Cu-Zn oxides nanoparticles supported on SBA-15 zeolite as a novel adsorbent for simultaneous removal of H2S and Hg0 in natural gas

Inspired by the fact that H2S can easily decompose on some metal oxides to form sulfur species and the resulting products are usually used as Hg-0 removal active sites, a novel Cu-Zn mixed oxide supported SBA-15 zeolite was controllably synthesized for simultaneous removal of Hg-0 and H2S. The Cu-Zn nanoparticles with a particle size range of 4.4-5.0 nm were successfully confined and uniformly dispersed in the two-dimensional mesopores of SBA-15. The obtained 1Cu1Zn/SBA-15 adsorbent presented an outstanding H2S and Hg-0 removal efficiencies at 30 degrees C and 30,000 h(-1), and the H2S and Hg-0 capture capacities reached to 296.78 mg.g(-1) and 12.75 mg.g(-1) at a 10% breakthrough. In addition, the spent adsorbent could be regenerated in a 5% O-2 and 95% N-2 atmosphere at 600 degrees C without obvious degradation of adsorption capacities over five cycles. We considered that the doping effects of Cu-Zn oxides were beneficial for its excellent H2S and Hg-0 removal performance at low temperatures, and the nano-confinement effect of SBA-15 was conducive to prevent the oxides nanoparticles from agglomeration in the regeneration process, thus achieving the outstanding regeneration performance. Furthermore, the polysulfide polymer formed by chemisorption of H2S on the Cu-Zn oxides surface was confirmed to be the Hg-0 active sites, which could react with gaseous mercury to form HgS. This work provided an effective way for simultaneous removal of H2S and Hg-0 in natural gas by confining nano-sized active metal oxides into the mesopores of zeolites.

Automated summary

By synthesizing a novel Cu-Zn mixed oxide supported SBA-15 zeolite, simultaneous removal of Hg-0 and H2S was achieved. The adsorbent exhibited outstanding removal efficiency and capture capacity at low temperatures and high flow rates. Moreover, the regeneration performance was excellent, providing an effective approach for simultaneous removal of H2S and Hg-0 in natural gas.