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Journal ArticleDOI: 10.1016/J.JHAZMAT.2021.125552

Oily sludge derived carbons as peroxymonosulfate activators for removing aqueous organic pollutants: Performances and the key role of carbonyl groups in electron-transfer mechanism.

02 Mar 2021-Journal of Hazardous Materials (Elsevier)-Vol. 414, pp 125552-125552
Abstract: In this work, low-cost carbon-based materials were developed via a facile one-pot pyrolysis of oily sludge (OS) and used as catalysts to activate peroxymonosulfate (PMS) for removing aqueous recalcitrant pollutants. By adjusting the pyrolysis temperature, the optimized OS-derived carbocatalyst manifested good performance for PMS activation to abate diverse organic pollutants in water treatment. Particularly, an average removal rate of 0.87 mol phenol per mol PMS per hour at a catalyst dosage of 0.2 g L−1 is attained by the OS-derived carbocatalyst, higher than many other documented catalysts. A series of experimental evidences consolidated that organic pollutants were oxidized mainly via electron-transfer mechanism albeit the detection of singlet oxygen (1O2) from PMS activation driven by the OS-derived carbocatalyst. Specifically, the proportion of carbonyl groups (C˭O) in the carbocatalyst adopted with selective modification treatments to tailor the surface chemistry was found to be linearly correlated with the catalytic activity and theoretical calculations demonstrated that the reactions between C˭O and PMS to form surface reactive complexes were more energetically favorable compared to 1O2 generation. Herein, this study not only offers a new strategy for reusing OS as value-added persulfate activators but also deepens the fundamental understanding on the nonradical regime.

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17 results found

Journal ArticleDOI: 10.1016/J.APCATB.2021.120291
Shengjiong Yang1, Shengshuo Xu1, Jiayao Tong1, Dahu Ding2  +4 moreInstitutions (2)
Abstract: Nitrogen was usually doped into carbon matrix to boost its catalytic activity owing to its electronic adjusting activity toward the topological carbon structure. Herein, an overlooked role of nitrogen dopant was unraveled. The nitrogen dopant was firstly incorporated into the carbon matrix and then partially evaporated, leaving the newly generated topological intrinsic defects under high temperature. It was confirmed that peroxymonosulfate (PMS) could be activated by topological defects-rich carbon catalysts. Surface-activated PMS complex was found to be the dominant reactive oxidation species for organic degradation through electron-transfer mechanism. The distinct current density attenuation revealed that N-rich carbon catalysts possessed more effective stoichiometric reaction between the surface-activated PMS and adsorbed organic than topological defects-rich carbon. Findings from this work confirmed the roles of topological defects and extrinsic defects in PMS activation and provided new insight into the synthesis of defects-rich carbon catalysts.

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Topics: Carbon (53%), Dopant (50%)

11 Citations

Journal ArticleDOI: 10.1016/J.JHAZMAT.2021.126113
Lei He1, Mei-Xi Li1, Fei Chen1, Shan-Shan Yang1  +3 moreInstitutions (2)
Abstract: A facile one-step pyrolysis method was employed to prepare an iron containing carbonaceous catalyst using coagulation waste (CW) from paper mill. The catalyst (noted as PMCW) was used to activate peroxymonosulfate (PMS) for decomposition of Reactive Red 2 (RR2). The degradation mechanism was analyzed by reactive oxygen species (ROS) scavenging experiments, electron spin resonance spectroscopy, electrochemical measurements, selective deactivation of the functional groups on the catalyst surface, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy. Results showed that, besides ROS (•OH, SO4•- and 1O2), electron transfer pathways induced by -OH functional groups and the π-π* system are involved in the degradation mechanism of RR2. Concerning different decomposition pathways, seven intermediates were identified, and three important steps, including attack on the azo group, cleaving the N9-C10 bond, and opening the naphthalene ring, were deduced via application and analysis of quadrupole time-of-flight liquid chromatography/mass spectrometry (QTOF LC/MS) and density functional theory (DFT) calculations based on Fukui indices and electrostatic potential (ESP) distributions. This work not only provides a novel facile recycling strategy of industrial waste from paper manufacturing to good carbonaceous catalysts but also deepens the understanding of the mechanisms of PMS activation with carbonaceous materials.

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Topics: Catalysis (50%)

6 Citations

Journal ArticleDOI: 10.1016/J.APCATB.2021.120446
Jun Liang1, Xiaoguang Duan2, Xiaoyun Xu1, Kexin Chen1  +5 moreInstitutions (3)
Abstract: The oxidation efficiency of iron/persulfate coupled system was limited by the sluggish Fe3+/Fe2+ cycle and severe Fe3+ precipitation. In this study, we reported that pyrolytic carbon under low-temperature (PC400) could significantly and continuously accelerate the Fe3+/Fe2+ circulation in the Fe3+-mediated persulfate system. The fast Fe3+/Fe2+ circulation was due to the transformation between semiquinone radicals and quinones on PC400, resulting in the great reusability and continuous degradation of sulfamethoxazole (SMX). In contrast, pyrolytic carbon derived under high temperature (PC700) could not maintain the Fe3+/Fe2+ cycle for continuous SMX degradation. SMX removal in both two systems was barely affected by the presence of chloride and humic acid. Even in the real water matrixes (e.g., seawater, piggery wastewater, and landfill leachate), appreciable SMX removal was obtained because of the nonradical reaction pathways, including high-valence Fe(IV) and surface electron-transfer process, verified by methyl phenyl sulfoxide-based probe tests, Mossbauer spectroscopy, electrochemical test, and kinetic calculation. This study advances the knowledge of Fe3+-mediated persulfate reaction enhanced by pyrolytic carbons. The outcomes will inspire new strategies for developing cost-effective and efficient carbon-accelerated Fenton-like systems.

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Topics: Persulfate (60%), Pyrolytic carbon (50%)

3 Citations

Journal ArticleDOI: 10.1016/J.JHAZMAT.2021.126794
Yanshan Wang1, Yingjin Song1, Ning Li1, Wen Liu2  +6 moreInstitutions (4)
Abstract: Conversion of digestate into biochar-based catalysts is an effective strategy for disposal and resource utilization. The active sites on biochar correlated with reactive species formation in peroxymonosulfate (PMS) system directly. Clarifying the structure-performance relationship of digestate derived biochar in PMS system was essential for decomposition of contaminants. Herein, dairy manure digestate derived biochar (DMDB) was prepared for PMS activation and sulfamethoxazole (SMX) degradation. The higher pyrolysis temperature could promote effective sites generation. Especially, the DMDB-800 catalyst exhibited excellent performance for PMS activation, achieving 90.2% degradation of SMX within 60 min. Based on the correlation analysis between log (k) values and active sites, defects, graphite N and C O were identified as dominant sites for PMS activation. The 1O2 oxidation and surface electron transfer were critical routes for SMX degradation. Besides, the degradation pathways of SMX were proposed according to DFT calculations and intermediates determination. The cleavage of the sulfonamide bond, hydroxylation of the benzene ring and oxidation of the amino group mainly occurred during SMX degradation. Overall, this study provides deep insights into the enhanced mechanism of tunable active sites on DMDBs for PMS activation, boosting the application of digestate biochar for water treatment in advanced oxidation systems.

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Topics: Biochar (57%), Digestate (55%)

3 Citations

Journal ArticleDOI: 10.1016/J.JHAZMAT.2021.127640
Yiqiong Yang1, Wenqing Ji1, Xingyu Li1, Huidong Lin1  +5 moreInstitutions (1)
Abstract: Tetracycline (TC) is a commonly used antibiotic that has gained wide spread notoriety owing to its high environmental risks. In this study, rich carbonyl-modified carbon-coated Fe0 was obtained by pyrolysis of MIL-100(Fe) in an Ar atmosphere, and used to activate peroxymonosulfate (PMS) for the degradation of tetracycline in water. The roles of Fe0, carbon and surface carbonyl on PMS activation were investigated. Fe0 continuously activated PMS, acted as a sustained-release source of Fe2+, and could effectively activate PMS to produce SO4•−, O2•− and •OH. Carbon was found to do responsible for electron transportation during the activation of PMS and slow down the oxidation of Fe0. The carbonyl group on the carbon surface layer was the active site of 1O2, which explains the enhanced performance for TC degradation. When Ca = 0.1 g/L and C0 = 0.4 mM, TC degradation rate reached 96%, which was attributed to the synergistic effect of radicals (i.e., SO4•−, O2•−, •OH) and non-radical (i.e., 1O2). Finally, the degradation pathway was proposed by combining density functional theory (DFT) calculations with liquid chromatography-mass spectrometry (LC-MS), toxicities of the intermediate products were also evaluated. All results show that carbonyl-modified carbon-coated Fe0 possesses promising capacity for the removal of antibiotics from water.

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2 Citations


79 results found

Journal ArticleDOI: 10.1016/J.CEJ.2016.10.064
Farshid Ghanbari1, Mahsa Moradi2Institutions (2)
Abstract: The degradation of refractory organic compounds to harmless matters is one of the major concerns of environmentalists. Advanced oxidation processes (AOPs) are promising technologies producing the hydroxyl and sulfate radicals for pollutant degradation. Recently, much attention has been paid to producing sulfate radicals through activation of peroxymonosulfate (PMS). Nowadays, the use of PMS has acquired popularity thanks to its high reactivity and also to its high potential in generating sulfate radical. Actually it is becoming an alternative for hydrogen peroxide and persulfate. PMS is an unsymmetrical oxidant which can be activated to produce both hydroxyl and sulfate radicals. Various methods of PMS activation have been reported in literature including transition metals (homogenous and heterogeneous), ultraviolet, ultrasound, conduction electron, carbon catalysts and so on. PMS activation has been broadly applied for a wide range of pollutants mostly in aqueous solution. A literature review is carried out on environmental application of PMS in degradation of contaminants to clarify the performance of PMS. This review in detail describes the PMS usage in remediation of environmental pollutants with focus on the different methods of activation and the effect of main operational parameters on PMS-based processes. Moreover, the identification of contribution of each radical is discussed based on quenching experiments and electron spin resonance method. Finally, an overview on applying PMS in real wastewater and other matrixes (air, soil and sludge) is conducted and some recommendations are proposed for future studies.

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977 Citations

Journal ArticleDOI: 10.1021/ES304721G
Tao Zhang1, Haibo Zhu1, Jean-Philippe Croué1Institutions (1)
Abstract: A simple, nonhazardous, efficient and low energy-consuming process is desirable to generate powerful radicals from peroxymonosulfate (PMS) for recalcitrant pollutant removal. In this work, the production of radical species from PMS induced by a magnetic CuFe2O4 spinel was studied. Iopromide, a recalcitrant model pollutant, was used to investigate the efficiency of this process. CuFe2O4 showed higher activity and 30 times lower Cu2+ leaching (1.5 μg L–1 per 100 mg L–1) than a well-crystallized CuO at the same dosage. CuFe2O4 maintained its activity and crystallinity during repeated batch experiments. In comparison, the activity of CuO declined significantly, which was ascribed to the deterioration in its degree of crystallinity. The efficiency of the PMS/CuFe2O4 was highest at neutral pH and decreased at acidic and alkaline pHs. Sulfate radical was the primary radical species responsible for the iopromide degradation. On the basis of the stoichiometry of oxalate degradation in the PMS/CuFe2O4, the radical ...

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Topics: Radical (52%)

611 Citations

Journal ArticleDOI: 10.1016/J.JHAZMAT.2013.07.069
Guangji Hu1, Jianbing Li1, Guangming Zeng2Institutions (2)
Abstract: Oily sludge is one of the most significant solid wastes generated in the petroleum industry. It is a complex emulsion of various petroleum hydrocarbons (PHCs), water, heavy metals, and solid particles. Due to its hazardous nature and increased generation quantities around the world, the effective treatment of oily sludge has attracted widespread attention. In this review, the origin, characteristics, and environmental impacts of oily sludge were introduced. Many methods have been investigated for dealing with PHCs in oily sludge either through oil recovery or sludge disposal, but little attention has been paid to handle its various heavy metals. These methods were discussed by dividing them into oil recovery and sludge disposal approaches. It was recognized that no single specific process can be considered as a panacea since each method is associated with different advantages and limitations. Future efforts should focus on the improvement of current technologies and the combination of oil recovery with sludge disposal in order to comply with both resource reuse recommendations and environmental regulations. The comprehensive examination of oily sludge treatment methods will help researchers and practitioners to have a good understanding of both recent developments and future research directions.

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581 Citations

Journal ArticleDOI: 10.1021/ACS.EST.5B03595
Yang Zhou1, Jin Jiang1, Yuan Gao1, Jun Ma1  +4 moreInstitutions (2)
Abstract: The reactions between peroxymonosulfate (PMS) and quinones were investigated for the first time in this work, where benzoquinone (BQ) was selected as a model quinone. It was demonstrated that BQ could efficiently activate PMS for the degradation of sulfamethoxazole (SMX; a frequently detected antibiotic in the environments), and the degradation rate increased with solution pH from 7 to 10. Interestingly, quenching studies suggested that neither hydroxyl radical (•OH) nor sulfate radical (SO4•–) was produced therein. Instead, the generation of singlet oxygen (1O2) was proved by using two chemical probes (i.e., 2,2,6,6-tetramethyl-4-piperidinol and 9,10-diphenylanthracene) with the appearance of 1O2 indicative products detected by electron paramagnetic resonance spectrometry and liquid chromatography mass spectrometry, respectively. A catalytic mechanism was proposed involving the formation of a dioxirane intermediate between PMS and BQ and the subsequent decomposition of this intermediate into 1O2. Accordi...

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Topics: Benzoquinone (59%), Hydroxyl radical (53%), Dioxirane (51%) ... read more

498 Citations

Journal ArticleDOI: 10.1021/ACS.ACCOUNTS.7B00535
Xiaoguang Duan1, Hongqi Sun2, Shaobin Wang1Institutions (2)
Abstract: ConspectusCatalytic processes have remarkably boosted the rapid industrializations in chemical production, energy conversion, and environmental remediation. As one of the emerging applications of carbocatalysis, metal-free nanocarbons have demonstrated promise as catalysts for green remediation technologies to overcome the poor stability and undesirable metal leaching in metal-based advanced oxidation processes (AOPs). Since our reports of heterogeneous activation of persulfates with low-dimensional nanocarbons, the novel oxidative system has raised tremendous interest for degradation of organic contaminants in wastewater without secondary contamination. In this Account, we showcase our recent contributions to metal-free catalysis in advanced oxidation, including design of nanocarbon catalysts, exploration of intrinsic active sites, and identification of reactive species and reaction pathways, and we offer perspectives on carbocatalysis for future environmental applications.The journey starts with the dis...

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457 Citations