JOURNAL OF HAZARDOUS MATERIALS
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2018
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IF 6.434
Yangchun Leng,Qintang Li,Qiang Tian,Xiaoyuan Chen,László Almásy,Yuliang Liu,Guangai Sun,Xianguo Tuo,Minhao Yan,Mark J. Henderson
The ability of bentonite and montmorillonite pillared by Al-oxide and mixed (Ln-Al)-oxides (Ln = La, Ce) to remove 239 plutonium solution species from water is comparatively investigated at pH 7 and pH 4. Small-angle scattering and neutron contrast variation with H 2 O/D 2 O mixtures is used to verify the ingress of water in the calcined products after hydrophilicity was introduced by an NH 3 -H 2 O vapor treatment. The size and shape of the (La/Ce)-Al oxo-hydroxy pillaring cations (2 nm spheres) is determined by small-angle x-ray scattering from the pillaring solutions. Not all of the oxide pillars improved Pu uptake compared with sodium montmorillonite. At neutral and acidic pH only (Ce-Al)-oxide pillared clays showed the ability to remove Pu over the concentration range studied (1.35 × 10 −8 –8 × 10 −8 mol dm −3 ) with distribution coefficient ( K D ) values >10 4 . XPS analysis of the (Ce-Al)-oxide pillared clays indicates the presence of Ce 4+ as cerium dioxide. The progressive improvement in sorption performance in the order of pillar type Al 2 O 3 < La 2 O 3 -Al 2 O 3 << CeO 2 -Al 2 O 3 reflects the increasing access of Pu solution species to the clay mineral layers by changes to the basal spacing and specific surface area, and also to the higher stability of the (Ce-Al)-oxide pillars.
研究领域:
环境科学
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材料科学
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高影响因子
Catalysts
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2020
·Vol. 10
·期 11
·1329
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IF 3.52
Shijie Hao,Yandi Cai,Chuanzhi Sun,Jingfang Sun,Changjin Tang,Lin Dong
Monolithic Mn-Fe-Ce-Al-O catalyst with honeycomb cordierite ceramic as a carrier was reported for the first time for low temperature deNOxapplication. In the reaction of selective catalytic reduction (SCR) of NO with NH3, a NO conversion of above 80% at 100 °C was obtained. Notably, the catalyst also showed excellent resistance against SO2and H2O. About 60% NO conversion was maintained after successive operation in the mixed stream of SO2and H2O for 168 h. The Brunner−Emmet−Teller (BET) measurement, SEM, EDS, thermogravimetric analysis (TG), FT-IR, and XPS results of the used catalysts indicated that certain amounts of ammonium sulfate was formed on the surface of the catalyst. XPS results revealed that partial of Fe2+was oxidized to Fe3+during the reaction process, and Fe2+species have strong redox ability, which can explain the decrease in activity after reaction. In addition, SO2and H2O induced a transformation of Ce from Ce4+to Ce3+on the surface of the catalyst, which increased the amount of chemisorbed oxygen. Owing to these factors, the addition of Ce and Fe species contributes to excellent resistance of the catalyst to SO2and H2O.Keywords:honeycomb catalyst;Mn-Fe-Ce-Al-O;low temperature denitration;water and sulfur resistance
研究领域:
环境科学
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催化化学
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DOI
高影响因子
Catalysts
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2018
·Vol. 8
·期 12
·642
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IF 3.465
Yan Gao,Tao Luan,Mingyang Zhang,Wenke Zhang,Wenchen Feng
A series of Mn−Fe−Ce−Ox/γ-Al2O3nanocatalysts were synthesized with different Mn/Fe ratios for the catalytic oxidation of NO into NO2and the catalytic elimination of NOxvia fast selective catalytic reduction (SCR) reaction. The effects of Mn/Fe ratio on the physicochemical properties of the samples were analyzed by means of various techniques including N2adsorption, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), H2-temperature-programmed reduction (TPR), NH3-temperature-programmed desorption (TPD) and NO-TPD, meanwhile, their catalytic performance was also evaluated and compared. Multiple characterizations revealed that the catalytic performance was highly dependent on the phase composition. The Mn15Fe15−Ce/Al sample with the Mn/Fe molar ratio of 1.0 presented the optimal structure characteristic among all tested samples, with the largest surface area, increased active components distributions, the reduced crystallinity and diminished particle sizes. In the meantime, the ratios of Mn4+/Mnn+, Fe2+/Fen+and Ce3+/Cen+in Mn15Fe15−Ce/Al samples were improved, which could enhance the redox capacity and increase the quantity of chemisorbed oxygen and oxygen vacancy, thus facilitating NO oxidation into NO2and eventually promoting the fast SCR reaction. In accord with the structure results, the Mn15Fe15−Ce/Al sample exhibited the highest NO oxidation rate of 64.2% at 350 °C and the broadest temperature window of 75–350 °C with the NOxconversion >90%. Based on the structure–activity relationship discussion, the catalytic mechanism over the Mn−Fe−Ce ternary components supported byγ-Al2O3were proposed. Overall, it was believed that the optimization of Mn/Fe ratio in Mn−Fe−Ce/Al nanocatalyst was an extremely effective method to improve the structure–activity relationships for NO pre-oxidation and the fast SCR reaction.
研究领域:
环境科学
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催化化学
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DOI
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
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2024
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IF 4.8
Junxue Li,Lingyi Li,Shengnan Zhang,Wei Cheng
In addressing eutrophication resulting from phosphate accumulation, multi-metallic oxides often outperform single-metallic oxides in phosphate adsorption capacity. While alumina is abundant, its stability in acidic or alkaline environments is limited. Contrastingly, zirconium and cerium oxides demonstrate superior acid and base resistance, alongside specific phosphate affinity. This study focuses on the synthesis of Zr-Al and Ce-Al binary oxide nanoparticles through a sol-gel approach for phosphate removal from aqueous solutions, evaluating their efficiency through batch experiments. By judiciously adjusting the Zr/Al and Ce/Al ratios, binary oxide nanoparticles with distinct structures, grain sizes, surface characteristics, and phosphate adsorption properties were fabricated. Results indicate that Zr(3)Al(10) and Ce(3)Al(10) nanoparticles exhibit optimal phosphate adsorption properties among Zr-Al binary oxide variants and Ce-Al binary oxide counterparts, respectively. Kinetic data conform to the pseudo-second-order model for phosphate adsorption on Zr(3)Al(10) and Ce(3)Al(10), while equilibrium adsorption isotherms align with the Langmuir model. Phosphate adsorption capacities reached 83 mg/g for Zr(3)Al(10) and 210 mg/g for Ce(3)Al(10), positioning them as potent adsorbents. Coexisting anions minimally influence phosphate adsorption on Zr(3)Al(10) and Ce(3)Al(10) nanoparticles, indicating high selectivity towards phosphate, whereas Ca 2+ and Mg 2+ ions notably enhance phosphate adsorption. Mechanistically, phosphate adsorption on both nanoparticles follows electrostatic attraction, ligand exchange, and inner-sphere complexation, with surface-OH groups playing a pivotal role. Leveraging the advantageous properties of their parent materials, Zr-Al and Ce-Al binary oxide adsorbents exhibit synergistic effects, enhancing their potential for phosphate removal.
研究领域:
环境科学
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材料科学
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DOI
高影响因子
JOURNAL OF CATALYSIS
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2026
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IF 6
Xiangwei Ren,Yue Zhang,Shuzhen Lyu,Li Wang,Ruichen Liu,Guozhu Liu,Rongrong Zhang
Oxidation of methylene compounds remains a critical challenge due to the difficult activation of C–H bond. Herein, Ce–Al composite oxide was prepared and employed for oxidation of 2-alkyl-anthrone and anthracene to corresponding anthraquinone (AQ) which is used widely in the H 2 O 2 production by the anthraquinone process and fine chemical industries, with air at mild conditions. Characterization results show that incorporation of Ce, existing partially in CeAlO 3 phase, results in the generation of oxygen vacancies and enhancement of reducibility. The optimal Ce–Al composite oxide (10%CeAl) exhibits superior performance in oxidation of 2-alkyl-anthrone and anthracene to AQ. The conversion of 100% could be achieved for 2-alkyl-anthrone to AQ at reaction time of 8 h and for 2-alkyl-anthracene to AQ at 15 h over 10%CeAl, with 100% selectivity. In-situ electron paramagnetic resonance measurements and DFT calculations reveal that the Ce–O–Al structure in CeAlO 3 phase promotes the formation of carbon-centered radical R • through altering the C–H cleavage mechanism from hydrogen atom transfer to proton-coupled electron transfer (PCET), and superoxide anion radicals (O 2 •− ) formed on oxygen vacancies promote oxidation of R • .
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高影响因子
Nanomaterials
·
2026
·Vol. 16
·期 16
·1015
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IF 4.8
Xin Lin,Jiayi Tu,Jinyun Zhao,Fangfang Wu,Xingping Fu,Hao Lin,Jiapeng Hu
In this study, a hierarchical rod-assembled, polypyrrole-modified Ce–Al–La trimetallic metal–organic framework (Ce–Al–La–MOFs@PPy) composite was successfully synthesized through a solvothermal method combined with in situ polymerization for efficient fluoride removal from aqueous solutions. The incorporation of conductive polypyrrole (PPy) into the multimetallic MOFs effectively enhanced the structural stability, surface properties, and adsorption performance of the material. Adsorption experiments demonstrated that the optimal metal-to-ligand molar ratio was 3:1, and the prepared adsorbent exhibited excellent fluoride removal performance under weakly acidic conditions (pH = 5). The maximum adsorption capacity calculated from the Langmuir model reached 216.92 mg·g−1at 45 °C. Adsorption kinetics were well fitted by the pseudo-second-order model, indicating that the adsorption process was mainly governed by chemisorption. Mechanism investigations based on FTIR and XPS analyses demonstrated that fluoride removal mainly occurred through electrostatic attraction and coordination exchange between fluoride ions and the Ce/La active sites. In addition, the composite exhibited good selectivity, anti-interference ability toward coexisting ions, and satisfactory fluoride removal performance in practical industrial wastewater. These findings suggest that Ce–Al–La–MOFs@PPy is a promising adsorbent for efficient fluoride-contaminated wastewater treatment.
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高影响因子
FUEL
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2024
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IF 6.7
Ranlei Shao,Lu Zhang,Luyuan Wang,Jianmei Wang,Xingyu Zhang,Shiwang Han,Xingxing Cheng,Zhiqiang Wang
In this study, Ru catalysts supported on Ce-Al composite carriers were prepared using the precipitation-hydrothermal method, significantly enhancing ammonia decomposition efficiency. The test results show that the Ru/3Ce-Al catalyst, with a Ru loading of only 0.8 wt%, achieves a reaction rate of 14.17 mmol g cat −1 min −1 at 500 °C, and reaches a 95 % conversion rate at 525 °C. No decline in efficiency was observed after 48 h of durability testing, which significantly reduces the usage of Ru. The RuO 2 particle size in the samples was only 2–4 nm. Ce-Al composite increased the specific surface area and pore volume of the catalyst, facilitating the uniform distribution of Ru. Additionally, it increased the number of surface acidic sites and strengthened the metal-support interaction. The unique low redox potential and oxygen vacancies of CeO 2 allowed for faster electron transfer to the Ru surface. DFT calculations revealed that bridge site adsorption was more stable, with the rate-determining step of the ammonia decomposition reaction being the formation of N 2 . Ce-Al composite catalysts enhanced NH 3 adsorption strength and lowered the reaction energy barrier.
研究领域:
催化化学
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材料科学
·
理论计算
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DOI
高影响因子
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