Recovery of palladium from aqueous solution using surfactant mediated precipitation process

In recent years, the demand for precious metals has increased in most emerging countries. The precious metals are mainly used not only in jewellery but also in electrical devices, medical instruments and as catalysts. They can be primarily recovered not only from the ores but also secondary sources...

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Main Author:	Buhari, Junaidah
Format:	Thesis
Language:	English
Published:	2015
Subjects:	TP Chemical technology
Online Access:	http://eprints.utm.my/id/eprint/81041/1/JunaidahBuhariMFChE2015.pdf
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spelling	my-utm-ep.810412019-07-24T03:06:20Z Recovery of palladium from aqueous solution using surfactant mediated precipitation process 2015-10 Buhari, Junaidah TP Chemical technology In recent years, the demand for precious metals has increased in most emerging countries. The precious metals are mainly used not only in jewellery but also in electrical devices, medical instruments and as catalysts. They can be primarily recovered not only from the ores but also secondary sources like electronic wastes and spent catalysts. This research aimed to develop a method for the recovery of palladium (Pd) from synthetic and real Pd solutions using surfactant mediated precipitation process. The surfactant used was cetyltrimethylammonium bromide (CTAB), while the leaching agents used were hydrochloric acid (HCl), nitric acid (HNO3): sulphuric acid (H2SO4), hydrochloric acid (HCl): hydrogen peroxide (H2O2) and aqua regia. The real Pd solution was prepared using selected leaching agents and spent catalyst. The effect of process parameters such as leaching agent types, CTAB concentrations, Pd concentrations, temperature, and contact time on Pd recovery efficiency were studied. Comparative study between CTAB and other reducing agent (i.e. formic acid) was also carried out. The concentration of Pd was determined using atomic absorption spectroscopy (AAS), while the CTAB concentration was determined by the two-phase titration method. The experimental results show that the Pd recovery efficiency strongly depends on the CTAB and Pd concentrations. The increase of temperature resulted in lowering the Pd recovery efficiency. The precipitation process was relatively fast (less than 3 minutes). The Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS) analyses showed changes in CTAB functional groups after the precipitation process. The stoichiometry reaction between Pd and CTAB as given by the molar ratio of Pd to CTAB was 2. The results from the leaching process of spent catalyst using several leaching agents (i.e. HCl, HNO3:H2SO4, aqua regia) show that HCl as the leaching agent gave high selectivity towards Pd compared to other metals present in the spent catalyst. It was found that 85% Pd could be recovered from the real Pd solution (i.e. spent catalyst leaching solution) using 1 mM CTAB. 2015-10 Thesis http://eprints.utm.my/id/eprint/81041/ http://eprints.utm.my/id/eprint/81041/1/JunaidahBuhariMFChE2015.pdf application/pdf en public http://dms.library.utm.my:8080/vital/access/manager/Repository/vital:120316 masters Universiti Teknologi Malaysia, Faculty of Chemical and Energy Engineering Faculty of Chemical and Energy Engineering
institution	Universiti Teknologi Malaysia
collection	UTM Institutional Repository
language	English
topic	TP Chemical technology
spellingShingle	TP Chemical technology Buhari, Junaidah Recovery of palladium from aqueous solution using surfactant mediated precipitation process
description	In recent years, the demand for precious metals has increased in most emerging countries. The precious metals are mainly used not only in jewellery but also in electrical devices, medical instruments and as catalysts. They can be primarily recovered not only from the ores but also secondary sources like electronic wastes and spent catalysts. This research aimed to develop a method for the recovery of palladium (Pd) from synthetic and real Pd solutions using surfactant mediated precipitation process. The surfactant used was cetyltrimethylammonium bromide (CTAB), while the leaching agents used were hydrochloric acid (HCl), nitric acid (HNO3): sulphuric acid (H2SO4), hydrochloric acid (HCl): hydrogen peroxide (H2O2) and aqua regia. The real Pd solution was prepared using selected leaching agents and spent catalyst. The effect of process parameters such as leaching agent types, CTAB concentrations, Pd concentrations, temperature, and contact time on Pd recovery efficiency were studied. Comparative study between CTAB and other reducing agent (i.e. formic acid) was also carried out. The concentration of Pd was determined using atomic absorption spectroscopy (AAS), while the CTAB concentration was determined by the two-phase titration method. The experimental results show that the Pd recovery efficiency strongly depends on the CTAB and Pd concentrations. The increase of temperature resulted in lowering the Pd recovery efficiency. The precipitation process was relatively fast (less than 3 minutes). The Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS) analyses showed changes in CTAB functional groups after the precipitation process. The stoichiometry reaction between Pd and CTAB as given by the molar ratio of Pd to CTAB was 2. The results from the leaching process of spent catalyst using several leaching agents (i.e. HCl, HNO3:H2SO4, aqua regia) show that HCl as the leaching agent gave high selectivity towards Pd compared to other metals present in the spent catalyst. It was found that 85% Pd could be recovered from the real Pd solution (i.e. spent catalyst leaching solution) using 1 mM CTAB.
format	Thesis
qualification_level	Master's degree
author	Buhari, Junaidah
author_facet	Buhari, Junaidah
author_sort	Buhari, Junaidah
title	Recovery of palladium from aqueous solution using surfactant mediated precipitation process
title_short	Recovery of palladium from aqueous solution using surfactant mediated precipitation process
title_full	Recovery of palladium from aqueous solution using surfactant mediated precipitation process
title_fullStr	Recovery of palladium from aqueous solution using surfactant mediated precipitation process
title_full_unstemmed	Recovery of palladium from aqueous solution using surfactant mediated precipitation process
title_sort	recovery of palladium from aqueous solution using surfactant mediated precipitation process
granting_institution	Universiti Teknologi Malaysia, Faculty of Chemical and Energy Engineering
granting_department	Faculty of Chemical and Energy Engineering
publishDate	2015
url	http://eprints.utm.my/id/eprint/81041/1/JunaidahBuhariMFChE2015.pdf
_version_	1747818298567819264

Recovery of palladium from aqueous solution using surfactant mediated precipitation process

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