Synthesis of Zeolite-Based Cu/Fe–X from Coal Gangue for Fenton-Like Catalytic Degradation of Rhodamine B.

In this paper, coal gangue, a solid waste is used as raw material to provide silicon and aluminum sources for synthesis of zeolite. A coal gangue zeolite based Cu/Fe–X catalyst is successfully prepared by immersion-calcination method, which is used to remove Rhodamine B from aqueous solution. The characterization results show that Cu and Fe have been successfully loaded on zeolite, not damaged its structure, and these nanoparticles are highly dispersed and low crystallinity. This special structure will enhance its catalytic ability to activate H₂O₂. The experiment showed that hydroxyl radical (·OH) was the main active species for catalytic degradation of Rhodamine B, and the circulation of Cu²⁺ to Cu¹⁺ and Fe³⁺ to Fe²⁺ could synergistically produce ·OH. Furthermore, the redox potential of Cu¹⁺ and Cu²⁺ is lower than Fe²⁺ and Fe³⁺, which can promote Fe³⁺ circulate to Fe²⁺, further promote Fe²⁺ to activate H₂O₂ to decompose into ·OH, and overcome the speed limiting step of Fenton-Like catalytic reaction. The Cu/Fe–X catalyst can activate H₂O₂ in wide pH range (1–10). Under optimal conditions, the catalytic degradation rate can reach 99.9%, and the TOC removal rate is as high as 98.5%. Therefore, Cu/Fe–X/H₂O₂ system can effectively remove organic dyes, and has a high industrial application prospect. [ABSTRACT FROM AUTHOR]