The reagents employed in this study were of high purity including zinc nitrate hexahydrate (Sigma-Aldrich, USA), imidazole (Sigma-Aldrich, USA), 2-methylimidazol (Sigma-Aldrich, USA), N,N-dimethylformamide (Honeywell, USA), tri-ethyl amine (Sigma-Aldrich, USA), sodium hydroxide (EMSURE®, USA), lead nitrate (BDH, UK), hydrochloric acid (Fisher Scientific, USA). Ultra-pure water (CORNING Mega PureTM, USA), was used for sample preparation and dilution. The glassware used was thoroughly washed, cleaned and dried before each use.
X-ray diffractometer (XRD Rigaku Miniflex-II, Japan) was used to investigate the crystal phases of the synthesized ZIF-60; current was set at 15 mA while the CuKα1 radiation was kept at 40 kV. The 2θ angle range for the analysis was set between 5 to 40° at a scanning rate of 7.00°/min. Thermal stability of ZIF-60 was tested using thermogravimetric analysis (TA Instruments) in N2 atmosphere using a heating rate of 10 °C/min in the temperature range from 30 to 800 °C. FTIR spectra were collected using Smart iTR NICOLET iS10 FTIR spectroscopy for surface functional groups investigation.
The lead concentration in the aqueous solutions was determined using atomic absorption spectroscopy (PerkinElmer, USA); the samples were passed through 0.2 µm filter (Whatmann, Germany) before subjecting them to analysis. pH measurements were conducted using OAKTON ® pH 700.
X-ray diffractometer (XRD Rigaku Miniflex-II, Japan) was used to investigate the crystal phases of the synthesized ZIF-60; current was set at 15 mA while the CuKα1 radiation was kept at 40 kV. The 2θ angle range for the analysis was set between 5 to 40° at a scanning rate of 7.00°/min. Thermal stability of ZIF-60 was tested using thermogravimetric analysis (TA Instruments) in N2 atmosphere using a heating rate of 10 °C/min in the temperature range from 30 to 800 °C. FTIR spectra were collected using Smart iTR NICOLET iS10 FTIR spectroscopy for surface functional groups investigation.
The lead concentration in the aqueous solutions was determined using atomic absorption spectroscopy (PerkinElmer, USA); the samples were passed through 0.2 µm filter (Whatmann, Germany) before subjecting them to analysis. pH measurements were conducted using OAKTON ® pH 700.