Bi12O17Cl2/(BiO)2CO3 Nanocomposite Materials for Pollutant Adsorptionand Degradation: Modulation of the Functional Properties by CompositionTailoring

摘要

Bi12O17Cl2/(BiO)2CO3 nanocomposite materials were studied as bifunctional systems for depuration of wastewater. They are able to efficiently adsorb and decompose rhodamine B (RhB) and methyl orange (MO), used as model pollutants. Bi12O17Cl2/(BiO)2CO3 nanocomposites were synthesized at room temperature and ambient pressure by means of controlled hydrolysis of BiCl3 in the presence of a surfactant (Brij 76). Cold treatments of the pristine samples with UV light or thermal annealing at different temperatures (370–500 °C) and atmospheres (air, Ar/30% O2) were adopted to modulate the relative amounts of Bi12O17Cl2/(BiO)2CO₃ and hence the morphology, surface area, ζ-potential, optical absorption in the visible range, and the adsorption/degradation of pollutants. The best performance was achieved by (BiO)₂CO₃-rich samples, which adsorbed 80% of MO and decomposed the remaining 20% by visible light photocatalysis. Irrespective of the dye, all of the samples were able to almost complete the adsorption step within 10 min contact time. Bi₁₂O₁₇Cl₂-rich composite materialsdisplayed a lower adsorption ability, but thanks to the stronger absorptionin the visible range they behaved as more effective photocatalysts.The obtained results evidenced the ability of the employed strategyto modulate sample properties in a wide range, thus pointing out theeffectiveness of this approach for the synthesis of multifunctionalinorganic materials for environmental remediation.