Remediating thiacloprid-contaminated soil utilizing straw biochar-loaded iron and manganese oxides activated persulfate: Removal effects and soil environment changes

Thiacloprid (THI) has accumulated significantly in agricultural soil. Herein, a novel approach to removing THI was explored by straw biochar-loaded iron and manganese oxides (FeMn@BC) to activate the persulfate (PS). The factors influencing the removal of 5 mg kg-1 THI from the soil by FeMn@BC/PS were investigated, including FeMn@BC dosing, PS dosing, temperature, and soil microorganisms. The feasibility was demonstrated by the 75.22% removal rate of THI with 3% FeMn@BC and 2% PS at 7 days and a 92.50% removal rate within 60 days. Compared to the THI, NH4+-N and available potassium were 3.96 and 3.25 times, and urease and phosphatase activities were increased by 22.54% and 33.28% in the FeMn@BC/PS at the 15 days, respectively. THI was found to seriously alter the structure of the genus in the 15 days by 16 S rRNA analysis; however, the FeMn@BC/PS group alleviated the damage, compared to the THI with 658 more operational taxonomic units. Actinobacteriota accounted for 51.48% of the microbial community in the FeMn@BC/PS group after 60 days, possibly converting transition products of THI into smaller molecules. This article provides a novel insight into advanced oxidative remediation of soils.

Automated summary

This study explored a novel approach to removing thiacloprid from agricultural soil using straw biochar-loaded iron and manganese oxides for persulfate activation. The results showed that a removal rate of 75.22% could be achieved within 7 days using 3% FeMn@BC and 2% persulfate, and a removal rate of 92.50% could be achieved within 60 days. Additionally, the FeMn@BC/PS group increased the levels of ammonium nitrogen and available potassium in the soil, as well as the activity of urease and phosphatase. Moreover, the FeMn@BC/PS group alleviated the damage to the soil microbial community caused by thiacloprid. The findings of this study provide a new insight into advanced oxidative remediation of soils.