Effect of pyrolysis temperature on adsorption and degradation of THI and IMI by biochar

In order to explore the effects of biochar prepared at different pyrolysis temperatures and different solid-liquid ratios on the adsorption and degradation of thiacloprid and imidacloprid in biochar, three biochar were prepared by oxygen pyrolysis with sawdust and as raw materials at 300, 500 °C and 600 °C respectively. The effects of biochar on the adsorption degradation of thiacloprid and Imidacloprid in biochar were studied. The results showed that the addition of biochar could significantly increase the soil pH, available phosphorus and organic carbon content, and reduce the soil H / C. The addition of biochar significantly improved the adsorption of thiacloprid and imidacloprid, and the adsorption capacity increased with the increase of biochar pyrolysis temperature. Biochar with different pyrolysis temperatures had different effects on the degradation of thiacloprid and imidacloprid. The strong adsorption capacity of high temperature biochar system reduces the chemical degradation rate of thiacloprid and imidacloprid. Proper solid-liquid ratio can avoid the waste of adsorbent and achieve the optimal utilization rate. Therefore, the types and properties of biochar should be fully considered when using biochar to repair pesticide contaminated soil.