Foam-gelcasting combined with catalytic nitridation preparation of Si3N4/BN porous ceramics with hierarchical pore structures for efficient ciprofloxacin and atenolol removal

Pharmaceutical compounds are increasingly recognized as emerging contaminants that pose substantial risks to aquatic environments and human health. In this study, hierarchical Si 3 N 4 /BN porous ceramics (SNBNPCs) adsorbents with a nanofibrous-granular composite architecture, comprising boron nitride (BN) fibers and Si 3 N 4 , were fabricated through a foam-gelcasting method followed by in-situ nitridation. Utilizing silicon, melamine, and boric acid as precursor materials, Fe(NO 3 ) 3 ·9H 2 O as a catalyst (1 wt%), the synthesis was conducted at a relatively low temperature of 1573 K for 5 hours. The adsorbents were subsequently assessed for their efficacy in removing ciprofloxacin (CIP) and atenolol (ATL) from aqueous solutions. The synthesized SNBNPCs exhibited a density of 0.24 g/cm 3 and a compressive strength of 1.6 MPa. Under the experimental conditions (initial concentration C₀ = 10 mg/L, pH = 7, temperature 295 ± 3 K), the aerogel demonstrated rapid adsorption kinetics and achieved removal efficiencies exceeding 97.5% for both CIP (98.0%) and ATL (97.7%), even at a low adsorbent dosage of 250 mg/L. The maximum adsorption capacities were determined to be 21.2 mg/g for CIP and 14.5 mg/g for ATL at the specified initial concentration. Given its notable mechanical robustness, favorable recyclability, and high adsorption performance toward these pharmaceutical contaminants, the synthesized SNBNPCs composite presents considerable potential as an effective adsorbent for the remediation of similar emerging contaminants in water treatment applications.