Photocatalytic Water Disinfection under Solar Irradiation by d-Glucose-Modified Titania

Abstract

Modified titania photocatalysts were synthesized by the pressure method using titanium(IV) oxide from Grupa Azoty Zakłady Chemiczne “Police” S.A., Police, Poland, and d-glucose solution. Characterization of obtained composites was performed by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), elemental analysis, and measurements of zeta potential and specific surface area (SSA). The possibility of using glucose-titania composites as photocatalysts for simulated solar-assisted disinfection against gram-negative Escherichia coli and gram-positive Stapchyloccocus epidermidis bacteria were examined in two reaction systems, i.e., for suspended and immobilized photocatalysts (on the concrete). It was found that an increase in the d-glucose concentration, i.e., higher carbon content, led to a decrease in antibacterial properties. The sample obtained from 1% of d-glucose solution at 100 °C (TiO2-1%-G-100) showed superior photocatalytic activity under UV-Vis irradiation toward both bacteria species. Water disinfection was more efficient for suspended photocatalyst than that for supported one, where complete disinfection was reached during 55–70 min and 120 min of irradiation, respectively. For the first time, it has been shown that titania modified with monosaccharides can be efficiently used for water disinfection, and the immobilization of photocatalyst on the concrete might be a prospective method for public water supplies.

An approach to the photocatalytic mechanism in the TiO2-nanomaterials microorganism interface for the control of infectious processes

“…Other carbonaceous material, the chitosan, has also been used in the preparation of TiO2 nanocomposites for the inactivation of Escherichia coli and Staphylococcus aureus [136]. The simplest procedure for carrying out the preparation of Cdoped TiO2 is the use of carbohydrates, such as glucose and sucrose as carbon precursors [141,142]. In addition, it is worth noting the carbon doping of TiO2.…”

Carbon/Graphene-Modified Titania with Enhanced Photocatalytic Activity under UV and Vis Irradiation

“…Moreover, Cruz-Ortiz et al reported that TiO 2 -rGO showed significant bactericidal activity (E. coli) under visible light irradiation, due to the generation of singlet oxygen [79]. Accordingly, Markowska et al found enhanced generation of hydroxyl radicals and decrease in cell viability (via activity of antioxidant enzymes, morphology change and mineralization) on glucose-modified titania under artificial solar irradiation [15]. Therefore, our results confirm high activity of carbon-modified samples under vis irradiation for bacteria inactivation, probably via generated ROS.…”

“…Various sources of carbon have been proposed for titania modification, such as polyvinyl alcohol [10], n-hexane [11], alcohols (methyl, ethyl, isopropyl, n-butyl, 2-butyl and tert-butyl alcohols) [12], benzene [13], ethylene glycol and pentaerythritol [14] and glucose [15]. Interesting approach was proposed for carbon-doped titania nanostructures (micro-and nanospheres and nanotubes), synthesized via a single source vapor deposition in an inert atmosphere (Ar), where titanium butoxide (common organic precursor of titania) was used also as a carbon source [16].…”

Overview of Photocatalytic Membrane Reactors in Organic Synthesis, Energy Storage and Environmental Applications

“…The first one is represented by the so-called integrative-type PMRs, in which the photocatalytic reaction and MS take place in one apparatus, i.e., an inorganic or polymeric membrane submerged in the slurry photocatalytic reactor [25,26]. The second category comprises the so-called split-type PMRs.Here the photocatalytic reaction and MS take place in two separate apparatuses, the photocatalysis and membrane modules, which are appropriately coupled [27][28][29].PMRs with immobilized photocatalyst, indicated as PMRs with photocatalytic membrane (PM) [30], are intrinsically integrative-type; the photocatalytic and the membrane separation processes take place in the same unit.Additionally, on the basis of a different approach, the PMRs can also be classified considering the position of the light source, which can be: (i) above/inside the feed tank; (ii) above/inside the membrane unit; and, (iii) above/inside an additional vessel placed between the feed tank and the membrane unit [24].Because of the larger active surface area, which guarantees a good contact between the photocatalyst and the pollutants, it has been reported that PMRs with suspended photocatalyst make it possible to achieve higher efficiency when compared to that of the immobilized system [1,23,31]. As a consequence, the configurations with suspended catalyst have been largely…”

“…Because of the larger active surface area, which guarantees a good contact between the photocatalyst and the pollutants, it has been reported that PMRs with suspended photocatalyst make it possible to achieve higher efficiency when compared to that of the immobilized system [1,23,31]. As a consequence, the configurations with suspended catalyst have been largely…”