The Si/Al ratios effect on Fe-aluminosilicate from red mud for sustainable green diesel production

Red mud conversion into Fe-aluminosilicate catalysts offers a route to sustainable catalyst production while providing efficient industrial waste management. Variation of Si/Al ratios (25, 50, 75) alters the mesoporosity and acidity of Fe-aluminosilicate, with the morphology varied from amorphous crystallites to well-defined mesopores. Si/Al ratios of 50 (RM-CTA.50) formed mesoporous channels with ∼2.39 nm size and a high surface area of 786 m²/g. Increasing the Si/Al ratio to 75 expanded the diameter of mesoporous channels to ∼3.94 nm, while the mesoporosity was less developed at Si/Al of 25. Catalytic pyrolysis of waste cooking oil achieved 99.25 % conversion with 59.64 % liquid yield when using RM-CTA.50, significantly improved from red mud at only 7.61 % liquid yield. The selectivity to liquid hydrocarbon products relied on Si/Al ratios, achieving 98 % green diesel yield on Si/Al = 50. This study demonstrates the successful modification of red mud to form mesopores Fe-aluminosilicate, achieving high catalytic activity for efficient and sustainable green diesel production from waste cooking oil.