Photocatalytic treatment of saccharin and bisphenol-A in the presence of TiO 2 nanocomposites tuned by Sn(IV)

Abstract

This study deals with the photocatalytic treatment of saccharin (SAC) and bisphenol-A (BPA) under UV irradiation. For this purpose, novel submicronic anatase-rutile nanocomposite particles with tuned phase ratio produced by thermohydrolysis of acidic Ti(IV) solutions in the presence of controlled amounts of Sn(IV) were used. These catalysts were then assessed regarding their efficiency to degrade SAC or BPA, which are contaminants of increased environmental and health concern. The effect of various operating conditions, such as the anatase-rutile ratio (100:0, 85:15, 70:30), catalyst concentration (50-600 mg/L) and solute concentration (3-10 mg/L) was investigated. Furthermore, catalyst reuse-an important but little studied aspect-was assessed. Anatase-rutile nanocomposites were successfully prepared presenting good crystallinity and surface quality. Their activity was about the same for removing SAC or BPA from water. It was found that photocatalytic performance was increased with catalyst loading up to 400 mg/L. A further increase to 600 mg/L did not significantly enhance BPA removal, thus associating this tendency with screening effects. Also, photocatalytic efficiency was increased with initial solute concentration decrease. Organics degradation followed a pseudo-first order kinetic rate in terms of both SAC and BPA removal. The reproducibility of catalyst activity was assessed in three successive reuse cycles, where the removal percentage of initially 5 mg/L SAC was maintained as high as 70% at the end of the 3 rd cycle, in the presence of initially 400 mg/L anatase catalyst, and after 90 min of treatment. Finally, additional experimental runs were carried out with ultrasound cleaning (US) being applied to the reactant mixture at the beginning of each reuse cycle, but it was found to have no significant effect on treatment efficiency.

Photocatalytic degradation of saccharin under UV‐LED and blacklight irradiation

“…Leonardite humic acid IHSS standard was used and a stock solution was prepared by dissolving the proper amount of HA in 0.1 mol L ‐1 NaOH and further diluting it in deionised water. Aeroxide TiO 2 P25, supplied by Evonik Industries, was used as the photocatalyst because of its higher photocatalytic efficiency among other commercial catalysts, as was found also in our previous study …”

“…Aeroxide TiO 2 P25, supplied by Evonik Industries, was used as the photocatalyst because of its higher photocatalytic efficiency among other commercial catalysts, as was found also in our previous study. 12…”

“…TiO 2 -mediated photocatalysis, an advanced oxidation process with well-proven efficiency in degrading recalcitrant, non-biodegradable compounds, 9,10 has recently been studied for the degradation of SUC, ACE and SAC and the results obtained are encouraging. 8,11,12 In principle, photocatalytic oxidation is initiated upon UV illumination of TiO 2 ; highly reactive species, mainly hydroxyl radicals (HO • ), are then formed and non-selectively attack organic pollutants, which are subsequently mineralized into CO 2 and harmless inorganic products. 13,14 Blacklight (BL) fluorescent UV lamps are commonly used as irradiation source in photocatalytic applications.…”

Photocatalytic degradation of bisphenol A induced by dense nanocavities inside aligned 2D-TiO2 nanostructures

“…The mobile phase was a mixture of 35:65 UPW:acetonitrile fed at a flow rate of 1 mL/min [46]. The solvents were eluted isocratically and the injection volume was 40 μL.…”

Removal of Endocrine Disrupting Chemicals from Water: Adsorption of Bisphenol-A by Biobased Hydrophobic Functionalized Cellulose

“…Several technologies, such as coagulation/flocculation/sedimentation/filtration [ 17 , 18 ], carbon nanomaterials (CNMs) (e.g., carbon nanotubes (CNTs) [ 19 ] and graphene oxides (GOs) [ 20 ]), membrane filtration [ 21 , 22 ], ultraviolet (UV) irradiation [ 23 , 24 ], biological processes [ 25 , 26 ], and advanced oxidation techniques [ 27 , 28 , 29 , 30 , 31 ] have been studied for BPA removal. Nevertheless, energy consumption, low process efficiency, production of toxic by-products, and addition of hazardous chemicals prevent the wider application of all these technologies at large-scale.…”