Sustainable CNT–Biopolymer/TiO₂ Bio-nanocomposite Thin Films for Efficient Visible-light-driven Wastewater Remediation
J. Environ. Nanotechnol., Volume 15, No 2 (June 2026) pp. 90-97
Abstract
The photocatalytic degradation process is widely used to effectively remove organic contaminants from wastewater, contributing significantly to environmental protection and ecological sustainability. In this study, a CNT–chitosan/PVA/TiO₂ bio-nanocomposite thin film (CNT–CPT) was prepared using chitosan (CS) and polyvinyl alcohol (PVA) as the matrix for loading TiO₂ nanoparticles via solution casting. Furthermore, blending with carbon nanotubes (CNTs) improved charge-carrier separation and enhanced photocatalytic activity. The novelty of this work lies in the synergistic integration of CNTs within the CS/PVA/TiO₂ matrix to improve charge separation and enable efficient visible-light-driven photocatalysis. The structural and morphological properties of the bio-nanocomposite films were investigated using XRD, FTIR, photoluminescence, and SEM. The photoluminescence properties of CNT–chitosan/PVA/TiO₂ (CNT–CPT) thin-films were compared with those of chitosan/PVA/TiO₂ (CPT) thin films to highlight the role of CNTs in reducing charge recombination. The bio-nanocomposite films were prepared with varying concentrations of CNT–TiO₂ (10 mg, 50 mg, and 100 mg) to optimize performance. The photocatalytic degradation efficiency of the CNT–CPT bio-nanocomposite was evaluated using methylene blue (MB) under visible-light irradiation. It was found that the bio-nanocomposite film prepared with 10 mg of CNT–TiO₂ exhibited the highest photocatalytic degradation efficiency toward MB. It was also observed that CNT–CPT films achieved higher MB degradation efficiency (94.5%) than CPT films (80.3%). The improved photocatalytic performance of CNT–CPT is attributed to reduced charge-carrier recombination resulting from enhanced charge separation facilitated by CNT incorporation.
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