TY - JOUR
T1 - Highly efficient and irreversible removal of cadmium through the formation of a solid solution
AU - Wang, Chen
AU - Yin, Hui
AU - Bi, Lei
AU - Su, Jing
AU - Zhang, Meiyi
AU - Lyu, Tao
AU - Cooper, Mick
AU - Pan, Gang
PY - 2020/2/15
Y1 - 2020/2/15
N2 - Sulfur-containing materials are very attractive for the efficient decontamination of some heavy metals. However, the effective and irreversible removal of Cd2+, coupled with a high uptake efficiency, remains a great challenge due to the relatively low bond dissociation energy of CdS. Herein, we propose a new strategy to overcome this challenge, by the incorporation of Cd2+ into a stable ZnxCd1-xS solid solution, rather than into CdS. This can be realised through the adsorption of Cd2+ by ZnS nanoparticles, which have exhibited a Cd2+ uptake capacity of approximate 400 mg g−1. Through this adsorption mechanism, the Cd2+ concentration in a contaminated solution could effectively be reduced from 50 ppb to <3 ppb, a WHO limit acceptable for drinking water. In addition, ZnS continued to exhibit this noteworthy uptake capacity even in the presence of Cu2+, Pb2+, and Hg2+. ZnS displayed high chemical stability. Particles aged in air for 3 months still retained a> 80% uptake capacity for Cd2+, compared with only 9% uptake capacity for similarly-aged FeS particles. This work reveals a new mechanism for Cd2+ removal with ZnS and establishes a valuable starting point for further studies into the formation of solid solutions for hazardous heavy metal removal applications.
AB - Sulfur-containing materials are very attractive for the efficient decontamination of some heavy metals. However, the effective and irreversible removal of Cd2+, coupled with a high uptake efficiency, remains a great challenge due to the relatively low bond dissociation energy of CdS. Herein, we propose a new strategy to overcome this challenge, by the incorporation of Cd2+ into a stable ZnxCd1-xS solid solution, rather than into CdS. This can be realised through the adsorption of Cd2+ by ZnS nanoparticles, which have exhibited a Cd2+ uptake capacity of approximate 400 mg g−1. Through this adsorption mechanism, the Cd2+ concentration in a contaminated solution could effectively be reduced from 50 ppb to <3 ppb, a WHO limit acceptable for drinking water. In addition, ZnS continued to exhibit this noteworthy uptake capacity even in the presence of Cu2+, Pb2+, and Hg2+. ZnS displayed high chemical stability. Particles aged in air for 3 months still retained a> 80% uptake capacity for Cd2+, compared with only 9% uptake capacity for similarly-aged FeS particles. This work reveals a new mechanism for Cd2+ removal with ZnS and establishes a valuable starting point for further studies into the formation of solid solutions for hazardous heavy metal removal applications.
U2 - 10.1016/j.jhazmat.2019.121461
DO - 10.1016/j.jhazmat.2019.121461
M3 - Journal article
SN - 0304-3894
JO - Journal of Hazardous Materials
JF - Journal of Hazardous Materials
ER -