Electrochemically-driven regeneration of iron (II) enhances Fenton abatement of pesticide cartap

Cartap is a carbamate insecticide intended to protect crops such as rice, tea, and sugarcane. Cartap in the environment presents a serious threat to non-target organisms through direct exposure or via biomagnification. Electro-assisted Fenton technology taps the potential of Fenton reagents to degrade cartap. Electrochemical reduction of iron accelerates catalyst regeneration. Cartap degradation was first investigated by varying reaction pH, as well as the initial H₂O₂ and Fe²⁺ dosage, followed by optimization studies using central composite design. Parametric results indicate the highest cartap removal of 98.10% was achieved at 1.6 pH, 3.0 mM Fe²⁺, and 40 mM H₂O₂ at I = 1.0 A and t = 30 min. These results notoriously surpass conventional Fenton that only achieved 53.8% cartap removal under similar conditions. The hybridization of Fenton process through electrochemical regeneration enhances removal and increases degradation kinetic up to a pseudo-first-order rate constant value of 21.30 × 10^–4 s⁻¹. Effects of coexisting inorganic salts PO₄^3–, NO₃^–, and Cl^– at 1 mM and 10 mM concentrations were investigated. These results demonstrate that Fenton electrification as process intensification alternative can enhance the performance and competitiveness of conventional Fenton by ensuring higher availability of iron catalyst while minimizing sludge production.