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Photocatalytic degradation of profenofos using silver-platinum doped zeolite
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Photocatalytic degradation of profenofos using silver-platinum doped zeolite Fatin Samara, Fares Feghaly, Sofian Kanan* Department of Biology, Chemistry & Environmental Sciences, American University of Sharjah, P. O. Box 26666, Sharjah, United Arab Emirates
ARTICLE INFO
ABSTRACT
Keywords: Profenofos Photodegradation Toxicity Zeolites Silver clusters
Organophosphate insecticides are persistent organic pollutants that have a variety of adverse impacts in several environmental compartments. The photo-degradation of organophosphate profenofos was researched in the presence and absence of silver-platinum-doped zeolite in (Ag-Pt-Zeolite) upon irradiation with ultraviolet light at wavelengths of 302 and 254 nm. Photo-degradation of profenofos at 302 nm and in the presence of Ag-PtZeolite was 73 % complete in 60 min. GC/MS analysis indicated the formation of two major photo-degradation products upon irradiation with 302 nm in the presence of the catalyst. Moreover, four products were identified for the irradiation with 254 nm in the presence of the catalyst and for the uncatalyzed irradiated profenofos samples. The toxicity of the degradation products was assessed by exposure experiments using Drosophila melanogaster. These experiments showed that degradation resulted in overall less toxic products within the first 30 min of degradation, followed by an overall increase in toxicity after 30 min of UV exposure. The present work provides a treatment technique for the adequate removal of profenofos from water sources in order to mitigate its detrimental effects on the environment.
1. Introduction Since the rise of the green revolution in the 1960s, pesticides have become indispensable in conventional agricultural practices [1–6]. With a steadily growing world population, and a decrease in arable farmland used to nourish the population; innovation was necessary in the agricultural sector. The use of pesticides, fertilizers, and genetically modified crops became a feasible solution to increase food production [2]. An increase in the use of such compounds has aided in the reduction of famine occurrence, as well as a lessened dependence on environmental conditions and crop rotation [1]. Therefore, due to the success of these agricultural practices, particularly the use of pesticides, they have been further developed and extensively used in a variety of sectors including agriculture and public health, making them ubiquitous in the environment. A common class of such pesticides is known as organophosphates (OPs). A common compound belonging to the OP class of insecticides is 4-bromo-2-chloro-1-[ethoxy(propylsulfanyl) phosphoryl]oxybenzene, commonly known as profenofos (PINC-1), the structure is illustrated in Fig. 1. Profenofos is an acetylcholinesterase (AChE) inhibitor [3–6]. AChE is the enzyme responsible for the hydrolysis of acetylcholine (ACh), a widely distributed neurotransmitter in both the central and peripheral nervous systems, responsible for a diverse array of functions including ⁎
cognition and regulating motor function [3,4]. Hence, the toxicity of profenofos is derived from its inhibitory capabilities, and many intoxications have been reported particularly through occupational exposure of farmers and field workers. A common occurrence with exposure is the production of an oxidized metabolite in the human body. This metabolite is more toxic than the parent compound profenofos, which causes a permanent inactivation of AChE leading to respiratory paralysis, dimmed vision, involuntary defecation, paralysis, as well as developmental and reproductive effects [5–9]. The effect of profenofos on the environment is diverse. Since profenofos is used as an aerosolized liquid, its vapor and particulate phases will eventually be deposited back. Moreover, runoff from agricultural lands containing profenofos could contribute to its presence in both surface and groundwater sources, and it has been shown to be virtually nonvolatile from water surfaces, implying its persistence in these water bodies [10–15]. Zeolites are inorganic minerals, belonging to the tectosilicates group, with a framework of linked SiO4 and AlO4 in a tetrahedral formation that possess well defined pores and channels [16–19]. Zeolites doped with various heavy metals [19–29], have been shown to be effective in catalyzing the breakdown or degradation of organic compounds in the presence of UV radiation [30–36]. Therefore, their implementation in solid and wastewater treatment facilities as catalysts
Corresponding author. E-mail address: [email protected] (S. Kanan).
https://doi.org/10.1016/j.cattod.2019.12.024 Received 11 May 2019; Received in revised form 2 December 2019; Accepted 16 December 2019 0920-5861/ © 2019 Elsevier B.V. All rights reserved.
Please cite this article as: Fatin Samara, Fares Feghaly and Sofian Kanan, Catalysis Today, https://doi.org/10.1016/j.cattod.2019.12.024
Catalysis Today xxx (xxxx) xxx–xxx
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0.5 g of the catalyst (soild-liquid interface as heterogeneous catalysis) with aliquots being collected every 10 min for HPLC and GC–MS analyses. 3. HPLC and GC–MS measurements HPLC was used to determine the rate at which profenofos was degraded. The measurements were taken using a Shimadzu HPLC-2040C liquid chromatograph, with a photodiode array set at 216 nm as the detector. A solvent of 80 % acetonitrile and 20 % deionized water was prepared as mobile phase. 10.0 μL of the solutions were injected into the instrument. GC–MS was used to determine the degradation products. A Shimadzu QP2010 Ultra gas chromatograph-mass spectrometer equipped with a 30.0 m x0.25 mm Rtx-1 column was used in order to separate and identify the photodegradation products of profenofos. As for the GC method, the initial oven temperature was set at 60 °C and held for 2.00 min, after which it was ramped at a rate of 5 °C/minute until it reached 300 °C and then held there for 20 min. As for the mass spectrometer, the temperature was set to 230 °C. Helium was used as the carrier gas with a flow rate of 1.0 mL/min.
Fig. 1. Molecular Structure of Profenofos.
3.1. Toxicity experiment using Drosophila melanogaster
along side UV degradation at a large scale as a treatment method for a variety of organics could be an interesting idea. This application could play a major role in the removal of organophosphates such as profenofos from water sources in order to mitigate the potential environmental issues that they might pose. Herein, we aimed to synthesize silver-platinum doped zeolites as a photocatalyst for the photodegradation of profenofos using UV-radiation at 254 nm and 302 nm. In addition, the toxicity of the irradiated products will be evaluated by exposing Drosophila melanogaster.
In order to assess the toxicity of the irradiation products, Drosophila melanogaster, commonly known as the fruit flies, were exposed to profenofos. The flies used for this experiments were wild-type Drosophila reared/cultured in the laboratory. The experimental setup was prepared using instant fly media specifically tailored for the fruit fly, purchased from Carolina Biological Supply Company (Burlington, NC). Deionized water was then added to the media as per the instructions provided by the suppliers. The profenofos solution was prepared using only deionized water as solvent since organic solvents pose high toxicity to insects and might hinder the results of the exposure experiments. Samples were collected at 0, 30, and 60 min intervals of irradiation as shown in Table 1. An aliquot of 50 μL of a 160 ppm profenofos solution in deionized water was added to approximately 10 mL of the media, resulting in the final concentration of approximately 0.8 ppm. Approximately, 16 flies were selected at random, regardless of sex or age, and placed in the media containers. The flies were exposed to the compounds for a period of 7 days, after which the number of deaths was counted and recorded.
2. Materials and methodology 2.1. Reagents and sample preparation Profenofos was purchased from Sigma-Aldrich (Seelze, Germany). Ultra pure methanol and acetonitrile solvents were purchased from Scharlau (Barcelona, Spain). Pure silver nitrate and platinum (II) chloride hydrate salts were purchased from Sigma-Aldrich. In order to prepare the Ag-Pt 5 Å zeolite, 40 mL of 3.0 M AgNO3 in ammonia (Tollens reagent) were combined with acetaldehyde mixed with zeolites 5 Å and 2 mL of 1.0 M PtCl2 in a water: methanol solution. The solution was stirred for 24 h at 75 °C and then annealed at 300 °C for three hours.
4. Results and discussion A highly stable Ag-Pt-zeolite photocatalytic material was developed
2.2. Irradiation of profenofos
Table 1 Drosophila melanogaster exposure experiments.
Two solutions were prepared simultaneously in order to conduct experimentation using both high performance liquid chromatography (HPLC) and Gas Chromatography-Mass Spectrometry (GC–MS). As for the GC solution, a 160 ppm solution was prepared by dissolving 0.025 mL of the stock solution in 250 mL MeOH solution. For the HPLC analysis, a 160 ppm solution of profenofos was prepared by dissolving a volume of the stock solution in a 250 mL 1:1 methanol: water solution. For the GC/MS analysis, a 160 ppm solution was prepared by dissolving a volume of the stock solution in 250 mL of pure methanol. Two quartz test tubes with internal diameters of 12.5 mm, lengths of 10 cm, and wall thicknesses of 1 mm each were used in order to allow maximum transmittance of UV-radiation. For each of the experiments, solutions were added to the test tubes without a catalyst for initial studies. Irradiation experiments were performed using UV lamps (model UVS28) from VWR Scientific, Inc. at 254 nm and 302 nm. Each irradiation experiment was performed at a pH of 6.5 and at room temperature using a total of 5 mL of solution. The 160 ppm solutions of profenofos were irradiated in the absence and presence of
Sample Number
Sample Name
1 2 3 4 5 6
Control (No solvent or pesticide) Placebo (Only solvent, no pesticide) 0 minute exposure (160 ppm Profenofos solution) 30 minute exposure (160 ppm Profenofos solution-254 nm) 60 minute exposure (160 ppm Profenofos solution-254 nm) 30 minute exposure (160 ppm Profenofos solution-254 nm + 5A) 60 minute exposure (160 ppm Profenofos solution-254 nm + 5A) 30 minute exposure (160 ppm Profenofos solution-302 nm) 60 minute exposure (160 ppm Profenofos solution-302 nm) 30 minute exposure (160 ppm Profenofos solution-302 nm + 5A) 60 minute exposure (160 ppm Profenofos solution-302 nm + 5A)
7 8 9 10 11
5A represents the catalyst Ag-Pt 5 Å zeolite.
2
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Fig. 2. SEM image and EDX analysis for the Ag-Pt doped 5A zeolite.
and tested for possible degradation of the insecticide profenofos by ultraviolet light at 254 nm and 302 nm wavelengths. The photodegradation was monitored using HPLC every 10 min during an irradiation time of 60 min. The products of this reaction were then identified using combined GC–MS spectroscopy and the toxicity of these products as well as that of the parent compound after completion of the irradiation were assessed. The Ag and Pt metals were doped into 5 Å zeolite and characterized by using ICP, SEM-EDX, and low temperature solid-state luminescence spectroscopy. The ICP result shows the presence of 23.9 % silver and 0.5 % platinum dopants. Fig. 2 shows the SEM image of the doped catalyst. As shown in the image, the silver appears randomly distributed in the sample as a spherical morphology. Interestingly, exposing the sample to a high voltage beam of light shifted away the silver beads, as the silver dopant tends to disperse across the doped sample, thus indicating the presence of metallic silver. EDX analysis for one of the spherical shapes as identified and presented in Fig. 2 showed silver content of 43 % with a small portion of Pt that is 0.3 % as presented on the identified spherical morphology. Low temperature solid-state luminescence study shows luminescence bands that are highly dependent on the excitation wavelength. Three major luminescence bands are observed at 280–300, 310–370 nm, and at 380–420 nm and each of these bands becomes dominant over the others by selecting a characteristic excitation wavelength. It has been previously reported that both spectroscopic and theoretical data indicate the formation of metal clusters in the host zeolites sensitivity towards metal–metal interactions, where emission bands are expected from several silver centers in the zeolite framework [20–22,24,25,28,29]. Thus, the different emission bands are resolved by site-selective excitation suggesting the presence of multiple aggregations of Ag(I) ions in the zeolite host. The photocatalyzed decomposition of profenofos was carried out by irradiating two independent samples of the insecticide with UV light at 254 and 302 nm, in the presence and absence of the Ag-Pt 5 Å Zeolite catalyst. To evaluate the catalytic activity of the newly prepared catalyst under the influence of UV light, a 160 ppm solution of profenofos in methanol: water (1:1) was tested. The loss in concentration was monitored using HPLC for samples irradiated at various times. Fig. 3 shows the plot of the profenofos concentration after irradiation under different conditions. The remaining profenofos concentrations were determined from a calibration curve constructed from the HPLC peak areas that appeared at 6.79 min. As shown in Fig. 3, the degradation of profenofos under the 302 nm light source alone was slower than at 254 nm. This trend is associated to with high-energy output for irradiation at 254 nm compared to UV light at 302 nm. It is noted that in all cases, the use of the Ag-Pt- 5 Å catalyst enhances the photodegradation process compared to the corresponding uncatalyzed reactions.
Fig. 3. A plot of the degradation profiles for profenofos upon irradiation under various conditions.
HPLC profiles were recorded for the irradiated profenofos at 254 and 302 nm UV sources with and without the catalyst at 254 and 302 nm in the presence and in the absence of the catalyst. For example, Fig. 4 shows the HPLC profiles for irradiated samples under 302 nm UV light in the absence (Fig. 4a) and in the presence of the Ag-Pt 5 Å zeolite (Fig. 4b). As indicated earlier, profenofos shows HPLC signal at 6.79 min. The peak intensity was found to gradually decline upon irradiation. This reduction depends on the energy of the irradiation source along with the presence or absence of the catalyst. From the data depicted in Fig. 3, the photodegradation reaction proceeds with pseudo zero-order kinetics for the uncatalyzed reactions at 254 and 302 nm where the plot of concentration versus time was linear with good Rsquared correlation valuses as presented on Fig. 3. The photodecomposition rates of profenofos alone irradiated at 302 and 254 nm are 0.363 and 0.9498 ppm/min−1, respectively. This showed that the rate of the profenofos degradation using the higher-energy source, 254 nm UV light, is almost three times the rate observed upon the irradiation under 302 nm UV light. In addition, the photodecomposition rates of the same pesticide in the presence of the Ag-Pt 5 Å catalyst are faster than in the zeolite-free samples. Further, despite the fact that the 254 nm UV light provides higher energy than the 302 UV light, the photodecomposition rate of profenofos is the highest when the catalyzed system being irradiated at 302 nm. The increase in the catalytic strength is mainly due to the activation of large clusters upon irradiation at 302 nm, where the pronounced active catalytic sites will lead to more adsorption between the pesticide and the metal cluster sites in the zeolite host. Previous low temperature solid state studies indicate the presence of silver clusters in the doped samples [24,25,28,29]. Both reported experimental and theoretical studies indicated the activation of large size metal clusters in the zeolite host by increasing the silver loadings in the zeolite host and upon increasing the excitation 3
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Fig. 4. HPLC chromatograms recorded at 10-minute intervals for the irradiated profenofos under 302 nm UV light a) profenofos alone and b) profenofos in the presence of the Ag-Pt-5A catalyst.
wavelength [22,34,35]. The above results indicate that the catalytic activity of this system increases as the cluster size increases. Besides the observed enhancement in the photodegradation of profenofos in the presence of the catalyst, the observed products are also varied. Fig. 4 shows the HPLC charts depicted for irradiated samples under 302 nm UV light at various times with and without the catalyst. As shown in Fig. 4, the presence of the catalyst gives two major bands observed after 1.5 and 3.1 min in addition to the profenofos peak at 6.7 min. The uncatalyzed reaction shows a slight reduction in the profenofos concentration where all the products appear to be minor compared to the initial pesticide concentration. In contrast, the catalyzed and uncatalyzed reaction irradiated with 254 nm UV light shows similar products to the analogue degradation occurs at 254 without the catalyst but the relative intensities of the photodegradation products are varied (see Fig. 5a and b) GC–MS was used to identify the degradation products of profenofos (Fig. 6). After the exposure to either 254 or 302 nm UV irradiation in the absence of the catalyst, four degradation products along with remaining amount of profenofos were identified and presented in Fig. 5. Under no catalyst conditions, the starting material profenofos was recovered between 76–86 %. Similar results were identified for irradiated profenofos under 254 nm in the presence of the catalyst. In contrast, irradiation of profenofos at 302 nm in the presence of the catalyst, gave two products while only 37 % of profenofos was recovered as shown in Fig. 7. In the presence of the catalyst, the phosphate ester group of
profenofos undergoes hydrolysis that involves breaking the OeP single bond of the phosphate ester. The rate of mortality of Drosophila melanogaster was also researched in order to determine the toxicity of profenofos and its photodegraded products. The mortality rate was determined using formula 1.
Mortality Rate =
Number of Fly Deaths × 100% Total Number of Flies
(1)
Exposure experiments showed that the mortality rate of the control setup, which had the pure parent profenofos, was about 12 %, when compared to the degraded solutions. Fig. 8 shows the change in mortality rate with the change in exposure time in the presence and absence of the catalyst. As shown by Fig. 8, at 30 min of irradiation in the presence of the catalyst at 254 nm and 302 nm, a decrease in mortality was observed. Moreover, a similar trend was observed for the sample irradiated at 302 nm, without a catalyst. This result show that irradiation plays a major role in the reduction of toxicity of profenofos in the environment. On the other hand, after 60 min of 302 nm irradiation in the presence of the catalyst a different behavior was observed, showing an increase of mortality of around 71 %, compared to 0 % mortality after 30 min. These results clearly show the possibility of the formation of a product that is much more toxic than the parent compound after 60 min of irradiation. In addition, catalyzed irradiation at 254 nm and uncatalyzed irradiation at 302 nm show a similar trend, where there is a possibility of an increase in toxicity after 60 min. On the other hand,
Fig. 5. HPLC chromatograms recorded at 10-minute intervals for the irradiated profenofos under 254 nm UV light a) profenofos alone and b) profenofos in the presence of the Ag-Pt-5A catalyst. 4
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Fig. 6. Observed uncatalyzed photodegradation products of profenofos irradiated at 302 or 254 nm as well as catalyzed reaction irradiated at 254 nm.
uncatalyzed irradiation at 254 nm seems to decrease toxicity after 60 min of irradiation. The aim of this work was to minimize the adverse effects that profenofos poses to the environment. A treatment method, which exposes profenofos to 60 min of UV light at 302 nm in the presence of AgPt 5 Å zeolite, though effective in reducing its concentration, can potentially cause a greater adverse effect than profenofos itself, and thus deeming this remediation method counterproductive. Therefore, a treatment method, which utilizes Ag-Pt 5 Å zeolite and exposure to UV
light at 302 nm for 30 min, would be effective in reducing its concentration significantly as well as ensuring that the products are not harmful when released into the environment. Similar studies, have reported on the photodegradation of other pesticides such as chlorpyrifos and its pesticide formulations [37]. The authors reported that mixtures of different compounds resulted in the production of more toxic products with serious health and environmental impacts than the technical material alone. The paper concluded that caution should be used when applying UV-C irradiation to treat fruits and vegetables that were
Fig. 7. Observed degradation products of profenofos irradiated at 302 nm in the presence of the Ag-Pt-5A catalyst. 5
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References [1] [2] [3] [4] [5] [6] [7] [8]
Fig. 8. Drosophila Melanogaster mortality rate comparison among different experimental setups.
[9] [10] [11] [12]
previously exposed to the pesticide [37]. Alternatively, photodegradation at 302 nm in the presence of catalyst could be used in conjunction with other treatment methods that have been determined to be effective in the degradation of profenofos to ensure further reduction in the environmental concentration of profenofos. For instance, many studies have shown the potential that certain bacterial strains have on the biodegradation of organophosphates, including profenofos [38]. Therefore, allowing the profenofos to undergo chemical remediation first followed by biological remediation, or vice versa, could aid in ensuring that the concentrations reached by the end of the treatment process is regarded as safe to be released into the environment.
[13] [14] [15] [16] [17] [18] [19] [20] [21]
5. Conclusion
[22] [23]
The unintentional spread of the pesticide profenofos has caused a great deal of environmental pollution, therefore requiring regulatory practices and removal techniques in order to mitigate these effects. This paper aimed to develop a method for degrading profenofos to environmentally friendly compounds using inexpensive catalytic material made of Ag-Pt doped zeolite clay mineral. With the exposure to UVradiation at 302 nm for 30 min, a significant amount of profenofos was degraded by up to 35 %. Moreover, the toxicity of the degraded compounds was observed to be non-toxic as no fruit flies were killed upon exposure. This technique could also be used in conjunction with other techniques reported to degrade profenofos, in order to ensure that the concentration of profenofos entering the environment is no longer capable of causing detrimental consequences [38].
[24] [25] [26] [27] [28] [29] [30] [31] [32] [33] [34] [35]
Acknowledgements
[36] [37]
The authors of this paper would like to thank the American University of Sharjah for supporting the project (Grant # FRG17-R-16).
[38]
6
P. Pingali, Proc. Natl. Acad. Sci. 109 (2012) 12302–12308. G. Matthews, Pesticides, 2nd ed., John Wiley & Sons, Inc., New Jersey, 2015. T. Satoh, R. Gupta, Anticholinesterase Pesticides, Wiley, Hoboken, N.J, 2011. T. Südhof, K. Starke, S. Boehm, Pharmacology of Neurotransmitter Release, Springer, Berlin, 2008. L. Karalliedde, S. Feldman, J. Henry, T. Marrs, Organophosphates and Health, Imperial College Press, London, 2001. M. Eddleston, F. Worek, P. Eyer, H. Thiermann, L. Von Meyer, K. Jeganathan, M.H.R. Sheriff, A.H. Dawson, N.A. Buckley, QJM 102 (2009) 785–792. W.M. Grant, The Toxicology of the Eye, Charles C. Thomas, Springfield, Illinois, 1986. G.P. Wedin, Nephrotoxicity of anticholinesterases, in: B. Ballantyne, T.C. Marrs (Eds.), Clinical and Experimental Toxicology of Organophosphates and Carbamates, Butterworth-Heinemann, Oxford, 1992, pp. 195–202. A.B. Astroff, K.J. Freshwater, D.A. Eigenberg, Reprod. Toxicol. 12 (1998) 619–645. T. Fukuto, Environ. Health Perspect. 87 (1990) 245–254. M. Kishi, Int. J. Occup. Environ. Health 8 (2002) 175–181. Profenofos, (2018) Retrieved from https://pubchem.ncbi.nlm.nih.gov/compound/ profenofos . Retrieved on April 2019. Profenofos, (2018) Retrieved from https://toxnet.nlm.nih.gov/cgi-bin/sis/search2/ f?./temp/∼Ies3lJ:3. Retrieved on April 2019. P. Taylor, S. Camp, Z. Radic, Acetylcholinesterase, in: R. Larry, L.R. Squire (Eds.), Encyclopedia of Neuroscience, Elsevier, New York, NY, 2009, pp. 5–7. WHO, Environmental Health Criteria No 63. Organophosphorus Insecticides: A General Introduction, World Health Organization, Geneva, 1986. S. Kanan, Study of Argentate, Dicyanoargentate, and Dicyanoaurate Clusters Doped in Zeolites and the Photoassisted Degradation of NOx, Malathion, Carbofuran, and Carbaryl. Ph.D. Thesis, The Graduate School, University of Maine, 2000. V. Inglezakis, A. Zorpas, Handbook of Natural Zeolites, Bentham Science, Oak Park, Ill, 2012. H.R. Khalid, N. Lee, C. Iqra, Z. Wang, H.K. Lee, Mater. Lett. 239 (2019) 33–36. T. Tanigawa, N. Tsunoji, M. Sadakane, T. Sano, Microporous Mesoporous Mater. 277 (2019) 115–123. S. Kanan, M. Kanan, H. Patterson, J. Phys. Chem. B 105 (2001) 7508–7516. S. Kanan, F. Samara, I. Abu-Yousef, N. Abdo, D. Tobias, Res. Chem. Int. 36 (2010) 473–482. S. Kanan, I. Abu-Yousef, N. Abdo, Appl. Catal. B: Environ. 74 (2007) 130–136. M. Hong, L. Yu, Y. Wang, J. Zhang, Z. Chen, L. Dong, Q. Zan, R. Li, Chem. Eng. J. 359 (2019) 363–372. M. Kanan, S. Kanan, H. Patterson, Res. Chem. Int. 29 (2003) 691–704. S. Kanan, M. Kanan, H. Patterson, Res. Chem. Int. 32 (2006) 871–885. K. Akubo, M.A. Nahil, P. Williams, J. Energy Inst. 92 (2019) 195–202. N. Miskolczi, T. Juzsakova, J. Soja, J. Energy Inst. 92 (2019) 118–127. S. Kanan, N. Abdo, M. Khalil, X. Li, I. Abu-Yousef, F. Barilrobert, H. Patterson, Appl. Catal. B: Environ. 106 (2011) 350–358. S. Kanan, I. Abu-Yousef, N. Abdo, A. Abdel Hamid, Internat. J. of Environ. Eng. 6 (2014) 370–382. S. Kanan, F. Samara, Trends Environ. Anal. Chem. 17 (2018) 1–13. F. Samara, M. Al Shamsi, F. Kanaan, S. Kanan, Res. Chem Intermed. (2017), https:// doi.org/10.1007/s11164-017-2913-8. F. Samara, E. Jermani, S. Kanan, Arabian J. Chem. (2015), https://doi.org/10. 1016/j.arabjc.2014.12.009. S. Kanan, S. Nusri, Adv. Mat. Res. 856 (2014) 43–47. J. Ahern, S. Kanan, H. Patterson, Comments Inorg. Chem. 35 (2015) 59–81. J. Ahern, S. Kanan, Z. Sara, T. Job, R. Alnaizy, N. Abu Farha, H. Patterson, Environ. Sci. and Poll. Res. 22 (2015) 3186–3192. S. Kanan, A. Malkawi, Desalin. Water Treat. 100 (2017) 281–286. J. Savić, S. Petrović, A. Leskovac, T. Lazarević Pašti, B. Nastasijević, B. Tanović, S. Gašić, V. Vasić, Food Chem. 271 (2019) 469–478. M. Saadatullah, C. Nivedita, X. Yu, H. Zejiao, Braz. J. Microbiol. 40 (2009) 893–900.
Contents lists available at ScienceDirect
Catalysis Today journal homepage: www.elsevier.com/locate/cattod
Photocatalytic degradation of profenofos using silver-platinum doped zeolite Fatin Samara, Fares Feghaly, Sofian Kanan* Department of Biology, Chemistry & Environmental Sciences, American University of Sharjah, P. O. Box 26666, Sharjah, United Arab Emirates
ARTICLE INFO
ABSTRACT
Keywords: Profenofos Photodegradation Toxicity Zeolites Silver clusters
Organophosphate insecticides are persistent organic pollutants that have a variety of adverse impacts in several environmental compartments. The photo-degradation of organophosphate profenofos was researched in the presence and absence of silver-platinum-doped zeolite in (Ag-Pt-Zeolite) upon irradiation with ultraviolet light at wavelengths of 302 and 254 nm. Photo-degradation of profenofos at 302 nm and in the presence of Ag-PtZeolite was 73 % complete in 60 min. GC/MS analysis indicated the formation of two major photo-degradation products upon irradiation with 302 nm in the presence of the catalyst. Moreover, four products were identified for the irradiation with 254 nm in the presence of the catalyst and for the uncatalyzed irradiated profenofos samples. The toxicity of the degradation products was assessed by exposure experiments using Drosophila melanogaster. These experiments showed that degradation resulted in overall less toxic products within the first 30 min of degradation, followed by an overall increase in toxicity after 30 min of UV exposure. The present work provides a treatment technique for the adequate removal of profenofos from water sources in order to mitigate its detrimental effects on the environment.
1. Introduction Since the rise of the green revolution in the 1960s, pesticides have become indispensable in conventional agricultural practices [1–6]. With a steadily growing world population, and a decrease in arable farmland used to nourish the population; innovation was necessary in the agricultural sector. The use of pesticides, fertilizers, and genetically modified crops became a feasible solution to increase food production [2]. An increase in the use of such compounds has aided in the reduction of famine occurrence, as well as a lessened dependence on environmental conditions and crop rotation [1]. Therefore, due to the success of these agricultural practices, particularly the use of pesticides, they have been further developed and extensively used in a variety of sectors including agriculture and public health, making them ubiquitous in the environment. A common class of such pesticides is known as organophosphates (OPs). A common compound belonging to the OP class of insecticides is 4-bromo-2-chloro-1-[ethoxy(propylsulfanyl) phosphoryl]oxybenzene, commonly known as profenofos (PINC-1), the structure is illustrated in Fig. 1. Profenofos is an acetylcholinesterase (AChE) inhibitor [3–6]. AChE is the enzyme responsible for the hydrolysis of acetylcholine (ACh), a widely distributed neurotransmitter in both the central and peripheral nervous systems, responsible for a diverse array of functions including ⁎
cognition and regulating motor function [3,4]. Hence, the toxicity of profenofos is derived from its inhibitory capabilities, and many intoxications have been reported particularly through occupational exposure of farmers and field workers. A common occurrence with exposure is the production of an oxidized metabolite in the human body. This metabolite is more toxic than the parent compound profenofos, which causes a permanent inactivation of AChE leading to respiratory paralysis, dimmed vision, involuntary defecation, paralysis, as well as developmental and reproductive effects [5–9]. The effect of profenofos on the environment is diverse. Since profenofos is used as an aerosolized liquid, its vapor and particulate phases will eventually be deposited back. Moreover, runoff from agricultural lands containing profenofos could contribute to its presence in both surface and groundwater sources, and it has been shown to be virtually nonvolatile from water surfaces, implying its persistence in these water bodies [10–15]. Zeolites are inorganic minerals, belonging to the tectosilicates group, with a framework of linked SiO4 and AlO4 in a tetrahedral formation that possess well defined pores and channels [16–19]. Zeolites doped with various heavy metals [19–29], have been shown to be effective in catalyzing the breakdown or degradation of organic compounds in the presence of UV radiation [30–36]. Therefore, their implementation in solid and wastewater treatment facilities as catalysts
Corresponding author. E-mail address: [email protected] (S. Kanan).
https://doi.org/10.1016/j.cattod.2019.12.024 Received 11 May 2019; Received in revised form 2 December 2019; Accepted 16 December 2019 0920-5861/ © 2019 Elsevier B.V. All rights reserved.
Please cite this article as: Fatin Samara, Fares Feghaly and Sofian Kanan, Catalysis Today, https://doi.org/10.1016/j.cattod.2019.12.024
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0.5 g of the catalyst (soild-liquid interface as heterogeneous catalysis) with aliquots being collected every 10 min for HPLC and GC–MS analyses. 3. HPLC and GC–MS measurements HPLC was used to determine the rate at which profenofos was degraded. The measurements were taken using a Shimadzu HPLC-2040C liquid chromatograph, with a photodiode array set at 216 nm as the detector. A solvent of 80 % acetonitrile and 20 % deionized water was prepared as mobile phase. 10.0 μL of the solutions were injected into the instrument. GC–MS was used to determine the degradation products. A Shimadzu QP2010 Ultra gas chromatograph-mass spectrometer equipped with a 30.0 m x0.25 mm Rtx-1 column was used in order to separate and identify the photodegradation products of profenofos. As for the GC method, the initial oven temperature was set at 60 °C and held for 2.00 min, after which it was ramped at a rate of 5 °C/minute until it reached 300 °C and then held there for 20 min. As for the mass spectrometer, the temperature was set to 230 °C. Helium was used as the carrier gas with a flow rate of 1.0 mL/min.
Fig. 1. Molecular Structure of Profenofos.
3.1. Toxicity experiment using Drosophila melanogaster
along side UV degradation at a large scale as a treatment method for a variety of organics could be an interesting idea. This application could play a major role in the removal of organophosphates such as profenofos from water sources in order to mitigate the potential environmental issues that they might pose. Herein, we aimed to synthesize silver-platinum doped zeolites as a photocatalyst for the photodegradation of profenofos using UV-radiation at 254 nm and 302 nm. In addition, the toxicity of the irradiated products will be evaluated by exposing Drosophila melanogaster.
In order to assess the toxicity of the irradiation products, Drosophila melanogaster, commonly known as the fruit flies, were exposed to profenofos. The flies used for this experiments were wild-type Drosophila reared/cultured in the laboratory. The experimental setup was prepared using instant fly media specifically tailored for the fruit fly, purchased from Carolina Biological Supply Company (Burlington, NC). Deionized water was then added to the media as per the instructions provided by the suppliers. The profenofos solution was prepared using only deionized water as solvent since organic solvents pose high toxicity to insects and might hinder the results of the exposure experiments. Samples were collected at 0, 30, and 60 min intervals of irradiation as shown in Table 1. An aliquot of 50 μL of a 160 ppm profenofos solution in deionized water was added to approximately 10 mL of the media, resulting in the final concentration of approximately 0.8 ppm. Approximately, 16 flies were selected at random, regardless of sex or age, and placed in the media containers. The flies were exposed to the compounds for a period of 7 days, after which the number of deaths was counted and recorded.
2. Materials and methodology 2.1. Reagents and sample preparation Profenofos was purchased from Sigma-Aldrich (Seelze, Germany). Ultra pure methanol and acetonitrile solvents were purchased from Scharlau (Barcelona, Spain). Pure silver nitrate and platinum (II) chloride hydrate salts were purchased from Sigma-Aldrich. In order to prepare the Ag-Pt 5 Å zeolite, 40 mL of 3.0 M AgNO3 in ammonia (Tollens reagent) were combined with acetaldehyde mixed with zeolites 5 Å and 2 mL of 1.0 M PtCl2 in a water: methanol solution. The solution was stirred for 24 h at 75 °C and then annealed at 300 °C for three hours.
4. Results and discussion A highly stable Ag-Pt-zeolite photocatalytic material was developed
2.2. Irradiation of profenofos
Table 1 Drosophila melanogaster exposure experiments.
Two solutions were prepared simultaneously in order to conduct experimentation using both high performance liquid chromatography (HPLC) and Gas Chromatography-Mass Spectrometry (GC–MS). As for the GC solution, a 160 ppm solution was prepared by dissolving 0.025 mL of the stock solution in 250 mL MeOH solution. For the HPLC analysis, a 160 ppm solution of profenofos was prepared by dissolving a volume of the stock solution in a 250 mL 1:1 methanol: water solution. For the GC/MS analysis, a 160 ppm solution was prepared by dissolving a volume of the stock solution in 250 mL of pure methanol. Two quartz test tubes with internal diameters of 12.5 mm, lengths of 10 cm, and wall thicknesses of 1 mm each were used in order to allow maximum transmittance of UV-radiation. For each of the experiments, solutions were added to the test tubes without a catalyst for initial studies. Irradiation experiments were performed using UV lamps (model UVS28) from VWR Scientific, Inc. at 254 nm and 302 nm. Each irradiation experiment was performed at a pH of 6.5 and at room temperature using a total of 5 mL of solution. The 160 ppm solutions of profenofos were irradiated in the absence and presence of
Sample Number
Sample Name
1 2 3 4 5 6
Control (No solvent or pesticide) Placebo (Only solvent, no pesticide) 0 minute exposure (160 ppm Profenofos solution) 30 minute exposure (160 ppm Profenofos solution-254 nm) 60 minute exposure (160 ppm Profenofos solution-254 nm) 30 minute exposure (160 ppm Profenofos solution-254 nm + 5A) 60 minute exposure (160 ppm Profenofos solution-254 nm + 5A) 30 minute exposure (160 ppm Profenofos solution-302 nm) 60 minute exposure (160 ppm Profenofos solution-302 nm) 30 minute exposure (160 ppm Profenofos solution-302 nm + 5A) 60 minute exposure (160 ppm Profenofos solution-302 nm + 5A)
7 8 9 10 11
5A represents the catalyst Ag-Pt 5 Å zeolite.
2
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Fig. 2. SEM image and EDX analysis for the Ag-Pt doped 5A zeolite.
and tested for possible degradation of the insecticide profenofos by ultraviolet light at 254 nm and 302 nm wavelengths. The photodegradation was monitored using HPLC every 10 min during an irradiation time of 60 min. The products of this reaction were then identified using combined GC–MS spectroscopy and the toxicity of these products as well as that of the parent compound after completion of the irradiation were assessed. The Ag and Pt metals were doped into 5 Å zeolite and characterized by using ICP, SEM-EDX, and low temperature solid-state luminescence spectroscopy. The ICP result shows the presence of 23.9 % silver and 0.5 % platinum dopants. Fig. 2 shows the SEM image of the doped catalyst. As shown in the image, the silver appears randomly distributed in the sample as a spherical morphology. Interestingly, exposing the sample to a high voltage beam of light shifted away the silver beads, as the silver dopant tends to disperse across the doped sample, thus indicating the presence of metallic silver. EDX analysis for one of the spherical shapes as identified and presented in Fig. 2 showed silver content of 43 % with a small portion of Pt that is 0.3 % as presented on the identified spherical morphology. Low temperature solid-state luminescence study shows luminescence bands that are highly dependent on the excitation wavelength. Three major luminescence bands are observed at 280–300, 310–370 nm, and at 380–420 nm and each of these bands becomes dominant over the others by selecting a characteristic excitation wavelength. It has been previously reported that both spectroscopic and theoretical data indicate the formation of metal clusters in the host zeolites sensitivity towards metal–metal interactions, where emission bands are expected from several silver centers in the zeolite framework [20–22,24,25,28,29]. Thus, the different emission bands are resolved by site-selective excitation suggesting the presence of multiple aggregations of Ag(I) ions in the zeolite host. The photocatalyzed decomposition of profenofos was carried out by irradiating two independent samples of the insecticide with UV light at 254 and 302 nm, in the presence and absence of the Ag-Pt 5 Å Zeolite catalyst. To evaluate the catalytic activity of the newly prepared catalyst under the influence of UV light, a 160 ppm solution of profenofos in methanol: water (1:1) was tested. The loss in concentration was monitored using HPLC for samples irradiated at various times. Fig. 3 shows the plot of the profenofos concentration after irradiation under different conditions. The remaining profenofos concentrations were determined from a calibration curve constructed from the HPLC peak areas that appeared at 6.79 min. As shown in Fig. 3, the degradation of profenofos under the 302 nm light source alone was slower than at 254 nm. This trend is associated to with high-energy output for irradiation at 254 nm compared to UV light at 302 nm. It is noted that in all cases, the use of the Ag-Pt- 5 Å catalyst enhances the photodegradation process compared to the corresponding uncatalyzed reactions.
Fig. 3. A plot of the degradation profiles for profenofos upon irradiation under various conditions.
HPLC profiles were recorded for the irradiated profenofos at 254 and 302 nm UV sources with and without the catalyst at 254 and 302 nm in the presence and in the absence of the catalyst. For example, Fig. 4 shows the HPLC profiles for irradiated samples under 302 nm UV light in the absence (Fig. 4a) and in the presence of the Ag-Pt 5 Å zeolite (Fig. 4b). As indicated earlier, profenofos shows HPLC signal at 6.79 min. The peak intensity was found to gradually decline upon irradiation. This reduction depends on the energy of the irradiation source along with the presence or absence of the catalyst. From the data depicted in Fig. 3, the photodegradation reaction proceeds with pseudo zero-order kinetics for the uncatalyzed reactions at 254 and 302 nm where the plot of concentration versus time was linear with good Rsquared correlation valuses as presented on Fig. 3. The photodecomposition rates of profenofos alone irradiated at 302 and 254 nm are 0.363 and 0.9498 ppm/min−1, respectively. This showed that the rate of the profenofos degradation using the higher-energy source, 254 nm UV light, is almost three times the rate observed upon the irradiation under 302 nm UV light. In addition, the photodecomposition rates of the same pesticide in the presence of the Ag-Pt 5 Å catalyst are faster than in the zeolite-free samples. Further, despite the fact that the 254 nm UV light provides higher energy than the 302 UV light, the photodecomposition rate of profenofos is the highest when the catalyzed system being irradiated at 302 nm. The increase in the catalytic strength is mainly due to the activation of large clusters upon irradiation at 302 nm, where the pronounced active catalytic sites will lead to more adsorption between the pesticide and the metal cluster sites in the zeolite host. Previous low temperature solid state studies indicate the presence of silver clusters in the doped samples [24,25,28,29]. Both reported experimental and theoretical studies indicated the activation of large size metal clusters in the zeolite host by increasing the silver loadings in the zeolite host and upon increasing the excitation 3
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Fig. 4. HPLC chromatograms recorded at 10-minute intervals for the irradiated profenofos under 302 nm UV light a) profenofos alone and b) profenofos in the presence of the Ag-Pt-5A catalyst.
wavelength [22,34,35]. The above results indicate that the catalytic activity of this system increases as the cluster size increases. Besides the observed enhancement in the photodegradation of profenofos in the presence of the catalyst, the observed products are also varied. Fig. 4 shows the HPLC charts depicted for irradiated samples under 302 nm UV light at various times with and without the catalyst. As shown in Fig. 4, the presence of the catalyst gives two major bands observed after 1.5 and 3.1 min in addition to the profenofos peak at 6.7 min. The uncatalyzed reaction shows a slight reduction in the profenofos concentration where all the products appear to be minor compared to the initial pesticide concentration. In contrast, the catalyzed and uncatalyzed reaction irradiated with 254 nm UV light shows similar products to the analogue degradation occurs at 254 without the catalyst but the relative intensities of the photodegradation products are varied (see Fig. 5a and b) GC–MS was used to identify the degradation products of profenofos (Fig. 6). After the exposure to either 254 or 302 nm UV irradiation in the absence of the catalyst, four degradation products along with remaining amount of profenofos were identified and presented in Fig. 5. Under no catalyst conditions, the starting material profenofos was recovered between 76–86 %. Similar results were identified for irradiated profenofos under 254 nm in the presence of the catalyst. In contrast, irradiation of profenofos at 302 nm in the presence of the catalyst, gave two products while only 37 % of profenofos was recovered as shown in Fig. 7. In the presence of the catalyst, the phosphate ester group of
profenofos undergoes hydrolysis that involves breaking the OeP single bond of the phosphate ester. The rate of mortality of Drosophila melanogaster was also researched in order to determine the toxicity of profenofos and its photodegraded products. The mortality rate was determined using formula 1.
Mortality Rate =
Number of Fly Deaths × 100% Total Number of Flies
(1)
Exposure experiments showed that the mortality rate of the control setup, which had the pure parent profenofos, was about 12 %, when compared to the degraded solutions. Fig. 8 shows the change in mortality rate with the change in exposure time in the presence and absence of the catalyst. As shown by Fig. 8, at 30 min of irradiation in the presence of the catalyst at 254 nm and 302 nm, a decrease in mortality was observed. Moreover, a similar trend was observed for the sample irradiated at 302 nm, without a catalyst. This result show that irradiation plays a major role in the reduction of toxicity of profenofos in the environment. On the other hand, after 60 min of 302 nm irradiation in the presence of the catalyst a different behavior was observed, showing an increase of mortality of around 71 %, compared to 0 % mortality after 30 min. These results clearly show the possibility of the formation of a product that is much more toxic than the parent compound after 60 min of irradiation. In addition, catalyzed irradiation at 254 nm and uncatalyzed irradiation at 302 nm show a similar trend, where there is a possibility of an increase in toxicity after 60 min. On the other hand,
Fig. 5. HPLC chromatograms recorded at 10-minute intervals for the irradiated profenofos under 254 nm UV light a) profenofos alone and b) profenofos in the presence of the Ag-Pt-5A catalyst. 4
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Fig. 6. Observed uncatalyzed photodegradation products of profenofos irradiated at 302 or 254 nm as well as catalyzed reaction irradiated at 254 nm.
uncatalyzed irradiation at 254 nm seems to decrease toxicity after 60 min of irradiation. The aim of this work was to minimize the adverse effects that profenofos poses to the environment. A treatment method, which exposes profenofos to 60 min of UV light at 302 nm in the presence of AgPt 5 Å zeolite, though effective in reducing its concentration, can potentially cause a greater adverse effect than profenofos itself, and thus deeming this remediation method counterproductive. Therefore, a treatment method, which utilizes Ag-Pt 5 Å zeolite and exposure to UV
light at 302 nm for 30 min, would be effective in reducing its concentration significantly as well as ensuring that the products are not harmful when released into the environment. Similar studies, have reported on the photodegradation of other pesticides such as chlorpyrifos and its pesticide formulations [37]. The authors reported that mixtures of different compounds resulted in the production of more toxic products with serious health and environmental impacts than the technical material alone. The paper concluded that caution should be used when applying UV-C irradiation to treat fruits and vegetables that were
Fig. 7. Observed degradation products of profenofos irradiated at 302 nm in the presence of the Ag-Pt-5A catalyst. 5
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References [1] [2] [3] [4] [5] [6] [7] [8]
Fig. 8. Drosophila Melanogaster mortality rate comparison among different experimental setups.
[9] [10] [11] [12]
previously exposed to the pesticide [37]. Alternatively, photodegradation at 302 nm in the presence of catalyst could be used in conjunction with other treatment methods that have been determined to be effective in the degradation of profenofos to ensure further reduction in the environmental concentration of profenofos. For instance, many studies have shown the potential that certain bacterial strains have on the biodegradation of organophosphates, including profenofos [38]. Therefore, allowing the profenofos to undergo chemical remediation first followed by biological remediation, or vice versa, could aid in ensuring that the concentrations reached by the end of the treatment process is regarded as safe to be released into the environment.
[13] [14] [15] [16] [17] [18] [19] [20] [21]
5. Conclusion
[22] [23]
The unintentional spread of the pesticide profenofos has caused a great deal of environmental pollution, therefore requiring regulatory practices and removal techniques in order to mitigate these effects. This paper aimed to develop a method for degrading profenofos to environmentally friendly compounds using inexpensive catalytic material made of Ag-Pt doped zeolite clay mineral. With the exposure to UVradiation at 302 nm for 30 min, a significant amount of profenofos was degraded by up to 35 %. Moreover, the toxicity of the degraded compounds was observed to be non-toxic as no fruit flies were killed upon exposure. This technique could also be used in conjunction with other techniques reported to degrade profenofos, in order to ensure that the concentration of profenofos entering the environment is no longer capable of causing detrimental consequences [38].
[24] [25] [26] [27] [28] [29] [30] [31] [32] [33] [34] [35]
Acknowledgements
[36] [37]
The authors of this paper would like to thank the American University of Sharjah for supporting the project (Grant # FRG17-R-16).
[38]
6
P. Pingali, Proc. Natl. Acad. Sci. 109 (2012) 12302–12308. G. Matthews, Pesticides, 2nd ed., John Wiley & Sons, Inc., New Jersey, 2015. T. Satoh, R. Gupta, Anticholinesterase Pesticides, Wiley, Hoboken, N.J, 2011. T. Südhof, K. Starke, S. Boehm, Pharmacology of Neurotransmitter Release, Springer, Berlin, 2008. L. Karalliedde, S. Feldman, J. Henry, T. Marrs, Organophosphates and Health, Imperial College Press, London, 2001. M. Eddleston, F. Worek, P. Eyer, H. Thiermann, L. Von Meyer, K. Jeganathan, M.H.R. Sheriff, A.H. Dawson, N.A. Buckley, QJM 102 (2009) 785–792. W.M. Grant, The Toxicology of the Eye, Charles C. Thomas, Springfield, Illinois, 1986. G.P. Wedin, Nephrotoxicity of anticholinesterases, in: B. Ballantyne, T.C. Marrs (Eds.), Clinical and Experimental Toxicology of Organophosphates and Carbamates, Butterworth-Heinemann, Oxford, 1992, pp. 195–202. A.B. Astroff, K.J. Freshwater, D.A. Eigenberg, Reprod. Toxicol. 12 (1998) 619–645. T. Fukuto, Environ. Health Perspect. 87 (1990) 245–254. M. Kishi, Int. J. Occup. Environ. Health 8 (2002) 175–181. Profenofos, (2018) Retrieved from https://pubchem.ncbi.nlm.nih.gov/compound/ profenofos . Retrieved on April 2019. Profenofos, (2018) Retrieved from https://toxnet.nlm.nih.gov/cgi-bin/sis/search2/ f?./temp/∼Ies3lJ:3. Retrieved on April 2019. P. Taylor, S. Camp, Z. Radic, Acetylcholinesterase, in: R. Larry, L.R. Squire (Eds.), Encyclopedia of Neuroscience, Elsevier, New York, NY, 2009, pp. 5–7. WHO, Environmental Health Criteria No 63. Organophosphorus Insecticides: A General Introduction, World Health Organization, Geneva, 1986. S. Kanan, Study of Argentate, Dicyanoargentate, and Dicyanoaurate Clusters Doped in Zeolites and the Photoassisted Degradation of NOx, Malathion, Carbofuran, and Carbaryl. Ph.D. Thesis, The Graduate School, University of Maine, 2000. V. Inglezakis, A. Zorpas, Handbook of Natural Zeolites, Bentham Science, Oak Park, Ill, 2012. H.R. Khalid, N. Lee, C. Iqra, Z. Wang, H.K. Lee, Mater. Lett. 239 (2019) 33–36. T. Tanigawa, N. Tsunoji, M. Sadakane, T. Sano, Microporous Mesoporous Mater. 277 (2019) 115–123. S. Kanan, M. Kanan, H. Patterson, J. Phys. Chem. B 105 (2001) 7508–7516. S. Kanan, F. Samara, I. Abu-Yousef, N. Abdo, D. Tobias, Res. Chem. Int. 36 (2010) 473–482. S. Kanan, I. Abu-Yousef, N. Abdo, Appl. Catal. B: Environ. 74 (2007) 130–136. M. Hong, L. Yu, Y. Wang, J. Zhang, Z. Chen, L. Dong, Q. Zan, R. Li, Chem. Eng. J. 359 (2019) 363–372. M. Kanan, S. Kanan, H. Patterson, Res. Chem. Int. 29 (2003) 691–704. S. Kanan, M. Kanan, H. Patterson, Res. Chem. Int. 32 (2006) 871–885. K. Akubo, M.A. Nahil, P. Williams, J. Energy Inst. 92 (2019) 195–202. N. Miskolczi, T. Juzsakova, J. Soja, J. Energy Inst. 92 (2019) 118–127. S. Kanan, N. Abdo, M. Khalil, X. Li, I. Abu-Yousef, F. Barilrobert, H. Patterson, Appl. Catal. B: Environ. 106 (2011) 350–358. S. Kanan, I. Abu-Yousef, N. Abdo, A. Abdel Hamid, Internat. J. of Environ. Eng. 6 (2014) 370–382. S. Kanan, F. Samara, Trends Environ. Anal. Chem. 17 (2018) 1–13. F. Samara, M. Al Shamsi, F. Kanaan, S. Kanan, Res. Chem Intermed. (2017), https:// doi.org/10.1007/s11164-017-2913-8. F. Samara, E. Jermani, S. Kanan, Arabian J. Chem. (2015), https://doi.org/10. 1016/j.arabjc.2014.12.009. S. Kanan, S. Nusri, Adv. Mat. Res. 856 (2014) 43–47. J. Ahern, S. Kanan, H. Patterson, Comments Inorg. Chem. 35 (2015) 59–81. J. Ahern, S. Kanan, Z. Sara, T. Job, R. Alnaizy, N. Abu Farha, H. Patterson, Environ. Sci. and Poll. Res. 22 (2015) 3186–3192. S. Kanan, A. Malkawi, Desalin. Water Treat. 100 (2017) 281–286. J. Savić, S. Petrović, A. Leskovac, T. Lazarević Pašti, B. Nastasijević, B. Tanović, S. Gašić, V. Vasić, Food Chem. 271 (2019) 469–478. M. Saadatullah, C. Nivedita, X. Yu, H. Zejiao, Braz. J. Microbiol. 40 (2009) 893–900.