Deposition of sulfur from H2S on porous adsorbents and effect on their mercury adsorption capacity

✍ Scribed by Sandra Vitolo; Roberto Pini

• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 171 KB
• Volume: 28
• Category: Article
• ISSN: 0375-6505
• DOI: 10.1016/s0375-6505(99)00012-7

✦ Synopsis

The deposition of elemental sulfur on porous adsorbents (commercial pre-sulfurised activated carbons and alumina, an HY zeolite and a selenised adsorbent) has been observed when the adsorbents are exposed to a gaseous stream containing hydrogen sul®de and oxygen. The sulfur deposition from H 2 S is more marked for the activated carbons and the alumina, it is substantially decreased when zeolite is used, and is practically insigni®cant for the selenium-based adsorbent. For the pre-sulfurised activated carbons, further sulfur deposition is initially bene®cial in terms of increasing their mercury chemisorbing capacity but, subsequently, the structural properties are aected and this results in a drastic reduction in adsorption capacity. Further sulfur deposition on the pre-sulfurised alumina seems immediately to compromise its capacity to chemisorb mercury. The selenium-based adsorbent shows problems with detachment of the ®ne mercuric selenide powder from the matrix. Sulfur deposition on the initially unsulfurised zeolite improves its mercury adsorption capability. The initially sulfur-free zeolite could be a promising adsorbent for the treatment of this speci®c type of gas stream. In fact, after a moderate level of sulfur deposition from oxidation of hydrogen sul®de, it can simultaneously chemisorb the mercury vapours by reaction with the sulfur itself while, unlike the activated carbons and alumina,