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Papers by Badriya Al-Rashdi

Journal of Membrane Science, Feb 1, 2012

The atomic force microscope (AFM) has become a useful tool for studying the morphology of membran... more The atomic force microscope (AFM) has become a useful tool for studying the morphology of membrane surfaces as well as their fouling characteristics. One principle advantage of the AFM over other high resolution imaging techniques is the ability to make observations in both ambient air and liquid environments. Diverse imaging modes also exist, each with their own advantages and disadvantages. In this study two different imaging modes in both air and water are compared when examining two different nanofiltration membranes, to compare the strengths and weakness of different methods of obtaining surface topography when applied to nanofiltration membrane characterization. When imaging the more hydrophobic of the two membranes using tapping mode in a water environment features consistent with the existence of surface adhered nanobubbles were observed. Such features have implications for the fouling of membranes by hydrophobic materials, as well as effects on the ability to image hydrophobic membrane surfaces under such conditions.

Separation & Purification Reviews, 2011

... Figure 1 illustrates these mechanisms. For removal of cadmium, various adsorbents were used a... more ... Figure 1 illustrates these mechanisms. For removal of cadmium, various adsorbents were used and some of these were summarised by Balkaya and Cesur (8) and Ngah and Hanafiah (3), together with their adsorption capacities. Sorbents from plants. ...

Journal of Membrane Science, 2012

Desalination, Apr 1, 2013

This study describes the rejection of heavy metal ions using a commercial nanofiltration membrane... more This study describes the rejection of heavy metal ions using a commercial nanofiltration membrane (NF270). The effect of feed pH, pressure and metal concentration on the metal rejections and permeate flux and in some cases permeate pH was explored. The results showed that with all metals examined (except As (III)), when the feed pH is below the isoelectric point, the rejection increased. NF270 rejected almost 100% of copper ions at low concentrations, but decreased to 58% at the highest concentration examined. Using 1000 mg/L concentration level, pH = 1.5 ± 0.2 and 4 bar the rejection was 99%, 89% and 74% for cadmium, manganese and lead respectively. However at pH above the isoelectric point the average rejections decreased. NF270 was unable to retain As(III). The metals caused a flux decline due to membrane fouling in the order of severity: Cu 2+ > Cd 2+ ≈ Mn 2+ > Pb 2+ ≈ As 3+. The correlation between adsorbed amounts of the metals onto NF270 with the normalised flux shows that as the amount increased the normalised flux decreased, except for arsenic that had a higher deposited amount and higher flux. The RMS roughness as obtained by AFM showed that roughness was decreased by membrane fouling.

Chemical Engineering Journal, 2012

Diboron trioxide/titanium dioxide (B 2 O 3 /TiO 2) was synthesised at the nano-size and used to r... more Diboron trioxide/titanium dioxide (B 2 O 3 /TiO 2) was synthesised at the nano-size and used to remove Cu(II) from water by adsorption. The material was characterised using a number of techniques including XRD, SEM, TEM, and BET surface area. Sizes of the material were below 50 nm, which fall within the range of that of nanoparticles. The BET surface area was 222.4 ± 6.8 m 2 /g. B 2 O 3 /TiO 2 was effective in removing copper and the maximum adsorption capacity was 82.0 mg/g. The equilibrium adsorption data were best fitted to Freundlich model and the adsorption kinetics was well explained by pseudo-second-order kinetic model, which suggests that the copper uptake is due to a chemisorption process. An intraparticle diffusion based Weber-Morris model was applied to evaluate the rate-limiting steps, and the results suggested that pore diffusion controlled the overall sorption process.

Journal of Membrane Science, Feb 1, 2012

The atomic force microscope (AFM) has become a useful tool for studying the morphology of membran... more The atomic force microscope (AFM) has become a useful tool for studying the morphology of membrane surfaces as well as their fouling characteristics. One principle advantage of the AFM over other high resolution imaging techniques is the ability to make observations in both ambient air and liquid environments. Diverse imaging modes also exist, each with their own advantages and disadvantages. In this study two different imaging modes in both air and water are compared when examining two different nanofiltration membranes, to compare the strengths and weakness of different methods of obtaining surface topography when applied to nanofiltration membrane characterization. When imaging the more hydrophobic of the two membranes using tapping mode in a water environment features consistent with the existence of surface adhered nanobubbles were observed. Such features have implications for the fouling of membranes by hydrophobic materials, as well as effects on the ability to image hydrophobic membrane surfaces under such conditions.

Separation & Purification Reviews, 2011

... Figure 1 illustrates these mechanisms. For removal of cadmium, various adsorbents were used a... more ... Figure 1 illustrates these mechanisms. For removal of cadmium, various adsorbents were used and some of these were summarised by Balkaya and Cesur (8) and Ngah and Hanafiah (3), together with their adsorption capacities. Sorbents from plants. ...

Journal of Membrane Science, 2012

Desalination, Apr 1, 2013

This study describes the rejection of heavy metal ions using a commercial nanofiltration membrane... more This study describes the rejection of heavy metal ions using a commercial nanofiltration membrane (NF270). The effect of feed pH, pressure and metal concentration on the metal rejections and permeate flux and in some cases permeate pH was explored. The results showed that with all metals examined (except As (III)), when the feed pH is below the isoelectric point, the rejection increased. NF270 rejected almost 100% of copper ions at low concentrations, but decreased to 58% at the highest concentration examined. Using 1000 mg/L concentration level, pH = 1.5 ± 0.2 and 4 bar the rejection was 99%, 89% and 74% for cadmium, manganese and lead respectively. However at pH above the isoelectric point the average rejections decreased. NF270 was unable to retain As(III). The metals caused a flux decline due to membrane fouling in the order of severity: Cu 2+ > Cd 2+ ≈ Mn 2+ > Pb 2+ ≈ As 3+. The correlation between adsorbed amounts of the metals onto NF270 with the normalised flux shows that as the amount increased the normalised flux decreased, except for arsenic that had a higher deposited amount and higher flux. The RMS roughness as obtained by AFM showed that roughness was decreased by membrane fouling.

Chemical Engineering Journal, 2012

Diboron trioxide/titanium dioxide (B 2 O 3 /TiO 2) was synthesised at the nano-size and used to r... more Diboron trioxide/titanium dioxide (B 2 O 3 /TiO 2) was synthesised at the nano-size and used to remove Cu(II) from water by adsorption. The material was characterised using a number of techniques including XRD, SEM, TEM, and BET surface area. Sizes of the material were below 50 nm, which fall within the range of that of nanoparticles. The BET surface area was 222.4 ± 6.8 m 2 /g. B 2 O 3 /TiO 2 was effective in removing copper and the maximum adsorption capacity was 82.0 mg/g. The equilibrium adsorption data were best fitted to Freundlich model and the adsorption kinetics was well explained by pseudo-second-order kinetic model, which suggests that the copper uptake is due to a chemisorption process. An intraparticle diffusion based Weber-Morris model was applied to evaluate the rate-limiting steps, and the results suggested that pore diffusion controlled the overall sorption process.