COMPOSITES PART A-APPLIED SCIENCE AND MANUFACTURING
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2023
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IF 8.7
Guangda Guo,Fang Ye,Laifei Cheng,Zhaochen Li,Litong Zhang
SiC/SiC composites, prepared by reactive melt infiltration (RMI), exhibit exceptional properties. However, the presence of residual Si in the composite matrix can significantly compromise their high-temperature mechanical properties. Addressing the issue of high-content residual Si aggregation remains a crucial focus of research in order to fully unlock the application potential of SiC/SiC composites prepared by RMI. In this work, a special porous carbon (C g ) is successfully synthesized and introduced into the porous 2D SiC/SiC composites prepared by CVI. The unique pore structure of the SiC/SiC-C g is thoroughly analyzed, along with its liquid Si infiltration process. The difference in coefficient of thermal expansion (CTE) between SiC and C g can cause thermal stress, which can destory the C g structure. Consequently, the C particles detach from the C g skeleton and react with liquid Si to create SiC. This process effectively separates residual Si and helps alleviate the negative effects of residual Si aggregation. The microstructure and phase distribution of SiC/SiC composites obtained by liquid Si infiltrating different C structures are investigated and compared, and it demonstrates the positive effect of C g on the uniform phase distribution of matrix in the composites. The as-received SiC/SiC composites possess a density of 2.94 g/cm 3 with open porosity of 1.23 %, and a flexural strength of 808.7 ± 10.2 MPa, a fracture toughness of 25.5 ± 1.8 MPa·m 1/2 , a tensile strength of 317.4 ± 12.4 MPa and a proportional ultimate stress of 157.33 ± 4.1 MPa. Acoustic emission (AE) and digital image correlation (DIC) technology are used to study the special mechanical behavior of composites.
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JOURNAL OF HAZARDOUS MATERIALS
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2023
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IF 13.6
Afang Wang,Yang Shi,Yang Liu,Wei Li,Heng Zhang,Xiaoqiang Dai,Li Luo,Gang Yao,Bo Lai
Traditional Fenton and Fenton-like processes are affected by the sluggish kinetics of Fe(II) regeneration and Fe(III) accumulation. This research revealed that the degradation efficiency of pollutants was significantly increased by adding Fe(III) to the Vis/PS system. A mechanism is proposed in which photosensitivity pollutants can boost Fe(III) to produce Fe(II) under visible light irradiation. Intriguingly, Fe(III) rapidly combines with LVF in aqueous environments to form Fe(III)-LVF complexes. This research confirms that Fe(III)-pollutant complexes are generated. The proportion of complexes are calculated using mathematical models. Furthermore, the production of Fe(IV) is verified in the Vis/PS/Fe(III) system, which also plays a vital role in boosting LVF degradation. Overall, this study provides comprehensive insights into the degradation mechanism of micropollutants, involving hydroxyl radical ( OH ∙ ), Fe(IV), and Fe(III)-LVF complexes, providing an efficient and green strategy for contaminant removal during wastewater treatment .
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RSC Advances
·
2023
·Vol. 13
·期 42
·29695-29705
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IF 3.9
Hui Fui,Shumin Gao,Xinran Ma,Yiping Huang
Layered double hydroxides (LDHs) have been extensively investigated as promising peroxymonosulfate (PMS) activators for the degradation of organic pollutants. However, bulk LDHs synthesized using conventional methods possess a closely stacked layered structure, which seriously blocks active sites and yields low intrinsic activity. In this study, we exfoliated bulk CoAl-LDHs to fabricate CoAl-LDH nanosheets by alkali-etching and Ostwald ripening via a simple hydrothermal process in a KOH solution. The exfoliated LDHs possessed the typical nanosheet structure with more exposed active sites for PMS activation, and hence, boosted the degradation of the pollutants. CoAl-1 exhibited an outstanding catalytic performance as the PMS activator for rhodamine B (RhB) degradation with the apparent rate constant of 0.1687 min−1, which was about 3.63 and 5.02 times higher than that of commercial nano-Co3O4 and bulk CoAl-LDH, respectively. The maximum RhB degradation of 93.1% was achieved at the optimal reaction conditions: catalyst dose 0.1 g L−1, PMS concentration 0.3 mM, pH 7, and temperature 298 K. Further analysis of RhB degradation mechanism illustrated that singlet oxygen (1O2) dominated RhB degradation in the CoAl-1/PMS system, while ˙OH, ˙O2−, and ˙SO4− may mainly serve as the intermediates for the generation of 1O2 and were indirectly involved in the degradation. This study provides a promising strategy for developing two-dimensional LDH nanosheets for wastewater remediation.
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CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Xi Chen,Yunfeng Chen,Songrong Li,Cheng Xue,Dongfang Liu,Wenli Huang
Phthalic acid esters (PAEs) pose serious health risks to humans and are difficult to remove by conventional sewage treatment processes. Herein, Fe 2 Mo 3 O 8 /MoO 2 /Mo 2 N composite (FMON) derived from bimetallic organic framework was used to activate peroxymonosulfate (PMS) for dibutyl phthalate (DBP) degradation. FMON exhibited an excellent catalytic effect with DBP removal efficiency of 92.4 % within 60 min. Mo 2 N showed a superior ability in promoting Fe 3+ /Fe 2+ redox cycle. The reduction efficiencies of Fe 3+ by Mo 2 N/MoO 2 composite and MoO 2 were 67 %–94 % and 11 %–23 %, respectively, in the homogeneous comparative experiment. Moreover, the ratio of Fe 2+ /Fe 3+ in FMON increased significantly after the catalytic reaction. Fe element doping also enhanced the reuse stability and reduced the metal ion leaching of the catalyst. The degradation of DBP was mediated by a variety of reactive species, of which SO 4 − , OH and O 2 − were dominant. Fe element, Mo element and O vacancies were confirmed to exert significant contributions as active sites in the catalytic process. Three degradation pathways of DBP were obtained by DFT calculation and HPLC-MS analysis. And the toxicity of DBP degradation products was significantly reduced based on the assessment result of Toxicity Estimation Software Tool (T.E.S.T.). This study explored a novel Fe/Mo bimetallic catalyst with friendly Fe 3+ /Fe 2+ cycling for environmental catalysis and provided new ideas for the treatment of PAEs wastewater.
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ENVIRONMENTAL POLLUTION
·
2023
·
IF 8.9
Zhuoyue Wang,Ji Li,Wei Song,Jingxin Yang,Wenyi Dong,Xiaolei Zhang
Recently, it has been reported that chlorine dioxide (ClO 2 ) and (bi)sulfite/ClO 2 showed excellent performance in micropollutant removal from water; however, the degradation mechanisms and application boundaries of the two system have not been identified. In this study, bisphenol A (BPA) was chosen as the target contaminant to give multiple comparisons of ClO 2 and S(IV)/ClO 2 process regarding the degradation performance of contaminant, generation of reactive species, transformation of products and toxicity variation. Both ClO 2 and S(IV)/ClO 2 can degrade BPA within 3 min. The BPA degradation mechanism was mainly based on direct oxidation in ClO 2 process while it was attributed to radicals (especially SO 4 · - ) generation in S(IV)/ClO 2 process. Meanwhile, the effect of pH and coexisting substances (Cl − , Br − , HCO 3 − and HA) were evaluated. It was found that ClO 2 preferred the neutral and alkaline condition and S(IV)/ClO 2 preferred the acidic condition for BPA degradation. An unexpected speed-up of BPA degradation was observed in ClO 2 process in the presence of Br − , HCO 3 − and HA . In addition, the intermediate products in BPA degradation were identified. Three exclusive products were found in ClO 2 process, in which p-benzoquinone was considered to be the reason of the acute toxicity increase in ClO 2 process.
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CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Siyu Ma,Zhihao Wang,Bowen Liu,Xiaolei Wang,Shichao Du,Zichen Song,Xinxin Bian,Manchen Hao,Ju Huang,Zhimin Chen,Zhiyu Ren
Pairing the hydrogen evolution reaction (HER) with the thermodynamics-friendly electrooxidation reaction (EOR) is a powerful way to maximize the energy/economic effectiveness, but still a challenge. Herein, the symbiotic Ni/MoN heterojunction arrays were constructed on foam (Ni/MoN/NF) by the nitridation-induced in situ reduction/conversion strategy. The fascinating interfacial electronic structure and surface reconstruction of Ni/MoN/NF heterojunction are responsible for the enhanced HMF-H 2 O paired electrolysis. Ni/MoN/NF only requires a low overpotential of 53 mV to reach the HER current density of 10 mA cm −2 , as well as the good durability; and NiOOH derived on the anode are electronically activated by MoN to achieving high-efficiency conversion from HMF to FDCA (∼100 % conversion, 97.5 % yield and 97.4 % Faradaic efficiency). For the HMF-H 2 O paired electrolysis, the assembled Ni/MoN/NF||Ni/MoN/NF electrolyzer only requires a low potential of 1.391 V to yield the current density of 10 mA cm −2 , ranking at the forefront in the reported coupling catalysts. Theoretical calculations manifest that the upshift of d -band center of the NiOOH/MoN heterojunction contributes to HMF chemisorption and activation, thereby enhancing its catalytic activity towards HMFEOR. Our study sheds light on the significance of designing the paired electrolysis with low voltage input for renewable energy applications.
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Journal of Environmental Chemical Engineering
·
2023
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IF 7.7
Meiling Chen,Lin Ding,Shijun Zhu,Xiuqin Xiong,Xinkai Yuan,Yanhua Peng,Liming Yang,Hui Shi,Penghui Shao,Xubiao Luo
The slow Fe(II)/Fe(III) cycle during the Fenton reaction process strongly impedes oxidation efficiency in practical applications. In this study, an activated carbon (AC) assisted Fenton reaction system was used to treat electroplating wastewater containing Ni-ethylenediaminetetraacetic acid (Ni-EDTA). AC was found to enhance the removal of Ni-EDTA in Fenton/Fenton-like reactions. The reported results revealed that AC could effectively promote the regeneration of Fe(II) from Fe(III) species via electron transfer to improve the reaction rather than directly enhancing the H 2 O 2 decomposition to accelerate the production of hydroxyl radicals (•OH). Quenching experiments and EPR also demonstrated that •OH and •O 2 − took part in the radical oxidation process, in which the contribution of •OH was dominant. XPS and FT-IR analysis further confirmed that the carbonyl group (C O) on the surface of AC could indeed act as the dominant active site and an electron donor to directly reduce Fe(III). In addition, electrochemical tests indicated that AC could increase the oxidation potential of Fe(III) to boost the reaction between Fe(III) and H 2 O 2 , thus enabling the transfer of electrons from H 2 O 2 to Fe(III) to facilitate the Fe(II)/Fe(III) cycle. This study might contribute to a new insight into the mechanisms of AC-catalyzed Fenton oxidation processes for the decomplexation heavy metal-EDTA.
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APPLIED CATALYSIS B-ENVIRONMENTAL
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2023
·
IF 22.1
Yizhen Cheng,Jing Kang,Pengwei Yan,Jimin Shen,Zhonglin Chen,Xinwei Zhu,Qiang Tan,Linlu Shen,Shuyu Wang,Shaobin Wang
Herein, a highly dispersed catalyst (ZnO x -500) was synthesized for heterogeneous catalytic ozonation (HCO), which had a simple ZnO crystal phase but riched in oxygen vacancies (OVs). The O 3 /ZnO x -500 system exhibited both superior catalytic activity and stability after several cycles, providing a promising strategy for atrazine (ATZ) removal. The strong inhibition of phosphoric acid validated the dominant role of the hydroxyl group (−OH) from water molecule (H 2 O) dissociation on the zinc site near OVs. Density functional theory calculation further revealed that OVs on (100) and (101) planes could make more zinc sites exposed and facilitate the formation of hydrated −OH, which was easier to approach O 3 for its decomposition to generate hydroxyl radical ( • OH). This work revealed the intrinsic relationship between OVs and hydrated −OH in an aqueous solution, providing new insight into the solid-liquid interface mechanism of HCO.
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CHEMOSPHERE
·
2023
·
IF 8.8
Huiwang Dai,Jingyi Zhu,Fanxu Meng,Daohui Lin,Wenjun Zhou,Dingjiang Chen,Ming Zhang,Qingqing Wang
In this study, Cu hybridization coupling oxygen defect engineering was adopted to synthesis of CuNiFe layered double oxides (CuNiFe-LDOs) in peroxymonosulfate (PMS) activation for degradation of methyl 4-hydroxybenzoate. The morphology and crystal structure of CuNiFe-LDOs was characterized in detail, which exhibited regular layered-structure at a Cu:Ni doping ratio of 1:1 and annealing temperature of 400 °C, and presented the crystal of Cu x O@Fe 3 O 4 –NiO. Besides, the X-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance (EPR) results demonstrated that abundant oxygen vacancies (OVs) and low oxidation state Cu species were composed in CuNiFe-LDOs400. The Cu 1·5 Ni 1·5 Fe 1 -LDOs400/PMS system showed excellent catalytic performance toward the degradation of butyl 4-hydroxybenzoate (BuP), and resistant to the effect of pH value and background inorganic anions. Based on quenching experiments and EPR measurements, singlet oxygen ( 1 O 2 ) was identified as the dominant active species during the heterogeneous catalytic process, which was generated by the synergistic interaction between OVs-Cu(I) site and PMS . In this process, the electron-drawing property of OVs promoted the adsorption of PMS molecule on Cu(I) site, followed by the accumulation of electron and cleavage of O–O bond to generate intermediate oxygen radical species, which donated one electron to eventually generate singlet oxygen.
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Environmental Science-Nano
·
2023
·Vol. 10
·期 11
·3111-3121
·
IF 7.3
Jiaqi Bu,Hongru Jiang,Tianhao Li,Chengyun Zhou,Shian Zhong
In the electrocatalytic (EC) degradation process, low current efficiency, mineralization efficiency, and mass transfer efficiency have limited its widespread application. To overcome these limitations, spherical particle electrodes (LZT–SO) with high electrocatalytic activity were simply prepared by using lead–zinc tailings (LZT) as catalytically active substances and soil (SO) from riverbeds as the carrier. The LZT–SO electrode was introduced into an electrocatalytic (EC) reaction tank to establish a three-dimensional catalytic oxidation system (EC/LZT–SO). Compared with the EC (0.0118 min−1) and EC/SO (0.0271 min−1) systems, the EC/LZT–SO system exhibited a higher sulfamethoxazole (SMZ) degradation rate (0.0597 min−1). EPR analysis and free radical capture experiments confirmed that ·OH played a major role in the degradation process. SEM + EDS analysis confirmed that Fe and Mn metal oxides were the main active sites of the LZT–SO electrode. Under complex water conditions, the degradation efficiency of SMZ reached 94–100% within 70 min. Even after three cycles, the EC/LZT–SO system still maintained a high removal efficiency of 93.75% for SMZ, with only a slight decrease of 6.25%. Triple quadrupole liquid chromatography-mass spectrometry (LC-MS) and Toxicity Estimation Software Tool (TEST) software were used to study the products after SMZ degradation and it was found that the products were almost harmless. This work will provide a new perspective for the “treat waste with waste and turn waste into treasure” approach, which can accelerate the development of recycling waste tailings.
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WATER RESEARCH
·
2023
·
IF 12.8
Xiaoting Gao,Xianshi Wang,Jun Ma,Yanan Liu
Disinfection by-products (DBPs) with significant teratogenic and carcinogenic properties have become a growing concern among the public. As an efficient and environmentally friendly technology, non-thermal plasma offers potential for removing emerging micro-pollutants. In this study, the degradation performance of bubbling corona discharge was evaluated on 24 halogenated alicyclic and aliphatic DBPs present in drinking water at concentrations ranging from ng/L to μg/L. The degradation of DBPs followed pseudo-first-order kinetics with rate constants ( k obs ) in the descending order of halonitromethanes (HNMs), halogenated benzoquinones (HBQs), haloacetonitriles, trihalomethanes (THMs), haloketones, halogenated aldehydes, and haloacetic acids (HAAs). THMs, HNMs, and HBQs were effectively removed within 5 min under a discharge power of 28 W. Degradation rates achieved by plasma treatment surpass those of other conventional treatment technologies. The required energy consumption was in the range of 5–30 kW·h/m 3 /order. Furthermore, the study investigated the effects of discharge power, initial concentration, and economic analysis on the degradation of four selected DBPs as representatives of mono-, di- and multi-carbon-containing DBPs, namely chloroform (TCM) and bromoform (TBM), tribromoacetic acid (TBAA), and 2,3,5,6-tetrachloro-1,4-benzoquinone (TetraC-BQ). Reactive radicals in the plasma system were investigated using electron paramagnetic resonance, optical emission spectroscopy, fluorimetry, and radical scavengers. Hydrated electrons and hydroxyl radicals played an important role in the removal of DBPs. The intermediates generated during the degradation of TCM, TBM, TBAA, and TetraC-BQ were identified, and the possible degradation pathways for mono- and binary C-DBPs and HBQs were deduced. The breakdown of HBQs did not produce secondary contamination with aliphatic DBPs. The carbon in DBPs was primarily converted to formic acid, acetic acid, and oxalic acid, and the halogens were mainly converted to halogen ions. Additionally, luminescent bacteria toxicity testing confirmed that plasma treatment could reduce the acute toxicity of water samples. These findings demonstrate the potential of plasma treatment as a post-treatment device at the household level.
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CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Guojuan Qu,Peng Jia,Tao Zhang,Shuai Tang,Md. Nahid Pervez,Yixiong Pang,Bin Li,Chengjin Cao,Yaping Zhao
Doping nonmetallic heteroatoms into carbonaceous materials is a proven strategy for enhancing peroxymonosulfate (PMS) activation in the degradation of endocrine-disrupting compounds (EDCs). Understanding the role of heteroatom doping defects and intrinsic defects (topological, vacancies, or edge defects) on PMS activation is crucial for designing more efficient carbon catalysts. Herein, we synthesized nitrogen (N) and phosphorus (P) co-doped carbon microspheres (NPCs) through the pyrolysis of aminophosphonic acid resin (D418) precursors and utilized them to activate PMS for bisphenol A (BPA) degradation. The pyrolysis temperature was found to regulate the type and degree of defects, as well as the configuration of N and P. NPC-1000 (pyrolysis temperature at 1000 °C) exhibited the highest reaction rate constant ( k ) (1.20 × 10 −1 min −1 ) with the lowest N and P doping defects and the highest intrinsic defect intensity resulting from the removal of N and P during pyrolysis. Density functional theory (DFT) calculations and correlation analysis between defect sites and k suggest that the adsorption of PMS was facilitated by graphitic N-coordinated C and intrinsic defect sites rather than P doping defect sites, resulting in the degradation of BPA through electron transfer and radical mechanisms, specifically superoxide radicals (O•–2). Excess halide anions led a significant increase of k with only a limited formation of trichloromethane (TCM) (disinfection byproducts) in presence of 100 mM Cl − . This research offers fundamental insights into constructing intrinsic defects through regulating heteroatom configuration, intending to enhance the catalytic activity of metal-free materials.
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