Novel Removal of Diazinon Pesticide by Adsorption and Photocatalytic Degradation of Visible Light-Driven Fe-TiO<sub>2</sub>/Bent-Fe Photocatalyst

Phuong, Nguyen Minh; Chu, Ngoc Chau; Van Thuan, Doan; Ha, Minh Ngoc; Hanh, Nguyen Thi; Viet, Huong Do Thi; Minh Thu, Nguyen Thi; Van Quan, Pham; Thanh Truc, Nguyen Thi

doi:https://doi.org/10.1155/2019/2678927

Journal of Chemistry

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Abstract Introduction Experimental Results and Discussion Conclusion Data Availability Conflicts of Interest Acknowledgments References Copyright Related Articles

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Advanced Nanomaterials for Green Growth

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Research Article | Open Access

Volume 2019 | Article ID 2678927 | https://doi.org/10.1155/2019/2678927

Novel Removal of Diazinon Pesticide by Adsorption and Photocatalytic Degradation of Visible Light-Driven Fe-TiO₂/Bent-Fe Photocatalyst

Nguyen Minh Phuong,¹Ngoc Chau Chu,¹Doan Van Thuan,²Minh Ngoc Ha,¹Nguyen Thi Hanh,³Huong Do Thi Viet,¹Nguyen Thi Minh Thu,¹Pham Van Quan,⁴and Nguyen Thi Thanh Truc⁵

Guest Editor: Ajit Kumar Sharma

Received11 Dec 2018

Revised26 Jan 2019

Accepted13 Feb 2019

Published20 Mar 2019

Abstract

In the study, Fe was used as a dopant to enhance photocatalytic activity of TiO₂. Then, the Fe-doped TiO₂ was deposited on bentonite, which was pillared by Fe. The synthesized materials were characterized by SEM, XRD, UV-Vis, BET, and point of zero charge (pH_PZC). Then, the synthesized materials were used for diazinon removal under both dark and visible light conditions to investigate adsorption and photocatalytic degradation abilities of the synthesized materials. The maximum diazinon adsorption capacity of the synthesized Fe-TiO₂/Bent-Fe was 27.03 mg/g. The obtained results indicated that the Fe-TiO₂/Bent-Fe exhibited high photocatalytic degradation activity for removal of diazinon even under visible light. The diazinon removal experiments were also conducted using different photocatalyst dosages, under different pH and light sources to figure the optimal conditions for removal processes. The obtained results indicated that optimal photocatalyst dosage and pH were 0.5 g/L and 4.5, respectively. Finally, the natural light generated from solar could be suitable used for diazinon removal by the synthesized Fe-TiO₂/Bent-Fe.

1. Introduction

Many kinds of pesticides releasing into the environment as a result of runoff from agricultural and urban areas cause pollution of soil, air, surface water, and groundwater and are harmful for the human health [1, 2]. Among them, diazinon (O, O-diethyl O-[6-methyl-2-(1-methylethyl)-4-pyrimidinyl] phosphorothioate), an organophosphorus and highly toxic pesticide, is extensively used to control insects and, just in the USA, 6 million pounds of the pesticide are annually used on farming sites [3]. The diazinon has been classified as moderately hazardous class II chemical to humans, aquatics, mammals, and other species by the World Health Organization (WHO). Shemer and Linden reported that the fatal human doses of diazinon were in the range from 90 to 444 mg·kg⁻¹ [4]. Kouloumbos et al. reported that toxic effects of the pesticide attributed to its inhibition of the enzyme acetylcholinesterase affecting the nervous system [5]. Therefore, water systems contaminated with diazinon have been treated by various techniques such as adsorption, filtration, membrane separation, biodegradation, oxidation, and chemical coagulation [6]. However, these methods have several certain disadvantages including incomplete removal, high consumption of chemicals, time consuming, and high treatment cost.

Recently, advanced oxidation processes (AOPs), using heterogeneous photocatalysts to produce hydroxyl radicals (OH), a strong oxidative agent, to totally promote mineralization of organic pollutants into harmless substances such as CO₂ and H₂O, could be a potential technology for removal of diazinon [7–9]. Titanium oxide (TiO₂) is regarded as the most suitable photocatalyst for the degradation of organic pollutants from wastewaters because of its chemical stability, nontoxicity, low cost, and commercial availability [10–12]. However, because of wide band gap of TiO₂, which is approximately 3.2 eV, the photocatalyst could only be activated by UV irradiation, which only accounts for 3-4% of the solar spectrum [13, 14]. The high-energy consumption and safety issues concerning use of UV irradiation are the main disadvantages of TiO₂ in the practical system. In addition, the fast recombination of the photoexcited electrons and holes is also another disadvantage of the TiO₂ photocatalyst. Hence, numerous studies have been conducted to effectively enhance the photocatalytic activity of TiO₂ and to expand its applications in practical systems using visible light or the solar energy as the excitation source [15–21]. Among these, metals have been used as doping agents to implant or incorporate into the TiO₂ lattice to narrow the band gap of the photocatalyst, thereby enhancing its photocatalytic activity [22–27]. The overlap between d orbital of the substituted metal and d orbital of titanium could narrow band gap or facilitate the visible light absorption of the doped TiO₂, leading to its photocatalytic enhancement [28]. Therefore, the first aim of the study is to use Fe as dopant to enhance photocatalytic activity of TiO₂ to utilize visible light as excitation sources for its photocatalytic removal of diazinon.

In addition, it is difficult to recover powder photocatalysts after being used in practical system for wastewater treatment. Moreover, the photocatalytic activity of a certain photocatalyst strongly depends on its adsorption capacity [29]. Various materials including activated carbon, glass fiber, polyurethane, silica, alumina, and bentonite have been used as supports to fix photocatalysts to overcome such limitations. In the study, bentonite, which is nontoxic, porous, economical, easily available in our country (Vietnam), and also chemically and mechanically stable, was used as support materials for Fe-doped TiO₂ (Fe-TiO₂). However, the surface area of the natural bentonite is quite small. Many studies reported that the introduction of the inorganic pillars into bentonite could increase its surface area, pore volume, microporosity, and thermal stability [30–32]. Therefore, the study used Fe as a pillar to increase surface area as well as pore volume of the bentonite before being used as support for the Fe-TiO₂. Thus, the Fe-doped TiO₂ supported on bentonite pillared Fe (Fe-TiO₂/Bent-Fe) would have high photocatalytic activity and adsorption capacity for removal of diazinon.

2. Experimental

2.1. Material Preparation

First, 10 g bentonite was saturated with Fe³⁺ in 100 mL of 1 M solution of FeCl₃ under constant stirring. The obtained suspension was continuously stirred at room temperature for 24 h. The resulting product was centrifuged and washed by distilled water until chloride free (tested by AgNO₃). The obtained material was dried at 363 K for 12 h and then milled to get bentonite-pillared Fe (Bent-Fe). Then, the obtained Bent-Fe was swelled in pure ethanol solution with weight ratio of 2%. Second, 6 mL tetra isopropyl orthotitanate (TIOT) was slowly dropped into 34 mL ethanol to get a solution “A” while 48.2 mg Fe(NO₃)₃·9H₂O was diluted in a solution containing 17 mL ethanol, 0.4 mL HNO₃ (68%), and 1.6 mL distilled water to obtain a solution “B”. Then, the solution “A” was slowly dropped into the solution “B” to get sol Fe-TiO₂. Finally, the obtained sol Fe-TiO₂ was slowly dropped into the swelled Bent-Fe with continuously stirring for 4 h and aging for 24 h. The obtained mixture was changed into a Teflon-lined stainless steel autoclave and then heated under 160°C for 6 h. After the autoclave was cooled to room temperature, the precipitate at the bottom of the autoclave was obtained and washed with ethanol and deionized water several times. The product was dried at 80°C for 24 h to get Fe-TiO₂/Bent-Fe. The weight ratio of (Fe-TiO₂)/(Bent-Fe) was 3 : 1.

2.2. Photocatalyst Characterization

The surface morphology of the synthesized materials was analyzed using a JED-2300-Analysis Station Plus, JEOL scanning electron microscope (SEM). X-ray diffraction (XRD) spectra of the synthesized TiO₂, Fe-TiO₂, Fe-TiO₂/Bent, Bent-Fe, and Fe-TiO₂/Bent-Fe materials were obtained using a D8-Advance 5005 model with Cu-Kα (λ = 1.5406 Å) radiation over the range 10° < 2θ < 70°, at a scanning rate of 0.03°/min. The optical absorption abilities of the synthesized photocatalysts were characterized by an UV 3101PC spectrophotometer, Shimadzu. The point of zero charge (pH_PZC) of the synthesized material was determined using the procedure as follows: a 50 mL of 0.01 M NaCl were placed into several closed Erlenmeyer flasks and the pH of each flask was adjusted at 3.0, 4.5, 5.6, and 8.0 by adding HCl (0.01 M) or NaOH (0.01 M). Then, 0.2 g Fe-TiO₂/Bent-Fe was added to each flask. The pH_PZC is the point where the line of final pH is crossing the line of initial pH.

2.3. Removal Experiments

Experiments were conducted to investigate diazinon removal efficiency by adsorption and photocatalytic degradation of the synthesized materials. In addition, optimal pH, photocatalyst dosage, and light condition were also investigated in the study. In a typical removal experiment, a known dosage of the synthesized photocatalyst (0.25–1 g/L) was transferred to 100 mL of diazinon solution with a distinct concentration (10–50 mg/L) at a certain pH (3–8). The initial pH of solution was adjusted by adding NaOH or HCl (0.1 mol/L) and measured by the pH meter model XT 1200C (Mettler Toledo). After a certain time, the mixture was filtered and the remained diazinon concentrations were measured using a HPLC (Supelco LiChrospher RP-18 column, 250 × 4.6 × 5) coupled to a UV-PDA detector (Shimadzu SPD–M10Avp) at a wavelength of 247 nm. The removal experiment was firstly conducted under dark condition to determine adsorption capacity of the synthesized material. Then, the visible light was provided to initiate for photocatalytic degradation of diazinon.

3. Results and Discussion

3.1. Material Characteristics

3.1.1. Morphology

Figure 1 shows the SEM images of the synthesized Bent-Fe and Fe-TiO₂/Bent-Fe materials. It can be seen that the synthesized Bent-Fe material existed in form of nanolamella with dominant flake-like morphology and curling edges. The SEM image of the synthesized Fe-TiO₂/Bent-Fe indicated that Fe-TiO₂ particles existed in form of nanospherical particles. The nano-Fe-TiO₂ particles were well-dispersed on the surface of the Bent-Fe layers. This is expected to increase recycling ability of the nano-Fe-TiO₂ photocatalysts after being used for diazinon removal processes. In addition, the deposition of Fe-TiO₂ particles on the surface of the Bent-Fe could increase surface areas of the material, leading to increase in its diazinon removal efficiency. The BET surface area of the synthesized Fe-TiO₂/Bent-Fe (181.13 m²/g) was greatly higher than that of the Bent-Fe (66.22 m²/g).

3.1.2. Crystal Phase Structure

Figure 1 shows the XRD patterns of undoped TiO₂, Fe-TiO₂, and Fe-TiO₂/Bent-Fe materials. It can be seen that the anatase and rutile phases were observed in the XRD pattern of the undoped TiO₂ material (JCPDS card No. 65-5714 for anatase and JCPDS card no. 21-1276 for rutile). However, there was only anatase phase in the XRD pattern of the synthesized Fe-TiO₂ photocatalyst. This could be due to the incorporation of Fe dopant into TiO₂ lattice prevented the formation of the rutile phase [33, 34]. There was no peak corresponding to Fe component in the synthesized Fe-TiO₂ material which confirmed that Fe incorporated in the TiO₂ lattice. Figure 1 also shows that the phase structure of the Fe-TiO₂ photocatalyst unchanged when the material was deposited on the Bent-Fe. In addition, a peak corresponding to the montmorillonite phase of the bentonite was also observed in the XRD pattern of the Fe-TiO₂/Bent-Fe material (JCPDS card No. 03-0014) (Figure 2).

3.1.3. Optical Properties

Figure 3 shows the UV-Vis light absorption of the synthesized TiO₂, Bent-Fe, Fe-TiO₂, and Fe-TiO₂/Bent-Fe materials. The UV-Vis absorption spectrum of TiO₂ exhibited an absorption edge at 390 nm [35]. However, the materials did not exhibit any noticeable absorption in the visible region. Bent-Fe also shows little visible light absorption. As compared to the UV-Vis absorption spectra of the TiO₂ and Bent-Fe, that of the Fe-TiO₂, however, not only showed a red shift of the absorption edge but also exhibited higher adsorption ability in the visible region. The band gap structure of the TiO₂ is comprised of a valence band, which is mainly constructed from an O 2p orbital, and a conduction band, which is mainly constructed from an empty Ti 3d orbital. In the Fe-TiO₂, the 3d orbitals of Fe dopant not only affected to the top of the valence band and the bottom of the conduction band of the TiO₂ but also inserted into the TiO₂ lattice structure to create a Fe impurity band under the conduction band and upper the valence band of the TiO₂, formed an optical band gap [33, 36]. Therefore, the photoexcited electrons in the TiO₂ valence band could migrate to the Fe impurity band, and then move from the impurity band to the conduction band via next photon absorption. Thus, the Fe dopant led to decrease in the band-gap energy, recombination rate of photo-excited electrons and holes, as well as increase in visible light absorption of the TiO₂. The UV-Vis absorption spectrum of Fe-TiO₂/Bent-Fe shows that the deposition of the Fe-TiO₂ on the surface of the Bent-Fe extended visible light absorption of the Fe-TiO₂. Krishnan and Mahalingam reported that the increase in visible light absorption was due to the interband transitions i.e., charge transfer transition of interlayer tetrahedral and octahedral atoms in the bentonite material [37].

3.2. Diazinon Removal

3.2.1. Adsorption of Diazinon

First, the effect of contact time on the sorption of diazinon was investigated by adding 0.5 g of the synthesized Fe-TiO₂/Bent-Fe material in 100 mL diazinon solution (16.74 mg/L) at pH 5.6 (natural pH without any adjustment) and room temperature of 25°C. The diazinon adsorption capacities by the synthesized Fe-TiO₂/Bent-Fe are shown in Figure 4(a). It can be seen that the diazinon adsorption capacities increased with increase in contact time up to 30 min and then tend to stabilize with further increase in contact time. It means that the diazinon adsorption by the synthesized Fe-TiO₂/Bent-Fe reaches the equilibrium after 30 min. Based on the obtained results, the experiments, which the contact time was fixed (30 min), were conducted to investigate maximum diazinon adsorption capacity of the synthesized Fe-TiO₂/Bent-Fe. The Langmuir model was applied to calculate the maximum adsorption capacities (Figure 4(b)). It can be seen that the adsorption ability is suitable with the Langmuir model, and the maximum diazinon adsorption capacity (q_max) by the synthesized Fe-TiO₂/Bent-Fe was 27.03 (mg/g).

(a)

(b)

3.2.2. Photocatalytic Degradation of Diazinon

In order to investigate photocatalytic degradation of diazinon, 0.5 g Fe-TiO₂/Bent-Fe material was put in 100 mL diazinon solution (25 mg/L). In the condition, the pH of solution was 5.6 (natural pH without any adjustment). Then, the obtained solution was kept in dark condition for 30 min to get adsorption equilibrium, and then the visible light was provided using a 36 W compact bulb, which could provide visible light in range of 400–700 nm. The diazinon removal results are shown in Figure 5. Under dark condition, an approximately 36.18% diazinon was removed by adsorption of Fe-TiO₂/Bent-Fe material. When visible light was provided, the diazinon was continuously removed by photocatalytic degradation. The synthesized Fe-TiO₂/Bent-Fe could absorb significant amount of incident light to generate huge amount of electrons and holes. Then, the generated electrons and holes could react with H₂O and O₂, respectively, to produce strong oxidative radicals, including hydroxyl and superoxide anion radicals, for degradation of diazinon into harmless inorganic materials [38–40]. The total diazinon removal by both adsorption and photocatalytic degradation was approximately 58.3%.

3.2.3. Optimal Removal Conditions

The effects of photocatalyst dosages on diazinon removal efficiencies are shown in Figure 6(a). When the photocatalyst dosage was 0.25 g/L, the amount of photocatalyst was not enough for the diazinon removal. The diazinon removal efficiencies increased with increase in photocatalyst dosage up to 1.0 g/L. When the photocatalyst dosages increased, the turbidity of the solution increased. An increased level of suspension turbidity resulted from excessive photocatalyst dosage would block the incident visible light required for the photocatalyst activation [41]. Hence, the photocatalytic degradation efficiency decreased. Thus, the optimal photocatalyst dosage for diazinon removal was 0.5 g/L.

The diazinon removal experiments was conducted under different light conditions including artificial light generated from compact bulb and natural light from solar. The intensity of light from the 36 W compact bulb was 190.985 lux and the intensity of solar light, which was measured in 6 hours of the experiment, varied from 32.500 to 65.200 lux. In the experiments, the photocatalytic dosage, pH, and intimal concentration of diazinon were 0.5 g/L, 5.6, and 25 ppm, respectively. The obtained results are shown in Figure 6(b). The diazinon removal efficiency under natural light generated from solar was 53%, which was slightly lower than that under artificial light generated from compact bulb (58.3%). Thus, the natural light could be suitable used for photocatalytic degradation of diazinon by the synthesized Fe-TiO₂/Bent-Fe material.

Finally, the diazinon removal experiments were conducted at different pH (3.0, 4.5, 5.6 and 8.0) to investigate optimal pH for the process. In the experiments, the photocatalytic dosage and intimal concentration of diazinon were 0.5 g/L and 25 ppm, respectively. The diazinon removal efficiencies at different pH are shown in Figure 6(c). First, the of diazinon is 2.6, thus diazinon is negatively charged at all the selected pH conditions [2]. Point of zero charge of the synthesized Fe-TiO₂/Bent-Fe material was approximately 4.6 (Figure 6(d)). As expected, an optimal condition can be developed in the pH range between and at which the positively charged Fe-TiO₂/Bent-Fe material and negatively charged diazinon should readily attract each other. At high pH, both diazinon and Fe-TiO₂/Bent-Fe have negative charges. Therefore, electrostatic repulsion between diazinon and Fe-TiO₂/Bent-Fe causes reduced adsorption of diazinon onto material surface, resulting in decreased photocatalytic removal efficiency. Based on the obtained results of this study, pH 4.5 was identified as an optimum condition for the removal of diazinon using Fe-TiO₂/Bent-Fe material. Under optimal conditions, including dosage (0.5 g/L) and pH (4.5), 80.6% diazinon, which the initial concentration was 25 ppm, has been removed by the synthesized Fe-TiO₂/Bent-Fe.

Recycling experiments were conducted to analyze the stability of the prepared photocatalyst during the diazinon removal processes. After being used for diazinon removal for 360 min, the photocatalysts were collected and vacuum dried for 4 h under the dark condition and then used for the diazinon removal experiment. The diazinon removal efficiency by Fe-TiO₂/Bent-Fe in the first and second time of recycle was 76.8 and 69.3%, respectively. The diazinon removal by Fe-TiO₂/Bent-Fe was not significantly changed after recycling, which demonstrated the stability of the photocatalysts during the removal experiments.

4. Conclusion

We successfully used Fe as a dopant to enhance photocatalytic activity of TiO₂. Then, the Fe doped TiO₂ was deposited on bentonite, which was pillared by Fe, to enhance its adsorption and recycling ability in the practical system. The synthesized material exhibited high adsorption ability to remove diazinon. The maximum diazinon adsorption capacity of the synthesized Fe-TiO₂/Bent-Fe was 27.03 mg/g. Even under visible light, the synthesized Fe-TiO₂/Bent-Fe photocatalyst also exhibited high photocatalytic activity for degradation of diazinon. The optimal photocatalyst dosage for removal of diazinon was 0.5 g/L. The natural light generated from solar could be suitable used for diazinon removal by the synthesized Fe-TiO₂/Bent-Fe. Finally, the optimal pH for diazinon removal was 4.5, which is preferred for adsorption of diazinon by the synthesized Fe-TiO₂/Bent-Fe.

Data Availability

The data used to support the findings of this study are included within the article.

Conflicts of Interest

The authors declare that they have no conflicts of interest.

Acknowledgments

This research was funded by the Vietnam National University, Hanoi (VNU), under project number QG.17.27.

References

A. F. Hassan, H. Elhadidy, and A. M. Abdel-Mohsen, “Adsorption and photocatalytic detoxification of diazinon using iron and nanotitania modified activated carbons,” Journal of the Taiwan Institute of Chemical Engineers, vol. 75, pp. 299–306, 2017.
View at: Publisher Site | Google Scholar
H. Hossaini, G. Moussavi, and M. Farrokhi, “Oxidation of diazinon in cns-ZnO/LED photocatalytic process: catalyst preparation, photocatalytic examination, and toxicity bioassay of oxidation by-products,” Separation and Purification Technology, vol. 174, pp. 320–330, 2017.
View at: Publisher Site | Google Scholar
A.-A. Salarian, Z. Hami, N. Mirzaei et al., “N-doped TiO₂ nanosheets for photocatalytic degradation and mineralization of diazinon under simulated solar irradiation: optimization and modeling using a response surface methodology,” Journal of Molecular Liquids, vol. 220, pp. 183–191, 2016.
View at: Publisher Site | Google Scholar
H. Shemer and K. Linden, “Degradation and by-product formation of diazinon in water during UV and UV/H₂O₂ treatment,” Journal of Hazardous Materials, vol. 136, no. 3, pp. 553–559, 2006.
View at: Publisher Site | Google Scholar
V. N. Kouloumbos, D. F. Tsipi, A. E. Hiskia, D. Nikolic, and R. B. Breemen, “Identification of photocatalytic degradation products of diazinon in TiO₂ aqueous suspensions using GC/MS/MS and LC/MS with quadrupole time-of-flight mass spectrometry,” Journal of the American Society for Mass Spectrometry, vol. 14, no. 8, pp. 803–817, 2003.
View at: Publisher Site | Google Scholar
V. N. Nguyen, D. T. Tran, M. T. Nguyen et al., “Enhanced photocatalytic degradation of methyl orange using ZnO/graphene oxide nanocomposites,” Research on Chemical Intermediates, vol. 44, no. 5, pp. 3081–3095, 2018.
View at: Publisher Site | Google Scholar
A. Jonidi-Jafari, M. Shirzad-Siboni, J.-K. Yang, M. Naimi-Joubani, and M. Farrokhi, “Photocatalytic degradation of diazinon with illuminated ZnO-TiO₂ composite,” Journal of the Taiwan Institute of Chemical Engineers, vol. 50, pp. 100–107, 2015.
View at: Publisher Site | Google Scholar
S. R. Mirmasoomi, M. Mehdipour Ghazi, and M. Galedari, “Photocatalytic degradation of diazinon under visible light using TiO₂/Fe₂O₃ nanocomposite synthesized by ultrasonic-assisted impregnation method,” Separation and Purification Technology, vol. 175, pp. 418–427, 2017.
View at: Publisher Site | Google Scholar
M. Shirzad-Siboni, A. Jonidi-Jafari, M. Farzadkia, A. Esrafili, and M. Gholami, “Enhancement of photocatalytic activity of Cu-doped ZnO nanorods for the degradation of an insecticide: kinetics and reaction pathways,” Journal of Environmental Management, vol. 186, pp. 1–11, 2017.
View at: Publisher Site | Google Scholar
E. Rossetto, D. I. Petkowicz, J. H. Z. dos Santos, S. B. C. Pergher, and F. G. Penha, “Bentonites impregnated with TiO₂ for photodegradation of methylene blue,” Applied Clay Science, vol. 48, no. 4, pp. 602–606, 2010.
View at: Publisher Site | Google Scholar
A. T. Kuvarega, R. W. M. Krause, and B. B. Mamba, “Evaluation of the simulated solar light photocatalytic activity of N, Ir co-doped TiO₂ for organic dye removal from water,” Applied Surface Science, vol. 329, pp. 127–136, 2015.
View at: Publisher Site | Google Scholar
T.-D. Pham and B.-K. Lee, “Advanced removal of C. famata in bioaerosols by simultaneous adsorption and photocatalytic oxidation of Cu-doped TiO₂/PU under visible irradiation,” Chemical Engineering Journal, vol. 286, pp. 377–386, 2016.
View at: Publisher Site | Google Scholar
N. A. Ramos-Delgado, M. A. Gracia-Pinilla, L. Maya-Treviño, L. Hinojosa-Reyes, J. L. Guzman-Mar, and A. Hernández-Ramírez, “Solar photocatalytic activity of TiO₂ modified with WO₃ on the degradation of an organophosphorus pesticide,” Journal of Hazardous Materials, vol. 263, pp. 36–44, 2013.
View at: Publisher Site | Google Scholar
T.-D. Pham, B.-K. Lee, and D. Pham-Cong, “Advanced removal of toluene in aerosol by adsorption and photocatalytic degradation of silver-doped TiO₂/PU under visible light irradiation,” RSC Advances, vol. 6, no. 30, pp. 25346–25358, 2016.
View at: Publisher Site | Google Scholar
V. Iliev, D. Tomova, L. Bilyarska, A. Eliyas, and L. Petrov, “Photocatalytic properties of TiO₂ modified with platinum and silver nanoparticles in the degradation of oxalic acid in aqueous solution,” Applied Catalysis B: Environmental, vol. 63, no. 3-4, pp. 266–271, 2006.
View at: Publisher Site | Google Scholar
K. Pathakoti, S. Morrow, C. Han et al., “Photoinactivation of Escherichia coli by sulfur-doped and nitrogen-fluorine-codoped TiO₂ nanoparticles under solar simulated light and visible light irradiation,” Environmental Science & Technology, vol. 47, no. 17, pp. 9988–9996, 2013.
View at: Publisher Site | Google Scholar
H.-Y. Lin and Y.-S. Chang, “Photocatalytic water splitting for hydrogen production on Au/KTiNbO₅,” International Journal of Hydrogen Energy, vol. 35, no. 16, pp. 8463–8471, 2010.
View at: Publisher Site | Google Scholar
M. Ni, M. K. H. Leung, D. Y. C. Leung, and K. Sumathy, “A review and recent developments in photocatalytic water-splitting using TiO₂ for hydrogen production,” Renewable and Sustainable Energy Reviews, vol. 11, no. 3, pp. 401–425, 2007.
View at: Publisher Site | Google Scholar
X. Chen, S. Shen, L. Guo, and S. S. Mao, “Semiconductor-based photocatalytic hydrogen generation,” Chemical Reviews, vol. 110, no. 11, pp. 6503–6570, 2010.
View at: Publisher Site | Google Scholar
T.-D. Pham and B.-K. Lee, “Novel integrated approach of adsorption and photo-oxidation using Ag-TiO₂/PU for bioaerosol removal under visible light,” Chemical Engineering Journal, vol. 275, pp. 357–365, 2015.
View at: Publisher Site | Google Scholar
T.-D. Pham and B.-K. Lee, “Cu doped TiO₂/GF for photocatalytic disinfection of Escherichia coli in bioaerosols under visible light irradiation: application and mechanism,” Applied Surface Science, vol. 296, pp. 15–23, 2014.
View at: Publisher Site | Google Scholar
H. Yan, S. T. Kochuveedu, L. N. Quan, S. S. Lee, and D. H. Kim, “Enhanced photocatalytic activity of C, F-codoped TiO₂ loaded with AgCl,” Journal of Alloys and Compounds, vol. 560, pp. 20–26, 2013.
View at: Publisher Site | Google Scholar
X. Xu, X. Zhou, L. Zhang et al., “Photoredox degradation of different water pollutants (MO, RhB, MB, and Cr(VI)) using Fe-N-S-tri-doped TiO₂ nanophotocatalyst prepared by novel chemical method,” Materials Research Bulletin, vol. 70, pp. 106–113, 2015.
View at: Publisher Site | Google Scholar
S. M. El-Sheikh, G. Zhang, H. M. El-Hosainy et al., “High performance sulfur, nitrogen and carbon doped mesoporous anatase-brookite TiO₂ photocatalyst for the removal of microcystin-LR under visible light irradiation,” Journal of Hazardous Materials, vol. 280, pp. 723–733, 2014.
View at: Publisher Site | Google Scholar
S. Yu, H. J. Yun, Y. H. Kim, and J. Yi, “Carbon-doped TiO₂ nanoparticles wrapped with nanographene as a high performance photocatalyst for phenol degradation under visible light irradiation,” Applied Catalysis B: Environmental, vol. 144, pp. 893–899, 2014.
View at: Publisher Site | Google Scholar
T.-D. Pham and B.-K. Lee, “Photocatalytic comparison of Cu- and Ag-doped TiO₂/GF for bioaerosol disinfection under visible light,” Journal of Solid State Chemistry, vol. 232, pp. 256–263, 2015.
View at: Publisher Site | Google Scholar
T. D. Pham, B. K. Lee, M. V. Nguyen, and C. H. Lee, “Germicide feasibility of TiO₂/glass fiber and Ag-TiO₂/glass fiber photocatalysts,” Advanced Materials Research, vol. 864, pp. 518–523, 2012.
View at: Google Scholar
H. Feng, M.-H. Zhang, and L. E. Yu, “Hydrothermal synthesis and photocatalytic performance of metal-ions doped TiO₂,” Applied Catalysis A: General, vol. 413-414, pp. 238–244, 2012.
View at: Publisher Site | Google Scholar
R. Djellabi, M. F. Ghorab, G. Cerrato et al., “Photoactive TiO₂-montmorillonite composite for degradation of organic dyes in water,” Journal of Photochemistry and Photobiology A: Chemistry, vol. 295, pp. 57–63, 2014.
View at: Publisher Site | Google Scholar
L. M. Martínez T, M. I. Domínguez, N. Sanabria et al., “Deposition of Al-Fe pillared bentonites and gold supported Al-Fe pillared bentonites on metallic monoliths for catalytic oxidation reactions,” Applied Catalysis A: General, vol. 364, no. 1-2, pp. 166–173, 2009.
View at: Publisher Site | Google Scholar
M. Yurdakoç, M. Akçay, Y. Tonbul, F. Ok, and K. Yurdakoç, “Preparation and characterization of Cr- and Fe-pillared bentonites by using CrCl₃, FeCl₃, Cr(acac)₃ and Fe(acac)₃ as precursors,” Microporous and Mesoporous Materials, vol. 111, no. 1–3, pp. 211–218, 2008.
View at: Publisher Site | Google Scholar
J. Chen and L. Zhu, “Comparative study of catalytic activity of different Fe-pillared bentonites in the presence of UV light and H₂O₂,” Separation and Purification Technology, vol. 67, no. 3, pp. 282–288, 2009.
View at: Publisher Site | Google Scholar
A. Eshaghi and H. Moradi, “Optical and photocatalytic properties of the Fe-doped TiO₂ nanoparticles loaded on the activated carbon,” Advanced Powder Technology, vol. 29, no. 8, pp. 1879–1885, 2018.
View at: Publisher Site | Google Scholar
G. Wei, L. Wei, Y. Chen et al., “Magnetic coupling and electric transport in Nb, Fe co-doped rutile TiO₂ epitaxial films,” Journal of Alloys and Compounds, vol. 695, pp. 2261–2265, 2017.
View at: Publisher Site | Google Scholar
X. Cao, S. Luo, C. Liu, and J. Chen, “Synthesis of bentonite-supported Fe₂O₃ -Doped TiO₂ superstructures for highly promoted photocatalytic activity and recyclability,” Advanced Powder Technology, vol. 28, no. 3, pp. 993–999, 2017.
View at: Publisher Site | Google Scholar
A. A. Isari, A. Payan, M. Fattahi, S. Jorfi, and B. Kakavandi, “Photocatalytic degradation of rhodamine B and real textile wastewater using Fe-doped TiO₂ anchored on reduced graphene oxide (Fe-TiO₂/rGO): characterization and feasibility, mechanism and pathway studies,” Applied Surface Science, vol. 462, pp. 549–564, 2018.
View at: Publisher Site | Google Scholar
B. Krishnan and S. Mahalingam, “Ag/TiO₂/bentonite nanocomposite for biological applications: synthesis, characterization, antibacterial and cytotoxic investigations,” Advanced Powder Technology, vol. 28, no. 9, pp. 2265–2280, 2017.
View at: Publisher Site | Google Scholar
T.-D. Pham and B.-K. Lee, “Selective removal of polar VOCs by novel photocatalytic activity of metals co-doped TiO₂/PU under visible light,” Chemical Engineering Journal, vol. 307, pp. 63–73, 2017.
View at: Publisher Site | Google Scholar
T.-D. Pham, B.-K. Lee, and C.-H. Lee, “The advanced removal of benzene from aerosols by photocatalytic oxidation and adsorption of Cu-TiO₂/PU under visible light irradiation,” Applied Catalysis B: Environmental, vol. 182, pp. 172–183, 2016.
View at: Publisher Site | Google Scholar
T.-D. Pham and B.-K. Lee, “Novel adsorption and photocatalytic oxidation for removal of gaseous toluene by V-doped TiO₂/PU under visible light,” Journal of Hazardous Materials, vol. 300, pp. 493–503, 2015.
View at: Publisher Site | Google Scholar
D. Kanakaraju and S. P. Wong, “Photocatalytic efficiency of TiO₂-biomass loaded mixture for wastewater treatment,” Journal of Chemistry, vol. 2018, Article ID 4314969, 14 pages, 2018.
View at: Publisher Site | Google Scholar

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Copyright © 2019 Nguyen Minh Phuong et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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