Synthesis, characterization and performance of adsorbents for mercury vapor removal

Mercury pollution is a growing concern due to its toxicity, volatility, and bioaccumulation in the environment. The main and most problematic source of mercury emission comes from the coal-fired power plants and gas processing activities. Hence, mercury needs to be removed and adsorption has been pr...

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Main Author:	Johari, Khairiraihanna
Format:	Thesis
Language:	English
Published:	2015
Subjects:	TP Chemical technology
Online Access:	http://eprints.utm.my/id/eprint/54887/1/KhairiraihannaJohariPFChE2015.pdf
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spelling	my-utm-ep.548872020-11-11T07:25:51Z Synthesis, characterization and performance of adsorbents for mercury vapor removal 2015-06 Johari, Khairiraihanna TP Chemical technology Mercury pollution is a growing concern due to its toxicity, volatility, and bioaccumulation in the environment. The main and most problematic source of mercury emission comes from the coal-fired power plants and gas processing activities. Hence, mercury needs to be removed and adsorption has been proven to be an excellent method due to easiness of operation and efficiency. In this study, coconut husk such as coconut pith and fiber were used as alternative low-cost adsorbents in exchange to the existing conventional elemental mercury (Hgo) adsorbents. The potential use of coconut based-adsorbents for elemental mercury removal from gas streams has not yet been fully explored due to lack of research in this regard. This research focused on synthesis and modifications of coconut husk such as surface, carbonization and sulfurization treatments in order to enhance elemental mercury adsorption performance. The adsorbents were characterized using proximate analysis, scanning electron microscope (SEM), Fourier transform infrared (FTIR) spectroscopy, nitrogen adsorption/desorption (NAD), carbon-hydrogennitrogen- sulfur (CHNS) analysis and X-ray photoelectron spectroscopy (XPS) measurement. The Hgo adsorption experiments were conducted using a conventional flow type packed-bed reactor system with nitrogen as carrier gas. The results show that the chemical, physical, morphological and spectral properties of the adsorbents were greatly influenced by the modification methods used. Adsorbents obtained through carbonization and sulfurization treatments produced the best Hgo adsorption capacity. The experimental data exhibited that the increase of thermal carbonization up to 900 oC, resulted in high adsorption capacity of 6067.49 µg/g. The sulfurization at lower temperature (i.e. CPS300) resulted in the highest adsorption capacity (26077.69 µg/g). Enhancement in Hgo adsorption capacity might due to the higher sulfur compounds on the surface which acts as active site towards elemental mercury. The adsorption data revealed that the adsorbent with larger equilibrium adsorption capacity possessed poor adsorption reaction kinetics and diffusion process. This study also revealed that the char adsorbent could sustain Hgo adsorption capacity over multiple regeneration cycles. However, sulfurized-char is non-regenerative adsorbent, which can be utilized for longer adsorption process. Finally, the present findings indicate that the coconut husk can be potential low-cost elemental mercury adsorbents by applying appropriate modifications such as carbonization and sulfurization treatments. In addition, the utilization of coconut husks can reduce waste disposal problems and thus improving environmental quality and sustainability. 2015-06 Thesis http://eprints.utm.my/id/eprint/54887/ http://eprints.utm.my/id/eprint/54887/1/KhairiraihannaJohariPFChE2015.pdf application/pdf en public http://dms.library.utm.my:8080/vital/access/manager/Repository/vital:95641 phd doctoral Universiti Teknologi Malaysia, Faculty of Chemical Engineering Faculty of Chemical Engineering
institution	Universiti Teknologi Malaysia
collection	UTM Institutional Repository
language	English
topic	TP Chemical technology
spellingShingle	TP Chemical technology Johari, Khairiraihanna Synthesis, characterization and performance of adsorbents for mercury vapor removal
description	Mercury pollution is a growing concern due to its toxicity, volatility, and bioaccumulation in the environment. The main and most problematic source of mercury emission comes from the coal-fired power plants and gas processing activities. Hence, mercury needs to be removed and adsorption has been proven to be an excellent method due to easiness of operation and efficiency. In this study, coconut husk such as coconut pith and fiber were used as alternative low-cost adsorbents in exchange to the existing conventional elemental mercury (Hgo) adsorbents. The potential use of coconut based-adsorbents for elemental mercury removal from gas streams has not yet been fully explored due to lack of research in this regard. This research focused on synthesis and modifications of coconut husk such as surface, carbonization and sulfurization treatments in order to enhance elemental mercury adsorption performance. The adsorbents were characterized using proximate analysis, scanning electron microscope (SEM), Fourier transform infrared (FTIR) spectroscopy, nitrogen adsorption/desorption (NAD), carbon-hydrogennitrogen- sulfur (CHNS) analysis and X-ray photoelectron spectroscopy (XPS) measurement. The Hgo adsorption experiments were conducted using a conventional flow type packed-bed reactor system with nitrogen as carrier gas. The results show that the chemical, physical, morphological and spectral properties of the adsorbents were greatly influenced by the modification methods used. Adsorbents obtained through carbonization and sulfurization treatments produced the best Hgo adsorption capacity. The experimental data exhibited that the increase of thermal carbonization up to 900 oC, resulted in high adsorption capacity of 6067.49 µg/g. The sulfurization at lower temperature (i.e. CPS300) resulted in the highest adsorption capacity (26077.69 µg/g). Enhancement in Hgo adsorption capacity might due to the higher sulfur compounds on the surface which acts as active site towards elemental mercury. The adsorption data revealed that the adsorbent with larger equilibrium adsorption capacity possessed poor adsorption reaction kinetics and diffusion process. This study also revealed that the char adsorbent could sustain Hgo adsorption capacity over multiple regeneration cycles. However, sulfurized-char is non-regenerative adsorbent, which can be utilized for longer adsorption process. Finally, the present findings indicate that the coconut husk can be potential low-cost elemental mercury adsorbents by applying appropriate modifications such as carbonization and sulfurization treatments. In addition, the utilization of coconut husks can reduce waste disposal problems and thus improving environmental quality and sustainability.
format	Thesis
qualification_name	Doctor of Philosophy (PhD.)
qualification_level	Doctorate
author	Johari, Khairiraihanna
author_facet	Johari, Khairiraihanna
author_sort	Johari, Khairiraihanna
title	Synthesis, characterization and performance of adsorbents for mercury vapor removal
title_short	Synthesis, characterization and performance of adsorbents for mercury vapor removal
title_full	Synthesis, characterization and performance of adsorbents for mercury vapor removal
title_fullStr	Synthesis, characterization and performance of adsorbents for mercury vapor removal
title_full_unstemmed	Synthesis, characterization and performance of adsorbents for mercury vapor removal
title_sort	synthesis, characterization and performance of adsorbents for mercury vapor removal
granting_institution	Universiti Teknologi Malaysia, Faculty of Chemical Engineering
granting_department	Faculty of Chemical Engineering
publishDate	2015
url	http://eprints.utm.my/id/eprint/54887/1/KhairiraihannaJohariPFChE2015.pdf
_version_	1747817747878772736

Synthesis, characterization and performance of adsorbents for mercury vapor removal

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