ARC Research Hub for Graphene Enabled Industry Transformation

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Browsing ARC Research Hub for Graphene Enabled Industry Transformation by Author "Andelkovic, I."

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    Addressing challenges in providing a reliable ecotoxicology data for graphene-oxide (GO) using an algae (Raphidocelis subcapitata), and the trophic transfer consequence of GO-algae aggregates
    (Elsevier, 2019) Markovic, M.; Andelkovic, I.; Shuster, J.; Janik, L.; Kumar, A.; Losic, D.; McLaughlin, M.J.
    The graphene oxide (GO) due to its exceptional structure, physicochemical and mechanical properties is a very attractive material for industry application. Even though, the unique properties of GO (e.g. structure, size, shape, etc.) make the risk assessment of this nanomaterial very challenging in comparison with conventional ecotoxicology studies required by regulators. Thus, there is a need for standardized characterization techniques and methodology to secure a high quality/reliable data on the ecotoxicology of GO, and to establish environmentally acceptable levels. Herein, authors address the crucial quality criteria when evaluating the ecotoxicology of GO using an algae (Raphidocelis subcapitata) and a shrimp (Paratya australiensis). This study provides a detail characterization and modification of the used GO, robust quantification and a suspension stability in different media for ecotoxicology studies. It was observed that under the same exposure conditions the behavior of GO and the estimated outcomes (IC50 values) in modified algae media differed in comparison to the referent media. Further to that, the adverse effects of GO on the algae cell structure and the potential uptake of GO by the algae cells were examined using the TEM with different staining techniques to avoid artefacts. Shrimps which were exposed to GO-algae aggregates via the food intake did not indicate stress or accumulation of GO. Our work presents an important insight to necessity of establishing a benchmark ecotoxicology assays for GO (e.g. characterization techniques, choice of media, etc.) and providing a reliable data to be used by regulators in risk assessment of two-dimensional (2D) nanomaterials.
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    Cogranulation of low rates of graphene and graphene oxide with macronutrient fertilizers remarkably improves their physical properties
    (American Chemical Society, 2018) Kabiri, S.; Baird, R.; Tran, D.; Andelkovic, I.; McLaughlin, M.; Losic, D.
    The beneficial effects of graphene (GN) and graphene oxide (GO) additives on the physical properties of monoammonium phosphate (MAP) fertilizer granules were investigated. Low doses (0.05 to 0.5% w/w) of GN and GO sheets were cogranulated with MAP and effects on the crushing strength, abrasion and impact resistance of prepared granules were evaluated. Cogranulation with 0.5% w/w GN sheets (MAP-GN) significantly enhanced the mechanical strength of MAP granules (∼18 times improvement) whereas inclusion of same amounts of GO sheets (MAP-GO) improved the strength to a lesser extent (∼8 times improvement). The cogranulation of GN also improved MAP granules resistance to abrasion (>70%) and impact resistance (>75%). Heating MAP-GO granules at 50 °C after granulation is shown to enhance their physical properties in comparison to MAP-GO granules dried under ambient temperatures. The advantages of GN and GO sheets compared with current additives in enhancing the physical properties of MAP granules are explained by their high specific area, superior nanofiller–matrix and adhesion/interlocking ability arising from their unique wrinkled structures and two-dimensional (2D) geometry. These results confirm the potential of GN/GO additives to enhance the physical properties of MAP granules that could be translated to other fertilizers and applied in the industry.
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    Engineered phosphate fertilisers with dual-release properties
    (American Chemical Society, 2020) Kabiri, S.; Andelkovic, I.; Coqui da Silva, R.; Degryse, J.; Baird, R.; Tavakkoli, E.; Losic, D.; McLaughlin, M.
    A new strategy to produce phosphate (P) fertilizers with both fast and slowly soluble P by the compaction method to produce composite products is presented. This unique composition is created by combining monoammonium phosphate (MAP) as a highly soluble P nutrient source, with a commercially available slow-release P such as struvite (Str) or P-loaded graphene oxide (GO). Graphene oxide-loaded P was synthesized by in situ oxidation of GO and ferrous ion (GO-Fe) mixtures with hydrogen peroxide and further loading of P onto the GO-Fe composite. The nutrient release in water was studied for dual-release MAP-Str and MAP-GO-Fe-P and compared to their corresponding slow- and fast-release sources. Column perfusion experiments showed a biphasic dissolution behavior with no significant difference between MAP-GO-Fe-P and MAP-Str. Visualization of P diffusion and chemical analysis of the soil after diffusion were used to assess the diffusion of P from different P fertilizers in various types of soil. Runoff and leaching simulations were performed to investigate the effects of the prepared fertilizer formulations on the environment. Overall, the diffusion of the dual-release fertilizers and the P loss in runoff and leaching experiments were less than for MAP. The better environmental performance of the dual-release fertilizers compared to MAP was related to the specific properties of the GO-based materials such as their two-dimensional structure and to the low solubility of the Str in the case of Str-based fertilizers.
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    Graphene oxide-Fe(III) composite containing phosphate - a novel slow release fertilizer for improved agriculture management
    (Elsevier, 2018) Andelkovic, I.; Kabiri, S.; Tavakkoli, E.; Kirby, J.; McLaughlin, M.; Losic, D.
    Novel materials offer opportunities to develop new types of fertilizers which could potentially increase efficiency of nutrient use in agriculture. Slow-release fertilizers can be more effective than traditional nutrient sources and simultaneously reduce negative impacts of nutrients to the environment. Using low-cost, abundant natural material, graphite rock, a functionalized graphene oxide (GO)/iron (GO-Fe) composite was synthetised and examined as a new carrier of phosphate ions in order to improve nutrient delivery to plants. The morphology of the composite was examined with scanning electron microscopy (SEM), and X-ray diffraction (XRD) was used to determine the presence of crystal phases. The composite was also characterised with thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FTIR). We found that the presence of ferric ions was responsible for attachment of phosphate ions onto the GO-Fe composite, providing a loading capacity of 48 mg P/g. The kinetics of P release were examined using a column perfusion test while P diffusion in three different types of soils was examined using a visualization technique and chemical analysis. Compared with commercial monoammonium phosphate (MAP) fertilizer, application of GO-Fe composite loaded with phosphate (GO-Fe-P) resulted in slower release of P, thus reducing the possibility for leaching or runoff of soluble P to surface and groundwaters.