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Md Abdullah Al Masud, Ph.D. (Postdoctoral Researcher, Kyungpook National University)

Antibiotic pollution of water bodies poses a significant threat to ecosystems and human health. Ciprofloxacin (CIP), a widely used antibiotic, is particularly persistent and requires effective removal strategies. In my recent article with Won Sik Shin and Do Gun Kim in Chemical Engineering Journal, we introduce a novel approach for CIP degradation: iron-doped kelp-derived biocharBiochar is a carbon-rich material created from biomass decomposition in low-oxygen conditions. It has important applications in environmental remediation, soil improvement, agriculture, carbon sequestration, energy storage, and sustainable materials, promoting efficiency and reducing waste in various contexts while addressing climate change challenges. More (Fe-KBC) activated peroxymonosulfate (PMS).

Enhanced CIP Removal with Fe-KBC

Compared to undoped KBC, Fe-KBC exhibited significantly improved CIP removal (97.48% vs. 63.38%) under optimized conditions. This enhancement is attributed to:

• Increased electron transfer: Fe-doping introduced defects, graphitic structures, and Fe-oxides, facilitating electron (e^–) transfer from CIP to PMS.
• Enhanced radical and non-radical species generation: Fe-KBC promoted the formation of sulfate radicals (SO₄^·-) and singlet oxygen (¹O₂), key oxidants for CIP degradation.
• Improved mineralization: Fe-KBC/PMS system showed significant effectiveness in mineralizing CIP, achieving a 75.06% (TOC). This indicates that CIP was predominantly broken down into carbon dioxide (CO₂) and water (H₂O).
• Degradation mechanism: Reactive oxygen species (ROS) such as SO₄^·- and ¹O₂ were identified as the primary drivers of CIP degradation. The Fe-doping mechanism involved substituting H⁺ in CHx and K⁺, as well as bonding with O in C–O.

Fe-KBC’s Potential for Practical Application

• Reusability: Fe-KBC maintained good performance over multiple cycles, demonstrating its feasibility for long-term use.
• Tolerance to co-existing ions: K⁺, Na⁺, Ca²⁺, Cl^–, and SO₄^2- had minimal impact on CIP degradation, indicating broad applicability in diverse water matrices.
• NGW Compatibility: Although Mg²⁺, HCO₃^–, H₂PO₄^–, HA, and natural groundwater reduced performance, simply increasing PMS dosage effectively restored it.

Iron-doped kelp biochar/PMS system provides a promising, green approach for efficient ciprofloxacin degradation. Its advantages, including high performance, reusability, and tolerance to various ions, highlight its potential for practical application in wastewater treatment and environmental remediation. This study paves the way for further development of sustainable strategies for addressing antibiotic pollution using biochar-based catalysts.

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Al Masud, Shin, & Kim (2023) Fe-doped kelp biochar-assisted peroxymonosulfate activation for ciprofloxacin degradation: Multiple active site-triggered radical and non-radical mechanisms. Chemical Engineering Journal, Vol 471. https://doi.org/10.1016/j.cej.2023.144519