Effect of HPO-modified biochar on the fate of atrazine and remediation of bacterial community in atrazine-contaminated soil.

The application of chemically modified biochar is a promising strategy for the remediation of contaminated (e.g., pesticides) soil. In this study, HPO was used to modify peanut shell to improve the remediation performance of biochar. Surface area (980.19 m/g), pore volume (0.12 cm/g), and the functional groups (OH, CO, and phosphorus-containing groups) on the biochar were increased by HPO treatment. The sorption experimental data were well fitted by Freundlich model, while the sorption affinity (K) of HPO modified biochar (PBC) for atrazine was 128 times greater than that of the untreated biochar (BC) in the aquatic systems. The K values of PBC-amended soil to atrazine were increased by 13.57 times than that of single soil. The strong sorption of PBC on atrazine delayed the degradation of atrazine in soil, and the residual percentage of atrazine in soil and soil-PBC mixture were 4.90% and 71.44% at the end of 60-day incubation, with the degradation half-life increased from 13.3 to 121.6 d. The analysis of high-throughput sequencing results showed that atrazine reduced the diversity of soil microbial community, but the abundance of microorganisms with degradation function increased and became dominant species. The addition of PBC in soil accelerated the microbial remediation of atrazine stress, which may promote the soil nitrogen cycle. Therefore, amendment of atrazine contaminated soil with PBC can reduce the environmental risk of atrazine and benefit the soil microbial ecology.