Tetracycline removal from soil by phosphate-modified biochar: Performance and bacterial community evolution

Area of Science:

• Environmental Science
• Soil Science
• Materials Science

Background:

• Original biochar shows limited effectiveness in remediating soil tetracycline pollution.
• Existing modified biochar methods are often costly, complex, or environmentally unfriendly for soil application.

Purpose of the Study:

• To develop a cost-effective and environmentally friendly phosphate-modified biochar for enhanced tetracycline adsorption in soil.
• To investigate the impact of pyrolysis temperature and phosphate type on biochar modification for tetracycline remediation.
• To evaluate the efficacy of the optimal modified biochar in remediating tetracycline-contaminated soil and improving soil properties.

Main Methods:

• Corn stover-derived biochar was modified using various phosphate types (e.g., K3PO4) and pyrolysis temperatures (up to 800°C).
• Surface morphology, pore structure, and functional groups of modified biochar were analyzed using SEM, BET, and FTIR.
• Adsorption capacity of tetracycline by modified biochar was determined.
• The optimal modified biochar (K3PO4-800) was applied to contaminated soil for remediation assessment.

Main Results:

• Phosphate modification significantly enhanced the adsorption capacity of biochar for tetracycline compared to original biochar.
• Pyrolysis temperature and phosphate anion type critically influenced biochar performance, with K3PO4 and 800°C yielding the highest adsorption (124.51 mg/g).
• K3PO4-800 modified biochar effectively reduced soil tetracycline concentration, improved soil potassium and phosphorus levels, and positively altered microbial communities.

Conclusions:

• Phosphate modification, particularly with K3PO4 at high temperatures, creates a superior material for tetracycline adsorption.
• K3PO4-800 modified biochar serves as both an effective adsorbent for tetracycline and a beneficial soil amendment.
• This approach offers a promising, eco-friendly solution for managing antibiotic contamination in agricultural soils.