ABSTRACT
This study investigates the effects of acid treatment and thermal activation on arseni clay samples, focusing on alterations in functional groups, surface properties, and elemental composition. The arseni clay underwent crushing, grinding, and heating to eliminate moisture. Various concentrations of HCl stock solutions were prepared and used for acid treatment, followed by filtration and washing. The treated clay samples were then dried and heated to 200°C and 400°C. Characterization was performed using Fourier Transform Infrared (FTIR) spectroscopy, Brunauer-Emmet-Teller (BET) surface area analysis, and Scanning Electron Microscopy-Energy Dispersive X-ray (SEM-EDX) analysis. FTIR analysis revealed changes in functional groups, with some persisting while others decomposed or underwent alterations post-treatment. For untreated clay, characteristic absorption frequencies included OH stretching vibration at 3693.8 cm-1, N=C=S stretching vibration at 2027.7 cm-1, and Si-O stretching in-plane vibration at 1114.5 cm-1. In contrast, treated clay samples at 200°C and 400°C exhibited variations in these frequencies, indicating modifications induced by acid treatment and thermal activation. BET analysis showed significant increases in surface area, pore volume, and pore diameter after treatment. For untreated clay, the surface area by BET was 171.130 m2/g, while for treated clay samples at 200°C and 400°C, it increased to 214.149 m2/g and 227.701 m2/g, respectively. Pore volume also increased from 0.083 cm3/g for untreated clay to 0.137 cm3/g and 0.145 cm3/g for treated clay samples at 200°C and 400°C, respectively. SEM-EDX analysis highlighted variations in elemental composition, with notable changes in chlorine, magnesium, silicon, aluminum, and other elements post-treatment. For example, chlorine content increased from 0.85% in untreated clay to 0.95% in treated clay samples at 400°C, indicating its incorporation into the clay structure. The study concludes that acid treatment and thermal activation induce modifications in the clay's functional groups, surface properties, and elemental composition, with potential implications for various industrial applications.
