Abstract A simple fluorescent probe, ( E )‐ N ‐(3‐methoxy‐4‐methylphenyl)‐1‐(quinolin‐2‐yl)methanimine ( L ), was synthesized via Schiff base condensation reaction between quinoline‐2‐carboxaldehyde and 3‐methoxy‐4‐methylaniline. L can be used as a ′turn‐on′ fluorescent probe for the selective and sensitive detection of Zn 2+ ions in a CH 3 OH/HEPES medium. The detection limit was 1.04×10 −7 M. Job plot analysis shows that the binding stoichiometry of L and Zn 2+ is 1 : 1, further verified by the single crystal structure. The fluorescence‐enhanced response of L towards Zn 2+ ions may be related to the chelation‐enhanced fluorescence (CHEF) supported by theoretical calculations. By adding EDTA, the reversibility of the probe binding to Zn 2+ ions is demonstrated, enabling the construction of a functional molecular logic circuit. In addition, probe L was successfully incorporated into test strips for the quantitative detection of Zn 2+ .
In this study, the oxidative removal of Mn(II) by peroxymonosulfate (PMS) was investigated. PMS was found to be a more efficient oxidant than chlorine for Mn(II) oxidation. A weak autocatalysis kinetics was observed in PMS/Mn(II) system suggesting that the Mn(II) oxidation consisted of both homogeneous (direct oxidation) and heterogeneous (amorphous MnO 2 catalytic oxidation) processes. Homogeneous oxidation of Mn(II) by PMS showed strong pH dependency with apparent second-order rate constants of 3.1-249.9 M -1 s -1 at pH 7.0-9.0. Stoichiometry of PMS to Mn(II) was about 1:1 suggesting a two-electron transfer pathway (O transfer), which was further confirmed by the XPS analysis results. However, the change of coordination structure of Mn(II) was found to greatly affect the oxidation rate and mechanism of Mn(II). Complexion with inorganic or organic ligands could inhibit the oxidation rate of Mn(II) and alter the oxidation mechanism from two-electron to one-electron pathway. Furthermore, coexisting metal ions such as Ca(II), Zn(II), and Fe(II)/Fe(III) ions could greatly accelerate the oxidation of Mn(II) by PMS and chlorine via promoting the heterogeneous oxidation process. Oxidative removal of Mn(II) by PMS was more efficient than chlorine in real waters (56%-100% versus 12%-17%). The combination of PMS oxidation with coagulation could further increase the removal efficiency from 56% to 92%. These findings highlight that PMS oxidation is an attractive alternative technology for Mn(II) removal and may also provide a fundamental understanding of the Mn-based materials advanced oxidation processes.
In the title compound, C(26)H(25)ClN(4)O(3)S, the acyclic imine group exhibits an E configuration. The triazole ring is oriented at dihedral angles of 53.84 (2), 70.77 (1) and 32.59 (3)° with respect to the benzene rings of the 2-chloro-benzyl-idene, 4-methyl-benzyl-sulfanyl and 3,4,5-trimethoxy-phenyl groups, respectively. The crystal packing is stabilized by weak inter-molecular C-H⋯N, C-H⋯S and C-H⋯π inter-actions.
In this work, the mechanism of the activation of peroxides by quinones has been investigated through quantum chemical calculations. Hydrogen peroxide (H2O2), peroxomonosulfate (PMS), peracetic acid (PAA), and CH3OOH were chosen as the model peroxides and p-benzoquinone (p-BQ) and tetrachloro-1,4-benzoquinone (TCBQ) as the model quinones. The nucleophilic attack of peroxides can occur on the carbonyl and olefinic carbons of quinones. For p-BQ, the nucleophilic attack of HO2–, CH3OO–, PMS, and PAA might prefer to occur on the carbonyl carbons, which have more positive atomic charges. Then, further transformation could not be induced from the addition of HO2– and CH3OO– to p-BQ. Comparatively, singlet oxygen (1O2) could be generated in the cases of PMS and PAA. For TCBQ, the chlorine atoms cause the olefinic carbons to carry more positive atomic charges, and then, HO2– preferred to add to the olefinic carbons, which might induce the formation of the hydroxyl radical (•OH). The activation of PMS by TCBQ was similar to that by p-BQ, with the kinetical feasibility of 1O2 formation. These findings may provide some theoretical insights into the reaction of peroxides with quinones, especially into the interconnection between the substitutes and the formation of oxygen-centered radicals (e.g., •OH) and 1O2.
As a deep connection between agriculture and energy, the rural integrated energy system (RIES) is a micro-scale supply–distribution–storage–demand network, which provides an important means to realize the utilization of rural clean energy. This paper proposes a day-ahead scheduling model of the RIES to improve its economical effectiveness, where three energy carriers, namely, biogas, electric power, and heat, are integrated. To address the source and load uncertainties composed of photovoltaic power, power load, and heat load, this paper develops a constrained distributionally robust optimization (CDRO), which optimizes the cost expectation related to the extreme distribution to enhance the robustness, while limiting the loss of cost expectation in the historical distribution to ensure economical effectiveness. In addition, an ambiguous set of the source and load uncertainties incorporating 1-norm and infinity-norm constraints is established, which realizes a flexible adjustment for the conservativeness of CDRO. The distributionally robust dispatch is formulated as a deterministic programming in a two-stage solving framework, where the subproblem uploads its extreme probability distribution to the master problem, and these two problems are iteratively optimized until the convergence. Finally, the numerical simulations in a modern farm park prove the performance of the constructed dispatch model and the flexibility of CDRO in balancing the economical effectiveness and robustness of the dispatch.
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