ZnO‐based composite catalysts for photocatalytic degradation of reactive black 5, and the optimization of process parameters

Abstract

Dye contaminated wastewaters show serious harm to the environment, and therefore, they have been becoming the focus of environmental protection and scientific research. In this study, the removal of reactive black dye from the contaminated solution was investigated by photo Fenton-like degradation process using ZnO-based composite catalysts. Ag/ZnO and Fe 2 O 3 /zeolite/ZnO composites show the more efficient catalysts with degradation efficiencies of about 99%. The effects of four different process parameters on the degradation efficiency of reactive black dye, and the simultaneous interactions between the parameters were investigated using the Box-Behnken design (BBD) of response surface method (RSM). Maximum removal efficiency of 99% is obtained in pH = 3, dye concentration of 10 ppm, 0.05-g dose of catalyst and 40 C reaction temperature. The removal efficiency of Fe 2 O 3 /zeolite/ ZnO catalyst after four replicating experiments is 63%. Based on the reported results, the prepared catalyst can be used efficiently in the wastewater treatment industries.

Review on cobalt ferrite as photo-Fenton catalysts for degradation of organic wastewater

“…Traditional semiconductor catalysts such as TiO 2 and ZnO have been widely studied due to their cheapness, nontoxicity, high stability, and high electron mobility. 43,44 However, most of these semiconductor materials have large band gaps, 45 which leads to their good catalytic activity only under UV light. As we all know, the ultraviolet spectrum makes up only about 7% of the total spectrum of sunlight, which will seriously limit the use environment of catalysts.…”

Two‐Dimensional BiOBr Nanosheets Coupled with FeOOH Quantum Dots as Composite Photo‐Fenton Catalysts for Organic Pollutant Degradation under Visible Light

“…These electrons and holes can react with H 2 O and O 2 to generate superoxide radicals (⋅O 2 − ) and hydroxyl radicals(⋅OH), thereby realizing the mineralization of organic pollutants [18] . Traditional catalysts with excellent performance usually have wide optical band gaps [19,20] . This will make them only absorb ultraviolet light (UV) with a wavelength of less than 400 nm, which seriously limits their application and development as photocatalytic materials [21] .…”