Fig 1.
XRD patterns of ZIF-8, ZIF-(2Zn:1Fe), and ZIF-(1Zn:1Fe).
Fig 2.
FT-IR spectra of ZIF-8, ZIF-(2Zn:1Fe), and ZIF-(1Zn:1Fe).
Fig 3.
SEM images of ZIF-(2Zn:1Fe) at different scales.
Fig 4.
Full XPS spectra of ZIF-(2Zn:1Fe).
Fig 5.
Nitrogen adsorption-desorption isotherm (a) and pore size distribution (b) of ZIF-(2Zn:1Fe).
Fig 6.
Effects of contact time on phosphate concentration in solution (a) and adsorption amount (b); pseudo-first-order model (c) and pseudo-second-order model (d). Experimental conditions: [PO43-]0 = 19.02 mg/L, dosage: 0.5 g/L, T = 298 K, pH = 7.0, t = 24 h.
Table 1.
Kinetics parameters of two kinetic models (Fig 6).
Fig 7.
Adsorption isotherm of ZIF-(2Zn:1Fe) (a) and Langmuir model and Freundlich model (b). Experimental conditions: [PO43-]0 = 10.0–50.0 mg/L, dosage: 0.5 g/L, T = 298 K, pH = 7.0, t = 24 h.
Table 2.
Isotherm parameters of two isothermal models (Fig 7).
Table 3.
Comparison of PO43- adsorption capacity with reported adsorbents.
Fig 8.
Effects of adsorbent dosage (a), initial solution pH (b), coexisting ions (c), and ionic strength (b) on PO43- adsorption. Experimental conditions: [PO43-]0 = 20.0 mg/L, dosage: 0.5 g/L, T = 298 K, pH = 7.0, t = 24 h.
Fig 9.
SEM images (a, b), EDX spectra (c), and atomic fractions of ZIF-(2Zn:1Fe)- PO43- as percentage (d).
Fig 10.
FT-IR spectra and XRD patterns of ZIF-(2Zn:1Fe) before and after use.
Fig 11.
Full XPS spectrum (a), P 2p XPS spectrum of ZIF-(2Zn:1Fe)- PO43- (b); Fe 2p XPS spectra (c, d) and Zn 2p XPS spectra (e, f) of ZIF-(2Zn:1Fe) and ZIF-(2Zn:1Fe)- PO43-.