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Emulation results of fluid velocity for porous nanostructures...

Emulation results of fluid velocity for porous nanostructures based on Graphene Oxide (GO) and Silicon for greywater treatment applications considering the Sodium Chloride as principal solute Authors: MS. JESSICA ESTRADA DR. JOSUE LOPEZ MR. EFRAIN MEJIA CETYS UNIVERSITY Abstract: Nowadays, the correct reuse of water is an important problem around the world. Therefore, there exists a lot of research and innovation efforts to improve the water treatment conventional processes. However, these processes have many trade-offs and challenges that not allowing increase the clean water availability. On the other hand, because the chemical and physical properties of some nanomaterials and nanostructures, they can help to enhance several water treatment processes, such as desalinization, disinfection, and filtering organic and inorganic contaminants, among others. Thus, two nano-membranes based on Silicon and Graphene Oxide (GO) to filtering large size contaminants and adsorb ions, respectively, are proposed. The mentioned avoid the saturation of the GO material due to the large size contaminants and can improve the quality of purification and increase the lifetime of the nano-membranes. In this work, a PVC pipe model (width=2.5 cm and length=5 cm, see Figure 1) is used since these pipes are commonly used in domestic hydraulic installations. Also, two nano-membranes (porous media, width=0.5 cm, see Figure 1) are emulated inside the pipe. In the proposed system, four testing points were established (a,b,c and d). The test points “a” and “d” are analyzed using the Navier-Stokes equation (NS), and the Brinkman equation is applied to the other testing points (“b” and “c”) because it contemplates the porosity, viscosity dynamic and the permeability of the media. In particular, to determine the initial velocity on the entire pipe, the Manning method and Bernoulli equation were used considering a laminar flow. In particular, the fluid properties considered in order to obtain the numerical results are as follows: water density (1027 kg/m3), temperature (25 °C), viscosity (1 Pa∙s), sodium chloride concentration (5 mol/m3), initial fluid speed (0.38 m/s) and fluid pressure (249.17 Pa). In addition, the porous media properties are as follow: dynamic viscosity of GO (20.5x10-3 Pa∙s), porosity (0.44 PU), and permeability (1.86x10-8 m2). Regarding the silicon, the dynamic viscosity (2 Pa∙s), porosity (0.60 PU) and permeability (2.4 m2). A time-variant flow field was considered for the emulation. Figure 2 shows the fluid velocity on the entire pipe at t=0 seconds, which apparently it is constant in all the testing points (approx. 0.38 m/s) and adequate to the nominal fluid velocity for the chosen pipe. Figure 3 shows the fluid velocity on the entire pipe at t = 1 second, where the minimum and maximum velocity values are ≈0 m/s and ≈0.53 m/s, respectively. In addition, the arrows lines show the dynamic of the field distribution. As can be seen, the fluid velocity is increased in the nano-membranes of Silicon and Graphene Oxide, and the fluid velocity profile is modified. Finally, this work presents the mechanical analysis of a solid nanostructure based on GO and Silicon considering saltwater as fluid. As future work, a physical-chemical analysis will be required in order to determine the BET (Brunauer Emmet Teller) adsorption isotherms using the Arrhenius equation to verify the dependence of the kinetic velocity of the reaction chemistry.