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Development of low fouling membrane using polyaniline (PAN1)-polyethersulfone (PES) blend

Razali, Nor Faizah (2015) Development of low fouling membrane using polyaniline (PAN1)-polyethersulfone (PES) blend. PhD thesis, Universiti Kebangsaan Malaysia.

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Abstract

In this present study, polyethersulfone (PES) was modified by blending with polyaniline nanoparticles (PANI) via phase inversion to produce ultrafiltration (UF) membrane with an improvement in the hydrophilic property and the performance. Polyaniline nanoparticle was synthesized via chemical oxidation in aqueous hydrochloric solution. The polyaniline nanoparticles were characterized using scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM), Xray diffi-action (XRD), Fourier transform infi-ared spectroscopy (FTIR) and Ultraviolet-visible spectroscopy (UV-Vis) analysis. The polyaniline particle size obtained was in the range of 22-50'nm and the crystalline nature of these nanoparticles was confirmed from the XRD patterns. The prepared membrane were then characterised by water permeability test, Scanning electron microscope (SEM), Atomic force microscopy (AFM), Contact angle, Zeta potential, X-ray photoelectron spectroscopy (XPS), Molecular weight cut-off (MWCO) and Tensile Strength. It was found that blended membranes have higher permeability than the controlled membrane. The decrease of static water contact angle from controlled to blended membranes (64.3" to 54.95') indicated that PANI nanoparticles has increased the surface hydrophilicity. The blended membrane showed an improvement in the membrane structure when observed by SEM. .The MWCO profiles of the prepared membranes are in the range of 22 to 35 kDa. Mechanical properties of the fabricated membranes shows that the addition of the PANI nanoparticles reduce the tensile strength of PES due to the semi-crystalline structure of PANI nanoparticles. AFM proved that the roughness of the membranes was increased with the addition of PANI nanoparticles but are significantly more hydrophilic. AFM also provide tool to calculate the membrane pore size distribution which are (1-6 nm) for controlled and - (2-40 nm) for blended membranes. Central Composite Design (CCD) of the response surface method (RSM) was used for the optimization of blended PESIPANI membranes. The optimal conditions were 18.33 wt% PES, 0.75 wt% PANI and 1.34 minutes of evaporation time with the predicted results of water permeability, salt rejection and contact angle as 62.2 L/YP~h' bar, 32.4% and 54.955 respectively. The fouling studies were conducted by tested the membranes with four different types of foulant, Bovine Serum Albumin (BSA), humic acid (HA), silica nanoparticles and E.coli and Bacillus bacteria. The fouling analysis demonstrated that the modified membranes show fewer tendencies for fouling. The modified membrane also showed high flux recovery ratio. In the rejection test, the blended membrane shows improvement in the BSA and humic acid rejection eventhough the pore size are higher than the controlled membrane. However, for silica nanoparticles, the rejection gives lower value due to the molecular shape and chemical property of silica nanoparticles. For the bacteria resistant test, the modified membrane shows less attack from the . bacteria which shows improvement in the biofouling activity. Analysis of the flux data using Hermia model suggested that complete blocking model may be the dominant fouling mechanism for the controlled membrane, whereas intermediate blocking, complete blocking and cake formation may be the major fouling mechanism for the produced and commercial membrane. In this study, both of the modified membrane shows lot of improvement in antifouling properties compared to the controlled membranes. Therefore the blended membrane offers a strong potential for possible use as a new type of anti-fouling ultrafiltration membrane.

Item Type: Thesis (PhD)
Subjects: Q Science > QD Chemistry
Depositing User: En. Sharul Ahmad
Date Deposited: 11 Apr 2016 03:59
Last Modified: 11 Apr 2016 03:59
URI: http://eprints.uthm.edu.my/id/eprint/7895
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