ABSTRACT
This study investigates the effect of thermal activation on clay from the Geheku Clay Region in Kogi State, Nigeria, focusing on structural, textural, and chemical modifications induced by heating. Clay samples were calcined at 200°C and 400°C and subsequently characterized by Fourier Transform Infrared (FTIR) spectroscopy, X-ray Diffraction (XRD), and Brunauer– Emmett–Teller (BET) surface area analysis. FTIR spectra of the 200°C sample exhibited characteristic bands at 3690.1 cm⁻¹ (–OH stretching vibration), 1114.5 cm⁻¹ (Si–O in-plane stretching), 909.5 cm⁻¹ (Al–OH vibrations), 793.9 cm⁻¹ (Si–O stretching), and 685.8 cm⁻¹ (Si– O–Al bending). The 400°C sample showed a similar spectral profile with a slight shift, featuring a band at 3693.8 cm⁻¹ and an additional band at 1002.7 cm⁻¹, attributed to Si–O–Si asymmetric stretching, indicative of subtle structural rearrangements upon further thermal treatment. XRD analysis revealed well-defined diffraction peaks at approximately 21.11°, 24.23°, 26.88°, 27.69°, 36.83°, and 50.31° (2θ), confirming the presence of quartz, orthoclase, albite, and kaolinite as the predominant phases in the clay. BET measurements demonstrated that the specific surface area increased from 123.6 m²/g at 200°C to 136.8 m²/g at 400°C, while the pore volume decreased from 0.079 cc/g to 0.074 cc/g, and the average pore diameter slightly increased from 2.43 nm to 2.46 nm. These findings highlight that thermal activation enhances the surface reactivity and structural ordering of clay, which may improve its performance in catalytic, ceramic, and environmental remediation applications.
