Mawson Lakes, Australia
Mawson Lakes, Australia
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Okour Y.,University of Technology, Sydney | Shon H.K.,University of Technology, Sydney | El Saliby I.J.,University of Technology, Sydney | Naidu R.,CRC CARE | And 2 more authors.
Bioresource Technology | Year: 2010

In this study, titanium (Ti), ferric (Fe) and aluminum (Al) salt flocculants were compared for their efficiency in treating wastewater collected from Sydney Olympic Park wastewater treatment plant by following the jar test procedure. Produced sludge from Ti-salt flocculation was dried and titanium dioxide (TiO2) nanoparticles were generated after the incineration of sludge produced from the Ti-salt flocculation of wastewater. Later on, titanate nanotubes were synthesized after TiO2 nanoparticles were hydrothermally treated with 10 N NaOH solution at 130oC for 24 h. Titanate nanotubes were either acid or deionised water-washed, while thiourea-doping was employed to produce visible light-responsive nanotubes. Wastewater flocculation using Ti-salt was found to be as efficient as Fe and Al flocculation in terms of turbidity and DOC removal. XRD results showed that the anatase structure was predominant for TiO2 nanoparticles, while thiourea-doped titanate nanotubes only indicated anatase structure with an increased crystallinity after being crystallized at 600oC. The photocatalytic activity of all photocatalysts was evaluated using the photooxidation of acetaldehyde. Thiourea-doped nanotubes showed a greater photocatalytic activity than as-prepared TiO2 nanoparticles, deionised water-washed, acid-washed titanate nanotubes and P25 under UV and visible light irradiation. © 2009.

Aryal R.,University of Technology, Sydney | Vigneswaran S.,University of Technology, Sydney | Kandasamy J.,University of Technology, Sydney | Naidu R.,CRC CARE
Korean Journal of Chemical Engineering | Year: 2010

Stormwater runoff from urban and suburban areas generates numerous pollutants. The areas include residential areas, parks, commercial areas, industrial areas and road/highways. Land use and human activities largely determine the nature and level of pollutants. Among the various types of pollutants that can contribute to adverse water quality impact in receiving water bodies, of concern are suspended solids, heavy metals, polycyclic aromatic hydrocarbons and nutrients. This paper provides a critical review of the characteristics and sources of urban stormwater pollutants and the manner in which the pollution occurs. Treatment systems for urban stormwater runoff and for urban stormwater harvesting are discussed. © 2010 Korean Institute of Chemical Engineers, Seoul, Korea.

Chekli L.,University of Technology, Sydney | Zhao Y.X.,University of Technology, Sydney | Zhao Y.X.,Shandong University | Tijing L.D.,University of Technology, Sydney | And 6 more authors.
Journal of Hazardous Materials | Year: 2014

Adsorption of natural organic matter, aggregation and disaggregation have been identified as three of the main processes affecting the fate and behaviour of engineered nanoparticles (ENPs) in aquatic environments. However, although several methods have been developed to study the aggregation behaviour of ENPs in natural waters, there are only a few studies focusing on the fate of such aggregates and their potential disaggregation behaviour. In this study, we proposed and demonstrated a simple method for characterising the aggregation behaviour and aggregate structure of ENPs in different natural waters. Both the aggregate size of ENPs and their adsorption capacity for dissolved organic matter (DOM) were strongly related (R2>0.97, p<.05) to the combined effect of initial concentration of dissolved organic matter (DOM) and the ionic strength of the natural waters. The structure of the formed aggregates was strongly correlated (R2>0.95, p<.05) to the amount of DOM adsorbed by the ENPs during the aggregation process. Under high ionic strength conditions, aggregation is mainly governed by diffusion and the aggregates formed under these conditions showed the lowest stability and fractal dimension, forming linear, chain-like aggregates. In contrast, under low ionic strength conditions, the aggregate structure was more compact, most likely due to strong chemical binding with DOM and bridging mechanisms involving divalent cations formed during reaction-limited aggregation. © 2014 Elsevier B.V.

Chekli L.,University of Technology, Sydney | Phuntsho S.,University of Technology, Sydney | Roy M.,Australian National Measurement Institute | Lombi E.,University of South Australia | And 3 more authors.
Water Research | Year: 2013

Iron nanoparticles are becoming increasingly popular for the treatment of contaminated soil and groundwater; however, their mobility and reactivity in subsurface environments are significantly affected by their tendency to aggregate. Assessing their stability under environmental conditions is crucial for determining their environmental fate. A multi-method approach (including different size-measurement techniques and the DLVO theory) was used to thoroughly characterise the behaviour of iron oxide nanoparticles (Fe2O3NPs) under environmentally relevant conditions. Although recent studies have demonstrated the importance of using a multi-method approach when characterising nanoparticles, the majority of current studies continue to use a single-method approach.Under some soil conditions (i.e. pH 7, 10mM NaCl and 2mM CaCl2) and increasing particle concentration, Fe2O3NPs underwent extensive aggregation to form large aggregates (>1μm). Coating the nanoparticles with dissolved organic matter (DOM) was investigated as an alternative "green" solution to overcoming the aggregation issue instead of using the more commonly proposed polyelectrolytes. At high concentrations, DOM effectively covered the surface of the Fe2O3NPs, thereby conferring negative surface charge on the particles across a wide range of pH values. This provided electrostatic stabilisation and considerably reduced the particle aggregation effect. DOM-coated Fe2O3NPs also proved to be more stable under high ionic strength conditions. The presence of CaCl2, however, even at low concentrations, induced the aggregation of DOM-coated Fe2O3NPs, mainly via charge neutralisation and bridging. This has significant implications in regards to the reactivity and fate of these materials in the environment. © 2013 Elsevier Ltd.

Ma C.,Shaoguan University | Naidu R.,CRC CARE | Naidu R.,University of South Australia | Liu F.,Shaoguan University | And 3 more authors.
Biodegradation | Year: 2012

Cultivation of the biofuel plant, hybrid giant Napier grass (HGN), in saline soil was investigated in a greenhouse study. The results show that HGN is a salt tolerant plant which can flourish in saline soil and product a large amount of biomass. The extensively developed fibrous root system of HGN plays a significant role in the uptake of sodium from saline soil so that both soil salinity and pH are reduced. Fibrous roots of HGN are well distributed in the soil below the surface, where the metabolism of the root system produces a gradient at the depth between 10 and 20 cm in soil salinity, pH and organic content. The degradation of the HGN by the biota within the soil results in an increase in nutrients and improved soil quality. The experimental results suggest that HGN adapts to saline soil, which is promising for phytoremediation of such soils. Additional advantages of HGN include the large biomass produced which can be used for renewable energy generation. © 2012 Springer Science+Business Media B.V.

Donner E.,University of South Australia | De Jonge M.D.,Australian Synchrotron | Kopittke P.M.,CRC CARE | Kopittke P.M.,University of Queensland | Lombi E.,University of South Australia
Methods in Molecular Biology | Year: 2013

Synchrotron-based X-ray fluorescence (XRF) is allowing substantial advances in several disciplines of plant science by allowing the in situ examination of elements within plant tissues. Continual improvements in detector speed, sensitivity, and resolution are increasing the diversity of questions that can be addressed using this technique, including the in situ analysis of elements (such as nutrients or toxicants) within fresh and hydrated tissues. Here, we describe the general principles for designing and conducting experiments for the examination of elemental distributions in plant material using micro-XRF. © 2013 Springer Science+Business Media, LLC.

Lombi E.,University of South Australia | de Jonge M.D.,Australian Synchrotron | Donner E.,University of South Australia | Kopittke P.M.,CRC CARE | And 5 more authors.
PLoS ONE | Year: 2011

Metals and metalloids play a key role in plant and other biological systems as some of them are essential to living organisms and all can be toxic at high concentrations. It is therefore important to understand how they are accumulated, complexed and transported within plants. In situ imaging of metal distribution at physiological relevant concentrations in highly hydrated biological systems is technically challenging. In the case of roots, this is mainly due to the possibility of artifacts arising during sample preparation such as cross sectioning. Synchrotron x-ray fluorescence microtomography has been used to obtain virtual cross sections of elemental distributions. However, traditionally this technique requires long data acquisition times. This has prohibited its application to highly hydrated biological samples which suffer both radiation damage and dehydration during extended analysis. However, recent advances in fast detectors coupled with powerful data acquisition approaches and suitable sample preparation methods can circumvent this problem. We demonstrate the heightened potential of this technique by imaging the distribution of nickel and zinc in hydrated plant roots. Although 3D tomography was still impeded by radiation damage, we successfully collected 2D tomograms of hydrated plant roots exposed to environmentally relevant metal concentrations for short periods of time. To our knowledge, this is the first published example of the possibilities offered by a new generation of fast fluorescence detectors to investigate metal and metalloid distribution in radiation-sensitive, biological samples. © 2011 Lombi et al.

Ma C.J.,Shaoguan University | Ming H.,CRC CARE | Li H.S.,South China Agricultural University
Advanced Materials Research | Year: 2013

Currently, the comprehensive utilization of red mud has been a worldwide challenge. Due to high alkaline level and a serious lack of nutrients, a great amount of red mud has been stocked in the open rather than covered by plantations, which showed harms to the atmosphere, water and soil environment. In order to explore a more effective phytoremediation approach of red mud and screen plants with strong tolerance, the research group applied Pennisetum hybridum as the experiment material for a long term, which is a new energy plant in the field of ecological environmental management and restoring. Through the addition of different types of addictives, his experiment conducted the plantation Pennisetum hybridum based on red mud improvement matrix. Besides, a systematic research of the improvement effects of different ameliorants on red mud was conducted. Concurrently, the growth of Pennisetum hybridum in different groups of the experiment was investigated. Their mutual effect on the improvement effect of red mud was analyzed systematically. Results demonstrated that effective raw materials of red mud improvement include phosphogypsum, wastes of polluted and edible mushrooms. These can significantly reduce the pH and conductivity of red mud. After the improvement, Pennisetum hybridum can grow vigorously in the mixture matrix of red mud, and significantly improve the red mud matrix. Concurrently, considerable biomasses were obtained. The experiment results demonstrated that the addition of necessary nutriments for the plant growth was very important for red mud. The research has laid a solid foundation for the identification of the great potentials of Pennisetum hybridum in red mud phytoremediation, the further exploration of its role of restoring of red mud and the extensive application and promotion in the future. © (2013) Trans Tech Publications, Switzerland.

Katz A.,University of Sydney | McDonagh A.,CRC CARE | McDonagh A.,University of Sydney | Tijing L.,University of Sydney | Shon H.K.,University of Sydney
Critical Reviews in Environmental Science and Technology | Year: 2015

Titanium dioxide is an effective photocatalyst for the breakdown of many environmental contaminants. The complex mixtures that can occur in water matrices can significantly affect the breakdown of the contaminants in water by titanium dioxide (TiO2). The authors discuss a wide variety of foulants and inhibitors of photocatalytic TiO2 systems and review different methods that can be effective for their fouling prevention. Approaches to regenerate a fouled or contaminated TiO2 catalysts are explored and the effect of substrates on immobilized titanium dioxide is also reviewed. Copyright © 2015 Taylor & Francis Group, LLC.

Zhou Y.-F.,University of Queensland | Haynes R.J.,University of Queensland | Naidu R.,CRC CARE
Environmental Science and Pollution Research | Year: 2012

Purpose: This study aims to examine whether addition of immobilising agents to a sandy, alkaline (pH = 8. 1) soil, which had been contaminated with Pb and Zn by airborne particles from a Pb/Zn smelter, would substantially reduce metal bioavailability. Methods: The effectiveness of five waste materials (blast furnace (BF) slag, alum water treatment (WT) sludge, red mud, sugar mill mud and green waste compost) as metal immobilising agents was evaluated by incubating them with a contaminated soil for a period of 12 months at rates of 5% and 10% (w/w), after which, Rhodes grass was grown in the soils in a greenhouse study. Results: Additions of WT sludge, BF slag and red mud reduced CaCl2, CH3COOH, HCl and EDTA-extractable Zn but compost and mill mud had no appreciable immobilising effects. Additions of all amendments reduced levels of CaCl2, CH3COOH and HCl-extractable Pb although concentrations of EDTA-extractable Pb remained unchanged. A sequential extraction procedure showed that additions of mill mud and compost increased the percentage of total Pb and Zn present in the oxidisable fraction whilst additions of the other materials increased the percentage present in the residual fraction. Rhodes grass yields were promoted greatly by additions of red mud, compost and particularly mill mud, and yields were negatively correlated with tissue Pb concentrations and extractable Pb. Conclusions: Red mud was the most effective material for lowering extractable Pb and Zn levels simultaneously while mill mud and compost were notably effective for Pb. A field evaluation in the study area is justified. © 2011 Springer-Verlag.

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