Fig 1.
Effect of different mass ratios on the adsorption properties of phosphate (P concentration = 100 mg/L, pH = 7, material dosage = 1 g/L, T = 25 ± 2.5 °C).
Fig 2.
(a) The SEM image of SBC, (b-c) The SEM image of ESBC-1, (d-f) The EDS elemental diagram of ESBC-1 and (i) the Mapping spectrum of ESBC-1.
Table 1.
Comparison of SBET, Total pore volume, and APD for SBC, ESBC-1, and ESBC-1-P (after phosphate adsorption).
Fig 3.
(a) Adsorption and desorption curve, (b-d) FTIR spectra, XRD patterns, and XPS spectra of SBC and ESBC-1.
Table 2.
The elemental composition (atomic %) measured by XPS.
Table 3.
Parameters of adsorption isotherm models for phosphate adsorption by ESBC-1 and SBC at 298 K.
Fig 4.
(a-b) Adsorption isotherm models fitting for phosphate adsorption by SBC and ESBC-1, (c) Kinetic models fitting for phosphate adsorption by SBC, (d) Kinetic models fitting for phosphate adsorption by ESBC-1 (P concentration = 100 mg/L, pH = 7, material dosage = 1 g/L, T = 25 ± 2.5 °C).
Table 4.
ESBC-1 and SBC adsorption kinetic parameters of phosphate.
Fig 5.
(a) Effect of dosage on phosphate adsorption, (b) Effect of initial pH on phosphate adsorption by ESBC-1, (c) Effect of coexisting ions on phosphate adsorption, (d) Phosphate adsorption performance of ESBC-1 and SBC in real biogas slurry (P concentration = 100 mg/L, initial pH = 7, material dosage = 1 g/L, T = 25 ± 2.5 °C unless specified differently).
Fig 6.
SEM-EDS image of ESBC-1 after phosphate adsorption.
Fig 7.
(a) FTIR spectra of ESBC-1 before and after phosphate adsorption, (b) XRD spectra of ESBC-1 before and after phosphate adsorption.
Fig 8.
(a) XPS spectra of ESBC-1 before and after phosphate adsorption, (b) Ca 2p spectra of ESBC-1 before phosphate adsorption, (c) Ca 2p spectra of ESBC-1 after phosphate adsorption, (d) P 2p spectra of ESBC-1 after phosphate adsorption.