SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Zhongming Zhang,Enfang Gou,Zhiying Zhao,Rui Wu,Rui Fang,Weipeng Guo,Jie Yao
Organophilic pervaporation (PV) mixed matrix membranes (MMMs) have enormous potential for organic wastewater treatment due to their environmental friendliness and high efficiency. However, developing a high-flux PV membrane remains challenging. In this work, the nanocage-like hollow ZIF-71(h) (HZIF-71(h)) polyhedral nanocrystals were synthesized by heteroepitaxial growth of a ZIF-71(h) shell and successive excavation of a ZIF-67 core. The resultant HZIF-71(h) nanocrystals were blended with poly (ether block amide) (PEBA) matrix to fabricate MMMs for phenol/water separation. Results from several characterization techniques confirmed the successful preparation and formation mechanism of HZIF-71(h). Further, a series of experiments were conducted using the composite membranes to explore the impact of filler type, filler loading, operating temperature, and feed concentration on the separation performance. The incorporation of ZIFs facilitated phenol permeation while limited water transport, thereby resulting in increased separation factor. Notably, the HZIF-71(h)/PEBA-21 MMM exhibits a higher phenol flux in comparison to ZIF-71/PEBA-21 and ZIF-67/PEBA-21 MMMs, indicating the importance of the low-resistance hollow structure. The HZIF-71(h)/PEBA-21 MMM exhibits outstanding pervaporation performance with a separation factor of 15.86 and a phenol flux of 17.32 g·m −2 ·h −1 , respectively, displaying an improvement of 41.2 % and 6.4 % compared to the PEBA/PVDF membrane. Furthermore, this composite membrane demonstrated outstanding durability during continuous testing for 84 h, implying a promising potential for phenol separation.
研究领域:
材料科学
·
环境工程
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2020
·
IF 10.652
Kezhu Xu,Jin Wu,Qunling Fang,Linfeng Bai,Jinyu Duan,Jiaxing Li,Huajian Xu,Ailing Hui,Lingyun Hao,Shouhu Xuan
The organic pollutants and heavy metal ions are critical harmful substances in waste water because they destroy the ecological systems and lead diseases to animals and human beings. Unfortunately, the simultaneously remove of them in one system is still a challenge due to their different treating mechanism. Herein, a novel magnetic h-Fe 3 O 4 @Au/Polydopamine (Au/PDA) hybrid hollow nanosphere which can both absorb the potentially toxic U(VI) ions and catalyze the reduction of the 4-nitrophenol is reported. By using a simple in situ redox-oxidizing polymerization method, the h-Fe 3 O 4 hollow nanosphere is well encapsulated by the Au/PDA hybrid shell to form the dual-functional magnetic hollow nanocomposites. Owing to the hollow interior, uniform and functional PDA coating, and high active Au nanocrystals, the final h-Fe 3 O 4 @Au/PDA hollow nanosphere possesses high potential in nanocatalysis, heavy metal ions adsorption, and drug delivery. Because of the PDA protection, the h-Fe 3 O 4 @Au/PDA nanosphere can even keep 90% activity after 7 cycling catalytic reactions on reduction of 4-nitrophenol. Similarly, the h-Fe 3 O 4 @Au/PDA exhibits a good adsorption effect for U(VI) in nuclear waste and its adsorption capability reaches to 82.9 mg·g −1 by 6 successive adsorption–desorption experiments. Due to the facile magnetic separation, the h-Fe 3 O 4 @Au/PDA nanosphere can be easily collected by applying an external magnetic field. In summary, such a multifunctional recyclable h-Fe 3 O 4 @Au/PDA nanosphere with green and facile synthesis, easy manipulation, efficient adsorption performance and good catalytic activity possesses broad application potential in treatment of coexisting toxic water pollution.
研究领域:
环境科学
·
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
CEMENT & CONCRETE COMPOSITES
·
2024
·
IF 10.8
Guangpeng He,Deyu Kong,Xiaoguang Chen,Shujing Fan,Tao Meng,Jiabin Li
In this paper, low-cost dihydrate gypsum (CaSO 4 ⋅2H 2 O) was used as calcium source together with sodium metasilicate solution to prepare calcium silicate hydrate (C-S-H) gels through a mechanochemical activation strategy by using planetary and vibrational ball-milling. The influences of the prepared C-S-H gels on hydrating and hardening properties of super-retarded cement-based materials with sucrose were investigated. The results showed that CaSO 4 ⋅2H 2 O reacted with sodium metasilicate solution under mechanochemical effect during both planetary and vibrational ball-milling, although CaSO 4 ⋅2H 2 O was just slightly dissolved in water. It was also interestingly found that the C-S-H gels can continuously form while resting for a certain time after ball-milling. Under the mechanochemical activation, the prepared C-S-H gels had complete characteristic diffusion peaks and were composed of layered, flocculent and fibrous structures. While incorporating the prepared C-S-H gels into the super-retarded cement paste with sucrose, the cement hydration was greatly accelerated and the compressive strength of the hardened cement-based materials was also effectively improved at early age as expected. Through X-ray diffraction (XRD) analysis, it was found that C-S-H gels can effectively promote the growth of CH crystals along the (001) and (101) crystal planes. The scanning electron microscopy (SEM) results supported that the C-S-H gels inhibited the refinement of ettringite (AFt) crystals in super-retarded HCP with sucrose, which was more obvious at 28 d.
研究领域:
建筑材料学
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无机材料科学
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土木工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CATALYSIS
·
2012
·
IF 6.002
Xiang Li,Yi Shi,Zhoujun Wang,Yahong Zhang,Yi Tang
In this paper, uniform H-β nanozeolite microsphere (β-ZMS) prepared by polymerization-induced colloid aggregation, combined with an immobilized lipase B from Candida antarctica (commercially available Novozym® 435), is applied as a racemization catalyst to the one-pot dynamic kinetic resolution (DKR) of aromatic sec -alcohols. The DKRs of various aromatic sec- alcohols can be carried out with high selectivity and conversion under optimum conditions. Importantly, it is found that, compared to commercial zeolites β (C-β), β-ZMSs display high selectivity for small sec- alcohol molecules because their shorter microporous channels reduce the diffusion time of substrate/product in the three-dimensional framework, and thereby decrease the possibility of secondary reactions. However, the β-ZMSs show a high racemization rate in the DKR of large sec- alcohol molecules, such as racemic 1-(1-naphthyl)-ethanol, thanks to their abundant accessible active sites. This observation will not only benefit the performance of acidic zeolite catalysts in one-pot DKR systems but also provide a new perspective on the application of nanozeolites in catalysis.
研究领域:
催化化学
·
生物化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
·
2024
·
IF 11.2
Haizhen Liu,Liwen Lu,Hui Luo,Jiayi Deng,Guangxu Li,Hua Ning,Yi Fan,Cunke Huang,Zhiqiang Lan,Wenzheng Zhou,Jin Guo,Xinhua Wang
The Li-Mg-B-H composite (2LiBH 4 + MgH 2 ) is acknowledged as a promising material for hydrogen storage due to its large hydrogen capacity (11.4 wt.%). However, the sluggish kinetics and poor reversibility make it difficult to be practically used. In this work, the hydrogen storage performances of 2LiBH 4 + MgH 2 have been significantly improved by a hybrid of bulk NbC and layered Nb 4 C 3 MXene (denoted as “Nb-C”). The 2LiBH 4 + MgH 2 + 6 wt.% Nb-C can release 8.5 wt.% H 2 within 30 min at 400°C and the dehydrogenated composite can absorb 9.3 wt.% H 2 within 30 min at 350°C and 7.5 MPa H 2 . The reversible dehydrogenation capacity maintains at 8.4 wt.% after 24 cycles, with a capacity retention ratio of 95.4%. By contrast, the undoped 2LiBH 4 + MgH 2 suffers from serious capacity degradation, with the capacity decreased dramatically to 3.5 wt.% after 3 cycles. Microstructural studies revealed that the doped composite has uniform particle and elemental distributions and possesses various multiphase interfaces of LiH/MgB 2 /NbC/Nb 4 C 3 , which is beneficial to hydrogen diffusion during the hydrogen uptake and release process. Theoretical studies by first principle calculation presented an extended bond length of the Mg-H and B-H bonds in the 2LiBH 4 + MgH 2 + NbC system, which may also explain the improved hydrogen storage properties of 2LiBH 4 + MgH 2 by addition of Nb-C. This work provides new insights into the role of transition metal carbides in regulating the Li-Mg-B-H hydrogen storage materials both experimentally and theoretically.
研究领域:
材料科学
·
理论计算
✓ 已验证
产品关联
DOI
高影响因子
Chemical Engineering Journal Advances
·
2020
·
IF 0
Jiuhu Zhao,Zhengzhong Wen,Rongshu Zhu,Zhi Li,Ran Ding,Yongji Zhu,Tingkun Gu,Rong Yang,Zhenye Zhu
In this paper, In-metal oxide/H-Beta catalysts were synthesized by ion exchange method and In-Co 3 O 4 /H-Beta exhibited the highest catalytic activity for the selective catalytic reduction of NO x with CH 4 in presence of H 2 O and SO 2 . Thus, the synthesis conditions of In-Co 3 O 4 /H-Beta were optimized. The results showed that In-Co 3 O 4 /H-Beta exhibited excellent catalytic performance and high CH 4 selectively when the synthesis was carried out by ion exchange method, the ratio of Si and Al in H-Beta was 25, the ratio of Co 3 O 4 and H-Beta was 5:40, the concentration of ion exchange liquid was 0.033 M and calcination temperature was 500 °C. The NO x removal efficiency was about 87.6 % and N 2 selectivity could reach 96.3% in the presence of H 2 O and SO 2 . Through a series of characterizations, it was concluded that In-Co 3 O 4 /H-Beta owned stable catalyst structure, abundant Brønsted acid sites and the highest ratio of InO + /In 2 O 3 under the optimal synthesis conditions. In addition, the doped of Co 3 O 4 could inhibit the adsorption of sulfate species on the surface of In/H-Beta catalyst, leading to the excellent H 2 O and SO 2 resistance property.
研究领域:
环境科学
·
催化化学
✓ 已验证
DOI
Frontiers of Chemical Science and Engineering
·
2017
·Vol. 11
·期 4
·564-574
·
IF 1.712
Song Baodong,Li Yongqiang,Cao Gang,Sun Zhenhai,Han Xu
In the transformation of methanol to gasoline (MTG), the selectivity to gasoline and the aromatic content in the produced gasoline are important factors. The catalytic activities of steam-treated and non-steam-treated nano-scale H-ZSM-5 (NHZ5) catalysts impregnated with Ag(I), Zn(II) or P(V) have been investigated in a continuous flow fixed bed reactor. The NH 3 -TPD results showed that after impregnation, the Ag/NHZ5, Zn/NHZ5 and P/NHZ5 catalysts contained comparatively more strong, medium-strong and weak acid sites, respectively. Treatment with steam decreased the number of acid sites in all the catalysts, but the pore volumes in the catalysts were larger which improved carbon deposition resistance resulting in prolonged lifetimes. After 6 h of MTG reaction, the selectivity to gasoline for the steam-treated catalysts,
\(Ag_{H_2 O} /NHZ5\) , \(Zn_{H_2 O} /NHZ5\) and \(P_{H_2 O} /NHZ5\) were 70.5, 68.4 and 68.7 wt-%, respectively, whereas their respective aromatic contents in the produced gasoline were 61.9, 55.4 and 39.0 wt-%. Thus \(P_{H_2 O} /NHZ5\) is the most promising catalyst for MTG applications which can meet the China IV gasoline standard that the amount of aromatics in gasoline should be less than 48 wt-%.
研究领域:
催化化学
·
能源化工
·
材料科学
·
表面科学
·
石油炼制
✓ 已验证
DOI
高影响因子
JOURNAL OF ORGANIC CHEMISTRY
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2024
·
IF 3.3
Jun-Feng Yang,Yun-Fei Liu,Lin-Lin Wei,Kai-Kai Qiao,Yan-Qiu Zhao,Lei Shi
The Minisci-type dehydrogenative coupling of N-heteroaromatic rings with inert C–H or Si–H partners via visible-light-catalyzed hydrogen atom transfer has been reported. This methodology allows the coupling reactions to be carried out in water as a solvent under air atmospheric conditions with visible-light illumination. A wide range of inert C–H and Si–H partners could be directly coupled with various N-aromatic heterocycles to deliver products in good to excellent yields.
研究领域:
有机化学
·
光化学
✓ 已验证
DOI
PubMed
高影响因子
Journal of Building Engineering
·
2025
·
IF 7.4
Juanhong Liu,Yayun Xi,Fanghui Han,Lingzhi Guo,Jinmei Hu
This study investigates the influence of aluminum incorporation on the chemical composition, morphology, silicate chain structure, and functional groups of C(-A)-S-H gel through micro- and nanoscale characterization. Based on experimental data, an atomic-scale structural model was constructed to closely reflect realistic Ca/Si and Al/Si ratios as well as Q n distributions, and to explore the effects of aluminum content on the mechanical properties and failure mechanisms of C-A-S-H at the atomic level. Results show that at low Al/Si ratios, Al can be effectively incorporated into the C-S-H gel; however, when Al/Si exceeds 0.10, Al-containing secondary phases start to precipitate. Al atoms bridge defects in silicate chains, extend the length of aluminosilicate chains, and form crosslinking structures along the z direction, with the degree of crosslinking increasing with Al content. Simulation results further indicate that Al incorporation restricts the diffusion pathways of interlayer water molecules, thereby enhancing gel structural integrity. Meanwhile, the formation of a three-dimensional crosslinking network substantially improves mechanical performance, significantly increasing Young's modulus and tensile strength in the y and z directions—especially enhancing interlayer cohesion and ductility along the z direction . Under tensile loading, stress-induced hydrolysis and bond depolymerization accelerate bond cleavage and hydroxyl formation within the C-A-S-H.
✓ 已验证
产品关联
DOI
高影响因子
RARE METALS
·
2023
·Vol. 43
·期 3
·1153-1166
·
IF 8.8
Lu Li-Wen,Luo Hui,Li Guang-Xu,Li Yun,Wang Xin-Hua,Huang Cun-Ke,Lan Zhi-Qiang,Zhou Wen-Zheng,Guo Jin,Ismail Mohammad,Liu Hai-Zhen
The Li-Mg-B-H composite (2LiBH 4 + MgH 2 ) has a high capacity of 11.4 wt% as a hydrogen storage material. However, the slow kinetics and poor cycling stability severely restrict its practical applications. In this work, a layered Nb 2 C MXene was first synthesized and then introduced to tailor the kinetics and cycling stability of the Li-Mg-B-H composite. The milled 2LiH + MgB 2 composites were initially hydrogenated to obtain the 2LiBH 4 + MgH 2 composites. The 2LiBH 4 + MgH 2 + 5 wt% Nb 2 C can release 9.0 wt% H 2 in 30 min at 400 °C, while it is only 2.7 wt% for the undoped 2LiBH 4 + MgH 2 . The dehydrogenation activation energies of MgH 2 and LiBH 4 are 123 and 154 kJ·mol −1 respectively for the 5 wt% Nb 2 C-doped composite, lower than the undoped composite (164 and 165 kJ·mol −1 ). The 2LiBH 4 + MgH 2 + 5 wt% Nb 2 C possesses excellent cycling stability, with the reversible capacity only slightly reduced from 9.4 wt% for the 1st cycle to 9.3 wt% for the 20th cycle. Nb 2 C keeps stable in the composite and acts as an efficient catalyst for the Li-Mg-B-H composite. It is believed that both the layered structure and the active Nb element contribute to the enhanced hydrogen storage performances of the Li-Mg-B-H composite. This work confirms that the Nb 2 C MXene with layered structure has a significant enhancing impact on the Li-Mg-B-H hydrogen storage materials, which is different from the bulk NbC. Graphical abstract
研究领域:
材料科学
·
能源化学
·
纳米催化
·
储氢技术
·
固体化学
✓ 已验证
DOI
高影响因子
CHEMISTRY-A EUROPEAN JOURNAL
·
2017
·Vol. 23
·期 41
·9831-9837
·
IF 5.317
Qiang Cao,Qing Yin,Qi Chen,Zhi-Bing Dong,Bao-Hang Han
Graphical Removed from the mix : The synthesis of fluorinated iron–porphyrin conjugated porous polymers through direct C−H arylation polymerization is described (see scheme). The application of these polymers as heterogeneous catalysts for Baeyer–Villiger oxidation is also discussed. By considering the high reactivity of fluorinated iron–porphyrin and good stability of porphyrin-based porous polymers, fluorinated iron–porphyrin conjugated porous polymers ( FPOP-3 – 6 ) were synthesized through direct C−H arylation polymerization. The obtained materials are chemically and thermally stable, of which FPOP-3 exhibits the highest Brunauer–Emmett–Teller specific surface area (about 840 m 2 g −1 ). For functional studies of the obtained polymers as heterogeneous catalysts, catalytic transformation of cycloketones into lactones by oxygen through Baeyer–Villiger oxidation was used as a model reaction. Fluorinated phenyl substituents of the iron–porphyrin not only are beneficial to the conversion, but also can stabilize the porphyrin to resist catalyst breakdown. The polymer FPOP-3 , with high porosity, exhibits the best catalytic efficiency and recycling effect. The recovered catalyst also shows good catalytic activities after recycling three times with a small loss in yield.
研究领域:
材料化学
·
催化化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY
·
2012
·Vol. 51
·期 6
·1405-1416
·
IF 3.919
Cheng-Guang Mu,Xiao-Dong Fan,Wei Tian,Yang Bai,Zhen Yang,Hao Yao,Heng Chen
We report on the synthesis of an H-shaped polymer bonding β-cyclodextrin (β-CD) at branch points and influences of attached β-CD on physical properties. First, a poly(ethylene glycol)(PEG)-based functional macroinitiator bearing two azidos and four chlorines at chain-ends (PEG-2N 3 (-4Cl)) was prepared via terminal modification reactions. Then, PEG-2N 3 (-4Cl) was applied to initiate the atom transfer radical polymerization of N-isopropylacrylamide, leading to the synthesis of an H-shaped block polymer with PEG as the central chain and poly( N -isopropylacrylamide) (PNIPAM) as side-arms (PEG-2N 3 (-4PNIPAM)). Azido groups were at the branch points of the polymer. Finally, the click reaction between PEG-2N 3 (-4PNIPAM) and alkynyl monosubstituted β-cyclodextrin (β-CD) afforded another H-shaped polymer with two β-CDs bonding at the polymer branch points (PEG-2CD(-4PNIPAM)). The glass transition temperature ( T g ) and lower critical solution temperature (LCST) of the H-shaped polymer increased after the attachment of β-CD. The self-assembly and thermal responsive behaviors, as well as the encapsulation behaviors of PEG-2CD(-4PNIPAM) were also altered. When temperature was below the LCSTs, PEG-2N 3 (-2PNIPAM) dissolved in water molecularly, whereas PEG-2CD(-4PNIPAM) could self-assemble into nano-sized micelles. After the LCST transitions, PEG-2N 3 (-4PNIPAM) aggregated into micron-sized unstable particles, whereas PEG-2CD(-4PNIPAM) transformed into PNIPAM-cored nanomicelles. Besides, PEG-2CD(-4PNIPAM) can encapsulate doxorubicin below its LCST due to the formation of micelles. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013
研究领域:
高分子化学
·
材料科学
✓ 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）