Non-stoichiometric fibrous apatite for heavy metal ion capture
In this study, two different methods were used to synthesis hydroxyapatite (HA, Ca10(PO4)6(OH)2). Fibrous HA was synthesised by hydrothermal reaction and HA powders were obtained from high temperature solid state reaction. Kinetics and thermodynamics of lead sorption from aqueous lead nitrate sol...
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| Other Authors: | |
| Format: | Final Year Project (FYP) |
| Language: | English |
| Published: |
2009
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| Online Access: | http://hdl.handle.net/10356/15376 |
| _version_ | 1811689926949863424 |
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| author | Tan, Amos Zhong Min. |
| author2 | Srinivasan Madhavi |
| author_facet | Srinivasan Madhavi Tan, Amos Zhong Min. |
| author_sort | Tan, Amos Zhong Min. |
| collection | NTU |
| description | In this study, two different methods were used to synthesis hydroxyapatite (HA,
Ca10(PO4)6(OH)2). Fibrous HA was synthesised by hydrothermal reaction and HA powders
were obtained from high temperature solid state reaction. Kinetics and thermodynamics of
lead sorption from aqueous lead nitrate solutions with initial lead concentration of 2590 ppm
by fibrous HA and HA powders were investigated for different durations, between 1-336
hours at various temperatures of 23°C, 50°C and 80°C.
It was deduced by Rietveld analysis that the sorption capacities of both HA materials
increased with the increase in temperature through the growing proportions of
hydroxypyromorphite (HP), Pb10(PO4)6(OH)2. Fibrous HA displayed better performance in
better lead uptake capabilities due to their higher solubility, lower crystallinity and oriented
crystals as compared to HA powders. The maximum sorption capacity of fibrous HA for Pb2+
ions at 80°C for 240h was 2.42 mmol/g relative to 0.67 mmol/g for the HA powders at the
same temperature, with 2.50 mmol/g being the maximum possible amount of lead sorbed by
HA.
Fresh HA materials and samples previously exposed to lead were also analyzed via scanning
electron microscopy (SEM) and the detection of HP reinforced the hypothesis that its
formation is the end of a kinetic process in which the HP crystals are continuously dissolved
and recrystallised in order to form more stable structures with higher lead content.
The first-order kinetic model was used to describe the kinetic data, and the data constants
were evaluated. The activation energy was also calculated from fitting the Arrhenius equation
with the graph of ln K against temperature inverse. Fibrous HA has activation energy of
54.92kg/mol.
Hence, fibrous HA can be considered as a potential adsorbent for the remediation of lead ions
in contaminated industrial wastewaters. |
| first_indexed | 2024-10-01T05:55:52Z |
| format | Final Year Project (FYP) |
| id | ntu-10356/15376 |
| institution | Nanyang Technological University |
| language | English |
| last_indexed | 2024-10-01T05:55:52Z |
| publishDate | 2009 |
| record_format | dspace |
| spelling | ntu-10356/153762023-03-04T15:34:55Z Non-stoichiometric fibrous apatite for heavy metal ion capture Tan, Amos Zhong Min. Srinivasan Madhavi School of Materials Science and Engineering DRNTU::Engineering In this study, two different methods were used to synthesis hydroxyapatite (HA, Ca10(PO4)6(OH)2). Fibrous HA was synthesised by hydrothermal reaction and HA powders were obtained from high temperature solid state reaction. Kinetics and thermodynamics of lead sorption from aqueous lead nitrate solutions with initial lead concentration of 2590 ppm by fibrous HA and HA powders were investigated for different durations, between 1-336 hours at various temperatures of 23°C, 50°C and 80°C. It was deduced by Rietveld analysis that the sorption capacities of both HA materials increased with the increase in temperature through the growing proportions of hydroxypyromorphite (HP), Pb10(PO4)6(OH)2. Fibrous HA displayed better performance in better lead uptake capabilities due to their higher solubility, lower crystallinity and oriented crystals as compared to HA powders. The maximum sorption capacity of fibrous HA for Pb2+ ions at 80°C for 240h was 2.42 mmol/g relative to 0.67 mmol/g for the HA powders at the same temperature, with 2.50 mmol/g being the maximum possible amount of lead sorbed by HA. Fresh HA materials and samples previously exposed to lead were also analyzed via scanning electron microscopy (SEM) and the detection of HP reinforced the hypothesis that its formation is the end of a kinetic process in which the HP crystals are continuously dissolved and recrystallised in order to form more stable structures with higher lead content. The first-order kinetic model was used to describe the kinetic data, and the data constants were evaluated. The activation energy was also calculated from fitting the Arrhenius equation with the graph of ln K against temperature inverse. Fibrous HA has activation energy of 54.92kg/mol. Hence, fibrous HA can be considered as a potential adsorbent for the remediation of lead ions in contaminated industrial wastewaters. Bachelor of Engineering (Materials Engineering) 2009-04-28T02:17:53Z 2009-04-28T02:17:53Z 2009 2009 Final Year Project (FYP) http://hdl.handle.net/10356/15376 en 43 p. application/pdf |
| spellingShingle | DRNTU::Engineering Tan, Amos Zhong Min. Non-stoichiometric fibrous apatite for heavy metal ion capture |
| title | Non-stoichiometric fibrous apatite for heavy metal ion capture |
| title_full | Non-stoichiometric fibrous apatite for heavy metal ion capture |
| title_fullStr | Non-stoichiometric fibrous apatite for heavy metal ion capture |
| title_full_unstemmed | Non-stoichiometric fibrous apatite for heavy metal ion capture |
| title_short | Non-stoichiometric fibrous apatite for heavy metal ion capture |
| title_sort | non stoichiometric fibrous apatite for heavy metal ion capture |
| topic | DRNTU::Engineering |
| url | http://hdl.handle.net/10356/15376 |
| work_keys_str_mv | AT tanamoszhongmin nonstoichiometricfibrousapatiteforheavymetalioncapture |