Journal of the American Chemical Society
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2024
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IF 14.4
Xuannuo Yi,Shasha Liu,Taotao Zhao,Xiangke Guo,Kai Zhou,Weiping Ding,Wei Wang
Zeolites are essential solid acid catalysts in various chemical processes. Temperature-programmed desorption (TPD) is one of the most established techniques used to characterize the acidity of zeolites by measuring the desorption kinetics of probes from bulk samples. However, conventional TPD can hardly deliver the intrinsic acid properties of zeolites because the apparent desorption kinetics are inevitably mixed with mass transfer and thermal conduction due to the large sample amount (∼0.1 g). Herein, we developed an optical microscopy approach to measure the TPD spectra of single zeolite nanoparticles, termed oTPD, by in situ monitoring of the reduced scattering intensity of individuals as a result of the desorption of probe molecules during heating. A significantly reduced sample amount contributed to the oTPD spectrum, revealing an intrinsic desorption temperature of ∼300 °C lower than the apparent value and also a greatly narrowed peak width from ∼150 to ∼15 °C. Correlating oTPD and micro-Raman spectra of the very same individuals further uncovered a linear dependence between the acidity and the content of silicon islands. This study provided unprecedented capabilities for measuring the intrinsic acid properties and the desorption kinetics of single zeolite nanoparticles, with implications for better understanding the structure–acidity relationship and for designing better zeolite catalysts.
研究领域:
化学工程
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催化科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF MEMBRANE SCIENCE
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2022
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IF 10.53
Ronghua Ma,Xiaolong Lu,Shaozhe Zhang,Kai Ren,Jie Gu,Chao Liu,Ziqiang Liu,Hanli Wang
In recent years, membrane separation technology has been widely used in various fields. And for the increasingly severe oily wastewater system, there is an increasing demand for the anti-fouling properties of the membranes. Based on the concept of fluorine-free, non-toxic, environmental-friendly and low-cost, this study constructed a discontinuous silicon-island structure with low surface energy on the surface of the hydrophilic membrane, which endows the PVDF-CTFE membrane with fouling resistance and cleaning pH-responsiveness. The discontinuous silicon-island structures were constructed by introducing SiO 2 nanoparticles on the super-hydrophilic layer of the PVDF-CTFE membrane modified by itaconic acid, and then hydrophobically treated with polydimethylsiloxane (PDMS). The experimental results exhibited that the modified membrane reached the hydrophobic and underwater super-oleophobic state when treated by PDMS for 1.0 h. The water contact angle (WCA) and the underwater oil contact angle (OCA) were 124° and 151°, respectively. Furthermore, the water flux remained at 186 L m −2 h −1 with no serious pore-plugging. Moreover, the water flux decay rate (FDR) remained below 19.6%, when modified membrane treating soybean oil/water emulsion for 6 cycles, presenting an excellent anti-fouling performance. Additionally, the water flux recovery rate (FRR) was over 99.3% after alkali cleaning, indicating the modified membrane possessed excellent cleaning pH-responsiveness. The above analysis exhibited that the synergistic effect of hydrophilic micro-domains and oleophobic micro-domains not only slows down the attachment of hydrophobic pollutants but also promotes the separation of hydrophobic pollutants during chemical cleaning, which greatly improves its anti-fouling performance and expands its application prospect.
研究领域:
材料科学
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环境工程
✓ 已验证
产品关联
DOI
高影响因子
INORGANIC CHEMISTRY
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2024
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IF 4.3
Runyu Ma,Yida Zhou,Huifang Wu,Jincong Wang,Xin Yan,Wei Huang,Tianlong Wang,Shutao Xu,Limin Ren
SAPO-37 molecular sieve, characterized by its three-dimensional 12-membered-ring FAU structure, has drawn wide attention due to its unique properties and catalytic potential. However, its susceptibility to framework collapse under low-temperature and humid conditions hinders practical applications, affecting both the reaction performance and sample storage. To tackle this, we utilized aluminum phosphate as a precursor for synthesizing SAPO-37, aiming to modify Si incorporation mechanisms and improve P and Al environments. Solid NMR spectroscopy combined with other techniques proves that the resulting SAPO-37-AP has enriched silicon islands, leading to reduced water adsorption, more reversible structural change, and significantly enhanced stability after low-temperature vapor treatment compared to conventional SAPO-37. Remarkably, SAPO-37-AP, after water vapor treatment, still exhibits superior performance in the liquid-phase Beckmann rearrangement reaction. This approach enhances stability, reduces templating agent amounts, and improves the solid product yield, offering promising practical applications.
研究领域:
材料科学
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催化化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
DESALINATION
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2025
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IF 9.8
Ronghua Ma,Xiaolong Lu,Jie Gu,Kai Ren,Yuling Ren,Yuefei Song,Zhong Ma
With a high rejection rate for salts and non-volatile organic compounds, membrane distillation (MD) is widely used in in the treatment of hypersaline wastewater. However, the performance degradation of membranes caused by pore-wetting, mineral scaling or structural instability greatly limits their development potential. Improving the durability of service performance in MD process has become the focus of the scientific community. Herein, we anchored the fluor‑silicon island structure with low-surface-energy onto the poly(vinylidene fluoride- co -chlorotrifluoroethylene) (PVDF-CTFE) membrane surface by covalent bonding based on C Cl, so as to construct an omniphobic membrane with excellent anti-fouling and anti-wetting performance. Through the characterization of the surface morphology, element composition and basic physicochemical properties of the membrane, it was demonstrated that the discontinuous island-structure was successfully anchored on the membrane surface through chemical bonds, endowing the modified membrane with a higher gas-permeability coefficient and liquid entry pressure (LEP w > 4.0 bar), and exhibiting outstanding gas-permeability and water-impermeability. Meanwhile, it has a high contact angle for water (154.0°), brine (152.2°), Sodium Dodecyl Sulfonate (SDS) salt solution (150.5°), and soybean oil emulsion (123.1°), showing excellent lyophobic properties. Experimentally, it was demonstrated that the modified membrane had higher vapor-flux (≥ 23.0 kg m −2 h −1 ), lower irreversible flux decay rate (< 8.8 %), and could be continuously and stably operated for 60 h with excellent performance compared with the original membrane, homogeneous coating or electrostatic adsorption modified membranes. Treating hypersaline wastewater with complex components, it still exhibits excellent stability, anti-wetting, and anti-fouling performance after long-term operation.
研究领域:
环境工程
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膜科学
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材料科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）