Browsing by Author "AlObaid, A."

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1,3,4-Trisubstituted pyrazole bearing a 4-(chromen-2-one) thiazole: Synthesis, characterization and its biological studies
(Royal Society of Chemistry, 2015) Harikrishna, N.; Isloor, A.M.; Kulal, K.; AlObaid, A.; Fun, H.-K.
A new series 3-{2-[N?-(1,3-disubstituted-1H-pyrazol-4-yl-methylene)-hydrazino]-thiazol-4-yl}-chromen-2-one (10a-l) was synthesized by a multi-step reaction. All the synthesized compounds were characterized by IR, NMR, and mass spectral studies, followed by elemental analysis. The newly synthesized thiazole compounds were screened for their in vitro antibacterial and antifungal studies against various microorganisms. Antimicrobial studies carried out by the well diffusion method, showed a very good zone of inhibition for both bacteria (at a range of 20-50 mm diameter) and fungi (at a range of 10-30 mm diameter). Minimum Inhibitory Concentration (MIC) required for the 100% inhibition of bacteria and fungi was found to be as low as 15.6 ?g ml-1 for a few of the synthesized compounds. © The Royal Society of Chemistry 2015.
Fabrication and characterization of new PSF/PPSU UF blend membrane for heavy metal rejection
(Taylor and Francis Inc. 325 Chestnut St, Suite 800 Philadelphia PA 19106, 2016) Moideen K, I.; Isloor, A.M.; A.F., A.F.; AlObaid, A.; Fun, H.-K.
Polysulfone and polyphenylsulfone-blend ultrafiltration membranes of different compositions were prepared by the phase inversion method, with and without hydrophilic additive poly (ethylene glycol) 1,000 (PEG). The membrane morphology was studied using scanning electron microscope, which displayed the asymmetric structure of the membrane. The hydrophilicity of the membranes was measured by contact angle, porosity, water uptake, and permeability studies. The blend membrane showed enhanced permeability, hydrophilicity, and antifouling property as compared to the pristine polymer membrane. The pure water flux of the membrane, which was blended with PEG additive was relatively higher than the blend membranes without the additive. The flux recovery ratio (FRR) was measured to study the antifouling property. The membranes with PEG additive exhibited better antifouling property with maximum FRR of 72.84%. The heavy metal rejection by the membrane was carried out by complexing the metal ions with polyethyleneimine, which exhibited highest rejection of 99.48 and 95.5% of Pb2+ and Cd2+, respectively. © 2015 Balaban Desalination Publications. All rights reserved.
Preparation and performance studies of polysulfone-sulfated nano-titania (S-TiO2) nanofiltration membranes for dye removal
(Royal Society of Chemistry, 2015) Pereira, V.R.; Isloor, A.M.; Bhat, K.U.; A.F., A.F.; AlObaid, A.; Fun, H.-K.
Polysulfone nanofiltration membranes containing sulfated nano-titania (S-TiO2) were fabricated, with the aim to enhance the membrane properties along with the possible rejection of Methylene Blue (MB) dye by membranes. Initially S-TiO2 was synthesized from nano TiO2 by the action of sulfuric acid. The synthesized S-TiO2 was characterized by Fourier Transform Infrared spectroscopy (FT-IR), Energy Dispersive Spectrophotometry (EDS) and Transmission Electron Microscopy (TEM) analysis. S-TiO2 was added in increasing concentrations into the membranes and its effect on the performance of the membranes was evaluated. The synthesized membranes were characterized by Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). Polysulfone membranes containing S-TiO2 showed enhancement in properties in terms of hydrophilicity, water uptake, mechanical strength, improved pure water flux (PWF), antifouling nature and high Flux Recovery Ratio (FRR). The polysulfone membranes with S-TiO2 showed 99% rejection for BSA (Bovine Serum Albumin) protein molecules during BSA filtration. The prepared membranes were used for the removal of MB dye from aqueous solutions. A maximum of 90.4% rejection was obtained for MB for the membrane having 2.0 wt% of S-TiO2 under UV light radiation. This approach showed that polysulfone-S-TiO2 membranes displayed good efficiency for dye removal and can be effectively used for the removal of MB dye from aqueous solutions under suitable conditions. © The Royal Society of Chemistry.
Probing the morphology and anti-organic fouling behaviour of a polyetherimide membrane modified with hydrophilic organic acids as additives
(Royal Society of Chemistry, 2015) Hebbar, R.S.; Isloor, A.M.; A.F., A.F.; Shilton, S.J.; AlObaid, A.; Fun, H.-K.
A facile approach for the preparation of an organic antifouling polymer membrane has been developed using low molecular weight organic acids as additives. The presence of these additives in the membrane was analysed by FTIR spectroscopy. The properties of the modified membranes were investigated in terms of contact angle, water uptake capacity, SEM and AFM analysis. These additives exerted a strong impact on the rheological properties of the casting solution, thereby altering the membrane morphology, surface roughness, water flux and the hydrophilicity of the membranes, as compared to those of the pristine polyetherimide (PEI) membrane. The organic antifouling properties of the modified membrane were analysed by filtering both bovine serum albumin (BSA) and humic acid solutions. The results showed that the additives exhibited a remarkable improvement in the antifouling properties (FRR of 72%) and a humic acid rejection of up to 86%. These outcomes offer new insights into the use of cheaper and readily available organic acids as additives, compared to the traditional, synthetic polymer materials as additives in membrane preparation. ©2015 The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.
Synthesis, and antitubercular and antimicrobial activity of 1?-(4-chlorophenyl)pyrazole containing 3,5-disubstituted pyrazoline derivatives
(Royal Society of Chemistry, 2016) Harikrishna, N.; Isloor, A.M.; Kulal, K.; AlObaid, A.; Fun, H.-K.
A new series of 1?-(4-chlorophenyl)-5-(substituted aryl)-3?-(substituted aryl)-3,4-dihydro-2H,1?H-[3,4?]bipyrazolyl derivatives (6a-e, 8a-e, 10a-e) have been synthesized, characterized and screened for antimicrobial and antitubercular activity. Among the synthesized compounds, the minimum inhibition concentration of 10e was found to be as low as 1.56 ?g ml-1 and that of 10c was 6.25 ?g ml-1 as compared to the standard anti-tb drugs pyrazinamide and streptomycin. © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2016.