محمد سپهريان

The rapid growth of industries reliant on fossil fuels, particularly in power generation an‎d steel production sectors, has led to a significant increase in annual SO2 emissions, posing serious environmental an‎d health challenges. Despite the effectiveness of conventional desulfurization methods, limitations such as high energy consumption, waste generation, an‎d lack of sustainability have directed research interest towards the use of stable an‎d cost-effective solid nanocatalysts. In this context, the present dissertation aims to introduce a green, economical, an‎d circular economy-based approach by, for the first time, extracting alumina from coal gangue (CG) to synthesize mesoporous materials an‎d active catalysts. The findings revealed that coal gangue, due to its substantial alumina an‎d silica content, serves as a valuable source for synthesizing high-purity mesoporous materials. Mesoporous γ-Al2O3 an‎d SiO2 were produced without organic templates under optimized conditions including 6 M HCl solution, a solid-to-liquid ratio of 1:15, 150 minutes, an‎d 90 °C, achieving purities of 98.81% an‎d 99.08%, an‎d surface areas of 340.15 an‎d 392.85 m2/g, respectively. Their favorable structural characteristics, such as suitable pore volume an‎d size, confirm broad applicability in adsorption, catalysis, pharmaceutical, an‎d food industries. Furthermore, the developed process enabled approximately 80% waste recovery, contributing to the reduction of environmental impacts associated with coal gangue accumulation. Subsequently, the extracted γ-Al2O3 was utilized for the first time as a support in synthesizing SO2 removal catalysts, with iron loaded as the active component. Rare earth elements lanthanum an‎d cerium were employed as structural an‎d electronic promoters to enhance iron dispersion an‎d create oxygen vacancies. The resulting catalysts exhibited excellent SO2 conversion performance; under optimal conditions (380 °C, GHSV 6000 h⁻¹, an‎d CO/SO2 ratio of 2), SO2 conversion efficiency ranged from 98.92 ± 1.3% to 99.62 ± 0.6%, with selec‎tivity between 98.74 ± 1.4% an‎d 99.43 ± 0.7%. A 50-hour stability test confirmed sustained performance an‎d resistance to deactivation. This dissertation demonstrates that combining mesoporous materials derived from industrial waste with stable catalysts offers an efficient, cost-effective, an‎d environmentally friendly strategy for removing gaseous pollutants, especially SO2. Beyond adding value, this approach supports circular economy principles an‎d sustainable development, laying a foundation for employing these materials in similar catalytic processes such as NOx reduction.

آلودگي هوا , گوگرد دي اكسيد , كاهش كاتاليزوري , باطله زغال سنگ , La-Fe/γ-Al2O3 , Ce-Fe/γ-Al2O3

Air Pollution , sulfur dioxide , catalytic reduction , coal gangue , La-Fe/γ-Al2O3 , Ce-Fe/γ-Al2O3

Mohammad Sepehrian

Prof. Mansoor Anbia