Reduction of chromium (VI) to chromium (III) using continuous emulsion liquid membrane

Recently, the application of emulsion liquid membrane (ELM) process as an alternative technology for solute separation is highlighted due to the simple operation of simultaneous extraction and stripping process. The most important aspects for a successful ELM process are liquid membrane formulation...

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Main Author:	Mohamed Noah, Norul Fatiha
Format:	Thesis
Language:	English
Published:	2019
Subjects:	TP Chemical technology
Online Access:	http://eprints.utm.my/id/eprint/92512/1/NorulFatihaPSChE2019.pdf.pdf
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spelling	my-utm-ep.925122021-09-30T15:11:22Z Reduction of chromium (VI) to chromium (III) using continuous emulsion liquid membrane 2019 Mohamed Noah, Norul Fatiha TP Chemical technology Recently, the application of emulsion liquid membrane (ELM) process as an alternative technology for solute separation is highlighted due to the simple operation of simultaneous extraction and stripping process. The most important aspects for a successful ELM process are liquid membrane formulation and emulsion stability. This study was carried out to investigate the liquid membrane formulation for the reduction of chromium (VI) to chromium (III) from electroplating wastewater using continuous ELM process (CELM). Liquid membrane system comprises of three liquid phases which are external (electroplating wastewater), organic liquid membrane and internal phase. Liquid membrane and internal phase were emulsified and dispersed into the external phase to be treated. The experimental work consisted of four major parts which were ELM component formulation, stability study of ELM in batch process, screening of parameters and optimization of chromium removal efficiency by response surface methodology (RSM) in continuous operation process and recovery of the chromium at optimum process conditions. The results show that the favourable conditions for liquid membrane formulation are 0.04 M TOMAC as a carrier, palm oil as a diluent and 0.1 M thiourea in 0.1 M sulfuric acid as a stripping agent. The best condition of stable water-in-oil (W/O) emulsion was obtained at 7000 rpm of homogenizer speed, 5% (w/v) Span 80 as surfactant and 1 minute of emulsifying time. Meanwhile, the most stable water-in-oil-in-water (W/O/W) emulsion obtained during the continuous process operation was at 350 rpm agitation speed, pH<5 of external phase and 1 to 5 of treat ratio. The optimization results by RSM show that 99% of chromium was extracted at 2.83 minutes of retention time, 342 rpm rotational speed and 1 to 5 of treat ratio. As a conclusion, about 81% of less-toxic chromium (III) has been recovered into the internal phase using 2.0 M thiourea in 2.0 M sulfuric acid as the stripping agent. The favourable process condition of the formulated membrane study was satisfactory and is suitable to treat wastewater as low as 20 ppm up to 200 ppm of chromium concentrations. This study reveals that CELM is a simple process and practical technology to remove chromium (VI) from industrial wastewater while solving the environmental problem simultaneously. 2019 Thesis http://eprints.utm.my/id/eprint/92512/ http://eprints.utm.my/id/eprint/92512/1/NorulFatihaPSChE2019.pdf.pdf application/pdf en public http://dms.library.utm.my:8080/vital/access/manager/Repository/vital:139239 phd doctoral Universiti Teknologi Malaysia Faculty of Engineering - School of Chemical & Energy Engineering
institution	Universiti Teknologi Malaysia
collection	UTM Institutional Repository
language	English
topic	TP Chemical technology
spellingShingle	TP Chemical technology Mohamed Noah, Norul Fatiha Reduction of chromium (VI) to chromium (III) using continuous emulsion liquid membrane
description	Recently, the application of emulsion liquid membrane (ELM) process as an alternative technology for solute separation is highlighted due to the simple operation of simultaneous extraction and stripping process. The most important aspects for a successful ELM process are liquid membrane formulation and emulsion stability. This study was carried out to investigate the liquid membrane formulation for the reduction of chromium (VI) to chromium (III) from electroplating wastewater using continuous ELM process (CELM). Liquid membrane system comprises of three liquid phases which are external (electroplating wastewater), organic liquid membrane and internal phase. Liquid membrane and internal phase were emulsified and dispersed into the external phase to be treated. The experimental work consisted of four major parts which were ELM component formulation, stability study of ELM in batch process, screening of parameters and optimization of chromium removal efficiency by response surface methodology (RSM) in continuous operation process and recovery of the chromium at optimum process conditions. The results show that the favourable conditions for liquid membrane formulation are 0.04 M TOMAC as a carrier, palm oil as a diluent and 0.1 M thiourea in 0.1 M sulfuric acid as a stripping agent. The best condition of stable water-in-oil (W/O) emulsion was obtained at 7000 rpm of homogenizer speed, 5% (w/v) Span 80 as surfactant and 1 minute of emulsifying time. Meanwhile, the most stable water-in-oil-in-water (W/O/W) emulsion obtained during the continuous process operation was at 350 rpm agitation speed, pH<5 of external phase and 1 to 5 of treat ratio. The optimization results by RSM show that 99% of chromium was extracted at 2.83 minutes of retention time, 342 rpm rotational speed and 1 to 5 of treat ratio. As a conclusion, about 81% of less-toxic chromium (III) has been recovered into the internal phase using 2.0 M thiourea in 2.0 M sulfuric acid as the stripping agent. The favourable process condition of the formulated membrane study was satisfactory and is suitable to treat wastewater as low as 20 ppm up to 200 ppm of chromium concentrations. This study reveals that CELM is a simple process and practical technology to remove chromium (VI) from industrial wastewater while solving the environmental problem simultaneously.
format	Thesis
qualification_name	Doctor of Philosophy (PhD.)
qualification_level	Doctorate
author	Mohamed Noah, Norul Fatiha
author_facet	Mohamed Noah, Norul Fatiha
author_sort	Mohamed Noah, Norul Fatiha
title	Reduction of chromium (VI) to chromium (III) using continuous emulsion liquid membrane
title_short	Reduction of chromium (VI) to chromium (III) using continuous emulsion liquid membrane
title_full	Reduction of chromium (VI) to chromium (III) using continuous emulsion liquid membrane
title_fullStr	Reduction of chromium (VI) to chromium (III) using continuous emulsion liquid membrane
title_full_unstemmed	Reduction of chromium (VI) to chromium (III) using continuous emulsion liquid membrane
title_sort	reduction of chromium (vi) to chromium (iii) using continuous emulsion liquid membrane
granting_institution	Universiti Teknologi Malaysia
granting_department	Faculty of Engineering - School of Chemical & Energy Engineering
publishDate	2019
url	http://eprints.utm.my/id/eprint/92512/1/NorulFatihaPSChE2019.pdf.pdf
_version_	1747818600051245056

Reduction of chromium (VI) to chromium (III) using continuous emulsion liquid membrane

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