Effects of clay minerals in soil pollution
Subject Areas : Journal of Food Safety and Processing
1 - Assistant Professor, Department of Agro-Ecology, Faculty of Agriculture, Islamic Azad University, VaraminPishva and Qarchak branch
Keywords: Soil Pollution, Clay Minerals, surface adsorption,
Abstract :
In addition to providing nutrients, soil also has a purifying property. This characteristic of the soil is obtained as a result of the physical (infiltration and movement of water through the pores), chemical (surface absorption, etc.) and biological properties of the soil (decomposition and decay of organic matter). Clay minerals are cation exchangers and have an important effect on the storage capacity and mobility of heavy metals in the soil. There is a positive relationship between cation exchange capacity and heavy metal absorption. Kaolinite mineral does not show a significant correlation with the amount of heavy metals and forms the weakest cation-clay bond. Studies have shown that there are no polluting elements with this mineral. Minerals of the smectite group are strong cation exchangers and their presence can affect the mobility of toxic elements. Studies confirm the positive correlation between the presence of vermiculite and heavy metals, which is probably due to the higher specific levels and bonding capacity of this type of mineral. Minerals that have variable electric charge, such as iron and aluminum oxides, which have various charges from positive to negative depending on soil pH, have a large storage capacity. Surface absorption and release of heavy metals in soils is significantly controlled by the amount and proportion of secondary oxide minerals. Therefore, phyllosilicate and oxide clay minerals are effective as a surface absorbing agent for the correction and treatment of potential environmental pollution, and the capacity of trapping and surface absorption of heavy metals by them can be an important parameter for evaluating the geochemical vulnerability of an ecosystem.
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