Simultaneous Removal of Sulfamethazine, Zinc, and Copper UsingWaste Prestressed Concrete Sleepers and Persulfate

초록

Simultaneous removal of antibiotics and heavy metals from livestock wastewater remains technically challenging because of their distinct removal mechanisms. This study investigates the synergistic use of calcined waste prestressed concrete (CPC) and persulfate (PDS) for the concurrent removal of sulfamethazine (SMZ), Cu2+, and Zn2+. Calcination of waste prestressed concrete (PC) sleepers at 800 ℃ eliminated residual organic contaminants and converted Ca(OH)2 and CaCO3 into reactive CaO, thereby maximizing hydroxide release. The resulting CPC induced rapid alkalinization, enabling complete precipitation of Cu2+ and Zn2+. Simultaneously, the elevated pH activated PDS, generating hydroxyl radicals that efficiently degraded SMZ. However, in co-contaminated systems, excessive CPC dosing inhibited SMZ removal by prematurely precipitating Cu2+, a key catalyst for PDS activation. Continuous-flow-through experiments further confirmed the operational stability and practical applicability of CPC, demonstrating superior heavy-metal removal performance compared to uncalcined PC. Overall, CPC functions as an effective upcycled alkaline agent for the integrated removal of heavy metals and antibiotics, highlighting the importance of balancing precipitation and catalytic activation processes.

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