Efficient removal of Deltamethrin (pyrethroid ester insecticide) from water using novel chemically activated carbon derived from the inner stem bark of C. Verum tree

Here, we report the adsorptive removal of Deltamethrin (DEL) from wastewater using activated carbon (AC) from the inner stem bark of the C. Verum tree. The raw material was chemically activated using H3PO4, with different impregnation ratios of 1:1, 2:1, and 3:1 (wt%) followed by pyrolysis at 700 °C. Adsorption experiments are carried out to study different effects on the removal of DEL by the prepared AC. The prepared AC has a high surface area between 1009 and 1954 m2/g, total pore volume between 0.47–1.22 mL/g, and a pore diameter around 2 nm. FTIR results revealed the presence of acidic and basic functional groups within the new adsorbent. Kinetic studies showed that adsorption data followed the pseudo-second-order model. Langmuir's model showed a maximum adsorption capacity of 89.3 mg/g at 40 °C. Changes in free energy (∆G°), enthalpy (∆H°), and entropy (∆S°) were also calculated. The thermodynamic characteristics demonstrated that DEL adsorption was a spontaneous endothermic process.