China
Africa
Explore chapters and articles related to this topic
Biocompatible Reagents-based Green Synthesis
Published in Piyal Mondal, Mihir Kumar Purkait, Green Synthesized Iron-based Nanomaterials, 2023
Piyal Mondal, Mihir Kumar Purkait
Clay is fine particles of withered rocks, mainly consisting of phyllosilicate minerals, organic matter, and variable amounts of water trapped in the mineral structure. Clay is intensively used in making pottery, bricks and tiles. It has been suggested that clay can be utilized as supporting material for nanoparticle synthesis. Kalantari et al. (2014) used montmorillonite (MMT) as a rigid support for the synthesis of magnetite Fe3O4 nanoparticles. The Fe3O4 NP formation occurred in the interlayer space or on the surface of MMT, as confirmed with the help of TEM images. The saturation magnetization was found to increase from 12 to 32.4 emu/g for the MMT/Fe3O4 composite with Fe3O4 content increasing from 1 to 12 wt%. In another study, Ding et al. (2016) used a type of nanoclay smectite known as LAPONITE® to prepare LAPONITE®-Fe3O4 nanoparticle (LAP-Fe3O4-NPs) via coprecipitation method for in vivo magnetic resonance imaging of tumors. The LAP-Fe3O4-NPs is reported to have excellent colloidal stability (Figure 2.7).
Soils, rocks, and groundwater
Published in Rodrigo Salgado, The Engineering of Foundations, Slopes and Retaining Structures, 2022
Clays are soils made up of small particles usually constituted of clay minerals. Different soil classification systems may define the size below which particles are considered to be of clay size differently. An upper limit of 5 μm is most common. Clay minerals form most commonly from the chemical weathering of other minerals, mainly feldspars, micas, and ferromagnesian minerals. Clay minerals are quite resistant to any further weathering; accordingly, they are, for practical purposes, the end products of the weathering of different rock minerals. Clay minerals exist in the form of very small particles that typically contain a net negative charge and behave plastically when mixed with water (Mitchell and Soga (2005)) (Figure 3.14).
Petroleum Geological Survey
Published in Muhammad Abdul Quddus, Petroleum Science and Technology, 2021
Clay minerals are secondary silicates. Clay minerals are formed from other silicates, by the action of air, water and carbonic acid. Clay silicate minerals undergo hydrolysis, in the presence of water, to produce aluminum hydroxide and silicic acid. Both aluminum hydroxide and silicic acid are reactive and produce other types of silicates. Most of the clays are hydrated minerals. The grain size of clay is very small (<0.004 mm). Clay can form gels and colloidal solutions. There are many forms of clay minerals, depending on the chemical formula and their structure. Important clay minerals that make up the sediments are kaolinite, chlorite, illite and montmorillonite. All these clay minerals are soft, white with slight tinge and with layered structures. Mud is a mixture of clays and other silt-sized minerals, namely quartz and calcite.Shale minerals are formed from the compaction of mud. The shale mineral is fissile, soft and laminated clay.Mudstone is hard. Mudstone and shale are the tertiary products of clay; they are stable in atmospheric conditions.
Effect of salinity on rheological and strength properties of cement-stabilized clay minerals
Published in Marine Georesources & Geotechnology, 2020
Jie Yin, Ming-ming Hu, Gui-zhong Xu, Wen-xia Han, Yong-hong Miao
It should be noted that clay is a fine-grained soil that combines one or more clay minerals, which formed over long times from the gradual chemical weathering of rocks. Clays may show considerably different engineering behavior mainly depending on their mineralogical and chemical compositions. Pore fluid chemistry may significantly alter the chemical compositions of clays by means of exchangeable cations, which govern the engineering properties of clays in most cases (Spagnoli et al. 2010, 2011; Spagnoli, Stanjek, and Sridharan 2017; Spagnoli et al. 2018). There are three main groups of clay minerals: montmorillonite, illite and kaolinite. However, limited studies have been conducted addressing the effect of salinity on the physical properties and strength behavior of cement-stabilized clay minerals. Existing research mainly focused on the effects of inorganic salt solutions on Atterberg limits of clayey soils such as kaolinite and montmorillonite clays. It was reported that there was a slight increase in the liquid limit (LL) of kaolinite clay when exposed to strong salt solutions (Ören and Kaya 2003). In contrast, the LL of montmorillonite clay dramatically decreased when exposed to salt solutions (Rao, Sridharan, and Chandrakaran 1993; Di Maio 1996; Gleason, Daniel, and Eykholt 1997).
In vitro antibacterial activities of selected TB drugs in the presence of clay minerals against multidrug-resistant strain of Mycobacterium smegmatis
Published in Cogent Engineering, 2020
Patrick K. Arthur, Vincent Amarh, Ethel J. S. Blessie, Rebecca Yeboah, Benjamin W. Kankpeyeng, Samuel N. Nkumbaan, Elvis K Tiburu
Clay minerals have been used since pre-historic times for medical intervention including treatments of skin infections, diarrhoea and wound healing (Moosavi, 2017; Otto et al., 2016; Pavlinakova et al., 2018; Shi et al., 2018). There are different types of clay spread across the continents and they are inexpensive and environmentally friendly. The surface chemistry of clay minerals as well as their layered architecture can influence cell adhesion and growth phenotypes, and as such, there has been attempts to study the mechanism underlying the antibacterial activity of clay-based materials (Haydel et al., 2008; Morrison et al., 2016; Williams et al., 2011; Zarate-Reyes et al., 2018). The increased interest in the antibacterial activity of clay materials or its composite with other biopolymers might eventually lead to development of novel drug delivery biomaterials. It is therefore useful to understand the effect of these biomaterials on cellular growth, differentiation, virulence expression and antibiotic susceptibility in microbial pathogens.
Surface modification of low-cost bentonite adsorbents—A review
Published in Particulate Science and Technology, 2019
Jock Asanja Alexander, Muhammad Abbas Ahmad Zaini, Abdulsalam Surajudeen, El-Nafaty Usman Aliyu, Aroke Umar Omeiza
Clay is an abundant raw material with exceptional properties leading to various industrial applications that largely depend on its mineral structure and dispersions, rheological properties and composition, the presence of organic materials and impurities, type and amount of exchangeable ions and soluble salts, and textural properties. Clays and clay minerals such as montmorillonite, vermiculite, illite, kaolinite, and bentonite are widely used in process and petroleum industries, engineering and constructions, environmental remediation, ceramics and refractories, pharmaceuticals and agricultural sectors. Clays are used in advanced chemical processing because of their reactivity and catalytic activity (Vieira et al. 2010). Clays are also utilized in pharmaceuticals and food processing industries (Murray 2007).