(Microsoft Word - 110- 117 \307\313\355\341) Study the Catalytic Activity of Degradation of Department of Chemistry (Received 6 https://doi.org/10.22153/kej.2017.09.002 Abstract The oxidative degradation of Orange G dye catalyst was prepared by precipitation method. Various physical and chemical properties of the synthesized phase. The FTIR result showed the effect of calcination temperature for CeO band intensity compared to uncalcined Ce nitrate sample. Meanwhile, the diffuse spectra at 414 nm with an energy gap of 3.2 ev. out under various conditions such as, the effects reaction. The optimum conditions for the highest decolorization efficiency (100%) were achiev G dye with catalyst dosage of 1.5 g/L, pH 2, reaction temperature of 65 °C and 0.1 mL H Keywords: Cerium oxide, Oxidation process, 1. Introduction Different shapes and sizes of semiconductor nanoparticles have been synthesized to be used in the application of advanced oxidation process Generally, as the particles size reduces to nanostructure-scale then, the properties of material will dramatically changes recent advances in synthesis of nanostructures. The particle size of materials affects their basic properties such as lattice symmetry, cell parameters, and structural characteristics [2]. The nano structure of metal oxide unique chemical properties due to their limited size and high density of corner or edge surface sites . Among different metal oxides, special attention has been focused on the formation and properties of cerium oxide is important as heterogeneous catalyst Cerium oxide that has a wide band gap is consider a good semiconducting material which is fami for its catalytic properties. Cerium, one lanthanide series exhibit both oxidation states and + 4 and has high ability for oxidation Al-Khwarizmi Engineering Journal,Vol. 13, No. 1, P.P. Catalytic Activity of CeO2 Catalyst for the Oxidative Orange G Dye in Aqueous Solution Atheel Alwash Chemistry/ Collage of Science/ AL-Nahrain University Email: atheelalwash@yahoo.com 6 June 2016; accepted 20 September 2016) https://doi.org/10.22153/kej.2017.09.002 gradation of Orange G dye by nanosized CeO2 catalyst has been performed in this study. The precipitation method. Various characterization techniques were carried out to mical properties of the synthesized catalyst. The XRD result confirms well the formation of CeO the effect of calcination temperature for CeO2 was clearly observed due to reduction in band intensity compared to uncalcined Ce nitrate sample. Meanwhile, the diffused reflection spectra recorded at 414 nm with an energy gap of 3.2 ev. The decolorization of Orange G dye by oxidation process were carried under various conditions such as, the effects of H2O2 dosage , pH, catalyst dosage and the temperature of The optimum conditions for the highest decolorization efficiency (100%) were achieved at 10 mg/L of orange of 1.5 g/L, pH 2, reaction temperature of 65 °C and 0.1 mL H2O2. Cerium oxide, Oxidation process, Nanoparticles, Heterogeneous catalyst. Different shapes and sizes of semiconductor nanoparticles have been synthesized to be used in advanced oxidation process [1]. Generally, as the particles size reduces to scale then, the properties of material will dramatically changes leading to recent advances in synthesis of nanostructures. The particle size of materials affects their basic ice symmetry, cell parameters, and structural characteristics [2]. can show unique chemical properties due to their limited size and high density of corner or edge metal oxides, special attention has been focused on the ion and properties of cerium oxide which is important as heterogeneous catalyst [3]. that has a wide band gap is consider which is familiar Cerium, one of lanthanide series exhibit both oxidation states + 3 oxidation/reduction reactions very easily. Because of this excellent property cerium oxide is used in various applications such as catalytic converters, solid oxide fuel cells and oxygen buffers Up to now various method have been developed for the synthesized of cerium oxide nanostructure, such as chemical vapor deposition, electrochemistry, templates, photoinduced conversion, biological synthesis. nanoparticles sizes of CeO2 have with different preparation method leading to produce different chemical, physical and optical properties of CeO2. The precipitation method has attracted the most attentions advantages of simple process, easy scale low cost [5]. Cerium dioxide has been taken a great interest in the application of heterogeneous photocatalytic reactions. This was due to the properties of CeO as a semiconducting material that absorbs light in the near UV and also slightly in the visible region. However, there was no report for the cerium oxide as catalyst for the degradation of organics dyes using oxidation process Khwarizmi Engineering Journal,Vol. 13, No. 1, P.P. 110- 117 (2017) Catalyst for the Oxidative Aqueous Solution catalyst has been performed in this study. The characterization techniques were carried out to study the formation of CeO2 cubic was clearly observed due to reduction in reflection spectra recorded reflection The decolorization of Orange G dye by oxidation process were carried and the temperature of ed at 10 mg/L of orange . Because of this excellent property cerium oxide is used in various such as catalytic converters, solid oxide fuel cells and oxygen buffers [4]. Up to now various method have been developed for the synthesized of cerium oxide , such as chemical vapor deposition, electrochemistry, templates, photoinduced conversion, biological synthesis. Different have been synthesized with different preparation method leading to produce different chemical, physical and optical The precipitation method has attentions owing to the ess, easy scale-up and Cerium dioxide has been taken a great interest heterogeneous photocatalytic This was due to the properties of CeO2 semiconducting material that absorbs light in the near UV and also slightly in the visible region. there was no report for the use of as catalyst for the degradation of oxidation process. As such, Al-Khwarizmi Engineering Journal Atheel Alwash Al-Khwarizmi Engineering Journal, Vol. 13, No. 1, P.P. this report have been focused on the degradation of orange G dyes using nano CeO heterogeneous catalyst using oxidation process. Different characterization techniques were conducted including characterization technique using X-ray diffraction, FTIR, diffuse reflect spectra and AFM technique. Efforts made to investigate the effects of H2O2, solution acidity and the catalyst dosage. In this study, the stability of the catalyst is excluded as the aim was on the experimental work covering thorough characterization and process study under various conditions. 2. Materials and Methods The pure metal cerium nitrate purchased from BDH. Meanwhile, hydrogen peroxide (30% analytical grade) was supplied from Analar. The sodium carbonate as a precipitating agent was purchased from Merck. The pollutant model Orange G dye was obtained from Fluka and its properties are listed in Table 1. Table 1, The structure and properties of Orange G dye Molecular structure Other names Acid Orange 10 Molecular weight 452.38 g/mol Color Index 16230 λmax 478 nm Preparation Method Pure ceria oxide has been prepared by precipitation method technique according to the method similar to Pradhan and Parida, (2010). The sodium carbonate was used as a precipitating agent at room temperature. The conce the prepared sample for pure catalyst was 0.1 M. A known volume of pure oxide was Na2CO3 of 0.25 M was added into the until the pH reached to 9. At that pH, a Khwarizmi Engineering Journal, Vol. 13, No. 1, P.P. e been focused on the degradation of orange G dyes using nano CeO2 as heterogeneous catalyst using oxidation process. Different characterization techniques were conducted including characterization technique ray diffraction, FTIR, diffuse reflectance have been the effects of adding amount of In this study, the stability of the catalyst is excluded as the aim was focusing covering thorough characterization and process study under The pure metal cerium nitrate purchased from BDH. Meanwhile, hydrogen peroxide (30% from Analar. The sodium carbonate as a precipitating agent was purchased from Merck. The pollutant model of Orange G dye was obtained from Fluka and its The structure and properties of Orange G dye. Pure ceria oxide has been prepared by precipitation method technique according to the method similar to Pradhan and Parida, (2010). The sodium carbonate was used as a precipitating agent at room temperature. The concentration of re catalyst was fixed at oxide was taken and of 0.25 M was added into the solution until the pH reached to 9. At that pH, a white precipitate solid was formed then the products were collected by filtration, washed with distilled water, and dried at 110 °C. Finally, the prepared catalyst was denoted as CeO calcination at 500 °C for 4 h. 3. Characterization Techniques The characterization of the catalyst different analytical techniques was performed on the catalyst. X-ray diffraction (XRD) was used to study the crystalline phase oxide nanoparticles. The FTIR spectroscopic analysis was carried out using Bruker Alpha spectrophotometer. Meanwhile, the spectra of the solid samples were measured using the diffrection spectrophotometer Elmer) with a wavelength range between 190 and 1,300 nm. The particle size analyzer was carried out by Brookhaven instrument. roughness of the catalyst surface was using AFM technique. Reaction Procedure and Analytical Method The experimental runs were carried out in a 250 mL conical flask as a reactor equipped with a magnetic stirrer and heater. Water containing orange G dye (10 mg/l) was transferred to the glass reactor. Thereafter, the catalyst was added to the solution. The temperature of the reaction mixture was controlled using heater to the desired value. Hydrogen peroxide was added, the runs were conducted at 60 ◦ C and the sampl taken at periodic intervals i.e. (10 min). maximum absorbance wavelength of Orange G dye was carried out using spectrophotometric analysis to determine the maximum absorption of the dye which was fixed at 478 nm. law was used to calculate the concentration of the liquid samples based on measuring the absorbance of each sample at its maximum absorbance wavelength. After a certain period of catalytic reaction, a liquid sample was withdrawn and centrifuged at 3000 rpm to separate th catalyst from liquid sample. The catalytic activity represented by the color removal was calculated based on equation (1) [7]: Decolorization Ef�iciency % � where, Cₒ is concentration of dye the concentration of dye in (mg/L) reaction time and t (min). Khwarizmi Engineering Journal, Vol. 13, No. 1, P.P. 110- 117(2017) precipitate solid was formed then the products were collected by filtration, washed several times with distilled water, and dried at 110 °C. Finally, prepared catalyst was denoted as CeO2 after its ques acterization of the catalyst with iques was performed ray diffraction (XRD) was crystalline phase of cerium The FTIR spectroscopic analysis was carried out using Bruker Alpha ter. Meanwhile, the reflection spectra of the solid samples were measured using otometer by (Perkin range between 190 and The particle size analyzer was carried out by Brookhaven instrument. The alyst surface was checked Analytical Method The experimental runs were carried out in a 250 mL conical flask as a reactor equipped with a magnetic stirrer and heater. Water containing was transferred to the glass reactor. Thereafter, the catalyst was added to the solution. The temperature of the reaction mixture was controlled using heater to the desired value. Hydrogen peroxide was added, the runs C and the samples were taken at periodic intervals i.e. (10 min). The maximum absorbance wavelength of Orange G dye was carried out using spectrophotometric to determine the maximum absorption of the dye which was fixed at 478 nm. Beer-Lambert calculate the concentration of the liquid samples based on measuring the absorbance of each sample at its maximum absorbance After a certain period of catalytic reaction, a liquid sample was withdrawn and centrifuged at 3000 rpm to separate the solid The catalytic activity represented by the color removal was calculated � � ������� � � 100 …(1) concentration of dye in (mg/L), Ct is in (mg/L) at different Atheel Alwash Al-Khwarizmi Engineering Journal, Vol. 13, No. 1, P.P. 110- 117(2017) 4. Result and Discussion 4.1. X-ray Diffraction Fig. 1 shows the indexed XRD pattern for the prepared CeO2 sample. The CeO2 show high crystalline structure of peaks that confirms the formation of cubic phase CeO2 samples. The d- spacing values of the cerium oxide sample matches well the standard code of 96-900-9009. The characteristic reflection at 2θ values were at 28.78°, 33.27°, 47.67°, 56.48°, 59.19°, 69.53° and 76.82° respectively. This result was in agreement with Chelliah et al., (2012) and Teo et al., (2014). As the Xrd result confirms the formation of cerium oxide phase this indeed improve the success of preparation method. Fig. 1. X-ray diffraction of CeO2 4.2. Fourier Transformed Infrared Spectroscopy (FTIR) Analysis The FT-IR spectrum of the CeO2 annealed at 500 °C is shown in Fig. 2 . Fig.2 (a), shows the broad absorption band located around 3429 cm –1 corresponds to the O-H stretching vibration of residual water and hydroxyl groups, while the absorption band at 1647cm –1 can be attributed to the O-H vibration in absorbed water on the sample surface. Similar results were detected with Kumara et al., (2013). The effect of calcination temperature for CeO2 was clearly observed due to reduction of those band intensity compared to uncalcined Ce nitrate sample in Fig 2 (b). In Fig. 2 (b), Chelliah et al., (2012) reported that the band at 1384 cm –1 referred to N-O stretch due to the presence of nitrate , this result confirmed our uncalcined Cerium nitrate at a band around 1362 cm –1 however this band was completely disappear after calcination due to the complete dissociation of nitrate compounds. The peaks ranging from 750 to 400 cm -1 was related to Metal-O stretching vibration [10]. The band at 844 cm –1 referred to (Ce-O) metal-oxygen bond. Fig. 2. Fourier transformed infrared spectroscopy of (a) CeO2 calcined at 500 °C (b) uncalcined cerium nitrate. 4.3. UV-vis Diffuse Reflectance Spectra Analysis and Particle Size Analyzer The diffuse reflectance spectra of CeO2 nanoparticles were recorded in Fig. 3 (a) using a UV-Vis diffuse reflectance spectra over the wavelength from 200-1200 nm. The cerium oxide nanoparticles shows a reflection spectra at 414 nm. The optical band gap energy of the prepared sample was detected in the sudden fall region at a certain wavelength. The band gap energy value was determined from the extrapolation of the straight line for the graph figured between the [Ln [(Rmax-Rmin)/(R-Rmin)]]^2 versus photon energy (hv) (as abscissa) kumar et al. (1999) as in Fig. 3 (b). Channei1 et al., (2014) reported that the energy gap of CeO2 nanoparticles was 3 ev. Khan et al., (2013) reported that the energy gap of CeO2 nanoparticles was about 4.16 ev. Meanwhile Chaiwichian et al., (2012) reported that the energy gap of CeO2 nanoparticles was 2.77 ev with particle size of 5-10 nm. The optical properties of the solid catalyst affected directly by the preparation method thus affect its energy band gap. Fig.3 (c) presents the particles size of CeO2 catalyst that was analyzed by the particle size analyzer. The result shows that the particle size of CeO2 was about 2.03 e +3 nm. According to literature, different reports have been reported the particle size of cerium oxide with different values depending on various types’ techniques such as SEM, TEM or particle size analyzer. Several factors can effects on particle size of the materials such as the preparation methods, calcination temperatures and raw materials used during the preparation methods etc…. Atheel Alwash Al-Khwarizmi Engineering Journal, Vol. 13, No. 1, P.P. 110- 117(2017) Fig. 3. UV-VIS diffuse reflectance spectra (a), band gap energy (b) and (c) particle size analyzer 4.4. Atomic Force Microscopy (AFM) Fig. 4 shows the AFM 3D image of CeO2 catalyst calcined at 500 °C. The image detects a separated conical nano columnar structure with measured roughness of (Area Ra 0.825 nm) and (Area RMS 1.03 nm). The measured roughness reported earlier for pure CeO2 thin film by Durrani et al. (2008) with (Area Ra 2.38) and (Area RMS 3.11). Fig. 4. AFM technique (3-D) image of CeO2 4.5. The Optimum Reaction Condition for the Decolorization of Orange G dye 4.5.1.Effect of pH The effect of pH on the catalytic activity of CeO2 nanoparticles for the decolorization of orange G dyes with an initial dye concentration of 10 mg/L over a pH range of 2–10. The pH of the dye solution was adjusted by adding suitable amounts of 1M HCl and NaOH. The decolorization efficiency at different pH solutions is shown in Fig. 5. The results show that the maximum decolorization efficiency of 100% was obtained at a pH of 2 after 60 min of oxidation process. At pH 5 and 10, the decolorization of Orange G dye was almost the same range about 13%. This higher catalytic activity at pH 2 was referring to the higher • OH radicals generated. Furthermore, as the orange G dye is an anionic dye, its adsorption mainly performed via an electrostatic interactions between the positive CeO2 surface and orange G dye anions, leading to a maximum extent at pH 2. Bokare et al., (2008) also reported that higher catalytic activity for orange G dye i.e. 99% was achieved at pH 2 using bimetallic nanoparticles oxide of Fe-Ni catalyst. On other hand, the lower catalytic activity at higher pH values i.e. 5 and 10 could be referred to the self-decomposition reaction of H2O2 to H2O and O2. Fig. 5. The Effect of pH on the decolorization efficiency orange G dye at initial dye concentration 10 mg/l, 0.15 g/l catalyst loading, reaction temperature 65 °C and 0.1 ml H2O2/100ml reaction volume. 4.5.2. Effect of Catalyst Dosage The effect of catalyst dosage on the decolorization efficiency of orange G dye was investigated with different catalyst dosage ranging from 0.5 g/L up to 2 g/L with reaction condition of 10 mg/L concentration of dye, 0.1ml H2O2/100ml of reaction and solution acidity of 2.0 for 60 min of reaction time as in Fig. 6. Atheel Alwash Al-Khwarizmi Engineering Journal, Vol. 13, No. 1, P.P. 110- 117(2017) Fig. 6. Effect of catalyst dosage on the decolorization efficiency orange G dye at initial dye concentration 10 mg/l, pH 2, reaction temperature 65 °C and 0.1 ml H2O2/100ml reaction volume. Before the starting of oxidation reaction, 30 min of mechanical stirring was observed until adsorption-desorption equilibrium was reached. The results showed that the adsorption rate was increase from 11% to 60% with an increase in catalyst dosage ranging from 0.5 g/L to 2 g/L, respectively. The presence of extra active sites and higher effective surface area enhance the adsorption rate in cerium oxide catalyst [17] as in Fig. 6. With the start of oxidation reaction, the catalytic activity was increased from 14% to 100% for catalysts loading of 0.05 and 1 g/l respectively. However, as the catalyst dosage was further increase up to 2 g/l, insignificant difference in catalytic activity was notice after 60 min of oxidation reaction i.e. 100%. The synergistic effect between the heterogeneous catalyst/H2O2 system enhance the generation of radicals thus, improve the catalytic activity . Slavova et al., (2014) reported that higher catalyst loading in solution would result in higher dye removal efficiency. However, the variation in optimum values of the catalyst dosage based on the process environment, the structure of dye molecules and the catalyst properties. 4.5.3. Effect of Temperature Reaction temperature is another important process parameter that has a significant effect on catalytic activity during the oxidation process. The effect of reaction temperature on the decolorization efficiency of orange G dye was detected throw a series of experiments within the catalyst loading used of 1.5 g/L, 10 mg/L initial concentration of dye, 0.1 ml H2O2/100 ml of reaction and pH of 2.0 by varying temperature from 25 °C to 65 °C as in Fig. 7. After 30 min of mechanical stirring between the nanoparticles of CeO2 and dye solution, the adsorption rate of Orange G dye was decreased as temperature increase. Mafra et al., (2013) reported that the fall in the adsorption capacity at elevated temperatures could be ascribed to the escape of the dye molecules from the catalyst surface and re-enters the liquid phase as an increase in temperature caused an increase in the speed of molecules. Consequently, as the oxidation reaction was started, the decolorization of orange G dye was significantly influenced by the reaction temperature and the decolorization was accelerated from 59% to 100% by a rise in temperature from 25 °C to 65 °C. This is because higher temperature increased the reaction rate between hydrogen peroxide and the catalyst, thus increasing the rate of generation of oxidizing species such as ˙OH radical. Fig. 7. The effect of reaction temperature on the decolorization of orange G dye under Initial dye concentration 10 mg/L, catalyst loading 1.5 g/L, pH 2 and 0.1 ml H2O2/ 100 ml of reaction volume. Effect of H2O2. The highly solubility and low volatility of hydrogen peroxide in H2O caused the excessive decomposition rate at higher temperature. Previously Muruganandham et al. (2007) reported the low bond energy of O-O bond in H2O2 solution with about (213 kJ/mol) in comparison to hydroxyl bond in water (418 kJ/mol). Consequently, the formation of radicals with the existence of hydrogen peroxide was more rapidly and considerably improved the activity of the reaction. 4.5.4. Effect of H2O2 dosage The catalytic activity based on color removal of Orange G dye was examined by changing the concentrations of hydrogen peroxide in the dye solution i.e. 0.05, 0.1 and 0.15 ml of H2O2/100 ml Atheel Alwash Al-Khwarizmi Engineering Journal, Vol. 13, No. 1, P.P. 110- 117(2017) of reaction volume within the catalyst loading used of 1.5 g/L , 10 mg/L initial concentration of dye, pH of 2.0 and reaction temperature of 65 °C as in Fig. 8. As the mechanical stirring was started, a certain amount of hydrogen peroxide was added into the reaction solution and the oxidation reaction was started. The H2O2 was consider as an external source and its addition into the reaction increase the possibility of radicals generation during the oxidation process. The optimum efficiency of 100% was found at 0.1 ml after 60 min of the reaction time as shown in Fig. 8. Above the optimum value, the decolorization efficieny of orange G dye was dropped to 50% at 0.15 ml H2O2. This reduction in catalytic activity as the amount of hydrogen peroxides increased was ascribed to its extra amount in the reaction that acts as scavengers to hydroxyl radicals [21]. Fig. 8. Effect of H2O2 addition on the decolorization of neutral red dye under several conditions. (Initial dye concentration 10 mg/L, catalyst loading 1.5 g/L, pH 5.5 and reaction temperature of 60 °C). 5. Conclusion The heterogeneous catalyst CeO2 were successfully synthesized using precipitation method. Characterization results of XRD show high crystalline structure of peaks that confirms the formation of cubic phase CeO2 samples. FTIR technique detected the effect of calcination temperature on the formation of CeO2 due to the reduction of band intensity compared to uncalcined Ce nitrate sample. The UV-Vis diffuse reflectance spectrum for CeO2 demonstrated the presence of optical band gap due to the sudden reduction in reflection spectra of the sample at 414 nm with an energy gap of 3.2 ev. Meanwhile the AFM 3D image of CeO2 calcined at 500 °C reveals the formation of well separated conical nano columnar structure with measured roughness value of 1.03 nm. A process behavior of the catalyst was also successfully elucidated. The best conditions for the highest decolorization efficiency (100%) were achieved at 10 mg/L of orange G dye, catalyst loading of 1.5 g/L, pH 2, reaction temperature of 65 °C and 0.1 mL H2O2/100 ml solution. Hence, the prepared cerium oxide catalyst under oxidation reaction is a good environmental heterogeneous catalyst and can be widely used in the application of wastewater treatment method for organic dyes in effluents. 6. References [1] Pouretedal, H.R., Kadkhodaie, A., “Synthetic CeO2 Nanoparticle Catalysis of Methylene Blue Photodegradation: Kinetics and Mechanism”, Chinese Journal of Catalysis, Vol. 31(11), (2010). [2] Zamiri, R., Ahangar, H.A., Kaushal, A., Zakaria, A., “Dielectical properties of CeO2 nanoparticles at different temperatures”, PLOS one, Vol. 10 (4), (2015). [3] Farzaneh, F. aznd Najafi, M., “Synthesis and Characterization of Cr2O3 Nanoparticles with Triethanolamine in Water under Microwave Irradiation”, Journal of Sciences, Islamic Republic of Iran, Vol. 22(4), pp.329-333, (2011). [4] Chelliah, M. Rayappan, J.B. and Krishnan, U.M., “Synthesis and Characterization of Cerium Oxide Nanoparticles by Hydroxide Mediated Approach”, Journal of Applied Science, Vol. 12 (16), pp.1734-1737, (2012). [5] LIU, Y.H., ZUO, J.C., REN, X.F., YONG, L., “Synthesis and characterization of cerium oxide (CeO2) nanoparticles by the precipitation method”, METABK, Vol. 53(4), pp.463-465, (2014). [6] Pradhan, G.K., Parida, K.M., “Fabrication of iron-cerium mixed oxide: an efficient photocatalyst for dye degradation”, International Journal of Engineering, Science and Technology, Vol. 2 (9), pp. 53-65, (2010). [7] Alwash, A. H., Abdullah , A.Z., Ismail, N., “Elucidation of Reaction Behaviors in Sonocatalytic Decolorization of Amaranth Dye in Water Using Zeolite Y Co-Incorporated with Fe and TiO2”, Advances in Chemical Engineering and Science, Vol. 3, pp.113-122, (2013). [8] Teo, S.H., Rashid, U. and Taufiq-Yap, Y, H. “Heterogeneous catalysis of transesterification of jatropha curcas oil over calcium–cerium Atheel Alwash Al-Khwarizmi Engineering Journal, Vol. 13, No. 1, P.P. 110- 117(2017) 116 bimetallic oxide catalyst”, RSC Advances, Vol. 4, pp.48836, (2014). [9] Kumara, E., Selvarajan, P., Muthuraj, D., “Synthesis and Characterization of CeO2 Nanocrystals by Solvothermal Route”, Materials Research, Vol.16(2), pp.269-276, (2013). [10] Mane, V.B., Mahind, L.H., Jadhav, K.D., Waghmode, S.A. and Dagade, S.P., “Structural Characterization of Nanosized Fe2O3-CeO2 catalysts by XRD, EDX and TEM Techniques”, Carbon – Science and Technology, Vol. 5/2, pp.260 – 264, (2013). [11] Kumar, V., Sharma, S., Sharma, T. P. and Singh, V., “Band gap determination in thick films from reflectance measurements”, Optical Materials, Vol. 12, pp.115-119, (1999). [12] Channei1, D., Inceesungvorn, B., Wetchakun, N., Ukritnukun, S., Nattestad, A., Chen, J. & Phanichphant, S., “Photocatalytic Degradation of Methyl Orange by CeO2 and Fe–doped CeO2 Films under Visible Light Irradiation”, Scientific reports, Vol. 4, pp.5757, (2014). [13] Khan, S.B., Faisal, M., Rahman, M.M., Akhtar, K., Asiri, A.M., Khan , A., Alamry, K.A., “Effect of Particle Size on the Photocatalytic Activity and Sensing Properties of CeO2 Nanoparticles”, International Journal of Electrochemical Science, Vol. 8, pp.7284 – 7297, (2013). [14] [14] Chaiwichian, S., Inceesungvorn, B., Pingmuang, K., Wetchakun, K., Phanichphant, S. and Wetchakun, N., “Synthesis and Characterization of the Novel BiVO4 /CeO2 Nanocomposites”, Engineering Journal, Vol. 16(3), (2012). [15] Durrani, S.M.A.; Al-Kuhaili, M.F.; Bakhtiari, I.A., “Carbon monoxide gas- sensing properties of electron-beam deposited cerium oxide thin films”, Sensors and Actuators B: Chemical, Vol. 134, pp.934–939, (2008). [16] Bokare, A.D., Chikate, R.C., Rode, C.V., Paknikar, K.M., “Iron-nickel bimetallic nanoparticles for reductive degradation of azo dye Orange G in aqueous solution”, Applied Catalysis B: Environmental, Vol. 79, pp.270–278, (2008). [17] Pang, Y. L. and Abdullah, A. Z., “Fe3+ doped TiO2 nanotubes for combined adsorption–sonocatalytic degradation of real textile wastewater”, Applied Catalysis B: Environmental, Vol. 129, pp.473-481, (2013). [18] Slavova, I. A., Stoyanova, M.K., Christoskova, S.G., Vanina V. Ivanova, V.V., “Study on the catalytic activity of cobalt and iron-cobalt mixed oxides for the oxidative degradation of acid orange 7 in aqueous solution”, Journal of International Scientific Publications: Ecology and Safety, Vol.8, pp.469-478, (2014). [19] Mafra, M.R., Igarashi-Mafra, L., Zuim, D.R., Vasques, E.C., and M. A. Ferreira, M.A., “Adsorption of remazol brilliant blue on an orange peel adsorbent”, Brazilian Journal of Chemical Engineering, Vol. 30 (03), pp.657 – 665, (2013). [20] Muruganandham, M., Yang, J. S. and Wu, J. J., “Effect of ultrasonic irradiation on the catalytic activity and stability of goethite catalyst in the presence of H2O2 at acidic medium”, Industrial and Engineering Chemistry Research, Vol. 46, pp.691-698, (2007). [21] Hassan, H. and Hameed, B. H., “Oxidative decolorization of Acid Red1 solutions by Fe–zeolite Y type catalyst”, Desalination, Vol. 276, pp.45-52, (2011). ا��� ���ش ��� ���� 1، ا ��د�13��� ا ��ارز � ا ������ ا ،2017( 117-110( 117 ����� ���%$� ا#ورا! ج ��ا� &���' �( ��)* � درا�� +�(ءة ا *�.,�م او+*(,� +�( ا#+*�ة أ��� ���ش �م /��� ا������ء���� ا�%$#"!/ ��� ا�&�' atheelalwash@yahoo.com ()ا�.#"- ا,��+#و: ��2� ا �د ا���#;�درا;� :���� ��819 6.7� ا,ورا(4 ج 2� ا�.01$-ف "'��م او ��"- ا�%�(�ي ط� :���� ا, �-ة 2" @A7�2BA1&ي اCوا� ��%D9 �9@ !: E�;#+ا� ����: F"#ط . G%Dا�� BA1ا�� �2%� H�IJ9 �9 ال �د ا���%���� ا��1Lت و&%$� ا��%N9 ام :-ة-I+;�2XRD ، �"رCة ا��Nا� #$P& وAFM ، H�IJ9 �ة ا���8� 2� FTIRا,وا7# ا�#ا82� I+;�2-ام PQ ;�و���س �طdiffuse reflectance spectra . S+.Tا �د ا���%���� ا��1L4 اU�+) -"�� م او��Y 9#ددات FTIR ـ4U�+) S%�2 !�W (Q ا�. (�Pح �9�"! ط�ر ا���#": BA1���� ا�1#ار"� �&���TZ9# ا�� �م او ��"-"#���� ��Uا,وا7# ا������ [N9 S)� (+\�# وا� �����2دة ا,و�� �)ر�N&ا� ��&��� )S"#+"�) م�"#�;( . 4U�+) أظ$#تdiffuse reflectance spectra د��دا :%- و'�W414nm @ة ط���PQ ار-N&3.2و ev . ����A Yءة ازا�� ا�: #L�.& #�TZ9 �$� (+ا� [:�A+�6#ات ا�+& !& -"-���&] ا����:- ا��G%D �9 درا;� ا��� H�IJ+ا� ���2�- ا;+���ل :� Sل و�`a ن [:�A+و&%$� ا� ،�c���&] ا����:- �- و7�S ا�Y . ودر'� ا�1#ارة، ��� ا���&] ا����:-، ��� ا�$�-رو'�! �2#و ��"-، در'� ا��1�و �(S ا:��A Yءة � ١٠٠ % �c��W �'ا����:- ، 2٢-ر [&���D.6@ ١٠٠/&] ھ�-رو'�! �2#و ��"- ٠.١، �+#/\�١.٥و ��� ا�� (Uا2+-ا B� #9 G& [:�A+ا� �PW !& [&١٠ j��"� ٦٥ودر'� W#ارة ، �+#�/&l& �'ل در`a٦٠ [:�A+ا� Sو� !& �Nد�� .