D. M. S. N. Dissanayake | Sri Lanka Institute of Nanotechnology (original) (raw)

Papers by D. M. S. N. Dissanayake

Omniphobic surfaces have been widely used in many applications, especially due to their self-clea... more Omniphobic surfaces have been widely used in many applications, especially due to their self-cleaning property. Omniphobicity of a surface is directly interpreted by measuring the contact angle that it makes with a liquid of interest. In this study, polyester fabric was made omniphobic with a measured water contact angle (WCA) of 152° by reducing the surface free energy of the fabric surface via the polymerization of 3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl methacrylate(TDM) on a ZnO seed layer. The fabrics with and without the seed layer were characterized using various analytical techniques. The WCA of the fabric with the seed layer was 153° compared to 142° of the fabric without the seed layer. The treated fabric made a contact angle of 132° with SAE 40 motor oil indicating its oleophobicity while non-treated fabric made no contact angle. In addition to that, the treated fabric is omniphobic against milk tea, coffee, coconut oil, and ethanol. The morphological analysis using ...

Thin films of akaganeite [FeO(OH)] nanorices deposited muscovite mica (ANPM) surfaces are synthes... more Thin films of akaganeite [FeO(OH)] nanorices deposited muscovite mica (ANPM) surfaces are synthesized using the facile urea assisted controlled self-assembly technique. The synthesized materials are characterized using scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy, atomic force microscopy, X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy and thermogravimetric analysis (TGA). The prepared nanorices on mica surfaces show average particle length and width as 200 nm and 50 nm, respectively. Synthesized material acts as an efficient photocatalyst under UV and sunlight conditions as demonstrated by the degradation of standard methylene blue (MB) solution. The MB degradation efficiencies of the catalyst under exposure to 180 min sunlight and UV are 89% and 87.5%, respectively, which shows that the catalyst is highly active under sunlight than under UV light. Therefore, the synthesized material is a potential green photocatalyst in effi...

Royal Society Open Science, 2019

Thin films of akaganeite [FeO(OH)] nanorices deposited muscovite mica (ANPM) surfaces are synthes... more Thin films of akaganeite [FeO(OH)] nanorices deposited muscovite mica (ANPM) surfaces are synthesized using the facile urea assisted controlled self-assembly technique. The synthesized materials are characterized using scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy, atomic force microscopy, X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy and thermogravimetric analysis (TGA). The prepared nanorices on mica surfaces show average particle length and width of 200 and 50 nm, respectively. Synthesized material acts as an efficient photocatalyst under UV and sunlight conditions as demonstrated by the degradation of standard methylene blue (MB) solution. The MB degradation efficiencies of the catalyst under exposure to 180 min sunlight and UV are 89% and 87.5%, respectively, which shows that the catalyst is more highly active under sunlight than under UV light. Therefore, the synthesized material is a potential green photocatalyst in ef...

Journal of the Geological Society of Sri Lanka, 2020

In this work, disc-like hematite (Fe2O3) nanoparticles were prepared using a readily available in... more In this work, disc-like hematite (Fe2O3) nanoparticles were prepared using a readily available inexpensive earth material, ferruginous laterite, via a low-cost synthesis route. Prepared hematite nanoparticles were characterized using X-Ray diffraction (XRD), inductively coupled plasma mass spectroscopy (ICP-MS), particle size analyzer (PSA), Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), and nitrogen adsorption-desorption analyzer. The performance of hematite nanoparticles was evaluated as a heavy metal ion adsorbent. Batch adsorption experiments were conducted to study the adsorption behaviour of Ni2+ and Cd2+ ions as a function of the amount of adsorbent, contact time, and pH. Adsorption data fitted to the linearized Langmuir and Freundlich kinetic models were compared and discussed. The correlation coefficient (R2) was used to determine the best fit kinetic model. Our data fitted the Langmuir kinetic model well and the highest adsorption effi...

Materials Research Express, 2019

© 2019 IOP Publishing Ltd. Laterite is an iron-rich earth material containing naturally occurring... more © 2019 IOP Publishing Ltd. Laterite is an iron-rich earth material containing naturally occurring minerals such as hematite (Fe2O3), magnetite (Fe3O4), goethite (Fe3+O(OH)), gibbsite (Al(OH)3) and kaolinite (Al2Si2O5(OH)4). Even though these laterites are negligibly used as a cheap raw material in the brick manufacturing industry, they could be used in the synthesis of advanced materials including iron oxide nanoparticles and nanocomposites for a broad range of applications. Therefore, for the first time, this study focuses on the synthesis of iron oxide nanoparticles using laterites as a cheap raw material. In this method, first, iron and aluminium components of laterites were extracted into hydrochloric acid as their corresponding metallic ions. The extracted solution was then, mixed with sodium dodecyl sulphate (SDS) and the mixture was added dropwise to a basic solution maintaining the pH around 14 while stirring. The obtained ferric hydroxide nanoparticles were calcined to obta...

In this study, chitosan nanocomposite thin films were successfully fabricated by incorporating he... more In this study, chitosan nanocomposite thin films were successfully fabricated by incorporating hematite nanoparticles (HNPs) and akaganeite nanoparticles (ANPs) as reinforcing fillers using the solution casting method. HNPs and ANPs were synthesized via a urea-assisted synthesis route using naturally occurring ferruginous laterites. Scanning electron microscopic (SEM) images indicated the spherical to subhexagonal morphology of the HNPs and rice-like morphology of the ANPs. X-ray diffractograms indicate the crystalline structure of iron oxides as hematite and akaganeite. Tensile tests were carried out to evaluate the mechanical properties of the nanocomposite films where maximum tensile stress of the chitosan/HNP composites was improved as high as 35.7% while chitosan/ANP composites indicated 43.5%. Thermal decomposition curves obtained by thermogravimetric analysis (TGA) indicate that the thermal stability of the nanocomposites has improved remarkably compared to neat chitosan film...

Mica is a relatively abundant mineral found on earth’s crust and is used in various industries su... more Mica is a relatively abundant mineral found on earth’s crust and is used in various industries such as paint, construction, electronics, water sciences and so on, due to various properties including softness, lightness, chemical inertness, thermal and electrical stability. This study is an attempt to showcase the potential of value addition to muscovite mica as a photocatalytic agent when a nanocomposite with ZnO is formed. Herein, ZnO nano-layer was deposited on muscovite mica surface and the deposition mechanism was studied. Then this nanocomposite was studied for its photocatalytic degradation ability in the methylene blue dye degradation studies under UV light. The Scanning electron microscopy suggested that the deposited ZnO layer changes its morphology from an oval shape to flower-like morphology when the shape of the mica sheet differs from square to rectangular respectively and the material turns out to be highly reactive against methylene blue dye under UV irradiation havin...

RSC Advances

High purity hematite nanoparticles have been synthesized by a facile method using naturally occur... more High purity hematite nanoparticles have been synthesized by a facile method using naturally occurring laterites for industrial dye effluent treatment applications.

Journal of the Geological Society of Sri Lanka, 2020

Magnetite nanomaterials are immensely valuable in the biomedical, water science, electronic and b... more Magnetite nanomaterials are immensely valuable in the biomedical, water science, electronic and bioengineering fields because of their para-magnetic property and biocompatibility. Nevertheless, the cost of these materials is very high although it is regularly used in most applications in modern industries. To address the issue, the present study is focused to synthesize magnetite nano-spheres assembled nano-architectures. The low cost and locally available laterite was used as a source of iron. The extracted iron was purified and converted into magnetite by a sol-gel synthesis method. The synthesized iron nanoparticles were characterized using X-ray diffraction (XRD), Scanning Electron Microscopic (SEM) and Thermogravimetric (TG) techniques. The obtained results confirmed that 50 nm of spherical magnetite particles were formed. Also, the particles showed some picturesque self-assemblies when the pH of the precursor-solution of the sol-gel process and the rate of annealing are changed. TG analysis reveals that the annealing temperature is 500°C. X-ray diffraction pattern of the product is comparable with commercially available nano-magnetite as well as the same material produced using chemicals using the same method. These prepared nano-architectures have potential applications in drug delivery, electronic devices and medical imaging.

Hematite nanoparticles have a broad range of outstanding applications such as in wastewater treat... more Hematite nanoparticles have a broad range of outstanding applications such as in wastewater treatment, electrolytic studies, and photoelectrochemical and superparamagnetic applications. Therefore, the development of facile and novel methods to synthesize hematite nanoparticles using low-cost raw materials is an important and timely requirement. In this study, we have developed a facile economical route to synthesize hematite nanoparticles, directly from the naturally occurring material laterite. Laterite is a rock that is rich in Fe and Al with extensive distribution in large mineable quantities in many countries around the world, though not yet utilized for major industrial applications. In this method, ferric ions in the laterite were leached out using acid and the solution obtained was hydrolyzed with slow-release hydroxyl ions which were acquired by aqueous decomposition of urea. The resulted precursor was calcined to obtain hematite nanoparticles. Characterization data shows that the final product is comprised of spherical hematite nanoparticles with a narrow particle size vs. frequency distribution with an average particle diameter of 35 nm. The synthesized product has a purity of over 98%. Furthermore, the synthesized nanoparticles show an excellent adsorption percentage as high as 70%, even when the initial dye concentration in water is 5000 ppm and the amount of material is minimal, towards acid dyes which are excessively used in textile based industries. Such acid dyes are a threat to the environment when they are released into water bodies by industries in massive quantities. Therefore synthesized hematite nanoparticles are ideal to treat dye wastewater in industrial effluents because such nanoparticles are low cost and economical, and the synthesis procedure is rather facile and effective.

Ferruginous laterites are widely distributed in Sri Lanka at locations such as Colombo, Kaluthara... more Ferruginous laterites are widely distributed in Sri Lanka at locations such as Colombo,
Kaluthara and Rathnapura districts and most parts of the south western coastline with
large mineable quantities. However currently, industrial application of Sri Lankan
ferruginous laterite is limited only to small-scale production of bricks. Nevertheless such
laterite deposits could be used to manufacture value-added products including iron
oxides and their nanomaterials, which bear a significant global demand. Such materials
have a broad-range of applications such as catalysis, information storage, adsorbents,
drug delivery, magnetic resonance imaging (MRI), nano-tagging and waste water
treatment. Therefore, this study focuses on synthesis of high purity iron oxides using Sri
Lankan ferruginous laterites as a value added product. For the present study, laterite
samples were collected from Homagama area. Chemical analyses of laterite show that
they are characterized by mainly of iron oxides with minor aluminium and silica oxides.
Herein, a devised method to synthesize high purity iron oxides was developed. First, the
laterite powder (5 g) was reacted with 5 M HCl at 100 0C under reflux conditions. Iron
and aluminium components of laterites were digested in HCl and quartz was
precipitated. The solution was separated out by filtering and reacted with Na2CO3
solution to precipitate iron hydroxides and hydrated aluminium oxide. The precipitate
was suspended in water and reacted with sucrose to extract the iron hydroxides into the
solution as iron sucrose complex. Then the solution was filtered out and its pH was
reduced to 7 by adding HCl, in order to obtain high purity iron hydroxide precipitate
which was later calcined at 5000C to produce high purity iron oxide. Synthesized
compound was characterized using X-ray diffraction (XRD), Fourier Transformed
Infrared (FT-IR) spectroscopy, Thermo Gravimetric Analysis (TGA), and X-ray
Fluorescence (XRF) techniques. This novel method can certainly be used to synthesize
high purity iron oxides as a value added product from Sri Lankan ferruginous laterit

Royal Society Open Science, 2019

Thin films of akaganeite [FeO(OH)] nanorices deposited muscovite mica (ANPM) surfaces are synthes... more Thin films of akaganeite [FeO(OH)] nanorices deposited muscovite mica (ANPM) surfaces are synthesized using the facile urea assisted controlled self-assembly technique. The synthesized materials are characterized using scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy, atomic force microscopy, X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy and thermogravimetric analysis (TGA). The prepared nanorices on mica surfaces show average particle length and width of 200 and 50 nm, respectively. Synthesized material acts as an efficient photocatalyst under UV and sunlight conditions as demonstrated by the degradation of standard methylene blue (MB) solution. The MB degradation efficiencies of the catalyst under exposure to 180 min sunlight and UV are 89% and 87.5%, respectively, which shows that the catalyst is more highly active under sunlight than under UV light. Therefore, the synthesized material is a potential green photocatalyst in ef...

Journal of the Geological Society of Sri Lanka, 2020

Materials Research Express, 2019

RSC Advances

Journal of the Geological Society of Sri Lanka, 2020