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Ahmad A.L.,Universiti Sains Malaysia | Ahmad A.L.,King Saud University | Abdulkarim A.A.,Universiti Sains Malaysia | Abdulkarim A.A.,Chemical and Petrochemical Research Center | And 2 more authors.
Korean Journal of Chemical Engineering | Year: 2016

The application of response surface methodology (RSM) in preparation and optimization of membranes is important in order to reduce the effort and time needed to achieving an optimum performance. RSM was used to develop an optimum polyethersulfone (PES)/ZnO mixed matrix (MM) membrane for humic acid removal. The MMs were synthesized by dispersing various amounts of hydrophilic ZnO nanoparticles (NPs) into a solution containing PES, polyvinylpyrrolidone (PVP) and dimethylacetamide (DMAc). Flat sheet MM membranes were prepared via the phase inversion method using the central composite design (CCD). The effects of four preparation parameters, such as PES, ZnO, PVP weight percentages and solvent evaporation time, were investigated. Pure water flux (PWF), humic acid flux (HAF) and humic acid rejection (HAR) were selected as a model responses. It was shown that PES and PVP were mainly affected on both PWF and HAF. Furthermore, the interaction effect between PES and ZnO-NPs shows a significant effect on PWF, while the quadratic effects of both solvent’s evaporation time and ZnO-NPs weight percentage coupled with the interaction effect between PES and PVP weight percentage shows the most significant parameters that affects HAR. The optimization method was subjected to maximize all of the PWF, HAF and HAR. It was also determined that the optimized membrane can be synthesized from a solution containing 17.25 wt% PES, 3.62 wt% ZnO and 3.75 wt% PVP with 15 s of solvent evaporation time. The optimum values of PWF, HAF and HAR were 222.3 (L/m2 h), 94.7 (L/m2 h), and 96.34%, respectively. Thus, it can be concluded that the CCD technique is capable of optimizing PES-ZnO membrane performance. © 2016 Korean Institute of Chemical Engineers, Seoul, Korea Source


Ahmad A.L.,Universiti Sains Malaysia | Abdulkarim A.A.,Universiti Sains Malaysia | Abdulkarim A.A.,Chemical and Petrochemical Research Center | Ooi B.S.,Universiti Sains Malaysia | Ismail S.,Universiti Sains Malaysia
Chemical Engineering Journal | Year: 2013

Polyethersulfone is one of the most important membrane materials and has advantageous chemical and thermal stabilities. With the inherent hydrophobic characteristics of polyethersulfone, this material may be susceptible to fouling during filtration processes. To prevent this fouling, a modification of the membrane is an indispensable step. Various modification techniques had been reported, including the use of additives, chemical treatments, grafting components, and coatings. In this article, the blending/additives modifications of polyethersulfone membranes were performed to increase the membrane flux as well as the hydrophilicity. Three types of additives were introduced, including hydrophilic, amphiphilic, and inorganic materials. The polymeric additives were compatible with good miscibility with the base material, suggesting that these materials may be useful in multiple applications. Several functional groups, such as the sulfonated, pegylated, and carboxylated groups, had excellent miscibility with the polyethersulfone, forming highly hydrophilic membranes with a resistance for protein adsorption. The amphiphilic polymers significantly improved the membrane flux, producing membranes with anti-fouling properties. Several inorganic materials were also used to increase the membrane flux, the hydrophilicity, and the mechanical properties, generating new functional membranes for defined applications. To conclude, the flux enhancement was performed by improvements in the hydrophilicity, roughness, structure, membrane thickness and surface property characteristics of the modified membranes. The blending/additive modifications allowed for improvements in the membrane permeability, the structural features and the surface properties. © 2013 Elsevier B.V. Source


Ahmad A.L.,Universiti Sains Malaysia | Abdulkarim A.A.,Universiti Sains Malaysia | Abdulkarim A.A.,Chemical and Petrochemical Research Center | Ismail S.,Universiti Sains Malaysia | Ooi B.S.,Universiti Sains Malaysia
Desalination and Water Treatment | Year: 2015

Abstract: Zinc oxide nanoparticles (ZnO-NPs) were incorporated into polyethersulfone (PES) matrix to prepare mixed matrix membranes. The separation performance of mixed matrix membranes with respect to humic acid (HA) removal was significantly improved through the addition of ZnO-NPs. The membranes were synthesised by dispersing various amounts of hydrophilic ZnO-NPs (0–3.75 wt.%) into a dope solution containing PES, polyvinylpyrrolidone (PVP) and dimethylacetamide in the appropriate proportions. SEM and AFM were employed to investigate the dispersion of the ZnO-NPs within the polymer matrix and characterise the surface properties of the particles. The pure water flux, HA flux and rejection rate, and the fouling resistance were investigated to evaluate the membrane performance. The characterisation results indicated that all of the PES/ZnO membranes possessed a smaller pore size than that of the pristine PES membrane. The HA rejection rates were observed to increase with the amount of added ZnO. In particular, the PES/ZnO membrane with 1.25 wt.% ZnO exhibited the highest pure water and HA fluxes. Additionally, the fouling analysis revealed that all of the PES/ZnO membranes exhibited a decrease in their HA fouling tendency. © 2014 Balaban Desalination Publications. All rights reserved. Source


Abdulkarim A.A.,Universiti Sains Malaysia | Abdulkarim A.A.,Chemical and Petrochemical Research Center | Ahmad A.L.,Universiti Sains Malaysia | Ismail S.,Universiti Sains Malaysia | Ooi B.S.,Universiti Sains Malaysia
Jurnal Teknologi (Sciences and Engineering) | Year: 2013

Flat sheet polyethersulfone (PES) ultrafiltration membranes were fabricated by a dry/wet induced phase inversion process. Various ranges of ZnO concentrations (from 0 -5 wt. %) were utilized in conjunction with 16.5 and 2.5 wt. % of polyethersulfone and polyvinylpyrrolidone (PVP), respectively. The prepared membranes were characterized using scanning electron microscope (SEM), contact angle (CA), and flux/rejection performance. The modified membranes were tested on humic acid removal. The hydrophilicity of PES membrane was improved after addition of zinc oxide nanoparticles in the casting solution. Highest pure water flux was obtained at 5 wt.% ZnO nanoparticles. The modified membranes with 2.5 wt. % of zinc oxide exhibited higher humic acid flux and rejection. © 2013 Penerbit UTM Press. All rights reserved. Source

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