Eco-friendly clay reinforced chitosan and polyethylene glycol based nanocomposites for targeted dye removal in...

The solvent casting technique was applied to synthesize silane crosslinked, sepiolite reinforced chitosan/polyethene glycol novel nanocomposites. Scanning Electron Microscopy (SEM) shows high compatibility between sepiolite and polymer matrix. The particle size of sepiolite, ranging between 90 and 100 nm, confirms the formation of nanocomposites. Energy Dispersive X-ray (EDX) shows the purity of mixing components. However, Fourier-Transform Infrared Spectroscopy (FTIR) results illustrate the Si-O-Si stretching band at 1070 cm^-1 confirms the crosslinking reaction. X-ray Diffraction (XRD) analysis shows the characteristic peak of sepiolite at 7.1°, confirming its fibrous structure. The prepared formulations exhibited optimum swelling behaviours at pH 2. The synthesized biopolymer films were employed for methyl orange adsorption from wastewater. The adsorption studies were conducted using the batch method, and the adsorption of methyl orange was carried out under optimum pH, temperature, time, dosage, and concentration. At pH 2, using 0.025 g of silane-crosslinked nanocomposite, the adsorption of methyl orange is highly effective, achieving 99 % adsorption of the dye from an 80-ppm solution within 4 h at 35 °C. The Langmuir model shows a 0.99 R² value, confirming the monolayer adsorption between adsorbent and adsorbate. The desorption experiment displays a minor desorption efficiency as confirmed by the pseudo-second model, which refers to chemisorption between dye and biopolymer film.