Controllable conversion of Prussian blue@yeast bio-template into 3D cage-like magnetic Fe3O4@N-doped carbon absorbent and its cohesive regeneration by persulfate activation

Abstract

A multitude of heteroatom-doped carbon adsorbents have been explored to cope with ever-growing organic pollution. However, development of these advanced carbon materials with adequate activity and stability remains challenging. Herein, unique 3D cage-like magnetic N-doped Fe₃O₄@C adsorbents were rationally constructed by a one-step pyrolysis of Prussian blue@yeast (PB@yeast) bio-templates. By using yeast as an available biological support, the prepared Fe₃O₄@C hybrids were demonstrated to provide a sufficient number of Fe, N and C atoms for the novel cage-like microstructures, making them a new type of Fe, N co-doped carbon absorbents with a facile preparation procedure and remarkable adsorption behavior. Rhodamine B (RhB) removal indicated that the prepared N-doped Fe₃O₄@C adsorbents displayed high adsorption capabilities in a near-neutral solution, and Fe₃O₄@C (1 : 0.11) exhibited a maximum adsorption capability of 257.06 mg g⁻¹. More importantly, spent N-doped Fe₃O₄@C absorbents, which could be recovered by magnetic separation and cohesive persulfate (PS) activated photo-Fenton regeneration, showed excellent adsorption reusability and high stability even after 5 cycles. Overall, this paper presents a simple method for fabrication of a 3D cage-like magnetic N-doped Fe₃O₄@C adsorbent, which provides a significant guidance for the study of Fe, N co-doped carbon adsorbents towards dye wastewater treatment.