Innovative low-voltage 3D electrode system using pine cone biochar for efficient removal of multicomponent pollutants from wastewater

The removal of pharmaceuticals in multicomponent systems, in contrast to conventional studies focused on single pollutants, represents a significant challenge in advance in wastewater treatment. This study proposes the integration of a pine cone-derived adsorbent (BPC) into a three-dimensional (3D) electrosorption system for concurrent removal of pharmaceuticals, exploring compounds interactions in complex mixtures. Firstly, the physicochemical properties of BPC revealed high porosity and functional groups that facilitate adsorption. Batch adsorption assays identified the optimal conditions: a particle size of <0.25 mm and a BPC dose of 2.5 g/L, achieving 100 % removal of fluoxetine (FLX) and promising results for sulfamethoxazole (SMX) and sulfamethizole (SMZ). Then, the 3D electrosorption system, operating at 1.2 V, enhanced adsorption capacity for SMX and SMZ, which increased by 1.67 and 1.69 times, respectively, after three cycles of use. Further testing in a continuous flow configuration with a multicomponent matrix showed a 1.13-fold, 1.60-fold and 1.34-fold improvement for the FLX, SMZ and SMX adsorption capacity in 3D electrosorption compared to continuous flow adsorption. Multicomponent isotherm modelling, using Sheindorf-Rebuhn-Sheintuch (SRS) model, accurately described pollutant interactions. Desorption and regeneration processes were analyzed using organic solvents, showing partial in situ degradation of pollutants. Finally, 3D electrosorption treatment was applied to river water to evaluate its practical feasibility. The results highlight the potential of BPC when integrated with a 3D electrosorption system as a sustainable and cost-effective solution for wastewater treatment containing multicomponent pollutants, supporting the Sustainable Development Goals and aligning with circular economy principles. • Removal of FLX, SMX and SMZ by pyrolysis-derived BPC was evaluated. • Mechanisms were hydrogen bonds, hydrophobic, electrostatic and π-π interactions. • 3D electrosorption improved pollutant removal by 60 % after three uses. • BPC showed removal capacity in single-component and multicomponent systems. • Multicomponent isotherm model showed competitiveness for active sites with FLX.