Natural clay mineral-periwinkle activated carbon composite: Characterisation and structural insight

Abstract

The intricacies of a natural clay mineral-periwinkle shell activated carbon (NM-PAC) composite were examined using
Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), BET surface area analysis, and Fourier
Transform Infrared spectroscopy (FTIR). TEM analysis revealed irregular shaped particles with sizes of around 100 nm and relatively good distribution characteristics. Further examination with SEM supported these findings, showing a heterogeneous microstructure with activated carbon particles evenly distributed within the clay matrix. This uniform distribution was indicative of a high surface area available for adsorption. BET surface area analysis of the NM-PAC was determined to be 72.243 m²/g. FTIR analysis highlighted the presence of characteristic absorption bands related to the
vibrational and rotational states of various functional groups. The broad band in the range of 3700–3000 cm^-1
indicated the stretching vibration of hydroxyl groups, and new bands around 1730 cm^-1 , 1250 cm^-1, and 1040 cm^-1, suggested the presence of carbonyl, carboxyl, and phenol groups respectively. These findings provide valuable insights into the composite's structural properties and its potential for improved adsorption efficiency, particularly for the removal of polar pollutants.