron structures. The synergistic effects of different components and the remarkable superiorities of hollow structure endow Ni-Co-S/Co(OH)2 electrode with outstanding electrochemical performance, including ultra-high specific capacity (1440.0 C/g at 1 A/g), superior capacitance retention rate (79.1% retention at 20 A/g) and long operating lifespan (81.4% retention after 5000 cycles). Moreover, the corresponding hybrid supercapacitor enjoys a high energy density of 58.4 Wh/kg at the power density of 0.8 kW/kg, and a decent cyclability that the capacitances are maintained at 80.8% compared with the initial capacitance. This research presents a high-performance electrode material and provides a promising route for the construction of electrode materials for supercapacitors with both structural and component advantages.
Prussian whites (PWs) with a three-dimensional framework can accommodate the insertion and extraction of ions with large radius, which have been widely used in potassium ion batteries. However, PWs show the poor cycling performance and inferior rate ability because of high coordinated water. In this work, PWs with different water content were synthesized via a coprecipitation method by controlling the reaction temperature. The sample with low-coordination water prohibits the best electrochemical performance. It shows a high capacity of 120.5 mAh/g at 100 mA/g for potassium-ion batteries (KIBs). It also exhibits a good rate performance, displaying a capacity of 73.2 mAh/g at 500 mA/g.
Fabrication of well-designed heterojunctions is an extraordinarily attractive pathway for boosting the photocatalytic activity toward CO2 photoreduction. Herein, a novel kind of nanosheet-based intercalation hybrid coupled with CdSe quantum dots (QDs) was successfully fabricated by a facile solvothermal method and served as photocatalyst for full-spectrum-light-driven CO2 reduction. Ultra-small CdSe QDs were rationally in-situ introduced and coupled with lamellar ZnSe-intercalation hybrid nanosheet, resulting in the formation of CdSe QDs/ZnSe hybrid heterojunction. Significantly, the concentration of Cd2+ could change directly the crystallinity and micromorphology of ZnSe intercalation hybrid, which in turn would impact on the photocatalysis activity. The optimized CdSe QDs/ZnSe hybrid-5 composite demonstrated a considerable CO yield rate of the 25.6 μmol g-1 h-1 without any additional cocatalysts or sacrificial agents assisting, making it one of the best reported performance toward CO2 photoreduction under full-spectrum light. The elevated CO2 photoreduction activity could be attributed to the special surface heterojunction, leading to improving the ability of light absorption and promoting the separation/transfer of photogenerated carriers. This present study developed a new strategy for designing inorganic-organic heterojunctions with enhanced photocatalyst for CO2 photoreduction and provided an available way to simultaneously mitigate the greenhouse effect and alleviate energy shortage pressure.
DNA methyltransferase (DNMT) and histone deacetylase (HDAC) are well recognized epigenetic targets for discovery of antitumor agents. In this study, we designed and synthesized a series of nucleoside base hydroxamic acid derivatives as DNMT and HDAC dual inhibitors. MTT assays and enzymatic inhibitory activity tests indicated that compound 204 exhibited potent DNMT1 and HDAC1/6 inhibitory potency simultaneously in enzymatic levels and at cellular levels, inducing hypomethylation of p16 and hyperacetylation of histones H3K9 and H4K8. Besides, 204 remarkably inhibited proliferation against cancer cells U937 by prompting G0/G1 cell cycle arrest. Molecular docking models explained the functional mechanism of 204 inhibiting DNMT1 and HDAC. Preliminary studies on metabolic profiles revealed that 204 showed desirable stability in liver microsomes. Our study suggested that 204 inhibiting DNMT and HDAC concurrently can be a potential lead compound for epigenetic cancer therapy.
Supramolecular transformations of coordination cage or capsule have received much attention recently, which help elucidate this natural self-assembly behavior in biological systems. The current study describes the first supramolecular transformation of titanium–organic coordination capsule triggered by phenol (and H3PO3). The structural alterations are accompanied by the reconstruction of 5-coordinated Ti centers to 6-coordinated ones. Meanwhile, different amounts of encapsulated phenol guest molecules can be identified, dependent on the sizes of the obtained cavities. In addition, they display much better visible light absorption and air stability than the isopropanol stabilized ones.
Different from traditional metal-support heterogenous catalysts, inverse heterogeneous catalysts, in which the surface of metal is decorated by metal oxide, have recently attracted increasing interests owing to the unique interfacial effect and electronic structure. However, a deep insight into the effect of metal-oxide interaction on the catalytic performance still remains a great challenge. In our work, an inverse hematite/palladium (Fe2O3/Pd) hybrid nanostructure, i.e., the active Fe2O3 ultrathin oxide layers partially covering on the surface of Pd nanoparticles (NPs), exhibited superior electrocatalytic performance towards methanol oxidation reaction (MOR) as compared to the bare Pd NPs based on density functional theory calculation. The charge could transfer from Pd to Fe2O3 driven by the built-in potential at the interface of Pd and Fe2O3, which favors the downshift of d band center of Pd. With the assistance of interfacial hydroxyl OH*, the cleavage of OH and CH in CH3OH could take place much easily with lower barrier energy on Fe2O3/Pd than that on pure Pd via two electrons transferring reaction pathways. Our results highlight that the synergy of Pd and Fe2O3 at the interface could facilitate the electrochemical transformation of methanol into formaldehyde assisted with interfacial hydroxyl OH*.
Microbial fuel cells (MFCs) have various potential applications. However, anode is a main bottleneck that limits electricity production performance of MFCs. Herein, we developed a novel anode based on a stainless steel cloth (SC) modified with carbon nanoparticles of Chinese ink (CI) using polypyrrole (PPy) as a building block (PPy/CI/SC). After modification, PPy/CI/SC showed a 30% shorten in start-up time (36.4 ± 3.3 h vs. 52.3 ± 1.8 h), 33% increase in the maximum current (12.4 ± 1.4 mA vs. 9.3 ± 0.95 mA), and 2.3 times higher in the maximum power density of MFC (61.9 mW/m2 vs. 27.3 mW/m2), compared to Ppy/SC. Experimental results revealed that carbon nanoparticles were able to cover SC uniformly, owing to excellent dispersibility of carbon nanoparticles in CI. The attachment of carbon nanoparticles formed a fluffy layer on SC increased the electrochemically-active surface area by 1.9 times to 44.5 cm2. This enhanced electron transfer between the electrode and bacteria. Further, embedding carbon nanoparticles into the PPy layer significantly improved biocompatibility as well as changed functional group contents, which were beneficial to bacteria adhesion on electrodes. Taking advantage of high mechanical strength and good conductivity, a large-size PPy/CI/SC was successfully prepared (50 × 60 cm2) demonstrating a promising potential in practical applications. This simple fabrication strategy offers a new idea of developing low cost and scalable electrode materials for high-performance energy harvesting in MFCs.