The scrubbing of hydrogen sulfide (H2S) using sodium hydroxide (NaOH) solution is established technology, and has been applied in a variety of industries. The removal of small amounts of H2S from gas streams is typically referred to as scavenging. Caustic is often classified as an H2S scavenger, and competes with other scavengers such as solid reactive adsorbents. https://drizgas.com/h2s-scrubber.php