scholarly journals Special Issue “Sustainable Remediation Processes Based on Zeolites”

Processes ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 2153
Author(s):  
Claudia Belviso
Keyword(s):  
General Formula ◽  
Divalent Cations ◽  
Three Dimensional ◽  
Special Issue ◽  
Sustainable Remediation ◽  
Dimensional Network

Zeolites are microporous tectosilicates characterized by a three-dimensional network of tetrahedral (Si, Al)O4 units with the general formula: Mx+Ly2+[Al(x+2y)Si1−(x+2y)O2n]·mH2O where M+ and L2+ are monovalent and divalent cations [...]

Li9Yb2[PS4]5 and Li6Yb3[PS4]5: two lithium-containing ytterbium(III) thiophosphates(V) revisited

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Pia L. Lange ◽  
Thomas Schleid
Keyword(s):  
Single Crystals ◽  
General Formula ◽  
Elemental Sulfur ◽  
Elevated Temperatures ◽  
Three Dimensional ◽  
Structure Type ◽  
Framework Structure ◽  
Red Phosphorus ◽  
Space Group ◽  
Dimensional Network

Abstract The lithium ytterbium ortho-thiophosphates Li9Yb2[PS4]5 and Li6Yb3[PS4]5 were prepared through the reaction of stoichiometric amounts of ytterbium metal, elemental sulfur, red phosphorus and lithium hemisulfide at elevated temperatures in sealed silica tubes. The compounds occur as dark red single crystals which crystallize monoclinically in space group C2/c with the lattice parameters a = 1487.98(9), b = 978.63(6), c = 2046.75(12) pm and β = 96.142(3)° for Li9Yb2[PS4]5 (Z = 4) and a = 2814.83(16), b = 997.34(6), c = 3338.52(19) pm and β = 113.685(3)° for Li6Yb3[PS4]5 (Z = 12). Li9Yb2[PS4]5 can be assigned to the structure type of Li9Nd2[PS4]5, whereas the structure of Li6Yb3[PS4]5 the structure is similar to that of the prototypic Li6Gd3[PS4]5. Both structures feature discrete [PS4]3– tetrahedra (d(P–S) = 202–207 pm) and strands of [YbS8]13− polyhedra (d(Yb–S) = 271–319 pm) propagating along [010]. When attributed to the general formula (Li3[PS4]) x (Yb[PS4]) y , ideas of the dimensionality of both structures can be derived. Whilst the lithium-richer Li9Yb2[PS4]5 (x/y = 1.5) develops planes with the composition   ∞ 2 { [ Y b [ P S 4 ] 3 ] 6 − } ${}_{\infty }^{2}\left\{{\left[\mathrm{Y}\mathrm{b}{\left[\mathrm{P}{\mathrm{S}}_{4}\right]}_{3}\right]}^{6-}\right\}$ , Li6Yb3[PS4]5 (x/y = 0.667) exhibits a rather complex three-dimensional network of ytterbium-centered polyhedra connected via [PS4]3– tetrahedra with lithium cations in the framework structure   ∞ 3 { [ Y b 3 [ P S 4 ] 5 ] 6 − } ${}_{\infty }^{3}\left\{{\left[\mathrm{Y}{\mathrm{b}}_{\mathrm{3}}{\left[\mathrm{P}{\mathrm{S}}_{4}\right]}_{5}\right]}^{6-}\right\}$ . These Li+ cations are hard to locate in both compounds, but reside in four- to sixfold sulfur coordination (d(Li–S) = 235–304 pm). Some Li+ positions are underoccupied and some Li+ cations share sites with Yb3+ cations in Li6Yb3[PS4]5, and even in Li9Yb2[PS4]5 their high displacement values suggest Li+ cation mobility. According to the empirical formulae, three Li+ cations have to be replaced with one Yb3+ cation to reach the lithium-poorer compound and structure (Li6Yb3[PS4]5) starting from the lithium-richer one (Li9Yb2[PS4]5).

scholarly journals Special Issue: Nanocomposite Hydrogels for Biomedical Applications

2020 ◽  
Vol 10 (1) ◽  
pp. 389 ◽  
Author(s):  
Kazuaki Matsumura
Keyword(s):  
Biomedical Applications ◽  
Three Dimensional ◽  
Polymer Chains ◽  
Special Issue ◽  
Nanocomposite Hydrogels ◽  
Dimensional Network

A hydrogel consists of a three-dimensional network of polymer chains, with water as a solvent in the system [...]

Development of Mucoadhesive Buccal Drug Delivery System of Propranolol Hydrochloride Using Aster ericoides Mucilage

2020 ◽  
Vol 10 (2) ◽  
pp. 133-148
Author(s):  
Ankaj Kaundal ◽  
Pravin Kumar ◽  
Rajendra Awasthi ◽  
Giriraj T. Kulkarni
Keyword(s):  
Buccal Cavity ◽  
Three Dimensional ◽  
Hot Water ◽  
Fickian Diffusion ◽  
Aster Ericoides ◽  
Dimensional Network ◽  
Buccal Tablet ◽  
Significant Difference ◽  
Volunteer Group

Aim: The study was aimed to develop mucoadhesive buccal tablets using Aster ericoides leaves mucilage. Background : Mucilages are naturally occurring high-molecular-weight polyuronides, which have been extensively studied for their application in different pharmaceutical dosage forms. Objective: The objective of the present research was to establish the mucilage isolated from the leaves of Aster ericoides as an excipient for the formulation of the mucoadhesive buccal tablet. Method: The mucilage was isolated from the leaves of Aster ericoides by maceration, precipitated with acetone and characterized. Tablets were prepared using wet granulation technique and evaluated for various official tests. Results: The mucilage was found to be non-toxic on A-431 and Vero cell lines. It was insoluble but swellable in cold and hot water. The results indicate that mucilage can form a three-dimensional network. The pH of the mucilage (6.82 ± 0.13) indicated that it might be non-irritant to the buccal cavity. The mucilage was found to be free from microbes. The release of drug was by Fickian diffusion. The in vivo buccal tablet acceptance was 80%. No significant difference between the diastolic blood pressure of standard and Aster tablets treated volunteer group was recorded. Conclusion: The mucilage was found to be non-toxic on A-431 and Vero cell lines. It was insoluble but swellable in cold and hot water. The results indicate that mucilage can form a three-dimensional network. The pH of the mucilage (6.82 ± 0.13) indicated that it might be non-irritant to the buccal cavity. The mucilage was found to be free from microbes. The release of drug was by Fickian diffusion. The in vivo buccal tablet acceptance was 80%. No significant difference between the diastolic blood pressure of standard and Aster tablets treated volunteer group was recorded. Other: However, to prove the potency of the polymer, in vivo bioavailability studies in human volunteers are needed along with chronic toxicity studies in suitable animal models.

scholarly journals Crystal structure of K[Hg(SCN)3] – a redetermination

2014 ◽  
Vol 70 (9) ◽  
pp. i46-i46 ◽  
Author(s):  
Matthias Weil ◽  
Thomas Häusler
Keyword(s):  
Crystal Structure ◽  
Room Temperature ◽  
Three Dimensional ◽  
Lattice Parameters ◽  
Bond Lengths ◽  
Dimensional Network ◽  
Anisotropic Displacement Parameters ◽  
Precision And Accuracy ◽  
Standard Deviations ◽  
Atomic Coordinates

The crystal structure of the room-temperature modification of K[Hg(SCN)3], potassium trithiocyanatomercurate(II), was redetermined based on modern CCD data. In comparison with the previous report [Zhdanov & Sanadze (1952).Zh. Fiz. Khim.26, 469–478], reliability factors, standard deviations of lattice parameters and atomic coordinates, as well as anisotropic displacement parameters, were revealed for all atoms. The higher precision and accuracy of the model is, for example, reflected by the Hg—S bond lengths of 2.3954 (11), 2.4481 (8) and 2.7653 (6) Å in comparison with values of 2.24, 2.43 and 2.77 Å. All atoms in the crystal structure are located on mirror planes. The Hg2+cation is surrounded by four S atoms in a seesaw shape [S—Hg—S angles range from 94.65 (2) to 154.06 (3)°]. The HgS4polyhedra share a common S atom, building up chains extending parallel to [010]. All S atoms of the resulting1∞[HgS2/1S2/2] chains are also part of SCN−anions that link these chains with the K+cations into a three-dimensional network. The K—N bond lengths of the distorted KN7polyhedra lie between 2.926 (2) and 3.051 (3) Å.

scholarly journals An investigation of polyhedral deformation in two mixed-metal diarsenates: SrZnAs2O7and BaCuAs2O7

2015 ◽  
Vol 71 (4) ◽  
pp. 330-337 ◽  
Author(s):  
Sabina Kovač ◽  
Ljiljana Karanović ◽  
Tamara Đorđević
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
General Formula ◽  
Three Dimensional ◽  
X Ray Diffraction ◽  
Hydrothermal Conditions ◽  
X Ray ◽  
Open Framework ◽  
Geometrical Characteristics ◽  
Barium Copper

Two isostructural diarsenates, SrZnAs2O7(strontium zinc diarsenate), (I), and BaCuAs2O7[barium copper(II) diarsenate], (II), have been synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction. The three-dimensional open-framework crystal structure consists of corner-sharingM2O5(M2 = Zn or Cu) square pyramids and diarsenate (As2O7) groups. Each As2O7group shares its five corners with five differentM2O5square pyramids. The resulting framework delimits two types of tunnels aligned parallel to the [010] and [100] directions where the large divalent nine-coordinatedM1 (M1 = Sr or Ba) cations are located. The geometrical characteristics of theM1O9,M2O5and As2O7groups of known isostructural diarsenates, adopting the general formulaM1IIM2IIAs2O7(M1II= Sr, Ba, Pb;M2II= Mg, Co, Cu, Zn) and crystallizing in the space groupP21/n, are presented and discussed.

scholarly journals Construction of the Cellulose Nanofibers (CNFs) Aerogel Loading TiO2 NPs and Its Application in Disposal of Organic Pollutants

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1841
Author(s):  
Kang Li ◽  
Xuejie Zhang ◽  
Yan Qin ◽  
Ying Li
Keyword(s):  
High Efficiency ◽  
Sol Gel ◽  
Cellulose Nanofibers ◽  
Three Dimensional ◽  
Good Mechanical Property ◽  
Polar Groups ◽  
Dimensional Network ◽  
Natural Polysaccharide ◽  
Valuable Method ◽  
Adsorption Capability

Aerogels have been widely used in the adsorption of pollutants because of their large specific surface area. As an environmentally friendly natural polysaccharide, cellulose is a good candidate for the preparation of aerogels due to its wide sources and abundant polar groups. In this paper, an approach to construct cellulose nanofibers aerogels with both the good mechanical property and the high pollutants adsorption capability through chemical crosslinking was explored. On this basis, TiO2 nanoparticles were loaded on the aerogel through the sol-gel method followed by the hydrothermal method, thereby the enriched pollutants in the aerogel could be degraded synchronously. The chemical cross-linker not only helps build the three-dimensional network structure of aerogels, but also provides loading sites for TiO2. The degradation efficiency of pollutants by the TiO2@CNF Aerogel can reach more than 90% after 4 h, and the efficiency is still more than 70% after five cycles. The prepared TiO2@CNF Aerogels have high potential in the field of environmental management, because of the high efficiency of treating organic pollutes and the sustainability of the materials. The work also provides a choice for the functional utilization of cellulose, offering a valuable method to utilize the large amount of cellulose in nature.

scholarly journals Enhanced bacterial disinfection by CuI–BiOI/rGO hydrogel under visible light irradiation

RSC Advances ◽  
2021 ◽  
Vol 11 (33) ◽  
pp. 20446-20456
Author(s):  
Xi Ma ◽  
Ziwei Wang ◽  
Haoguo Yang ◽  
Yiqiu Zhang ◽  
Zizhong Zhang ◽  
...  
Keyword(s):  
Electron Transport ◽  
Visible Light ◽  
Network Structure ◽  
Visible Light Irradiation ◽  
Three Dimensional ◽  
Light Irradiation ◽  
Transport Capacity ◽  
Highly Efficient ◽  
Dimensional Network ◽  
Bacterial Disinfection

Compared with traditional layered graphene, graphene hydrogels have been used to construct highly efficient visible light-excited photocatalysts due to their particular three-dimensional network structure and efficient electron transport capacity.

scholarly journals Investigations of polyethylene of raised temperature resistance service performance using autoclave test under sour medium conditions

e-Polymers ◽  
2021 ◽  
Vol 21 (1) ◽  
pp. 346-354
Author(s):  
Guoquan Qi ◽  
Hongxia Yan ◽  
Dongtao Qi ◽  
Houbu Li ◽  
Lushi Kong ◽  
...  
Keyword(s):  
Oil And Gas ◽  
Mechanical Performance ◽  
Three Dimensional ◽  
Service Performance ◽  
Degree Of Branching ◽  
Temperature Resistance ◽  
Temperature Conditions ◽  
Dimensional Network ◽  
Gas Medium ◽  
Better Than

Abstract The chapter deals with the performance evaluation of the polyethylene of raised temperature resistance (PE-RT) and polyethylene (PE) using autoclave test under sour oil and gas medium conditions. The analyses of performance changes showed that PE-RT has good media resistance at 60°C. As the temperature increases, its mechanical properties decrease, accompanied by an increase in weight. Comparative analyses showed that no matter what temperature conditions are, PE-RT media resistance is better than PE80. The better media resistance of PE-RT depends on its higher degree of branching. Short branches are distributed between the crystals to form a connection between the crystals, thereby improving its heat resistance and stress under high-temperature conditions. PE-RT forms an excellent three-dimensional network structure through copolymerization, ensuring that it has better media resistance than PE80. However, the mechanical performance will be attenuated due to the high service temperature.

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