https://ogma.newcastle.edu.au/vital/access/ /manager/Index en-au 5 https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:46449 Wed 23 Nov 2022 14:10:37 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:37280 4) to organic oxygenates utilizing heterogeneous and homogeneous processes conducted in the gaseous or liquid phase is reviewed. The most active catalytic systems are examined in terms of rates, longevity, and reaction mechanisms. Despite significant effort, the successful heterogeneous mimicking of selective CH₄ oxidation performed in an enzymatic system (methane monooxygenase) is still elusive. Under mild reaction conditions, the reaction is too slow, and under harsh conditions, total oxidation prevails. Thus, of particular interest herein is the assessment of oxidation at intermediate temperatures to 1) reduce total oxidation and 2) obtain sufficient concentration of activated oxygen and CH₄ species. Important operational parameters such as reaction conditions, catalyst preparation methods, and cofeeding of chemicals, which significantly affect the yield of desired products, are discussed. One particular system that is successful is the catalytic conversion of CH₄ to methanol under mild conditions using nitrous oxide (N₂O) with Fe-based catalysts or oxygen (O₂) with Cu-based catalysts. Special attention is paid to the controversy related to the identification of active sites, where the oxygen species suitable for CH₄ oxidation are purportedly formed.]]> Wed 16 Sep 2020 18:36:19 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:601 Wed 11 Apr 2018 13:01:22 AEST ]]> https://ogma.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://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:34057 in situ by embedding magnetite into the palygorskite structure through co-precipitation method. The physico-chemical characteristics of Pal-IO and their pristine components were examined through various spectroscopic and micro-analytical techniques. Batch adsorption experiments were conducted to evaluate the performance of Pal-IO in removing Pb(II) from aqueous solution. The surface morphology, magnetic recyclability and adsorption efficiency of regenerated Pal-IO using desorbing agents HCl (Pal-IO-HCl) and ethylenediaminetetraacetic acid disodium salt (EDTA-Na₂) (Pal-IO-EDTA) were compared. The nanocomposite showed a superparamagnetic property (magnetic susceptibility: 20.2 emu g^-1) with higher specific surface area (99.8 m² g^-1) than the pristine palygorskite (49.4 m² g^-1) and iron oxide (72.6 m² g^-1). Pal-IO showed a maximum Pb(II) adsorption capacity of 26.6 mg g^-1 (experimental condition: 5 g L^-1 adsorbent loading, 150 agitations min^-1, initial Pb(II) concentration from 20 to 500 mg L^-1, at 25 °C) with easy separation of the spent adsorbent. The adsorption data best fitted to the Langmuir isotherm model (R² = 0.9995) and pseudo-second order kinetic model (R² = 0.9945). Pb(II) desorption using EDTA as the complexing agent produced no disaggregation of Pal-IO crystal bundles, and was able to preserve the composite's magnetic recyclability. Pal-IO-EDTA exhibited almost 64% removal capacity after three cycles of regeneration and preserved the nanocomposite's structural integrity and magnetic properties (15.6 emu g^-1). The nanocomposite holds advantages as a sustainable material (easily separable and recyclable) for potential application in purifying heavy metal contaminated wastewaters.]]> Tue 05 Feb 2019 12:51:19 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:43843 Tue 04 Oct 2022 11:46:23 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:45345 −1 for 24 h by Zr–FeBC and Fe-BC at pH 5 and 4, respectively. Desorption studies were performed to investigate the reusability, cost-effectiveness and stability of the adsorbents Zr–FeBC and Fe-BC. The adsorption–desorption study suggests that both examined biochars have considerable potentiality as adsorbent candidates in removing as well as recovery of P from wastewaters. Results also reveal that the regenerated Zr–FeBC and Fe–BC could be utilized repetitively in seven adsorption–desorption cycles using NaOH as a desorbing agent, which greatly reduces the P-removal cost from wastewaters. Thus, P enriched biochar could potentially be used as fertilizer in the agriculture sector.]]> Thu 27 Oct 2022 15:20:47 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:38611 Thu 18 Nov 2021 14:12:30 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:8152 Sat 24 Mar 2018 08:36:07 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:27741 Sat 24 Mar 2018 07:27:46 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:30966 Sat 24 Mar 2018 07:27:32 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:3142 Sat 24 Mar 2018 07:18:17 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:40441 S-Zn > S-Pb and C-Zn > T-Cd > C-Pb. PET particles exposed to Zn, Cd, and Pb solution adsorbed from 7.2 to 8.5%, 5.3 to 9.8%, and 29.8 to 68.5% of the initial heavy metals concentration, respectively. 11.3 to 15.2%, 12.5 to 23.35%, and 5.5 to 33.6% of the initially adsorbed Zn, Cd, and Pb were desorbed in the wheat rhizosphere zone in the three defined scenarios, respectively. The results show that PET particles can act as a vector in transferring heavy metals to the rhizosphere zone.]]> Fri 22 Jul 2022 14:31:16 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:42230 Fri 19 Aug 2022 11:35:34 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:41795 Fri 12 Aug 2022 12:24:33 AEST ]]>