Reduction of sulphur dioxide emission into the environment by adsorption on enhanced α-hematite surface

The top priority of the sustainable development goals is to improve the quality of the environment for better living. Sulphur dioxide is considered more hazardous than any other gases that pollute the environment and harm the well-being of organisms. In 2019, India alone accounted for 21% of the world's SO₂ emissions. Strict action is required to reduce maximum levels of SO₂ emission to the atmosphere to improve the total air quality. To reduce SO₂ emissions more effectively, in this study, α-hematite was chemically activated by using 5% NaOH and C₂H₅OH with the help of a double bed adsorption column. The adsorbent properties of α-hematite were studied by Brunauer-Emmett-Teller isotherm, which revealed a high surface area (539 m² g^-1), and pore size (2.3125 nm) and high volume in the pore (0.0293432 cm³ mg^-1). FTIR confirmed that the SO₂ particulate on the surface of the adsorbent with an adsorption capacity of 95%. The operating temperature of 40-50 °C was optimal for the chemical adsorption. It was found that the inlet concentration (64 mg m^-3) of SO₂ decreases as the adsorption of SO₂ increases. Trace SO₂ was well-adsorbed by the adsorbent, which resulted in a mass transfer zone. Freundlich's adsorption spectrum was more fit for low concentrated SO₂ than Langmuir isotherm. The results indicate that the environmental emission of SO₂ can be reduced with chemically enhanced α-hematite.