title: Investigation of the potential of repurposing medium-density fiberboard waste as an adsorbent for heavy metal ion removal

authors: Ranaweera, Kavitha H

subjects: MDF waste

abstract: Medium-density fiberboard (MDF) waste generation has increased steadily over the past decades, and therefore, the investigation of novel methods to recycle this waste is very important. The potential of repurposing MDF waste as an adsorbent for the treatment of Cd(II), Cu(II), Pb(II), and Zn(II) ions in water was investigated using MDF offcuts. The highest adsorption potential in single-metal ion solution systems was observed for Pb(II) ions. The experimental data of Pb(II) ions fit well with the Freundlich isotherm and pseudo-second-order kinetic models. Complexation and electrostatic interactions were identified as the adsorption mechanisms. The adsorption behavior of multi-metal ion adsorption systems was investigated by introducing Cd(II) ions as a competitive metal ion. The presence of the Cd(II) ions reduced the adsorption potential of Pb(II) ions, yet the preference for the Pb(II) ions remained. Regeneration studies were performed by using 0.1 M HCl as a regeneration agent for both systems. Even though a significant amount of adsorbed metal ions were recovered, the adsorption potential of the MDF was reduced in the subsequent adsorption cycles. Based on these results, MDF fines have the potential to be used as an economical adsorbent for remediation of wastewater containing heavy metal ions.

text: Investigation of the potential of repurposing medium-density fiberboard waste as an adsorbent for heavy metal ion removal Medium-density fiberboard (MDF) waste generation has increased steadily over the past decades, and therefore, the investigation of novel methods to recycle this waste is very important. The potential of repurposing MDF waste as an adsorbent for the treatment of Cd(II), Cu(II), Pb(II), and Zn(II) ions in water was investigated using MDF offcuts. The highest adsorption potential in single-metal ion solution systems was observed for Pb(II) ions. The experimental data of Pb(II) ions fit well with the Freundlich isotherm and pseudo-second-order kinetic models. Complexation and electrostatic interactions were identified as the adsorption mechanisms. The adsorption behavior of multi-metal ion adsorption systems was investigated by introducing Cd(II) ions as a competitive metal ion. The presence of the Cd(II) ions reduced the adsorption potential of Pb(II) ions, yet the preference for the Pb(II) ions remained. Regeneration studies were performed by using 0.1 M HCl as a regeneration agent for both systems. Even though a significant amount of adsorbed metal ions were recovered, the adsorption potential of the MDF was reduced in the subsequent adsorption cycles. Based on these results, MDF fines have the potential to be used as an economical adsorbent for remediation of wastewater containing heavy metal ions.

year: 2024

title: Cycloaurated gold(III) complexes with monoanionic thiourea ligands

authors: Smith, Tiffany Sharee

subjects: gold complexes

abstract: Using a simple one-pot procedure, reaction of cycloaurated gold(III) dihalide complexes [LAuCl₂] (L = 2-benzylpyridyl, 2-anilinopyridyl) with trisubstituted thioureas PhNHC(S)NR₂ (R = Me, Cy) and Me3N in methanol, followed by addition of excess NaBPh₄ gave the salts [Lau{SC(-NR₂)NPh}]⁺BPH₄⁻ containing N,S-chelated thiourea monoanion ligands. The compounds were obtained in good yields, and were characterised by ESI MS, elemental microanalysis and in two cases by X-ray structure determinations. The series of complexes was extended by additional microscale reactions of LAuCl₂ complexes (L = 2-benzylpyridyl, 2-anilinopyridyl, 2-benzoylpyridyl or picolinamide) with a wide range of trisubstituted thioureas, with products identified by ESI MS.

text: Cycloaurated gold(III) complexes with monoanionic thiourea ligands Using a simple one-pot procedure, reaction of cycloaurated gold(III) dihalide complexes [LAuCl₂] (L = 2-benzylpyridyl, 2-anilinopyridyl) with trisubstituted thioureas PhNHC(S)NR₂ (R = Me, Cy) and Me3N in methanol, followed by addition of excess NaBPh₄ gave the salts [Lau{SC(-NR₂)NPh}]⁺BPH₄⁻ containing N,S-chelated thiourea monoanion ligands. The compounds were obtained in good yields, and were characterised by ESI MS, elemental microanalysis and in two cases by X-ray structure determinations. The series of complexes was extended by additional microscale reactions of LAuCl₂ complexes (L = 2-benzylpyridyl, 2-anilinopyridyl, 2-benzoylpyridyl or picolinamide) with a wide range of trisubstituted thioureas, with products identified by ESI MS.

year: 2013-11

title: Raising Māori Student Achievement - Journeys of Success

authors: Kaumoana, Cadence

abstract: Educational success for Māori students is influenced by confidence in one’s identity, positive role models and support; and positive attitudes to learning and success.
This project asked Māori tertiary graduates about their educational experiences. Half of the participants in this study had successfully completed secondary school and the other half did not complete secondary school education. This selection of participants was selected to highlight that although some students don’t complete secondary school it is still possible to successfully pursue and complete tertiary level qualifications. The feedback given from the participants highlighted the positive factors that influenced their successful completion. From these factors recommendations have been developed to support Māori student success. The objective of this study is to encourage the development of increased self-confidence for Māori rangatahi and to promote the continuation of lifelong learning.
When Māori students are supported both at school and in the home they are more likely to achieve educational success, particularly at secondary school level. Similarly, at tertiary level study; students who graduate with a completed degree qualification are likely to have had positive support and successful role models, they are likely to be secure within their own identity and wh!nau network. Māori students that successfully complete tertiary study are more likely to have positive attitudes to learning and to achieving; knowing how to access support and feeling confident in their efforts.
The key to this study is the link between successful completion of secondary school and the follow-on to successful tertiary study. When Māori students are supported appropriately in the development of their identity their confidence soon follows. This support would ideally come from wh!nau in the home and the school. When Māori students are confident in their learning journeys through high levels of confidence in identity they are more likely to persevere under pressure and despite setbacks.
Influencing factors to developing self-confidence for Māori students include awareness of Te Reo Māori and Tikanga Māori, responsibility at home, responsibility at school and the positive influence of role models. The study then concludes by providing recommendations for learners, educators and wh!nau to support the educational achievement of their tamariki.

text: Raising Māori Student Achievement - Journeys of Success Educational success for Māori students is influenced by confidence in one’s identity, positive role models and support; and positive attitudes to learning and success.
This project asked Māori tertiary graduates about their educational experiences. Half of the participants in this study had successfully completed secondary school and the other half did not complete secondary school education. This selection of participants was selected to highlight that although some students don’t complete secondary school it is still possible to successfully pursue and complete tertiary level qualifications. The feedback given from the participants highlighted the positive factors that influenced their successful completion. From these factors recommendations have been developed to support Māori student success. The objective of this study is to encourage the development of increased self-confidence for Māori rangatahi and to promote the continuation of lifelong learning.
When Māori students are supported both at school and in the home they are more likely to achieve educational success, particularly at secondary school level. Similarly, at tertiary level study; students who graduate with a completed degree qualification are likely to have had positive support and successful role models, they are likely to be secure within their own identity and wh!nau network. Māori students that successfully complete tertiary study are more likely to have positive attitudes to learning and to achieving; knowing how to access support and feeling confident in their efforts.
The key to this study is the link between successful completion of secondary school and the follow-on to successful tertiary study. When Māori students are supported appropriately in the development of their identity their confidence soon follows. This support would ideally come from wh!nau in the home and the school. When Māori students are confident in their learning journeys through high levels of confidence in identity they are more likely to persevere under pressure and despite setbacks.
Influencing factors to developing self-confidence for Māori students include awareness of Te Reo Māori and Tikanga Māori, responsibility at home, responsibility at school and the positive influence of role models. The study then concludes by providing recommendations for learners, educators and wh!nau to support the educational achievement of their tamariki.

year: 2013