TAGRA 2024

Clay minerals are hydrous silicate sheets with a layered structure of the phyllosilicate type, which are composed of oxygen (O) and hydroxide (OH) layers. Generally, they are product of chemical weathering of other silicate minerals on the Earth's surface, and are considered to be among the most abundant substances in nature. In mineralogy, particles smaller than 4 microns (0.004 mm) are referred to as clays, regardless of their chemical composition. The placement of oxygen (O) and hydroxide (OH) layers creates spaces where cations can settle. Clays have many applications in various industries. The properties and applications of clays depend on their internal structure and composition. The surface activities of clays depend on the chemical composition, the nature of the surface atoms (Mainly oxygen and hydrogen), the type and number of adsorption sites, the surface charge, and the type of exchangeable cations. Large surface area, high cation exchange capacity, mechanical and chemical stability, sheet structure, abundance, and easy modification are effective factors for selecting clays as a cleaning agent in environmental applications. The most important environmental applications of clay minerals include controlling waste landfills, absorbing pollutants, reducing the use of pesticides and fertilizers, etc. One of the important characteristics of clay minerals in relation to their application in the environment is their absorption capacity, which is increased by various methods such as acid, alkali, surfactant and salt treatments and is used as a cheap and effective adsorbent in removing environmental pollutants. The environmental applications of clays are growing and developing, and their modification by various methods improves their efficiency, but it should be borne in mind that excessive exploitation of clay resources will cause environmental effects such as land degradation, destruction of wildlife habitats, soil pollution, air pollution, and water pollution. Therefore, one must be cautious and use these resources properly. The unplanned, uncontrolled use and recovery of clay minerals can cause many problems for the environment.