Nanocarbon-based aerogel filters for water separation
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Date
2026-07-07
Authors
Πεκίνι, Εστέλα
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Abstract
Environmental degradation caused by water contamination from persistent organic pollutants has intensified the need for advanced wastewater treatment technologies. Synthetic dyes and emerging pharmaceutical contaminants threaten aquatic ecosystems and human health, as they often bypass conventional treatment facilities. Among cutting-edge functional nanomaterials, three-dimensional (3D) graphene-based macrostructures, particularly reduced graphene oxide (rGO) aerogels, are ex cellent candidates for water purification due to their exceptional porosity, low density, and high ac cessible surface area.This thesis focuses on the development of structurally intact rGO aerogels, the evaluation of their formulation parameters, the subsequent optimization of the precursor graphene oxide (GO) soni cation pre-treatment, and their assessment as efficient adsorbents for the removal of diverse organic contaminants. This research was conducted at the Laboratory of Nanotechnology and Advanced Ma terials of the Institute of Chemical Engineering Sciences (FORTH/ICE-HT) in Patras.The experimental framework began with the development of a baseline synthesis protocol. Pre liminary batch adsorption experiments were conducted using Methyl Orange (MO) as a model anionic dye to systematically screen both the effect of the aerogel formulation concentration (at a constant MO concentration) and the effect of the initial MO solution concentration (using a fixed aerogel mass). These initial tests revealed that an aerogel concentration of 4 mg/mL provided the optimum balance between structural stability and adsorption performance. Based on these findings, the soni cation treatment parameters of the precursor dispersion were systematically varied to further regu late the exfoliation state and lattice stability of the sheets. This approach successfully generated light weight monoliths with enhanced structural integrity, exceptional volume stability, and low bulk den sities (7-12 mg/cm3). The structural, chemical, and morphological evolution of the precursors and final 3D porous networks was verified using Optical Microscopy, Scanning Electron Microscopy (SEM), and Raman Spectroscopy.To further evaluate the operational capacity and versatility of the fully optimized adsorbents, time-resolved batch adsorption experiments utilizing UV-Visible spectroscopy were carried out across additional model pollutants including Methylene Blue (cationic dye), Carmine (complex natural dye), and Enrofloxacin (emerging pharmaceutical antibiotic contaminant). The effects of critical op erational parameters, including adsorbent dosage, solution volume (scalability), and initial contami nant concentration, were thoroughly quantified. Furthermore, the structural stability and sustaina bility of the aerogels were demonstrated through multi-cycle reusability and regeneration tests, de termining the practical limits of the material's performance over consecutive reuse.In conclusion, this investigation establishes that the initial screening of aerogel concentration combined with precise control over the sonication pre-treatment of GO precursors dictates the ar chitectural quality and volumetric stability of the resulting 3D networks. The synthesized rGO aero gels function as effective, structurally stable, and regenerable adsorbents, offering a scalable tech nological platform for advanced water purification applications.
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Keywords
Aerogels, Water treatment, Reduced graphene oxide, Adsorption, Organic pollutants, Dyes removal, Antibiotic removal, Scalability study, Reusability studies