SEPARATION AND PURIFICATION TECHNOLOGY
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2023
·
IF 8.6
Xueqin Wang,Tiesen Li,Chan Wang,Qingyan Cui,Tinghai Wang,Xiaojun Bao,Yuanyuan Yue
Designing a cost-effective and fast fabrication Cu-SSZ-13 with improved selective catalytic reduction of NO by ammonia (NH 3 -SCR) performance remains an open question. Here we report that LaCe-SSZ-13 zeolites were synthesized from spent fluid catalytic cracking catalyst within 12 h. After ion-exchanging with CuSO 4 solution, the obtained LaCeCu-SSZ-13 catalysts exhibit significantly higher catalytic activity and hydrothermal stability than conventional Cu-SSZ-13. Various characterizations reveal that La and Ce modification not only facilitates the disperse of isolated Cu 2+ species, but also effectively mitigates dealumination and inhibits copper species aggregation after hydrothermal aging. In-situ diffuse reflection infrared Fourier transform spectrum analyses demonstrate that La and Ce modification can accelerate the adsorption capacity for NH 3 and NO x and promote the decomposition of NH 4 NO 3 intermediate species on the catalyst, benefiting the improvement of low-temperature activity. The combination of experiments and theoretical calculations further demonstrate that the most stable positions of La and Ce are on different eight-membered rings in SSZ-13, and then Cu 2+ ions tend to enter eight-membered rings to enhance the NH 3 adsorption capacity and decrease the H 2 O adsorption capacity, which results in higher low-temperature activity and hydrothermal stability than Cu-SSZ-13. Our work provides a feasible strategy for preparing the efficient rare-earth-modified Cu-zeolite based NH 3 -SCR catalyst for nitrogen oxide abatement.
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CHEMOSPHERE
·
2023
·
IF 8.8
Zeyi Wang,Rong Su,Maojie Zhao,Luyao Zhang,Lu Yang,Feng Xiao,Weishan Tang,Lichuan Chen,Ping He,Dingming Yang
The application of PbO 2 for electrochemical oxidation technology is limited by its low electrocatalytic activity and short service life. Herein, based on the facile one-step electrodeposition , we prepared a boron carbide (B 4 C) and cerium (Ce) co-modified Ti/PbO 2 (Ti/PbO 2 –B 4 C–Ce) electrode to overcome these shortcomings. Compared with Ti/PbO 2 electrode, the denser surface is displayed by Ti/PbO 2 –B 4 C–Ce electrode. Meanwhile, electrochemical characterization indicates that the introduction of B 4 C and Ce significantly enhance the electrochemical performance of PbO 2 electrode. In degradation experiments, under optimized conditions (current density 20 mA cm −2 , pH 9, 0.15 M Na 2 SO 4 and 30 °C), the fully degradation of tetracycline (TC) can be completed within 30 min. Furthermore, the trapping experiment demonstrates that ∙OH and SO 4 ·- radicals have a synergistic effect in the degradation process of TC. Based on results of liquid chromatography-mass spectrometer, the generated ·OH preferentially attacks amides, phenols and conjugated double bond groups in TC. Importantly, Ti/PbO 2 –B 4 C–Ce electrode maintains a constant degradation efficiency even after 10 recycling tests, and its service life is 2.4 times of traditional Ti/PbO 2 electrode. Hence, Ti/PbO 2 –B 4 C–Ce electrode is a promising electrode for degradation of organic wastewater containing amides, phenols, and conjugated double bond groups.
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APPLIED CATALYSIS A-GENERAL
·
2023
·
IF 5.5
Jiasheng Wang,Qingrong Wang,Mengdi Zhao,Ming Bao
Toluene gas-phase oxidation is a green, chlorine-free production process for benzaldehyde but its conversion efficiency is still unsatisfying due to the lack of highly efficient catalyst. Here the selective oxidation of toluene to benzaldehyde over V-Ag-Ce/TiO 2 under an air atmosphere was investigated. The catalyst was prepared by impregnation and characterized by scanning electron microscope (SEM), N 2 adsorption-desorption, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Electron paramagnetic resonance (EPR), H 2 temperature programmed reduction (H 2 -TPR), O 2 temperature programmed desorption (O 2 -TPD), and NH 3 temperature programmed desorption (NH 3 -TPD). The amount of oxygen vacancy and acid of the catalyst can be tuned through adjusting the V:Ag:Ce ratio. Over the optimum catalyst (V:Ag:Ce = 4:2:1, molar ratio), 92% benzaldehyde selectivity with a 27% toluene conversion can be obtained at 550 °C. Medium amounts of oxygen vacancy (0.43) and acidity (0.10 mmol/g) are found to be conducive to the conversion of toluene to benzaldehyde. This study has important theoretical guiding significance for improving conversion efficiency from toluene to benzaldehyde by gas-phase aerobic oxidation.
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MATERIALS RESEARCH BULLETIN
·
2023
·
IF 5.4
Luyao Jin,Xintao Xu,Yanghui Wang,Jiaying Li,Kaihao Fan,Bo Hu,Yi Shen,Xuesong Liu
A series of MnO x /TiO 2 based NO x reduction catalyst was prepared by excessive impregnation method. The catalyst was modified by Ce, W and oxidizing agent H 2 O 2 . Mn-Ce/Ti-H and Mn-Ce-W/Ti-H catalysts exhibit the best low temperature activity (nearly 80% NO x conversion at 155–325 °C) and the widest active temperature range (nearly 80% NO x conversion at 180–420 °C), respectively. Property and structure of the modified catalyst were characterized by XRD, TEM, XPS, H 2 -TPR, NH 3 -TPD, etc. It is found that oxidizing agent H 2 O 2 , as well as the high dispersion and specific surface area, can increase the amount of Mn 4+ , Ce 3+ and active oxygen sites on catalyst surface, and the synergistic interaction between Mn and Ce facilitated redox process of the catalysts. These can improve the low temperature activity of the catalyst by facilitating “fast SCR” reaction. The addition of W increased acidity of the catalyst and improved high temperature catalytic activity of the catalyst.
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CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Shanhai Zhao,Yidan Luo,Chunhe Li,Kuankuan Ren,Yanyan Zhu,Weidong Dou
The synthesis of renewable fuel by CO 2 reduction is a promising research direction. The CO 2 reduction reaction may be promoted using photothermal catalysis to achieve efficient CO 2 conversion under mild conditions. In this context, designing efficient catalysts is urgent. In this work, ABO 3 (A = La, Ce; B = Ni, Co, Fe) perovskite catalysts were prepared by coprecipitation and calcination . Experimental results show that the A-site ions and B-site ions in ABO 3 perovskite nanomaterials have a great influence on their structure and photothermal catalytic performance. Among them, the LaNiO 3 catalyst shows excellent photothermal catalytic performance in the conversion of CO 2 to CO and CH 4 , which can generate 0.16 mmol g −1 h −1 CO and 1.38 mmol g −1 h −1 CH 4 at low CO 2 and H 2 concentrations. For the LaNiO 3 sample, its enhancement of catalytic performance mainly benefits from the largest number of active sites, the fastest carrier transport rate, and a relatively suitable band edge position compared with other catalysts. This study proposes a new method for improving the activity and selectivity of photothermal CO 2 reduction and offers a new direction for the recycling of waste gas.
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Journal of Environmental Chemical Engineering
·
2023
·
IF 7.7
Haofei Ma,Ziqi Wang,Peng Yuan,Boxiong Shen,Jie Xu
Since the yield of titanium-bearing blast furnace slag (TF) during the smelting of vanadium titanium magnetite is large, it is urgent to find ways to recycle it and implement its value-added utilization. In this study, a perovskite-rich photocatalyst was prepared by acid-washing of TF, and then Ce was doped to modify it for photocatalytic removal of gaseous toluene under the irradiation of visible light. XRD, XRF and XPS analyses demonstrated that the perovskite phase was enriched after the acid-washing, and the content of CaTiO 3 in the acid-washed slag (AS) also increased after Ce doping. The combined N 2 adsorption-desorption, UV Vis DRS, EIS, PL , and ESR analysis results indicated that the photocatalytic performance of the mentioned photocatalyst was related to the Ce dopant content. The AS doped with 20% Ce (20% Ce-AS) had a lower band gap and larger specific surface area than the others catalysts. Under visible light radiation , more active radicals were produced, and the removal efficiency of toluene reached 92.08% for 20% Ce-AS. In addition, the results of the in situ DRIFTS tests indicated that toluene was gradually degraded by the Ce-doped perovskite-type photocatalyst to alcohols and aldehydes and mineralized to H 2 O and CO 2 . This study is expected to provide a new approach for the technical development of the value-added utilization of TF coupled with the efficient removal of toluene.
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JOURNAL OF HAZARDOUS MATERIALS
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2018
·
IF 6.434
Xueyue Mi,Jingjing Han,Yan Sun,Yi Li,Wenping Hu,Sihui Zhan
Development of an efficient cathode in advanced oxidation process is an important challenge. In this work, we synthesized a low-cost, high-catalytic-active and stable reduced graphene oxide (RGO)-Ce/WO 3 nanosheets (RCW) to modify carbon felt (CF) as cathode to degrade ciprofloxacin (CIP) in electro-Fenton process. Compared to traditional heterogeneous electro-Fenton process, carbon black was substituted by RGO and poly tetra fluoroethylene was avoided to be used as binder. We found that RCW/CF cathode reached about 100% degradation efficiency of CIP after 1 h and 98.55% mineralization degree after 8 h. Meanwhile, it had a very high current density, about 2.5 times that of CF. RCW/CF cathode produced more O 2 − , H 2 O 2 and OH via one-electron reduction process (O 2 → O 2 - →H 2 O 2 ). The modified cathode kept a stable performance for high CIP degradation efficiency during 5 cycles. The introduction of RGO could promote electron transfer, and the adding of Ce into the WO 3 lattice provided superior conditions for the adsorption and activation of oxygen molecules, thus promoting the formation of active oxygen species on the surface of RCW. This novel RCW/CF composite is an efficient and promising electrode for removal of CIP in the wastewater.
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Journal of Materials Chemistry B
·
2019
·Vol. 7
·期 38
·5834-5841
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IF 5.047
Hongwei Song,Kun Ye,Yinxian Peng,Linjie Wang,Xiangheng Niu
Alkaline phosphatase (ALP) is widely recognized as a significant biomarker for lots of diseases. For this reason, developing effective and simple methods to monitor ALP activity is strongly necessary. Herein, we propose a novel strategy based on the target-induced valence state regulation of oxidase-mimicking Ce-based nanorods for ALP activity sensing. The mixed-valent Ce-based material (MVCM) with a relatively high Ce(IV)/Ce(III) ratio can exhibit good oxidase-like activity to trigger the catalytic oxidation of colorless 3,3′,5,5′-tetramethylbenzidine (TMB) to blue TMBox in the presence of O2, resulting in a notable chromogenic reaction. When ALP hydrolyzes ascorbic acid phosphate into ascorbic acid (AA), the formed AA induces the partial reduction of the MVCM to one with a low Ce(IV)/Ce(III) ratio, which shows much less activity to trigger the chromogenic reaction. According to the above principle, a facile colorimetric assay was developed for ALP activity detection, providing a linear range of 0.5–25 U L−1 and a limit of detection of 0.1 U L−1. Besides, the proposed strategy could offer favorable selectivity for ALP activity determination. Accurate sensing of the target in serum was demonstrated by our assay as well, revealing its promise as a reliable tool for clinical diagnosis.
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BRAZILIAN JOURNAL OF CHEMICAL ENGINEERING
·
2018
·Vol. 35
·期 1
·147-154
·
IF 0.925
Liu Junwei,Yun Zhi,Gui Xia
An efficient solid acid catalyst (Ce/Kaolin clay) was prepared and investigated for transesterification of cottonseed oil to fatty acid methyl esters (FAME). The catalysts were characterized by XRD, BET, and NH3-TPD measurements. A new integrated apparatus for extraction and transesterification of cottonseed oil was developed. The effects of cerium loading, catalyst calcination temperature, methanol flow rate, reaction temperature, reaction time, and catalyst amount were also investigated. The results indicated that the Ce/Kaolin clay showed high catalytic activity under the calcination temperature of 700 oC and cerium loading of 0.05 g/g. The optimum transesterification reaction conditions were as follows: methanol flow rate 4.0 mL/min, reaction temperature 60 oC,reaction time 3 h, and catalyst amount 15 g. Under these conditions, the yield of FAME was up to 91%.The catalytic activity of Ce/Kaolin clay still remained high after 4 times of repeated use. The results indicated that the Ce/Kaolin clay catalysts had a good potential for use in the large-scale production of FAME.
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Journal of Environmental Chemical Engineering
·
2024
·
IF 7.4
Tao Huang,Dongping Song,Zhengfeng Hu,Yuxuan Feng,Jialin Cui,Mengyue Wu,Di Wu,Yinglan Luo,Yue Li,Yirong Jiang,Chaojun Tang,DanDan Wang
The urgent need for remediation of thallium (Tl)-contaminated soils arises from its widespread presence as a poisonous heavy metal (HM), coupled with numerous challenges such as high costs, long durations, secondary pollution risks, and technological limitations. In the study, a novel approach has been introduced to the remediation of Tl-contaminated soils using calcium sulphoaluminate cement. This innovation involves the employment of nonthermal plasma-irradiated polyvalent Ce-Mn (hydro)oxide-modified nanographene (NTP-P-Ce-Mn-NGs) to intensify the cementation and immobilization of Tl species. The chemical speciation of Tl contaminants influenced by the dosage of NTP-P-Ce-Mn-NGs in the cementation was measured to explore the potential enhancement mechanisms brought by NTP-P-Ce-Mn-NGs in the sulphoaluminate cementation. Comprehensive strategies were adopted to explore the reaction pathways. In orthogonal (OD) experiments, compressive strengths ranging from 22.14 to 56.78 MPa in sulphoaluminate-cemented cubes were achieved. Remarkably, when NTP-P-Ce-Mn-NGs were introduced, the leached Tl concentration was reduced to 0.21–21.46 µg/L. This significant reduction was attributed to the NTP-P-Ce-Mn-NGs-induced more uniform hydration reactions and a more holistic microstructure. The presence of diverse valent Ce and Mn species within the matrix was confirmed, revealing a reliable interaction between NTP-irradiated high-valent Mn and Ce with monovalent Tl ions. This interaction induced multiple redox reactions, immobilizing Tl contaminants within the matrix and the cementation encapsulation. This study represents a significant milestone in Tl pollution control, paving the way for more efficient and cost-effective soil remediation strategies.
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ELECTROPHORESIS
·
2012
·Vol. 33
·期 11
·1589-1594
·
IF 3.303
Lin Wang,Ying Liu,Haoyue Xie,Zhifeng Fu
A transition metal chelate unstable at a high oxidation state, diperiodatocuprate (III) (K 5 [Cu(HIO 6 ) 2 ], DPC), was synthesized and applied in the luminol-based chemiluminescence (CL) system for highly sensitive CE end-column detection of dopamine (DA). This method was based on the fact that DA enhanced the CL emission resulting from the reaction between luminol and DPC in alkaline medium. The DPC-luminol-DA CL system showed very intensive emission and very fast kinetic characteristics, thus resulting in a high sensitivity in flow-through detection mode for CE. Under optimal conditions, the linear range was 1.0 × 10 −8 –5.0 × 10 −5 g/mL ( R 2 = 0.9984) with a limit of detection of 6.0 × 10 −9 g/mL (S/N = 3). The RSDs of the peak height and the migration time were about 4.2 and 2.4% for a standard sample at 3.0 × 10 −6 g/mL ( n = 5), respectively. The presented method has been successfully used for the determination of DA in commercial preparation and human urine samples after clean-up using SPE.
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JOURNAL OF HAZARDOUS MATERIALS
·
2024
·
IF 12.2
Zhixiang Xu,Dongshan Chen,Xingyu Duan,Yuning Chen,Caiqing Li,Siyuan Li,Yitao Ma,Bin Huang,Xuejun Pan
Dissolved inorganic and organic phosphorus is a major factor in triggering the eutrophication of water bodies. At present, a novel Zr 4+ cross-linked sodium alginate encapsulated in Ce-UIO-66 microspheres (Zr-SA/Ce-UIO-66) was prepared and systematically characterized. Its ability for capture of phosphate and glyphosate in their single and binary systems has been investigated comprehensively. Results showed that Zr-SA/Ce-UIO-66 exhibits excellent phosphate adsorption, achieving 92 % removal and a maximum adsorption capacity of 125 mg P/g at 313 K. Diversified mechanisms, including electrostatic attraction, ligand exchange and hydrogen bonding, have cooperatively participated in phosphate removal. Interestingly, in phosphate and glyphosate mixed solutions, the presence of phosphate significantly enhanced the removal of glyphosate for the formation of complexes between phosphate ions and the adsorbent. And that was similar to the presence of glyphosate in phosphate adsorption. Simulated wastewater experiments demonstrated the adsorbent’s practical application in water contaminated with both organic phosphorus and glyphosate composites and its potential for recycling and reuse.
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