Fe3+ and H2O2 assisted dopamine rapid polymerization on melamine foam to activate PMS for organic pollutant degradation†

Developing a facile preparation method to construct separable and recyclable Fenton-like catalysts holds great significance in the field of environmental remediation. Herein, a rapid dopamine (DA) polymerization strategy to modify melamine foam (MF) was proposed for the construction of bulk foam catalytic materials, which was further utilized for peroxymonosulfate (PMS) activation to degrade organic pollutants. Taking advantage of the chelation between dopamine's catechol group and Fe³⁺, as well as the oxidative environment provided by H₂O₂, DA could encapsulate and polymerize on the surface of MF within 2 h to obtain the MF@Fe@PDA catalyst. Detailed experimental results demonstrated that MF@Fe@PDA could efficiently activate PMS to achieve almost 100% removal of bisphenol A (BPA) in 20 min, and the corresponding turnover frequency (TOF) value was one order of magnitude higher than that of the homogeneous (Fe²⁺, Fe³⁺) and nanoparticle (Fe⁰) catalysts. The high activity of the MF@Fe@PDA/PMS system stemmed from the Fe sites and carbonyl group (CO), which could induce the activation of PMS for the rapid generation of singlet oxygen (¹O₂), sulfate radical (SO₄˙⁻) and hydroxyl radicals (˙OH). Meanwhile, the coexisting bicarbonate ions (HCO₃⁻) in the MF@Fe@PDA/PMS system could enhance the generation of ¹O₂, thereby accelerating the degradation of BPA. Moreover, a flow-through system assisted by the bulk MF@Fe@PDA catalyst was constructed for organic pollutant degradation. Overall, these findings may open up new possibilities for developing highly efficient catalysts for wastewater remediation.