Modification trials towards increasing the adsorption capacity of kaolinite clay

In water treatment, clay minerals are one of the most important materials. The removal of hazardous substances from the water environment through the adsorption of clay minerals is a highly important process. Kaolinite, used as an adsorbent, enables the exchange of metal cations in wastewater contaminated with heavy metals with cations between the layers of clay, contributing to the purification of wastewater. In recent times, due to its high efficiency, ease of use, and the advantage of adsorbent recovery, the use of kaolinite for the removal of water pollutants from water has become widespread. Modification, by increasing pore size and active surface area, enhances the adsorption properties of the clay surface through this process. Considering the economic and environmental approaches of these modifications, they hold a significant place in today's world. Various applications have been found from the past to the present, and ongoing studies in this field exist. In this study, experiments were conducted on the surface modification of natural clay minerals to increase the adsorption capacity of kaolinite clay. Modified clays were obtained through saturation of raw kaolinite clay with magnesium chloride (K-MgCl.6H2O), calcination at 500°C (K-500), and saturation with sulfuric acid (H2SO4) (K-H2SO4). Changes in the surface pores and the components of the modified clays were observed and mapped using XRD and SEM imaging techniques, in comparison to the raw kaolinite clay. The greatest increase in surface pores was achieved with the K-MgCl.6H2O modification. The K-500 and K-H2SO4 modifications also resulted in an increased active surface area. SEM-EDX analysis revealed that the modified clay content primarily consisted of Aluminum (Al), Silicon (Si), Oxygen (O2), Magnesium (Mg), Manganese (Mn), Chromium (Cr), Calcium (Ca), and Sulfur (S) elements. Additionally, a high quantity of Gold (Au) was detected due to the gold coating process during analysis, which allowed for imaging.