Synthesis of flower-like CoOOH with hierarchical micro/nano-structure as a catalyst for peroxymonosulfate activation

Abstract

In this work, hierarchical flower-like CoOOH assembled from many nanoflakes with a thickness of 20 nm was fabricated by a simple chemical bath deposition (CBD) method, and its performance as a heterogenous catalyst to activate peroxymonosulfate (PMS) for degradation of methylene blue (MB) solution was explored. The results show that CoOOH/PMS is a high efficient system for MB removal, in which 91.95% degradation of MB can be realized within 25 min. Influences of process parameters, including dosage of PMS, addition of catalyst, and co-existed anions on MB degradation were also investigated. It is found that the degradation rate of MB increases with the increase of the amount of PMS from 0.15 mmol·L-1 to 0.45 mmol·L-1. In such PMS concentrations ranges, CoOOH catalyst amount of 0.03 g·L-1 is adequate for PMS activation in the reaction system. The presence of Cl-1and HCO3- anions has a negative effect on MB degradation, while SO42- has no significant influence. In addition, quenching experiments were conducted and SO4 ·- is confirmed as the main active specie during the MB degradation process. Moreover, cycling runs proven that CoOOH could be re-used to activate PMS for MB degradation without notable activity reduction. These results suggest that hierarchical CoOOH is a promising PMS activator for organic pollutant removal.