In this work, a functionalized multi-walled carbon nanotubes modified glassy carbon electrode (GCE/MWCNT-f) was optimized for the direct determination of imidacloprid (IMC) insecticide in river water. The functionalized material was characterized by infrared spectroscopy with Fourier transform (FTIR) and the modified electrode by scanning electron microscopy (SEM) and cyclic voltammetry (CV). Results revealed that the GCE/MWCNT-f effectively increased the response toward IMC reduction by enhancing the reduction peak current and decreasing the peak potential in comparison with the bare electrode. After optimizing the electroanalytical conditions, the GCE/MWCNT-f showed a linear voltammetric response at concentration ranging from 2.40 × 10⁻⁷ to 3.50 × 10⁻⁶ mol L⁻¹, with detection and quantification limits of 4.15 × 10⁻⁷ mol L⁻¹ and 1.38 × 10⁻⁶ mol L⁻¹, respectively. The recovery rate of IMC in spiked river water samples varied from 90–95%. Thus, this sensor can be a promising tool for the analysis and monitoring of IMC in complex environmental matrices.

Pesticides are used worldwide in agriculture to prevent insects and other pests that attack plants and their derivatives. Acetamiprid (ACT) is a type of insecticide belonging to the chemical group of neonicotinoids, which are widely used in agricultural planting to replace organophosphates. Therefore, in this work, the performance of the electrochemical oxidation (EO) process as an alternative solution to eliminate pesticides in water was evaluated. A dimensionally stable anode (DSA, TiO₂-RuO₂-IrO₂) and boron-doped diamond (BDD) were tested as anodes for degrading ACT (30 and 300 mg L⁻¹) by using different applied current densities (j): 30, 60, 90, and 120 mA cm⁻². The degradation process was monitored by using ACT decay, spectrophotometric analysis, and chemical oxygen demand. The results clearly showed that ACT (30 mg L⁻¹) was only eliminated from water at the DSA electrode when 90 mA cm⁻² was applied, reaching higher removal efficiencies after 180 min of electrolysis. Conversely, ACT was quickly removed at all applied current densities used, at the same concentration. On the other hand, when the ACT concentration was increased (300 mg L⁻¹), 71.4% of the COD removal was reached by applying 90 mA cm⁻² using BDD, while no significant improvements were achieved at the DSA electrode when a higher concentration of ACT was electrochemically treated.