Hydraulic-driven piezo-activation of peroxymonosulfate for carbamazepine degradation with ultralow energy consumption

Abstract

Although peroxymonosulfate (PMS) coupling with ultrasonic piezo-catalysis (PE) or electrolysis (E) exhibited satisfactory efficiency of organics degradation by generating more reactive species, the relatively high energy consumption restricted their application. Hydro-energy, as a clean energy resource, is available in water treatment and transportation processes. Herein, a hydraulic-driven PE-PMS process was proposed, using barium titanate as piezoelectric material for carbamazepine (CBZ) degradation. Results showed that CBZ was efficiently degraded (76.17%, 180 min) in the PE-PMS process with a pseudo-first-order rate constant of 8.15 × 10−3 min−1. Moreover, the degradation ratio of CBZ was still up to 64.19% after 10 cycles without valence and crystal phase changes. Importantly, the energy consumption of the hydraulic PE-PMS process (428.65 kWh m−3 order−1) was only 2.56% and 22.87% of ultrasonic PE-PMS and traditional E-PMS processes, respectively. Finite element method and electrochemical measurement were performed to understand the influence of the hydraulic gradient (G). A positive correlation between G and piezo-potential/current was found in the hydraulic PE-PMS process. However, there was an optimal G value (7.72 s−1) for CBZ degradation. Further studies showed that ·OH played a major role in CBZ degradation during the hydraulic PE-PMS process. Various refractory organics could be effectively degraded in this process, while a satisfactory degradation of CBZ was observed in the actual water matrices. Therefore, the hydraulic-driven PE-PMS system might be an efficient, sustainable, and energy-saving process for water treatment by the potential utilization of residual hydro-energy in water transportation.