Visible-light active collagen-TiO2 nanobio-sponge for water remediation: A sustainable approach

Pollution owing to the dye house wastewater and negligent disposal of proteinaceous wastes are major threats to the environment. The conventional water treatment and solid waste management techniques are neither efficient nor cost effective. Here, we developed a collagen-TiO2 nanoparticles based photocatalytic nanobio- sponge from bio-waste for the remediation of organic dyes from wastewater. TiO2 nanoparticles were functionalized (TIF) with 3-aminopropyltriethoxysilane for stabilizing type-I collagen fibers extracted from cowhide wastes. 13C-nuclear magnetic resonance (13C NMR) and Fourier-transform infrared (FT-IR) spectroscopic analyses confirm the amine functionalization on the surface of TiO2 nanoparticles. Thermal stability of collagen fibers is increased to 84 C after treatment with TIF, which is 20 C higher than that of pristine collagen fibers. Further, we converted them into a bio-sponge for photocatalytic degradation of Rhodamine-B (RhB). We demonstrate that the collagen nanobio-sponge loaded with 10% (w/w) TIF nanoparticles can degrade RhB up to 95% under visible light irradiation as well as direct sunlight with a reduction in chemical oxygen demand up to 94%. Photo degradation of RhB was not manifested when the reaction was carried out in dark conditions. The results of this study pave way for the cost-effective and sustainable development of engineered biomass based sponges for real-life environmental remediation applications.