Bacterial Cellulose/Polypyrrole Aerogel for the Efficient Removal of Organic and Inorganic Water Contaminants

In this work, in situ oxidative polymerization of pyrrole in the presence of bacterial cellulose (BC) hydrogels was utilized to prepare BC/polypyrrole (PPy) aerogels. Various analytical techniques, such as scanning electron microscopy with energy-dispersive X-ray spectroscopy, thermal gravimetric analysis, Fourier transform infrared (FTIR) and Raman spectroscopies, and BET specific surface area analysis, were employed to characterize the BC/PPy composite. Raman and FTIR spectroscopy confirmed the formation of doped PPy that uniformly coated the BC fibers. BC/PPy has demonstrated excellent adsorption capability of organic (Reactive Black 5, RB) and inorganic (hexavalent chromium ions, Cr-(VI)) wastewater contaminants in single and binary solute systems. Various parameters, e.g., contact time, pH, and adsorbent dosage, were evaluated in batch sorption experiments. The adsorption processes were found to obey pseudo-second-order kinetics and Langmuir isotherm models. Vibrational spectroscopy indicates that the Cr-(VI) adsorption involves redox reactions, while RB adsorption occurs through ion exchange. The maximum adsorption capacity of 485.4 and 130.7 mg g^-1 of Cr-(VI) and RB was achieved at pH 2 and 4, respectively. After five adsorption/desorption cycles, BC/PPy maintained removal efficiencies of 92.1 and 97.7% for Cr-(VI) and RB, respectively. This research demonstrates the cost-effectiveness, reusability, and sustainability of BC/PPy as an adsorbent for removing pollutants from wastewater.