The Impact of Titanium Nanotubes (TNTs) Incorporated into a Sodium Alginate-Based Nanocomposite Membrane on the Adsorption of Cationic Dye from Aqueous Solutions

Abstract

In this study, we synthesized a composite membrane of molecularly imprinted TiO2 nanotubes (TNTs) embedded in a Sodium Alginate (SA) supporting matrix. The TNTs were synthesized using a simple hydrothermal technique, resulting in an average length of 20 nm. To improve their recyclability and photoactivity, these nanotubes were immobilized within the SA membrane. The casting solution was applied onto a glass plate using a glass rod to control the film thickness. Subsequently, the TNTs/SA nanocomposite membrane was obtained by drying at room temperature and crosslinking with glutaraldehyde and HCl to improve mechanical strength, chemical resistance and stability of the membrane. The as-prepared TNTs and composite films were characterized using various methods, including X-ray diffraction (XRD), Dynamic light scattering (DLS), Scanning electron microscopy (SEM), and Transmission electron spectroscopy (TEM). Scanning electron microscopy revealed the porous nature of the prepared TNTs/SA composite membrane. Further, these composite membranes were utilized for the adsorption of the cationic dye methylene blue (MB) from aqueous solutions. A 50 mg TNTs/SA nanocomposite membrane achieved an approximate degradation ratio of 85% for a 10 ppm MB concentration under room conditions within 180 min. Additionally, the effects of adsorbent dosage, dye concentration, and temperature were also investigated.