Improvement of dyes degradation using hydrofluoric acid modified biochar as persulfate activator

Figures & data

Table 1. Selected properties of BC and HF-BC.

	BC	HF-BC
Yield(%)	39.0	24.8
pH	9.56	6.21
C(%)	48.0	83.0
H(%)	1.62	2.02
H/C	0.40	0.29
SA (m^2 g^−1)	131	355
MV(cm^3 g^−1)	0.057	0.155
APD (nm)	2.52	2.02
Carboxyl(mmol g^−1)	0.21	0.26
Lactonic group(mmol g^−1)	0.24	0.11
Phenolic hydroxyl group(mmol g^−1)	0.02	0.03

SA, BET-N₂ surface area; MV, micropore volume; APD, average pore diameter.

Table 2. The surface atomic composition of BC and HF-BC.

	BC	HF-BC
C(%)	85.33	91.19
O(%)	12.04	8.74
F(%)	-	0.06
Si(%)	2.63	0.01

- below detection limit

Figure 1. SEM images with EDX of BC and HF-BC.

Figure 2. FTIR spectra of the BC and HF-BC.

Figure 3. Decolorization of AO7 by biochar/PS system.

Figure 4. Effect of PS concentration on the decolorization of AO7 by HF-BC/PS system. HF-BC dosage = 5.0 g/L, PS/AO7 molar ratio = 50/1–700/1.

Figure 5. Effect of HF-BC dosage on the decolorization of AO7 by HF-BC/PS system. PS/AO7 molar ratio = 100/1, HF-BC dosage = 1g/L-10 g/L.

Figure 6. Effect of initial pH on the decolorization of AO7 by HF-BC/PS system. PS/AO7 molar ratio = 100/1, HF-BC dosage = 5 g/L.