Environmental;
Science;
and;
Engineering;
Institute,;
Chang;
'an;
University,;
Xi'an,;
Shaanxi;
710054,;
China;
Xi'an;
Institute;
of;
Geology;
and;
Minerals;
Resources,;
Xi'an,;
Shaanxi;
710054,;
China;
Xi;
'an;
Institute;
of;
Thermal;
Power;
Research,;
Xi'an,;
Shaanxi;
710032,;
China;