Removal of benzo(a)pyrene in polluted aqueous solution and soil using persulfate activated by corn straw biochar.

An activator, corn straw biochar, was produced and applied in persulfate-based oxidation to remove benzo(a)pyrene (BaP) in polluted aqueous solution and soil. Polluted aqueous solution remediation results showed that at pH 7, approximately 88.4% of BaP was removed by 10 mM of persulfate activated by 1.6 g/L of biochar, and degradation played a dominant role. Polluted soil remediation results demonstrated that the activated persulfate solution (at 9 g/L) by biochar (at 3 wt% of soil) can remove 93.2% of BaP. In remediation of BaP-polluted soil, increasing biochar dosage and persulfate concentration accelerated BaP degradation to some extent, while excessive biochar or persulfate inhibited the degradation of BaP probably due to the unnecessary SO consumption. The biochar-activated persulfate oxidation reflected a good performance in tolerating the influences of background electrolytes (such as HCO, Cl, and humic acid (HA)) in soil on BaP remediation. In addition, in the removal of BaP by the oxidation systems activated by biochar, persulfate was proved as a superior oxidant compared to peroxymonosulfate and HO, and the removal efficiencies of BaP were 93.2%, 86.5%, and 84.4% under the same treatment condition. To sum up, the biochar-activated persulfate oxidation would be a potential application in remediation of BaP-polluted aqueous solution and soil.