Degradation of Tenofovir Disoproxil Fumarate by a photocatalytic process in combination with aerobic biological treatment using a synthesized bio-nanocomposite (Biomass-TiO): characterization, optimization, mechanism, and DFT calculations.

This study aims to integrate a biological treatment with a photocatalytic treatment for the decontamination of water polluted by a pharmaceutical product called Tenofovir Disoproxil Fumarate using a bio-nanocomposite synthesized from biomass that is an agricultural waste called corn cobs. The biomass-TiO bio-nanocomposite (Bio-TiO) was synthesized using a facile method by mixing TiO with corncobs, then characterized by several techniques including UV-Vis-RDS, SEM-EDS, FT-IR, and XRD for the understanding of its properties. The efficiency of TDF mineralization by the 6-Bio-TiO bio-nanocomposite was evaluated using the BBD (Box-Behnken design); optimum values for TDF degradation and mineralization were found at pH = 4, m = 3 g L and C = 0.1 mM. A degradation rate of over 97% was achieved in 90 min and almost complete degradation after 270 min, as well as a mineralization rate of 99.15% in 360 min. The degradation mechanism was also proposed. The evaluation of biodegradability was verified by the BOD/COD ratio whose value after 2 h of photocatalytic pre-treatment became 0.44, proving that the solution was considered biodegradable. Next, an independent 21-day biological treatment at 25 °C was implemented with a sludge quantity of 1 g L. This process achieved a remarkable mineralization yield of 99.15% on day 17. Three-cycle reuse of 6-Bio-TiO was carried out to confirm its high efficiency and stability after different uses, maintaining a degradation percentage of over 90%. DFT calculations proved effective in accurately predicting the degradation mechanism of the TDF molecule, using Fukui indices as a valuable tool in this process. This study highlights the promising potential of integrating these two processes as an advanced technology.