Preparation of hydrogen sulfide adsorbent derived from spent Fenton-like reagent modified biochar and its removal characteristics for hydrogen sulfide

Hydrogen sulfide has serious harm to human health and equipment safety. Spent Fenton-like reagent poses a challenge to the environment. In this article, a cost-effective adsorbent was prepared from rice straw biochar modified with spent Fenton-like reagent, and was used to remove gaseous hydrogen sulfide. Effects of several parameters and gas components on hydrogen sulfide adsorption, and hydrogen sulfide adsorption mechanism were studied. Results show that spent Fenton-like reagent modification promotes the rise of active sites on biochar surface, but results in the decline of adsorbent specific surface area. The optimum calcination temperature of adsorbent is 300 °C, and the maximum adsorption capacity for hydrogen sulfide is up to 1000.6 mg/g at 120 °C, which is far more than similar adsorbents. Presence of gas components such as sulfur dioxide, nitric oxide or water vapor inhibits the desulfurization performance of adsorbent to varying degrees. Copper oxide is confirmed to be the key active substance for hydrogen sulfide adsorption on adsorbent, and copper sulphide, cuprous sulfide and elemental sulfur are found to be the main products of hydrogen sulfide removal on adsorbent. The study provides new ideas for utilization of spent Fenton-like reagent and development of cost-effective hydrogen sulfide adsorbent.