The roles of effluent organic matters, inorganic ions, and their interplay in affecting antibiotic degradation by an electroactive membrane

The electroactive membrane (EM) technology can effectively degrade antibiotics. However, impacts of different coexisting contaminants in real wastewater on the degradation of antibiotics of EMs lacks deep understanding. Based on real membrane bioreactor (MBR) effluent, this study differentiated the impacts of organic and inorganic fractions on sulfamethoxazole (SMX) degradation of an EM. In the MBR effluent, the SMX removal rate was only ∼ 27 mg/(m 2 ·h), significantly lower than that in the synthetic feed (∼ 677 mg/(m 2 ·h)). Small effluent organic matters (EfOMs) were identified as the key contributors that suppressed SMX degradation. Two primary mechanisms were confirmed, one being their reactivity on the EM, and the other being their attachment onto the EM that covered the reactive sites. On the other hand, positive impacts were found for large EfOMs and inorganic ions besides their negative impacts. The deposition of large EfOMs and inorganic precipitates on the EM surface partly prevented small EfOMs from covering interior reactive sites of the EM, and these fouling layers also extended the SMX retention time within the EM by remarkably decreasing the membrane flux. These results highlight the importance of carefully selecting pretreatment processes for EMs to mitigate the impacts of coexisting contaminants on antibiotic degradation.