Sustainable rice husk ash-tannin xerogel for ciprofloxacin removal from water

This research investigates the synthesis and application of a bioderived xerogel (BDX) synthesized from rice husk and tannins to eliminate Ciprofloxacin (CIP) from water-based media. Xerogel was prepared via sol-gel method, incorporating rice husk ash and tannin extract, along with polyvinyl alcohol (PVA) as a binding agent. Characterization techniques including, FTIR (Fourier Transform Infrared Spectroscopy), XRD (X-ray Diffraction), SEM (Scanning Electron Microscopy), AFM (Atomic Force Microscopy), TGA (Thermogravimetric Analysis), and BET (Brunauer-Emmett-Teller) surface area analysis were employed to evaluate its structural and chemical properties. Adsorption capacity of the xerogel was assessed through batch experiments under various conditions of temperature, pH, adsorbent-dosage, and initial-CIP concentration. Results indicate that bio-derived xerogel exhibits promising adsorption properties for CIP, with maximum efficiency observed under acidic conditions and at higher temperatures. The adsorption isotherm and kinetic studies further confirm the applicability of the Langmuir isotherm and pseudo-first-order kinetics model, respectively, suggesting adsorption is mono-layer with physisorption as the rate-limiting step. Moreover, regeneration studies demonstrate the potential for reusability, supporting its practical application for environmental remediation applications.