Green Preparation of Flexible and Transparent SiO2-Fe2O3-PS film for Dye Adsorption and UV-Shielding Applications

Abstract

A multifunctional green polymer nanocomposite (SiO2-Fe2O3-PS) film has been prepared using earth-abandoned and waste materials such as natural sand, waste expanded polystyrene (EPS), and pea eggplant fruit extract. SiO2 was prepared using natural sand by alkali fusion method, SiO2-Fe2O3 was prepared by microwave assisted green synthesis method and the SiO2-Fe2O3-PS film was prepared by solution casting method. The SiO2-Fe2O3 (20:80)-PS film shows the shielding efficiency of 91–100% in the wavelength range of 390 − 200 nm and transparency of 71% to visible light at 800 nm. The SiO2-Fe2O3 (50:50)-PS film shows maximum adsorption capacity of 61.2% to methylene blue (MB) dye. The UV-Vis peak position of SiO2 (326 nm) and Fe2O3 (276 nm) are in line with the literature. The peak position in SiO2-Fe2O3 at different wt% ratio, were found at 290 nm (10:90), 328 nm (20:80), and 292 nm (50:50), which are indicative of the formation of heterostructure. The XRD data of SiO2-Fe2O3 comprises sharp peaks of both components that confirm the heterostructure formation and its crystalline nature. The SiO2-Fe2O3-PS composite formation was confirmed by FTIR and FESEM. The film is hydrophilic in nature (contact angle of 75.96°) and shows maximum thermal stability upto 381.6 ℃ (SiO2-Fe2O3 (20:80)-PS). The adsorption experiment was carried out using a 50 mg catalyst either in powder or film form with 100 mL dye solution of concentration 20 mg/L, where equilibrium adsorption was achieved within 180 minutes. The adsorption efficiency of SiO2, Fe2O3, SiO2-Fe2O3 (20:80), SiO2-Fe2O3(50:50), and SiO2-Fe2O3(50:50)-PS are found to be 98.3%, 3.88%, 91.1%, 96.2%, and 61.2%, respectively. The MB dye adsorption process follows pseudo second order kinetics and is best fitted with the Langmuir isotherm model. The novel SiO2-Fe2O3-PS film is found to be low cost, green, and environmentally friendly with multifunctional applications in the area of UV shielding, visible transparent and dye adsorption.