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Synthesis and characterization of magnesium hydroxide by batch reaction crystallization

Xingfu SONG, Shuying SUN, Dengke ZHANG, Jin WANG, Jianguo YU

《化学科学与工程前沿(英文)》 2011年 第5卷 第4期   页码 416-421 doi: 10.1007/s11705-011-1125-9

摘要: Magnesium hydroxide with high purity and uniform particle size distribution was synthesized by the direct precipitation method using MgCl and NaOH as reactive materials and NaCl as additive to improve the crystallization behavior of the product. The particle size distribution, crystal phase, morphology, and surface area of magnesium hydroxide were characterized by Malvern laser particle size analyzer, X-ray diffraction (XRD), scanning electron microscope (SEM) and Branauer-Emmett-Teller (BET) method, respectively. The purity of products was analyzed by the chemical method. The effects of synthesis conditions on the particle size distribution and water content (filtration cake) of magnesium hydroxide were investigated. The results indicated that feeding mode and rate, and reaction temperature had important effects on water content and the particle size distribution of the product, and sodium chloride improved the crystallization behavior of magnesium hydroxide. The ball-like magnesium hydroxides with the particle size distribution of 6.0–30.0 μm and purity higher than 99.0% were obtained. This simple and mild synthesis method was promising to be scaled up for the industrial production of magnesium hydroxide.

关键词: magnesium hydroxide     direct precipitation method     industrial crystallization     particle size distribution    

Noble-metal-free cobalt hydroxide nanosheets for efficient electrocatalytic oxidation

Jie Lan, Daizong Qi, Jie Song, Peng Liu, Yi Liu, Yun-Xiang Pan

《化学科学与工程前沿(英文)》 2020年 第14卷 第6期   页码 948-955 doi: 10.1007/s11705-020-1920-2

摘要: Cobalt hydroxide has been emerging as a promising catalyst for the electrocatalytic oxidation reactions, including the oxygen evolution reaction (OER) and glucose oxidation reaction (GOR). Herein, we prepared cobalt hydroxide nanoparticles (CoHP) and cobalt hydroxide nanosheets (CoHS) on nickel foam. In the electrocatalytic OER, CoHS shows an overpotential of 306 mV at a current density of 10 mA·cm . This is enhanced as compared with that of CoHP (367 mV at 10 mA·cm ). In addition, CoHS also exhibits an improved performance in the electrocatalytic GOR. The improved electrocatalytic performance of CoHS could be due to the higher ability of the two-dimensional nanosheets on CoHS in electron transfer. These results are useful for fabricating efficient catalysts for electrocatalytic oxidation reactions.

关键词: electrocatalytic oxidation     cobalt hydroxide     nanosheet     water     glucose    

Hierarchically porous cellulose nanofibril aerogel decorated with polypyrrole and nickel-cobalt layered double hydroxide

《化学科学与工程前沿(英文)》 2023年 第17卷 第10期   页码 1593-1607 doi: 10.1007/s11705-023-2348-2

摘要: With increasing emphasis on green chemistry, biomass-based materials have attracted increased attention regarding the development of highly efficient functional materials. Herein, a new pore-rich cellulose nanofibril aerogel is utilized as a substrate to integrate highly conductive polypyrrole and active nanoflower-like nickel-cobalt layered double hydroxide through in situ chemical polymerization and electrodeposition. This ternary composite can act as an effective self-supported electrode for the electrocatalytic oxidation of glucose. With the synergistic effect of three heterogeneous components, the electrode achieves outstanding glucose sensing performance, including a high sensitivity (851.4 µA·mmol−1·L·cm−2), a short response time (2.2 s), a wide linear range (two stages: 0.001−8.145 and 8.145−35.500 mmol·L−1), strong immunity to interference, outstanding intraelectrode and interelectrode reproducibility, a favorable toxicity resistance (Cl), and a good long-term stability (maintaining 86.0% of the original value after 30 d). These data are superior to those of some traditional glucose sensors using nonbiomass substrates. When determining the blood glucose level of a human serum, this electrode realizes a high recovery rate of 97.07%–98.89%, validating the potential for high-performance blood glucose sensing.

关键词: cellulose nanofibril     aerogel     nickel-cobalt layered double hydroxide     polypyrrole     nonenzymatic glucose sensor    

Layered double hydroxide-based core-shell nanoarrays for efficient electrochemical water splitting

Wenfu Xie, Zhenhua Li, Mingfei Shao, Min Wei

《化学科学与工程前沿(英文)》 2018年 第12卷 第3期   页码 537-554 doi: 10.1007/s11705-018-1719-6

摘要:

Electrochemical water splitting is an efficient and clean strategy to produce sustainable energy productions (especially hydrogen) from earth-abundant water. Recently, layered double hydroxide (LDH)-based materials have gained increasing attentions as promising electrocatalysts for water splitting. Designing LDHs into hierarchical architectures (e.g., core-shell nanoarrays) is one of the most promising strategies to improve their electrocatalytic performances, owing to the abundant exposure of active sites. This review mainly focuses on recent progress on the synthesis of hierarchical LDH-based core-shell nanoarrays as high performance electrocatalysts for electrochemical water splitting. By classifying different nanostructured materials combined with LDHs, a number of LDH-based core-shell nanoarrays have been developed and their synthesis strategies, structural characters and electrochemical performances are rationally described. Moreover, further developments and challenges in developing promising electrocatalysts based on hierarchical nanostructured LDHs are covered from the viewpoint of fundamental research and practical applications.

关键词: layered double hydroxides (LDHs)     core-shell nanoarrays     oxygen evolution reaction (OER)     hydrogen evolution reaction (HER)     photoelectrochemical water splitting (PEC)    

Defective Nickle–Iron Layered Double Hydroxide for Enhanced Photocatalytic NO Oxidation with Significant

Xiaoyu Li,Xiaoshu Lv,Jian Pan,Peng Chen,Huihui Peng,Yan Jiang,Haifeng Gong,Guangming Jiang,Li'an Hou,

《工程(英文)》 doi: 10.1016/j.eng.2023.06.017

摘要: Photocatalysis offers a sustainable avenue for the oxidative removal of low concentrations of NOx from the atmosphere. Layered double hydroxides (LDHs) are promising candidate photocatalysts owing to their unique layered and tunable chemical structures, and the abundant hydroxide (OH−) moieties on their surfaces that are hydroxyl radical (•OH) precursors. However, inferior charge separation and limited active sites on an LDH hinder its practical applications. Herein, we developed a facile N2H4-driven etching (et) approach that introduces dual Ni2+ and OH− vacancies (Niv and OHv) into NiFe-LDH nanosheets (referred to as NiFe-LDH-et) that facilitate improved charge-carrier separation and the formation of active Lewis acidic sites (Fe3+ and Ni2+ exposed at OHv). In contrast to inert pristine LDH, NiFe-LDH-et actively removes NO when illuminated with visible light. Specifically, Ni76Fe24-LDH-et etched in 1.50 mmol·L−1 N2H4 solution removes 32.8% of the NO from continuously flowing air (NO-feed concentration: ∼500 parts per billion (ppb)) when illuminated with visible light, thereby outperforming most reported catalysts. Experimental and theoretical data reveal that the dual vacancies promote the production of reactive oxygen species (•O2− and •OH) and the adsorption of NO on the LDH. In-situ spectroscopy revealed that NO is preferentially adsorbed at Lewis acidic sites, particularly exposed Fe3+ sites, and then converted into NO+ that is subsequently oxidized to NO3− without the formation of any of the more toxic NO2 intermediate, thereby alleviating risks associated with its production and emission.

关键词: Vacancies     Layered double hydroxide     NO     +     Photocatalysis     NO removal    

Crosslinking acrylamide with EDTA-intercalated layered double hydroxide for enhanced recovery of Cr(VI

Jing Li, Haiqin Yu, Xue Zhang, Rixin Zhu, Liangguo Yan

《环境科学与工程前沿(英文)》 2020年 第14卷 第3期 doi: 10.1007/s11783-020-1229-x

摘要: Functional groups of AM and EDTA in composite increased removal of Cr(VI) and CR. Removal process reached equilibrium within 30 min and was minimally affected by pH. Elimination of Cr(VI) was promoted by coexisting CR. Adsorption process of CR was less influenced by the presence of Cr(VI). Mechanisms were electrostatic attraction, surface complexation and anion exchange. We prepared ethylenediaminetetraacetic acid (EDTA)-intercalated MgAl-layered double hydroxide (LDH-EDTA), then grafted acrylamide (AM) to the LDH-EDTA by a cross-linking method to yield a LDH-EDTA-AM composite; we then evaluated its adsorptive ability for Congo red (CR) and hexavalent chromium (Cr(VI)) in single and binary adsorption systems. The adsorption process on LDH-EDTA-AM for CR and Cr(VI) achieved equilibrium quickly, and the removal efficiencies were minimally affected by initial pH. The maximum uptake quantities of CR and Cr(VI) on LDH-EDTA-AM were 632.9 and 48.47 mg/g, respectively. In mixed systems, chromate removal was stimulated by the presence of CR, while the adsorption efficiency of CR was almost not influenced by coexisting Cr(VI). The mechanisms involved electrostatic attraction, surface complexation, and anion exchange for the adsorption of both hazardous pollutants. In the Cr(VI) adsorption process, reduction also took place. The removal efficiencies in real contaminated water were all higher than those in the laboratory solutions.

关键词: Chromate     Dye adsorption     Simultaneous removal     Cross-linking method     Amino functionalization    

Utilization of aluminum hydroxide waste generated in fluoride adsorption and coagulation processes for

Jiawei JU,Ruiping LIU,Zan HE,Huijuan LIU,Xiwang ZHANG,Jiuhui QU

《环境科学与工程前沿(英文)》 2016年 第10卷 第3期   页码 467-476 doi: 10.1007/s11783-015-0809-7

摘要: Although Al-based coagulation and adsorption processes have been proved highly efficient for fluoride (F) removal, the two processes both generate large amount of Al(OH) solid waste containing F (Al(OH) -F). This study aimed to investigate the feasibility of utilizing Al(OH) -F generated in Al(OH) adsorption (Al(OH) -F ) and coagulation (Al(OH) -F ) for the adsorption of cadmium ion (Cd(II)). The adsorption capacity of Al(OH) -F and Al(OH) -F for Cd(II) was similar as that of pristine aluminum hydroxide (Al(OH) ), being of 24.39 and 19.90 mg·g , respectively. The adsorption of Cd(II) onto Al(OH) -F and Al(OH) -F was identified to be dominated by ion-exchange with sodium ion (Na ) or hydrogen ion (H ), surface microprecitation, and electrostatic attraction. The maximum concentration of the leached fluoride from Al(OH) -F and Al(OH) -F is below the Chinese Class-I Industrial Wastewater Discharge Standard for fluoride (<10 mg·L ). This study demonstrates that the Al(OH) solid wastes generated in fluoride removal process could be potentially utilized as a adsorbent for Cd(II) removal.

关键词: Al(OH)3     fluoride     cadmium     adsorption     reclamation     sequential extraction    

ALKALINE PRETREATMENT AND AIR MIXING FOR IMPROVEMENT OF METHANE PRODUCTION FROM ANAEROBIC CO-DIGESTION OF POULTRY LITTER WITH WHEAT STRAW

《农业科学与工程前沿(英文)》 2023年 第10卷 第3期   页码 424-436 doi: 10.15302/J-FASE-2023506

摘要:

● Integration of alkaline pretreatment and air mixing for co-digestion was validated.

关键词: sodium hydroxide     air injection     cumulative methane yield     kinetic modeling analysis     digestate    

Chemical mapping of cement pastes by using confocal Raman spectroscopy

Fengjuan LIU,Zhihui SUN

《结构与土木工程前沿(英文)》 2016年 第10卷 第2期   页码 168-173 doi: 10.1007/s11709-015-0323-9

摘要: In the present study, chemical mapping on the hydration process of cement paste with water-to-cement ( / ) ratio of 0.60 was implemented by Raman spectroscopy (RS). The RS was applied to study the paste from 12 hours after mixing to 28 days. Cement ingredients and hydration products, including calcium silicates (C S and C S), calcium hydroxide (CH), and ettringite, were quantitatively studied. From the research, it is observed that calcium silicates were consumed gradually with the increased hydration age. Calcium hydroxide increased and tended to cluster in the pore vicinity during hydration. Ettringite was found to form on the surface of the unreacted particles, which was shown as a mixed zone of ettringite and calcium silicates in the maps. It is concluded from the study that chemical mapping was an effective method to assist in visualizing particle dispersion and connection on top of the quantitative analysis.

关键词: chemical mapping     Raman spectroscopy     calcium silicates     calcium hydroxide     ettringite    

Performance of bioferric-submerged membrane bioreactor for dyeing wastewater treatment

ZOU Haiyan, XI Danli

《环境科学与工程前沿(英文)》 2007年 第1卷 第3期   页码 374-380 doi: 10.1007/s11783-007-0064-7

摘要: Adding iron salt or iron hydroxide to sludgemixed liquor in an aeration tank of a conventional activated sludge processes (bioferric process) can simultaneously improve the sludge s filterability and enhance the system s treatment capacity. In view of this, Fe(OH) was added to a submerged membrane bioreactor (SMBR) to enhance the removal efficiency and to mitigate membrane fouling. Bioferric process and SMBR were combined to create a novel process called Bioferric-SMBR. A side-by-side comparison study of Bioferric-SMBR and common SMBR dealing with dyeing wastewater was carried out. Bioferric-SMBR showed potential superiority, which could enhance removal efficiency, reduce membrane fouling and improve sludge characteristic. When volumetric loading rate was 25% higher than that of common SMBR, the removal efficiencies of Bioferric-SMBR on COD, dye, and NH-N were 1.0%, 9.5%, and 5.2% higher than that of common SMBR, respectively. The trans-membrane pressure of Bioferric-SMBR was only 36% of that in common SMBR while its membrane flux was 25% higher than that of common SMBR. The stable running period in Bioferric-SMBR was 2.5 times of that in common SMBR when there was no surplus sludge discharged. The mixed liquor suspended solids concentration of Bioferric-SMBR was higher than that of common SMBR with more diversified kinds of microorganisms such as protozoans and metazoans. The mean particle diameter and specific oxygen uptake rate of Bioferric-SMBR were 3.10 and 1.23 times the common SMBR, respectively.

关键词: hydroxide     surplus     aeration     SMBR     Bioferric process    

β-Nickel hydroxide cathode material for nano-suspension redox flow batteries

Yue LI, Cheng HE, Elena V. TIMOFEEVA, Yujia DING, Javier PARRONDO, Carlo SEGRE, Vijay RAMANI

《能源前沿(英文)》 2017年 第11卷 第3期   页码 401-409 doi: 10.1007/s11708-017-0496-0

摘要: As part of an effort to build a prototype flow battery system using a nano-suspension containing β-Ni(OH) nanoparticles as the cathode material, nano-sized β-Ni(OH) particles with well-controlled particle size and morphology were synthesized via the one-step precipitation of a NiCl precursor. The composition and morphology of the nanoparticles were characterized by scanning electronic microscopy (SEM) and X-ray diffraction (XRD). The XRD patterns confirmed that β-Ni(OH) was successfully synthesized, while SEM results showed that the particle sizes range from 70 to 150 nm. To ensure that Ni(OH) could be employed in the nano-suspension flow battery, the electrochemical performance of the synthesized β-Ni(OH) was initially tested in pouch cells through charge/discharge cycling. The phase transformations occurring during charge/discharge were investigated using X-ray absorption spectroscopy to obtain the shift in the oxidation state of Ni (X-ray adsorption near edge structure, XANES) and the distances between Ni and surrounding atoms in charged and discharged states (extended X-ray absorption fine structure, EXAFS). XANES results indicated that the electrode in the discharged state was a mixture of phases because the edge position did not shift back completely. XAFS results further proved that the discharge capacity was provided by β-NiOOH and the ratio between β-Ni(OH) and g-NiOOH in the electrode in the discharged state was 71:29. Preliminary nano-suspension tests in a lab-scale cell were conducted to understand the behavior of the nano-suspension during charge/discharge cycling and to optimize the operating conditions.

关键词: nano-suspension flow battery     β-Ni(OH)2     scanning electronic microscopy (SEM)     X-ray diffraction (XRD)     X-ray adsorption near edge structure (XANES)     extended X-ray absorption fine structure (EXAFS)    

碱式碳酸锌热分解机理及动力学

马正先,韩跃新,刘春生,郑龙熙,王泽红

《中国工程科学》 2003年 第5卷 第10期   页码 78-82

摘要:

采用TG、DTA、DTG等热分析手段研究了碱式碳酸锌热分解过程,热分析研究结果显示, Zn5(CO3)2·(OH)6为一步分解而得到纳米氧化锌,研究得到的机理模型证明其热分解过程符合随机核化机理。利用XRD,TEM等测试手段对纳米氧化锌的结构和形貌进行了表征,结果表明,通过Zn5(CO3)2·(OH)6热分解方法可以获得结晶性及分散性良好、粒径分布窄、粒度约为10nm左右的纳米氧化锌。

关键词: 纳米氧化锌     碱式碳酸锌     机理     动力学     热分解    

Thermal defluorination behaviors of PFOS, PFOA and PFBS during regeneration of activated carbon by molten salt

《环境科学与工程前沿(英文)》 2022年 第16卷 第8期 doi: 10.1007/s11783-022-1524-9

摘要:

• New method of mineralizing PFCs was proposed.

关键词: PFCs     Molten sodium hydroxide     Thermal degradation     Activated carbon regeneration    

Preparation and crystallization kinetics of micron-sized Mg(OH)

Xingfu SONG, Kefeng TONG, Shuying SUN, Ze SUN, Jianguo YU

《化学科学与工程前沿(英文)》 2013年 第7卷 第2期   页码 130-138 doi: 10.1007/s11705-013-1332-7

摘要: Magnesium hydroxide is an important chemical, and is usually obtained from seawater or brine via precipitation process. The particle size distribution of magnesium hydroxide has great effects on the subsequent filtration and drying processes. In this paper, micron-sized magnesium hydroxide with high purity, large particle size and low water content in filter cake was synthesized via simple wet precipitation in a mixed suspension mixed product removal (MSMPR) crystallizer. The effects of reactant concentration, residence time and impurities on the properties of magnesium hydroxide were investigated by X-Ray diffraction (XRD), Scanning Electron Microscopy (SEM) and Malvern laser particle size analyzer. The results show that NaOH concentration and residence time have great effects on the water content and particle size of Mg(OH) . The spherical Mg(OH) with uniform diameter of about 30 μm was obtained with purity higher than 99% and water content less than 31%. Furthermore, the crystallization kinetics based on the population balance theory was studied to provide the theoretical data for industrial enlargement, and the simulation coefficients ( ) based on ASL model and C-R model are 0.9962 and 0.9972, respectively, indicating that the crystal growth rate of magnesium hydroxide can be well simulated by the size-dependent growth models.

关键词: magnesium hydroxide     precipitation     micron-sized     crystallization kinetics    

Bimetallic Ni-Fe catalysts derived from layered double hydroxides for CO methanation from syngas

Honggui Tang, Shuangshuang Li, Dandan Gong, Yi Guan, Yuan Liu

《化学科学与工程前沿(英文)》 2017年 第11卷 第4期   页码 613-623 doi: 10.1007/s11705-017-1664-9

摘要: Carbon deposition and sintering of active components such as nano particles are great challenges for Ni-based catalysts for CO methanation to generate synthetic natural gas from syngas. Facing the challenges, bimetallic catalysts with different Fe content derived from layered double hydroxide containing Ni, Fe, Mg, Al elements were prepared by co-precipitation method. Nanoparticles of Ni-Fe alloy were supported on mixed oxides of aluminium and magnesium after calcination and reduction. The catalysts were characterized by Brunner-Emmett-Teller (BET), X-ray diffraction, hydrogen temperature programmed reduction, inductively coupled plasma, X-ray photoelectron spectroscopy, transmission electron microscopy and thermogravimetric techniques, and their catalytic activity for CO methanation was investigated. The results show that the Ni-Fe alloy catalysts exhibit better catalytic performance than monometallic catalysts except for the Ni4Fe-red catalyst. The Ni2Fe-red catalyst shows the highest CO conversion (100% at 260–350 °C), as well as the highest CH selectivity (over 95% at 280–350 °C), owing to the formation of Ni-Fe alloy. In stability test, the Ni2Fe-red catalyst exhibits great improvement in both anti-sintering and resistance to carbon formation compared with the Ni0Fe-red catalyst. The strong interaction between Ni and Fe element in alloy and surface distribution of Fe element not only inhibits the sintering of nanoparticles but restrains the formation of Ni clusters.

关键词: methanation     layered double hydroxide     bimetal Ni-Fe alloy     sintering     carbon deposition    

标题 作者 时间 类型 操作

Synthesis and characterization of magnesium hydroxide by batch reaction crystallization

Xingfu SONG, Shuying SUN, Dengke ZHANG, Jin WANG, Jianguo YU

期刊论文

Noble-metal-free cobalt hydroxide nanosheets for efficient electrocatalytic oxidation

Jie Lan, Daizong Qi, Jie Song, Peng Liu, Yi Liu, Yun-Xiang Pan

期刊论文

Hierarchically porous cellulose nanofibril aerogel decorated with polypyrrole and nickel-cobalt layered double hydroxide

期刊论文

Layered double hydroxide-based core-shell nanoarrays for efficient electrochemical water splitting

Wenfu Xie, Zhenhua Li, Mingfei Shao, Min Wei

期刊论文

Defective Nickle–Iron Layered Double Hydroxide for Enhanced Photocatalytic NO Oxidation with Significant

Xiaoyu Li,Xiaoshu Lv,Jian Pan,Peng Chen,Huihui Peng,Yan Jiang,Haifeng Gong,Guangming Jiang,Li'an Hou,

期刊论文

Crosslinking acrylamide with EDTA-intercalated layered double hydroxide for enhanced recovery of Cr(VI

Jing Li, Haiqin Yu, Xue Zhang, Rixin Zhu, Liangguo Yan

期刊论文

Utilization of aluminum hydroxide waste generated in fluoride adsorption and coagulation processes for

Jiawei JU,Ruiping LIU,Zan HE,Huijuan LIU,Xiwang ZHANG,Jiuhui QU

期刊论文

ALKALINE PRETREATMENT AND AIR MIXING FOR IMPROVEMENT OF METHANE PRODUCTION FROM ANAEROBIC CO-DIGESTION OF POULTRY LITTER WITH WHEAT STRAW

期刊论文

Chemical mapping of cement pastes by using confocal Raman spectroscopy

Fengjuan LIU,Zhihui SUN

期刊论文

Performance of bioferric-submerged membrane bioreactor for dyeing wastewater treatment

ZOU Haiyan, XI Danli

期刊论文

β-Nickel hydroxide cathode material for nano-suspension redox flow batteries

Yue LI, Cheng HE, Elena V. TIMOFEEVA, Yujia DING, Javier PARRONDO, Carlo SEGRE, Vijay RAMANI

期刊论文

碱式碳酸锌热分解机理及动力学

马正先,韩跃新,刘春生,郑龙熙,王泽红

期刊论文

Thermal defluorination behaviors of PFOS, PFOA and PFBS during regeneration of activated carbon by molten salt

期刊论文

Preparation and crystallization kinetics of micron-sized Mg(OH)

Xingfu SONG, Kefeng TONG, Shuying SUN, Ze SUN, Jianguo YU

期刊论文

Bimetallic Ni-Fe catalysts derived from layered double hydroxides for CO methanation from syngas

Honggui Tang, Shuangshuang Li, Dandan Gong, Yi Guan, Yuan Liu

期刊论文