Mini-review on the use of liquid membranes in the extraction of platinum group metals from mining and metal refinery wastewaters/side-streams
- Moyo, Francis, Tandlich, Roman
- Authors: Moyo, Francis , Tandlich, Roman
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/75960 , vital:30487 , DOI: 10.4172/2155-6199.1000228
- Description: The current mini-review focuses on the use of liquid membranes in the platinum group metal (PGM/PGMs) extraction from various types of wastewaters to prevent environmental pollution; and for the metal recovery to address the scarcity of the PGMs in the industrial cycles. The bulk liquid membranes have been used to the extracted PGMs from the (acidic) aqueous media with recoveries of up to 96.3 ± 2.5% of the original PGM amount. The extraction time generally ranges from 2 to 24 hours. The bulk membrane liquid in the PGM extraction will depend on the covalent structure of the extractant, the feed phase PGM concentration and the complex of the PGM in question that is actually extracted from the aqueous environment. The advantages of this type of liquid membrane include its operational simplicity, but the disadvantages include limited possibility to improve the extraction performance of the system. Literature data are encouraging as they indicate that extraction of PGMs from mining and metal-refinery side-streams does not suffer from interference from metal contaminants that are commonly found in the mining and metal refinery side-streams, e.g. iron. Thus further research should focus on the application of ELM to extraction of PGMs from said wastewaters and major research drive should focus on the use of the Taylorvortex column and the non-Newtonian ELMs. With the supported liquid membranes, 78-82% of the original PGM content could be recovered from model side-streams. The selectivity of the extraction for individual PGMs can be controlled by the extractant used.
- Full Text:
- Date Issued: 2014
- Authors: Moyo, Francis , Tandlich, Roman
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/75960 , vital:30487 , DOI: 10.4172/2155-6199.1000228
- Description: The current mini-review focuses on the use of liquid membranes in the platinum group metal (PGM/PGMs) extraction from various types of wastewaters to prevent environmental pollution; and for the metal recovery to address the scarcity of the PGMs in the industrial cycles. The bulk liquid membranes have been used to the extracted PGMs from the (acidic) aqueous media with recoveries of up to 96.3 ± 2.5% of the original PGM amount. The extraction time generally ranges from 2 to 24 hours. The bulk membrane liquid in the PGM extraction will depend on the covalent structure of the extractant, the feed phase PGM concentration and the complex of the PGM in question that is actually extracted from the aqueous environment. The advantages of this type of liquid membrane include its operational simplicity, but the disadvantages include limited possibility to improve the extraction performance of the system. Literature data are encouraging as they indicate that extraction of PGMs from mining and metal-refinery side-streams does not suffer from interference from metal contaminants that are commonly found in the mining and metal refinery side-streams, e.g. iron. Thus further research should focus on the application of ELM to extraction of PGMs from said wastewaters and major research drive should focus on the use of the Taylorvortex column and the non-Newtonian ELMs. With the supported liquid membranes, 78-82% of the original PGM content could be recovered from model side-streams. The selectivity of the extraction for individual PGMs can be controlled by the extractant used.
- Full Text:
- Date Issued: 2014
Sanitation policy and prevention of environmental contamination in South Africa
- Hoossein, Shafick, Whittington-Jones, Kevin J, Tandlich, Roman
- Authors: Hoossein, Shafick , Whittington-Jones, Kevin J , Tandlich, Roman
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/76834 , vital:30628 , DOI:10.30638/eemj.2014.141
- Description: Prior to 1994, 21 million people were without access to sanitation in South Africa. Progress towards the backlog elimination started after 1994, but was slow-paced. From 1994 until 2011, the sanitation backlog has been decreased by between 29.8 and 79.2 % from the 1994 levels, depending on the province. Mechanisms were created for implementation of sanitation projects, but this was marginally successful and risk of environmental pollution from sanitation persisted. The period between 2009 and present day seemed to have brought on a significant fast-tracking of sanitation project around South Africa. This coincides with the transfer of oversight and partial implementation responsibility to the Department of Human Settlement and the launch of the Rural Household Infrastructure Programme. It also originated from the integrated programmes which drew in input from all stakeholders at the national and local government levels. Limitations still exist in maintenance and sanitation skills’ portfolio of some local municipalities, mainly in the Eastern Cape and Limpopo Province. However, the present status is still in partial conflict with government aims, legislation and policies. Novel tools such as the Technology Assessment and the Environmental Technology Assessment will have to be implemented in the sanitation decision-making and the novel strategies for skills development will have to be devised. If sufficient maintenance skills are developed in a local municipal area, then this will prevent negative environmental effects and results in lowered sanitation-related environmental contamination. Improvement in can be expected from the new national Department of Water Affairs and Sanitation.
- Full Text: false
- Date Issued: 2014
- Authors: Hoossein, Shafick , Whittington-Jones, Kevin J , Tandlich, Roman
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/76834 , vital:30628 , DOI:10.30638/eemj.2014.141
- Description: Prior to 1994, 21 million people were without access to sanitation in South Africa. Progress towards the backlog elimination started after 1994, but was slow-paced. From 1994 until 2011, the sanitation backlog has been decreased by between 29.8 and 79.2 % from the 1994 levels, depending on the province. Mechanisms were created for implementation of sanitation projects, but this was marginally successful and risk of environmental pollution from sanitation persisted. The period between 2009 and present day seemed to have brought on a significant fast-tracking of sanitation project around South Africa. This coincides with the transfer of oversight and partial implementation responsibility to the Department of Human Settlement and the launch of the Rural Household Infrastructure Programme. It also originated from the integrated programmes which drew in input from all stakeholders at the national and local government levels. Limitations still exist in maintenance and sanitation skills’ portfolio of some local municipalities, mainly in the Eastern Cape and Limpopo Province. However, the present status is still in partial conflict with government aims, legislation and policies. Novel tools such as the Technology Assessment and the Environmental Technology Assessment will have to be implemented in the sanitation decision-making and the novel strategies for skills development will have to be devised. If sufficient maintenance skills are developed in a local municipal area, then this will prevent negative environmental effects and results in lowered sanitation-related environmental contamination. Improvement in can be expected from the new national Department of Water Affairs and Sanitation.
- Full Text: false
- Date Issued: 2014
Sorption of hydrophobic organic compounds on natural sorbents and organoclays from aqueous and non-aqueous solutions: a mini-review
- Moyo, Francis, Tandlich, Roman, Wilhelmi, Brendan S, Balaz, Stefan
- Authors: Moyo, Francis , Tandlich, Roman , Wilhelmi, Brendan S , Balaz, Stefan
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/71614 , vital:29925 , https://doi.org/10.3390/ijerph110505020
- Description: Renewed focus on the sorption of hydrophobic organic chemicals (HOCs) onto mineral surfaces and soil components is required due to the increased and wider range of organic pollutants being released into the environment. This mini-review examines the possibility of the contribution and mechanism of HOC sorption onto clay mineral sorbents such as kaolinite, and soil organic matter and the possible role of both in the prevention of environmental contamination by HOCs. Literature data indicates that certain siloxane surfaces can be hydrophobic. Therefore soils can retain HOCs even at low soil organic levels and the extent will depend on the structure of the pollutant and the type and concentration of clay minerals in the sorbent. Clay minerals are wettable by nonpolar solvents and so sorption of HOCs onto them from aqueous and non-aqueous solutions is possible. This is important for two reasons: firstly, the movement and remediation of soil environments will be a function of the concentration and type of clay minerals in the soil. Secondly, low-cost sorbents such as kaolinite and expandable clays can be added to soils or contaminated environments as temporary retention barriers for HOCs. Inorganic cations sorbed onto the kaolinite have a strong influence on the rate and extent of sorption of hydrophobic organic pollutants onto kaolinite. Structural sorbate classes that can be retained by the kaolinite matrix are limited by hydrogen bonding between hydroxyl groups of the octahedral alumosilicate sheet and the tetrahedral sheet with silicon. Soil organic carbon plays a key role in the sorption of HOCs onto soils, but the extent will be strongly affected by the structure of the organic soil matter and the presence of soot. Structural characterisation of soil organic matter in a particular soil should be conducted during a particular contamination event. Contamination by mining extractants and antibiotics will require renewed focus on the use of the QSAR approaches in the context of the sorption of HOCs onto clay minerals from aqueous and non-aqueous solutions.
- Full Text:
- Date Issued: 2014
- Authors: Moyo, Francis , Tandlich, Roman , Wilhelmi, Brendan S , Balaz, Stefan
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/71614 , vital:29925 , https://doi.org/10.3390/ijerph110505020
- Description: Renewed focus on the sorption of hydrophobic organic chemicals (HOCs) onto mineral surfaces and soil components is required due to the increased and wider range of organic pollutants being released into the environment. This mini-review examines the possibility of the contribution and mechanism of HOC sorption onto clay mineral sorbents such as kaolinite, and soil organic matter and the possible role of both in the prevention of environmental contamination by HOCs. Literature data indicates that certain siloxane surfaces can be hydrophobic. Therefore soils can retain HOCs even at low soil organic levels and the extent will depend on the structure of the pollutant and the type and concentration of clay minerals in the sorbent. Clay minerals are wettable by nonpolar solvents and so sorption of HOCs onto them from aqueous and non-aqueous solutions is possible. This is important for two reasons: firstly, the movement and remediation of soil environments will be a function of the concentration and type of clay minerals in the soil. Secondly, low-cost sorbents such as kaolinite and expandable clays can be added to soils or contaminated environments as temporary retention barriers for HOCs. Inorganic cations sorbed onto the kaolinite have a strong influence on the rate and extent of sorption of hydrophobic organic pollutants onto kaolinite. Structural sorbate classes that can be retained by the kaolinite matrix are limited by hydrogen bonding between hydroxyl groups of the octahedral alumosilicate sheet and the tetrahedral sheet with silicon. Soil organic carbon plays a key role in the sorption of HOCs onto soils, but the extent will be strongly affected by the structure of the organic soil matter and the presence of soot. Structural characterisation of soil organic matter in a particular soil should be conducted during a particular contamination event. Contamination by mining extractants and antibiotics will require renewed focus on the use of the QSAR approaches in the context of the sorption of HOCs onto clay minerals from aqueous and non-aqueous solutions.
- Full Text:
- Date Issued: 2014
The "old-new" challenges of water, sanitation and bioremediation in developing countries
- Authors: Tandlich, Roman
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/75982 , vital:30489 , DOI: 10.4172/2155-6199.1000e152
- Description: Developing countries face challenges in the development of infrastructure and population growth. These lead to “side-effects" such as uncontrolled urbanization and the fact that basic services such as water and sanitation are lagging behind the actual needs on the ground. Historical challenges, lack of skilled staff and often lack of sustained funding are some of the reasons for the status quo. Extent of water and sanitation coverage often forces national and local governments to install the minimum-standard solutions, e.g. the ventilated improved pit latrines. This improves the public health status in the short-term, but causes problem in the long run due to the lack of regular maintenance such as through lack emptying of pits. Sometimes, construction of these facilities is of inferior standard. Pits are often built without lining or zero consideration is given to the local conditions in terms of soil properties, water table and the number of toilet users.
- Full Text:
- Date Issued: 2014
- Authors: Tandlich, Roman
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/75982 , vital:30489 , DOI: 10.4172/2155-6199.1000e152
- Description: Developing countries face challenges in the development of infrastructure and population growth. These lead to “side-effects" such as uncontrolled urbanization and the fact that basic services such as water and sanitation are lagging behind the actual needs on the ground. Historical challenges, lack of skilled staff and often lack of sustained funding are some of the reasons for the status quo. Extent of water and sanitation coverage often forces national and local governments to install the minimum-standard solutions, e.g. the ventilated improved pit latrines. This improves the public health status in the short-term, but causes problem in the long run due to the lack of regular maintenance such as through lack emptying of pits. Sometimes, construction of these facilities is of inferior standard. Pits are often built without lining or zero consideration is given to the local conditions in terms of soil properties, water table and the number of toilet users.
- Full Text:
- Date Issued: 2014
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