APPLIED SURFACE SCIENCE
·
2017
·
IF 3.387
Xueliang Cui,Yunfeng Zheng,Meng Tian,Zhengping Dong
A novel yolk–shell-structured material (Fe 3 O 4 @γ-AlOOH-YSMs) with hierarchical γ-AlOOH flakes as the mesoporous shell and Fe 3 O 4 nanoparticles (NPs) in the hollow core was prepared by using Fe 3 O 4 @SiO 2 NPs as the seeds as well as NaAlO 2 and urea as the precursor. The prepared Fe 3 O 4 @γ-AlOOH-YSMs were used as a catalyst support for fabricating a Pd/Fe 3 O 4 @γ-AlOOH-YSMs nanocatalyst with no obvious aggregation of the Pd NPs. The Pd/Fe 3 O 4 @γ-AlOOH-YSMs nanocatalyst was utilized for the catalytic reduction of the widely used and highly toxic 4-nitrophenol, rhodamine B, methylene blue, and methyl orange; and showed excellent catalytic activity as compared with other noble-metal-based catalysts. Furthermore, the Pd/Fe 3 O 4 @γ-AlOOH-YSMs nanocatalyst also can be easily separated from the reaction mixture and reused for at least ten times without any obvious decrease in the catalytic activity, indicating its reusability and stability.
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SEPARATION AND PURIFICATION TECHNOLOGY
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2016
·
IF 3.299
Xiaohui Wu,Mingjie Huang,Tao Zhou,Juan Mao
A novel magnetic molecular imprinting composites (MICs) were successfully synthesized through cross-linked chitosan and γ-Fe 2 O 3 particles, and the selective removal of aqueous NOR was demonstrated. The γ-Fe 2 O 3 particles embedded in MICs were still of intrinsic crystal and complexed with both amino and hydroxyl groups of chitosan. Adsorption behavior of NOR onto MICs could be described by the pseudo-second-order kinetic and the Langmuir isotherm model. Excellent selective NOR adsorption was identified with competition of sulfadiazine (SD), ofloxacin (OFL) and phenol, respectively. It could be ascribed to the memory cavities for NOR molecules, as well as the formation of triple intermolecular hydrogen bonds with suitable angle and length. Furthermore, application feasibility of MICs in NOR-spiked municipal wastewater treatment plant (WWTP) effluent was investigated. Competing with the effluent organic matters (EfOM), effective adsorption performance of NOR could be still obtained. Effect of humic and fulvic acid-like organics could be effectively reduced, while adsorption of tryptophan-like substances was slightly enhanced. In addition, it was found that Fenton-like oxidation instead of NaOH washing would be more appropriate for the multiple regenerations of MICs. The former would reserve more memory cavities and lead to oxidative decomposition of the desorbed NOR into micromolecular organics of low environmental impacts.
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RSC Advances
·
2016
·Vol. 6
·期 61
·55878-55883
·
IF 3.289
Jinxing Chen,Feng Chen,Yiyao Wang,Mozhen Wang,Qichao Wu,Xiao Zhou,Xuewu Ge
A sub-micron sized highly-crosslinked poly(ethyleneglycol dimethacrylate) (PEGDMA) microsphere supported nano-Au catalyst (PEGDMA@AuNP) was successfully prepared through a one-step synthesis method at room temperature and ambient pressure, taking advantage of the γ-ray radiation effect on a simple one-pot system, i.e. a methanol–water solution containing EGDMA, 4-VP, and HAuCl4. Electron microscopy, XPS, and XRD analyses proved that AuNPs of several nanometers had been synthesized and loaded simultaneously with the formation of crosslinked PEGDMA microspheres when the adsorbed dose rate and the initial concentration of HAuCl4 were controlled within a narrow range, i.e. 35–80 Gy min−1 and below 1 mmol L−1 of [HAuCl4]. The size of the prepared PEGDMA@AuNP microspheres changed little with the dose rate, but decreased with the initial [HAuCl4], from 900 nm at 0.1 mmol L−1 to 680 nm at 1 mmol L−1. At the same time, the size of AuNPs increases with the initial [HAuCl4], from 8 nm at 0.1 mmol L−1 to 35 nm at 1 mmol L−1. The prepared PEGDMA@AuNP microspheres can be dispersed stably in both water and organic solvent, CH3CN. They exhibit excellent catalytic efficiency not only on the reduction of Fe(CN)63− by NaBH4 in aqueous solution, but also on the cis–trans isomerization of azobenzenes in CH3CN at room temperature. A satisfactory repeatability of the catalytic performance of the prepared PEGDMA@AuNP microspheres was achieved in organic solvents. This work opens a new green simple and economic way to the synthesis of efficient and chemically-stable polymer-supported nano-metal catalysts.
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Catalysis Science & Technology
·
2016
·Vol. 6
·期 16
·6305-6310
·
IF 5.287
Jin-Gang Yin,Yi Gong,Xiao-Yan Zhang,Gao-Wei Zheng,Jian-He Xu
A novel non-heme chloroperoxidase (SvGL) with promiscuous (−)-γ-lactamase activity towards Vince lactam was identified from Streptomyces viridochromogenes by genome data-mining. SvGL possesses high activity and excellent thermal stability and enantioselectivity. Furthermore, it is able to tolerate extremely high substrate concentrations (4.0 M, 436.5 g L−1). Using the newly discovered (−)-γ-lactamase as a biocatalyst, an efficient and environmentally benign process for the production of (+)-γ-lactam was developed. The process allowed an enantioselective resolution of 436.5 g L−1 racemic γ-lactam with only 0.2 g L−1 lyophilized cell-free extract, affording an extremely high substrate/catalyst ratio of 2183 (g g−1), a space-time yield of 458 g L−1 d−1, and a very low E factor (environmental factor) of 5.7 (kg waste per kg product) even when the process water is included.
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JOURNAL OF CATALYSIS
·
2016
·
IF 7.354
Ruifang Nie,Rui Sang,Xiaojun Ma,Yang Zheng,Xu Cheng,Weijian Li,Li Guo,Hui Jin,Yong Wu
A copper-γ-cyclodextrin complex immobilized on hexagonal boron nitride ( h -BN@γ-CD@Cu(OAc) 2 ) has been prepared for the first time. This recoverable and reusable heterogeneous catalyst can be used in the click synthesis of 1,2,3-triazoles via a one-pot three-component reaction of boracic acid, terminal alkynes, and sodium azide at room temperature in water. FT-IR, XRD, SEM, XPS, TG, and ICP-AES techniques were used to characterize the catalyst. In general, this reaction, with the aid of this new catalyst, afforded the corresponding products with good yields and excellent tolerance of the functional groups.
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ENVIRONMENTAL POLLUTION
·
2024
·
IF 7.6
Qian Xu,Qian Xue,Shengmei Tan,Zhiliang Cheng,Xueqiang Qi,Chaoqun Yan
A low band gap and visible light-responsive heterogeneous Photo-Fenton catalyst of γ-Fe 2 O 3 /CQDs micron composite was prepared under the one-pot hydrothermal method. The Photo-Fenton degradation of γ-Fe 2 O 3 /CQDs towards dye solution of rhodamine B(RhB), methyl blue (MB), and methyl orange (MO) was studied comparatively with α-Fe 2 O 3 . The γ-Fe 2 O 3 /CQDs exhibited remarkable catalytic performance for various dyes and with a first-order rate ( k ) of 14 times higher than that of initial α-Fe 2 O 3 with a low concentration of H 2 O 2 of 0.049 mmol . L −1 and a wider pH range of 3.1–7.1. The microstructure of the compounds was observed by XRD, SEM, TEM, FT-IR, and XPS characterization results suggested that the γ-Fe 2 O 3 /CQDs nanocomposite was formed through the stable Fe–O–C bonds, thus, the band gap decreased, and it is more favorable for the distance of holes and electrons. The free radical trapping experiment and EPR analysis indicated that •OH and 1 O 2 were the major active species during the typical photo-Fenton reaction. What's more, the γ-Fe 2 O 3 /CQDs also exhibited good stability and magnetic properties. DFT conclusion shows that the mechanism of the potential determination step (PDS) on α-Fe 2 O 3 (220) is the cleavage of H 2 O 2 with an energy barrier of only 0.08 eV, which is 0.54 eV lower than that of OH* on γ-Fe 2 O 3 (220). Thus it can be deemed that γ-Fe 2 O 3 /CQDs perform much higher catalytic activity for the dissociation of H 2 O 2 than α-Fe 2 O 3 . This work gives a feasible and economical countermeasure of visible light Photo-Fenton dispose of dye wastewater with a recyclable magnetic γ-Fe 2 O 3 /CQDs micron catalyst.
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Journal of Materials Chemistry A
·
2017
·Vol. 5
·期 14
·6664-6676
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IF 8.867
Zepei Bao,Lin Ye,Beibei Fang,Lijun Zhao
Herein, Fe0.32Co0.68 binary metal nanoparticles synthesized at room-temperature were loaded onto a novel hierarchical flower-like γ-Al2O3@C composite, which improved the stability and dispersity of the Fe0.32Co0.68 nanoparticles. The freshly prepared Fe0.32Co0.68/γ-Al2O3@C displayed good adsorption of Orange II (100 mg L−1, 973.55 mg g−1). Subsequently, the used Fe0.32Co0.68/γ-Al2O3@C adsorbent (Fe–Co oxide/γ-Al2O3@C) was reused as a peroxymonosulfate (PMS) catalyst. Amazing results were obtained, which demonstrated that Fe–Co oxide/γ-Al2O3@C can highly efficiently decompose Orange II (60 mg L−1, 1 min; 90 mg L−1, 2 min, 120 mg L−1, 7 min and 150 mg L−1, 10 min) as a PMS catalyst. It also exhibited good general degradation of different organic pollutants and excellent reusability (98%, tenth cycle) due to the structural stabilities of γ-Al2O3@C. Further, an experiment was carried out to treat high concentrations of Orange II (200 mg L−1) with the Fe0.32Co0.68/γ-Al2O3@C nanocomposite. After adsorption, PMS was added, and 98% degradation occurred within 5 minutes. The combination of adsorption and PMS advanced oxidation techniques may be one of the effective ways to deal with high-concentration dye wastewater.
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Advanced Optical Materials
·
2024
·Vol. 12
·期 22
·2400722
·
IF 8
Zhen-Yu Ma,Bai-Sheng Zhu,Xue-Chen Ru,Yi-Chen Yin,Li-Zhe Feng,Guan-Jie Ding,Mei-Yu Zhou,Yong-Hui Song,Hong-Min Zhou,Cheng-Ming Wang,Jing-Ming Hao,Hong-Bin Yao
Inorganic CsPbI 3 perovskite has great potential to fabricate deep-red light-emitting diodes (LEDs) owing to excellent color purity, thermal stability, and carrier mobility. However, fabricating high-quality CsPbI 3 thin films for high-performance LEDs remains challenging. While it is demonstrated that hydrogen bonds between organic ammonium cations and molecule additives can lead to high-quality organic–inorganic hybrid perovskite films, this method cannot be applied to CsPbI 3 thin films due to the absence of hydrogen bonds between Cs + ions and additives. In this study, an amorphous complex-seed-crystal growth process to fabricate high-quality γ -CsPbI 3 cuboid crystallite thin films, is reported. During the initial annealing, the metastable intermediates formed crystal nucleate seeds and transformed into amorphous complex intermediates, maintaining stability at an elevated temperature for perovskite crystallization. With prolonged annealing, the amorphous complex around the nucleate seeds gradually converts to γ -CsPbI 3 perovskite, enabling us to fabricate CsPbI 3 thin films with high crystallinity and orientation. The resulting deep-red LEDs exhibit a peak external quantum efficiency (EQE) of 16.5% and a high maximum luminance of 3158 cd m −2 . Moreover, the devices show significantly suppressed efficiency roll-off, maintaining an EQE of 14.8% even under a high current density of 500 mA cm −2 .
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2024
·
IF 7.7
Lei Zhang,Jie Zhang,Chao Lv,Li Gao,Shupin Luo,Yiping Ren,Liang Chang,Xueqi Chen,Qiheng Tang,Wenjing Guo
The primary purpose of this work is to study the fabrication of a flexible natural cellulosic fiber composite. In this respect, natural cellulosic fiber was obtained by modified poplar wood fiber through sodium hydroxide (NaOH) and γ-Aminopropyl Triethoxysilan. Then, the composites were fabricated by hot-pressing the modified wood fibers and polyurethane following characterization. Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and scanning electron microscope (SEM) observation results confirmed that some of the hemicellulose and lignin were removed from wood fibers after NaOH modification and successfully grafted with alkoxy structures after KH550 modification. NaOH&KH550 modification improved the interfacial compatibility between poplar wood fibers and polyurethane. The flexibility of the composites was improved (the slenderness value was reduced by 113 %), allowing flexible deformations such as bending, twisting, and knotting. In addition, thermal stability , tensile strength (increased by 105 %), elongation at the break (increased by 125 %), and water resistance were increased. This flexible natural cellulosic fiber composite is expected to be applied in the veneering of curved materials and special-shaped structure furniture, providing a theoretical basis for improving the added value of wood-based composites.
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FOOD HYDROCOLLOIDS
·
2024
·
IF 11
Junwei Qin,Litong Liu,Chengdu Miao,Bifeng Lan,Tao Liao,Xiaofei Tian,Zhenqiang Wu
Irradiation can promote the cross-linking of collagen to enhance its biological properties, but the molecular changes in irradiated collagen have few been investigated. This study aimed to explore the impact of irradiation treatment on the molecular structure stabilization and cross-linking degree of skin collagen. The results showed that collagen in solution was more susceptible to Co-60 gamma irradiation than that in fish skin and in sponge forms. The solubility of collagen in solution decreased by more than 80% and the carbonyl content increased by more than 4 times compared with the control group after 12 kGy irradiation. Spectroscopic analysis and sodium dodecyl sulfate - polyacrylamide gel electrophoresis (SDS-PAGE) showed that collagen in solution was cross-linked, especially at high irradiation doses. However, the triple helical structure of skin collagen and collagen sponge remained intact. Furthermore, irradiation also reduced the sensitivity of collagen to collagenase. Gastrointestinal digestion results showed that the antioxidant activity of collagen increased at 1–3 kGy doses and decreased at 9–12 kGy doses. Collagen irradiated at high doses (9–12 kGy) was more difficult to digest and had a larger average particle size. This study provides a potential new approach for the preparation of stable fishery-derived collagen with excellent antioxidant activity and resistance to digestion by irradiation treatment.
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2024
·
IF 7.7
Shuo Wang,Guochao Xu,Ye Ni
A novel carbonyl reductase from Hyphopichia burtoni ( Hb KR) was discovered by gene mining. Hb KR is a NADPH-dependent dual function enzyme with reduction and oxidation activity belonging to SDR superfamily. Hb KR strictly follows Prelog priority in the reduction of long-chain aliphatic keto acids/esters containing remote carbonyl groups, such as 4-oxodecanoic acid and 5-oxodecanoic acid, producing ( S )- γ -decalactone and ( S )- δ -decalactone in >99 % e.e. Tailor-made engineering of Hb KR was conducted to improve its catalytic efficiency . Variant F207A/F86M was obtained with specific activity of 8.37 U/mg toward 5-oxodecanoic acid, which was 9.7-fold of its parent. Employing F207A/F86M, 100 mM 5-oxodecanoic acid could be reduced into optically pure ( S )- δ -decalactone. Molecular docking analysis indicates that substitution of aromatic Phe with smaller residues renders sufficient space for accommodating substrates in a more stable conformation. This study offers an efficient biocatalyst for the biosynthesis of ( S )-lactones, and provides guidance for engineering carbonyl reductases toward structurally hindered substrates.
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BIOSCIENCE REPORTS
·
2024
·Vol. 44
·期 6
·
IF 3.8
Hao Xiao Hua,Liu Ke Xin,Zhang Meng Yuan
Increasing cadmium (Cd) pollution has negative effects on quinoa growth and production. Gamma-aminobutyric acid (GABA) confers plants with stress resistance to heavy metals; however, the mechanism remains unclear. We explored the effects of exogenous GABA on the physiological characteristics, antioxidant capacity, and Cd accumulation of quinoa seedlings under Cd stress using hydroponic experiments. Partial least-squares regression was used to identify key physical and chemical indices of seedlings affecting Cd accumulation. Compared with those of the CK group, exposure to 10 and 25 µmol·L−1 Cd significantly reduced the photosynthetic pigment contents, photosynthesis, and biomass accumulation of quinoa seedlings; resulted in shorter and thicker roots; decreased the length of the lateral roots; decreased the activities of superoxide dismutase (SOD) and peroxide (POD); and increased H2O2 and malondialdehyde (MDA) contents. Exogenous GABA reduced the Cd content in the stem/leaves and roots of quinoa seedlings under Cd stress by 13.22–21.63% and 7.92–28.32%, decreased Cd accumulation by 5.37–6.71% and 1.91–4.09%, decreased the H2O2 content by 38.21–47.46% and 45.81–55.73%, and decreased the MDA content by 37.65–48.12% and 29.87–32.51%, respectively. GABA addition increased the SOD and POD activities in the roots by 2.78–5.61% and 13.81–18.33%, respectively, under Cd stress. Thus, exogenous GABA can reduce the content and accumulation of Cd in quinoa seedlings by improving the photosynthetic characteristics and antioxidant enzyme activity and reducing the degree of lipid peroxidation in the cell membrane to alleviate the toxic effect of Cd stress on seedling growth.
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