作者机构：
[Li, Zhi; Zhu, Mingshan; Zhou, Daixi] Jinan Univ, Sch Environm, Guangdong Key Lab Environm Pollut & Hlth, Guangzhou 511443, Peoples R China.;[Hu, Xinjiang] Cent South Univ Forestry & Technol, Coll Environm Sci & Engn, Changsha 410004, Peoples R China.;[Chen, Li] Chinese Peoples Liberat Army Gen Hosp, Med Ctr 1, Dept Gen Practice, Beijing 100853, Peoples R China.
通讯机构：
[Chen, L ] C;[Zhu, MS ] J;Jinan Univ, Sch Environm, Guangdong Key Lab Environm Pollut & Hlth, Guangzhou 511443, Peoples R China.;Chinese Peoples Liberat Army Gen Hosp, Med Ctr 1, Dept Gen Practice, Beijing 100853, Peoples R China.
关键词：
advanced oxidation process;persulfate;reactive oxygen species;single atom catalysts;substance
摘要：
In this review, SACs with different metal species and substrates are summarized to investigate the metal−support interaction effects on the persulfate oxidation reaction for water treatments. Abstract With maximum utilization of active metal sites, more and more researchers have reported using single atom catalysts (SACs) to activate persulfate (PS) for organic pollutants removal. In SACs, single metal atoms (Fe, Co, Cu, Mn, etc.) and different substrates (porous carbon, biochar, graphene oxide, carbon nitride, MOF, MoS2, and others) are the basic structural. Metal single atoms, substances, and connected chemical bonds all have a great influence on the electronic structures that directly affect the activation process of PS and degradation efficiency to organic pollutants. However, there are few relevant reviews about the interaction between metal single atoms and substances during PS activation process. In this review, the SACs with different metal species and substrates are summarized to investigate the metal−support interaction and evaluate their effects on PS oxidation reaction process. Furthermore, how metal atoms and substrates affect the reactive species and degradation pathways are also discussed. Finally, the challenges and prospects of SACs in PS‐AOPs are proposed.
摘要：
Metal-based materials are widely regarded as promising catalysts for activating peroxymonosulfate (PMS) to remove refractory organic contaminants with high efficiency. In our study, Ni-Fe layered double hydroxide (LDH)-biochar (BC) composite-induced PMS-based advanced oxidation process (AOP) was utilized to elucidate the degradation of tetracycline hydrochloride (TCH). In Ni-Fe LDH-BC/PMS system, more than 99% TCH (45 mu M) could be removed effectively at low doses of oxidant (PMS, 0.10 mM) and catalyst (Ni-Fe LDH-BC, 0.10 g/L) addition within 80 min. Besides, the Ni-Fe LDH-BC/PMS system showed high resistance to some inorganic anions, and the Ni-Fe LDH-BC composite possessed excellent reusability in the degradation of TCH (>99% in four cyclic experiments). The reaction mechanisms were investigated via electron paramagnetic resonance detection, chemical quenching tests, probe experiments, and electrochemical measurements. These results indicated that the electron-shuttle mechanism played the dominant role in the removal of TCH. It is worth noting that determination of PMS concentration can reflect the reliability of quenching experiments. In the Ni-Fe LDH-BC composite, BC could not only improve the dispersion of Ni-Fe LDH, but also increase the conductivity of Ni-Fe LDH. Overall, a successful modification strategy was proposed in our study to improve the catalytic property of Ni-Fe LDH, and reaction mechanisms of TCH degradation were discussed deeply and comprehensively.
关键词：
MOFs;Arsenic;Peroxymonosulfate;Adsorption and catalysis;DFT
摘要：
The removal of arsenic from contaminated water is important for environmental protection and drinking water safety worldwide. In this study, bimetallic metal-organic frameworks (MOFs) with catalytic and adsorptive ef-fects were synthesized and combined with peroxymonosulfate (PMS) for efficient As(III) oxidation and As(III)/As (V) removal. The molar ratio of Fe and Mn precursor was adjusted to balance the adsorption and catalytic processes of As(III) in the system. The results showed that among the Fe/Mn-MOFs and MIL-88(Fe) tested, the Fe/Mn-MOFs with an Fe/Mn molar ratio of 1:1 (Fe0.3Mn0.3-MOFs) could achieve the best catalytic and adsorption performance with 98% removal of As(III). The performance of Fe0.3Mn0.3-MOFs in natural contam-inated water was also verified. Electron spin resonance detection and quenching experiments have revealed that trivalent arsenic oxidation is facilitated primarily by a non-radical process through singlet oxygen. Density-functional theory, XPS and FTIR analyses reveal the structures, corresponding binding energies and binding sites for the adsorption of As(III)/As(V) by Fe0.3Mn0.3-MOFs. The coupling of Fe0.3Mn0.3-MOFs to the PMS system was still able to achieve 78% arsenic removal after five cycles, showing good reliability and effectiveness in arsenic removal. This study provides a new insight into the catalytic and adsorption mechanisms in MOFs/PMS systems and provides a theoretical basis for the application of MOFs in the remediation of arsenic contaminated water.
关键词：
(1)O(2);Catalysts;Generation pathways;Identification methods;PMS system
摘要：
Catalysts for peroxymonosulfate (PMS) activation are appealing in the purification of organic wastewater. Singlet oxygen ((1)O(2)) is widely recognized as a crucial reactive species for degrading organic contaminants in catalysts/PMS systems due to its adamant resistance to inorganic anions, high selectivity, and broad pH applicability. With the rapid growth of studies on (1)O(2) in catalysts/PMS systems, it becomes necessary to provide a comprehensive review of its current state. This review highlights recent advancements concerning (1)O(2) in catalysts/PMS systems, with a primary focus on generation pathways and identification methods. The generation pathways of (1)O(2) are summarized based on whether (distinguished by the geometric structures of metal species) or not (distinguished by the active sites) the metal element is included in the catalysts. Furthermore, this review thoroughly discusses the influence of metal valence states and metal species with different geometric structures on (1)O(2) generation. Various potential strategies are explored to regulate the generation of (1)O(2) from the perspective of catalyst design. Identification methods of (1)O(2) primarily include electron paramagnetic resonance (EPR), quenching experiments, reaction in D(2)O solution, and chemical probe tests in catalysts/PMS systems. The principles and applications of these methods are presented comprehensively along with their applicability, possible disagreements, and corresponding solutions. Besides, an identifying procedure on the combination of main identification methods is provided to evaluate the role of (1)O(2) in catalysts/PMS systems. Lastly, several perspectives for further studies are proposed to facilitate developments of (1)O(2) in catalysts/PMS systems.
通讯机构：
[Xinjiang Hu] C;[Mingshan Zhu] G;College of Environmental Science and Engineering, Central South University of Forestry and Technology, Changsha 410004, PR China<&wdkj&>Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou 511443, PR China
摘要：
Although graphitic carbon nitride (g-C3N4) is frequently mentioned as an environmentally friendly and low-cost photocatalyst, its photocatalytic efficiency is severely constrained by its greater band gap and easy recombination of photogenerated carriers. Introducing nitrogen defects into the photocatalyst can effectively improve the photocatalytic efficiency of g-C3N4. As the position and concentration of inserted nitrogen defects are important factors affecting the catalytic performance of g-C3N4, this review summarized the synthesis methods developed in recent years based on the perspective of the regulation of nitrogen defect position and concentration. Additionally, this study provided an overview of the characterization methods for discovering nitrogen defects and accurately identifying their exact positions in g-C3N4. At the same time, the mechanism of nitrogen defects promoting the photocatalytic performance of g-C3N4 was explored from aspects such as enhancing light absorption, promoting the transfer and separation of photogenerated carriers, and increasing the consumption of photogenerated carriers through surface reactions. Finally, the opportunities and challenges of nitrogen defects in identification, synthesis, and mechanism of action were discussed.
关键词：
17beta-estradiol;Al(2)O(3) nanoparticles;Graphene-like magnetic biochar;Mircoplastics;Potassium ferrate
摘要：
A graphene-like magnetic biochar (GLMB) was synthesized using lotus seedpod and potassium ferrate with simple step and applied for E2 adsorption. GLMB was characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscope (AFM), X-ray photoelectron spectroscopy (XPS), Raman, X-ray diffraction (XRD), vibrating sample magnetometer (VSM) and BET surface area. Several common (solution pH, ionic strength, humic acid and foreign ions) and new (Al2O3 nanoparticles and microplastics (MPs)) water experiment conditions were investigated. Characterization results demonstrated that the sample was fabricated successfully and it possessed some graphene-like properties and a large surface area (828.37 m(2)/g). Adsorption results revealed that the pseudo-second-order kinetics and Langmuir isotherm models could provide a better description for E2 uptake behavior. The E2 adsorption capacity could be influenced by solution pH, ionic strength and SO42- ions, and the effect of humic acid and background electrolyte (Na+, K+, Ca2+, Mg2+, Cl-, NO3-, PO43-) could be neglected. The presences of Al2O3/MPs significantly decreased the time to reach adsorption equilibrium for E2 adsorption on GLMB, but had no obvious improvement or inhibiting effects on E2 removal when the adsorption reached equilibrium. The adsorption mechanism for E2 adsorption on GLMB was multiple, which involving n-n interactions, micropore filling effects, electrostatic interaction. The regeneration experiments showed that GLMB possessed a good regeneration performance. Based on the experimental results and comparative analysis with other adsorbents, GLMB was an economical, high-efficiency, green and recyclable adsorbent for E2 removal from aqueous solution. (C) 2020 Published by Elsevier B.
期刊：
International Journal of Environmental Research and Public Health,2020年17(1) ISSN：1661-7827
通讯作者：
Li, Jiang
作者机构：
[Cai, Xiaoxi] Hunan First Normal Univ, Coll Art & Design, Changsha 410205, Peoples R China.;[Liu, Shaobo; Li, Jiang] Cent S Univ, Sch Architecture & Art, Changsha 410083, Peoples R China.;[Liu, Yunguo; Tan, Xiaofei] Hunan Univ, Coll Environm Sci & Engn, Changsha 410082, Peoples R China.;[Hu, Xinjiang; Wang, Hui; Luo, Lerong] Cent South Univ Forestry & Technol, Coll Environm Sci & Engn, Changsha 410004, Peoples R China.;[Gu, Yanling] Changsha Univ Sci & Technol, Coll Mat Sci & Engn, Changsha 410114, Peoples R China.
通讯机构：
[Li, Jiang] C;Cent S Univ, Sch Architecture & Art, Changsha 410083, Peoples R China.
关键词：
adsorption;biochar;composite;magnetic;methylene blue
摘要：
Biochar obtained by pyrolysis of the fiber plant kenaf was mixed with bismuth ferrite (BiFeO3) in a chitosan-containing acetic acid solution, magnetized, and modified to prepare a chitosan-crosslinked BiFeO3/biochar coupled magnetic material. The adsorption properties of the composite were investigated using methylene blue dissolved in water, and the effects of external conditions, such as pH, methylene blue concentration, reaction time, and temperature, on the adsorption performance were studied. The adsorption data were fitted and analyzed with kinetic and isotherm models, and the results showed that the BiFeO3/biochar coupled magnetic material effectively adsorbed methylene blue. The amounts adsorbed onto this magnetic material increased with increasing initial methylene blue concentration, reaction time, and temperature, and the adsorption performance improved under neutral and alkaline conditions. The pseudo-first-order kinetic and Langmuir isotherm models satisfactorily fitted the adsorption data, showing that the adsorption of methylene blue involved both chemical and physical adsorption. The maximum adsorption capacity of methylene blue onto the BiFeO3/biochar coupled magnetic material reached 18.942 mg.g(-1) at 25 degrees C, confirming the excellent dye binding activity of this material.
作者机构：
[Zhao, Yunlin; Qiu, Guoqiang; Jin, Qi] Cent South Univ Forestry & Technol, Fac Life Sci & Technol, Changsha 410004, Peoples R China.;[Huo, Huiwen; Zhao, Yunlin; Hu, Xinjiang; Wang, Hui; Hu, XJ; Xie, Guangyu; Zhou, Daixi] Cent South Univ Forestry & Technol, Coll Environm Sci & Engn, Changsha 410004, Peoples R China.;[Cai, Xiaoxi] Hunan First Normal Univ, Coll Art & Design, Changsha 410205, Peoples R China.;[Wang, Weixuan] Northwest Normal Univ, Coll Geog & Environm Sci, Lanzhou 730070, Peoples R China.;[Tan, Xiaofei] Hunan Univ, Coll Environm Sci & Engn, Changsha 410082, Peoples R China.
通讯机构：
[Zhao, Yunlin; Hu, XJ; Zhao, YL] C;Cent South Univ Forestry & Technol, Fac Life Sci & Technol, Changsha 410004, Peoples R China.;Cent South Univ Forestry & Technol, Coll Environm Sci & Engn, Changsha 410004, Peoples R China.
摘要：
Photocatalysts comprising Broussonetia papyrifera biochar and g-C3N4 loaded on sodium alginate were prepared and characterized in terms of reusability and photocatalytic Cr(vi) reduction performance. The observed photocurrent responses as well as photoluminescence and UV-visible diffuse reflectance spectra showed that the best-performing catalyst featured the benefits of efficient photogenerated charge separation, superior electron conductance/transfer, and excellent light adsorption ability, which resulted in a higher photocatalytic Cr(vi) reduction performance compared to that of pure g-C3N4 powder. The prepared composite was shown to be reusable and well separable from the reaction mixture, thus being a promising material for the practical photocatalytic removal of Cr(vi) from wastewater. The trapping experiment and XPS spectra of catalysts after reactions confirm that the decontamination of Cr(vi) lies in the photocatalytic reduction of this species into low-toxicity Cr(iii) by photoinduced electrons generated from g-C3N4, followed by the adsorption of Cr(iii) on biochar or alginate with large specific areas.
摘要：
A novel graphite-phase carbon nitride (g-C3N4)/bismuth ferrite (BiFeO3)/carbon nanotubes (CNTs) ternary magnetic composite (CNBT) was prepared by a hydrothermal synthesis. Using this material, Cr(VI) and methylene blue (MB) were removed from wastewater through synergistic adsorption and photocatalysis. The effects of pH, time, and pollutant concentration on the photocatalytic performance of CNBT, as well as possible interactions between Cr(VI) and MB species were analyzed. The obtained results showed that CNTs could effectively reduce the recombination rate of electron-hole pairs during the photocatalytic reaction of the g-C3N4/BiFeO3 composite, thereby improving its photocatalytic performance, while the presence of MB increased the reduction rate of Cr(VI). After 5 h of the simultaneous adsorption and photocatalysis by CNBT, the removal rates of Cr(VI) and MB were 93% and 98%, respectively. This study provides a new theoretical basis and technical guidance for the combined application of photocatalysis and adsorption in the treatment of wastewaters containing mixed pollutants.
通讯机构：
[Wang, Hui; Zhao, Yunlin] C;Cent South Univ Forestry & Technol, Coll Environm Sci & Engn, Changsha 410004, Hunan, Peoples R China.;Cent South Univ Forestry & Technol, Fac Life Sci & Technol, Changsha 410004, Hunan, Peoples R China.
关键词：
g-C3N4 nanosheets;BiFeO3;Cr(VI) photoreduction;Heterojunction;Electrolyte ion
摘要：
A novel ternary composite of graphitic carbon nitride (g-C3N4)/graphene oxide (GO) sheets/BiFeO3 (CNGB) with highly enhanced visible-light photocatalytic activity toward Cr(Vl) photoreduction is prepared and characterized. The characterization and photocatalysis experiments corroborate its reasonable band gap, efficient charge separation and transfer, widened visible-light adsorption, easy solid-liquid separation, good stability and superior catalytic activity of CNGB. Three CNGB samples with different ratios of g-C3N4 and BiFeO3 (CNGB-1, -2, -3 with 2:4, 3:3, and 4:2, respectively), though possessing different adsorption ability, eventually remove all Cr(Vl) ions via photocatalysis within 90 min. The catalytic efficiency of the composite is the highest at pH 2; increases in pH decrease the catalytic ability. The inorganic anions such as SO4-, Cl-, and NO3- only slightly affects the photocatalytic process. The matching of the band structure between BiFeO3 and g-C3N4 generates efficient photogenerated electron migration from the conduction band of g-C3N4 to that of BiFeO3, which is also facilitated by the electron bridging and collecting effects of GO, and holes transfer from the valence band of BiFeO3 to that of g-C3N4, yielding the efficient separation of photogenerated electron-hole pairs and the subsequent enhancement of photocatalytic activity. The research provides a theoretical basis and technical support for the development of photocatalytic technologies for effective application in wastewater treatment and Cr-contaminated water restoration. (C) 2018 Elsevier Ltd. All rights reserved.
摘要：
A novel graphene oxide supported activated magnetic biochar (GO-AMBC) is fabricated for 17 beta-estradiol (E2) removal from aqueous solution by grafting graphene oxide (GO) and magnetite nanoparticles onto the activated biochar surface with a one-step activation, magnetization, and carbonization method. GO-AMBC is characterized using SEM, TEM, FTIR, VSM, XRD, XPS, BET surface area and zeta potential measurements. The characterization results show that GO-AMBC possesses a larger surface area and more oxygen-containing functional groups than the unmodified biochar. When the E2 initial concentration is 6 mg/L, its adsorption capacity by GO-AMBC (46.22 mg/g) is more than two times higher than that of pristine biochar (23.09 mg/g) at 298 K and pH = 7.0. Adsorption results show that E2 uptake follows by pseudo-second-order kinetic and Freundlich isothermal models. Thermodynamic analysis indicates that the adsorption process is spontaneous and exothermic. E2 removal by GO-AMBC is significantly affected by the actual water conditions, including solution pH, ionic strength, and organic acids. Among them, organic acids have obvious inhibition effect on E2 removal, and the inhibition effect by oxalate is stronger than that of benzoate. The adsorption mechanism of E2 on GO-AMBC is mainly controlled by hydrogen bonds, electrostatic and pi-pi interactions. The experimental results of this study and comparative analysis with other adsorbents suggest that GO-AMBC is an economical, efficient and recyclable adsorbent and has great potential for E2 removal from contaminated water. (C) 2019 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.
