N-doped metal-free biochar activation of peroxymonosulfate for enhancing the degradation of antibiotics sulfadiazine from aquaculture water and its associated bacterial community composition

Synthetic antibiotic sulfadiazine (SDZ) in water streams is an increasing concern for its known adverse effects on ecosystems, therefore effective decontamination strategy is of utmost priority. Herein, nitrogen-doped coconut shell biochar (NCSBC) was synthesized as a heterogeneous catalyst to activate peroxymonosulfate (PMS) for SDZ degradation in aquaculture water. The dopant precursor consists of 1:1 w/w mixture of urea and coconut-shell. The NCSBC/PMS system achieved a maximum SDZ removal of 94% under optimum operating conditions of SDZ concentration of 0.05 mM, NCSBC dosage of 150 mg/L, and neutral pH. The synergistic effect between functionalized N moieties (combination of pyridinic-N, pyrrolic-N, and graphite-N) of NCSBC and radical (SO4 center dot-/ HO center dot) and/or nonradical (O-1(2)) processes involving the electron transfer reaction in hybrid NCSBC/PMS system aided in SDZ removal. NCSBC remained highly functioning after five consecutive cycles. Salinity and inorganic ions present in the aquaculture water did not significantly influence SDZ degradation. PCR sequencing analysis showed that Aquimonas, belonging to phylum Proteobacteria, was the most bountiful genus in the NCSBC/PMS treated water. The present study offers an innovative biowaste-to-resource strategy and demonstrates the potential of functional NCSBC in PMS activation toward the removal of SDZ from aquatic environments.

Automated summary

The synthetic antibiotic sulfadiazine (SDZ) in water streams has become a growing concern due to its negative effects on ecosystems. Therefore, finding effective decontamination strategies is crucial. In this study, nitrogen-doped coconut shell biochar (NCSBC) was synthesized as a catalyst to activate peroxymonosulfate (PMS) for SDZ degradation. The results showed that the NCSBC/PMS system achieved a high removal rate of SDZ under optimum operating conditions.