Highly stable carbon-coated nZVI composite Fe ⁰@RF-C for efficient degradation of emerging contaminants

Abstract

Nanoscale zerovalent iron (nZVI) has garnered significant attention as an efficient advanced oxidation activator, but its practical application is hindered by aggregation and oxidation. Coating nZVI with carbon can effectively addresses these issues. A simple and scalable production method for carbon-coated nZVI composite is highly desirable. The anti-oxidation and catalytic performance of carbon-coated nZVI composite merit in-depth research. In this study, a highly stable carbon-coated core-shell nZVI composite (Fe ⁰@RF-C) was successfully prepared using a simple method combining phenolic resin embedding and carbothermal reduction. Fe ⁰@RF-C was employed as a heterogeneous persulfate (PS) activator for degrading 2,4-dihydroxybenzophenone (BP-1), an emerging contaminant. Compared to commercial nZVI, Fe ⁰@RF-C exhibited superior PS activation performance and oxidation resistance. Nearly 95% of BP-1 was removed within 10 min in the Fe ⁰@RF-C/PS system. The carbon layer promotes the enrichment of BP-1 and accelerates its degradation through singlet oxygen oxidation and direct electron transfer processes. This study provides a straightforward approach for designing highly stable carbon-coated nZVI composite and elucidates the enhanced catalytic performance mechanism by carbon layers.

Graphical abstract

Highlights

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  A simple and scalable method is developed for preparing a carbon-coated nZVI composite.

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  Fe ⁰@RF-C shows significantly higher oxidation resistance than commercial nZVI.

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  The Fe ⁰@RF-C/PS system removes 94.9% of BP-1 within 10 min.

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  The crucial role of the carbon layer in enhancing BP-1 degradation is elucidated.