Desulfurization or desulphurisation is a chemical process for the removal of sulfur from a material. This involves either the removal of sulfur from a molecule (e.g. A=S → A:) or the removal of sulfur compounds from a mixture such as oil refinery streams.^[1]

These processes are of great industrial and environmental importance as they provide the bulk of sulfur used in industry (Claus process and Contact process), sulfur-free compounds that could otherwise not be used in a great number of catalytic processes, and also reduce the release of harmful sulfur compounds into the environment, particularly sulfur dioxide (SO₂) which leads to acid rain.

Processes used for desulfurization include hydrodesulfurization, the SNOX process and the wet sulfuric acid process (WSA process).

• Shell–Paques process
• Flue-gas desulfurization
• Biodesulfurization