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Abstract : Clay Nanoparticles Composite Membranes Prepared with Three Different Polymers: Performance Evaluation
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Abstract: This paper presents the results obtained from the evaluation of clay nanoparticles as an additive for improving the characteristics and performance of composite membranes cast with polysulfone (PS), polyethersulfone (PES), and polyvinylidene fluoride (PVDF). Different concentrations of clay nanoparticles, ranging from 1 to 10% based on the polymer mass, were used to prepare all dope solutions. The addition of clay nanoparticles changed the internal pore morphology of membranes, which resulted in significant changes on their performance, regarding its water permeability, and fouling potential. The optimum nanoclay concentration for permeability enhancement was different for each polymer, 1.5%, 2.0%, and 6.0% for PS, PES, and PVDF, respectively. This difference can be attributed to the differences of polymer’s hydrophobicity, based on the contact angle of a sessile water drop, which is higher for PVDF (PVDF is more hydrophobic than PS and PES). The flow improvement changed based on the main polymer. Significant changes in internal pore structure were observed for all membranes. The proportion of macrovoids was decreased and pores had a better connectivity across the cross section for PES and PS membranes. For PVDF membranes, the addition of nanoclay had a different effect on their microstructure. In this case, internal pores were 20% wider, factor that increased the average membrane porosity. The simultaneous evaluation of the clay nanoparticles used as an additive have clearly demonstrated its potential application for composite membrane production. It is also worth to note that the best way for identifying and evaluating the potential for an additive for membrane casting is considering its effects for different polymers, under the same casting conditions. Keywords: Clay nanoparticles, polysulfone, polyethersulfone, PVDF, composite membranes. |
Abstract : Effect of Grit Chamber Configuration on Particle Removal: Using Response Surface Method
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Abstract: In recent years ever-increasing industrial growth has resulted in a significant increase in the production of wastewater, this wastewater sometimes contains high levels of suspended solids. Therefore, the need to formulate an appropriate course of action for managing this wastewater has reached a critical level. In this study, the removal of suspended particles in wastewater that were a byproduct of an idustrial cut stone production process were investigated. For these purposes, a laboratory grit chamber was employed, and response surface methodology (RSM) was used to simulate the contributing parameters in the settling process. In order to study the performance of the grit chamber, factors such as flow rate, inlet location and mesh size, parameters of pH, COD, BOD, TSS and turbidity in influent and effluent were monitored. Results indicated that values of pH, COD and BOD in raw wastewater were within the standard range of discharging wastewater. The results indicated that the model with a high correlation of 0.95 was able to simulate the process. In addition, turbidity removal was found to be affected by three parameters among which mesh size and its interaction with the flow rate were the most influential ones. Keywords: Grit chamber, Configuration, Response surface method, suspended solids. |
Abstract : A Simple Solution of Dissolved Ammonia Recovery Process in a Hollow-Fiber Membrane Contactor: Comparison with Experimental and Numerical Results
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Abstract: Ammonia in gaseous form is one of the major pollutants in waters and wastewaters. Of all the processes studied so far for the removal of dissolved ammonia from aqueous solution, hollow fiber membrane contactor-based processes have shown great potential. This method has shown to be effective to substantially reducing ammonia concentration to an acceptable value economically and efficiently. Mathematical analysis is presented in this report for the removal of ammonia dissolved in an aqueous phase to a recovery/stripping solution in a hollow fiber membrane contactor (HFMC). The membrane contactor is considered to consist of the lumen side (allowing aqueous flow) and shell side (allowing the flow of the stripping/recovery solution). An approximate analytical solution is derived for the simplified model that does not include radial diffusion of solutes (only axial mass flux is included). The predicted results of this solution are compared with the experimental data and with the numerical results in the literature over a range of operating conditions. The flow rates of the feed solution covered: 2.01 x 10 -9 to 4.7 x 10 -6 m3/s, initial concentration: 50 – 800 ppm and pH values of the solution containing ammonia: 8 - 11. The agreement is very good between the profiles of the simplified analytical solution and the earlier published experimental data. In addition, the results obtained by the analytical solution are close to the numerical solution of the complete model over a good range of operating conditions. Keywords: Ammonia removal, analytical solution, wastewater, hollow-fiber contactor. |
Abstract : Melamine-Ceramic Membrane for Oily Wastewater Treatment
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Abstract: Four distinctive Ceramic membranes have been synthesized using bentonite and Egyptian clay with the expansion of melamine. The addition of melamine (~ 1% by wt.) enhanced the porosity, density, the thermal stability and water permeability of the membranes made from bentonite or Egyptian clay while decreasing the chemical stability of either bentonite or Egyptian clay membranes. The most noteworthy level of decrease in COD (94.7%) is acquired for the concentration of 200ppm with saturating flux of 4.63 E-05 (m3/m2.s) utilizing (B+M) membrane. The cost of the four manufactured clay membranes was assessed based on raw materials used in the present investigation. Keywords: Oily water, emulsion, ceramic membrane, melamine. |
