ACS Nano
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2019
·
IF 13.903
Shuang-Shuang Wan,Qian Cheng,Xuan Zeng,Xian-Zheng Zhang
Here, a Mn(III)-sealed metal–organic framework (MOF) nanosystem based on coordination between Mn(III) and porphyrin (TCPP) via a one-pot method was designed and constructed. Mn(III), as a sealer, not only quenched TCPP-based fluorescence but also inhibited reactive oxygen species (ROS) generation, which made MOFs an “inert” theranostic nanoparticle. Interestingly, upon endocytosis by tumor cells, MOFs were disintegrated into Mn(II) and free TCPP by intracellular glutathione (GSH) in tumor cells, owing to redox reaction between Mn(III) and GSH. This disintegration would lead to consumption of antioxidant GSH and activated Mn(II)-based magnetic resonance imaging (MRI) as well as TCPP-based fluorescent imaging. More importantly, such a GSH-regulated TCPP release could implement controllable ROS generation under irradiation, which avoided side effects (inflammation and damage of normal tissues). As a consequence, after unlocking by GSH, Mn(III)-sealed MOFs could significantly improve the therapeutic efficiency of photodynamic therapy by combining controlled ROS generation and GSH depletion after precise dual tumor homing.
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高影响因子
CATALYSIS COMMUNICATIONS
·
2022
·
IF 3.51
Haoxuan Wei,Jujiao Zhao,Md. Hasibur Rahaman,Quanfeng Wang,Jun Zhai
In this study, the catalytic activity of soluble Mn(III) ions, soluble Mn(III)-pyrophosphate (PP), and solid Mn(III) (α-MnO 2 ) towards peroxymonosulfate (PMS) activation was investigated through carbamazepine (CBZ) degradation. The degradation efficiency of CBZ was negligible when soluble Mn(III) ions or Mn(III)-PP were used as catalysts, while 99.7% of CBZ was degraded in the α-MnO 2 /PMS system with no soluble Mn(III) ions detected. The degradation efficiency of CBZ reduced by 18% with the solid Mn(III) content decreasing. Hence, the solid Mn(III) made the major contribution to PMS activation. This study supported a better understanding of the role of Mn(III) in PMS activation.
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International Journal of Environmental Research and Public Health
·
2022
·Vol. 19
·期 15
·9437
·
IF 4.614
Qianli Guo,Xianhu Qi,Jian Zhang,Bo Sun
Aqueous complexes of Mn(III) ion with ligands exist in various aquatic systems and many stages of water treatment works, while HSO3−is a common reductant in water treatment. This study discloses that their encounter results in a process that oxidizes organic contaminants rapidly. Pyrophosphate (PP, a nonredox active ligand) was used to prepare the Mn(III) solution. An approximate 71% removal of carbamazepine (CBZ) was achieved by the Mn(III)/HSO3−process at pH 7.0 within 20 s, while negligible CBZ was degraded by Mn(III) or HSO3−alone. The reactive species responsible for pollutant abatement in the Mn(III)/HSO3−process were SO4•−and HO•. The treatment efficiency of the Mn(III)/HSO3−process is highly related to the dosage of HSO3−because HSO3−acted as both the radical scavenger and precursor. The reaction of Mn(III) with HSO3−follows second-order reaction kinetics and the second-order rate constants ranged from 7.5 × 103to 17 M−1s−1under the reaction conditions of this study, suggesting that the Mn(III)/HSO3−process is an effective process for producing SO4•−. The pH and PP:Mn(III) ratio affect the reactivity of Mn(III) towards HSO3−. The water background constituents, such as Cl−and dissolved organic matter, induce considerable loss of the treatment efficiency in different ways.Keywords:Mn(III);bisulfite;advanced oxidation processes;sulfate radical;micropollutant abatement
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高影响因子
MATERIALS RESEARCH BULLETIN
·
2019
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IF 3.355
Lijun Zhu,Hao Cheng,Jianfeng Ma,Yong Kong,Yong Qin,Sridhar Komarneni
Decolorization of methyl orange (MO) by MnO 2 was investigated with and without small molecules of organic acids such as formic acid. It was found that the decolorization could be significantly improved by MnO 2 with the assistance of organic acids. The effect of various conditions was investigated on MO decolorization by using different crystal types of MnO 2 and changing the types of organic acids. One of the optimum treatment conditions was δ-MnO 2 /formic acid system, which led to the removal efficiency of 90.6% at 30 min. The pseudo-second-order kinetic rate constant of δ-MnO 2 /formic acid was 0.1626. A reasonable decolorization mechanism involving Mn(III) species was proposed and the mechanism was validated by simple detection of ionic species such as, Mn(II) and Mn(III) during the reaction. The δ-MnO 2 /formic acid process designed here may lead to a new advanced oxidation technology based on the in-situ generation of active Mn(III) species and their ability for oxidation.
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Water
·
2019
·Vol. 11
·期 11
·2302
·
IF 2.524
Dingyun Yan,Zhe Sun,Jiajie Wang,Lili Wang,Ruijun Pan,Qiang Wu,Xiaowei Liu
Mn(III) oxidation technology has attracted increasing interest in recent years because of its fast decontamination kinetics and second-pollution-free characteristic. Whether it can be used as a pre-oxidation step to enhance conventional coagulation process remains to be evaluated. Herein, an Fe-coagulation/sedimentation process combined with Mn(III) pre-oxidation (Mn(III)+C/S), hypochlorite pre-oxidation (Cl2+C/S), and permanganate pre-oxidation (PM+C/S) was applied to treat simulated micro-polluted raw water. The removal performance of routine water quality indices (turbidity, dissolved organic carbon, total nitrogen, nitrate-nitrogen, ammonia-nitrogen, Pb(II), and Cr(VI)) and the emerging pollutants (acesulfame, carbamazepine, bisphenol S, and nano-ZnO) created by these three processes were researched. The mechanism of how Mn(III) pre-oxidation influences C/S was explored by identifying the transformation products of Mn(III), measuring the timely variation of flocs’ zeta potential and size, and scanning flocs’ micromorphology. Compared to Cl2+C/S and PM+C/S, Mn(III)+C/S exhibited its superiority in removing dissolved organic carbon (72.9%), total nitrogen (31.74%), and emerging pollutants (21.78%–93.49%). The enhanced removal of these contaminants by Mn(III)+C/S found its explanation in the strong oxidation power of Mn(III) and the multiple roles of in-situ formed MnO2(e.g., flocculation core, adsorption co-precipitant, and densification agent). The acute toxicity tests confirmed that water treated by Mn(III)+C/S did not show a significant change in the associated toxicity. The findings of the present study indicate that Mn(III) oxidation technology shows great potential as an alternative to pre-oxidation technology of waterworks.Keywords:pre-oxidation;enhanced coagulation;Mn(III);emerging pollutants;micro-polluted raw water
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Journal of Earth Science
·
2019
·Vol. 30
·期 4
·861-869
·
IF 1.784
Zhang Caixiang,Liao Xiaoping,Lü You,Nan Chao
The ligand-stabilized soluble Mn(III) recognized as active intermediate can potentially mediate the attenuation of contaminants. In this study, the abiotic degradation behaviors of methyl parathion in the ligand stabilized Mn(III)-sulfite system were investigated. The results showed that the yield of soluble Mn(III) produced from the redox reaction of MnO 2 and oxalic acid was dependent linearly on the dosage of MnO 2 and caused the decomposition of methyl parathion up to 50.1% in Mn(III)-sulfite system after 30 minutes. The fitted pseudo-first-order reaction constants of methyl parathion degradation increased with the increasing of the amount of produced Mn(III) but was not effected linearly by the addition of sulfite. Other ligands, including pyrophosphate and oxalic acid, acted as effective complexing agents to stabilize soluble Mn(III), and exhibited competitive effect on methyl parathion degradation with sulfite. The formation of Mn(III)-sulfite complexes is the critical step in the system to produce abundant reactive oxygen species identified as SO 3 • - to facilitate methyl parathion degradation. The hydrolysis and oxidation of methyl parathion were acknowledged as two primary transformation mechanisms in Mn(III)-sulfite system. These findings indicate that naturally ligands-stabilized soluble Mn(III) can be generated and could oxidatively decompose organophosphate pesticides such as methyl parathion.
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Molecular Catalysis
·
2020
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IF 3.687
Anwei Wang,WeiYou Zhou,Zhonghua Sun,Zhong Zhang,Zhihui Zhang,MingYang He,Qun Chen
Developing efficient heterogeneous catalytic systems based on easily available materials and molecular oxygen for the selective oxidation of alkylarenes is highly desirable. In the present research, NiMn hydrotalcite (Ni 2 Mn-LDH) has been found as an efficient catalyst in the oxidation of alkylarenes using molecular oxygen as the sole oxidant without any additive. Impressive catalytic performance, excellent stability and recyclability, broad applicable scope and practical potential for the catalytic system have been observed. Mn 3+ species was proposed to be the efficient active site, and Ni 2+ played an important role in stabilizing the Mn 3+ species in the hydrotalcite structure. The kinetic study showed that the aerobic oxidation of diphenylmethane is a first-order reaction over Ni 2 Mn-LDH with the activation energy ( E a ) and pre-exponential factor ( A 0 ) being 85.7 kJ mol −1 and 1.8 × 10 9 min −1 , respectively. The Gibbs free energy (Δ G ≠ ) was determined to be -10.4 kJ mol -1 K -1 for the oxidation based on Eyring-Polanyi equation, indicating the reaction is exergonic. The mechanism study indicated that the reaction proceeded through both radical and carbocation intermediates. The two species were then trapped by molecular oxygen and H 2 O or hydroxyl species, respectively, to yield the corresponding products. The present research might provide information for constructing highly efficient and stable active site for the catalytic aerobic oxidation based on available and economic material.
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WATER RESEARCH
·
2017
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IF 6.942
Erdan Hu,Ya Zhang,Shuyan Wu,Jun Wu,Liyuan Liang,Feng He
Mn(III) is a strong oxidant for one electron transfer , which may be important in the transformation of organic contaminants during water/wastewater treatment and biogeochemical redox processes. This study explored the reaction mechanisms of dissolved Mn(III) with organics. The role of dissolved Mn(III) either as a catalyst or an oxidant in reactions with organics was recognized. Aquo and/or hydroxo (or free) Mn(III), generated from the bisulfite activated permanganate process, facilitated efficient N-dealkylation of atrazine via a β-elimination mechanism, resulting no net redox reaction. In contrast, free Mn(III) degraded 4-chlorophenol via intramolecular redox processes, the same as hydroxyl radical ( OH), resulting in dechlorination , OH substitution, ring-opening and mineralization. Mn(III)-pyrophosphate compounds did not react with atrazine because complexation by pyrophosphate rendered Mn(III) unable to bond with atrazine, thus the electron and proton transfers between the reactants couldn't occur. However, it degraded 4-chlorophenol at a slower rate compared to free Mn(III), due to its reduced oxidation potential. These results showed two distinct mechanisms on the degradation of organic contaminants and the insights may be applied in natural manganese-rich environments and water treatment processes with manganese compounds .
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高影响因子
SENSORS AND ACTUATORS B-CHEMICAL
·
2022
·
IF 9.221
Kun Yu,Guangyao Zhang,Huining Chai,Lijun Qu,Dan Shan,Xueji Zhang
Metal−organic frameworks (MOFs) have emerged as promising materials for smart sensing and imaging applications. Here, a novel micron-biscuit Mn(III)-based porphyrinic MOF is synthesized with the modulation of 4,4′-biphenyldicarboxylic acid (BPDC). The anisotropic growth of MOF is induced by the increased steric hindrance , yielding micron-biscuit Mn-TCPP(BPDC) MOF crystals. Mn(III), as a sealer, quenched the intrinsic fluorescence of porphyrin because of the ligand-to-metal charge transfer (LMCT) effect, and this disappeared fluorescence can be regularly restored and enhanced due to LMCT effect inhibition and release of free porphyrin derived from the water-induced two-stage ligand exchange (TSLE) between BPDC, porphyrin and water. The as-prepared MOF acts as an excellent “signal-on” luminescent water-sensing probe with low amount (2.5 μg/mL) that can efficiently realize the trace detection of water in various organic media with high sensitivity, especially in dimethyl sulfoxide (DMSO), the detection limit is as low as 0.04% (v/v). Moreover, Mn-TCPP(BPDC) was successfully used for sensing water content in real commercial samples. This MOF with the guest-induced TSLE not only provides inspiration for the design of new luminescent materials, but also widens the path for smart sensing.
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POLYHEDRON
·
2017
·
IF 1.926
Xiu-Mei Zhang,Jie Tang,Li-Na Wang,Di Yao,Qing Yu,Fu-Ping Huang,He-Dong Bian
Mimetics of superoxide dismutases (SOD), with certain ability to eliminate superoxide radicals under aerobic conditions, would be promising as drug candidates for antioxidant therapy. Many efforts have been devoted to synthesize small molecular compounds to mimic the functionality of natural SOD. In this paper, the Mn(III)/Co(III)/Fe(III) complexes have been synthesized with the Schiff base ligand (NaH 2 L), which was condensed from 2-hydroxynaphthalen-1-naphthaldehyde and 3,4-diaminobenzenesulfonic acid. The structures of complexes 1 and 3 have been determined by X-ray crystallographic method, and all the complexes have been investigated using FT-IR, MS. The binding constants between metal complexes and bovine serum albumin (BSA) have been determined by fluorescence spectroscopy. Meanwhile, we have synthesized 3 hybrid proteins through the interaction of the complexes and BSA. The SOD-like activity was tested by xanthine/xanthine oxidase method. The result shows that BSA molecule can increase the SOD activity of the transition metal complexes.
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Journal of Materials Chemistry B
·
2021
·Vol. 9
·期 15
·3401-3411
·
IF 6.331
Ming Wang,Miao Li,Yunli Wang,Yiran Shao,Yingchun Zhu,Shiping Yang
Hydroxyapatite (HA) has attracted wide attention for medical application due to its biocompatibility and bioactivity. However, the infection problems of HA remain among the leading reasons for implantation failure. Thus, it is urgent to endow HA biomaterials with antibacterial activity. Herein, the high antibacterial activity was achieved by introducing trace Mn3+ and H vacancy couples in HA through a facile heat-treatment strategy in air. The theoretical results indicated that Mn3+ was preferentially substituted for the Ca(2) site in the HA structure with a charge-compensating H vacancy appearing at the adjacent OH− site. The antibacterial tests showed that Mn-HA possessed antibacterial activity towards both E. coli and S. aureus with trace Mn content at the ppm level, and implied that Mn3+ and centers may play an important role in the antibacterial process. The Mn3+ and couples in Mn-HA, serving as oxidative and reductive centers respectively, could then collectively participate in the CoQ/CoQH2 redox cycling and synergistically facilitate the accumulation of CoQ˙− and ROS radicals. This enhanced ROS production was the main factor to endow Mn-HA with efficient antibacterial activity. Moreover, the in vitro bioactivity assay showed that Mn-HA materials exhibited enhanced osteogenic activity and good biocompatibility. Therefore, this work not only provides a feasible method to control the oxidation state of Mn elements in HA, but also proposes a novel trace Mn3+-doped HA for potential applications in tissue engineering.
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Journal of Environmental Chemical Engineering
·
2023
·
IF 7.7
Yiqing Liu,Ting Wang,Zhengjie Chen,Shenglan Liu,Yongsheng Fu
Currently, the research on bisulfite (BS) activation by Mn(II) is very limited probably because of the low catalytic efficiency of Mn(II). Adding ligands to Mn(II)/BS system is likely to improve the BS activation, but the relative information is very rare. Therefore, the effect of nitrilotriacetic acid (NTA) on Mn(II)/BS system was investigated in this work using sulfamethoxazole (SMX) as the target contaminant. The results showed that the addition of NTA enhanced SMX removal in Mn(Ⅱ)/BS system through forming Mn(Ⅱ/III)-NTA complexes driving Mn(III)/Mn(II) cycle and stabilizing Mn(III). Alcohol scavenging experiments and competitive kinetic experiments indicated that sulfate radical (SO 4 •− ) and hydroxyl radical (HO • ) were not the main reactive species in Mn(II)/NTA/BS system. Mn(Ⅲ) was the primary oxidant for SMX elimination in this system and its existence was proved by UV-Vis absorption spectrum of reaction solution. Mn(Ⅱ)/NTA/BS system could greatly degrade SMX in near-neutral conditions, while nearly no SMX removal was observed at pH 3.0. The decrease of dissolved oxygen concentration significantly inhibited BS autocatalytic stage, thus suppressing the removal of SMX. Due to the competitive complexation of HCO 3 − and FA with NTA for Mn(II), their addition in Mn(Ⅱ)/NTA/BS system obviously inhibited SMX degradation . Four intermediates were detected during SMX degradation in Mn(Ⅱ)/NTA/BS system, and the possible SMX transformation pathways were speculated as N-S bond breaking, hydroxylation, amino oxidation and coupling reaction.
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