Publications by authors named "Jacques Eksteen"

The adsorption behaviour of micro-organisms during the initial attachment stage of biofilm formation affects subsequent stages. The available area for attachment and the chemophysical properties of a surface affect microbial attachment performance. This study focused on the initial attachment behaviour of on monazite by measuring the ratio of planktonic against sessile subpopulations (P:S ratio), and the potential role of extracellular DNA (eDNA).

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Microbial attachment and biofilm formation is a ubiquitous behaviour of microorganisms and is the most crucial prerequisite of contact bioleaching. Monazite and xenotime are two commercially exploitable minerals containing rare earth elements (REEs). Bioleaching using phosphate solubilizing microorganisms is a green biotechnological approach for the extraction of REEs.

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Waste printed circuit boards (WPCBs) constitute a hazardous material with up to 40 different metals, including numerous many heavy metals and environmentally harmful metals. Most hydrometallurgical processing approaches use high concentrations of toxic reagents and generate significant amounts of harmful effluents. This research investigates the use of cyanide-starved glycine solution containing no free cyanide in the leachate to extract precious metals from WPCBs, with most of copper and base metals pre-removed by upstream glycine-only leaching.

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In an era of environmental degradation, and water, and mineral scarcity, enhancing microbial function in sustainable mining has become a prerequisite for the future of the green economy. In recent years, the extensive use of rare earth elements (REEs) in green and smart technologies has led to an increase in the focus on recovery and separation of REEs from ore matrices. However, the recovery of REEs using traditional methods is complex and energy intensive, leading to the requirement to develop processes which are more economically feasible and environmentally friendly.

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There is an increasing trend in the occurrence of coal worker's pneumoconiosis even in developed countries such as the US and Australia who have believed such an issue have been well controlled in the past. Water spray is one of the most commonly applied methods for underground coal mines dust control, and research have shown the dust suppression efficiency can be greatly improved by adding surfactants. However, the literature appears to show inconsistent results that do not provide the coal mining industry with a clearly effective solution.

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The unique physiochemical properties exhibited by rare earth elements (REEs) and their increasing application in high-tech industries has created a demand for secure supply lines with established recovery procedures that create minimal environmental damage. Bioleaching experiments conducted on a non-sterile monazite concentrate with a known phosphate solubilising microorganism (PSM) resulted in greater mobilisation of REEs into solution in comparison to experiments conducted on sterile monazite. By combining the native consortia with an introduced PSM, a syntrophic effect between the populations effectively leached a greater amount of REEs than either a single PSM or the indigenous population alone.

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Many microbial species are capable of solubilising insoluble forms of phosphate and are used in agriculture to improve plant growth. In this study, we apply the use of known phosphate solubilising microbes (PSM) to the release of rare-earth elements (REE) from the rare-earth phosphate mineral, monazite. Two sources of monazite were used, a weathered monazite and mineral sand monazite, both from Western Australia.

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