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The soil ecosystem
Published in Stephen R. Gliessman, V. Ernesto Méndez, Victor M. Izzo, Eric W. Engles, Andrew Gerlicz, Agroecology, 2023
Stephen R. Gliessman, V. Ernesto Méndez, Victor M. Izzo, Eric W. Engles, Andrew Gerlicz
Once minerals are released from the consolidated parent material, another chemical process that is of great importance is the formation of secondary minerals, the most important being clay minerals. Clay minerals are very small particles in the soil, but they affect everything from water retention to nutrient availability. They are formed by complex processes in which silicate minerals are chemically modified and reorganized. Depending on the combination of climatic conditions and parent material, the secondary minerals that are formed are of two basic types. Silicate clays are predominantly made up of microscopic aluminum silicate “plates” with different arrangements; hydroxide clays lack a definite crystalline structure and are made up of hydrated iron and aluminum oxides in which many of the silicon ions have been replaced.
Petroleum Geological Survey
Published in Muhammad Abdul Quddus, Petroleum Science and Technology, 2021
Silicates are polymeric compounds composed of individual metal oxides linked together through various covalent and coordinate bonds, forming enormous numbers of silicate minerals. The oxides are the basic units (monomers) of the macromolecule silicates. The chemical formulae of silicates are complex, but can be simplified to ‘metal oxide – aluminum oxide – silicon oxide’. These oxides are naturally arranged in different ways to produce a variety of stable neutral molecules forming different groups. Crystal and chemical structures of silicates are discussed in Chapter 8. On the basis of their similarity in mineralogy, the total silicates in magma may be conveniently placed into seven mineral groups. Brief descriptions of each silicate mineral group are given below.
Polymer Silica Nanocomposite Gel Electrolytes for Lithium-Ion Batteries
Published in Prasanth Raghavan, Fatima M. J. Jabeen, Polymer Electrolytes for Energy Storage Devices, 2021
Akhila Das, Anjumole P. Thomas, Neethu T. M. Balakrishnan, Nikhil Medhavi, Jou-Hyeon Ahn, Fatima M. J. Jabeen, Prasanth Raghavan
Silica ( SiO2 ) is one the most abundant, low-cost and eco-friendly ceramic materials present in the Earth’s crust. In silica, each silicon atom is surrounded by four oxygen atoms in a tetrahedral arrangement. The bond angle formed between O-Si-O is approximately 109°28′. Silica is a colorless solid with a molecular mass of 60.08 g mol−1. Silica is thermally stable up to 1700°C. Considering the polymer electrolytes employed as electrolytes for LIBs, the crystallinity of silica is the highest. For Li+-ion conduction in LIBs, the polymeric membrane should have both crystalline and amorphous phase. The crystalline domains in the polymer provides mechanical strength to the electrolyte, whereas the amorphous phase provides the medium for Li+-ion conduction, which increases the ionic conductivity, as well as the Li+-ion transference number. On incorporation of silica, these ceramic fillers penetrate the polymeric matrix, destroying the crystallinity of the polymer, inducing more amorphous regions, as shown in Figure 10.3. Silica is a unique material, with inertness, thermal stability, etc. It also facilitates the conductivity of the membrane by forming a networked structure.
Studying some networks using topological descriptors and multi-criterion decision making
Published in Molecular Physics, 2023
Guoping Zhang, Arfa Mushtaq, Adnan Aslam, Saima Parveen, Salma Kanwal
Choosing a leading network is our main perspective. We have four networks These networks are of the same class and . tetrahedron is the fundamental unit of these networks. Essentially, every silicate contains tetrahedron where the corner and the centre vertices represent oxygen and silicon ions, respectively. has a network structure of tetrahedron which is at the centre and is at each vertex. So this chemical compound has many physical properties which include density, melting point, boiling point, entropy and thermal conductivity, etc. In order to choose the leading network with respect to topological indices as criteria, the decision matrix is
Green production of silica nanoparticles from maize stalk
Published in Particulate Science and Technology, 2020
Jeleel Adekunle Adebisi, Johnson Olumuyiwa Agunsoye, Sefiu Adekunle Bello, Muthiah Haris, Mercy Munyadziwa Ramakokovhu, Michael Olawale Daramola, Suleiman Bolaji Hassan
Silicon production from synthetic materials such as silicon halides through thermal decomposition has been found in the literature (Zulehner et al. 1977). However, impurities from hot filament have been reported as one of the challenges. Also, silicon synthesis from chemical reduction of silica by using carbonaceous materials such as coke, wood, and coal chips have unfortunately released carbon (IV) oxide to atmosphere, increasing the risk of air pollution (Forny et al. 2007; Pijarn et al. 2010; Chattoraj, Shi, and Sun 2011; Vella et al. 2011; Konwar and De 2014). Literature has shown that MS contains substantial amounts of silica with other compounds, which can be used as a source for silicon production (Adebisi et al. 2017b). Besides, silica itself is used in pharmaceutical/medicinal, food processing, and alloy making industries (Joshi et al. 2008; Joiner 2009; Yuvakkumar et al. 2014b).
Sedimentary copper mineralization in the upper red formation, Yakhab area, central Iran
Published in Geosystem Engineering, 2019
Kaveh Pazand, Ali Behzadinasab, Mohammad Reza Ghaderi, Mohammad Reza Rezvanianzadeh
Representative major element analyses from eight samples of sandstone units in the URF are given in Table 1. The samples exhibit a range in SiO2 content from approximately 59% to 69% that exhibited low SiO2 and are immature. The sources of silica are quartz, feldspar and clay minerals. The amount of Al2O3 and K2O in these sandstones may be related to the presence of plagioclase. TiO2 content is in connection with rothile and opaque minerals. In the petrographic image of a sandstone thin section, dolomite as cement are seen indicate that MgO content may be associated with the presence of this mineral. High level of CaO linked with the presence of calcite cement and carbonate rock fragments.