SEPARATION AND PURIFICATION TECHNOLOGY
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2021
·
IF 7.312
Xiangjuan Ma,Yan Yan,Qizhou Dai,Jianxian Gao,Shengjue Liu,Yijing Xia
This study focused on the electrochemical oxidation of Acid Blue 9 (AB 9) under direct and pulse current modes using a Ti/SnO 2 -Sb/α,β-Polytetrafluoroethylene-Fe-PbO 2 (PTFE-Fe-PbO 2 ) anode. The results showed that 99.0% of AB 9 and 68.9% of COD could be eliminated at initial pH of 5, initial AB 9 concentration of 100 mg L -1 , pulse frequency of 4000 Hz, current density of 20 mA cm −2 and pulse duty cycle of 50% after 120 min of electrolysis. The pulse electrochemical oxidation of AB 9 at the investigated conditions followed pseudo-first-order kinetics. Compared with the direct current mode, 76.0% of energy consumption could be saved at pulse current mode. The effect of mass transfer and electrode distance on the pulse electrochemical oxidation of AB 9 was also investigated in terms of mass transfer coefficient and effectiveness factor, the results showed that the reduced electrode distance was beneficial to improve the mass transfer and oxidation efficiency, as well as the energy efficiency. LC-MS analysis revealed that benzenesulfonate group, C-N and C-S bonds in AB 9 molecule were initially cleaved under the attack of ⋅OH, then some carboxylic acids were formed and eventually mineralized to CO 2 and H 2 O. Therefore, pulse electrochemical oxidation with a PTFE-Fe-PbO 2 electrode might be a promising alternative to enhance the practicability of electrochemical treatment for dye wastewater.
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MICROCHIMICA ACTA
·
2020
·Vol. 187
·期 10
·1-10
·
IF 6.232
Zhen Deshuai,Shi Sisi,Gao Chan,Kang Qing,Xiao Xilin,Grimes Craig A.,Cai Qingyun
Bi, Fe, and Ti ternary co-doped ZrO 2 (BFT-ZrO 2 ) nanocomposites have been prepared by a sol-gel process and used as both adsorbent and matrix for the enrichment and determination of small molecules by surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF MS). The BFT-ZrO 2 nanocomposites not only can selectively enrich a wide variety of low-mass toxic pollutants but can also be used as an excellent matrix to enhance the laser desorption/ionization efficiency with low background noise and uniform co-crystalline film. Low limits of detection (LODs) (0.1 pg mL −1 for bisphenol A (BPA), 2 pg mL −1 for tetrabromobisphenol A (TBBPA), 0.1 pg mL −1 for alizarin (AZ), 0.001 pg mL −1 for bisphenol S (BPS), 0.01 pg mL −1 for indigo blue (ID), 0.01 pg mL −1 for pentachlorophenol (PCP), 100 pg mL −1 for estradiol (E2), 0.001 pg mL −1 for cetyltrimethylammonium bromide (CTAB), 0.1 pg mL −1 for crystal violet (CV), 1 pg mL −1 for malachite green (MG), 0.01 pg mL −1 for rhodamine B (RhB), and 0.01 pg mL −1 for perfluorooctane sulfonate (PFOS) were achieved. The relative standard deviations (RSDs) of shot-to-shot are 9.4–24% and of sample-to-sample 5.2–17%. The BFT-ZrO 2 matrix was successfully applied to the determination of TBBPA and BPA in tea samples. This method shows a new strategy for determination of toxic compounds in tea.
Graphical abstract
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APPLIED SURFACE SCIENCE
·
2020
·
IF 6.182
Huizhen Deng,Juanjuan Yin,Jinming Ma,Jingxin Zhou,Lexin Zhang,Lili Gao,Tifeng Jiao
A novel catalyst composed of Ag 3 PO 4 bridged by Ni/Ti LDH-graphene heterojunction structure was successfully prepared by a simple in-situ deposition method, which has excellent catalytic performance for 4-NP and 2-NA. Various characterizations to the samples such as XRD, SEM, TEM, STEM-EDS, XPS, TG–DSC, and UV–vis DRS were adopted. Because the ternary structure is mixed with each other to form more heterojunctions and higher specific surface area, the ternary composite Ag 3 PO 4 /Ni-Ti LDH/GO has excellent catalytic and cycle performance. Compared to the precursors Ag 3 PO 4 /GO and Ni-Ti LDH/GO, the finally as-obtained nanocomposite Ag 3 PO 4 /Ni-Ti LDH/GO degraded 4-NP and 2-NA solutions represented more dominant degradation efficiency. In addition, the pseudo-first-order rate constants of the composite catalyst for 4-NP and 2-NA are 0.178 min −1 and 0.089 min −1 , respectively. The complex and irregular surfaces of Ni-Ti LDH/GO provided an ideal carrier with abundant active sites for in-situ depositing and stabilizing of Ag 3 PO 4 NPs, formed the Ag 3 PO 4 /Ni-Ti LDH/GO hybrid possessed an acceptable catalytic performance on the degradation of azo dyes, which could be applied in the efficient treatment of wastewater from industries.
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Molecular Catalysis
·
2020
·
IF 3.687
Yi Yu,Fanfan Li,Zhouxuan Zang,Li Xu,Guoji Liu
Catalytic oxidation of 2-methylnaphthalene to 2-methyl-1,4-naphthoquinone (vitamin K 3 ) is a significant pathway to produce vitamin groups K. High pollution and low-productivity of the traditional method require a greener catalyst and process. In this work, Al/Ti-SBA-15 with different n Si /n Al and n Si /n Ti ratios were hydrothermally prepared in mild acidic condition and tested in partial oxidation of 2-methylnaphthalene. Commercial zeolites NaY, β and ZSM-5 were applied to investigate the influence of mass transfer resistance and acidity on catalytic performance. Catalysts were characterized by XRD, N 2 adsorption-desorption, TEM, NH 3 -TPD, FTIR and Py -FTIR. We have found that the 2-methylnaphthalene conversion and vitamin K 3 selectivity depend strongly on the mesoporous structure as well as Brönsted acid concentration and strength. Irregular micropores and strong acidity will accelerate the cleavage of C = C in aromatic rings, leading to the production of phthalic anhydride. DFT calculation reveals that incorporation of aluminum in SBA-15 can reduce the energy gap, facilitating the electron transfer. And as a consequence of the substitution of Al in tetrahedral positions in SBA-15, Al-SBA-15 (10) gives the best result with 72% yield to vitamin K 3 . This catalyst markedly reduces the activation energy due to the modified activated center. Repeated experiments recommend that Al-SBA-15 is a steady and high-efficiency catalyst for the production of vitamin K 3 .
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CHEMICAL ENGINEERING JOURNAL
·
2019
·
IF 8.355
Zijian Song,Ben Wang,Wu Yang,Tao Chen,Chuan Ma,Lushi Sun
Fe 2.5 M 0.5 O 4 (M = Mn, Ti and Cu) were investigated for the first time as the catalyst for simultaneous removal of NO and SO 2 through catalytic oxidation-absorption with vaporized H 2 O 2 . The physicochemical properties of as-prepared catalysts were comprehensively characterized by XRD, SEM, TEM, BET, XPS, TPR, VSM, TG and PL analyses. Activity test results showed that SO 2 can be completely removed under most conditions. However, NO removal was affected by catalyst, H 2 O 2 consumption, reaction temperature, GHSV and coexistence gases (i.e., H 2 O, O 2 , NO and SO 2 ). Mn, Ti and Cu doping in the magnetite can remarkably enhance NO removal. Redox pairs and oxygen vacancy of catalysts were considered as vital factors affecting OH generation. Base on the catalyst characterization and DFT calculation results, the main mechanism of Mn, Ti and Cu doping on the catalytic activity improvement was explained as follows: (a) Mn, Ti and Cu doping can increase the catalyst surface area; (b) Ti on the surface can directly promote the catalytic decomposition of H 2 O 2 ; and (c) Mn and Cu doping can promote the generation of oxygen vacancy and indirectly increase the activity. Moreover, two arrangement forms of an industrial simultaneous removal system for NO, SO 2 and Hg 0 were proposed.
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CHEMICAL ENGINEERING JOURNAL
·
2022
·
IF 16.744
Ji Shu,Kanming Wang,Virender K. Sharma,Xiping Xu,Nasri Nesnas,Hongyu Wang
This paper presents Fe(VI) combined with Ti/Zn layered double hydroxide (Fe(VI)-Ti/Zn LDH) as a composite to degrade organic pollutants (pesticides and pharmaceuticals) under visible light (VL). The Fe(VI)-LDH/VL system was shown to effectively activate Fe(VI) and simultaneously enhance separation and migration of electrons-holes on the Ti/Zn LDH surface. Furthermore, the Fe(III) particles resulting from the Fe(VI) reduction were adsorbed and coordinated onto the LDH surface to form an in-situ heterojunction photocatalyst which narrowed the wide bandgap from 3.08 eV to 1.44 eV of the LDH and achieved further oxidation of pollutants. Detailed kinetic and mechanistic investigations using the pesticide, imidacloprid (IMI), revealed multi-oxidant intermediate species (Fe V /Fe IV , OH, h VB + and O 2 − ) involved in degrading the parent micropollutant and yielding oxidized products. This study also assessed the application of Fe(VI)-Ti/Zn LDH composite to other pesticides and pharmaceuticals (carbaryl (CAB) and metribuzin (MBZ), trimethoprim (TMP) and carbamazepine (CBZ)), and exhibited satisfactory micropollutants removal. The newly reported VL-induced Fe(VI) activation system, based on Fe(VI)-Ti/Zn LDH composite, may be an effective multi-oxidant strategy to oxidize pollutants in water.
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CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Sheng Pang,Liangwei Cong,Youpeng Xu,Yiwei Sun,Dong Wang,Guoyu Qian,Zhi Wang
Typically, the X-ray diffraction spectrum of a highly oriented structure (HOS) MAX phase displays a prominent (002) characteristic peak. Surprisingly, this principle does not hold true for Ti 2 SC. Instead, the synthesized Ti 2 SC consistently exhibits a polyhedral structure (PS). Furthermore, even with hot-pressing sintering, the purity of Ti 2 SC remains relatively low. The primary factors contributing to anomalous crystal structures and low purity are insufficient crystal growth and limited reactant contact. In this study, we successfully achieved dual regulation of the crystal structure and purity of Ti 2 SC within the Ti/TiC/FeS 2 system, which was accomplished by enhancing reactant contact and controlling the growth rates of crystal planes. Notably, the intermediate products FeS and Fe, existing in a liquid phase at varying temperatures, played a crucial role in both the formation of Ti 2 SC and the growth of Ti 2 SC crystals. As a result, PS-Ti 2 SC and HOS–Ti 2 SC with purity greater than 99 wt% were successfully prepared. The formation of PS-Ti 2 SC can be attributed to the inadequate growth of each crystal plane at relatively lower temperatures (1500 °C). While the synthesis of HOS–Ti 2 SC necessitates the utilization of both a liquid phase and high temperature, as the epitaxial growth mechanism followed by vertical growth has been demonstrated to facilitate the generation of highly oriented crystals. The liquid phase facilitates the swift growth of Ti 2 SC crystals along the (001) crystal plane, while the (002) crystal plane necessitates a higher temperature (1760 °C) for relatively rapid growth. This work will open a new pathway for the development of the MAX phase from the perspective of crystal structure regulation and high purification preparation.
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ELECTROCHIMICA ACTA
·
2015
·
IF 4.504
Li Xu,Xiaoliang Song
A novel antimony-doped tin oxide nanoparticles electrode (Ti/ATONPs) was fabricated by screen printing method, which was applied in wastewater treatment area for the first time. In contrast with traditional Ti/SnO 2 -Sb electrode prepared by electrodeposition , Ti/ATONPs electrode possessed smaller grains and crystallite size, remarkable porous structure with 39.9 m 2 g −1 surface area and 3.0 nm average pore size as seen by Scanning electron microscopy (SEM), X-ray diffraction (XRD) Brunauer-Emmett-Teller (BET). Electrochemical measurements including linear sweep voltammetry (LSV), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and chronocoulometry (CC) were employed to investigate the electrochemical activity, compared with Ti/SnO 2 -Sb, Ti/ATONPs owned a higher oxygen evolution potential (2.18 V versus 2.08 V), a lower charge transfer resistance (0.47 Ω versus 13.24 Ω), a larger electrochemically effective surface area (38.97 cm 2 cm −2 versus 3.03 cm 2 cm −2 ) and the voltammetric charge analysis indicated that Ti/ATONPs could create more reaction active sites to enhance the electrocatalytic efficiency. To further explore the electrocatalytic oxidation performance, AR 73 was used as target pollutant to monitor the concentration changes with time through UV/vis spectroscopy, the removal of AR 73 degradation and corresponding kinetic constant of Ti/ATONPs electrode was 83.9%, 0.62 h −1 while that of Ti/SnO 2 -Sb was 65.8%, 0.40 h −1 respectively. These results show that Ti/ATONPs electrode prepared by screen printing method may become a promising electrode in treating wastewater.
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APPLIED CATALYSIS B-ENVIRONMENTAL
·
2025
·
IF 21.1
Mazhar Khan,Zeeshan Akmal,Muhammad Tayyab,Seemal Mansoor,Dongni Liu,Ziwei Ye,Jinlong Zhang,Shiqun Wu,Lingzhi Wang
The rational design of heterojunction photocatalysts is crucial for enhancing CO 2 photoreduction efficiency, yet precisely channeling photogenerated electrons to the CO 2 adsorption sites remains an enormous challenge. In this work, we developed an organic-inorganic heterostructure with continuous inter- and intra-component electric fields. The integration of BiOBr with MIL-125 via chemical bonding established a heterojunction, where the built-in electric field between the two components facilitated the efficient transfer of photogenerated electrons from BiOBr to MIL-125. The intrinsic electric field of MIL-125 further drove the accumulation of photogenerated electrons at Ti sites. This tandem electric field effect, in conjunction with the CO 2 adsorption and activation at Ti sites, significantly enhanced the efficiency of CO 2 reduction within the heterojunction system. The optimized photocatalyst achieving CO production at a rate of 65.6 μmol g −1 h −1 with nearly 90 % selectivity without the use of sacrificial agents, exhibiting a remarkable 43-fold and 8-fold enhancement in activity compared to pristine MIL-125 and BiOBr, respectively. In-situ infrared spectroscopy and theoretical calculations confirmed the energy optimization effect of the heterostructure on CO 2 activation and the hydrogenation reaction, facilitating the formation of the key intermediate *COOH. This work elucidates the mechanism by which tandem built-in electric fields facilitate charge separation.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2024
·
IF 9.4
Jiangwen Xu,Jinxu Song,Haotian Li,Hui Song,Zicong Yang,Yukun Chang,Wenyuan Zhou,Jinshu Wang,Hongyi Li
The chlorine evolution reaction (CER) is essential for chlorine (Cl 2 ) production. However, the catalyst deactivation and side reaction oxygen evolution reaction (OER) are still serious problems for CER. Improving the stability and selectivity of catalyst for long term electrocatalytic reaction in large current density is highly desired. In this work, a self-supporting Ti/RuO 2 @TiO 2 nanotubes (NTs) electrode had been developed by co-sputtering titanium (Ti) and ruthenium oxide (RuO 2 ) onto the high-ordered titanium dioxide (TiO 2 ) nanotubes substrate. This process produced a well-distributed incorporation of Ti species within the RuO 2 coating. It has revealed that the presence of Ti element optimizes the surface morphology of electrode and modulates the electronic state of ruthenium (Ru) species, effectively preventing over-oxidation and thereby enhancing stability. The Ti/RuO 2 @TiO 2 NTs self-supporting electrode exhibits remarkable electrocatalytic activity for CER, evaluated by lower overpotential (58 mV) at 10 mA cm −2 and reduced Tafel slope (78 mV dec −1 ) than that of other electrodes. Moreover, its mass activity achieving 478 mA mg Ru −1 at 1.3 V (vs SCE) is 4.3 times that of commercial dimensionally stable anodes (DSA). After operating for approximately 150 h at 100 mA cm −2 , the electrode exhibits minimal performance degradation, underscoring its exceptional stability. Additionally, the large potential difference between CER and OER makes it maintain high Cl 2 selectivity, achieving up to 91 % across varying current densities and reaction times. This work provides valuable strategy for designing novel Ru-based catalysts for practical CER applications in seawater and industrial environments.
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CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Yuanyuan Cong,Mengling Liu,Luyun Chen,Yurong Qi,Limin Zhang,Qiuping Zhao,Chunlei Li,Haibin Wang
The sluggish hydrogen energy conversion kinetics in alkaline medium and the complete passivation under high anodic potential as well as the easy detachment of active sites from the carbon substrate are three critical challenges of Ru-based electrocatalysts for their practical application. Herein, Ru (single atoms and nanoclusters)-embedded TiO 2-x (Ru SA -Ru NC /TiO 2-x ) well solves above-mentioned urgent problems simultaneously. Specifically, the optimal Ru SA -Ru NC /TiO 2-x electrocatalyst delivers a mass activity of 1620 A g Ru –1 and a low overpotential of 24 mV at 10 mA cm −2 in alkaline hydrogen oxidation and evolution reactions (HOR/HER), respectively. More importantly, the Ru/TiO 2-x can unprecedentedly catalyze the HOR up to a potential of 1.2 V vs. RHE without deactivation and almost maintain unchanged after accelerated stability tests of 10,000 CVs or the presence of 100 ppm CO impurity. Confirmed by in/ex-situ experimental measurements and computational analyses, the enhancement in performance is attributed mainly to the construction of high-density Ru-Ti bonds, maintaining the unblocked charge transfer from TiO 2 to Ru and achieving more low-valence Ru species. The observed Ti 3+ species on oxygen vacancies derived from the original structure and in-situ formation during the electrochemical reaction would be preferentially oxidized, further protecting Ru sites and aiding in the electrocatalytic process. Benefiting from Ru-Ti bonds and triggered oxygen vacancies, Ru could serve as exclusive optimal H adsorption sites and cooperate with the OH ad on Ti sites, rapidly and stably accelerating hydrogen energy conversion.
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JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2019
·Vol. 103
·期 2
·1018-1026
·
IF 3.094
Xuefang Luo,Ziyang Hou,Tianliang Zhou,Rong-Jun Xie
Mn 4+ -activated fluoride red-emitting narrow-band phosphors have been successfully used in wide color-gamut white LEDs for liquid crystal display (LCD) backlights. However, highly concentrated and toxic HF is usually used in their synthesis, causing environment and safety issues. In this work, we proposed a HF-free green method, that is, using NH 4 F/HCl instead of HF, to synthesize a series of A 2 X F 6 :Mn 4+ ( A = K, Na, Rb, Cs; X = Si, Ge, Ti) phosphors. The microstructure, photoluminescence (PL) properties, thermal quenching, and applications of the synthesized phosphors were investigated. Using the proposed approach, the phosphors generally showed a pure phase, a particle size ranging from 5 to 45 μm, and some characteristic sharp emission lines of Mn 4+ in the red spectral range. The internal quantum efficiency was varied in a broad range of 69%-94% under the 460 nm excitation, depending on the composition of the fluoride host. Among these compositions, K 2 X F 6 :Mn 4+ ( X = Ge and Ti) phosphors even had a similar external quantum efficiency (>60%) with commercial ones. By combining K 2 GeF 6 :Mn 4+ (narrow-band red) and β -sialon:Eu 2+ (narrow-band green) with a blue LED, a white light-emitting diode (wLED) backlight with a color gamut of 87.7% National Television System Committee Standard, color temperature of 8423 K, and a luminous efficacy of 110.8 lm/W was demonstrated. These results indicate that the synthetic method proposed in this work is universal for preparing highly efficient fluoride phosphors used in wLEDs.
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