The graceful art, significant function and wide application behavior of ultrasound research and understanding in carbamazepine (CBZ) enhanced removal and degradation by Fe0/PDS/US.

Carbamazepine (CBZ) antibiotic organic contamination wastewater poses a huge threat to environmental safety. An advanced oxidation technology (Fe0/PDS/US) of using ultrasound (US) enhanced zero-valent iron/potassium persulfate (Fe0/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 Fe0 dosage on the removal of CBZ. In addition, we also investigated into the effect of background ions (PO43-, HCO3-, Cl- and HA) on Fe0/PDS/US and analyzed the related results. The mechanism of CBZ removal in Fe0/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 Fe0/PDS. It has prominent performance in catalytically degrading CBZ when the pH is 10.0. SO4•-, •OH and O2•- all coexist in the Fe0/PDS/US and make contribution to CBZ removal, whereas the SO4•- 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•- 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 biodegradation of products. The Fe0/PDS/US is of great potential application value in removal of organic pollution and environmental purification.