Continuous Oxidation of Hydrogen Sulfide by an Adsorbent Derived from Sewage Sludge

Abstract

Desulfurization (deS) material is usually deactivated because elemental sulfur formed during deS and covers the material surface. In this study, a novel strategy was proposed for a continuous oxidization of hydrogen sulfide (H2S) by a sewage sludge-derived adsorbent without elemental-sulfur deposition. At temperatures <180°C, the sludge-derived adsorbent was deactivated and showed limited deS amount of 0.27 mmol/g at 60 min. Scanning Electron Microscope (SEM) and Fourier Transform infrared spectroscopy showed that carbon sites of the deactivated adsorbent were covered by elemental sulfurs. After the deactivated adsorbent was regenerated at 200°C, it showed a deS amount of 0.25 mmol/g again. On the contrary, at temperatures >180°C, the adsorbent achieved a stable deS without deactivation, resulting in a deS amount of 121.82 mmol/g at 20 h. In this case, yellow particles evolved from the adsorbent. X-ray diffraction and Thermogravimetric Analysis both proved that the particles were sulfur. Sulfur outflow was a key factor determining the regeneration of active carbon sites and continuous oxidization of H2S. This study will help the development of a low-cost adsorbent for H2S purification.