Isolating micro/nanoplastics from organic-rich wastewater: Co/PMS outweighs Fenton system.

Rapid isolation of microplastics is the prerequisite for correct and in-depth understanding of their environmental impacts and human health threats. And Fenton's reagent (Fe/HO system, FHS) has been proven to be a viable way to isolate microplastics from wastewater, but it is limited because of harsh reaction conditions, long reaction time and low efficiency. Herein, it's proven that the Fenton-like system, which is using Cobalt (II) salts to decompose potassium peroxymonosulfate (Co/PMS system, CPS) with generation of O, can offer shorter time (within 30 min) in complex sample isolation. The experimental results showed that the isolation time of micro/nanoplastics from pollutants with CPS in only 30 min, while it was at least more than 5 h with FHS. Via a serious of experiments of comparison and characterization between FHS and CPS, whether from the point of view of reaction time or isolation effect, CPS is superior to FHS. On this basis, we validate the applicability of this system (CPS) in different reaction conditions (concentration, pH), different sizes (from microns to nanometers) and types of plastic (PS, PA, PE, PP, PVC). In addition, the CPS can also preserve the integrity of the plastic itself and reduce the impact on the quality of samples evidenced by a variety of characterization of physicochemical structure like UV-vis, TEM, AFM, FTIR and XPS. CPS is proved to be faster, higher, stronger for enhancing the isolation of micro/nanoplastics from complex matrix. In a word, this study provides a promising solution for the efficient isolation of microplastics from wastewater without causing additional harm to the plastics.