ENVIRONMENTAL SCIENCE & TECHNOLOGY
·
2022
·
IF 11.357
Honglong Zhang,Zhenyu Shi,Jun Ma,Fuyi Cui,Jing Zhang,Timothy J. Strathmann
In this study, a representative redox mediator, 2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO), and its para-substituted derivatives (TEMPOs: 4-hydroxyl-TEMPO, 4-acetylamino-TEMPO, and 4-amino-TEMPO) significantly accelerated the abatement of trace organic contaminants (TrOCs, i.e., bisphenol-A (BPA), phenol, amines, and phenylbutazone) by Mn(VII) over a wide pH range of 4.0–9.0. The addition of substituents at para to the > N–O• moiety significantly influenced the degradation kinetics of TrOCs by changing the reduction potentials of TEMPOs and the corresponding oxoammonium cations (TEMPOs+); a linear relationship was observed between the substituents’ para Hammett sigma constants and the reduction potentials of TEMPOs and TEMPOs+. Pseudo-first-order reaction rate constants (kobs, min–1) of TrOC degradation by Mn(VII)/TEMPOs were also affected by the pKa of the TrOCs. Generally, the highest kobs values for individual TrOCs were observed at pH near the pKa even for TEMPOs+ with relatively pH-invariant reduction potentials. Overall, TrOC abatement kinetics were related to a combination of reactive species (Mn(VII), in situ formed MnO2, and TEMPOs+). For BPA, the relative contributions (R) of reactive species ranked as R(TEMPOs+) > R(Mn(VII)) > R(in situ formed MnO2) at pH 4.0–8.0, whereas R(Mn(VII)) > R(TEMPOs+) at pH 9.0 mainly owing to a change in BPA speciation as the pH approached the pKa1 value for BPA. The results of this study are useful for the development of heterogeneous TEMPO-based redox mediators and future applications of TEMPO-mediated oxidation systems for accelerated abatement of TrOCs in water.
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高影响因子
WATER ENVIRONMENT RESEARCH
·
2022
·Vol. 94
·期 4
·e10714
·
IF 3.306
Yao Shi,Yifei Xing,Zhilian Song,Xueming Dang,Huimin Zhao
Fe–Mn binary oxide (FMBO) is a promising adsorbent for As(III) removal through combined adsorption and oxidation. The calcined oyster shell-supported Fe–Mn binary oxide (FMBO/OS) adsorbent was synthesized by the co-precipitation method. Results indicated that the calcined oyster shell, as a carrier, improved the stability of FMBO and its adsorption capacity for As(III). The maximum adsorption capacity of FMBO/OS on As(III) reached 140.5 mg·g −1 . Under pH 5.0 and 25°C, the removal efficiency of FMBO/OS to As(III) solution (C 0 = 10 mg·L −1 ) reached 87% within 12 h. Moreover, based on the characterization analyses, the removal mechanisms of As(III) were deduced to include the combined adsorption and oxidation process of FMBO and the synergistic effect of oyster shells. This work provides new insights into synthesizing efficient and green adsorbents to remove aqueous As(III). Meanwhile, it provides technical support for reusing waste biomass materials such as the oyster shell. Practitioner Points FMBO/OS was prepared by a simple hydrothermal co-precipitation method. The carrier alleviates the agglomeration of Fe–Mn oxides. The adsorbent shows a strong adsorption capacity of As(III) and good selectivity. The good results benefit from the synergistic effect of calcium arsenate generation. The prepared adsorbent can adsorb arsenic in real samples.
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高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2022
·
IF 16.744
Guifang Wang,Guangchuan Liang,Huizhen Xiao,Jun Qiu,Haiyan Liu,Shaojian Ma,Sridhar Komarneni
The conventional environmental remediation materials, which are applied for the long-term treatment of mine tailings are easy to fail when affected by acid rain. Therefore, dynamic column simulation experiments were conducted to compare the immobilization persistence of As, Mn, Pb and Zn by the addition of triethylenetetramine modified montmorillonite (TTA-Mt) and calcium-based montmorillonite (Ca-Mt) in sulfide tailings during a simulated 5-year study of acid rain leaching. The structural and morphological characteristics of TTA-Mt were analyzed with FTIR, XRD, SEM, TEM and EDS. Results showed that the additions of TTA-Mt could persistently immobilize the heavy metal ions while Ca-Mt additions had little effect. After long-term simulated leaching for 5 years, TTA-Mt still had superior environmental stability for Zn and As with the immobilization rates of 96% and 86%, and the leaching amounts of Mn and Pb were less than 4.23 and 0.66 mg/kg, respectively. Morphology and chemical fraction analyses confirmed that the immobilization was mainly due to the formation of relatively stable phases by complexation and precipitation. Results presented here demonstrated the significant potential of TTA-Mt for long-term immobilization of heavy metals in tailings against acid rain and thus could provide guidance for remediation of tailings.
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高影响因子
CRYSTENGCOMM
·
2023
·Vol. 25
·期 20
·3066-3078
·
IF 3.1
Jinyu Ma,Qing Sun,Chuan Jing,Faling Ling,Xiao Tang,Yanhong Li,Yongjie Wang,Sha Jiang,Kexin Yao,Xianju Zhou
Since the energy density and voltage window of supercapacitors cannot match that of lithium-ion batteries, supercapacitors are far from replacing batteries but can only be seen as a supplement to battery charge storage or transmission devices. The design of transition metal oxide-based electrodes with high cycling capacitance retention is very important for the development of supercapacitors. In this study, flower-like SAC@NiCoMn-LDH electrode materials with different Mn doping ratios were prepared by a hydrothermal method with mesoporous carbon (SAC) as the substrate. Density functional theory (DFT) calculations confirm that Mn doping can enhance the adsorption of OH− and the desorption of the H proton. In addition, Mn doping increases the density of states of LDH near the Fermi level and increases the number of active electrons, which is conducive to the occurrence of electrochemical reactions. In the three-electrode system, SAC@Ni2Co0.95Mn0.05-LDH with optimal doping ratio increased the specific capacitance by three times compared to that of NiCo-LDH and displayed an excellent cycling stability (83.76% capacitance retention after 50 000 cycles). Moreover, the prepared SAC@Ni2Co0.95Mn0.05-LDH and commercial activated carbon (AC) were made into electrode plates and then assembled into a SAC@Ni2Co0.95Mn0.05-LDH//AC asymmetric supercapacitor (ASC). The ASC exhibited high energy density (23.68 W h kg−1 at 325 W kg−1) and excellent specific capacitance retention (85.32% after 50 000 cycles), making it well suited for efficient wind energy storage and conversion with promising practical applications.
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高影响因子
CHEMOSPHERE
·
2023
·
IF 8.8
Linsong Cheng,Yuanxiang Mao,Lei Jiang,Rui Ma,Jiangsen Ma,Yiyuan Zhuo,Qiushi Shen,Caocong Liu,Liuwei Zhao,Xiaoyi Xu,Fangying Ji
The high concentration of salt in organic wastewater has a strong inhibitory effect on the removal of pollutants. A method for the efficient removal of trace pollutants in high-salinity organic wastewater was developed. This study investigated the effect of the combination of permanganate [Mn(VII)] and calcium sulfite [S(IV)] on pollutant removal in hypersaline wastewater . The Mn(VII)-CaSO 3 system removed more pollutants from high-salinity organic wastewater than from normal-salinity wastewater. Chloride (increasing from 1 M to 5 M) and low concentration of sulfate (increasing from 0.05 M to 0.5 M) significantly enhanced the system's resistance to pollutants under neutral conditions. Despite the fact that Cl − can combine with the free radicals in the system and reduce their efficiency in removing pollutants, the presence of chloride ions greatly enhances the electron transfer rate in the system, promoting the conversion of Mn(VII) to Mn(III) and significantly increasing the reaction rate of Mn(III) as the primary active species. Therefore, chloride salts can greatly enhance the removal of organic pollutants by Mn(VII)-CaSO 3 . Although sulfate does not react with free radicals, a high concentration of sulfate (1 M) will affect the formation of Mn(III), which greatly weakens the removal effect of the entire system on pollutants. The system can still have a good pollutant removal effect with mixed salt. Altogether, this study demonstrates that the Mn(VII)-CaSO 3 system offers new possibilities for the treatment of organic pollutants in hypersaline wastewater.
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高影响因子
WATER RESEARCH
·
2023
·
IF 12.8
Yinning He,Jiayi Li,Jingyu Tang,Haijun Cheng,Tao Zeng,Zhiqiao He,Da Wang,Lizhang Wang,Shuang Song,Jun Ma
In this study, N-doped Mn 3 O 4 catalysts (Mn- n N) with electron-dense Mn sites were synthesized and employed in heterogeneous catalytic ozonation (HCO). These catalysts demonstrated excellent performance in pyrazines degradation and odor elimination. The synthesis of Mn- n N was achieved through a facile urea-assisted heat treatment method. Experimental characterization and theoretical analyses revealed that the Mn N structures in Mn- n N, played a crucial role in facilitating the formation of electron-dense Mn sites that served as the primary active sites for ozone activation. In particular, Mn-1N exhibited excellent performance in the HCO system, demonstrating the highest 2,5-dimethylpyrazine (2,5-DMP) degradation efficiency. • OH was confirmed as the primary reactive oxygen species involved in the HCO process. The second-order rate constants for 2,5-DMP degradation with O 3 and • OH, were determined to be (3.75 ± 0.018) × 10 −1 and (6.29 ± 0.844) × 10 9 M −1 s −1 , respectively. Seventeen intermediates were identified through GC-MS analysis during the degradation of 2,5-DMP via HCO process with Mn-1N. The degradation pathways were subsequently proposed by considering these identified intermediates. This study introduces a novel approach to synthesize N-doped Mn 3 O 4 catalysts and demonstrates their efficacy in HCO for the degradation of pyrazines and the elimination of associated odors. The results show that the catalysts are promising for addressing odor-related environmental issues and provide valuable insights about the broader significance of catalytic ozonation processes.
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高影响因子
CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Yong He,Xiao Kang,Hui-wen Xiong,Lei Zhang
Spinel composite is being considered for electrode materials in molten salt electrolysis, aiming to improve high-temperature stability and conductivity. Multi-phase composites with the general formula of (Fe 1-3 x - y Ni y Co x Cr x Mn x ) 3 O 4 ( x = 0.03, 0.06, 0.09, y = [1-2 x ]/3) were prepared via in situ SPS method. The composites were confirmed to consist of spinel and rock-salt phases through XRD and SEM analysis. Compared to the Ni–Fe–O system, the doping of Cr, Mn and Co improved the phase stability of the spinel during SPS, but hindered the shrinkage process. These composite exhibited low thermal diffusivity (1.236–2.481 m 2 /s, room temperature) and low coefficient of thermal expansion (9.8 - 14.4 × 10 −6 K −1 , 400–800 °C). Moreover, the composite with x = 0.06 and y = 0.29 exhibit 94.4 % lower permittivity, 7 times higher dielectric loss (at 40 Hz) and 26.6 % lower high-temperature conductivity (at 800 °C) than that of Ni–Fe–O system. This work demonstrates the enhanced thermal and electrical properties of spinel-based composites, which can provide inspiration to researchers and promote the development of high-temperature electrodes.
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高影响因子
Journal of Water Process Engineering
·
2023
·
IF 7
Jinbing Huang,Xiaoyan Liu,Shiwei Xie
Although electrochemical activation of permanganate ( E -PM) is a green and efficient method to degrade refractory organics by in-situ generated reactive Mn( III ) aq , this process highlights on the presence of promoter and/or stabilizer. Oxalate (OA) is a widespread organic chelate in natural water bodies (with concentrations up to 1 mM), but whose effect on the E -PM process is still unclear. In this study, we found electrolysis and the presence of OA both promote the activation of PM for the degradation of diclofenac (DCF), showing a high synergistic coefficient (3.23) and elevated reaction constant (0.1395 min −1 ). Nevertheless, this process is highly pH-dependent, behaving decreased reactivity as pH value increasing from 3 to 11. Sufficient concentration of OA (≥0.5 mM in this study) is required for stabilizing Mn(III). UV–vis spectra, visual evidence and quenching experiments identified the presence and dominant role of Mn(III)-OA on the degradation of DCF. Using chronoamperometry, we confirmed Mn(III)-OA was primarily generated from the electro-reduction of PM in the presence of OA at pH 5.
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高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2023
·
IF 8.6
Dongmei Liu,Aiying Guo,Yanling Qi,Zhixin Ji,Hongjuan Li,Xiumei Cao,Zhiwei Zhang,Xinyue Zhang,Kunze Wu,Aijun Cai
Removal of antibiotics and bacteria from wastewater is an effective approach to test the efficacy of catalyst and thus address the issues of water contamination. In this study, a stable magnetic Mg/Mn–layered double oxide–doped biochar composite (MgMnLDO–MBC) was prepared using Lentinula edodes substrate. This composite could further effectively activate the persulfates (PS), such as peroxymonosulfate (PMS) and peroxydisulfate (PDS). MgMnLDO coupling endowed BC and magnetic biochar (MBC) with enhanced surface areas, adsorption sites, and free radicals, which facilitated the improvement of catalytic activity of MgMnLDO–MBC/PS system toward pollutants. MgMnLDO-MBC/PMS system could remove 90.8% of ciprofloxacin (CIP) with 2.8 times the removal efficiency of MBC/PMS system. Density functional theory (DFT) calculation and intermediate analysis showed that the synergistic effect of nucleophilic, electrophilic, and radical active species–mediated reactions improved the removal performance of MgMnLDO–MBC/PMS system. MgMnLDO–MBC/PDS system could efficiently kill 97.6% Escherichia coli and 99.7% Staphylococcus aureus , and destroy the existing biofilms. The effects of composite concentration, PMS loading, pH, temperature, common anions, and humic acid on removal efficiency were also evaluated. After five consecutive cycles, MgMnLDO–MBC/PS system still exhibited high catalytic performance toward CIP removal and bactericidal ability. Results of quenching and electron spin resonance (ESR) showed that ·SO, ·OH, 1 O 2 , and charge transfer were together involved in CIP removal, with ·SO playing a major role. Furthermore, the double–layered metal oxide (LDO) and MBC present in MgMnLDO–MBC composites exhibited a strong synergistic effect in the catalytic process, which resulted in higher reactivity and lower leaching rate of metal ions. In this study, an environment–friendly catalyst was prepared using industrial waste and its efficiency for removal of antibiotics and bacteria from wastewater was verified.
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高影响因子
Journal of Environmental Chemical Engineering
·
2023
·
IF 7.7
Junyong He,Ya Yang,Peidong Hong,Yulian Li,Chao Xie,Zijian Wu,Minqiang Li,Lingtao Kong
The use of peroxymonosulfate (PMS) activation to eliminate organic contaminants is a promising technology to purify water owing to its strong reactivity. However, because of the existed rate limiting step, the performance of PMS activation was restrained and required external energy consumption. Therefore, a new strategy was proposed to solve this problem by preparing catalysts with abundant electron-rich sites and electron traps to accelerate PMS activation. In this research, a novel MnCeO x -H catalyst with rich surface oxygen vacancies was firstly synthesized to accelerate the transfer of electrons among the catalysts, oxidant and pollutants. The contaminants were rapidly eliminated in the MnCeO x -H/PMS system, while the reaction rate constant of MnCeO x -H/PMS system was 30 times higher than that of CeO 2 /PMS system. The surface oxygen vacancies were able to adsorb and trap PMS, then the free electrons of oxygen vacancies would reduce PMS and produced HO•, 1 O 2 and SO 4 •- , while 1 O 2 played a major role. The contaminants which acted as electron-donors in this system were adsorbed at Mn, Ce sites, achieving effective conversion recycling of Ce(IV)/Ce(III), Mn(III)/Mn(II) and Mn(IV)/Mn(III). This discovery is believed to inaugurate a novel way for designing powerful electron-rich sites and electron traps to accelerate PMS activation for contaminants degradation.
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高影响因子
JOURNAL OF LUMINESCENCE
·
2023
·
IF 3.6
Xiaochun Hou,Chengxue Du,Qing Pang,Chaoyang Jia,Xiaojun Wang,Dangli Gao
Up-conversion persistent luminescence (UCPL) nanoparticles have captured tremendous attention due to their unique optical operating performance such as the absence of auto-fluorescence and the charging capacity of near-infrared (NIR) light. However, the weak afterglow intensity as well as low duration limits their practical applications including multimode anti-counterfeiting and biological imaging, etc. Herein, typical green persistent luminescence (PersL) and photo-stimulated luminescence (PSL) of Zn 2 GeO 4 :Mn 2+ phosphors were enhanced via non-equivalent Li + co-doping, in which the preferred site selection of Mn 2+ and Li + have been verified by using the first-principles theory. The possible luminescent enhancement mechanisms were proposed based on improving the oxygen vacancy density and promoting the formation of Mn 4+ defect energy level in bandgap structure by non-equivalent doping of Li + . Interestingly, UCPL of Zn 2 GeO 4 :Mn 2+ ,Li + can be achieved after charging of Vis to NIR light. It is worth noting that this UCPL can be further enhanced by the sensitization of NaYF 4 :Yb,Tm nanoparticles via simply mixing Zn 2 GeO 4 :Mn 2+ ,Li + and NaYF 4 :Yb,Tm under 980 laser stimulation. As a result, Zn 2 GeO 4 :Mn 2+ ,Li + phosphor exhibits the enhanced quintuple-mode luminescence including photoluminescence , PersL, PSL, photo-stimulated persistent luminescence and UCPL. In particular, the achieved NIR rechargeable UCPL hybrid phosphors exhibit enormous potential for higher order anti-counterfeiting and rewriteable data encryption and decryption applications.
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高影响因子
IONICS
·
2021
·Vol. 27
·期 8
·3553-3566
·
IF 2.817
Zhang Boyuan,Song Senyang,Li Wenyue,Zheng Lewen,Ma Xiaoyan
Design and construction of multiphase nanostructures of metal organic frameworks (MOF) has recently been considered an effective method for the preparation of synergistic and excellent performance supercapacitor materials. Herein, Ni-Co-Mn-based metal organic frameworks (Ni-Co-Mn MOF) are prepared through an effortless one-step hydrothermal method, in which multiple metal nodes were evenly distributed between MOF nanostructure through ligands and formed a multiphase nanostructure through synergy. The synthesized Ni-Co-Mn 0.25 MOF exhibits a prominent specific capacitance of 1575 F g −1 at 1 A g −1 , remarkable rate capability and cycling stability. Moreover, we constructed an asymmetrical supercapacitor, which performed an excellent energy density of 73.56 Wh kg −1 at a power density of 399 W kg −1 and great cycling stability with 81.64% of original capacitance after 5000 cycles. Ni-Co-Mn MOF is a promising hybrid electrode material for excellent performance supercapacitor as well as it provides a simple and economic way to fabricate supercapacitor composite materials.
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