The graceful art, significant function and wide application behavior of ultrasound research and understanding in carbamazepine (CBZ) enhanced removal and degradation by Fe~0/PDS/US

摘要

Carbamazepine (CBZ) antibiotic organic contamination wastewater poses a huge threat to environmental safety. An advanced oxidation technology (Fe-0/PDS/US) of using ultrasound (US) enhanced zero-valent iron/potassium persulfate (Fe-0/PDS) can remove CBZ effectively. The optimal reaction conditions were determined by exploring the effect of single-factor experimental conditions such as ultrasonic power, ultrasonic frequency, CBZ concentration, solution pH, PDS dosage, and Fe-0 dosage on the removal of CBZ. In addition, we also investigated into the effect of background ions (PO43-, HCO3-, Cl- and HA) on Fe-0/PDS/US and analyzed the related results. The mechanism of CBZ removal in Fe-0/PDS/US were explored by analyzing CBZ removal efficiency and reaction rates, the ion concentration of S2O82-, SO42-, Fe2+ and Fe3+, pH and the active radicals. The result indicates that US can improve the efficiency of activated PDS and expand the pH range of Fe-0/PDS. It has prominent performance in catalytically degrading CBZ when the pH is 10.0. SO4 center dot-, (OH)-O-center dot and O-2(center dot-) all coexist in the Fe-0/PDS/US and make contribution to CBZ removal, whereas the SO4 center dot- plays a key role. US can greatly promotes the degradation of target pollutant CBZ by speeding up the dissolution of the outer portion of iron powder, producing sufficient amount of Fe2+ with a continuous and stable way, and better activating S2O82- to generate sufficient SO4 center dot- radicals. The degradation of CBZ may embrace three reaction processes, in which organic intermediate products with low molecular weight and biological toxicity is produced, boosting further mineralization and