Abstract: Sulfur dioxide (SO₂), found in the flue gas of nonferrous smelting, is an irritating and toxic gas that poses significant environmental pollution risks and results in the loss of valuable sulfur resources. China, as a major consumer of sulfur, faces a substantial shortage in domestic supply, relying heavily on imports. Capturing and recovering SO₂ in an environmentally friendly and safe way is crucial for the sustainable development of the industry. Ionic liquids (ILs) hold great promise for SO₂ capture and resource recovery owing to their unique chemical structures and physical properties, high stability, good controllability and strong recyclability. They offer innovative solutions for addressing air pollution and resource recycling and are expected to have widespread industrial applications, contributing significantly to environmental protection and sustainable resource utilization. Current research on ionic liquid desulfurization mainly focuses on the synthesis of new ionic liquids, their performance in SO₂ removal, and recyclability, with less emphasis on the recycling of captured SO₂. This study explores the SO₂ absorption and conversion efficiency of the tetramethylguanidine acetate (TMGAc) system by coupling the Claus reaction mediated by the ionic liquid absorber. Experimental results indicate that TMGAc, prepared by acid-base neutralization, exhibits excellent SO₂ absorption capacity with a saturation adsorption capacity of 1.06 g at 20 ℃ and a SO₂ flow rate of 50 mL·min⁻¹, outperforming other absorbers with the same cation. By adding H₂S gas, the trapped SO₂ can be rapidly converted into sulfur at room temperature, achieving up to 99% conversion. The products from the Claus reaction were heated to sulfur’s melting point, causing the sulfur to liquefy and aggregate, allowing it to separate from the absorbent. The sulfur products were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray energy dispersive spectroscopy (EDS). These results indicated that the prepared sulfur product was S₈, demonstrating that the TMGAc ionic liquid, based on the Claus reaction, successfully produced sulfur. After four cycles, the TMGAc absorbent maintained a consistent SO₂ conversion rate, absorbent mass, and SO₂ absorption capacity, indicating its stability and effectiveness. The absorbent exhibited excellent thermal stability and regenerability during the cycling process, indicating its capacity to be regenerated through the Claus reaction and reused as a recyclable absorbent for SO₂ capture. Using infrared spectroscopy (IR) and nuclear magnetic resonance spectroscopy (NMR) characterization methods, the mechanism of SO₂ absorption by TMGAc was studied. The results indicate that the interaction among the amino groups on the cation of the absorbent and the hydrogen bonds on the anion is crucial for SO₂ capture. Finally, the transformation mechanism of SO₂ absorption was explored in aqueous and nonaqueous systems. This study not only provides the foundations for efficient ionic liquid desulfurization of ionic liquids but also explores the potential for SO₂ recycling, supporting sustainable and high-quality development in the nonferrous smelting industry.