Persulfate Activation by Encapsulated Sulfidated Nanoscale Zerovalent Iron for 2,4-Dichlorophenol Removal

Herein, a catalyst was synthesized using sodium alginate (SA), poly(vinyl alcohol) (PVA), and sulfidated nanoscale zerovalent iron (SNZVI), referred to as SA/PVA@SNZVI, to activate persulfate (PDS) for the degradation of 2,4-dichlorophenol (2,4-DCP). To assess the performance of SA/PVA@SNZVI, we investigated various influencing parameters, such as the PDS concentration, SA/PVA@SNZVI dosage, initial pH, initial concentration of 2,4-DCP, reaction temperature, and coexisting ions in the system. The results from batch experiments and repeated use trials indicate that SA/PVA@SNZVI exhibited excellent catalytic activation capability, making it a promising choice for 2,4-DCP removal. It achieved 100% 2,4-DCP removal within 40 min with low PDS consumption. Additionally, electron paramagnetic resonance analysis and quenching experiments confirmed SO₄^·- and ·OH as the primary active substances during 2,4-DCP degradation, with ·OH playing a predominant role. The degradation pathway of 2,4-DCP comprised dechlorination, ·OH addition, and dehydrogenation processes. The SA/PVA@SNZVI/PDS system reduced the toxicity of 2,4-DCP. These findings indicate that employing sustained-release Fe²⁺ to activate PDS may effectively degrade 2,4-DCP in water.