Ultrasound-assisted preparation of Fe(OH)3@bacterial cellulose aerogel for efficient removal of organic contamination in water

As an abundant and renewable polymer, bacterial cellulose-based aerogel (BCA) loading with Fe(OH)3 nanoparticles was successfully prepared by ultrasound-assisted treatment and exhibited excellent adsorption efficiency for dye removal from polluted water. Wastewater containing toxic synthetic dyes is causing serious damage to the ecological environment and human health, and more attention has been paid to the nanoscale materials for water purification because of their unique structure and large specific surface area. With the help of ultrasonic waves, iron and hydroxide ions could fully penetrate the complex network of cellulose aerogel and generate the uniformed Fe(OH)3 particles, homogeneously being located all over the adsorbent. The physical adsorption from the multi-scaled pore structure in cellulosic aerogel and the chemical formation of electrostatic interaction and the hydrogen bonds between Fe(OH)3 and Congo red (CR) synergistically acted and significantly improved the absorbability. Finally, the maximum adsorption capacity of CR was achieved to 335 mg/g at natural conditions, which was higher than many reported values. The kinetics of the adsorption under different temperatures, pH, and time were comparatively measured, and the physical and structural characteristics were also investigated in detail using XPS, SEM, EDS, XRD, etc., technologies. Importantly, this approach is expected to provide a simple and operable process for fabricating cellulose-based aerogel and broadening the fields of applications.