Enhanced photocatalytic activity of TiO2 supported on zeolites tested in real wastewaters from the textile industry of Ethiopia (original) (raw)
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TiO2–Zeolite Metal Composites for Photocatalytic Degradation of Organic Pollutants in Water
Catalysts
Immobilization of photocatalysts in porous materials is an approach to significantly minimize the hazards of manipulation and recovery of nanoparticles. Inorganic materials, such as zeolites, are proposed as promising materials for photocatalyst immobilization mainly due to their photochemical stability. In this work, a green synthesis method is proposed to combine TiO2-based photocatalysts with commercial ZY zeolite. Moreover, a preliminary analysis of their performance as photocatalysts for the abatement of organic pollutants in waters was performed. Our results show that the physical mixture of TiO2 and zeolite maintains photocatalytic activity. Meanwhile, composites fabricated by doping TiO2–zeolite Y materials with silver and palladium nanoparticles do not contribute to improving the photocatalytic activity beyond that of TiO2.
Journal of the Taiwan Institute of Chemical Engineers, 2015
Photocatalysis usually involves the utilisation of nano-sized semiconductor photocatalysts owing to their higher specific surface area and surface reaction rate. However, the key challenges in the utilisation of nanosized photocatalysts for advanced treatment of industrial dye wastewater are to enhance the post-separation and recovery of spent photocatalysts to prevent them from diffusing into the environment. Thus, the main aim of this study was to synthesize a functional-form of titanium dioxide (TiO 2 )-zeolite nanocomposite through the modified two-step sol-gel method for enhanced application and separation after advanced industrial dye wastewater treatment. The synthesized TiO 2 -zeolite nanocomposite was characterised using field-emission scanning electron microscopy (FE-SEM), energy dispersive X-ray (EDX) analysis, Fourier-transformed infrared spectroscopy (FTIR), particle size distribution analysis and Brunauer-Emmett-Teller (BET) specific surface area and porosity analysis. Subsequently, the photoactivity of synthesized TiO 2 -zeolite nanocomposite was measured and compared against the commercial TiO 2 particles. It was found that the TiO 2 -zeolite nanocomposite shows a high apparent pseudo-first order reaction rate constant of 0.0419 min −1 at lower dye concentration. This showed that the synthesized TiO 2 -zeolite nanocomposite follows a more adsorptionoriented photocatalytic degradation of water pollutants, which is useful for removing trace and untreated dye compounds in the advanced industrial dye wastewater treatment stage.
Structural and Photocatalytic Properties of TiO2/Zeolite Synthesized using Sol-Gel Method
ALCHEMY, 2019
Titanium dioxide (TiO2) is supported into natural zeolite to enhance its photocatalytic activity. TiO2/zeolite is synthesized using sol-gel method at composition ratio of 5:95; 10:90; 20:80 and 30:70%. Structural properties are measured by X-ray diffraction showed TiO2/zeolite in various composition has characteristic of anatase and modernite phase. The energy dispersive spectroscopy characterization shows TiO2/zeolite containing Ti element which indicates that TiO2is successfully supported into natural zeolite. Vibration mode of Infrared and Raman spectra tend shifted to higher wavenumber as increasing of TiO2 content indicating the higher energy vibration due to molecular interaction between TiO2 and zeolite. Photocatalytic activity test toward methylene blue degradation shows that TiO2/zeolite has higher activity than TiO2 and zeolite itself.Keywords: Photocatalyst, titanium dioxide, zeolite
Journal of Nanomaterials, 2015
In this research different composites of impregnated TiO2with LTA or FAU zeolites were used as different weight% ratio for photodegradation of organic dye. Normal laboratory UV-lamps were used as a source of UV irradiation. In addition a setup of system of mirrors was used to collect real Jeddah sunlight. A comparison of UV and real sunlight photodegradation activity showed that the real sunlight enhances new centers of active sites exhibiting higher catalytic activity than that of UV irradiated samples.
Enhanced photocatalytic activity of supported TiO2: dispersing effect of SiO2
Journal of Photochemistry and Photobiology A: Chemistry, 1999
Zeolite Y was treated using ammonium acetate and ammonium fluoride sequentially. As a consequence the aluminum from the surface was selectively removed. Then, loading with TiO 2 (20 wt%) led to a final photocatalyst. The samples were characterized by X-ray diffraction (XRD), elemental analysis (ICP-OES), N 2 adsorption, diffuse reflectance UV-vis spectroscopy (DRS), photoluminescence spectroscopy (PL), and X-ray photoelectron spectroscopy (XPS). It was found that 50% of the Al atoms were removed from the surface of the zeolite without affecting the framework structure. The TiO 2 /treated zeolite sample yielded 92% photocatalytic degradation of 10 ppm methyl orange (MO), a model pollutant, while the TiO 2 /parent zeolite converted only 7.6%. The mass normalized turnover rate (TOR m) of the treated zeolite loaded with TiO 2 was about 12 times higher than that of the parent zeolite loaded with the same amount of TiO 2 precursor. This higher photocatalytic activity of the TiO 2 supported on treated zeolite can be attributed to a more efficient interaction of the TiO 2 with the zeolite leading to higher adsorption capacity. Reusability of the photocatalysts was assessed by performing three consecutive reaction cycles that showed no significant loss of photocatalytic activity.
Synthesis of TiO2/Zeolite-A Composite for The Removal of Methylene Blue on Direct Sunlight
Jurnal Teknik ITS, 2019
Wastewater generated from textile industry contains azo dye, (e.g., methylene blue), which is inefficient to decompose by using biological processes, and requires long treatment time. TiO2 is the most widely used adsorbent for industrial applications and photocatalytic degradation of various azo dyes in textile wastewater. Its anatase is the most effective and widely used photocatalyst, however the wide band gap of TiO2 has limited its widespread application in industry since it needs to be excited by ultraviolet (UV) light. In order to overcome this issue, combination of adsorbent zeolite and TiO2 into the composite was used in this study so that TiO2 can adsorb methylene blue under direct sunlight. Composition of 1 g TiO2 and 1 g Zeolite composite was used in batch method to eliminate different methylene blue concentrations, i.e., 25; 50; 75; 100; 125; 150; 200; and 250 ppm by means of adsorption process under direct sunlight. The experimental result showed that addition of zeolit...
Carbon-/Zeolite-Supported TiO2 for Sorption/Photocatalysis Applications in Water Treatment
Photocatalysts - Applications and Attributes [Working Title]
The role of various carbon forms, i.e., activated carbon and carbon nanotubes/nanofibers as support for TiO 2 in drinking water treatment, is discussed. Also, TiO 2 supported onto zeolite that acts bifunctionally as a sorbent/photocatalyst for drinking water treatment is presented. The main contaminants of natural organic matter (NOM), arsenic species, and nitrogen compounds from drinking water sources by the type of groundwater and surface water can be removed/degraded by sorption/photocatalysis using TiO 2 supported onto carbon and/or zeolite. TiO 2 supported on powdered activated carbon (PAC-TiO 2), granular activated carbon (GAC-TiO 2), and zeolite (Z-TiO 2), namely, supported TiO 2 , was synthesized through the sol-gel method, and TiO 2 and multiwall carbon nanotubes/ carbon nanofibers dispersed within epoxy matrix (CNT-TiO 2-Epoxy, CNF-TiO 2-Epoxy), namely, TiO 2 composite, were obtained through the two-roll mill method. Kinetic study results through specific mathematic models allowed to elucidate some mechanistic aspects for sorption and photocatalysis for the application in drinking water. The intercalation of the carbon-and zeolite-supported TiO 2 layers into a filtering system allows to develop a self-cleaning filtering system in drinking water.
Applied Catalysis B: Environmental, 2015
Materials based on titania supported on zeolitic matrices (HBETA, HY and HZSM5) were synthesized by in situ generation of TiO 2. The supported catalysts characterized by XRD indicate the presence of the anatase phase alone. The materials were also characterized by FTIR, S BET , and UV-VIS DRS. A high TiO 2 content produced lower degradation, due to the presence of TiO 2 particle aggregates of greater size on the zeolite matrix surface, as evidenced by the calculated crystal size. TiO 2 /HBETA(20%) presented more activity than TiO 2 supported on the other matrices due to higher adsorption of dichlorvos on HBETA. It has more surface area and a lower band gap value too, which makes it more effective. The mineralization degree is lower than the degradation percentage due to the formation of organophosphorous intermediates that are less toxic than the starting material. The complete degradation and mineralization of the pollutant was obtained in 360 and 540 min of reaction with TiO 2 /HBETA(20%), respectively. This catalyst resulted in degradation percentages close to that of commercial TiO 2 P25. The main advantage of supported catalysts is their easy separation and reuse, in this case resulting in a very low activity loss during eight cycles. These materials present suitable properties to be used as catalysts in the photocatalytic treatment of wastewater that contains pesticide dichlorvos in water.
Photochemical & Photobiological Sciences, 2022
A low-cost NaP zeolite@TiO 2 nanocomposite catalyst with zeolite Si/Al ratio lower than three were synthesized for the first time under hydrothermal condition. The nanocomposites were characterized by different methods such as Fourier transform infrared (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), diffuse reflectance spectroscopy (DRS), N 2 physisorption, NH 3 temperature-programmed desorption (NH 3-TPD), fluorescence microscopy, thermal analysis (TGA/DTA) and zeta potential analysis. The results showed that a micro-meso structure NaP zeolite with higher surface area and acidity with respect to pure zeolite was prepared. TiO 2 nanoparticle was dispersed over the whole of zeolite without aggregation. A reduction of the TiO 2 bandgap nanoparticle was observed from DRS spectra. The photocatalytic activity of low-cost NaP zeolite@TiO 2 nanocomposite was tested for simultaneous methylene blue dye (MB) and chemical oxygen demand (COD) under solar and ultraviolet light. The result showed that the nanocomposite catalyst has great potential (above 90%) for COD removal discolouring of MB (about 99.6%) at room temperature. The optimum amount of some parameters such as the loaded amount of TiO 2 (0.36 g), catalyst dosage (0.1 g), time (2 h), initial dye concentration (100 mg/L), solution pH value (about 7) under solar light were considered. In addition, present negative charge in the surface that show in zeta potential confirm the high activity of catalyst to interaction with cationic dye. As a further advantage, the NaP zeolite@TiO 2 nanocomposite was easier to be separated in aqueous media than the pure TiO 2 powders, making possible the reuse several times (over five runs) without using oxidant. Finally, the NaP zeolite@TiO 2 nanocomposite was used for COD abatement in wastewater from two real industrial streams. The MB degradation kinetics were fitted by a pseudo-first-order model with K = 0.534 h −1 .