scholarly journals Applications of Mechanochemically Prepared Layered Double Hydroxides as Adsorbents and Catalysts: A Mini-Review

Nanomaterials ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 80 ◽  
Author(s):  
Jun Qu ◽  
Lin Sha ◽  
Chenjie Wu ◽  
Qiwu Zhang
Keyword(s):  
Surface Defects ◽  
Raw Materials ◽  
High Surface ◽  
Chemical Properties ◽  
Dry Milling ◽  
Application Performance ◽  
Double Hydroxide ◽  
Double Hydroxides ◽  
Unique Chemical ◽  
Catalytic Performances

Mechanochemically prepared layered double hydroxide (M-LDH), which usually possesses high surface chemical activity and a substantial amount of surface defects, has presented outstanding application performance especially in the area of environmental protection. Recently published works on the mechanochemical synthesis of LDH were first introduced to provide a comprehensive summary on the preparation of the materials. Ensuing discussion provided an overview of recent research on the applications of M-LDH products as adsorbents and catalysts. The excellent adsorption performance and fast adsorption rate of the precursor of LDH produced by dry milling of raw materials was identified. The catalytic performances of M-LDH as catalysts, mainly photocatalysts, were then introduced. It is foreseeable that by rational utilization of mechanochemical processes and the unique chemical properties of M-LDH, increasing numbers of applications using M-LDH could be expected.

scholarly journals Layered Double Hydroxide (LDH) Based Photocatalysts: An Outstanding Strategy for Efficient Photocatalytic CO2 Conversion

Catalysts ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1185 ◽  
Author(s):  
Abdul Razzaq ◽  
Shahzad Ali ◽  
Muhammad Asif ◽  
Su-Il In
Keyword(s):  
Low Cost ◽  
High Surface ◽  
High Surface Area ◽  
Co2 Concentration ◽  
Co2 Conversion ◽  
Critical Issues ◽  
Fuels And Chemicals ◽  
Double Hydroxide ◽  
Double Hydroxides ◽  
Photocatalytic Co2 Conversion

CO2 conversion to solar fuels/chemicals is an alluring approach for narrowing critical issues of global warming, environmental pollution, and climate change, caused by excess atmospheric CO2 concentration. Amongst various CO2 conversion strategies, photocatalytic CO2 conversion (PCC) is considered as a promising approach, which utilizes inexpensive sunlight and water with a photocatalyst material. Hence, development of an efficient and a stable photocatalyst is an essential activity for the respective scientific community to upscale the PCC research domain. Until today, metal oxides, such as TiO2, ZnO, etc., are categorized as standard photocatalysts because of their relative stability, abundant availability and low cost. However, their performance is tethered by limited light absorption and somewhat physical properties. Recently, layered double hydroxides (LDHs) have offered an exciting and efficient way for PCC due to their superb CO2 adsorption and moderate photocatalytic properties. The LDH based photocatalysts show marvelous physiochemical and electrical properties like high surface area, stability, and excellent conductivity. In the present review article, a summarized survey is portrayed regarding latest development for LDH based photocatalysts with a focus on synthesis strategies employing various photocatalyst materials, influencing parameters and possible mechanism involved in PCC to useful fuels and chemicals like CO, CH4, CH3OH, and H2.

Synthesis and characterisation of aqueous miscible organic-layered double hydroxides

2014 ◽  
Vol 2 (36) ◽  
pp. 15102-15110 ◽  
Author(s):  
Chunping Chen ◽  
Miaosen Yang ◽  
Qiang Wang ◽  
Jean-Charles Buffet ◽  
Dermot O'Hare
Keyword(s):  
Surface Area ◽  
Layered Double Hydroxide ◽  
Layered Double Hydroxides ◽  
High Surface ◽  
High Surface Area ◽  
New Family ◽  
Double Hydroxide ◽  
Double Hydroxides

We report the synthesis and characterisation of a new family of high surface area and dispersible layered double hydroxides entitled Aqueous Miscible Organic Layered Double Hydroxide (AMO-LDH).

Defects in Crystals

1968 ◽  
Vol 26 ◽  
pp. 244-245
Author(s):  
Kenneth R. Lawless
Keyword(s):  
Electron Microscope ◽  
Point Defects ◽  
Surface Defects ◽  
Chemical Properties ◽  
Material Point ◽  
Crystal Defects ◽  
Defects In Crystals ◽  
Irradiation Effects ◽  
Normal Lattice ◽  
Line Defects

One of the most important applications of the electron microscope in recent years has been to the observation of defects in crystals. Replica techniques have been widely utilized for many years for the observation of surface defects, but more recently the most striking use of the electron microscope has been for the direct observation of internal defects in crystals, utilizing the transmission of electrons through thin samples.Defects in crystals may be classified basically as point defects, line defects, and planar defects, all of which play an important role in determining the physical or chemical properties of a material. Point defects are of two types, either vacancies where individual atoms are missing from lattice sites, or interstitials where an atom is situated in between normal lattice sites. The so-called point defects most commonly observed are actually aggregates of either vacancies or interstitials. Details of crystal defects of this type are considered in the special session on “Irradiation Effects in Materials” and will not be considered in detail in this session.

In Situ microscopy of the anodic etching of silicon

1995 ◽  
Vol 53 ◽  
pp. 232-233
Author(s):  
Frances M. Ross ◽  
Peter C. Searson
Keyword(s):  
Composite Structures ◽  
High Surface ◽  
High Surface Area ◽  
Chemical Properties ◽  
Selective Etching ◽  
Silicon On Insulator ◽  
Second Phase ◽  
Porous Layers ◽  
New Class ◽  
Porous Semiconductors

Porous semiconductors represent a relatively new class of materials formed by the selective etching of a single or polycrystalline substrate. Although porous silicon has received considerable attention due to its novel optical properties1, porous layers can be formed in other semiconductors such as GaAs and GaP. These materials are characterised by very high surface area and by electrical, optical and chemical properties that may differ considerably from bulk. The properties depend on the pore morphology, which can be controlled by adjusting the processing conditions and the dopant concentration. A number of novel structures can be fabricated using selective etching. For example, self-supporting membranes can be made by growing pores through a wafer, films with modulated pore structure can be fabricated by varying the applied potential during growth, composite structures can be prepared by depositing a second phase into the pores and silicon-on-insulator structures can be formed by oxidising a buried porous layer. In all these applications the ability to grow nanostructures controllably is critical.

Diesel Biofuels - Preparation, Characterization and Testing

2008 ◽  
Vol 59 (11) ◽  
Author(s):  
Cristina Dusescu ◽  
Anca Borcea ◽  
Vasile Matei ◽  
Ion Popa ◽  
Irina Gabriela Radulescu
Keyword(s):  
Vegetable Oils ◽  
Sunflower Oil ◽  
Raw Materials ◽  
Chemical Properties ◽  
Soya Bean ◽  
Production Unit ◽  
Physical And Chemical Properties ◽  
Physical And Chemical ◽  
And Chemical Properties

The present paper studies biodiesel samples preparation by transesterification and compares their physical and chemical properties (biofuels prepared from different raw materials - vegetable oils: sunflower oil, crocus oil and soya bean oil) and the biodegradability degree, as well as the possibilities of the integration of such production unit in industrial diagram of auto fuels production.

Physical - Chemical Issues of Cephalosporin Intercalated Nanoparticles for Life - Threatening Infections Treatment

2001 ◽  
Vol 71 (3) ◽  
pp. 342-349
Author(s):  
Lucian Eva ◽  
Letitia Doina Duceac ◽  
Liviu Stafie ◽  
Constantin Marcu ◽  
Geta Mitrea ◽  
...  
Keyword(s):  
Chemical Characterization ◽  
Advanced Characterization ◽  
Generation Cephalosporin ◽  
Fourth Generation ◽  
Exchange Method ◽  
Physico Chemical ◽  
Life Threatening ◽  
Double Hydroxide ◽  
Double Hydroxides

The fourth generation cephalosporin antibacterial agent, cefepime, was loaded into layered double hydroxides for enhancing antibiotic efficiency, reducing side effects, as well as achieving the sustained release property. The intercalation of antibiotic into the inter-gallery of ZnAl-layered double hydroxide (LDH) was carried out using ion exchange method, by this constituting a nano-sized organic-inorganic hybrid material for a controlled release novel formulation. Although cefepime is a broad spectrum antibiotic, it has various adverse effects and a significant degradation rate. Thus, the preparation and physico-chemical characterization of nanomaterials able to intercalate this drug is an important study for medical and pharmaceutical field. The antibiotic inclusion into LDHs nanostructure was confirmed by advanced characterization techniques and the release profile of cefepime was analysed with the respect to pH of the simulated media.

Anthocyanins: Chemical Properties and Health Benefits: A Review

2021 ◽  
Vol 17 ◽  
Author(s):  
Siraj Salman Mohammad ◽  
Renata Oliveira Santos ◽  
Maria Ivone Barbosa ◽  
José Lucena Barbosa Junior
Keyword(s):  
Raw Materials ◽  
Health Benefits ◽  
Chemical Properties ◽  
Extraction Methods ◽  
The Body ◽  
Raw Material ◽  
Extraction Properties ◽  
Therapeutic Properties ◽  
Food Processes ◽  
Shed Light

: Anthocyanins are widely spread in different kinds of food, especially fruits and floral tissues, there is an extensive range of anthocyanin compounds reach more than 600 exist in nature. Anthocyanins can be used as antioxidants and raw material for several applications in food and pharmaceutical industry. Consequently, a plenty of studies about anthocyanins sources and extraction methods were reported. Furthermore, many studies about their stability, bioactive and therapeutic properties have been done. According to the body of work, we firstly worked to shed light on anthocyanin properties including chemical, antioxidant and extraction properties. Secondly, we reported the applications and health benefits of anthocyanin including the applications in food processes and anthocyanin characteristics as therapeutic and prophylactic compounds. We reviewed anticancer, anti-diabetic, anti-fatness, oxidative Stress and lipid decreasing and vasoprotective effects of anthocyanins. In conclusion, because the importance of phytochemicals and bioactive compounds the research is still continuing to find new anthocyanins from natural sources and invest them as raw materials in the pharmaceutical and nutrition applications.

scholarly journals Polymer/Iron-Based Layered Double Hydroxides as Multifunctional Wound Dressings

Pharmaceutics ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 1130
Author(s):  
Mariana Pires Figueiredo ◽  
Ana Borrego-Sánchez ◽  
Fátima García-Villén ◽  
Dalila Miele ◽  
Silvia Rossi ◽  
...  
Keyword(s):  
Drug Release ◽  
High Performance ◽  
Mechanical Performance ◽  
Release Kinetics ◽  
Wound Dressings ◽  
In Vitro Drug Release ◽  
Improved Performance ◽  
Double Hydroxide ◽  
Double Hydroxides

This work presents the development of multifunctional therapeutic membranes based on a high-performance block copolymer scaffold formed by polyether (PE) and polyamide (PA) units (known as PEBA) and layered double hydroxide (LDH) biomaterials, with the aim to study their uses as wound dressings. Two LDH layer compositions were employed containing Mg2+ or Zn2+, Fe3+ and Al3+ cations, intercalated with chloride anions, abbreviated as Mg-Cl or Zn-Cl, or intercalated with naproxenate (NAP) anions, abbreviated as Mg-NAP or Zn-NAP. Membranes were structurally and physically characterized, and the in vitro drug release kinetics and cytotoxicity assessed. PEBA-loading NaNAP salt particles were also prepared for comparison. Intercalated NAP anions improved LDH–polymer interaction, resulting in membranes with greater mechanical performance compared to the polymer only or to the membranes containing the Cl-LDHs. Drug release (in saline solution) was sustained for at least 8 h for all samples and release kinetics could be modulated: a slower, an intermediate and a faster NAP release were observed from membranes containing Zn-NAP, NaNAP and Mg-NAP particles, respectively. In general, cell viability was higher in the presence of Mg-LDH and the membranes presented improved performance in comparison with the powdered samples. PEBA containing Mg-NAP sample stood out among all membranes in all the evaluated aspects, thus being considered a great candidate for application as multifunctional therapeutic dressings.

scholarly journals Postsynthetic treatment of nickel–iron layered double hydroxides for the optimum catalysis of the oxygen evolution reaction

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Daire Tyndall ◽  
Sonia Jaskaniec ◽  
Brian Shortall ◽  
Ahin Roy ◽  
Lee Gannon ◽  
...  
Keyword(s):  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Size Control ◽  
Operating Conditions ◽  
Nickel Iron ◽  
Treatment Techniques ◽  
Site Density ◽  
Synthetic Approaches ◽  
Double Hydroxide ◽  
Double Hydroxides

AbstractNickel–iron-layered double hydroxide (NiFe LDH) platelets with high morphological regularity and submicrometre lateral dimensions were synthesized using a homogeneous precipitation technique for highly efficient catalysis of the oxygen evolution reaction (OER). Considering edge sites are the point of activity, efforts were made to control platelet size within the synthesized dispersions. The goal is to controllably isolate and characterize size-reduced NiFe LDH particles. Synthetic approaches for size control of NiFe LDH platelets have not been transferable based on published work with other LDH materials and for that reason, we instead use postsynthetic treatment techniques to improve edge-site density. In the end, size-reduced NiFe LDH/single-wall carbon nanotube (SWCNT) composites allowed to further reduce the OER overpotential to 237 ± 7 mV (<L> = 0.16 ± 0.01 μm, 20 wt% SWCNT), which is one of the best values reported to date. This approach as well improved the long-term activity of the catalyst in operating conditions.

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