https://nova.newcastle.edu.au/vital/access/ /manager/Index ${session.getAttribute("locale")} 5 https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:43514 Wed 21 Sep 2022 11:18:21 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:40272 Wed 13 Mar 2024 19:12:21 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:40637 0), enthalpically and entropically influenced. Increasing the incubation period and heat treatment resulted in a decrease of Be desorption and migration. The soil clay content and pH were the primary factors influencing Be desorption, and the results suggested that Be was desorbed from metal oxyhydroxides and surfaces of silicates (e.g., reactive surfaces of clay minerals), organic matters, and soil pores. Because of high Kd values, the mobility of Be was limited, and no exceedances of ecological or human health risk index or guidelines were determined for the current contamination levels at the site. However, Be released from the waste trenches has the ongoing potential to increase Be concentration in the soil.]]> Wed 07 Feb 2024 15:22:49 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:52210 2 (amorphous) from ICP standard solution, but a mixture of Be(OH)₂ (alpha), Be(OH)₂ (beta) and ternary Na/S-Be (ΙΙ)-OH(s) solid phase were formed from BeSO₄ solutions. The precipitation of Be started at relatively lower pH at higher concentrations than at the lower Be concentration as indicated by both laboratory data and simulation. Across the pH range, the Be sorption curve was divided into three phases, these being pH 3-6, pH 6-10, and pH > 10, within which sorption of Be with soil was 9-97%, 90-97%, and 66-90%, respectively. Beryllium solubility was limited at pH > 7, but a sorption study with soil showed chemisorption under both acidic and alkaline pH (pH 5.5 and 8) conditions, which was confirmed by FTIR and XPS analysis. At pH 5.5 (specifically relevant to the study site), sorption of Be was 72-95%, in which 77% and 46% Be was respectively sorbed by separated fulvic and humic acid fractions. The irreversible chemisorption mechanism was controlled by SOM at higher pH, and by metal oxyhydroxides at lower pH. Both organic and inorganic components synergistically influence the specific chemisorption of Be at the intermediate pH 5.5 of field soil.]]> Wed 07 Feb 2024 14:46:21 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:52380 12.5 g L−1 (soil/solution), considering higher sorption and limited desorption. Variable surface charges developed by different added ions (competing ions, counter ions, and co-existence of all ions) were not always correlated with Be sorption. However, effects of added ions in Be sorption (increased by counter ions and decreased by competing ions) primarily occurred at low pH, with no noticeable changes at pH > 6 due to the hydration and precipitation behaviour of Be at higher pH. Both laboratory data and modelling indicated the substantial effect of counter ions on increased sorption of Be. Relatively higher amounts of sorption under the co-existence of all added ions were suggested from synergistic actions. Sorption was favourable (KL > 0, and 0 < RL < 1) across all concentrations and temperatures at pH 5.5, and high retention (84–97%) occurred after four desorption cycles indicated specific sorption. The sorption process was exothermic (ΔH > −43 kJ mole−1), while desorption was endothermic (ΔH > +78.4 kJ mole−1). All sorption–desorption reactions were spontaneous (ΔG = −Ve), and executed without any structural deformation (ΔS = nearly zero) of soil particles. However, the effect of temperature on desorption was influenced by the concentrations of Be. Higher retention and different sorption–desorption parameters (Kd-desorption > Kd-sorption; Kf-desorption > Kf-sorption; ndesorption/nsorption < 1) indicate limited mobility of Be and the presence of desorption hysteresis in the studied soil under the experimental conditions.]]> Wed 07 Feb 2024 14:36:35 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:47041 Wed 07 Feb 2024 14:34:42 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:49060 Wed 03 May 2023 15:53:57 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:47667 3N₄/TiO₂ nanocomposite was prepared as a photocatalyst (PC) active under visible light (λ≥420 nm) by preparation of graphitic carbon nitride (g-C₃N₄) from melamine followed by an efective easy impregnation method. Several g-C₃N₄/ TiO₂ composites containing 1 to 12 wt% g-C₃N₄ were synthesized and characterized using X-ray difraction (XRD) analysis, scanning electron microscopy (SEM), thermogravimetric analysis (TGA), diferential thermal analysis (DTA), photoluminescence (PL) spectroscopy, difusion refectance spectroscopy (DRS), and Brunauer–Emmett–Teller (BET) measurements. A photocatalytic mechanism is proposed based on the relative positions of the energy bands of the two constituents. Compared with its individual components, g-C₃N₄/TiO₂ demonstrated unusually high photocatalytic activity for phenol decomposition in aqueous phase under visible-light irradiation. The heterojunction was optimized in the 5 wt% g-C₃N₄/TiO₂ nanocomposite due to the well-matched bandgap structure (optimum loading) and excellent electron–hole pair separation in the conduction and valence band of TiO₂ and g-C₃N₄, respectively. After 2 h of visible-light irradiation, 68 % degradation was observed when using this optimum composition. The performance was slightly decreased (to 66 %) after recycling of the catalyst four times (used a total of five times), but remained reliable for industrial applications considering other factors. In this system, TiO₂ (Degussa P25) seems to play the principal PC role, while g-C₃N₄ acts as a sensitizer for absorption of visible light. Due to the enhanced visible-light absorption ability enabled by g-C₃N₄ in the composite, stable electron–hole (e⁻–h⁺) pairs produced at the interface of the heterojunction lead to generation of highly reactive free radicals (·O₂, ·OH, etc.) which together initiate degradation of phenol but individually sufer from some limitation that must be overcome. The thermal stability and recycling efciency of this PC will enable its use in industrial applications as a cost-efective sustainable cleanup candidate.]]> Tue 24 Jan 2023 15:47:58 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:38254 Mon 29 Jan 2024 18:38:46 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:51538 Fri 08 Sep 2023 14:16:26 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:52954 Fri 03 Nov 2023 11:04:28 AEDT ]]>