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Full-Text Articles in Nanoscience and Nanotechnology

Zeolite Linde Type L As Micro-Solid Phase Extraction Sorbent For The High Performance Liquid Chromatography Determination Of Ochratoxin A In Coffee And Cereal, Eng-Poh Ng Dr. Jan 2012

Zeolite Linde Type L As Micro-Solid Phase Extraction Sorbent For The High Performance Liquid Chromatography Determination Of Ochratoxin A In Coffee And Cereal, Eng-Poh Ng Dr.

Eng-Poh Ng

Zeolite Linde Type L (LTL) crystals with different length, diameter and particle size (nanosized LTL, rod LTL, cylinder LTL and needle LTL) were synthesized, characterized and were used as sorbent in the micro-solid phase extraction of ochratoxin A (OTA) before the high performance liquid chromatography detection. Under the optimized conditions, the detection limits of OTA for coffee and cereal were 0.09 ng g−1 and 0.03 ng g−1, respectively, while the quantification limits were 0.28 ng g−1 and 0.08 ng g−1, respectively. The recoveries of OTA of coffee and cereal spiked at 0.5, 10 and 25 ng g−1 ranged from 91.7 …


Capturing Ultrasmall Emt Zeolite From Template-Free Systems, Eng-Poh Ng Dr. Jan 2012

Capturing Ultrasmall Emt Zeolite From Template-Free Systems, Eng-Poh Ng Dr.

Eng-Poh Ng

No abstract provided.


Nanosized Molecular Sieves Utilized As An Environmentally Friendly Alternative To Antioxidants For Lubricant Oils, Eng-Poh Ng Dr. Jan 2011

Nanosized Molecular Sieves Utilized As An Environmentally Friendly Alternative To Antioxidants For Lubricant Oils, Eng-Poh Ng Dr.

Eng-Poh Ng

Lubricants play a significant part in current environmental considerations since they are an integral and indispensable component of modern technology. The production, application and disposal of the lubricants have to follow increasingly strict requirements for protecting the environment and living organisms. In this respect, molecular sieve (LTL type zeolite) is investigated as a potential environmentally friendly alternative to traditional antioxidant additives for lubricant oils. Accelerated oxidation experiments using pure base oil and additivated base oil in the presence of the LTL molecular sieve are carried out in parallel, and the oxidation processes are monitored by FT-IR spectroscopy, spectrophotometry, chromatography, total …


Micro- To Macroscopic Observations Of Mnalpo-5 Nanocrystal Growth In Ionic-Liquid Media, Eng-Poh Ng Dr. Jan 2010

Micro- To Macroscopic Observations Of Mnalpo-5 Nanocrystal Growth In Ionic-Liquid Media, Eng-Poh Ng Dr.

Eng-Poh Ng

Micro- and macroscopic studies of nucleation and growth processes of MnAlPO-5 nanosized crystals under ionothermal synthesis conditions are reported herein. The samples treated at 150 8C were extracted from the reaction mixture at various stages of crystallization, and characterized by XRD; SEM; thermogravimetric analysis (TGA); 31P and 27Al solid-state magic angle spinning (MAS) NMR, Raman, UV/Vis, and X-ray fluorescence spectroscopy (XRF). The starting raw materials (alumina, manganese, and phosphorous) were dissolved completely in the ionic liquid and transformed into an amorphous solid after 5 h of ionothermal treatment. This amorphous solid then undergoes structural changes over the following 5–25 h, …


Optical Properties Of Photopolymer Layers Doped With Aluminophosphate Nanocrystals, Eng-Poh Ng Dr. Jan 2010

Optical Properties Of Photopolymer Layers Doped With Aluminophosphate Nanocrystals, Eng-Poh Ng Dr.

Eng-Poh Ng

The optical properties of photopolymer layers consisting of an acrylamide-based matrix and microporous aluminophosphate nanocrystals of AEI type are investigated. The compatibility of the photopolymer doped with the nanoparticles is studied. The surface and volume properties of the layers with different levels of doping with microporous nanocrystals are characterized. The effective refractive indices and absorption coefficients of the doped photopolymer layers are determined and used to calculate the refractive index and porosity of pure AEI nanoparticles used as dopants. Volume transmission gratings were recorded in the doped photopolymer layers at different spatial frequencies. By spatial monitoring of the characteristic Raman …


Discrete Mnalpo-5 Nanocrystals Synthesized By An Ionothermal Approach, Eng-Poh Ng, Satpal Singh Sekhon, Svetlana Mintova Jan 2009

Discrete Mnalpo-5 Nanocrystals Synthesized By An Ionothermal Approach, Eng-Poh Ng, Satpal Singh Sekhon, Svetlana Mintova

Eng-Poh Ng

Discrete MnAlPO-5 nanocrystals with monomodal particle size distribution (diameter of 80 nm) were synthesized using an ionothermal technique; the pore filling effect of the ionic liquid molecules during the synthesis of microporous nanocrystals is verified.


Selective Capture Of Water Using Microporous Adsorbents To Increase The Lifetime Of Lubricants, Eng-Poh Ng, Luc Delmotte, Svetlana Mintova Jan 2009

Selective Capture Of Water Using Microporous Adsorbents To Increase The Lifetime Of Lubricants, Eng-Poh Ng, Luc Delmotte, Svetlana Mintova

Eng-Poh Ng

Eco-recycling towards an increase of the lifetime of lubricating mineral oil by selective capturing of water with nanosized microporous aluminophosphate and aluminosilicate materials is reported. Quantitative water measurements of oxidized lubricating oil before and after treatment with microporous materials were carried out by FT-IR spectroscopy combined with Karl Fischer titration method. The high selectivity of the nanosized aluminophosphate to water without adsorbing other additives in comparison to nanosized aluminosilicates that are adsorbing altogether polar oxidation products, ionic additives and water are revealed. A removal of nearly 98 % of moisture from the lubricating oil at ambient condition is achieved, which …


Nanoporous Materials With Enhanced Hydrophilicity And High Water Capacity, Eng-Poh Ng, Svetlana Mintova Sep 2008

Nanoporous Materials With Enhanced Hydrophilicity And High Water Capacity, Eng-Poh Ng, Svetlana Mintova

Eng-Poh Ng

The main types of nanoporous adsorbents for water are identified and described with emphasis on the mechanism of adsorption, modification, improvement of the water sorption capacity, possible regeneration, and stabilization. Among the three main groups of water sorbents, i.e. inorganic materials (zeolites, clays, silica), carbon based materials and organic polymers, the first one is described in details. The significance of their porosity, chemical and structural features relative to the water adsorptive properties of each inorganic type materials is reviewed. Important features for silicates, zeolites, aluminophosphates, mesoporous materials and clays are described, which define the interactions between the water and the …


Dielectric Relaxation Behaviour Of Glycine In Acqueous Solution Medium In The Microwave Frequency Region, Ajaya Kumar Kavala Apr 2008

Dielectric Relaxation Behaviour Of Glycine In Acqueous Solution Medium In The Microwave Frequency Region, Ajaya Kumar Kavala

Mr Ajaya Kumar Kavala

No abstract provided.


Alpo-18 Seed Layers And Films By Secondary Growth, Lubomira Tosheva, Eng-Poh Ng, Svetlana Mintova, Manfred Holzl, Till H. Metzger, Aidan M. Doyle Jan 2008

Alpo-18 Seed Layers And Films By Secondary Growth, Lubomira Tosheva, Eng-Poh Ng, Svetlana Mintova, Manfred Holzl, Till H. Metzger, Aidan M. Doyle

Eng-Poh Ng

AlPO-18 layers were prepared on Si wafers via spin-coating or the Langmuir−Blodgett (LB) method using nanosized crystals. Multilayers were deposited by spin-coating, whereas the seeds assembled by the LB technique were monolayers. The seeded layers were not stable upon secondary growth under microwave radiation, and no films were formed on the supports. Dense AlPO-18 films could be obtained by secondary growth after stabilization of the seed layers by adding prehydrolyzed tetraethylorthosilicate (TEOS) to the colloidal AlPO-18 suspension prior to support seeding. The stabilized seed layers and the grown AlPO-18 films were stable. The structure and the morphology of the films …


What More In Nanosized Molecular Sieves, Eng-Poh Ng, Gerardo Majano, Louwanda Lakiss, Svetlana Mintova Jan 2007

What More In Nanosized Molecular Sieves, Eng-Poh Ng, Gerardo Majano, Louwanda Lakiss, Svetlana Mintova

Eng-Poh Ng

No abstract provided.


Sulphated Almcm-41: Mesoporous Solid Brønsted Acid Catalyst For Dibenzoylation Of Biphenyl, Eng-Poh Ng, Hadi Nur, Mohd Nazlan Mohd Muhid, Halimaton Hamdan Jan 2006

Sulphated Almcm-41: Mesoporous Solid Brønsted Acid Catalyst For Dibenzoylation Of Biphenyl, Eng-Poh Ng, Hadi Nur, Mohd Nazlan Mohd Muhid, Halimaton Hamdan

Eng-Poh Ng

Sulphated mesoporous solid Brønsted acid catalyst (SO4-AlMCM-41) was prepared by impregnation of sulphuric acid on the surface of H-AlMCM-41. Characterization of SO4-AlMCM-41 by pyridine adsorption studies and 27Al MAS NMR showed that the presence of Brønsted acidity was correlated with octahedrally coordinated aluminium and solvent environment. Catalytic study demonstrated that the SO4-AlMCM-41 catalyst has a higher activity in the dibenzoylation of biphenyl with benzoyl chloride than sulphuric acid, H-AlMCM-41 and sulphated amorphous silica.