Mechanistic pathways and optimization of salinity-tolerant antibiotic degradation catalyzed by Gracilaria verrucosa biochar

초록

Tetracycline (TC), a commonly found antibiotic, poses ecological risks when present in aquatic environments. A low-cost activated biochar was developed from Gracilaria verrucosa (GBVC) via one-step pyrolysis (800 degrees C) and utilized to activate peroxydisulfate (PDS) for TC degradation. Under optimized conditions, GVBC800 achieved 100 % of TC degradation (TC =10 mg L1, GVBC800 =100 mg L1, PDS =1.25 mM, pH 5.0), with adaptability across a wide range of pH (3.0-11.0). TC degradation involved radical (center dot OH and SO4 center dot) and non-radical (1O2) pathways, as well as electron transfer, facilitated by pyridinic N, thiophene sulfur (S 2p3/2), and structural defects in GVBC800. In saline water, nearly 100 % TC removal was achieved using 2.5 mM of PDS and 200 mg L-1 of GVBC800. Degradation pathways were proposed and TC mineralization was evaluated, highlighting the efficacy of the GVBC800/PDS system for TC degradation in challenging environmental conditions

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