Abstract
The study investigates the structural, thermal, and adsorption properties of natural diatomite and its modified forms (thermally and acid-treated) for oil spill remediation. X-ray diffraction analysis revealed amorphous silica alongside crystalline phases. Thermogravimetric analysis showed mass losses at 80–300 °C (removal of adsorbed water) and 430–700 °C (dehydroxylation), with an 8.63% total mass loss. Acid treatment with 0.5N H2SO4 significantly altered the chemical composition, increasing the SiO2 content to 88.8% while dissolving CaO, Na2O, and MnO2. Infrared spectroscopy confirmed the removal of hydroxyl groups and structural changes following treatment. Nitrogen adsorption analysis revealed enhanced porosity in the acid-modified diatomite (D-H2SO4-400), showing a BET surface area of 80.0 m2/g and a uniform pore size distribution of 19.0 nm. Scanning electron microscopy revealed preserved skeletal structures with improved porosity. Oil sorption tests showed that D-H2SO4-400 exhibited the highest adsorption capacity (optimal at 4 g, 30 µm particle size), achieving maximum uptake within 2 minutes. Overall, these findings confirm that thermal and acid treatments enhance the sorption efficiency of diatomite, making it a promising low-cost and environmentally friendly material for oil spill remediation.