Industrial Applications of Clay Materials from Ghana (A Review)
Total Page：16
File Type：pdf, Size：1020Kb
ORIENTAL JOURNAL OF CHEMISTRY ISSN: 0970-020 X CODEN: OJCHEG An International Open Free Access, Peer Reviewed Research Journal 2018, Vol. 34, No.(4): Pg. 1719-1734 www.orientjchem.org Industrial Applications of Clay Materials from Ghana (A Review) R. B. Asamoah1, E. NyanKSON1, E. ANNAN1, B. AGYEI-TUFFOUR1, J. K. EfaVI1, K. KAN-DAPAAH2, V. A. APalangya3, L. N. W. Damoah1, D. DODOO-ARHIN1, E. K. Tiburu2, S. K. Kwofie2, B. Onwona-AGYEMAN and A.Yaya1,4* 1Department of Materials Science & Engineering, CBAS, University of Ghana, Legon, Ghana. 2Department of Biomedical Engineering, CBAS, University of Ghana, Legon, Ghana. 3Department of Food Process Engineering, CBAS, University of Ghana, Legon, Ghana. 4Institut des Matériaux Jean Rouxel (IMN), UMR 6502, CNRS, Université de Nantes, France. *Corresponding author E-mail: [email protected] http://dx.doi.org/10.13005/ojc/340403 (Received: June 29, 2018; Accepted: July 30, 2018) Abstract Clay minerals are phyllosilicate groups naturally found in soils in all parts of the world. They have proven to be among the most essential industrial minerals because of their unique physicochemical properties and versatile applications within a wide range of fields including ceramics, construction, and environmental remediation, biomedical as well as cosmetics. Clay minerals are also primary to the production of other materials such as composite for secondary applications. In Ghana, clay mineral deposits are commonly found in several areas including soil horizons as well as geothermal fields and volcanic deposits, and are formed under certain geological conditions. This review seeks to explore the geographical occurrence and discusses the current uses of various local clay materials in Ghana in order to highlight opportunities for the utilization of these materials for other applications. Keywords: Clay minerals, Ceramics, Properties, Application, Ghana. Introduction uses such as geophagy to contemporary use in pottery, construction and water purification. Clay Though clay deposits are ubiquitous in is overly distributed and each deposit has unique Ghana and have important domestic applications, properties that can be tailored towards a particular their physicochemical properties for such application application. The clay deposits in the regions are has not been fully explored.1 The importance of given in Fig. 1. According to Kesse (1985), clays are clay is demonstrated mainly in various applications mainly of either alluvial or residual sources and are that are documented as well as those classified as formed from rock dissolution and sedimentation.3 traditional uses without prior scientific knowledge.2 The deposits may be found covered by a few meters In Ghana, the use of clay extend from traditional thickness of superficial soil such as humus. The This is an Open Access article licensed under a Creative Commons Attribution-Non Commercial-Share Alike 4.0 International License (https://creativecommons.org/licenses/by-nc-sa/4.0/), which permits unrestricted Non Commercial use, distribution and reproduction in any medium, provided the original work is properly cited. Yaya et al., Orient. J. Chem., Vol. 34(4), 1719-1734 (2018) 1720 various deposits of clay shown in Fig. 1, consist of applications continue to improve through synthesis different kinds of clay minerals as studied by the of other materials such as zeolites and clay mineral- Ghana Geological Survey Department-Ceramics polymer nano-composites using clay as template.15 Laboratory (1999). According to the study, clay In Ghana, clay mineral deposits are densely deposits possesses properties relating to weight dispersed across the entire land area. Every region shrinkage, moisture content, plasticity and raw in Ghana has a measure of clay deposits.16 The colour.4 Structurally, they are natural layered material local clays differ by colour and other properties primarily occurring in soils with relatively smaller such as cohesion, viscosity and fired strength. particle size components.5 The chemical structures The geographical location for each clay materials of clay minerals are dominated by arrays of planar confer unique physico-chemical properties which SiO4 and Al2O3 structural hydroxyls and water. Also, ultimately determines the type of material produced different materials such as feldspar, mica and quartz, and its application.17 This paper reviews local clays are mostly produced from weathered rocks and other in Ghana and their diverse applications. The current volcanic activities. These rocks are formed under review provides the characteristic of clay minerals high temperatures and pressure beneath the earth deposits in the country to relate their usefulness surface.6 The dissolution of primary rock minerals for the ceramics, environmental remediation and release ions which crystalize in aqueous environment healthcare disciplines. for the formation of these clays. Even though clay are mostly associated with soil, the components of clay Synthesis Methods; Using Clay as Template is generally porous and normally filled with water and The properties of clay minerals are also 19 air compared to ordinary soil which is amorphous in subject to change through modification. The nature and disaggregated.7 Other contaminants may structure and composition of clay minerals can be also complicate the formation of clay and this may altered to obtain diverse functionalities. Kaolinite result in the non-homogeneous nature of the mineral consist of alternating octahedral and silicate tetrahedral structures. The tetrahedral sheets (SiO ) particles. An important adage of the association of 4 and octahedral sheets (AlO (OH) ) are bonded by clay with soil is that mineral particles can diffuse 2 4 20 into the pore structures of the clay materials Van der Waals forces and hydrogen bonding. 21 hence making it plastic and introduces different Cheng (1998) , modified the structure of kaolin properties and application for the material.8 They by the introduction of potassium acetate in the interlayer spacing of kaolin clay mineral. Potassium also have varying water content and this enables acetate breaks the interconnecting Van der Waals their swelling ability which results in their plasticity forces and allows the formation of hydrogen characteristics.9,10 The properties of clay also allows bonding between adjacent layers. The interlayer molding and shaping leading to cohesiveness in spacing of kaolin then increases from about 7.8 Å 11 the material. The properties of clay materials may to about 14.70 Å.21 Grafting reactions of covalent be further impacted by modifying their structure bonds can sequentially take place between the through processes such as composite formulations. hydroxyl of octahedral and organic molecules Modified clays consequently result in a charge and (Al-O-C) which consequently alters the properties surface properties suitable for nanocomposites, of clay mineral such as thermal, chemical, surface organoclays, acid and induced clays synthesis.12,13 area, etc.22 The modified clay has characteristics Clay-polymer composites have also altered chemical which is significantly different from the unmodified constituents and structure of nanoclays for various counterpart. For instances, properties such as clay applications. The applications of modified clay just porosity may be altered. The change in clay porosity as natural clay are greatly achieved by knowledge influences its use in applications such as adsorption of the modification procedure and its associated of organic compounds.23 Ion exchange is a preferred properties.14 medium for modifying clay with organic molecules. Cations are not strongly bonded to clay minerals The applications of clays are numerous hence small molecule cations can replace them. spanning across disciplines such as geology, Surfactants containing short hydroxyl groups, benzyl, construction, environmental remediation, aliphatic chains and long ones are used to increase pharmaceutical and cosmetics industries. These basal spacing between layers.24 The ion exchange, Yaya et al., Orient. J. Chem., Vol. 34(4), 1719-1734 (2018) 1721 changes surface properties of clay minerals which Thermally and mechanically induced clay is another can act as adsorbents. Intercalation of clay by form of modified clay. Local clay minerals in Ghana organic molecules has led to well defined materials have been modified through a number of processes of extreme structural and chemical performance such as hydrothermal synthesis15 and composite for example in clay-polymer nanocomposite. preparations5,12,13,14 to create other materials such as Clay minerals can also be modified through zeolites, electroporcelain insulators, etc. Additionally, acid-induced and salt-induced methods which are modified clays can have applications in medicine, good adsorbents in catalysis for degrading oil. energy and environment. Fig. 1. A map of the Clay mineral deposits in Ghana. Source: Geological Survey Department, Ghana, showing the clay deposits spread across the entire land area. The country has 238,535km2 land size with significant amount of clay reserves in commercial quantities18 Clay Minerals distribution in Ghana clays in Ghana are mainly of either alluvial or residual The clay minerals in Ghana are deposited sources. Clays are formed from rock dissolution and across all the regions in many areas of the entire sedimentation and may cover few meters from the land mass, Table 1. According to the findings, the superficial soil; normally humus.27 Yaya et al., Orient.