Table 1.
Physicochemical properties of biochars.
Table 2.
BET characteristics of biochars.
Fig 1.
Adsorption kinetic curves with different types of biochars.
Table 3.
Kinetic model parameters for the fluorine adsorption using biochars.
Fig 2.
Fluorine kinetic adsorption curves using different soil samples.
(Note: a, swine manure biochar (350°C)-treated soil; b, swine manure biochar (500°C)-treated soil; c, swine manure biochar (650°C)-treated soil; d, straw biochar (500°C)-treated soil).
Table 4.
Kinetic model parameters for the fluorine adsorption in biochar treated soils.
Fig 3.
Adsorption isotherms curves on biochars.
(Note: weight of biochar = 0.1 g, solution volume = 20 mL, pH = 7, 25°C).
Table 5.
Adsorption isotherm parameters for the fluorine adsorption using biochars.
Table 6.
Comparison of fluorine adsorption capacities for PBC650 and RBC500 with for previously reported adsorbents.
Fig 4.
Adsorption isotherms curves in biochar treated soil samples.
(Note: weight of soil = 1.0 g, solution volume = 20 mL, pH = 7, 25°C).
Table 7.
Adsorption isotherm parameters for the fluorine adsorption in biochar treated soils.
Table 8.
X2 statistics of two models.
Table 9.
Desorption isotherm parameters for the fluorine desorption in different soil samples.
Fig 5.
Adsorption curves using different biochars under different pH.
Fig 6.
Soil adsorption curves under different pH.
(Note: a, PBC350-treated soil; b, PBC500-treated soil; c, PBC650-treated soil; d, RBC500-treated soil).
Fig 7.
Effect of interfering ions at different concentrations on fluoride adsorption.
(Note: weight of biochar = 0.1 g, solution volume = 20 mL, CK is 50 mg/L of F-, interfering ions concentration = 50 mg/L、100 mg/L and 200 mg/L, pH = 7, 25°C).
Fig 8.
Infrared spectra before and after biochar adsorption.
(Note: a, PBC350-treated soil; b, PBC500-treated soil; c, PBC650-treated soil; d, RBC500-treated soil).
Fig 9.
SEM images of different types of biochars.