https://nova.newcastle.edu.au/vital/access/ /manager/Index en-au 5 https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:24419 Wed 10 Nov 2021 15:05:12 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:2947 Sat 24 Mar 2018 08:29:08 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:2948 Sat 24 Mar 2018 08:29:08 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:28139 −1). The objective was to understand how bioaccessible As by different methods was related to different As pools based on sequential extraction and 0.43 M HNO₃ extraction. Arsenic bioaccessibility was 7.6–25, 2.3–49, 7.3–44, and 1.3–38% in gastric phase (GP), and 5.7–53, 0.46–33, 2.3–42, and 0.86–43% in intestinal phase (IP) for UBM, SBRC, IVG, and PBET, respectively, with HNO₃-extractable As being 0.90–60%. Based on sequential extraction, As was primarily associated with amorphous (AF3; 17–79%) and crystallized Fe/Al oxides (CF4; 6.4–73%) while non-specifically sorbed (NS1), specifically sorbed (SS2), and residual fractions (RS5) were 0–10%, 3.4–20% and 3.2–25%. Significant correlation was found between As bioaccessibility by PBET and NS1 + SS2 (R² = 0.55 − 0.69), and UBM-GP and NS1 + SS2 + AF3 (R² = 0.58), indicating PBET mostly targeted As in NS1 + SS2 whereas UBM in NS1 + SS2 + AF3. HNO₃-extractable As was correlated to bioaccessible As by four methods (R² = 0.42 – 0.72) with SBRC-GP having the best correlation. The fact that different methods targeted different As fractions in soils suggested the importance of validation by animal test. Our data suggested that HNO₃ may have potential to determine bioaccessible As in soils.]]> Sat 24 Mar 2018 07:36:39 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:29332 Sat 24 Mar 2018 07:34:22 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:48272 Mon 13 Mar 2023 18:44:54 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:45759 Fri 04 Nov 2022 11:02:02 AEDT ]]>