Development of a Recyclable Remediation System for Gaseous BTEX: Combination of Iron Oxides Nanoparticles Adsorbents and Electrochemistry

Abstract

We designed a two-step green technique to remove and recycle selected gaseous air pollutants. The first step includes the assessment of adsorption efficiencies of BTEX (benzene, toluene, ethylbenzene, and xylenes) on magnetite, hematite, and their composite surfaces. Improvement of the synthesis method led to BTEX adsorption (>85%; 200 ppmv) on 1.0 g of nanoparticles within a time scale of minutes. The second element included the design of an electrochemical reactor for the regeneration of used nanoparticles. NaOH showed superior performance as an electrolyte in comparison to NaCl and Na₂CO₃. The stripping efficiency for cathodic regeneration was higher than the anodic one. Under optimized conditions, the stripping efficiency was up to 85%. Iron oxides nanoparticles were regenerated (∼90%). Using high-resolution transmission electron microscopy, X-ray diffraction, NanoScan, and Brunauer–Emmett–Teller, selected physical and chemical properties of nanosurfaces were analyzed, revealing that the physical properties of nanoparticles remained unchanged during the regeneration process