Synthesis, characterization and investigation of the usage as an adsorbent of lignin/polythiophene (Li/PTh) composite

In this study, Lignin/Polythiophene (Li/PTh) composite was used for the first time for the removal of carbaryl, a carbamate pesticide, from water. The structural properties of the synthesized Li/PTh composite were investigated using Fourier Transform Infrared Spectroscopy (FTIR) and X-Ray Diffraction (XRD studies. Its morphological properties were examined by Scanning Electron Microscopy (SEM), while the removal studies of carbaryl pesticide in water were conducted using Ultraviolet and Visible Absorption Spectrometry (UV-Vis). Some experimental conditions for the adsorption of carbaryl by the composite were optimized. The optimum adsorption conditions were determined as 5 mg of adsorbent, pH 7, an initial carbaryl concentration of 1 mg/L, a stirring speed of 200 rpm, and a contact time of 15 minutes. Following the determination of optimum conditions, the removal studies of carbaryl pesticide in tap water were monitored using High-Performance Liquid Chromatography (HPLC) and UV-Vis instruments. FTIR spectra supporting the formation of the synthesized Li/PTh composites were obtained. SEM results showed that the morphology of lignin changed upon coating with polythiophene. Conductivity results indicated that the conductivity value of the formed composite (5.75x10⁻⁸ S/cm) was very low. Under optimum conditions, HPLC results obtained from tap water treated with the Li/PTh composite demonstrated that the composite can be used for carbaryl removal. The developed method showed an 88% removal percentage for carbaryl-spiked tap water, while the HPLC method exhibited a 78% recovery value. The Langmuir and Freundlich models are subjected to adsorption datas. The datas fitted better when by using Langmuir model.