ABSTRACT

Studies were done to investigates the effects of temperature and acid treatment on Geheku clay samples, focusing on alterations in functional groups, surface properties, and elemental composition. The Geheku clay underwent crushing, grinding, and heating to eliminate moisture. 10% (v/v) concentration of HCl stock solution was 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 slight 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, Si-O-Si bending vibration at 909.5 cm-1. Comparatively, treated clay samples at 200°C and 400°C exhibited minimal variations in these frequencies, indicating modifications induced by acid treatment and thermal activation. BET analysis showed acid treatment lead to surface area reduction and pore volume loss, heating at higher temperature partially restored these properties . For untreated clay, the surface area by BET was 285.021 m2/g, while for treated clay samples at 200°C  it decreased to 207.218 m2/g. However heating at 400°C resulted in surface area recovery  with value of 291.003 m2/g. Pore volume also reduced from 0.171 cm3/g for untreated clay to 0.119 cm3/g at 200°C, while there was a partial recovery at 400°C with pore volume at  0.143 cm3/g for treated clay samples .SEM-EDX analysis highlighted variations in elemental composition, with notable changes in silicon, iron, silicon, aluminum, and other elements post-treatment. For instance, silicon  content increased from 56.80% in untreated clay to