Ultrasound-Assisted for Super-Rapid and High-Efficient Adsorption and Desorption

Adsorption-desorption technology is the basis of numerous environmental processes and industries in modern society. Undoubtedly, improving adsorption rates and renewability of sorbents can positively impact productivity. It is herein showed that poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) presented remarkable adsorption kinetics and regeneration efficiency under ultrasound. The pseudo-first-order adsorption rate constant for Rhodamine B (RhB) is 2.7753 min^-1, with an initial adsorption rate 7,000-23,000 times higher than commercial activated carbon. Meanwhile, the polymer achieves over 90% removal of the antibiotic levofloxacin (LEV) and the persistent pollutant perfluorooctanoic acid (PFOA) within 5 min. Impressively, complete desorption occurs within 2 min by simply changing the solvent, and the performance is retained across at least 20 adsorption-desorption cycles. It is proposed that, under ultrasound, the low interface tension of PVDF-HFP may accelerate solute diffusion by disrupting the liquid film, while the ferroelectric PVDF-HFP generates a built-in electric field to enhance adsorption. This research suggested an alternative strategy for developing high-performance adsorption-desorption techniques.