A trade-off between adsorption and photocatalysis over ZIF-derived composite.

The adsorption with highly porous adsorbents is an efficient technique to trap the uncontrolled release of antibiotics in the environment, however, mere adsorption does not mineralize the discharged antibiotics. On the contrary, the regular photocatalysts completely mineralize the antibiotics, however suffers from high efficiency due to comparatively low surface area and porosity. In this work, a balance has been made between efficient adsorption followed by complete degradation of the adsorbed antibiotic over ZIF-8 derived ZnO/N-doped carbon composite. The nitrogen-doped carbon produced at 1000 °C showed a very high adsorption capacity of SMX, due to higher surface area, porosity and better surface interaction between adsorbate and adsorbent. The ZnO formed at 600 °C produced sufficient OH· that were responsible to show a very high rate of complete photocatalytic mineralization of SMX over the material. The ZnO/N-doped carbon composite showed a very high rate of photodegradation with a corresponding rate constant of 4.36 × 10 min. The complete degradation mechanism was proposed and rates were compared with existing literature.