Preparation of MnO2 Loaded Hydrothermal Carbon-coated Electrospun PAN Fiber Membranes for Highly Efficient Adsorption and Separation of Cationic Dye

Hydrothermal carbonaceous materials and MnO₂ have been proved to be promising adsorbents to remove organic dyes from wastewater. In this study, flexible MnO₂ loaded hydrothermal carbon-coated electrospun poly-acrylonitrile(AC/MnO₂/PAN) fiber membranes were fabricated by a facile one-step hydrothermal method and activated by NaOH solution. The composite fibers exhibited large adsorption capacity toward cationic dyes and excellent mechanical properties. The adsorption performance can be fitted well with pseudo-second-order model and Langmuir isotherm model. The maximum adsorption for methylene blue(MB), methyl violet(MV) and malachite green(MG) are 1173.27,1106.31 and 1129.89 mg/g, respectively, according to Langmuir fitting. The AC/MnO₂/PAN fiber membrane also showed satisfactory performances for selective adsorption and recyclability. In addition, based on selective adsorption, the AC/MnO₂/PAN fiber membranes that are repulsive to the anionic dye methyl orange(MO) can separate the MB/MO mixture solution by dynamic filtration. Thus, this work not only provides a facile strategy to fabricate large capacity adsorbents, but also demonstrates the potential applications in the dye wastewater treatment field.     

Thermal hazard assessment and ranking for organic peroxides using quantitative structure–property relationship approaches

Journal of Thermal Analysis and Calorimetry - Chemical reactivity hazards of organic peroxides are major concerns of the chemical industry due to many serious incidents every year. Thermal hazard...     

New cadinane sesquiterpenoids from Mikania micrantha

Abstract

Chemical investigation of the aerial parts of Mikania micrantha led to the isolation of eight sesquiterpenoids and ten diterpenoids, including five cadinane sesquiterpenoids (1?5), three bisabolene sesquiterpenoids (6???8), nine ent-kaurane diterpenoids (9–17), and an abietane diterpenoid (18). Among them, 1???3 are new and feature a rare lactone or furan ring derived from C-6 isopropyl group side chain. Compound 18 was isolated from genus Mikania for the first time, and was also the first example of abietane-type diterpenoids from this plant. Their structures were elucidated on the basis of extensive spectroscopic analyses (1D and 2D NMR, HRESIMS, and ECD). All compounds were examined for their inhibitory effects on lipopolysaccharide (LPS)-induced nitric oxide (NO) production in RAW 264.7 macrophage cells, and compound 18 exhibited pronounced inhibition on NO production (IC₅₀ = 11.04?µM), being comparable to the positive control, quercetin (IC₅₀ = 11.15?µM).     

Flavonoids from the leaves of Epimedium Koreanum Nakai and their potential cytotoxic activities

Abstract

Phytochemical studies on the leaves of Epimedium koreanum Nakai have resulted in the discovery of two new flavonol glycosides, koreanoside F (1) and koreanoside G (2), along with six known flavonoids. Their structures were elucidated on the basis of HRESIMS, UV, IR, 1?D NMR and 2?D NMR data. Absolute configurations of 1 and 2 was further determined by ¹³C-NMR spectra with gate decoupling (GD). All of the compounds were evaluated for cytotoxic activities by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazoliumbromide (MTT) assay. The results indicated that compounds 3, 5, 6, 7 and 8 inhibited the proliferation of A549 and NCI-292 cells with IC₅₀ values of 5.7–23.5?μM. Real-time monitoring in three kinds of lung cancer cells and a kind of human bronchial epithelial cells treated with compound 6 was also assessed.     

Photoredox/palladium-cocatalyzed enantioselective alkylation of secondary benzyl carbonates with 4-alkyl-1,4-dihydropyridines

A photoredox/palladium-cocatalyzed enantioselective alkylation of racemic secondary carbonates with 4-alkyl-1,4-dihydropyridines under visible light irradiation has been developed. The present study provides a method for the preparation of optically active diarylalkanes from racemic diarylmethyl carbonates by a dynamic kinetic asymmetric transformation(DYKAT).This photoredox/palladium dual catalysis strategy expands the scope of the asymmetric Pd-catalyzed benzylic substitution reaction and serves as its potential alternative and complement.     

低压供热涂层材料制备及热性能研究

低压供热技术具有安全系数高和节能降耗等优势,因而成为石化稠油长输管线、风力发电叶片冬季防覆冰和室内供暖等领域的研究热点之一。本文制备了一系列低压供热涂层材料,研究不同碳功能填料对涂层发热速率、发热功率及最高发热温度的影响规律,并揭示石墨烯和碳纤维对提升涂层材料热性能的协同作用。其中石墨烯纳米片的还原程度对材料热性能具有重要影响,降低其表面官能团密度对提升涂层供热特性具有促进作用,但是官能团密度过低会导致石墨烯纳米片的团聚现象,引起涂层发热不均匀。加入适量碳纤维可以提高石墨烯的均匀分散性,提升发热速率。优化石墨烯纳米片和碳纤维的比例后,采用24V电压驱动时,涂层材料的发热速率达到7.1℃·s^-1,功率密度为800W·m^-2,最高发热温度为124℃。     

Tributylstibine-mediated olefination of carbonyl compounds with bromomalonic ester and with dibromomalonic ester—A possible pathway through a stibonium ylide via halophilic initiation by tertiary stibines

Tributylstibine can mediate the olefination of carbonyl compounds with bromomalonic ester and with dibromomalonic ester. An initial halophilic attack of tributylstibine on the bromine of bromomalonic or dibromomalonic ester forming an ion pair of bromotributylstibonium cation and malonic (A) or bromomalonic ester carbanion (B) , respectively, is proposed. These ion pairs react with carbonyl compounds to achieve subsequent olefination. Alternatively, 2 equiv of A collapse, with elimination of malonic ester, to form stiborane D , and the ion pair B reacts with another equivalent of tributylstibine to form stiborane D. This last undergoes a Wittig-type reaction with carbonyl compound to achieve olefination.     

Experimental review of the ϒ(1S, 2S, 3S) physics at e+e− colliders and the LHC

The three lowest-lying \mathrm{\Upsilon } states, i.e., \mathrm{\Upsilon }(1S), \mathrm{\Upsilon }(2S), and \mathrm{\Upsilon }(3S), composed of bb¯ pairs and below the BB ¯ threshold, provide a good platform for the researches of hadronic physics and physics beyond the Standard Model. They can be produced directly in e⁺e⁻ colliding experiments, such as CLEO, Babar, and Belle, with low continuum backgrounds. In these experiments, many measurements of the exclusive \mathrm{\Upsilon }(1S) and \mathrm{\Upsilon }(2S) decays into light hadrons, which shed light on the “80% rule” for the Okubo–Zweig–Iizuka suppressed decays in the bottomonium sector, were carried out. Meanwhile, many studies of the charmonium and bottomonium productions in \mathrm{\Upsilon }(1S, 2S, 3S) decays were performed, to distinguish different Quantum Chromodynamics (QCD) models. Besides, exotic states and new physics were also extensively explored in \mathrm{\Upsilon }(1S, 2S, 3S) decays at CLEO, BaBar, and Belle. The \mathrm{\Upsilon }(1S, 2S, 3S) states can also be produced in pp collisions and in collisions involving heavy ions. The precision measurements of their cross sections and polarizations at the large hadron collider (LHC), especially in the CMS, ATLAS, and LHCb experiments, help to understandΥproduction mechanisms in pp collisions. The observation of the sequentialΥsuppression in heavy ion collisions at CMS, LHCb, and ALICE is of great importance for verifying the quark–gluon plasma predicted by QCD. In this article, we review the experimental results on \mathrm{\Upsilon }(1S, 2S, 3S) at e⁺e⁻ colliders and the LHC, and summarize their prospects at Belle II and the LHC.     

Grinding-assisted heterogeneous nucleation of BiOAc on MoS2 nanoflowers to heterojunction with good visible-light photocatalytic performance

Bismuth oxide subacetate(CH3COO(BiO);BiOAc)with a large band gap energy(Eg)was first applied as an ultraviolet-light-driven photocatalyst in our group.MoS2 nano...