Efficient degradation of diuron using Fe-Ce-LDH/13X as novel heterogeneous electro-Fenton catalyst

Abstract

• Fe-Ce-LDH was successfully loaded onto the defect sites of molecular sieve (13X). • Excellent diuron removal was achieved with Fe-Ce-LDH/13X in EF process. • The possible heterogeneous degradation pathways for diuron are proposed. • Improved H 2 O 2 utilization was responsible for the efficient catalytic performance. • More active sites were responsible for the efficient catalytic performance. The heterogeneous electro-Fenton process is an effective technology to remove organic pollutants. However, developing efficient heterogeneous electro-Fenton catalysts remains challenging. In this paper, an iron-cerium layered double hydroxide (Fe-Ce-LDH) was successfully loaded via a solvothermal method onto the defect sites of the molecular sieve 13X to form a novel heterogeneous catalyst (Fe-Ce-LDH/13X). The catalytic performance of Fe-Ce-LDH/13X was evaluated in the heterogeneous electro-Fenton (EF) degradation of diuron. Compared with a traditional powder catalyst, this catalyst was easier to recycle and exhibited good stability. The layered structure of the catalyst provided more active sites. Doping with Ce greatly improved the catalytic performance of the catalyst, which was caused by the synergistic effect of Ce and Fe. At a molar Fe to Ce ratio of 7:3, diuron could be completely degraded within 60 min. According to the catalytic mechanism, the hydroxyl radical ·OH is the main reactive species. Possible degradation pathways in the heterogeneous EF process were proposed based on the intermediates identified in the degradation of diuron. Toxicity analysis indicated that the heterogeneous EF process could not only degrade diuron but also reduce toxicity. This work presents a novel preparation method of a composite catalyst with excellent catalytic performance in an EF system, which supports the development of efficient heterogeneous EF catalysts.