JOURNAL OF HAZARDOUS MATERIALS
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2023
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IF 13.6
Yang Zong,Hua Zhang,Hao Liu,Jun Xu,Zhengwei Zhou,Xiaomeng Zhang,Ting Zhang,Deli Wu
Mn(II) is among the most efficient catalysts for the periodate (PI)-based oxidation process . In-situ formed colloidal MnO 2 simultaneously serves as the catalyst and oxidant during the degradation of organic contaminants by PI. Here, it is revealed that the complexation of Mn(II) by ethylene diamine tetraacetic acid (EDTA) further enhances the performance of PI-based oxidation in the selective degradation of organic contaminants. As evidenced by methyl phenyl sulfoxide probing, 18 O-isotope labeling, and mass spectroscopy , EDTA complexation modulates the reaction pathway between Mn(II) and PI, triggering the generation of high-valent manganese–oxo (Mn V –oxo) as the dominant reactive species. PI mediates the single-electron oxidation of Mn(II) to Mn(III), which is stabilized by EDTA complexation and then further oxidized by PI via the oxygen-atom transfer step, ultimately producing the Mn V –oxo species. Ligands analogous to EDTA, namely, [S,S]-ethylenediaminedisuccinic acid and L -glutamic acid N , N -diacetic acid, also enhances the Mn(II)/PI process and favors Mn V –oxo as the dominant species. This study demonstrates that functional ligands can tune the efficiency and reaction pathways of Mn(II)-catalyzed peroxide and peroxyacid-based oxidation processes.
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Small
·
2023
·
IF 13.3
Xiao Gong,Qingqing Xu,Jiurong Li,Yan Ma,Xiaoyan Li,Wanze Wu,Hangxiang Wang
The aggregation-caused quenching has always limited the high concentration and solid-state applications of carbon nanodots. While the aggregation-induced emission effect, dominated by intramolecular motion, may be an effective means to solve this problem. Here, hydrophobic solid-state red-light carbon nanodots (M-CDs) with 95% yield are synthesized by a one-step hydrothermal method using 2,2'-dithiodibenzoic acid as the carbon source and manganese acetate as the dopant source. The disulfide bond of 2,2'-dithiodibenzoic acid serves as the symmetry center of molecular rotation and Mn catalyzes the synthesis of M-CDs, which promotes the formation of the central graphitic carbon structure. The M-CDs/agar hydrogel composites can achieve fluorescence transition behavior because of the special fluorescence transition properties of M-CDs. When this composite hydrogel is placed in water, water molecules contact with M-CDs through the network structure of the hydrogels, making the aggregated hydrogels of M-CDs fluorescence orange-red under 365 nm excitation. While in dimethyl sulfoxide, water molecules in the hydrogels network are replaced and the M-CDs fluoresce blue when dispersed, providing a potential application in information encryption. In addition, high-performance monochromatic light-emitting diode (LED) devices are prepared by compounding M-CDs with epoxy resin and coating them on 365 nm LED chips.
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WATER RESEARCH
·
2023
·
IF 12.8
Xuecong Qian,Shilong Wang,Haijun Cheng,Ziye Jia,Da Wang,Yandong Xie,Jinhao Duan,Yu Tian,Jun Ma
The oxidation kinetics of Mn(II) by free chlorine is relatively low under near-neutral pH conditions which limits the Mn removal efficiency in drinking water treatment. Therefore, this study investigated the oxidation efficiency of Mn(II) by the UV-enhanced chlorination (UV/chlorine) system and identified the responsible reactive radical species. The results show that the oxidation kinetic of Mn(II) was greatly enhanced by the UV/chlorine system under near-neutral pH or even acidic conditions. The pseudo-first-order reaction rate of Mn(II) at pH 8.0 (within the first 20 min) increased from 2.60 × 10 −5 s −1 to 3.41 × 10 −4 s −1 . Based on the scavenging experiments and the steady-state kinetic modeling, ClO · and ClO 2 , whose steady-state concentration (∼10 −10 M and ∼10 −9 M, respectively at pH 8.0) was at least 4 orders of magnitude higher than that of HO · and Cl · , were recognized as the dominant reactive species contributing to the oxidation of Mn(II). Kinetic model calculations indicate that the contribution of ClO · to the oxidation of Mn(II) was consistently maintained above 70 %, and ClO 2 also played an important role in the oxidation of Mn(II) especially under acidic and alkaline conditions. In addition, the background components of HCO 3 − and Cl − had negligible influence on the oxidation efficiency because they barely changed the concentration of the ClO · and ClO 2 . This study first demonstrates the important role of ClO 2 in the oxidation of Mn(II) in the UV/chlorine system, and the possible role of ClO 2 in the degradation of some organic pollutants needs to be carefully evaluated in the future.
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CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Kang-Hui Hu,Chao-Qiong Zhu,Bao-Ping Zheng,Lang Qiu,Fang Wan,Yang Song,Ben-He Zhong,Zhen-Guo Wu,Xiao-Dong Guo
Li-rich Mn-based oxide cathodes are one of the most promising cathode candidates for high energy density over 400 Wh kg −1 , deriving from oxygen redox of Li-O-Li configuration. However, the deep oxygen oxidation would lead to the formation of peroxides and superoxides (O 2 n − , 0 < n ≤ 2) and even oxygen (O 2 ), accompanied by crystal phase transformation and structure collapse. Herein, an integrative strategy of simultaneously regulating the right amount of oxygen vacancies (OVs) and B-atom doping is proposed to achieve differentially modification of both R-3 m and C2/m phases. Firstly, Rietveld refinement, HRTEM and in situ XRD results reveal that the linear increase of OVs content is achieved by regulating the amount of BN and the selective introduction of OVs inside the C2/m phase makes the oxygen partial pressure lower in the weak O-Li-O bonds of TM-layer and inhibits oxygen release at over 4.5 V. Meanwhile, kinetics test shows oxygen defects would accelerate the Li + diffusion and reduce the electronic impedance driven by uneven local charge distribution. Secondly, lattice analysis shows the strong covalent B-O bonds located at the tetrahedral site not only prevent the overoxidation of the oxygen atoms at high voltage, but also hinder the migration of Mn atoms through tetrahedral sites, which effectively avoids the damage of the crystal structure. As a result, the modified cathode exhibits the excellent discharge specific capacity of 272 mA h g −1 at 0.1C, higher rate performance of 145 mA h g −1 at 5C, an outstanding capacity retention rate of 93% at 1C and lower voltage decay value of 0.43 V after 200 cycles. This promising strategy could simultaneously achieve both high energy density and superior cycling stability and help to advance industrial application of Li-rich Mn-based Cathodes.
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CHEMICAL ENGINEERING JOURNAL
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2023
·
IF 15.1
Yue Zhao,Rui Gao,He Wang,Yanping Sun,Xiaohui Zhan,Lei Chen,Junyan Liu,Huixiang Shi
The adsorption and protective calcination methods were combined to synthesize single Mn atoms catalyst with more Mn-N x exposure for peroxymonosulfate (PMS) activation. During the carbonization process, the surface adsorbed Mn species in zeolitic imidazolate framework-8 (ZIF-8) and the surrounding graphitic carbon nitride (g-C 3 N 4 ) jointly maintained the morphology of precursor and enriched Mn-N 6 sites near the catalyst surface. The hollow and hierarchically porous structures induced by the erosive function of g-C 3 N 4 further facilitated the exposure of Mn-N 6 sites and mass transfer processes. Herein, the derived hollow carbon polyhedron catalyst (C-Z8-Mn@g-C 3 N 4 ) possessed highly accessible edge-host Mn-N 6 sites and ultra-high specific surface area (1846.91 m 2 g −1 ). C-Z8-Mn@g-C 3 N 4 exhibited remarkable catalysis for sulfamethoxazole (SMX) degradation at an extremely low dosage (0.01 g L −1 ), particularly, up to 3.8 times of promotion was obtained compared to traditional single Mn atoms catalyst (66.9 vs 17.8 L g −1 min −1 ). Besides, the catalytic performance of C-Z8-Mn@g-C 3 N 4 was not obviously affected by initial pH (3.14–11.00), inorganic anions and natural organic matters (NOMs). Experiments and Density functional theory (DFT) calculations revealed that Mn-N 6 sites not only had stronger PMS adsorption capacity than graphitic N, but also enhanced the electron transfer between catalyst and PMS, thus promoting the redox and self-decomposition of PMS to produce SO 4 − , OH and singlet oxygen ( 1 O 2 ) (as major active oxygen species). This work provides new insights into the regulation of active sites exposure in single-atom catalysts for enhanced catalytic performance.
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APPLIED CATALYSIS B-ENVIRONMENTAL
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2023
·
IF 22.1
Wang Song,Qianni Cheng,Li Han,Jiawei Ji,Yandi Cai,Wei Tan,Jingfang Sun,Changjin Tang,Lin Dong
Manganese oxide-based catalysts exhibit excellent low-temperature denitration efficiency, making them potential candidates for application. Herein, the relationship between reaction stability and phase structure for MnO 2 , Mn 2 O 3 and Mn 3 O 4 was disclosed. The NO conversion for Mn 2 O 3 drastically reduced after 120 h reaction, while minor decline was detected for MnO 2 and Mn 3 O 4 . Based on dedicate qualitative and quantitative analyses on the deposits over catalyst surface, deactivation trigged by ammonium nitrate (AN) deposition was confirmed. Different from penta-coordinated Mn 4+ on MnO 2 (110) and tri-coordinated Mn 2+ , penta-coordinated Mn 4+ on Mn 3 O 4 (101), the unique tetra-coordinated Mn 3+ on Mn 2 O 3 (200) could stabilize the nitrates and make it difficult to be removed via decomposition or reaction and accumulate continuously, which resulted in the significant deactivation. This research could not only unveil the poisoning mechanism of MnO x based catalysts, but also provide new insights into the relationship between the catalytic stability and surface Mn-O microstructure.
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ACS Applied Materials & Interfaces
·
2023
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IF 9.5
Bangxiang Liu,Hengjia Zhu,Jinjin Liu,Mengzhu Wang,Jianming Pan,Rulin Feng,Panwang Hu,Xiangheng Niu
As a typical antibiotic pollutant, tetracycline (TC) is producing increasing threats to the ecosystem and human health, and exploring convenient means for monitoring of TC is needed. Here, we proposed alkali-etched imprinted Mn-based Prussian blue analogues featuring superior oxidase-mimetic activity and precise recognition for the colorimetric sensing of TC. Simply etching Mn-based Prussian blue analogues (Mn-PBAs) with NaOH could expose the sites and surfaces to significantly improve their catalytic activity. Density functional theory calculations were employed to screen the molecularly imprinted polymer (MIP) layer for target identification. Consequently, the designed Mn-PBANaOH@MIP possessed the rich channels for substrates to get in touch with the active Mn-PBANaOH core, showing an excellent catalytic capacity to trigger the chromogenic oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) without the use of H2O2. If TC was introduced, it would be recognized selectively by the MIP shell and masked the channels for TMB access, resulting in the obstruction of the chromogenic reaction. According to this mechanism, selective optical detection of TC was achieved, and performance stability, reusability, and reliability as well as practicability were also verified, promising potential for TC monitoring in complex matrices. Our work not only presents an effective way to enhance the enzyme-like activity of Prussian blue analogues but also provides a facile approach for TC sensing. Additionally, the work will inspire the exploration of molecularly imprinted nanozymes for various applications.
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SEPARATION AND PURIFICATION TECHNOLOGY
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2023
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IF 8.6
Bing Li,Fulin Deng,Zheyu Li,Hao Xiong,Shuqu Zhang,Weili Dai,Jie Zhang,Lixia Yang,Jianping Zou,Xubiao Luo
Perovskite oxide, as a promising candidate for volatile organic compounds combustion, is incapable in practical application at present due to its low intrinsic activity resulting from inadequate active oxygen species. However, balancing the concentration of active oxygen species and robust structure for perovskite oxide is still challenging. Herein, an efficient perovskite-based catalyst (denoted as TA-La 0.9 Ag 0.1 MnO 3 ) was constructed through Ag substitution and subsequently tartaric acid etching of LaMnO 3 , which exhibits robustly boosted catalytic performance for toluene combustion compared with pristine LaMnO 3 , causing a ∼100 °C lower T 90 . In this study, Ag substitution could weaken the La-O hybridization, which effectively facilitates La cations removal by subsequent acid etching, thus sufficiently exposing active Ag and Mn species and generating more surface lattice oxygen, but also constructs Ag-Mn-O bridges within the matrix of Ag substituted LaMnO 3 . Acid etching enables the activation of Ag-O-Mn bridges with strong electron transfer ability from O to Ag atom, promoting the mobility of lattice oxygen, and consequently the low-temperature oxidation ability. Additionally, the exposed Ag and Mn as Lewis acid sites can effectively improve the adsorption capacity toward toluene molecules, which synergistically facilitates the toluene abatement. Notably, TA-La 0.9 Ag 0.1 MnO 3 also exhibits superb long-term stability, water-resistance, and high thermal stability up to 650 °C.
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Materials Chemistry Frontiers
·
2023
·Vol. 7
·期 17
·3728-3737
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IF 7
Xiaohu Guo,Ke Yue,Jiale Zheng,Zaoli Yu,Yao Wang,Yujing Liu,Tiefeng Liu,Jianmin Luo,Xinyong Tao,Jianwei Nai
Improving overall water electrolysis efficiency is challenging due to difficulties in designing high-efficiency, non-noble metal oxygen evolution electrocatalysts. The key to success lies in improving the electrocatalyst's specific surface area and optimizing its electronic structure. In this study, a novel method for obtaining coronal manganese cobalt Prussian blue analogues (MnCo PBA) with high specific surface area was developed through simple chemical etching. The MnSe/CoSe2 composite, derived from coronal MnCo PBA, retains the high specific area characteristics of the precursor. The resulting coronal MnSe/CoSe2 demonstrates excellent OER performance, attributed to the high specific area composite MnSe/CoSe2, which exposes more active sites and promotes synergistic effects between its components. The overpotential at a current density of 10 mA cm−2 is 360 mV, and the electrocatalyst displays long-term stability of up to 200 hours. This work offers a unique and effective approach to designing high-performance OER electrocatalysts.
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Catalysts
·
2023
·Vol. 13
·期 3
·529
·
IF 3.9
Linshuang Xue,Chenyi Yuan,Shipeng Wu,Zhen Huang,Zhen Yan,Stéphane Streiff,Hualong Xu,Wei Shen
Coalbed methane is a significant source of methane in the atmosphere, which is a potent greenhouse gas with a considerable contribution to global warming, thus it is of great importance to remove methane in coalbed gas before the emission. Exploring the economical non-noble metal catalysts for catalytic methane combustion (CMC) has been a wide concern to mitigate the greenhouse effect caused by the emitted low-concentration methane. Herein, a series of Mn-doped Co3O4catalysts have been synthesized by the environmentally friendly solid-state method. As a result, the Mn0.05Co1catalyst performed the best CMC activity (T90= 370 °C) and good moisture tolerance (3 vol% steam). The introduction of an appropriate amount of manganese conduced Co3O4lattice distortion and transformed Co3+to Co2+, thus producing more active oxygen vacancies. Mn0.05Co1exhibited better reducibility and oxygen mobility. In situ studies revealed that methane was adsorbed and oxidized much easier on Mn0.05Co1, which is the crucial reason for its superior catalytic performance.Keywords:active oxygen;catalytic combustion;low-concentration;methane;Mn-Co3O4;solid-state
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CHEMICAL ENGINEERING JOURNAL
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2023
·
IF 15.1
Lixia Jia,Qi Zhou,Yuanwei Li,Weizhong Wu
In this study, Mn-C composites using different MnO 2 contents and solid carbon material were prepared to explore the synchronous removal performance of nutrients and SMX. Higher nitrate removal performance (97–98 %) with quickest nitrate removal rate (4.97 mg N L -1 h −1 ) was obtained in Mn_20 systems. The increased Mn content and Mn-P compound were observed via surface characteristics, indicating the involvement of MnOx in pollutants removal , particularly for higher phosphorus removal (84–89 %) via Mn-P precipitation and BioMnOx adsorption. Nevertheless, compared to systems based on Mn_0 composites (74 %), systems with Mn-C composites presented lower SMX reduction efficiency (34–51 %), which might be attributed to the large Mn(II) accumulation, impairing certain microbes and lower the MnOx function. Higher abundance of genera affiliated to Bacteroidetes_vadinHA17 and Rhodocyclaceae was observed in the Mn-C composites, as well as the gathering of Geobacter and Desulfovibrio as keystone taxa, responsible for the removal of nitrate and SMX and microbial interactions. Besides, the increase of sulfonamide ARGs was closely related to the predominant microbes in the Mn-C composites, which acted as the hosts of ARGs. This study broadens the knowledge of Mn-C composites in synergetic removal of nutrients and organics, and supports the potential application of manganese oxide in wastewater treatment.
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ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2023
·Vol. 30
·期 23
·64233-64245
·
IF 5.8
Jin Qi,Dong Yingbo,Pan Hanlin,Lin Hai
It is challenging to separate the materials for treating arsenic contamination of soil and water from systems. The natural magnetite covered with Fe–Mn bimetallic (oxyhydr)oxide (Fe–Mn MSM) was effectively created in this study, and its potential use in removing As from water and soil was investigated. Batch adsorption studies showed that the As(V) adsorption on Fe–Mn MSM could achieve equilibrium after 120 min when the initial As(V) concentration was 39.85 mg/L. The calculated maximum adsorption of Fe–Mn MSM for As(V) was 17.94 mg/g at 20 °C. The mechanism of As(V) adsorption was confirmed to be a combination of ligand exchange and electrostatic attraction by the outcomes of FTIR analysis, SEM, and batch adsorption tests. Fe–Mn MSM can also be a successful amendment for cleaning up As-polluted soil. The 5% Fe–Mn MSM treatment group had the lowest exchangeable fraction of As (EX-As) concentration, 0.039 mg/kg (8.3% of initial EX-As), after 40 days. Magnetic separation could be used to quickly and completely recover the used Fe–Mn MSM from the soil. EX-As was present in higher concentrations on Fe–Mn MSM than that of the original soil. As a result, this work offers a strategy that may be put into practice to cheaply remove As from soil and water while also encouraging the reuse of natural magnetite. Graphical abstract
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危险品化学品经营许可证（带存储）