Peroxymonosulfate Activation by Facile Fabrication of α-MnO2 for Rhodamine B Degradation: Reaction Kinetics and Mechanism

Abstract

The persulfate-based advanced oxidation process has been an effective method for refractory organic pollutants’ degradation in aqueous phase. Herein, α-MnO2 with nanowire morphology was facially fabricated via a one-step hydrothermal method and successfully activated peroxymonosulfate (PMS) for Rhodamine B (RhB) degradation. Influencing factors, including the hydrothermal parameter, PMS concentration, α-MnO2 dosage, RhB concentration, initial pH, and anions, were systematically investigated. The corresponding reaction kinetics were further fitted by the pseudo-first-order kinetic. The RhB degradation mechanism via α-MnO2 activating PMS was proposed according to a series of quenching experiments and the UV-vis scanning spectrum. Results showed that α-MnO2 could effectively activate PMS to degrade RhB and has good repeatability. The catalytic RhB degradation reaction was accelerated by increasing the catalyst dosage and the PMS concentration. The effective RhB degradation performance can be attributed to the high content of surface hydroxyl groups and the greater reducibility of α-MnO2, and the contribution of different ROS (reactive oxygen species) was 1O2 > O2·− > SO4·− > ·OH.

Near-Infrared-Driven β-NaYF4:Yb,Tm,Gd/Ni-MOF Nanocomposites for Efficient Sterilization and Degradation of Organic Contaminants

“…As the concentration of RhB increased, the limited active sites of UNM are occupied by more RhB molecules, resulting in a gradual decrease in degradation efficiency . It is important to determine a reasonable concentration range, and after reviewing the literature, it was concluded that 10–20 mg/L would be suitable. , The maximum degradation speed and rate within this concentration range were observed when the original concentration of RhB is 10 mg/L, as shown in the kinetic fitting diagram (Table S3). This result is very similar to the degradation speed and rate seen at an initial RhB concentration of 5 mg/L.…”