Use of cassava waste nanofibrils for adsorption of selected second-line Art Drugs: Atazanavir and Tenofovir

Author

Makaza, Lovemore C.

Title

Use of cassava waste nanofibrils for adsorption of selected second-line Art Drugs: Atazanavir and Tenofovir

Abstract

Utilizing agricultural waste into low cost-effective adsorbents presents a sustainable solution to the growing challenge of pharmaceutical water contamination. In this current study, nanocellulose and lignin-containing cellulose nanofibrils were synthesized from cassava waste using alkali treatment followed by partial bleaching process and mechanical homogenization. Lignin containing cellulose nanofibrils were used as the adsorbent after being characterized using Fourier-Transform Infrared spectroscopy, X-ray Diffraction, Thermogravimetric Analysis, and Scanning Electron Microscopy with Energy-Dispersive X-ray Spectroscopy followed by the evaluation for the effective adsorption of the selected second-line antiretroviral drugs, Atazanavir and Tenofovir. Fourier-Transform Infrared analysis confirmed the successful biosorption of Atazanavir and Tenofovir, revealing prominent shifts in the amide and aromatic regions (1650-1500 cm⁻¹) on the drug-loaded adsorbent. X-ray diffraction analysis showed a stable pattern even after adsorption proving that the adsorbent is structurally robust, confirming that adsorption occurs on the surface without damaging the material's core, which is essential for its durability. Thermogravimetric analysis confirmed the thermal stability of the adsorbent, and significantly, the Lignin-containing cellulose nanofibrils demonstrated superior purity with a final ash content below 1%, compared to the raw peel. Scanning electron micrographs revealed a highly porous, layered microstructure that became visibly smoother after sorption, while Energy-Dispersive X-ray spectroscopy confirmed the adsorbent is primarily composed of carbon (54.5 Wt%) and oxygen (45.3 Wt%). The data modelling followed the pseudo-second-order kinetics, indicating chemisorption was the rate limiting step in the adsorption process. The adsorption process for both drugs fitted the Freundlich isotherm model suggesting adsorption on a heterogeneous surface. Thermodynamic analysis confirmed the process is endothermic, spontaneous, and entropy-driven. Future work should focus on competitive adsorption studies and put attention to regeneration studies.

Date

June 2025

Publisher

BUSE

Keywords

Nanofibrils

Cassava Waste

Second-line Art Drugs

Atazanavir and Tenofovir

Supervisor

Dr. N. Muchanyereyi