Fabrication and Characterization of Gelatin-Chitosan-TiO2 Hybrid Nanobiocomposite Films for Adsorptive Removal of Dyes from Wastewater

Abstract

Wastewater generated from the process of dyeing is often inadequately treated and discharged into natural waterways. This may alter the ecology by reducing water clarity and sun radiation penetration, thereby affecting the photosynthesis process. Adsorption is an efficient and simple method for removing harmful dyes from water, offering outstanding performance and minimal operating expenses. The strategy of designing adsorbents with high separation efficiency using biodegradable polymer-based nanocomposite is an attractive option. Solution casting methods were followed to synthesize gelatin-chitosan biocomposite in three different ratios (1:1, 1:2 and 2:1). To enhance the efficiency of dye adsorption, titanium dioxide nanoparticles have been incorporated in various weight percentages (1, 2 and 5% w/w) to the chosen gelatin-chitosan composite. Several analytical techniques including XRD, FESEM, FTIR, DLS, contact angle and UV-Vis spectroscopy were used to characterize the prepared samples. The adsorption capacities of the nanobiocomposite films were determined using 6-nitro amino phenol sulphonic acid as reference dye at different time intervals and analyzed using UVVis spectroscopy and the results suggest that the nanobiocomposite with 5% loading of titanium dioxide nanoparticles led to faster adsorption of the dye. The adsorption kinetics and isotherm models were investigated and various parameters including maximum adsorption capacity were also derived. A practical application of the developed nanocomposite was established for the removal of brown dyes from the post-tanning wastewater. Therefore, the study shows potential for the fabricated films for applications in organic dye removal from wastewater