Use of a 416B-type central-hybrid experimental design to evaluate the synthesis conditions of TiO2/biochar composites on the solid-state photocatalytic degradation of polypropylene-plastic films

This study presents an innovative application of solid-state photocatalysis using environmentally friendly TiO 2 /biochar composites to degrade polypropylene (PP) films and reduce plastic pollution. Biochar, derived from coconut shells via controlled pyrolysis, was combined with TiO 2 to enhance photocatalytic activity. A 416B-type Central-Hybrid Experimental Design was used to optimize synthesis parameters, revealing that biochar produced at 280°C with 4.1% v/v oxygen and a TiO 2 /biochar weight ratio of 1.5 yields the best results. After 25 days of UV irradiation, films incorporated with TiO 2 /biochar composites exhibited an 8.7% weight loss and a carbonyl index of 11.4—significantly surpassing pristine PP films. These findings demonstrate the potential of biochar as a sustainable solution to reduce nanotoxicity while boosting polymer degradation efficiency. This work contributes to the development of eco-friendly materials for mitigating plastic waste challenges. • Outstanding degradation of PP (plastic) based films (8.7% of weight loss in only 25 days) with solid-state photocatalysis. • Synthesis of novel photodegradable films using biowaste (coconut shells) derived products. • Optimization of plastic-film photodegradation with a 416B-type Central-Hybrid Experimental Design. • Biochar support is expected to prevent the nanotoxicity of TiO 2 particles.