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Particle Science and Technology - Volume:6 Issue: 2, Summer 2020

Journal of Particle Science and Technology
Volume:6 Issue: 2, Summer 2020

  • تاریخ انتشار: 1400/07/19
  • تعداد عناوین: 6
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  • Mohammad Imanparast, Hamed Khosravi * Pages 61-65
    This paper presents an experimental investigation using graphene nanoplatelets (GnPs) to enhance the bending performance of E-glass fiber/epoxy composites. Each specimen was prepared with two layers of E-glass chopped strand mat via the hand lay-up technique and using various contents of GnPs in the matrix (0.1, 0.2, 0.3, 0.4 and 0.5 wt%). Mechanical and ultrasonic stirring methods were employed to disperse the GnPs in the matrix. The obtained results demonstrated that the highest increases of 23% and 26% in the flexural strength and modulus, respectively, were observed for the composite containing 0.4 wt% GnPs. With the incorporation of 0.1 wt% GnPs, the flexural failure strain of the composite was enhanced by 16% compared to the control composite. The evaluation of the fractured surfaces clearly demonstrated that the interface between the glass fiber and polymeric matrix was improved when GnPs were added into the matrix.
    Keywords: Fiber-reinforced composite, Graphene nanoplatelets, Bending performance, fracture surface
  • Miralam Mahdi *, Seyed MohammadJavad Zeidi Pages 67-80

    Cavitation can be extremely beneficial for the first spray breakup and to enhance atomization quality. An Eulerian/Lagrangian approach using Reynolds average Navier-Stokes (RANS) and bubble dynamic equations was used for the prediction of cavitation inception. A comprehensive validation was also performed using the Eulerian and Lagrangian equations in the current numerical approach. First, the carrying liquid was simulated by the finite volume method in order to obtain pressure and velocity in the whole computational domain, and a one-way coupling between the Eulerian and Lagrangian parts was used. The Reynolds stress transport model (RSTM) was used for calculating turbulent parameters, and the continuous filter white noise (CFWN) model was used for modeling fluctuating terms of velocity. Rayleigh-Plesset and a modified form of the bubble motion equation were also applied to study the bubble dynamic and bubble position inside the nozzle. A modified form of critical pressure was also used to evaluate critical pressure as cavitation starts and showed critical pressure increases significantly as cavitation starts. The bubble shock wave due to the first and second bubble collapse was predicted in the cavitating and non-cavitating flow. A shock wave due to the bubble’s first collapse in cavitation inception conditions increased to 28 Mpa. Results showed that increasing the pressure difference can severely increase the shockwave while increasing the initial radius will decrease the amount of the emitted shockwave. Effects of surface tension, dynamic viscosity, and liquid density on bubble dynamic were evaluated.

    Keywords: Cavitation, Shockwave, Eulerian, Lagrangian approach, Nozzle
  • Vahid Vahidfard, Keivan Shayesteh *, Pourya Abbasi, Mehdi Hosseini Pages 81-93
    Cadmium is one of the impurities to be removed from the electrolyte solution before zinc electrowinning. Removal of cadmium by cementation with zinc powder is diffusion-controlled. This study analyzed the parameters that effective the removal of cadmium by zinc powder from the point of view of molecular diffusion. Studies have shown that parameter changes can be easily justified by this mechanism, and a logical connection is raised between the theoretical issues and what is happening in reality.
    Keywords: Removal of cadmium, Central Composite Design, Zinc sulfate solution, diffusion, cementation
  • Mohsen Samimi *, Sepideh Moeini Pages 95-102
    Biocompatible materials, as efficient sorbent, are used for the removal of dyes and heavy metals ions from water and industrial wastewater. In this work, the optimal conditions for the maximum barium uptake in the formation process of Ba-alginate beads (Ba-ALG) were determined using the central composite design (CCD). The operational factors were evaluated for polymer/barium ratios of 1:3, 1:2, 1:1, 2:1, and 3:1 and residence times of 20, 30, 75, 120, and 180 minutes. The optimal ratio of sodium alginate to barium concentration for cations uptake was obtained at 3:1. Ba-ALG could not form a spherical and stable structure at higher polymer/cross-linker ratios. Validation tests illustrated the high accuracy of the selected model to determine the optimal experimental conditions in the barium uptake process. The maximum barium uptake is 88.61%, which was achieved at XAB =1.5 (optimal ratio of polymer to Ba+2) and Xt =1.5 (180 min). The ability of Ba-ALG to adsorb dye was also evaluated. Kinetics, equilibrium, and thermodynamic studies for adsorption of malachite green (MG) by Ba-ALG were statistically described. The adsorption results match the pseudo-second-order kinetics, suggesting that there was MG dye uptake to the adsorbent in monolayers due to its chemical affinity. The thermodynamic parameters were also determined by the Gibbs free energy function, confirming that the adsorption process was spontaneous and accompanied by an endothermic reaction.
    Keywords: Barium alginate, ionotropic gelation, CCD, adsorption kinetics, thermodynamic parameters
  • Behnaz Sarani, Mashaallah Rahmani *, AhmadReza Abbasian Pages 103-111

    In this study, we present a new combustion method for the preparation of meso-adsorbent NiFe2O4 powders. SEM, XRD, and BET were used for the characterization of adsorbents. BET measurements confirmed a specific surface area (SSA) of 87.7 m2.g-1, a total pore volume (PV) of 0.2377 cm3.g-1, and a mean pore size (PS) of 10.841 nm. The mean crystallite diameter of the adsorbent using the Scherrer equation was 10 nm. Also, the response surface methodology and artificial neural network models were used for modeling, optimization, and prediction of responses for removing methyl violet from water and wastewater in lab-scale batches. To study absorption, a four-factor central composite design was used to select the best experimental condition for ultrasonic-assisted adsorption of methyl violet dye. The adjusted R2 of 0.9931 and the predicted R2 of 0.9813 are very close, indicating the compatibility of the experimental results with the quadratic model. According to the results, optimum conditions were set at an ultrasonic time of 231 s, 13.5 mg of adsorbent, a dye concentration of 2.0 mg.L-1, and a pH = 7.9. Also, the learning rule of Levenberg–Marquardt was used for ANN Modeling. According to the proposed ANN, the value of the root mean square error (RMSE) was 2.562, and the value of the correlation coefficient (R2) was 0.986. Also, removal efficiencies of 96.8% and 95.57% were obtained for the tap water and wastewater, respectively.

    Keywords: NiFe2O4 Meso-adsorbent, Ultrasonic assisted adsorption, Water, wastewater
  • Masoud Rafigh Esmaeilzaei, Hamideh Saravani, AhmadReza Abbasian Pages 113-122

    ZnFe2O4-ZnS adsorbent was synthesized by the single-stage solution combustion procedure applying the thiourea at different fuel to oxidant ratios (ϕ = 1, 1.2, 1.4, and 1.6), and different Zn to Fe molar ratios (Zn : Fe = 0.5, 0.6, 0.7, and 0.8). The efficiency of the removal of methyl orange dye by synthesized powders in various conditions was investigated. The best sample, in terms of dye removal, was the synthesized powder at Zn : Fe = 0.6 and ϕ = 1.4. Dye removal was discovered to be extremely pH-dependent. The highest dye removal was observed to be about 94% of methyl orange, which disappears after 20 min in a dark environment. Kinetics investigations were carried out to discover the mechanism of methyl orange elimination and its adsorption rate kinetics. It was found that the elimination of methyl orange by ZnFe2O4-ZnS powders follows a pseudo second-order adsorption kinetics model.

    Keywords: Combustion synthesis, Thiourea fuel, Dye removal, Kinetics model