Abstract:
Water contaminated by pesticides is a serious environmental problem, especially in agricultural areas. A common pyrethroid insecticide that poses serious health and environmental hazards is lambda-cyhalothrin (LC), which is regularly found in contaminated water sources. Activated carbon made from the invasive weed Parthenium hysterophorus was used in this work to assess the adsorption performance of LC from water. Pyrolysis at 500°C yielded carbon, which was then chemically activated with KOH. For the characterization of activated carbon Fourier transform infrared spectroscopy (FTIR), energy dispersive spectroscopy (EDS), and scanning electron microscopy (SEM) were used. Batch adsorption studies were performed to determine the optimal conditions for LC removal. Using UV-Vis Spectrophotometry, the final concentration of lambda-cyhalothrin in the solution after the batch sorption studies was evaluated. The original lambda-cyhalothrin concentration was 100% in the reference sample. The LC removal efficiency of 94% was attained at an initial LC concentration of 50 mg/L, 92% at a contact time of 120 minutes, 93% at an adsorbent dose of 2 g/100 mL, and 93% at pH 6. Adsorption isotherms were assessed using Langmuir and Freundlich models. The experimental data was best fitted by the Freundlich isotherm model, which predicts a heterogeneous surface with varying adsorption intensities and has an R2 value of 0.9952. Adsorption kinetics were more accurately described by the pseudo-secondorder model, which holds that the rate of adsorption is proportional to the square of the number of accessible adsorption sites occupied by the adsorbate. This research demonstrates the dual benefits of using Parthenium Hysterophorus for water treatment: mitigating the spread of an invasive species while providing a sustainable, low-cost solution for pesticide-contaminated water. The results of this study lay the foundation for future research on this adsorbent in environmental remediation application
