HCl-Induced Hg^(0)Transformation over CuMn_(2)O_(4)Sorbent

CuMn_(2)O_(4)spinel has been regarded as a highly efficient sorbent for Hg^(0)capture from flue gas.The regenerability and recyclability of CuMn_(2)O_(4)sorbent are mainly associated with the mercury speciation adsorbed on its surface.However,the effect mechanism of HCl on Hg^(0)transformation over CuMn_(2)O_(4)sorbent is still elusive.Experiments were conducted to understand the effect of HCl on Hg^(0)transformation over CuMn_(2)O_(4)sorbent.The results indicate thatCuMn_(2)O_(4)sorbent is a mesoporousmaterial and possesses a good thermal stability.CuMn_(2)O_(4)shows>95%Hg^(0)removal efficiency in a wide temperature window of 50-350℃.The favorable electron-transfer environment caused by the mixed valence states of Cu and Mn cations is responsible for the excellent Hg^(0)removal performance of CuMn_(2)O_(4)sorbent.CuMn_(2)O_(4)shows a higherHg^(0)adsorption capacity of 4774.57μg/g.Hg^(0)adsorption process over CuMn_(2)O_(4)sorbent can bewell described by the developed kinetic model.Hg^(0)removal efficiency of CuMn_(2)O_(4)sorbent does not depend on the presence of HCl.Mercury species adsorbed on the CuMn_(2)O_(4)sorbent in the presence of HCl mainly exist in the forms of Hg^(O)and HgCl_(2)O_(8)·H_(2)O.HCl shows a significant effect on mercury speciation over CuMn_(2)O_(4)sorbent.Most of Hg^(O)species will be transformed into HgCl_(2)O_(8)·H_(2)O in the presence of HCl.