CHEMOSPHERE
·
2023
·
IF 8.8
Yiqiao Zhang,Bo Sun,Dandan Rao,Jian Zhang,Shuang Liang
Permanganate (MnO 4 − ), an oxidant that has been applied in water treatment , has highly varied reactivity toward pollutants. In this study, we found manganate (MnO 4 2− ) could destruct diverse functional groups, with oxidation rates being higher than that of permanganate under acidic and neutral conditions. Mechanistic study revealed manganate rapidly disproportionated to permanganate and colloidal MnO 2 in solution. Under acidic conditions, the in-situ formed colloidal MnO 2 possess higher reactivity than permanganate and primarily contributed to the degradation of pollutants. The reactivity of in-situ formed colloidal MnO 2 is highly sensitive to pH and decreased dramatically with increasing pH. Consequently, the contribution of MnO 2 to pollutant removal decreased with elevating pH, which also leads to the decreased degradation efficiency of micropollutants at high pH. Manganate is an intermediate produced during the manufacturing process of permanganate. This study indicates that manganate might be an alternative of permanganate for water purification under acidic and neutral conditions.
研究领域:
环境科学
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水处理化学
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污染物降解
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DOI
PubMed
高影响因子
INTERNATIONAL JOURNAL OF THERMOPHYSICS
·
2018
·Vol. 39
·期 5
·1-11
·
IF 0.829
Fan Desong,Sun Si,Guo Li
A novel thermal control coating was presented based on the thermochromism of manganite. The pigment of K-doped manganite nanoparticles was dispersed into polymer matrix to prepare the coating with curing below 200 \(^{\circ }\) C. The nanoparticles size mainly distributes around 100–200 nm, and it shows a comparable stoichiometric ratio. The phase transition of the nanoparticles was observed from ferromagnetic metallic to paramagnetic insulator state. With increasing K doping level, the phase transition temperature increases, achieving controllable adjustment. Coating surface with and without pore defect was obtained by different polymer matrix. A sharp emittance variation was observed with increasing temperature in K-doped coating. The variation magnitude of emittance is up to 0.46, which is attractive to space thermal control. It is suggested that the pigment content of 50 wt% is sufficient to realize a large emittance variation.
研究领域:
材料科学
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航天工程
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产品关联
DOI
高影响因子
Frontiers of Environmental Science & Engineering
·
2022
·Vol. 16
·期 8
·1-11
·
IF 6.048
Dong Lei,Xie Pin,Zhang Xin,Qiao Junlian,Rao Dandan,Sun Yuankui,Guan Xiaohong
The permanganate (Mn(VII)) oxidation has emerged as a promising technology for the remediation and treatment of the groundwater and surface water contaminated with the organic compounds. Nonetheless, only a few studies have been conducted to explore the role of the heavy metals (especially the redox-active ones) during the Mn(VII) oxidation process. In this study, taking Pb(II) as an example, its influence on the Mn(VII) decontamination performance has been extensively investigated. It was found that, with the presence of Pb(II), Mn(VII) could degrade diclofenac (DCF), 2,4-dichlorophenol, and aniline more effectively than without. For instance, over a wide pH range of 4.5–8.0, the dosing of 10 µmol/L Pb(II) accelerated the DCF removal rate from 0.006–0.25 min −1 to 0.05–0.46 min −1 with a promotion factor of 1.9–9.4. Although the UV-vis spectroscopic and high resolution transmission electron microscopy analyses suggested that Mn(VII) could react with Pb(II) to produce Mn(IV) and Pb(IV) at pH 6.0–8.0, further experiments revealed that Pb(II) did not exert its enhancing effect through promoting the generation of MnO 2 , as the reactivity of MnO 2 was poor under the employed pH range. At pH below 5.0, it was interesting to find that, a negligible amount of MnO 2 was formed in the Mn(VII)/Pb(II) system in the absence of contaminants, while once MnO 2 was generated in the presence of contaminants, it could catalyze the Pb(II) oxidation to Pb(IV) by Mn(VII). Collectively, by highlighting the conversion process of Pb(II) to Pb(IV) by either Mn(VII) or MnO 2 , the reactive Pb(III) intermediates were proposed to account for the Pb(II) enhancement effect.
研究领域:
环境科学
·
化学
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DOI
高影响因子
ACS ES&T Engineering
·
2023
·
IF 7.1
Beiping Zhang,Chaoting Guan,Qin Guo,Run Huang,Jin Jiang
Electrochemical technologies and permanganate oxidation are two attractive strategies in water treatment due to their low cost, easy operation, good adaptability, and environmental friendliness. Interestingly, recent studies have demonstrated that the combination of electrolysis and Mn(VII) (E-Mn(VII) process) shows a synergetic effect on organic contaminants degradation. However, the underlying mechanism of the E-Mn(VII) process remains unclear. In this study, the enhanced removal of diclofenac (DCF) by the E-Mn(VII) process was also demonstrated, and the main reactive species were reidentified. It was found that H2O2 was considerably formed via the reduction of O2 on the cathode, and it played a key role in facilitating Mn(VII) transformation into MnO2. Increasing O2 concentration, working potential, and pH value were conducive to H2O2 formation as well as Mn(VII) transformation to MnO2. Higher Mn(VII) dosages did not impact H2O2 formation but also led to faster MnO2 formation. The enhanced formation of MnO2 was favorable for the fast degradation of DCF in the E-Mn(VII) process owing to the catalytic effect of MnO2 on Mn(VII) oxidation. This was confirmed by the observation that (i) the E-Mn(VII) process showed a similar pH-dependent oxidation trend to that of MnO2 catalytic oxidation of Mn(VII) (i.e., the reactivity was much stronger at lower pH); and (ii) the addition of MnO2 prepared ex situ had a significant enhancing effect on DCF oxidation by the E-Mn(VII) process. Moreover, the possible contribution of reactive manganese intermediates such as soluble free Mn(III), Mn(VI), and Mn(V) was ruled out by the results of the probe experiments, UV–visible spectrophotometry, and examining the reactivity of Mn(III) complexes prepared ex situ. Also, the results of radical scavenging experiments indicated the negligible contribution of HO•. Furthermore, for the practical application of the E-Mn(VII) process in water decontamination, suitable operating parameters (e.g., a moderate potential and relatively lower pH) should be determined to avoid the fast loss of Mn(VII) and the electrical energy consumption. Overall, this work brings new insights into the reaction mechanism of the E-Mn(VII) process as well as proposes an efficient, sustainable, and feasible strategy for water and wastewater treatment.
研究领域:
环境科学
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化学工程
·
水处理
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电化学
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产品关联
DOI
高影响因子
CHEMOSPHERE
·
2021
·
IF 7.086
Siyang Sun,Yuhan Wang,Lin Zhou,Xiaoyu Wang,Chunli Kang
In this study, we constructed MnO 2 /organic acid (OA) systems using MnO 2 colloid, the most reactive phase of Mn(IV), and two kinds of OA (oxalic acid and l -tartaric acid). We investigated the effect of OA on tetracycline (TC) degradation by MnO 2 . The results show that both OA obviously accelerate TC degradation by MnO 2 . Mn(III) formed during the reaction lead to the acceleration. Mn(III)-oxalate complex formed in oxalic acid system resulted in the lower degradation efficiency than that in l -tartaric acid system. The acceleration of oxalic acid was decreased when the concentration was more than 75 μM, and even completely disappeared with the concentration of 500 μM, owning to the fact that excess oxalic acid decreased the pH and some MnO 2 was fast reduced to Mn 2+ by oxalic acid and unable to react with TC. The impact of pH on TC degradation resulted from the influences of H + on MnO 2 redox potentials and TC deprotonation. And acidic conditions accelerated TC degradation. The addition of Mg 2+ , Ca 2+ , Fe 3+ and Zn 2+ exhibited an inhibitory effect in both systems for their occupying reactive sites on MnO 2 surface and blocking the access of TC to MnO 2 . Similar intermediates in the two systems were detected, indicating a similar TC degradation mechanism including a series of reactions like dehydration, hydroxylation and oxidation. The MnO 2 /OA system provides an efficient treatment of TC in wastewater. And it is also noticeable that MnO 2 /OA system should also have an important effect on the fate of pollutants in environment, from our results.
研究领域:
环境科学
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化学
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DOI
高影响因子
Separations
·
2024
·Vol. 11
·期 9
·274
·
IF 2.5
Wenjun Xu,Qianyi Wang,Jintao He,Fuzhen Liu,Xiang Yan,Yin Xu
The development of appropriate and effective periodate (PI) activation technology is currently a popular research area. This study presents a novel efficient photocatalytic activation approach of PI for pollutant degradation based on carbon nitride (g-C3N4) and visible light (Vis). The results show that the system can remove 92.3% of acid orange 7 (AO7) within 60 min under the g-C3N4/PI/Vis reaction system. The degradation rate constant (kobs) reached 4.08 × 10−2min−1, which is 4.21,5.16 times, and 51.3 times higher than that of the g-C3N4/Vis system (9.7 × 10−3min−1), PI/Vis system (7.9 × 10−3min−1) and the g-C3N4/PI system (7.96 × 10−4min−1), respectively. Clearly, the addition of PI significantly enhances the degradation efficiency of AO7 in the system. Additionally, under the same reaction conditions, the presence of PI showed excellent oxidation capacity in the photoactivation process compared with other common oxidants, such as peroxymonosulfate, peroxydisulfate, and H2O2. Moreover, the g-C3N4/PI/Vis system showed excellent removal of AO7 across a wide range of pH levels and in the presence of various anions. Electron paramagnetic resonance (EPR) and quenching experiments suggested that the superoxide anions (•O2−) and singlet oxygen (1O2) dominated in the oxidation of pollutants in the g-C3N4/PI/Vis system. In addition, the catalyst showed relative stability during cyclic testing, although a slight reduction in degradation efficiency was observed. In brief, the g-C3N4/PI/Vis system is highly efficient and environmentally friendly, with significant application potential in wastewater treatment.
研究领域:
环境科学
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化学工程
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产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2018
·
IF 6.735
Chen Li,Hui Lin,Andac Armutlulu,Ruzhen Xie,Yongli Zhang,Xiaoyang Meng
In this study, ferrate (Fe(VI)) was used as catalyst to activate persulfate (PS) for the removal of ciprofloxacin (CIP) from aqueous solution. Hydroxylamine (HA) was used to accelerate the reduction and regeneration of Fe(II) from the Fe(VI) + PS system. It was found that 91.5% of 30 μM CIP was decomposed within 60 min in the PS + Fe(VI)/HA system, which is 25.9% higher than that in the PS + Fe(VI) system. In the PS + Fe(VI)/HA system, the removal of CIP increased with the decrement of initial solution pH, whereas inorganic anions (i.e. HCO 3 − , Cl − , NO 3 − ions) and humic acid had slightly inhibitory effects on CIP removal. The radical scavenging experiments and the electron paramagnetic resonance (ESR) tests confirmed that the addition of HA in the PS + Fe(VI) system can accelerate the generation of reactive oxygen species (ROS) such as sulfate radicals (SO 4 − ) and hydroxyl radicals ( OH), which played important roles for the removal of CIP in the PS + Fe(VI)/HA system. CIP degradation intermediates were also identified and the pathways were proposed. This study suggested a new approach for catalytic degradation of CIP by ferrate.
研究领域:
环境科学
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化学
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产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2016
·
IF 3.299
Xiaodan Zhao,Jun Ma,Jin Jiang,Yuhuan Bao,Huiling Liu
Synergistic enhancement of phenols and anilines removal was investigated in permanganate oxidation in the presence of multi-walled carbon nanotubes (CNTs). Then the attendant dehalogenation was explored for bromophenols and bromoanilines from the perspective of dehalogenation number (DN). Permanganate decay and total manganese concentration decrease in the presence of CNTs indicates considerable formation of manganese dioxide (MnO 2 ) on carbon surface. The CNTs-enhanced phenol degradation is more favorable under lower pH, confirming that the generation of MnO 2 induced by the reaction between permanganate and CNTs enhances the phenol oxidation by permanganate. The first order rate constants of respective bromophenols and bromoanilines suggest the synergistic enhancement of CNTs and permanganate in removing these micropollutants. Bromide release experiments clearly demonstrate that the subsequent dehalogenation accompanying the oxidation of bromophenols and bromoanilines is significant for permanganate oxidation in the absence/presence of CNTs. Dehalogenation by permanganate follows the order of 4-bromophenol > 2-bromophenol > 3-bromophenol and 4-bromoaniline > 2-bromoaniline > 3-bromoaniline, respectively. Higher DN values in the presence of CNTs indicate a reduced dehalogenation. In real water application, permanganate in the presence of CNTs could effectively remove 4-bromoaniline with a maximum removal efficiency of ∼95% and a bromide release of 2 μM.
研究领域:
环境科学
·
化学工程
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产品关联
DOI
高影响因子
WATER RESEARCH
·
2022
·
IF 13.4
Zheng-Yu Dong,Yi-Li Lin,Tian-Yang Zhang,Chen-Yan Hu,Yang Pan,Zheng-Xiong Zheng,Yu-Lin Tang,Bin Xu,Nai-Yun Gao
Permanganate (Mn(VII)) is widely used as a mild oxidant in water treatment. However, the reaction rates of some emerging contaminants with Mn(VII) are extremely low. In this study, benzoquinone (BQ), a redox mediator with the important component in dissolved organic matter (DOM), enhanced the oxidation of bisphenol A (BPA) by Mn(VII) in a wide pH range of 4.0-10.0. The redox cycle of BQ would produce semiquinone radicals, which could act as ligands to stabilize the formed Mn(III) in the system to promote the oxidation of BPA. Notably, the presence of BQ might promote the formation of MnO 2 . A novel mechanism was proposed that singlet oxygen ( 1 O 2 ), Mn(III)-ligands (Mn(III)-L) and in-situ formed MnO 2 were the main contributors to accelerate BPA degradation in the Mn(VII)/BQ system. Under acidic conditions, the in-situ formed MnO 2 involved in the redox reaction and part of the Mn(IV) was reduced to Mn(III), indicating that the electron transfer of BQ promoted the formation of active Mn species and enhanced the Mn(VII) oxidation performance. Semiquinone radicals generated by BQ transformation would couple with the hydrogen substitution products of BPA to inhibit BPA self-coupling and promote the ring-opening reactions of BPA. Mn(VII)/BQ had better effect in raw water than in pure water, indicating that the Mn(VII)/BQ system has high potential for practical application. This study provided insights into the role of DOM in enhancing the Mn(VII) oxidation in water treatment.
研究领域:
环境科学
·
水处理工程
·
化学工程
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产品关联
DOI
PubMed
高影响因子
ENVIRONMENTAL SCIENCE & TECHNOLOGY
·
2021
·
IF 9.028
Honglong Zhang,Zhenyu Shi,Ruopeng Bai,Dingxiang Wang,Fuyi Cui,Jing Zhang,Timothy J. Strathmann
Permanganate (Mn(VII)) has been widely applied as an oxidant in water treatment plants. However, compared with ozone, Fenton, and other advanced oxidation processes, the reaction rates of some trace organic contaminants (TrOCs) with Mn(VII) are relatively low. Therefore, further studies on the strategies for enhancing the oxidation of organic contaminants by Mn(VII) are valuable. In this work, 2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO), as an electron shuttle, enhanced Mn(VII) oxidation toward various TrOCs (i.e., bisphenol A (BPA), phenol, estrone, sulfisoxazole, etc.). TEMPO sped up the oxidative kinetics of BPA by Mn(VII) greatly, and this enhancement was observed at a wide pH range of 4.0–11.0. The exact mechanism of TEMPO in Mn(VII) oxidation was described briefly as follows: (i) TEMPO was oxidized by Mn(VII) to its oxoammonium cation (TEMPO+) by electron transfer, which was the reactive species responsible for the accelerated degradation of TrOCs and (ii) TEMPO+ could decompose TrOCs rapidly with itself back to TEMPO or TEMPOH (TEMPO hydroxylamine). To further illustrate the interaction between TEMPO and target TrOCs, we explored the transformation pathways of BPA in Mn(VII)/TEMPO oxidation. Compared to Mn(VII) alone, adding TEMPO into the Mn(VII) solution significantly suppressed BPA’s self-coupling and promoted hydroxylation, ring-opening, and decarboxylation. Moreover, the Mn(VII)/TEMPO system was promising for the abatement of TrOCs in real waters for humic acid, and ubiquitous cations/anions had no adverse or even beneficial impact on the Mn(VII)/TEMPO system.
研究领域:
环境科学
·
化学工程
✓ 已验证
DOI
PubMed
高影响因子
Journal of Environmental Chemical Engineering
·
2025
·
IF 7.2
Chen-Yan Hu,Xin-Yu Yang,Li-Li Hu,Hao Liu,Jia-Nan Chen,Ling-Mei Gao,Zheng-Yu Dong
The enhanced degradation mechanism of micropollutants by sulfite (S(IV)) activated permanganate (Mn(VII)/S(IV)) process under different pH conditions were investigated in this study. The Mn(VII)/S(IV) process can significantly promote the degradation of sulfamethoxazole (SMX), ibuprofen (IBU), iohexol (IOX) and acetochlor (ACE). Compared with the permanganate (Mn(VII)) process alone, the degradation efficiency of SMX, IBU, IOX, and ACE in the Mn(VII)/S(IV) process increased by 51.6 %, 38.9 %, 43 % and 78.7 %, respectively. The pH value has a significant impact on the degradation of the four target pollutants. The mechanism of the Mn(VII)/S(IV) process was further explored using SMX as a model pollutant. Hydroxyl radicals (HO•), sulfate radicals (SO 4 •− ), and reactive manganese species (RMnS, Mn(III), and Mn(V)) were detected in the process. HO• plays an important role in the degradation of SMX under acidic conditions. At pH= 7, RMnS is the main reactive species. Under alkaline conditions, SO 4 •− plays an important role in the process. Mn(III) and Mn(V) can also be converted into other manganese species. In addition, the possible degradation pathway of SMX was proposed. This work reveals the important role of pH in the generation and transformation of reactive species, and demonstrates the enormous potential of the Mn(VII)/S(IV) process in controlling micropollutants. Considering the complexity of water matrix, future studies can explore the application of the Mn(VII)/S(IV) process in practical water treatment.
研究领域:
环境科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF SOLID STATE CHEMISTRY
·
2023
·
IF 3.3
Chunming Huang,Wendong Zhao,Huifen Wang,Volodymyr Baran,Limin Han,Ning Zhu,Yijia Bai
The nitrogen lightly doped perovskite manganite La 0.5 Ba 0.5 MnO (3-δ)-x N x was synthesized following a mild nitridation strategy by optimizing annealing temperature, annealing time and NH 3 /Ar flow rate ratio. Neutron powder diffraction (NPD) characterization evidences an N-doping triggered structural phase transition from pseudo-cubic Pm -3 m to tetragonal P 4/ mmm and further confirms a preferable substitution at O1 and O2 sites closing to the Ba-rich layers. N 1s K-edge X-ray absorption near edge spectrum (XANES) with total fluorescence yield (TFY) mode, X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FT-IR) spectroscopy collectively convince the Mn–N bonded state. The O/N atomic ratio is determined to be 2.26/0.22 by XPS analysis closing to the value of 2.25/0.18 from NPD refinement. Magnetic property characterization reveals that both long-range Mn 3+ - O -Mn 4+ ferromagnetic coupling and high Curie temperature ( T C ) are maintained upon N-doping. Besides, significant spin frozen with robust domain pinning is identified below T C which can be ascribed to the short-range Mn–N–Mn clusters and/or oxygen defects. This work expands the connotation of transition-metal based perovskite oxynitride and may inspire the development of photosensitive semiconductor device with magnetic response.
研究领域:
材料科学
·
固体物理
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DOI
高影响因子
危险品化学品经营许可证（带存储）