In the latest issue of the Journal of Environmental Chemical Engineering, researchers present a novel approach to removing tetracycline (TC) from wastewater using a biochar/g-C3N4/BiOBr (BCN/BiOBr) heterojunction. This new method achieves an impressive 86.5% degradation of TC under visible light in just 72 minutes, a rate significantly higher than traditional g-C3N4 methods.

The research highlights the efficiency of the S-scheme heterojunction, which boosts charge separation and enhances photocatalytic performance through the synergistic effects of adsorption and photocatalysis. Key active species, including h+, ·OH, and ·O2-, play crucial roles in the degradation process, demonstrating the heterojunction’s capability in facilitating robust redox reactions.

Factors such as pHpH is a measure of how acidic or alkaline a substance is. A pH of 7 is neutral, while lower pH values indicate acidity and higher values indicate alkalinity. Biochars are normally alkaline and can influence soil pH, often increasing it, which can be beneficial More levels, the concentration of TC, and the amount of photocatalyst used were meticulously studied, revealing the heterojunction’s superior adaptability and efficiency under various conditions. This innovation not only addresses the limitations of conventional methods—like low efficiency and potential secondary pollution—but also leverages the high stability and cost-effectiveness of photocatalysis.

By exploring advanced techniques like electron spin resonance (ESR) and transmission electron microscopy (TEM), the study provides a comprehensive understanding of the degradation mechanism. The research underscores the potential of biochar-modified S-scheme photocatalysts in improving wastewater treatment, offering a promising direction for future environmental remediation efforts.