Removal of carbofuran from aqueous solutions using activated carbon derived from Pistacia khinjuk stocks (bıttım) shell waste

Abstract Pesticides are important environmental pollutants that require effective removal to protect ecosystems and human health. This study investigated carbofuran removal from water using KOH-activated carbon derived from Pistacia khinjuk Stocks (bıttım) shell waste. The resulting adsorbent exhibited a high specific surface area (1552 m² g⁻¹). Under the selected conditions (50 mg L⁻¹ carbofuran, 0.01 g adsorbent, 0.25 L solution, pH 4.0, 25 min, and 298 K), the highest experimental adsorption capacity was 324.3 mg g⁻¹. In synthetic water, the adsorption capacity was 276.5 mg g⁻¹, retaining approximately 85.3% of that obtained in ultrapure water. The apparent thermodynamic parameters and the decrease in adsorption capacity with increasing temperature were consistent with favorable adsorption and an exothermic temperature dependence under the investigated conditions. The Langmuir isotherm best described the equilibrium data. Adsorption appeared to involve hydrophobic and π–π electron donor–acceptor interactions, while electrostatic attraction likely played a limited role. These findings demonstrate the potential of bıttım shell-derived activated carbon as a biomass-derived adsorbent for carbofuran removal from water.