MONATSHEFTE FUR CHEMIE
·
2019
·Vol. 150
·期 7
·1349-1354
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IF 1.501
Li Yunhao,Liu Shiquan
Abstract A porous silica gel with both COOH and NH 2 groups was synthesized in one pot by the addition of l -glutamic acid ( l -GA) into a synthesis medium consisting of tetraethyl orthosilicate, water, ethanol, and 1-butylamine. The inclusion of l -GA in the as-synthesized product ( l -GA-SiO 2 ) was evidenced by FT-IR and TG measurements. The l -GA was chemically bonded with silica as indicated by the shift of FT-IR bands at 1510 and 1400 cm −1 in the spectrum of l -GA to higher wavenumbers of 1540 and 1460 cm −1 in the one of l -GA-SiO 2 . The TG analysis showed that the l -GA-SiO 2 had an increase of weight loss by 5.6% due to the decomposition of the included l -GA which was centered at around 313 °C, suggested by a new peak in the DTG curve. Compared with the one synthesized without l -GA, the l -GA-SiO 2 was more aggregated with smaller surface area. However, the latter showed a higher removal efficiency by 17.1% toward zinc ions in water than the former and the adsorbed ions were hardly released again into water from the used adsorbent. Graphical abstract
研究领域:
材料科学
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环境科学
·
化学工程
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DOI
高影响因子
Materials
·
2021
·Vol. 14
·期 3
·577
·
IF 3.623
Shaokun Hao,Chuanshuang Hu,Xiuyi Lin,Jin Gu,Hong Yun,Weiwei Zhang
Complexation copper with amine provides an effective strategy for fixation copper in wood, while hydrophobic modification improves the dimensional stability of wood. Thus, a combination of complexation and hydrophobization is expected to enhance the efficiency of copper-based biocides. In this study, hydrophobic hybrid silica gel containing copper amine complexes (MACu) was prepared through an in situ sol-gel process in wood using methyltriethoxysilane (MTES), 3-amino-propyltriethoxysilane (APTES), and copper chloride. The resistance to growth of molds for MACu modified wood (Populus tomentosa) was measured according to ASTM D3273-16. A leaching resistance test was carried out in accordance with AWPA E11-16. The results showed that onlyAspergillus nigercovered the surface of untreated wood blocks and no mold grew on the MACu surface even after the leaching test. MACu xerogel and MACu wood were further characterized by SEM-EDS, FTIR, and XPS. A possible schematic diagram of the reaction mechanism was proposed to explain the high-efficiency anti-mold performance of MACu wood.
研究领域:
材料科学
·
微生物学
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DOI
高影响因子
THERMOCHIMICA ACTA
·
2017
·
IF 2.236
Fang Tian,Shiqi Zhang,Min Zhai,Jian Sui,Xiaozheng Lan,Jigang Gao
Polyethylene glycols (PEG, average molecular weight 2000, and 10,000) are embedded in silica gels (SG) with pore diameters of d = 10–200 nm. The PEG/SG composites were analyzed using differential scanning calorimetry (DSC), scanning electron microscope (SEM) and powder X-ray diffractions (XRD). Inside the nanopores, melting temperatures of the PEG and the depression of the melting points, have linear relation with the reverse pore size. The latent heat is reduced with the decreasing pore size. The composites remained no leakage of PEG above the melting point in pore fillingness of 80%. In a short-term thermal cycling, the composites display stable melting points and heat storage capacities. The diffractions of PEG in the pores show the same patterns with the bulk, revealing a same structure basis with good heat storage performance. The nano-sized PEG act as a series of new phase change materials obtained by adjusting the size.
研究领域:
材料科学
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热能工程
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化学工程
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DOI
高影响因子
POLYMER ENGINEERING AND SCIENCE
·
2017
·Vol. 58
·期 8
·1381-1390
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IF 1.449
Xianyuan Gu,Ni Li,Jin Cao,Jie Xiong
The polyurethane (PU)/hydrophobic silica gel (HSG) fibrous membranes with the hydrophobic and breathable surface was fabricated via electrospinning. By employing the HSG incorporation, mechanical properties, thermal stability, and waterproofness of the composite membranes could be improved. The porous structure of the membranes would be regulated by tuning the temperatures of thermal treatment. When HSG content increased to 3 wt%, the PU/HSG composite membranes possessed remarkable tensile strength of 6.3 MPa and high water contact angle (WCA) of 134°. Furthermore, the maximum WCA (142° ± 1°), good hydrostatic pressure (5.45 kPa), large water vapor transmission rate (8.05 kg/m 2 /day), and high air permeability (9.25 L/m 2 /s) of the composite membranes could be achieved by heat treatment at 120°C. The resultant membranes performed significantly better when compared to the pure PU membranes under the same conditions, such as the higher tensile strength (100%), better waterproofness (200%), and stronger breathablity (25%). POLYM. ENG. SCI., 58:1381–1390, 2018. © 2017 Society of Plastics Engineers
研究领域:
材料科学
·
纺织工程
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产品关联
DOI
高影响因子
JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY
·
2019
·Vol. 321
·期 2
·733-745
·
IF 1.186
Hu Peizhuo,Nan Yu,Tai Wenya,Shan Qiang,Zhong Yi,Lei Zhiwei,Liu Tonghuan,Chen Suwen,Qian Lijuan
Modification of silica gel by butanedioic anhydride (SiO 2 –BDAH) results in efficient adsorbents for removal of U(VI), Th(IV), and Eu(III) from aqueous solutions. SiO 2 –BDAH was characterized by Fourier Transform infrared spectroscopy, elemental analysis, N 2 adsorption–desorption isotherms, thermogravimetic analysis, and potentiometric titration. The effect of contact time, pH, and initial concentration of radioactive solutions and temperature on the adsorption capacity of the sorbent was investigated. The sorption equilibrium times of U(VI), Th(IV), and Eu(III) onto SiO 2 –BDAH were 1.5, 2, and about 10 h. The sorption percentages of U(VI), Th(IV), and Eu(III) increased with increased pH from 1 to 5. The sorption process of U(VI), Th(IV), and Eu(III) can be described by the Langmuir model, with sorption capacities of 5.10 × 10 −5 , 5.06 × 10 −5 , and 3.44 × 10 −5 mol/L, respectively. The enthalpy and entropy changes were all positive, whereas the free energy changes were negative. This study indicated that SiO 2 –BDAH can remove U(VI) and Th(IV) at the same time in the presence of multiple ions from waste water quickly.
研究领域:
环境科学
·
放射化学
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产品关联
DOI
高影响因子
AICHE JOURNAL
·
2018
·Vol. 64
·期 11
·4027-4038
·
IF 3.326
Hui Sun,Zhongwei Sun,Benxian Shen,Jichang Liu,Gengnan Li,Di Wu,Yuxin Zhang
One-pot synthesis route was explored for preparing binderless zeolite A via an in situ hydrothermal transformation process involving the preformation of silica gel precursors. Synthesis process was optimized and resulting samples were characterized using XRD, Raman spectroscopy, EDS, 29 Si and 27 Al NMR spectroscopy, SEM, HRTEM, and pore structure analyses. Furthermore, the kinetics for the in situ synthesis was investigated and the underlying crystallization mechanism was interpreted. The transformation of silica precursors was accomplished via controlling the synthesis parameters which govern the crystallization through determining the dissolution rate of silica nanoparticles, diffusion of Al species into silica precursors and crystal nuclei growth. Subsequently, Al species could contact and react with released Si species from silica nanoparticles to build the structural units that finally construct the LTA framework through self-organized arrangement. On pure zeolite A phase basis, the synthesized binderless sample exhibits higher specific surface area and n-paraffins adsorption capacity than binder-containing zeolite. © 2018 American Institute of Chemical Engineers AIChE J , 64: 4027–4038, 2018
研究领域:
材料科学
·
化学工程
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产品关联
DOI
高影响因子
DYES AND PIGMENTS
·
2023
·
IF 4.5
Taisheng Wang,Yifan Wu,Yangguang Xia,Ye Yuan,Ziyi Dou,Chenqun Kan,Na Zhang
We have synthesized a kind of cyano-substituted oligo( p -phenylene) hybrid materials by Knoevenagel condensation reaction, which can be used as ratiometric relative humidity (RH) sensor. When the RH increased from 5 % to 90 %, the maximum emission peak of C1-3/SG gradually redshifted from 530 nm to 575 nm with the fluorescence changed from green to orange. This phenomenon can be attributed to the water vapor induced aggregation of dyes on the matrix. The non-covalent force between the dyes and the silica gel could be adjusted by altering the structures of the dyes, and the RH sensing property of the final hybrid materials could be further regulated. R2-3/SG hybrid fabricated by R2 with large steric isooctyl groups possessed indiscernible RH sensing properties, while the R1-3/SG without hydrogen bond interactions between dyes and substrate was more susceptible to water vapor. The surface properties and specific surface area of the substrate were critical for RH sensing. RH sensing properties were not presented for the substrates without hydroxyl groups or low specific surface area such as PET or PP fibers. Moreover, we have prepared a kind of C1 loaded paper strips, which exhibited potentially ability in anticounterfeiting application.
研究领域:
材料科学
·
化学
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DOI
高影响因子
ELECTROCHIMICA ACTA
·
2019
·
IF 5.383
Zhe Li,Qi Kang,Lu Chen,Bin Zhang,Guizheng Zou,Dazhong Shen
The poor aqueous stability of perovskite nanocrystals (NCs) limits their electrochemical applications. Herein, we reported a waterproof and conductive silica gel shell encapsulating CsPbBr 3 NCs, enhancing its aqueous stability and radiative-charge-transfer efficiency. Upon introducing small volume of CsBr aqueous solution in hexane containing tetramethoxysilane (TMOS) and Cs 4 PbBr 6 NCs, the conversion reaction of Cs 4 PbBr 6 → CsPbBr 3 +3CsBr was triggered to form Cs 4 PbBr 6 @CsPbBr 3 @silica gel (CsBr) hybrid. The silica gel shell can block the contact between CsPbBr 3 NCs and bulk aqueous phase. The CsBr enclosed in the silica gel can reduce the conversion rate and increase dramatically the electrical conductivity of the silica gel. The electrochemiluminescence (ECL) of CsPbBr 3 NCs in aqueous phase was enhanced greatly. The strong ECL of CsPbBr 3 NCs in the hybrid was still observed after stored in CsBr solution for 30 day. The as-obtained perovskite hybrid displays improved electrochemical charge-injecting performance and radiative-charge-transfer in ECL. Annihilation ECL demonstrates that all the electrons injected onto the perovskite hybrid can recombine with the holes injected onto it for light-emitting. Both annihilation and co-reactant ECL, as well as photoluminescence reveal that encapsulating CsPbBr 3 NCs into a conductive and waterproof silica gel shell is favorable to enhance aqueous performance of perovskite NCs with negligible effects on their excited states. The ECL of the core-shell perovskite hybrid was applied to detect dopamine in the concentration range of 0.01–10 μM, with the limit of detection of 3 nM.
研究领域:
材料科学
·
电化学
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产品关联
DOI
高影响因子
CHEMICAL ENGINEERING SCIENCE
·
2019
·
IF 3.372
Chuan Wang,Qingqing Yang,Jieyu Wang,Jun Zhao,Xiaoyue Wan,Zhen Guo,Yanhui Yang
In recent years, machine learning (ML) has been extensively attempted on all sections in development of functional materials such as material discovery, determination of experimental factors for the discovered materials, and tuning experimental factors to produce the selected materials. Design of experiment (DoE) and response surface methodology (RSM) are efficient strategies to screen experimental factors and study the correlation between material property and experimental factors. Usually, second order quadratic model is applied to construct the response surface. ML-based models, such as Gaussian process and neural networks, have also be implemented into the RSM. In this work, a ML model based on support vector machine (SVM) was built to analyze the high-throughput experimental data from DoE. Silica xerogel was chosen as a model material, the goal was to control the diversity of the silanol groups on the surfaces of silica. Silica samples were prepared following the central composite design (CCD) in a segmented continuous flow reactor. Sodium silicate and CO 2 were used as the raw materials. Both quadratic model and SVM model were studied on the analysis of experimental data. SVM model showed better performance in fitting and predicting, which was attributed to the advantage of handling complex nonlinear correlations. Based on the response surface generated by the SVM model, correlations between experimental factors and diversity of silanol groups were identified. With the guidance of the SVM model, two samples with desired silica surface properties were prepared and attempted as supporting material s for heterogeneous catalysis. The impact of surface silanol groups on the catalytic performance was discussed.
研究领域:
材料科学
·
化学工程
·
催化科学
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DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2019
·
IF 8.355
Shaojuan Zeng,Junli Wang,Pengfei Li,Haifeng Dong,Hui Wang,Xiaochun Zhang,Xiangping Zhang
The emerging of ionic liquids (ILs) provides a promising way to efficiently separate ammonia (NH 3 ) and simultaneously recover NH 3 due to their negligible volatility, good affinity with NH 3 and designable structures. However, the relatively high viscosities of ILs and the limited gas-liquid interface severely affect gas diffusion in ILs, which hinders their practical use in industries. In this work, in order to overcome the mass-transfer limitations of ILs in gas separation, three metal ILs (MILs), [Bmim] 2 [CuCl 4 ], [Bmim] 2 [NiCl 4 ] and [Bmim] 2 [Co(NCS) 4 ], with good affinity toward NH 3 were incorporated into porous silica gels with large surface area and abundant hydroxyl groups, by an impregnation-vaporization method to form novel MIL@silica gel composites for rapid, efficient and reversible adsorption of NH 3 . The FT-IR and BET results indicated that the prepared adsorbents with different loadings of MILs are mesoporous composites. The [Bmim] 2 [Co(NCS) 4 ]@silica gel composites not only show much higher NH 3 capacity and NH 3 selectivity than pristine silica gel and faster adsorption rate than the corresponding pure MILs, but also exhibit excellent reversibility. The highest capacity of NH 3 adsorption up to 99.808 mg NH 3 ·(g adsorbent) −1 in 15 min was obtained when the loading of [Bmim] 2 [Co(NCS) 4 ] in the MIL@silica gel composite was 48.89 wt%, which could be attributed to the synergistic interaction of the complexation and hydrogen bonding between cobalt coordinated anion and NH 3 as well as mesoporous structures. Moreover, the NH 3 absorbed by the [Bmim] 2 [Co(SCN) 4 ]@silica gel can be completely released in 15 min, and no obvious losses in NH 3 capacity were detected during five adsorption and regeneration cycles, indicating great potentials as adsorbents for NH 3 separation applications.
研究领域:
化学工程
·
材料科学
✓ 已验证
DOI
高影响因子
POLYMER DEGRADATION AND STABILITY
·
2025
·
IF 7.4
Dazhi Su,Zhiqian Liu,Hengxin Zhong,Ju Tang,Fuping Zeng
Packaging insulation is a key factor restricting the reliability of power electronic devices under high power density and extreme conditions. In this study, hexagonal boron nitride (h-BN) was used as a filler to prepare silicone gel based composite insulators via physical modification. The effect of BN doping on insulation performance and its mechanism were explored, combining microstructural analysis and molecular dynamics simulations. The results indicate that the doping of BN enhances the crosslinking density of the material and results in a more compact material structure, thereby improving the breakdown voltage of the composite material. However, the insulation defects introduced by filler agglomeration cause the breakdown voltage to decrease at high doping ratios. The breakdown voltage is highest when the BN content is 2 %, with more pronounced improvement under 100 V/ns. Charge migration at the interface between the matrix and filler dominates the changes in dielectric properties, leading to a significant increase in interfacial polarization in the low-frequency region and conductive polarization in the high-frequency region. Both the real and imaginary parts of the relative permittivity increase with the addition of BN. Based on the key performance indicators of various engineering projects, when the BN doping concentration is 2 %, the breakdown voltage under high voltage rise rate (d u /d t ) can be improved by 39.99 % while achieving a synergistic improvement in insulation performance, thermal stability, and thermal conductivity. This approach holds promise for widespread application in the packaging of next-generation wide-bandgap power devices.
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产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2020
·
IF 10.652
Zeyou Meng,Yuheng Liu,Xiao Li,Zichuan Ma
Volatile methylsiloxanes (VOSiC) are impurities present in trace amounts in biogas produced by the anaerobic digestion of organic wastes in landfill and sewage plants. Efficient removal of these impurities is required due to the restrictions posed by them on the application of biogas as an alternative energy resource. In this study, methyl-functionalised silica gels (MFS) have been prepared via a hydrolysis and condensation approach using double precursor (TEOS and MTS) in methanol–water medium for achieving effective removal of a model VOSiC - hexamethyldisiloxane (L2). The developed gels have been characterized by N 2 -BET, FTIR, SEM-EDS and XRD. The results reveal that the as-synthesized MFS materials have well-developed micropore structure and superhydrophobicity. Among the developed materials, MFS2 sample obtained with a MTS/TEOS ratio of 1/1 ( v/v ) exhibits the highest specific surface area (1261.3 m 2 g −1 ), micropore volume (0.52 cm 3 g −1 ) and total pore volume (1.03 cm 3 g −1 ), along with superior water contact angle (123.5°). The non-crystalline nature and sponge-like structure of MFS are confirmed by XRD and SEM analyses. The adsorptive performance of MFS materials for L2 siloxane is measured to be 14.9–18.3 times higher than that of the unmodified silica in terms of the breakthrough adsorption capacity ( Q B ). Also, the adsorption capacities of MFS materials are noted to be linearly related to the specific surface area and micropore volume, along with positively affected by the total pore volume and water contact angle. From a series of the experimental results of adsorption of L2 by MFS2, an empirical equation is developed for reflecting the correlation of the breakthrough time and inlet concentration. Use of lower temperature is concluded to result in better overall siloxane adsorption levels. The Q B reaches an optimal value of 346.3 mg L2 g −1 at 0 °C using 83.82 mg L −1 of L2 with N 2 as the carrier gas. The developed MFS adsorbent can be readily regenerated for reuse by heating at 80 °C, and an insignificant fluctuation in the dynamic adsorption behavior is observed even after consecutive 5 adsorption/desorption cycles.
研究领域:
环境科学
·
化学工程
·
材料科学
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）