Materials
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2018
·Vol. 12
·期 1
·83
·
IF 2.467
Anping Wang,Hu Li,Heng Zhang,Hu Pan,Song Yang
The search for acid-base bifunctional catalysts has become a hot topic in the preparation of biofuels from renewable resources. In the present work, a series of novel acid-base bifunctional metal-boron catalysts were successfully prepared by a sol-gel method and characterized by XRD, IR, SEM, TEM, TGA, BET, and TPD. Among those bifunctional solid materials, the Ca-B(700) catalyst had the highest density of both acid and base sites and showed excellent catalytic performance in the production of biodiesel from nonedible oils with high acid value. Under the optimal reaction conditions of 20/1 methanol/oil mole ratio and 4 wt % catalyst dosage at 105 °C for 2 h, a high biodiesel yield of 96.0% could be obtained fromJatrophacurcas oil in one-pot. In addition, Ca-B(700) was also applicable to producing biodiesel fromFirmiana platanifolia L.f.oil in a relatively low acid value, with an almost quantitative yield (98.5%) at 65 °C after 2 h. The Ca-B(700) catalyst had good stability and reusability, which is a promising acid-base bifunctional catalytic material for the preparation of biodiesel.Keywords:sol-gel synthesis;acid-base bifunctional materials;high/low acid value oils;transesterification;biofuels
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Inorganic Chemistry Frontiers
·
2018
·Vol. 5
·期 10
·2657-2665
·
IF 5.106
Hongwei Pang,Yihan Wu,Shuyi Huang,Congcong Ding,Shun Li,Xiangxue Wang,Shujun Yu,Zhongshan Chen,Gang Song,Xiangke Wang
In the past few decades, uranium (235, 238U(VI)) has turned into a forefront environmental issue due to its extensive use in the nuclear industry and its toxicity and radioactivity. Herein, nanoscale zero valent iron (nZVI), which was supported on Ca–Mg–Al-layered double hydroxide (Ca–Mg–Al-LDH/nZVI), was fabricated via an in situ growth route and employed for U(VI) decontamination from aqueous solutions. Spectroscopy and microscopy (SEM, TEM, FTIR, XRD, BET, and XPS) technologies were applied for the investigation of the properties of Ca–Mg–Al-LDH/nZVI and the U(VI) elimination mechanism. Ca–Mg–Al-LDH/nZVI had a remarkable BET surface (426.8 m2 g−1), abundant functional groups (i.e., Fe–O, Al–O, –OH, etc.), high efficiency (4 h to achieve equilibrium) and large adsorption capacities (Qmax = 216.1 mg g−1) for U(VI) removal. The decontamination process of U(VI) was observed to be pH-dependent and ionic strength-independent, suggesting that the adsorption was predominated by inner-sphere surface coordination. XPS spectroscopy analyses indicated that the reduction and adsorption of nZVI and the adsorption of Ca–Mg–Al-LDH dominated U(VI) elimination on Ca–Mg–Al-LDH/nZVI. The environmentally friendly synthesis method, excellent physicochemical properties and remarkable removal performance suggested that Ca–Mg–Al-LDH/nZVI was applicable as a potential adsorbent for U(VI) decontamination from wastewater in environmental pollution remediation.
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FOOD HYDROCOLLOIDS
·
2014
·
IF 4.28
Sha Cai,Meng Zhao,Yapeng Fang,Katsuyoshi Nishinari,Glyn O. Phillips,Fatang Jiang
Emulsification/internal gelation is an effective encapsulation method to protect probiotics from adverse environment. In this paper, microcapsules of Lactobacillus acidophilus CGMCC1.2686 were prepared by emulsification and gelation of alginate solutions with slow release of Ca 2+ ions from calcium carbonate (CaCO 3 ) and calcium disodium ethylenediaminetetraacetate (Ca-EDTA). Physical characterization of the two types of microcapsules showed that alginate-Ca-EDTA microcapsule was more uniform in size than alginate-CaCO 3 , with a span factor of 0.96 and 1.20, respectively. Mechanical measurements demonstrated that alginate-CaCO 3 microcapsule was more robust and elastic, which was supported by its denser structure as observed by electron scanning microscopy. Bacteria encapsulation yields in the two microcapsules were similar, 37.9% for alginate-CaCO 3 and 36.9% for alginate-Ca-EDTA. However, alginate-CaCO 3 microcapsule exhibited much higher cell survivals in both simulated gastric juice and bile salts solution (22.2% and 2.6*10 −2 %, respectively) than alginate-Ca-EDTA (7.1% and 0%, respectively), indicating a more effective protection of L. acidophilus CGMCC1.2686. The protection efficiency was discussed in relation to the mechanical properties of the microcapsules and the calcium sources used.
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Chemical Engineering and Processing-Process Intensification
·
2024
·
IF 3.8
Muhammad Umair Mushtaq,Zhu Lin,Danni Li,Khurram Shahzad Ayub,Zain Abbas,Waqas Qamar Zaman,Ji Yang
The oxygen reduction reaction (ORR) is fundamental in numerous electrochemical energy conversion technologies, necessitating efficient catalysts to enhance reaction kinetics and reduce precious metal usage. This study focuses strategic clustering of Pt-Ni on Calcium Oxide/activated carbon (C/Ca) aerogels. Electrochemical analyses confirmed that incorporating Ni into Pt matrices significantly enhanced ORR activities with Pt 25 Ni 75 -C/Ca composition emerged as optimum. A positive shift in half-wave potential (905 mV vs. RHE) and impressive mass activity (72.50 Ag −1 at 85 V) highlight the potential of this composite as a highly effective and stable ORR catalyst. Pt-C/Ca demonstrated performance fluctuation, while Pt 25 Ni 75 -C/Ca showed remarkable stability after 40,000 cycles. Furthermore, C/Ca aerogels exhibited a significantly increased BET surface area, and the presence of Pt-Ni/pyridinic-N species on its surface C/Ca aerogel provided supplementary active sites that facilitated the adsorption and reduction of O 2 during ORR.
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Journal of Cleaner Production
·
2017
·
IF 5.715
De-Bin Li,Yun-Quan Liu,Yue-Yuan Ye,Shui-Rong Li,Duo Wang
Experiments were conducted to elucidate the mechanism of reaction between guaiacol and Ca(OH) 2 in water based on in situ FT-IR, 1 H NMR, ICP-AES and TGA analyses. Three phases were revealed for this reaction when guaiacol was dropped into the solution of Ca(OH) 2 , and the final molar ratio of guaiacol to Ca 2+ reaches 4. It was found that an acid–base reaction occurs in the first reaction phase. However, the second reaction phase includes not only the acid-base reaction, but also the accompanied coordination reaction between oxygen atom of hydroxyl group in guaiacol and Ca 2+ . The third reaction phase is also the coordination reaction, particularly, the one between the hydrogen atom in guaiacol and Ca 2+ . Based on the mechanism study, a novel circulating precipitation agent was developed and tested for the extraction of phenolic compounds from the simulated wastewater. The result showed that 96.63% guaiacol could be extracted from the simulated wastewater with the novel extraction technology at the optimum reaction conditions.
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2024
·
IF 7.7
Liwen Shen,Feiyang Zhao,Huijuan Liu,Jicheng Li,Yang Lu,Jun Liu,Nianzhao Gao,Shuangfei Xiang,Shujun Zhao,Guocheng Zhu,Parpiev Khabibulla,Juramirza Kayumov,Feiya Fu,Xiangdong Liu
The agricultural industry produces a substantial volume of rice straw (RS) annually, highlighting the importance of recycling RS for sustainable materials. However, the poor interfacial compatibility between RS and polymers often leads to drawbacks in their composites, such as water-swelling and limited tensile strength. Here, we propose a novel approach using Ca(OH) 2 that offers several distinct advantages: enhancement of interfacial compatibility, elimination of the need for water washing, and formation of calcified hybrid particles on fiber surfaces by capturing CO 2 from the atmosphere. The non-washing calcified rice straw (NCRS) fibers were used to fabricate composites with unsaturated polyester resin (UPR), resulting in NCRS/UPR composites exhibiting significant enhancements in water resistance and mechanical properties compared to RS/UPR composites. The NCRS/UPR composites achieved a water absorption rate below 25 %, thickness swelling rate below 10 %, and tensile strength of 19.9 MPa. This work comprehensively explored the mechanism underlying these achievements through experimental studies. Findings suggest that CaCO 3 particles involving with released lignin act as an interfacial bridge between RS fiber surface and UPR, resulting in significantly improved properties. This approach demonstrates promising prospects as a simple and eco-friendly methodology for manufacturing RS-based composite materials.
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JOURNAL OF HAZARDOUS MATERIALS
·
2017
·
IF 6.065
Haijun Chen,Zhe Chen,Guixia Zhao,Zhibin Zhang,Chao Xu,Yunhai Liu,Jing Chen,Li Zhuang,Tasawar Haya,Xiangke Wang
Ca/Al layered double hydroxide decorated carbon nanotube (Ca/Al-LDH@CNTs) composites were fabricated by co-precipitation method and hydrothermal aged treatment. The prepared Ca/Al-LDH@CNTs was characterized by SEM, TEM, EDS, XRD, FT-IR, UV–vis and XPS techniques, and applied to remove U(VI) from aqueous solutions under various environmental conditions (i.e., pH, ionic strength, temperature and contact time). The results indicated that the adsorption of U(VI) on Ca/Al-LDH@CNTs was four times higher than that of U(VI) on bare CNTs. The kinetic investigations reflected the chemisorption of U(VI) on Ca/Al-LDH@CNTs through oxygen-containing functional groups. The adsorption isotherms demonstrated that the adsorption of U(VI) was well fitted by Langmuir model and the maximum adsorption capacity of U(VI) on Ca/Al-LDH@CNTs was calculated to be 382.9 mg g −1 at 289.15 K. The thermodynamic parameters calculated from temperature-dependent isotherms suggested that U(VI) adsorption on Ca/Al-LDH@CNTs were endothermic and spontaneous process. Furthermore, Ca/Al-LDH@CNTs could remove ∼91% of 241 Am(III) at pH = 8.0, which confirmed Ca/Al-LDH@CNTs as a promising material for multiply low level radionuclides’ pollution remediation.
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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
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2024
·
IF 8.1
Jiajin Li,Minglei Lu,Yuxin Ge,Weiwei Lu,Zidi Liu,Hongde Xu,Yu Zhang,Zhihui Li,Zhuoyu Zheng,Pengxiang Gao,Qian Zhang,Tiejun Wang
Aqueous-phase reforming of methanol (APRM) is an important method for H 2 production, widely used in energy fields like polymer electrolyte membrane fuel cells (PEMFCs). However, traditional noble metal catalysts , being expensive and vulnerable to CO poisoning, restrict their practical application. Therefore, developing robust non-noble metal catalysts for efficient and sustainable H 2 production with low CO levels in APRM at low temperatures is highly significant. In this study, a novel approach was employed to synthesize carbon-encapsulated Cu catalyst via controlled pyrolysis , leading to Cu@CA-Val catalyst with excellent low-temperature catalytic activity. The optimal Cu@CA-Val-300 catalyst exhibited a high hydrogen production rate of 0.2–27.0 μmolH 2 /g cat /s over a wide temperature of 135–180 °C (base-free), surpassing the most Cu-based and Pt-based catalysts. The Cu@CA-Val-300 catalyst exhibited exceptional hydrothermal stability during continuous operation in a fixed reactor for 200 h. Efficient H 2 production was attributed to good wettability , enabling the diffusion of CH 3 OH and H 2 O molecules into Cu + /Cu 0 sites for activation, with CO being suppressed and transformed through the formate formation.
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SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
·
2025
·
IF 4.6
Dajie Zou,Chenyan Lu,Yanyan Jia,Huan Wang,Jiuli Wang
Histidine (His) plays an important role in human health and life activities. It will harm human health when His intake is insufficient or excessive. Its residue also will pollute the natural environment. Therefore, establishing a reliable and sensitive method for detecting histidine is particularly important. However, most of the existing detection methods of His rely on the single change of single signal, which are susceptible to interference from testing environmental factors and prone to generating false positive results. In contrast, the fluorescence and colorimetric dual-signal sensing system can not only effectively improve the reliability of detection, but also significantly reduce the risk of false positives. Therefore, the dual-signal sensing system has gradually become the research hotspot. Based on this, 5,10,15,20-tetra-(4-sulfophenyl) porphyrin (TSPP) was selected as the fluorescence and colorimetry dual-signal probe for the rapid detection of His in this study. Since TSPP could interact with many substances due to the specificity of molecular structure, it is the best choice to build an “ON-OFF-ON” sensing system in order to improve the specificity of the sensing system. Therefore, citric acid (CA) as an intermediate based on TSPP probe was successfully developed fluorescence and colorimetric dual-sensing system for the quantitative detection of histidine in real samples. The signal of the dual sensing system was “turned on” when the red TSPP solution obtained the fluorescence emission wavelength of 642 nm at the 514 nm optimal excitation wavelength and the UV–Vis absorption at 413 nm, respectively. The fluorescence intensity and absorbance of TSPP gradually decreased with the introduction of CA. At this time, the signal of the dual-sensing system became “turned off”, and the color of the solution changed from light pink to light green. The quenched fluorescence intensity and absorbance, however, was restored upon the introduction of histidine into the system. Simultaneously, the color of the solution changed from light green to light pink, and the dual-sensing system became “turned on”. Therefore, a novel fluorescence and colorimetric dual-signal sensing system based on TSPP was proposed for histidine detection. The results indicated that the linear ranges of the fluorescence sensing system were 8.34 × 10 −6 M − 1.51 × 10 −4 M and 1.85 × 10 −4 M − 1.4 × 10 −3 M with detection limits of 0.282 μM and 10.91 μM (LOD, S/N = 3), respectively. The linear range of the colorimetric sensing system was 2.04 × 10 −4 M–4.35 × 10 −4 M with a detection limit of 11.97 μM (LOD, S/N = 3). Meanwhile, the dual-sensing system provided a promising platform for practical samples sensing applications.
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PLoS One
·
2024
·Vol. 19
·期 9
·e0308424
·
IF 2.9
Yulin Liu,Longzhan Dong,Wenli Wu,Jiantao Ping,Jingbo Chen,Qiongzheng Hu
Hardness is one of the basic parameters of water, and a high-level hardness of drinking water may be harmful to human health. Thus, it is very important to monitor drinking water hardness. In this work, a portable lateral flow distance-based paper sensor for the semi-quantitative detection of drinking water hardness is demonstrated. In the presence of Ca 2+ /Mg 2+ , the hydrogel can be formed via the chelation between sodium alginate and Ca 2+ /Mg 2+ , inducing a phase separation process. The viscosity change of the sodium alginate solution is directly related to the Ca 2+ /Mg 2+ concentration and can be determined by the water lateral flow distance on test strips. The sensor successfully realizes the quantification of Ca 2+ and Mg 2+ in the range of 0–10 mmol L -1 and 4–20 mmol L -1 , respectively. The recoveries are found varied from 95% to 108.9%. The water hardness is acceptable for drinking if the C r values lies in the range of 0.259 to 0.419, and it is high with the C r value above 0.595. Remarkably, the performance of the sensor is comparable with the commercial kit for real water samples, which avoids the subjective judgment. Overall, this method provides a portable approach for semi-quantitative detection of drinking water hardness with the merits of convenience and low cost, which shows great potential for the potential application.
研究领域:
环境科学
·
分析化学
·
水质监测
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MATERIALS RESEARCH BULLETIN
·
2023
·
IF 5.4
Zhiwei Li,Zhengxiang Bian,Yurong Ren,Zhihui Chen,Jiujun Xu
(1-x)(0.9Ba 1.003 Ti 0.97 Ca 0.03 O 3 –0.1(Bi 0.51 Na 0.47 ) 0.94 Ba 0.06 TiO 3 )-xNa(Nb 0.85 Ta 0.15 )O 3 ( x = 0.03–0.15) ceramics were designed and fabricated through a bidirectional optimization strategy using traditional solid reaction method. The results revealed that the introduction of Na(Nb 0.85 Ta 0.15 )O 3 increased the vacancy concentration at the A site , conducing to improved polarization and reduced grain size. The substitution at the B site disrupted the long-range ordered ferroelectric domains and generated polar nanodomains, leading to enhanced relaxation behavior. The optimum energy storage density of 3.57 J/cm 3 and efficiency of 87.5% were simultaneously achieved under the electric field of 220 kV/cm in the sample with x = 0.09. Moreover, it also exhibits extremely high-power density (∼57 MW/cm 3 ), ultrafast discharge time (∼103 ns), high discharge density (1.35 J/cm 3 ), along with excellent temperature (30‒120 °C) and frequency stability (1‒100 Hz) under the equivalent electric field of 120 kV/cm. This novel design strategy provides theoretical guidance for the development of advanced electrical energy storage devices.
研究领域:
材料科学
·
能源存储
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Nanomaterials
·
2022
·Vol. 12
·期 16
·2755
·
IF 5.719
Yue Xu,Huan Liao,Jing Zhang,Haijun Lu,Xinghua He,Yi Zhang,Zhenbin Wu,Hongyu Wang,Minghua Lu
Recovery phosphorus (P) from P-contaminated wastewater is an efficient and environmentally friendly mean to prevent water pollution and alleviate the P shortage crisis. In this study, oyster shell as calcium sources and peanut shells as carbon sources (mass ratio 1:1) were used to prepare a novel Ca-modified biochar (OBC) via co-pyrolysis, and its potential application after P adsorption as a P biofertilizer for soil was also investigated. The results shown that OBC had a remarkable P adsorption capacity from wastewater in a wide range of pH 4–12. The maximum P adsorption capacity of OBC was about 168.2 mg/g with adsorbent dosage 1 g/L, which was about 27.6 times that of the unmodified biochar. The adsorption isotherm and kinetic data were better described by Langmuir isotherm model (R2> 0.986) and the pseudo second-order model (R2> 0.975), respectively. Characterization analysis of OBC before and after P adsorption by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and specific surface area and porosity analyzer (BET) indicated that the remarkable P adsorption capacity of OBC was mainly ascribed to chemical precipitation, electrostatic adsorption, and hydrogen bonding. Pot experiment results showed that OBC after P adsorption could significantly promote the germination and growth ofSpinacia, which manifested that OBC after P adsorption exhibited a good ability to be reused as P fertilizer for soil.Keywords:phosphorous;oyster shell;peanut shell;biochar;P biofertilizer
研究领域:
环境科学
·
农业科学
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