All reagents
and solvents used
in the experiments were commercially available and used without further
purification (Innochem, China). The FT-IR absorption spectra for Cd-CP,
Hg@Cd-CP and Pb@Cd-CP were collected from KBr pellets using a Thermo
Scientific FTIR-Nicolet iS10 spectrometer in the range of 4000–400
cm–1 (Thermo Scientific, U.S.A.). Powder X-ray diffraction
(PXRD) was performed in the 2θ range of 5–50° on
a Rigaku X-ray diffractometer with Cu Kα radiation (λ
= 1.5418 Å) (Rigaku, Japan). Elemental analyses were carried
out on a PerkinElmer 2400C elemental analyzer (Elementar, Germany).
TGA data were acquired using a Mettler-Toledo simultaneous thermal
analyzer from room temperature to 800 °C under an N2 atmosphere at a heating rate of 10 °C min–1 (Netzsch, Germany). XPS was performed using a K-Alpha X-ray photoelectron
spectrometer (Thermo Scientific, USA). The morphology and energy-dispersive
spectroscopy (EDS) data of Cd-CP, Hg@Cd-CP, and Pb@Cd-CP were obtained
using a Nova NanoSEM 450 field-emission scanning electron microscope
(SEM) at 10 Kv (Thermo Scientific, U.S.A.). The concentration of metal
ions was determined with an iCAP6300 ICP-AES (Thermo Scientific, U.S.A.).
and solvents used
in the experiments were commercially available and used without further
purification (Innochem, China). The FT-IR absorption spectra for Cd-CP,
Hg@Cd-CP and Pb@Cd-CP were collected from KBr pellets using a Thermo
Scientific FTIR-Nicolet iS10 spectrometer in the range of 4000–400
cm–1 (Thermo Scientific, U.S.A.). Powder X-ray diffraction
(PXRD) was performed in the 2θ range of 5–50° on
a Rigaku X-ray diffractometer with Cu Kα radiation (λ
= 1.5418 Å) (Rigaku, Japan). Elemental analyses were carried
out on a PerkinElmer 2400C elemental analyzer (Elementar, Germany).
TGA data were acquired using a Mettler-Toledo simultaneous thermal
analyzer from room temperature to 800 °C under an N2 atmosphere at a heating rate of 10 °C min–1 (Netzsch, Germany). XPS was performed using a K-Alpha X-ray photoelectron
spectrometer (Thermo Scientific, USA). The morphology and energy-dispersive
spectroscopy (EDS) data of Cd-CP, Hg@Cd-CP, and Pb@Cd-CP were obtained
using a Nova NanoSEM 450 field-emission scanning electron microscope
(SEM) at 10 Kv (Thermo Scientific, U.S.A.). The concentration of metal
ions was determined with an iCAP6300 ICP-AES (Thermo Scientific, U.S.A.).