Simulated study on electrochemical regeneration of ammonium persulfate for naphthalene degradation in soil

Persulfate-based advanced oxidation processes (PS-AOPs) have emerged as a highly promising approach for remediating organic-contaminated soil. However, the substantial cost associated with the large injection volume of persulfate and the potential ecological risks arising from sulfate accumulation in the post-remediated soil have hindered the widespread application of this technology. To address these challenges, this study proposed a novel and environmental-friendly approach based on the reversible regeneration of ammonium persulfate (APS) through electrochemical synthesis, with the aim of realizing cyclic utilization of APS. Through our in-depth investigation, we have scrutinized the performance and kinetic behaviors of Fe²⁺-APS in the remediation of organic-contaminated soil, utilizing NAP as the target. By identifying the decisive factors for electrochemical regeneration of APS, we have also unraveled the underlying mechanisms governing the electrochemical synthesis of APS. Experimental results demonstrate an impressive degradation rate of 76.39% of naphthalene (NAP) in contaminated soil through Fe²⁺-APS remediation with the optimal parameter (voltage of 8 V, flow velocity of 10 mL/min, ammonium sulfate concentration of 3 M). Moreover, our dynamic electrochemical devices significantly outperform the static setup in terms of regeneration of APS, with the concentration and current efficiency achieving 75 and 20 times higher, respectively. Notably, the NAP degradation rate in the soil remains at a commendable 75% even after five cycles, thereby validating the practicality and efficacy of this approach. This innovative approach provides both theoretical and practical foundations to advance the development and adoption of persulfate-based technologies in soil remediation efforts.