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layered double hydroxide

Tomohito Kameda, Jumpei Oba, Toshiaki Yoshioka
Mg-Al layered double hydroxide intercalated with NO3(-) and Mg-Al oxide were found to remove hazardous materials such as B and As, as well as Cl(-) and SO4(2-), from artificial and real hot spring wastewater. However, compared with the mixture of Al2(SO4)3 and Ca(OH)2, both adsorbents were inferior for the removal of B from real hot spring wastewater. Both adsorbents were also found to remove F(-) and PO4(3-) from artificial semiconductor plant wastewater. Both adsorbents have the same ability to remove B from landfill wastewater as the mixture of Al2(SO4)3 and Ca(OH)2; furthermore, both remove Cl(-), Br(-), and SO4(2-)...
December 5, 2016: Journal of Environmental Management
Marko Pavlovic, Paul Rouster, Istvan Szilagyi
Layered double hydroxide (LDH) nanoparticles were prepared and used as solid support for superoxide dismutase (SOD) enzymes. Structural features were studied by XRD, spectroscopic methods (IR, UV-Vis and fluorescence) and TEM, while colloidal stability of the obtained materials was investigated by electrophoresis and light scattering in aqueous dispersions. The SOD quantitatively adsorbed on the LDH by electrostatic and hydrophobic interactions and kept its structural integrity upon immobilization. The composite material showed moderate resistance against salt-induced aggregation in dispersions, therefore, heparin polyelectrolyte was used to improve the colloidal stability of the system...
December 7, 2016: Nanoscale
Lei Zhou, Mingfei Shao, Cong Zhang, Jingwen Zhao, Shan He, Deming Rao, Min Wei, David G Evans, Xue Duan
A hierarchical CoNi-sulfide nanosheet array is fabricated via an in situ reduction of CoNi-layered double hydroxide (LDH) nanosheets, then a vulcanization process. The material inherits the morphology of the LDH precursor, consisting of well-distributed CoNi-alloy@CoNi-sulfide nanoparticles with a core-shell structure, and demonstrates promising performance toward hydrazine electrooxidation.
December 5, 2016: Advanced Materials
Jordan G Hamilton, Richard E Farrell, Ning Chen, Joel Reid, Renfei Feng, Derek Peak
Anthropogenic activities at the HudBay Minerals, Inc., Flin Flon (Manitoba, Canada) mining and processing facility have severely affected the surrounding boreal forest ecosystem. Soil contamination occurred via a combination of metal and sulfuric acid deposition and has resulted in forest dieback and ineffective natural recovery. A community-led effort to revegetate areas of the landscape through the application of a dolomitic limestone has been met with varied success. Zinc (Zn) speciation has shown to be closely linked to the presence or absence of an invasive metal-tolerant grass species, with soils being broadly classed into two revegetation response groups...
November 2016: Journal of Environmental Quality
Yanqi Xu, Weimin Xuan, Mengmeng Zhang, Haralampos N Miras, Yu-Fei Song
Deep desulfurization is a challenging task and global efforts are focused on the development of new approaches for the reduction of sulfur-containing compounds in fuel oils. In this work, we have proposed a new design strategy for the development of deep desulfurization heterogeneous catalysts. Based on the adopted design strategy, a novel composite material of polyoxometalate (POM)-based ionic liquid-grafted layered double hydroxides (LDHs) was synthesized by an exfoliation/grafting/assembly process. The structural properties of the as-prepared catalyst were characterized using FT-IR, XRD, TG, NMR, XPS, BET, SEM and HRTEM...
November 29, 2016: Dalton Transactions: An International Journal of Inorganic Chemistry
Cheng-Cheng Li, Yu-Jun Wang, Huan Du, Peng Cai, Willie J G M Peijnenburg, Dong-Mei Zhou
Extracellular polymeric substances (EPS) isolated from bacteria, are abound of functional groups which can react with metals and consequently influence the immobilization of metals. In this study, we combined with Zn K-edge Extended X-ray Absorption Fine Structure (EXAFS), Fourier Transform Infrared (FTIR) spectroscopy, and High-Resolution Transmission Electron Microscopy (HRTEM) techniques to study the effects of EPS isolated from Bacillus subtilis and Pseudomonas putida on Zn sorption on γ-alumina. The results revealed that Zn sorption on aluminum oxide was pH-dependent and significantly influenced by bacterial EPS...
January 2017: Environmental Pollution
Fengkai Yang, Kirill Sliozberg, Ilya Sinev, Hendrik Antoni, Alexander Bähr, Kevin Ollegott, Wei Xia, Justus Masa, Wolfgang Grünert, Beatriz Roldan Cuenya, Wolfgang Schuhmann, Martin Muhler
Co-based layered double hydroxides (LDH) catalysts with Fe and Al contents in the range from 15 to 45 at% were synthesized by an efficient co-precipitation method. In these catalysts, Fe3+ or Al3+ ions play an essential role as trivalent species to stabilize the LDH structure. The obtained catalysts were characterized by a comprehensive combination of surface- and bulk-sensitive techniques and evaluated for the oxygen evolution reaction (OER) on rotating disk electrodes. The OER activity decreased with increasing Al content for the Co- and Al-based LDH catalysts, whereas a synergistic effect in Co- and Fe-based LDHs was observed resulting in an optimal Fe content of 35 at%...
November 18, 2016: ChemSusChem
Eloisa Ríos, Magali Hernández, Ilich A Ibarra, Ariel Guzmán, Enrique Lima
Samples of layered double hydroxides were prepared by a sol-gel procedure. Quinolinate Al(C9H6NO)3 units were added during the synthesis, leading to composite quinolinate hydrotalcite-like compounds. The amount of quinolinate was varied, showing that the number of organic building blocks determines the physicochemical properties of materials, which differ significantly from those commonly reported for hydrotalcites without any quinolinate. The order of layers, specific surface area and coordination of aluminium were the parameters most significantly influenced by the presence of the quinolinate as a part of the brucite-like layers...
2016: Chemistry Central Journal
Netsirin Gissawong, Sira Sansuk, Supalax Srijaranai
A simple, rapid, in situ, and green extraction combined with a microcomplexation has been developed for the spectrophotometric determination of phosphate in water samples. Through their formation, layered double hydroxides (LDHs) were employed as the extraction medium, instantly commenced by a rapid addition of a mixed solution of Mg(2+) and Al(3+) ions into alkaline phosphate solution. After the extraction, LDH precipitate containing phosphate was dissolved by sulfuric acid and the released phosphate was subsequently detected via its complexation with molybdate in the presence of antimonyl and ascorbic acid...
November 3, 2016: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Guangbo Chen, Yufei Zhao, Lu Shang, Geoffrey I N Waterhouse, Xiaofeng Kang, Li-Zhu Wu, Chen-Ho Tung, Tierui Zhang
Monovalent Zn(+) (3d(10)4s(1)) systems possess a special electronic structure that can be exploited in heterogeneous catalysis and photocatalysis, though it remains challenge to synthesize Zn(+)-containing materials. By careful design, Zn(+)-related species can be synthesized in zeolite and layered double hydroxide systems, which in turn exhibit excellent catalytic potential in methane, CO and CO2 activation. Furthermore, by utilizing advanced characterization tools, including electron spin resonance, X-ray absorption fine structure and density functional theory calculations, the formation mechanism of the Zn(+) species and their structure-performance relationships can be understood...
July 2016: Advanced Science (Weinheim, Baden-Wurttemberg, Germany)
Svetlana Cherepanova, Natalya Leont'eva, Vladimir Drozdov, Vladimir Doronin
Simulation of X-ray diffraction patterns on the basis of the models of one-dimensional disordered crystals was used to investigate the structure of the dehydrated phase produced by dehydration of Mg-Al and Ni-Al layered double hydroxides at a temperature of ∼473-498 K. It was found that the removal of water molecules transforms the initial structure, which is a mixture of 3R1 and 2H1 polytypes, into a structure that comprises preferentially fragments of 3R2 and 1H polytypes and has some turbostratic disorder...
November 1, 2016: Acta Crystallographica. Section A, Foundations and Advances
Supreeth Nagendran, Ganga Periyasamy, P Vishnu Kamath
Imbibition of LiNO3 into gibbsite results in the formation of a single phase layered double hydroxide of the composition LiAl2(OH)6(NO3)·1.2H2O. This phase undergoes reversible dehydration along with the compression of the basal spacing accompanied by the reorientation of the nitrate in the interlayer gallery. The hydrated phase is a solid solution of two lattices: (i) a hexagonal lattice defining the ordering of atoms within the metal hydroxide layer, and (ii) a lattice of orthorhombic symmetry defining the ordering of atoms within the interlayer...
November 2, 2016: Dalton Transactions: An International Journal of Inorganic Chemistry
Jingfang Yu, Jingjing Liu, Abraham Clearfield, Johnathan E Sims, Michael T Speiegle, Steven L Suib, Luyi Sun
Layered double hydroxide (LDH) single-layer nanosheets were synthesized through a single-step process in the presence of formamide. This one-step process is simple, fast, and efficient and thus is potentially viable for large-scale production. Two key factors for the growth of LDH single-layer nanosheets, formamide concentration and LDH layer charge, were investigated thoroughly. A higher formamide concentration and a higher LDH layer charge are favorable for the growth of LDH single-layer nanosheets. The LDH single-layer nanosheets obtained at the premium formamide concentration and LDH layer charge were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and atomic force micrscopy (AFM)...
November 1, 2016: Inorganic Chemistry
Yidong Zou, Xiangxue Wang, Zhongshan Chen, Wen Yao, Yuejie Ai, Yunhai Liu, Tasawar Hayat, Ahmed Alsaedi, Njud S Alharbi, Xiangke Wang
With the development and application of graphene oxides (GO), the potential toxicity and environmental behavior of GO has become one of the most forefront environmental problems. Herein, a novel nanoscale layered double hydroxides (glycerinum-modified nanocrystallined Mg/Al layered double hydroxides, LDH-Gl), layered double oxides (calcined LDH-Gl, LDO-Gl) and metallic oxide (TiO2) were synthesized and applied as superior coagulants for the efficient removal of GO from aqueous solutions. Coagulation of GO as a function of coagulant contents, pH, ionic strength, GO contents, temperature and co-existing ions were studied and compared, and the results showed that the maximum coagulation capacities of GO were LDO-Gl (448...
October 26, 2016: Environmental Pollution
Chi Ma, Fenghua Wang, Chang Zhang, Zhigang Yu, Jingjing Wei, Zhongzhu Yang, Yongqiu Li, Zihao Li, Mengying Zhu, Liuqing Shen, Guangming Zeng
The new nanophotocatalyst MgZnCr-TiO2 was prepared by co-precipitation under different molar ratio of metals (Zn:Cr) and the loaded amount of TiO2. And it was characterized by X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy et al. Langmuir model fitted well the adsorption isotherm with the value of R(2) 0.9765, the maximum adsorption capacity was 526.32 mg g(-1), the adsorption followed pseudo second order kinetic by MgZnCr-TiO2 (1:1:2-0.05). The photocatalytic oxidation of Congo red was used to determine the photocatalytic performance of MgZnCr-TiO2 (1:1:2-0...
October 21, 2016: Chemosphere
M Li, F Liu, X B Zhang, J P Cheng
A variety of carbon materials varying from 0D to 2D, i.e. 0D nanoparticles, 1D carbon nanotubes (CNTs) and 2D reduced graphene oxide (rGO) are selected to in situ combine with Ni-Mn layered double hydroxide (LDH) to prepare electrode materials for supercapacitors. Through a simple solution method, hierarchical Ni-Mn LDH/carbon composites can be easily fabricated. A comparative study is carried out on the sandwich-like LDH/rGO, flower-like LDH/carbon black, turbostratic-structured LDH/CNTs and ternary LDH/CNTs/rGO for their structure, morphology, porous properties and electrochemical performances...
October 24, 2016: Physical Chemistry Chemical Physics: PCCP
Shirin Babaee, Ali Daneshfar, Tahere Khezeli
Magnetically separable layered double hydroxide Ni/CuAl-LDH nanocomposites were synthesized and employed as ultrasonic-assisted dispersive micro-solid phase extraction (UA-D-μSPE) sorbent to extract several carboxylic acids (namely propionic, butyric, pentanoic, hexanoic, heptanoic, octanoic, and decanoic) from non-alcoholic beer samples. Ni/CuAl-LDH sorbent was characterized by Fourier transform-infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), and vibrating sample magnetometry (VSM). Effective variables such as amount of sorbent (mg), pH and ionic strength of sample solution, volume of eluent solvent (μL), vortex, and ultrasonic times (min) were investigated via fractional factorial design (FFD)...
January 2017: Ultrasonics Sonochemistry
Mohamed Amine Djebbi, Alae Elabed, Zaineb Bouaziz, Moulay Sadiki, Soumya Elabed, Philippe Namour, Nicole Jaffrezic-Renault, Abdesslem Ben Haj Amara
Layered double hydroxide (LDH) has attracted major interest as one of the most versatile drug delivery systems especially for adsorption capacity and/or controlled delivery property of bioactive agents owing to their combining features of biohybrid. ZnAl synthesized layered double hydroxide can offer a platform to immobilize various types of bioactive compounds, particularly berberine chloride (BBC). However, the immobilization reaction of berberine chloride into ZnAl-LDH was performed by direct co-precipitation method at different ratios of BBC/LDH...
October 19, 2016: International Journal of Pharmaceutics
Yanshan Gao, Yu Zhang, Gareth R Williams, Dermot O'Hare, Qiang Wang
Aqueous miscible organic layered double hydroxides (AMO-LDHs) can act as organophilic inorganic flame retardant nanofillers for unmodified non-polar polymers. In this contribution, AMO [Mg3Al(OH)8](CO3)0.5·yH2O LDH-oxidized carbon nanotube (AMO-LDH-OCNT) hybrids are shown to perform better than the equivalent pure AMO-LDH. A synergistic effect between the AMO-LDH and OCNT was observed; this endows the hybrid material with enhanced flame retardancy, thermal stability, and mechanical properties. The thermal stability of polypropylene (PP) was significantly enhanced by adding AMO-LDH-OCNT hybrids...
October 18, 2016: Scientific Reports
Zahed Shami, Seyed Mojtaba Amininasab, Pegah Shakeri
A straightforward approach was successfully developed to fabricate a well-designed three-dimensional rough sheetlike MgAl-layered double hydroxide (LDH) array to stand vertically on poly(acrylonitrile) porous nanofibrous membranes based on an electrospun-nanofiber-templated in situ hydrothermal strategy, and then the surface was modified with cyclohexanecarboxylic acid. The as-spun highly dense ordered sheetlike LDH porous nanofabric exhibited a superior durability in superhydrophobicity and superoleophilicity, which has achieved high oil-removing capability including both oil harvesting and oil separation to harvest/separate a wide range of organic solvents and oils from an oil-water mixture and, especially, exhibited a very good recycling and reusing performance...
October 17, 2016: ACS Applied Materials & Interfaces
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