JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY
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2018
·Vol. 18
·期 10
·6928-6933
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IF 1.354
Huynh Tai Thien,Van Nguyen At,Pham Hau Quoc,Vinh Nguyen Huu,Bach Long Giang,Thanh Ho Van Thi
Non-carbon materials are considered as the promising candidates for carbon-based catalyst support to increase the durability of proton exchange membrane fuel cells (PEMFCs). Due to the high stability and good electrical conductivity of TiO2, M-doped TiO2 (M is
transition metals: Mo, Ru, V, W) is an emerging candidate for Pt nanoparticles support on the cathode side of PEMFCs. In this research, the synthesis mechanism of Ti0.7Ir0.3O2 nanostructure by the one-step hydrothermal method at low temperature was studied.
We found that by only controlling the pH of the precursor solution, Ti0.7Ir0.3O2 can be synthesized with different morphology and phase selection without any formation of mixed oxides. In particular, Ti0.7Ir0.3O2 nanostructure
synthesized at pH = 0 exhibited concomitant anatase, brookite, and rutile phases. The spherical particles of diameter 20–40 nm, cubic particles of 30–50 nm in side-length and rod-like particles with 70 nm in length and 20 nm in diameter represented the anatase, brookite, and rutile
phases respectively. At a pH value of 1 or 2, the majority of spherical nanoparticles were homogeneous at 15–20 nm in diameter. It was observed that the electronic conductivity of novel Ti0.7Ir0.3O2 nanostructure was significantly higher than that of
the undoped TiO2. Thus the promising properties of this new nanostructure open a new path to the much-needed fuel cell applications.
研究领域:
材料科学
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燃料电池
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化学工程
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY
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2017
·Vol. 93
·期 6
·1618-1626
·
IF 3.135
Sheng-Jie Yue,Muhammad Bilal,Shu-Qi Guo,Hong-Bo Hu,Wei Wang,Xue-Hong Zhang
BACKGROUND Trans -2, 3-dihydro-3-hydroxyanthranilic acid (DHHA) is a valuable metabolic intermediate for the biosynthesis of wide-ranging benzoic acid derivatives with enormous biological or pharmaceutical activities. Pseudomonas chlororaphis GP72 is a non-pathogenic biocontrol strain that displays unique capability to produce phenazines. Nevertheless, DHHA production is quite low by the wild type strains, which necessitates yield improvement by constructing engineered strains for large-scale biotechnological applications. RESULTS In this study, two negative regulatory genes namely rsmE and lon were successively deactivated in the DA4 strain. The resulting engineered DA6 strain produced a significantly high titer of DHHA (20.6% higher than that of DA4). The influence of varying pH from 6.2 to 8.2 on DHHA production was studied in a 6-L benchtop fermenter. A controlled broth pH of 7.2 stimulated maximum DHHA production by the engineered DA6 strain. A DO-stat based fed-batch system maintaining a constant DO level (about 20%) accompanied by a glycerol feeding strategy was applied. Highest DHHA production using this approach was recorded to be 10.06 g L -1 , which was 31% higher than with traditional batch cultivation. CONCLUSION The production of DHHA in metabolically engineered GP72 was considerably improved by inactivating two negative regulatory genes in a fed-batch mode. It is concluded that fed-batch fermentation with intermittent glycerol feeding and pH-control was an effective approach to improve DHHA production yield. © 2017 Society of Chemical Industry
研究领域:
微生物学
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生物技术
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代谢工程
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DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2019
·
IF 8.355
Boyang Wu,Caiping Liu,Chengyu Fu,Pan Wu,Changjun Liu,Wei Jiang
The recovery and separation of vanadium and chromium from vanadium-containing chromate solution are necessary and valuable for the comprehensive utilization and environmental protection of V-Ti-bearing magnetite ore. In this work, a tetragonal ZrO 2 adsorbent was used for harmless treatment and resource reuse of a low-concentration vanadium-containing chromate solution. Results confirmed that water after treatment met the wastewater discharge standard; in addition, Cr(VI) and V(V) were efficiently separated with the V/Cr separation coefficient of 362.05 for the pH of 3.5 and the V/Cr ratio of 1:1 at the concentration of 80 mg/L. This excellent and stable separation performance of ZrO 2 was ascribed to the competitive adsorption of V(V) and Cr(VI) on ZrO 2 , owing to the strong effect of pH on their adsorption and desorption behavior. V(V) and Cr(VI) in vanadium-containing chromate solution can be removed, recovered, separated and enriched through a two-step adsorption/desorption process. The purity of vanadium and chromium can reach more than 99.8%. The adsorption of vanadium and chromium by ZrO 2 has high application value, which is beneficial to the recovery of resources and environmental protection.
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 SOLUTION CHEMISTRY
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2018
·Vol. 47
·期 6
·1037-1047
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IF 1.401
Gao Jing,Liu June,Wei Yuanyi,Nie Fanghong,Ji Hongwu
Ionic liquids (ILs) based aqueous biphasic systems (ABSs) have been successfully applied to the extraction and purification of biomolecules. Although much research has focused on the effect of ILs on the phase formation, there are few reports that describe the phase behavior of quaternary IL-based ABS systems using amino acids (AAs) as additives. Here, 1-butyl-3-methylimidazolium tetrafluoroborate ([C 4 mim]BF 4 ) formed an ABS with sodium citrate (Na 3 C 6 H 5 O 7 ) with the aid of AAs. The phase behavior and physical properties of the ABS were investigated at 298 K. The capacity of the AA to create the ABS (area of biphasic region) increases with increasing in solubility and decrease with the molecular weight of the ILs and follows the trend glycine > l -alanine ≈ l -lysine > l -threonine > l -proline ≈ l -arginine > none. Moreover, the pH of the top and bottom phases containing l -proline as additive are nearly neutral; l -threonine, glycine, and l -alanine result in mildly acidic environments, while l -arginine and l -lysine provide basic pH conditions. The results show that the effects of the addition of the AAs can be considerable and important in the simulation, design calculation and pH control of ABS for efficient separation and extraction processes.
研究领域:
生物化学
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分离科学
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产品关联
DOI
高影响因子
JOURNAL OF GENERAL AND APPLIED MICROBIOLOGY
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2016
·
IF 1
Alei Zhang,Cong Gao,Kequan Chen,Ce Wei,Pingkai Ouyang
The pH of a microbiological culture is important for both cell growth and chitinase accumulation, but the optimal pH is not normally the same for both. The objective of this study was to investigate the effect of pH on chitinase production by Chitinolyticbacter meiyuanensis strain SYBC-H1 (ATCC BAA-2140) in a mineral medium. The results of batch culture at different pH values showed that the optimum pH for cell growth and chitinase production varied with time, although KOH produced the best results for cell growth and chitinase production, NaOH was chosen because of cost considerations. We designed a three-stage pH control strategy using NaOH as the neutralizing agent. Maximum cell growth (1.07 g dry cell weight/l) and maximum chitinase activity (13.6 U/ml) were observed after culture at 26°C for 72 h in a mineral medium. These values were greater by 129% and 162%, respectively, and the length of time to attain maximum chitinase activity was decreased by 12 h, compared with results from an earlier study (Hao et al., 2011b).
研究领域:
微生物学
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生物技术
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DOI
PubMed
高影响因子
RSC Advances
·
2015
·Vol. 5
·期 26
·20595-20602
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IF 3.84
Genhua Wu,Chen Dong,Yonglong Li,Zhuqing Wang,Yuexia Gao,Zheyu Shen,Aiguo Wu
In this study, we propose a new silver nanoparticles (AgNPs)-based colorimetric sensor for rapid detection of Cu2+ or Mn2+ at pH 1.9 or 12.0, respectively. At pH 1.9, the AgNPs stabilized with sodium pyrophosphate (Na4P2O7) and hydroxypropylmethylcellulose (HPMC) gradually become smaller in the presence of Cu2+ resulting in a color change of the solution from yellow to colorless. At pH 12.0, however, the AgNPs aggregate immediately in the presence of Mn2+, which induces a color change of the solution from yellow to brown. The incubation time between the detection system and metal ion (Cu2+ or Mn2+) is fixed at 10 min. This mechanism is confirmed using UV-vis spectroscopy, Transmission electron microscopy (TEM), Dynamic light scattering (DLS) and Fourier-Transform Infrared Spectrometry (FT-IR). At the optimized experimental conditions, the selectivity of our AgNPs-based detection system is excellent for Cu2+ or Mn2+ compared with other metal ions. The limit of detections (LODs) of Cu2+ and Mn2+ by the naked eye are respectively 0.05 and 0.5 μM, and those by UV-vis spectroscopy are respectively 2.0 and 20 nM. The above LODs are all lower than the corresponding national drinking water standards (16 μM of Cu2+ and 1.8 μM of Mn2+). The applicability of our AgNPs-based colorimetric sensor is also validated by detection of Cu2+ and Mn2+ in tap water and lake water. Therefore, these results reinforce that our AgNPs-based colorimetric sensor is applicable to rapid colorimetric detection of Cu2+ and Mn2+ in complicated real water samples with excellent selectivity and high sensitivity.
研究领域:
分析化学
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环境科学
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纳米技术
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产品关联
DOI
高影响因子
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
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2018
·Vol. 124
·期 6
·1-12
·
IF 1.604
Wang Qian,Wu Jianning,Meng Guihua,Wang Yixi,Liu Zhiyong,Guo Xuhong
The wetting materials with the ability of controllable oil/water separation have drawn more and more public attention. In this article, the novel cotton fabric (CF) with pH controlled wettability transition was designed by a simple, environmentally friendly coating copolymer/SiO 2 nanoparticles, poly(heptadecafluorodecyl methacrylate- co -3-trimethoxysilylpropyl methacrylate- co -2-vinilpiridine) (PHDFDMA- co -PTMSPMA- co -P2VP). Furthermore, the structures and morphologies of coated CF were confirmed by Fourier transform infrared spectroscopy (FTIR), NMR, GPC, scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The coated CF exhibits switchable wettability between superhydrophobicity and superhydrophilicity via adjusting pH value. When the coated CF is placed in the neutral aqueous (pH = 7.0), it is superhydrophobic in the air and superoleophilic. It allows oil to go through but blocking water. However, in acidic aqueous environment (pH = 3.0), it turns superhydrophilic and underwater superoleophobic, which allows water to penetrate but blocking oil. Therefore, the coated CF could be applied to separate oil/water mixtures, ternary oil/water/water mixtures continuously and different surfactant stabilized emulsions (oil-in-water, water-in-oil) and displays the superior separation capacity for oil–water mixtures with a high efficiency of 99.8%. Moreover, the cycling tests demonstrate that the coated CF possesses excellent recyclability and durability. Such an eminent, controllable water/oil permeation feature makes coated CF could be selected as an ideal candidate for oil/water separation.
研究领域:
材料科学
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环境科学
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产品关联
DOI
高影响因子
ACS Sustainable Chemistry & Engineering
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2015
·
IF 4.642
Yuehua Chen,Huiyong Wang,Yuanchao Pei,Jiao Ren,Jianji Wang
The recovery of rare-earth metals from waste materials is very important due to the risks associated with having a low supply of them in the future. In this work, hydrophobic 1-alkylcarboxylic acid-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ionic liquids, [(CH2)nCOOHmin][Tf2N] (n = 3, 5, 7), were synthesized and used to separate neodymium (III) from Fe(III) and samarium (III) from Co(II) in aqueous solutions. The factors affecting the solvent extraction process such as phase volume ratio, contact time, pH value of the aqueous phase, alkyl chain length of the ionic liquids, and temperature of the system were examined systematically. It was found that the maxmium extraction efficiency of the investigated metal ions was as high as 99%, and Sm(III) and Nd(III) could be selectively separated from Co(II) and Fe(III), with separation factors of 104–105, by simply modulation of the aqueous phase pH. After extraction, about 97% of the metal ions could be stripped from ionic liquid phase in a single stripping step by using dilute aqueous HCl or oxalic acid, and the ionic liquids would be recovered and reused in the next extraction process. These results indicate that the ionic liquids developed here are useful for the selective recovery of rare-earth metals from NdFeB and SmCo permanent magnets.
研究领域:
材料科学
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环境科学
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产品关联
DOI
高影响因子
CHINESE JOURNAL OF CHEMISTRY
·
2022
·Vol. 40
·期 9
·1045-1052
·
IF 5.56
Kui Wang,Guo-Jie Gao,Xiao-Yan Wang
Comprehensive Summary In this work, a spherical calixpyridinium–IR-820 supramolecular assembled material was fabricated based on the calixpyridinium- induced IR-820 aggregation. This assembled material exhibited a well visible light responsiveness by the photodecomposition of aggregated IR-820 accompanied by an obvious color change. Such photochromic material has many potential applications. More interestingly, the photodecomposition of aggregated IR-820 was significantly promoted, although the aggregated photosensitizers usually exhibited a lower photoreactivity. This approach can be further extended to construct various visible-light responsive supramolecular assembled materials and potentially applied in many fields. Herein, benefitting from the pH-dependent luminescent properties of calixpyridinium and the photodegradation products of IR-820, a pH-controlled visual multicolor luminescence was achieved, which was perfectly applied in the detection of pH from 5 to 10 by naked eyes.
研究领域:
化学
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材料科学
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光学
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产品关联
DOI
高影响因子
DRUG DELIVERY
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2020
·
IF 4.902
Chunyun Wang,Peilan Qi,Yan Lu,Lei Liu,Yanan Zhang,Qianli Sheng,Tianshun Wang,Mengying Zhang,Rui Wang,Shiyong Song
The Editors and Publisher of the journal Drug Delivery, have retracted the following article:Chunyun Wang, Peilan Qi, Yan Lu, Lei Liu, Yanan Zhang, Qianli Sheng, Tianshun Wang, Mengying Zhang, Rui Wang & Shiyong Song (2020) Bicomponent polymeric micelles for pH-controlled delivery of doxorubicin, Drug Delivery, 27:1, 344–357, DOI: 10.1080/10717544.2020.1726526Since publication, concerns have been raised about the integrity of the data in the article. When approached for an explanation, the authors have been unable to fully address the concerns raised. As verifying the validity of published work is core to the integrity of the scholarly record, we are therefore retracting the article. All authors listed in this publication have been informed.We have been informed in our decision-making by our policy on publishing ethics and integrity and the COPE guidelines.The retracted article will remain online to maintain the scholarly record, but it will be digitally watermarked on each page as ‘Retracted’.
研究领域:
药学
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生物材料
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肿瘤治疗
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DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Ruoyu Dai,Xipao Chen,Ning Ouyang,Yaoping Hu
Carbon dots (CDs) with tunable photoluminescence (PL), especially with long wavelength PL , offer great potential for various applications including sensing, bioimaging, photomedicine, and optoelectronic devices. Here, we use 2,3-diaminopyridine as a single precursor to synthesize colorful CDs in different pH conditions. By simply regulating the reaction media from alkali to neutral to acid, bright CDs emitting violet, green, and orange fluorescence are prepared, respectively. Detailed characterizations reveal that the red-shift of PL is caused by the growing size of sp 2 conjugated domain and increasing content of graphite nitrogen. We embed CDs in starch to suppress self-quenching and enhance the PL quantum yields. The CD/starch composites, possessing efficient solid-state fluorescence, can be coated on the ultraviolet chips (365 nm) to fabricate multicolor light-emitting diodes toward indoor illumination. This work presents a new strategy to adjust the PL wavelength of CDs in a wide range, and clarifies the emission mechanism.
研究领域:
材料科学
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光学
·
化学
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DOI
高影响因子
ACS Catalysis
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2022
·
IF 13.7
Shuchao Jiang,Junxia Yang,Shengliang Zhai,Ling Zhang,Rui Tu,Tie Yu,Dong Zhai,Lei Sun,Weiqiao Deng,Guoqing Ren
Formic acid (FA)/formate as a promising liquid organic hydrogen carrier exhibits great potential for future energy supplies. However, FA/formate-based hydrogen storage and release, which can be operated under ambient conditions, is challenging but attractive. Here, we report an ambient hydrogen storage and release process that uses the acidity and alkalinity of the reaction solution to control hydrogen production or consumption via an l-arginine-functionalized active carbon-supported PdAu alloy catalyst (PdAu/AC-LA). By regulating the LA loading and Pd/Au ratio, we obtain the optimal catalytic activity with turnover frequency (TOF) of 1760 h–1 for FA dehydrogenation under acidic conditions and 138 h–1 for CO2 hydrogenation under alkaline conditions. Comprehensive characterizations, including X-ray photoelectron spectroscopy (XPS), CO2 temperature-programmed desorption (CO2-TPD), and HCOO– adsorption experiments, reveal that the synergistic effect between PdAu alloy and strongly basic l-arginine enhances catalytic activity by regulating the adsorption of reactants. Our work, as a successful example of FA/formate-based hydrogen storage and release under ambient conditions, may aid putting the safe and energy-saving use of hydrogen into practice.
研究领域:
化学工程
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催化科学
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能源技术
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DOI
高影响因子
危险品化学品经营许可证（带存储）