Investigation into the Formation of Fluidized Titanium Dioxide Porous Nanoagglomerates in a Conical Fluid Bed and Evaluating Its Physical and Mechanical Properties

Document Type : Research Article

Authors

Department of Chemical Engineering, Hamedan University of Technology, Hamedan, I.R. IRAN

Abstract

In this study, the hydrodynamic behavior of a conical fluid bed containing hydrophilic titanium oxide P25 nanoparticles and the formation of agglomerates were investigated. The particles with an initial diameter of 21 nm were fluidized by nitrogen and airflow at different superficial gas velocities. The size of the agglomerates during fluidization was determined by laser imaging and microscope electron diffraction (SEM) in the range of 40- 250 μm. According to laser images, the average size of agglomerates fluidized by nitrogen gas and airflow was 112 and 131 μm, respectively, while the average size of the complex agglomerates at the end of fluidization with nitrogen gas and airflow were 75 and 95 μm, respectively. The dynamical analysis of the bed showed that the size of the final agglomerates is highly dependent on the fluidization time. Due to the strong attractive forces between the nanoparticles, the size of the primary agglomerates was in the range of approximately 220-120 μm, which, with the continuation of fluidization, was broken down into smaller particles in the range of 145-100 μm. Young's modulus was calculated by fitting the displacement curve obtained from atomic force microscopy to 144 kPa, which corresponded to the Hertz model (141 kPa). The results indicated that increasing the gas velocity and applying airflow can partly increase the mean sphericity of particles (0.82-0.86). According to the experiments, fluidization time had a significant effect on the reduction of particle sphericity (0.58-0.75), which was affected by the failure of large agglomerates with sharp edges. The results showed that the initial agglomerates were fragile and have porosity above 80%, whereas the ultimate porosity was less than 50% with a relatively smooth surface. Unlike particle fluidization in cylindrical fluidized beds, the results of this study can help reduce particle agglomeration and achieve uniform particle size distribution.

Keywords

Main Subjects


[1] Iwadate Y., Horio M., Prediction of Agglomerate Sizes in Bubbling Fluidized Beds of Group C Powders, Powder Technology, 100(2-3): 223-226 (1998).
[2] Bika D.G., Gentzler M., Michaels J.N., Mechanical Properties of Agglomerates, Powder Technology, 117(1-2): 98-112 (2001).
[3] Rong W., Pelling A.E., Ryan A., Gimzewski J.K., Friedlander S.K., Complemen Tary Temand AFM Force Spectroscopy to Characterize the Nanomechanical Properties of Nanoparticle Chain Aggregates, Nano Letters, 4(11): 2287-2292 (2004).
[4] Ommen J.R.V., Valverde J.M., Pfeffer R., Fluidization of Nanopowders: A Review, J. Nanopart. Res., 14(737): (2012).
[5] Quevedo J.A., Omosebi A., Pfeffer R., Fluidization Enhancement of Agglomerates of Metal Oxide Nanopowders by Microjets, American Ins. Chem. Eng. (AIChE Journal), 56(6): 1456-1468 (2010).
[6] Shabanian J., Jafari R., Chaouki J., Fluidization of Ultrafine Powders, Int. Rev. Chem. Eng., 4(1): 16-50 (2012).
[7] Parveen F., Berruti F., Briens C., McMillan J., Effect of Fluidized Bed Particle Properties and Agglomerate Shape on the Stability of Agglomerates in a Fluidized Bed, Powder Technology., 237: 46-52 (2013).
[8] Khadilkar A., Rozelle P.L., Pisupati S.V., Models of Agglomerate Growth in Fluidized Bed Reactors: Critical Review, Status and Applications, Powder Technology., 264: 216-228 (2014).
[9] شیخی ا.، ستوده قره باغ ر.، مستوفی ن.، ضرغامی، ر.، محجوب جهرمی م.، تعیین مشخصه‌های هیدرودینامیکی بسترهای سیال سه ‌فازی به کمک پایش نوسان‌های ارتعاش، نشریه شیمی و مهندسی شیمی ایران، (4)43: 30 تا 53 (1390).
[10] Xiao G., Grace J.R., Lim C.J., Limestone Particle Attrition in High-Velocity Air Jets, Ind. Eng. Chem. Res., 51(1): 556-560 (2012).
[11] de Martin L., Bouwman W.G., van Ommen J.R., Multidimensional Nature of Fluidizednanoparticle Agglomerates, Langmuir, 30(42): 12696-12702 (2014).
[12] Hu D.D., Zhuang J.B., Ding M.L., A Review of Studies on the Granular Agglomeration Mechanisms and Anti Agglomeration Methods, Key Engineering Materials, 501: 515-519 (2012).
[13] Bushell G., Yan Y., Woodfield D., Raper J., Amal R., On Techniques for the Measurement of the Mass Fractaldimension of Aggregates, Adv. Colloid Interface Sci, 95(1): 1–50 (2002).
[14] de Martin L., Fabre A., van Ommen J.R., The Fractal Scaling of Fluidized Nanoparticle Agglomerates, Chem. Eng. Sci. 112: 79-86 (2014).
[15] Vicsek T., "Fractal Growth Phenomena", World Scientific Pub Co Inc, (1992).
[16] Zhou T., Li H.Z., Force Balance Modelling for Agglomerating Fluidization of Cohesive Particles, Powder Technology, 111(1-2): 60-65 (2000).
[17] Turki D., Fatah N., Behavior and Fluidization of the Cohesive Powders: Agglomerates Sizes Approach, Brazilian. J. Chem. Eng, 25(1): 697 (2008).
[18] Matsuda S., Hatano H., Muramoto T., Tsutsumi A., Modeling for Size Reduction of Agglomerates in Nanoparticle Fluidization, American Inst. Chem. Eng. (AIChE) Journal, 50(11): 2763-2771 (2004).
[19] Salameh S., Schneider J., Laube J. Alessandrini A., Facci P., Seo J.W., Colombi Ciacchi L., Mädler L., Adhesion Mechanisms of the Contactinterface of TiO2 Nanoparticles in Films and Aggregates, Langmuir, 28(31): 11457-11464 (2012).
[20] Laube J., Salameh S., Kappl M., Madler L., Ciacchi L.C., Contact Forces Between TiO2 Nanoparticles Governed by An Interplay of Adsorbed Water Layers and Roughness, Langmuir, 31(41): 11288-11295 (2015).
[21] Fabre A., Salameh S., Ciacchi L.C., Kreutzer M.T., van Ommen J.R., Contact Mechanics of Highly Porous Oxide Nanoparticle Agglomerates, Journal of Nanoparticle Research, 18: (2016).
[22] Tamadondar M.R., Zarghami R., Boutou K., Tahmasebpoor M., Mostoufi N., Size of Nanoparticle Agglomerates in Fluidization, Can. J. Chem. Eng., Wiley Online Library, 94(3): 476-484 (2016).
[23] Sokolov S. V., Kätelhön E., Compton R. G., A Thermodynamic View of Agglomeration, The Journal of Physical Chemistry C, 119(44): 25093-25099 (2015).
[24] Fabre A., “Fluidized Nanoparticle Agglomerates, Formation, Characterization, and Dynamics”,  Ph.D. Dissertation, Delft University of Technology, Delft, Netherlands, (2016).
[25] Kendall K., Alford N.M., Birchall J.D., Elasticity of Particle Assemblies as a Measure of the Surface Energy of Solids, Proceedings of the Royal Society of London A: Mathematical, Physical and Engineering Sciences, 412(1843): (1987).
[26] Kendall K., Weihs T.P., Adhesion of Nanoparticles within Spray Dried Agglomerates, Journal of Physics D: Applied Physics, 25(1A): (1992).
[27] Yoshimura H.N., Molisani A.L., Narita N.E., Cesar P.F., Goldenstein H., Porosity Dependence of Elastic Constants in Aluminum Nitride Ceramics, MaterialsResearch, 10(2): 127 (2007).
[28] Hasselman D.P.H., On the Porosity Dependence of the Elastic Moduli of Polycrystallinerefractory Materials, Journal of the American Ceramic Society banner, 45(9): 452-453 (1962).
[29] Wang J.C., Young’s Modulus of Porous Materials, Journal of Materials Science, 19(3): 801-808 (1984).
[30] Martin R.B., Haynes R.R., Confirmation of Theoretical Relation between Stiffness and Porosity in Ceramics, Journal of the American Ceramic Society, 54(8): 410-411 (1971).
[31] Phani K., Niyogi S., Elastic Modulus-Porosity Relationship for Si3N4, Journal of Materials Science Letters, 6(5): 511-515 (1987).
[32] Hertz H. Uber die Berührung fester elastischer Körper. (On the Contact of Elastic Solids). J. Reine und Angewandte Mathematik, 92(1): 156-171 (1882).
[33] Fabre A., Clemente A., BalasF., Lobera M.P., Santamaria J., Kreutzer M.T., van Ommen J.R., Modeling the Size Distribution in a Fluidized Bed of Nanopowder, J. Environ Sci: Nano., 4: 670-678 (2017).
[34] Butt H. J., Kappl M., "Surface and Interfacial Forces", John Wiley & Sons, Inc. (2010).
[35] Timoshenko S.P., Goodier J. N., "Theory of Elasticity", McGraw-Hill (1970).
[36] Tamadondar M.R., Zarghami R, Boutou K., Tahmasebpoor M., Mostoufi N., Size of Nanoparticle gglomerates in Fluidization, Can. J.Chem. Eng., 94(3): 476-484 (2016).
[37] Xi X., Kim S.H., Tittmann B., Atomic Force Microscopy based Nanoindentation Study of Onion Abaxial Epidermis Walls in Aqueous Environment, Journal of Applied Physics, 117: 024703 (2015).
[38] Bahramian A., Grace J.R., Fluidization of Titania Nanoparticle Agglomerates in a Bench Scale Conical Vessel, Powder Technology, 310: 46-59 (2017)