Micro-Octahedron Cu₂O-Based Photocatalysis-Fenton for Organic Pollutant Degradation: Proposed Coupling Mechanism in a Membrane Reactor

Abstract

The degradation efficiency of organic pollutants was enhanced with the combination of visible-light photocatalysis and Fenton catalysis upon the dual-functional catalyst Cu 2 O. As-prepared micro-octahedrons of Cu 2 O enclosed with eight (111) facets were proved to have photoactivity and Fenton activity. It was found that the decolorization rate of methyl blue (50 mg/L) in water increased from 68% in the photocatalysis process to 92% in the combined photocat-Fenton process for 120 min. The reaction duration was remarkably shortened from 120 to 20 min by membrane feeding of H 2 O 2 . The degradation reaction rate constant showed a 10-fold increase at k = 0.200 min −1 in the membrane-assisting visible/Cu 2 O/H 2 O 2 system. The reduction of chemical oxygen demands (CODs) in industrial paper-mill wastewater (CODs = 813 mg/L) was 79% using the membrane-intensified oxidation approach. A synergistic merge of photoredox and copper catalysis could be realized upon fast collision, micromass transfer, and efficient electron transfer. The facet-dependent oxidation coupling mechanism is proposed to explain the mutual stimulating effect. Hence, the photocatalysis-Fenton membrane process is powerful to degrade persistent organic pollutants in water and wastewater.

Insights into the Degradation Mechanisms of TCH by Magnetic Fe3S4/Cu2O Composite

“…It can be clearly seen from the image that pure Cu 2 O is a regular cube, which is consistent with the characterization described in the literature. 41 Figure 3c shows the morphological characteristics of the Fe 3 S 4 /Cu 2 O composite and the successful growth of small Cu 2 O particles on the surface of the Fe 3 S 4 .…”

In Situ Synthesis of Cu2O Nanoparticles Using Eucalyptus globulus Extract to Remove a Dye via Advanced Oxidation

“…In this mechanism, the Cu(I)/Cu(II) half-cycle facilitates the reduction of H2O2 to •OH and OH − (Equation (1)). Simultaneously, the Cu(II)/Cu(I) half-cycle enables the oxidation of H2O2 to hydrogen peroxide radicals (HO2•) or •O2 − depending on the pH of the system, constituting the speed-limiting step (Equation ( 2)) [7]. Notably, the kinetics difference observed in the copper Fenton-like process is approximately 50-100 times less than that of the ferrous Fenton process, rendering copper Fentonlike catalysis significantly more efficient [7].…”

Improved Spherical Particle Preparation of Ceftriaxone Sodium via Membrane-Assisted Spherical Crystallization

“…Recently, membrane separation technology coupled with other separation technologies has been widely used in many fields as a new and efficient separation technology to enhance mass transfer and separation efficiency. − Ma et al , developed two membrane emulsification techniques to prepare uniform spherical particles with controllable size. By direct membrane emulsification, the dispersed phase was forced through the membrane with the precisely controlled pressure and detached from the membrane under the flow of the continuous phase to form a homogeneous emulsion .…”