Application of Carbon Materials Derived from Nocino Walnut Liqueur Pomace Residue for Chlorpyrifos Removal from Water

Abstract

This study explores the use of carbon materials derived from Nocino walnut liqueur pomace residue for the removal of chlorpyrifos, a widely used organophosphate pesticide, from water. Carbon adsorbents were synthesized from young walnut biomass under different thermal and chemical treatment conditions, and their structural and surface properties were characterized using BET analysis, FTIR, SEM-EDX, Boehm titration, and zeta potential measurements. The materials exhibited distinct textural and chemical features, including high surface areas and varied surface functionalizations. Batch adsorption studies revealed that the chlorpyrifos removal followed pseudo-second-order kinetics and was best described by the Freundlich and Langmuir isotherms, indicating a combination of pore filling and physisorption via π-π and van der Waals interactions. The highest adsorption capacity of 45.2 ± 0.2 mg g-1 was achieved at 30 °C. Thermodynamic analysis confirmed the process to be endothermic, spontaneous, and entropy-driven, with desolvation effects enhancing the performance at elevated temperatures. Dynamic filtration experiments validated the practical applicability of the materials, while moderate reusability was achieved through ethanol-based regeneration. These findings demonstrate the potential of walnut pomace-derived carbons as low-cost, renewable, and effective adsorbents for sustainable water decontamination.