CHEMOSPHERE
·
2022
·
IF 8.943
Yanzhuo Zhang,Mengqi Xu,Rui He,Jing Zhao,Wei Kang,Jinghua Lv
Because of the increasingly widespread contamination of antibiotics, the preparation of biochar by heteroatom doping to further improve the catalytic degradation efficiency of antibiotics has become a major focus of research. In this study, N-doped (NBC), S-doped (SBC), and NS-doped (NSBC) moso bamboo biochar were obtained at preparation temperatures of 300–700 °C. The concentration of environmentally persistent free radicals (EPFRs) in all biochars peaked when the preparation temperature was 500 °C: 2.45 × 10 19 spins·g −1 (BC), 9.23 × 10 19 spins·g −1 (NBC), 6.10 × 10 19 spins·g −1 (SBC), and 4.36 × 10 19 spins·g −1 (NSBC). After heteroatom doping, EPFR species were more abundant, and the distribution of three types of EPFRs (oxygen-centered (g > 2.0040), carbon-centered (g < 2.0030), and carbon-centered radicals with oxygen atom free radicals (2.0030 < g < 2.0040) varied with the preparation temperature. In the process of antibiotic degradation, both NBC and SBC increased the degradation rate of antibiotics, whereas NSBC reduced the degradation rate. Compared with the degradation rate of antibiotics of biochar (79.86%), the degradation rate of antibiotics by NBC, SBC, and NSBC via PMS activation was 92.23%, 88.86%, and 70.97% on average in 30 min, respectively. The greatest contributors to the catalytic degradation were SO 4 •- , followed by 1 O 2 , •OH, and O 2 •- . EPFRs and 1 O 2 might be the main contributors to the free radical and non-free radical pathways. The enhancement of EPFRs following the N doping or S doping of biochar is the key factor underlying PMS activation. Therefore, changes in the structure of biochar can better activate PMS to produce reactive oxygen species-degrading antibiotics. The mineralization rate of antibiotics by BC, NBC, SBC, and NSBC was 42.12%, 47.06%, 44.99%, and 39.01%, respectively. This means that a small portion of the antibiotics was completely decomposed into CO 2 , H 2 O, and inorganic substances after degradation. Cyclic experiments showed that heteroatom-doped biochar had higher reusability, and the degradation rate decreased less than 15%.
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高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2022
·
IF 9.136
Jixiang Xu,Yi Wang,Jun Wan,Lei Wang
In this work, carbon-doped CoMn 2 O 4 /Mn 3 O 4 (C-CoMnO) composite catalyst were prepared via calcining solvothermal product of Mn 2+ , Co 2+ , and 2-methylimidazole in air. The catalytic performance of activating peroxymonosulfate (PMS) for ciprofloxacin (CIP) degradation was discussed. The results showed that the 0.1 g L −1 C-2CoMnO could effectively activate PMS, resulting in 96.18% CIP was degraded within 60 min. The corresponding total organic carbon removal ratio and apparent rate constant were 81.33% and 0.043 min −1 , respectively. The influencing factors, such as Co/Mn molar ratios, calcination temperature, PMS concentration, solution pH, and coexisting ions were explored. The optimal catalytic system exhibited good recycling performance, wide pH adaptation and high resistance to salt interference. SO 4 ⋅ − , ⋅OH, and ⋅O 2 − -based radicals, as well as 1 O 2 and surface complexes-based nonradicals were participated in CIP degradation. The CIP degradation pathways were proposed. Density functional theory calculations (DFT) indicated that PMS was more easily activated via Co/Mn synergism. The doped carbon was also contributed to PMS activation via facilitating electron transfer. This study may shed light toward the synergistic effect of metal oxides in PMS activation.
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JOURNAL OF HAZARDOUS MATERIALS
·
2022
·
IF 14.224
Zelin Wu,Zhaokun Xiong,Rui Liu,Chuanshu He,Yang Liu,Zhicheng Pan,Gang Yao,Bo Lai
Metal leaching and catalytic stability are the key issues in Fenton-like reaction. Herein, a hollow yolk-shell nanoreactor (HYSCN) with shell confined Co species was fabricated for peroxymonosulfate (PMS) activation to degrade carbamazepine (CBZ). The uniform Co nanoparticles were completely anchored in a hollow void, further confined by a porous N-doped carbon shell. The unique construction significantly reduces Co species leaching in PMS activation and enhances catalytic stability. Co leaching came from HYSCN dropped by almost fourfold compared to CN-8 without shell confined (0.403 mg/L to 0.120 mg/L). The catalytic stability is also greatly improved, confirming the dominant role of heterogeneous catalysis in the HYSCN/PMS system. HYSCN exhibits excellent catalytic performance compared to a solid structure (SCSCN), demonstrating the significance of hollow structures. Mechanism study found that HO • , SO 4 • – and 1 O 2 induced in HYSCN/PMS system and the relative contributions were distinguished and quantified by stoichiometric methods. The UPLC-Q-TOF-MS/MS was used to identify the CBZ degraded intermediate products and the possible degradation pathway was proposed. This study will provide theoretical guidance for reducing metal leaching and improving catalytic stability in the PMS activation.
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2022
·
IF 9.136
Yi Han,Mingjie Huang,Wei Xiang,Chen Wang,Yongjie Li,Xiaohui Wu,Juan Mao,Tao Zhou,Hong Li,Deming Wu
Fe-based metal–organic frameworks (MOFs) are popular in activating oxidants e.g·H 2 O 2 and persulfate (PS) for degrading recalcitrant organic substances, generally regarded with a simple interfacial efficient iron cycle. This study has revealed that a novel two-steps single-electron transfer mechanism would occur initially to activate the rapid degradation 4-chlorophenol (4-CP) in the MIL-88B(Fe)/H 2 O 2 system (88B/H 2 O 2 system). The degradation of 4-CP was acidic favorable (pH 0 ≤ 6.0) and could be divided into two reaction stages, i.e., initial lag phase (0–10 min) and following rapid decay phase (10–50 min). In the first stage, H 2 O 2 was slowly activated on the surface of 88B to form superoxide radical (O 2 •– ), which would lead to the accumulation of the key intermediate hydroquinone (HQ) through reducing 4-CP. Afterwards, HQ could reductively dissolve iron ions which would lead to the subsequent efficient homogeneous Fenton reaction for the rapid oxidation of 4-CP by hydroxyl radical (•OH) in the following rapid decay phase. It was interesting to note that specific aromatic compounds, which would form reductive benzenediols intermediates by O 2 •– , could be efficiently degraded in the 88B/H 2 O 2 system. The result of this study is expected to provide a new insight for understanding the catalytic oxidation process based on MOFs, and its application if possible.
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CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Jiaxin Zhu,Zekun Liu,Yihua Chen,Zhiqiang Chen,Hang Ma,Jian Sun,Liao Meng,Tongzhou Liu
The discharge of widely used fluorinated aromatics (FAs) leads to their notoriously high persistence and toxicity in natural environments. Defluorination is the key step for FAs pollutants detoxification. Due to its easy operation and mild reaction conditions, hydrodefluorination (HDF), especially electrochemical HDF, is a promising approach for FAs detoxification. A comprehensive and detailed investigation of the effective cathode and mechanism insights are contributable for the development of effective FAs defluorination techniques. In this study, 4-fluorophenol (4-FP) was selected as a model compound to optimize the electrochemical HDF process and understand the reaction mechanism. Cathode coating material investigation revealed that Rh outperformed Pd due to its higher reactivity towards C F bond cleavage. The Rh coating was primarily elemental and in Rh(1 1 1) crystalline form which helped store the generated atomic hydrogen (H*). Reaction conditions optimizations showed 4-FP degradation favored acidic > alkaline > neutral environment and a cell potential higher than −3 V was required for efficient 4-FP degradation. Dissolved oxygen (DO) negatively affected 4-FP degradation and the rapid 4-FP decay only occurred after DO depleted in the solution. Based on quenching experiments and ESR analysis, H* was determined as the main reactive species. In situ Raman characterization suggested that electrochemical 4-FP degradation was initiated by 4-FP adsorption through R···F···Rh bridging and H* generation/adsorption on Rh coated cathode, resulting in phenol generation. The generated phenol further experienced hydrogenation to yield cyclohexanone and cyclohexanol with lower toxicity and better biodegradation potential, demonstrating that electrochemical treatment of 4-FP simultaneously achieved defluorination along with detoxification. The outcomes of this work provide support for electrocatalyst technology development towards efficient FAs treatment while providing in-depth observation of the electrochemical HDF process.
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2023
·
IF 8.6
Yangke Long,Shixin Huang,Shiyin Zhao,Guicong Xiao,Jianlin Sun,Dan Peng
The practical application of periodate-based advanced oxidation technologies (PI-AOTs) for wastewater treatment requires efficient and cost-effective activators. Pyrolyzed Fe–N/C materials are potential candidates, however, their actual active sites and activation mechanisms are yet to be fully understood. Herein, a series of Fe–N/C samples (denoted as Fe@NC- X ) with differing structures and iron components were delicately synthesized. Experimental studies on the structure–activity relationship and density functional theory (DFT) computations revealed that Fe–N x species serve as the dominant active site for periodate activation, while the inactive iron-based particles (i.e., Fe 0 and Fe 3 C) optimized the binding affinity of surrounding carbon layers with periodate, resulting in enhanced activity. In-depth exploration of the oxidative mechanism revealed that Fe@NC- X activated periodate through an electron transfer regime. Our results also showed that the optimal Fe@NC-0.2/periodate system was highly effective in catalyzing the oxidation of 4-CP, outperforming many reported activators. These findings provide an indispensable foundation for the rational development of advanced Fe–N/C activators and offer vital insights into the mechanism underlying pollutant destruction through PI-AOTs.
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2023
·
IF 8.6
Mengxin Wang,Yijie Sun,Chao Huang,Ping Wang,Hao Cheng,Chengyou Sun,Danni Jiang,Dingxun Ling,Ke Ouyang,Chonglin Feng
The limited mass transfer of short-lived radical species is an inherent drawback of heterogeneous oxidation processes. Herein, we fabricated zeolitic imidazolate framework (ZIF)-67 loaded nanoreactors with precise pore sizes based on anodic alumina oxide (AAO) templates to achieve nanoscale spatial confinement for enhanced radicals-mediated oxidation reactions. The prepared ZIF-67@AAO membrane/peroxymonosulfate (PMS) system exhibits perfect catalytic performance with a rhodamine B (RhB) removal of 100 % within 60 s under an AAO pore size of < 20 nm. The reaction rate constant of RhB degradation by the ZIF-67@AAO <20 nm /PMS system was 2.52 and 893 times that by the ZIF-67@AAO 200–300 nm /PMS and ZIF-67/PMS system (no confinement), respectively. The ordered mesoporous structure of the ZIF-67@AAO nanoreactors provided many channels for PMS and RhB molecules to enter the confined inner space of the catalyst, leading to a significant improvement in catalytic performance under nanoconfinement. Radical quenching and electron paramagnetic resonance (EPR) results indicated that SO 4 − , ·OH, 1 O 2 , and O 2 − were generated in the ZIF-67@AAO/PMS system, and their amounts were affected by spatial confinement and achieved the maximum at a pore size of < 20 nm. Furthermore, the ZIF-67@AAO catalytic membrane exhibited attractive long-term operation stability with perfect activity and neglectable Co leaching. The results of this study provide an important reference for designing novel catalytic membranes for water decontamination.
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CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Aihua Xu,Runshi Chen,Wenpei Zhao,Jiajin Lin,Rongrong Hu,Aimal Khan,Wei Li,Xiaoxia Li,Shuaiqi Zhao,Yongcai Qiu
Modifying the surface structure of catalysts is critical for facilitating peroxymonosulfate (PMS) activation. Here, we present a quenching approach to effectively modify the surface chemistry of LaMnO 3 nanocatalysts, in which the optimal catalyst obtained by quenching displays higher catalytic degradation performance for levofloxacin (LEVO). The experimental results demonstrates that the increased intrinsic catalytic activity is directly connected to the quenching-induced exposed facets transition and synergistic effect of Cu/Co ions. Meanwhile, density functional theory calculations (DFT) further reveal the aforementioned modifications to surface structure result in an upward shift of d-band centre, which optimizes the adsorption of PMS and makes it easier for the transfer of electron between Mn sites and PMS, thereby facilitating the reduction of Mn 4+ and enhancing catalytic activity for PMS activation and LEVO degradation. This study presents new ideas for controlling surface structure of perovskite metal oxide catalysts and broadens applicability of quenching chemistry in heterogeneous catalysis.
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CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Yarui Wang,Chengzhuo Yu,Sen Wang,Jin Xu,Fanglan Geng,Silong Wang,Jitao Lv,Lixia Zhao,Yawei Wang
Humic acids (HA) released during algal bloom poses a key challenge for efficient photocatalytic degradation of Microcystin-LR (MC-LR) due to their scavenging function on active species. Herein, MIL-101(Fe)/TiO 2 -P25 (M/P) was constructed to diminish the inhibitory effect of HA on the photocatalytic degradation of MC-LR. Results showed that MC-LR could be efficiently removed assigning to the photogenerated holes (h + ) and superoxide radical (O 2 •− ) oxidation under visible light irradiation, where the carboxy groups of D -glutamic acid (Glu) and methyl- D -aspartic acid (MeAsp), and Adda side chain related to MC-LR biotoxicity were selectively destroyed to achieve MC-LR detoxication. More importantly, HA exerted non-inhibitory effect on MC-LR removal by M/P. The counteracting mechanisms were studied. Firstly, the location of TiO 2 in the pore structure of MIL-101(Fe) could occupy the adsorption sites of HA, and decrease the HA adsorption on M/P. Furthermore, XPS analyses suggested the coordination of unsaturated Fe metal sites on the surface of M/P hybrids complexed with –OH and –COOH of HA, which could accelerate the electron transfer and reduce hole consumption. Thus, the inhibitory effect of HA was alleviated during photocatalytic MC-LR treatment. This work offers a possible way to remove MC-LR in an abundant HA matrix water system efficiently.
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FUEL
·
2023
·
IF 7.4
Yanjie Niu,Jie Xu,Liqing Chen,Sixi Guo,Fanhui Guo,Yixin Zhang,Jianjun Wu
As a typical coal-based solid waste, coal gasification fine slag (GFS) will have an annual discharge of more than 50 million tons in 2025 in China alone. However, the difficulty of its resource utilization lies in the precise separation of carbon and ash due to their complex distribution pattern. There is an urgent need to develop GFS-based materials for comprehensive utilization of carbon and ash. In this study, a combined process of acid leaching and pyrolysis was designed, in which active metal iron was leached from ash and immobilized on the surface of residual carbon in the form of Fe-N-C. The unique structure of Fe-N doped carbon/ash synergistically improved the efficiency of electrocatalytic degradation of organic wastewater by 72.78 ± 1.37%. The hierarchical porous structure of residual carbon considerably enhanced the accessibility of ash catalytic sites. Abundant ash defects and Fe-N active sites promoted the conversion of free radical precursors to reactive oxygen species (ROS). The removal rate of various organic wastewater within 35 min reached more than 100 ± 1.83% %, with excellent electrocatalytic performance and pH adaptability. Fe-NCPE had a high specific surface area (318.36 m 2 ·g −1 ), orderly graphite phase (002 crystal surface size 1.3 nm), and abundant catalytic sites. We also proposed the catalytic mechanism by combining molecular simulation with experiments. The high adsorption capacity above 24.07 ± 0.12 mg·g −1 ensured the continuous and rapid supply of pollutants and H 2 O 2 near the catalytic site·H 2 O 2 was converted into ROS mainly composed of hydroxyl groups through the valence state change of aluminum or Fenton-like reaction of nitrogen-linked iron. The ROS then attacked organic molecules to degrade pollutants. The above two processes corresponded to two cyclic catalytic reactions. Therefore, this study provides an innovative and promising approach for comprehensive utilization of carbon and ash in GFS.
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Journal of Environmental Sciences
·
2023
·
IF 6.9
Jingjing Cui,Xiangyu Liu,Feifan Qie,Chengzhe Xie,Qingdong He,Jian Liu,Steven L. Suib,Wenbo Wang
Reasonably designing highly active, environmentally friendly, and cost-effective catalysts for efficient elimination of pollutants from water is desirable but challenging. Herein, an efficient heterogeneous photo-Fenton catalyst tourmaline (TM)/tungsten oxide (WO 3-x ) (named TW10) containing tungsten/boron/iron (W/B/Fe) synergistic active centers and 90% of cheap natural tourmaline (TM) mineral rich in Fe and B elements. The TW10 catalyst can quickly activate peroxymonosulfate (PMS) to generate massive active free radicals, which may induce the rapid and efficient degradation of tetracycline (TC). The TW10/PMS/Visible light system can effectively degrade up to 98.7% of tetracycline (TC) in actual waters (i.e. seawater, Yellow River, and Yangtze River water), and the catalytic degradation rates reach 1.65, 5.569, and 2.38 times higher than those of TM, WO 3-x , and commercial P25 (Degussa, Germany), respectively. In addition, the catalyst can be recycled and reused multiple times. Electron spin resonance spectroscopy (EPR), X-ray photoelectron spectroscopy (XPS), and liquid chromatograph-mass spectrometer (LC-MS) analyses confirm that the synergistic catalytic effect of W/B/Fe sites on the TW10 catalyst accelerates the electron transfer between Fe(II) and Fe(III), as well as between W(V) and W(VI), and thus promotes the rapid degradation of TC. The catalytic reaction mechanism and degradation pathway of TC were explored. This work provides a feasible route for the design and development of new eco-friendly and efficient catalyst.
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JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY
·
2023
·Vol. 98
·期 10
·2597-2609
·
IF 3.4
Jun Chen,Xiaohong Yang,Shangqing Xia,Xue Li,Yutong Wang,Zongsheng Zhan,Mingxia Du,Dongliang Shao
BACKGROUND Persulfate (PS) has the capability to yield free radicals via activators, thereby shaping an advanced oxidation process that can significantly contribute to effective sterilization. Central to this technology is the pursuit of appropriate activators. RESULTS In our research, we successfully synthesized an economical and efficient PS activator, namely a pyrrhotite-loaded sludge carbon (Pyr-SC) composite. This was achieved via a straightforward procedure utilizing two environmentally friendly and cost-efficient raw materials: pyrite and sludge. Pyr-SC exhibited a specific surface area of 60.4 m 2 g −1 and rich functional groups such as carbon–sulfur and sulfur–oxygen. The magnetic and graphitic carbon structures were formed at high temperatures during the preparation process, and the sludge carbon (SC) exhibited porous defects, which allowed the effective insertion of iron/sulfur into SC to form the stable Pyr-SC structure. Pyr-SC activated PS, which further sterilized Escherichia coli in the wastewater at a sterilization rate of 7.00 lg E. coli at 10 7 cfu mL −1 in 80 min. The sterilization rate was less affected by temperature and pH. We verified sulfate, hydroxyl and oxygen free radicals produced by the Pyr-SC-activated PS. The Pyr-SC composite, thanks to its expedited electron transfer, could activate PS to engender free radicals. Furthermore, the oscillatory transformation of iron ions caused by the monosulfide ion on the Pyr-SC surface augmented the production of free radicals. An assessment of Pyr-SC's stability was conducted, adhering to the principles of magnetic separation. After five cycles in the Pyr-SC/PS reaction system, the sterilization rate reached 3.29 lg, whereas the leaching rate of iron in Pyr-SC decreased. The Pyr-SC/PS reaction system also had a broad spectrum of wastewater. CONCLUSION The economically prepared Pyr-SC composite provided an effective technology for activating PS and sterilizing microorganisms in wastewater. © 2023 Society of Chemical Industry.
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