Abstract
In this paper, inorganic silica microspheres with interconnected macroporosity are tested as a platform for designing robust and efficient photocatalytic systems for a continuous flow reactor, enabling a low cost and straightforward purification of wastewater through solar‐driven photocatalysis. The photocatalytically active microspheres are prepared by wet impregnation of porous silica scaffolds with Trizma‐functionalized anatase titania (TiO2) nanoparticles (NPs). NPs loading of 22 wt% is obtained in the form of a thin and well‐attached layer, covering the external surface of the microspheres as well as the internal surface of the pores. The TiO2 loading leads to an increase of the specific surface area by 26%, without impacting the typically interconnected macroporosity (≈60%) of the microspheres, which is essential for an efficient flow of the pollutant solution during the photocatalytic tests. These are carried out in a liquid medium for the decomposition of methyl orange and paracetamol. In addition to photocatalytic activity under continuous flow, the microspheres offer the advantage that they can be easily removed from the reaction medium, which is an appealing aspect for industrial applications. In this work, the typical issues of TiO2 NPs photocatalysts are circumvented, without the need for elaborate chemistries, and for low availability and expensive raw materials.
Highlights
TiO2 is one of the most commonly used photocatalysts due to its advantages of high stability, non-toxicity, low cost, and well-controlled, straightforward synthesis procedure.Removing organic pollutants from wastewater is a critical need it displays a relatively large bandgap, which makes it and a challenge as well
This paper reports the development of photocatalytic microspheres through the immobilization of Trizma functionalized TiO2 NPs within SiO2 microscaffold of spherical shape (MSs) with interconnected macroporosity, which will be assessed for the degradation of methyl orange (MO) and paracetamol, under simulated solar illumination
The present paper reports the achievement of an efficient, lowcost, and straightforward engineered photocatalytic system, driven by solar light, of high applicability in a real-life scenario, targeting wastewater purification, that is, the degradation of organic pollutants
Summary
TiO2 is one of the most commonly used photocatalysts due to its advantages of high stability, non-toxicity, low cost, and well-controlled, straightforward synthesis procedure. The use of metal oxide NPs for heterogeneous photocatalytic decomposition of various pollutants in liquid-phase has been employed and successfully demonstrated, but has some drawbacks because the NPs are dispersed in the liquid media that they treat: a) contamination with NPs and need for sophisticated removal strategies; b) no possibility for continuous flow-through operation, so that only small volumes of wastewater can be treated in a discontinuous (batch) way; and c) tendency to rapidly aggregate in a suspension, due to their relatively small size, considerably decreasing their effective surface area and catalytic efficiency These disadvantages pull this technology away from practical application. This paper reports the development of photocatalytic microspheres through the immobilization of Trizma functionalized TiO2 NPs within SiO2 MSs with interconnected macroporosity, which will be assessed for the degradation of MO and paracetamol, under simulated solar illumination It involves much more than a conventional photocatalytic system for water purification, which typically relies on photocatalytic NPs dispersed in the liquid reaction medium (slurry reactor, batch process) and time-consuming and complex nanofiltration process for recovery of the catalysts. The target of this technology is for developing countries, and for developed countries, especially in what regards wastewater decontamination in industrial processes
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