TY - JOUR
T1 - Mercury reduction and chemisorption on the surface of synthetic zeolite silver nanocomposites
T2 - equilibrium studies and mechanisms
AU - Tauanov, Z.
AU - Lee, J.
AU - Inglezakis, V. J.
PY - 2020/5/1
Y1 - 2020/5/1
N2 - This work presents the utilization of a coal power plants waste, namely coal fly ash for the synthesis of zeolites and zeolite silver nanocomposites for the removal of Hg2+ from water. Equilibrium data are derived for all materials for mercury concentration range of 10–500 mg/L and models are applied. The removal mechanisms are discussed in detail and complemented by XRD, XRF, SEM-EDS, and TEM characterizations and water phase mercury speciation modeling. According to findings, the adsorption capacity of zeolites is about 4 mg/g and increased by almost 5 times after the modification with silver nanoparticles to 20.5–22.3 mg/g. Langmuir equilibrium model fits well the experimental data of the nanocomposites indicating monolayer adsorption process. The mechanism is complex, involving Hg2+ reduction to Hg+ and possibly Hg0 followed by formation of calomel and amalgams on the surface of the nanocomposites. The mercury reduction is accompanied by Ag0 oxidation to Ag+ and subsequent formation of silver chloride.
AB - This work presents the utilization of a coal power plants waste, namely coal fly ash for the synthesis of zeolites and zeolite silver nanocomposites for the removal of Hg2+ from water. Equilibrium data are derived for all materials for mercury concentration range of 10–500 mg/L and models are applied. The removal mechanisms are discussed in detail and complemented by XRD, XRF, SEM-EDS, and TEM characterizations and water phase mercury speciation modeling. According to findings, the adsorption capacity of zeolites is about 4 mg/g and increased by almost 5 times after the modification with silver nanoparticles to 20.5–22.3 mg/g. Langmuir equilibrium model fits well the experimental data of the nanocomposites indicating monolayer adsorption process. The mechanism is complex, involving Hg2+ reduction to Hg+ and possibly Hg0 followed by formation of calomel and amalgams on the surface of the nanocomposites. The mercury reduction is accompanied by Ag0 oxidation to Ag+ and subsequent formation of silver chloride.
KW - adsorption isotherms
KW - mercury removal
KW - nanocomposites
KW - silver
KW - zeolites
UR - http://www.scopus.com/inward/record.url?scp=85081135180&partnerID=8YFLogxK
U2 - 10.1016/j.molliq.2020.112825
DO - 10.1016/j.molliq.2020.112825
M3 - Article
AN - SCOPUS:85081135180
SN - 0167-7322
VL - 305
JO - Journal of Molecular Liquids
JF - Journal of Molecular Liquids
M1 - 112825
ER -