http://hdl.handle.net/10204/3071 2013-05-21T18:05:43Z 2013-05-21T18:05:43Z Setshedi, KZ Bhaumik, M Songwane, S nyango, MS Maity, A http://hdl.handle.net/10204/6743 2013-05-21T11:48:15Z 2013-01-01T00:00:00Z

Title: Exfoliated polypyrrole-organically modified montmorillonite clay nanocomposite as a potential adsorbent for Cr (VI) removal Authors: Setshedi, KZ; Bhaumik, M; Songwane, S; nyango, MS; Maity, A Abstract: Exfoliated polypyrrole-organically modified montmorillonite clay nanocomposite (PPy OMMT NC), was prepared as a potential adsorbent, via in situ polymerization of pyrrole monomer for adsorption of toxic Cr(VI) from aqueous solution. The WAXD and SAXS results indicated that the clay sheets were exfoliated in the prepared nanocomposite. HR-TEM results showed good dispersion of the clay into the polymer matrix. The presence of the PPy polymer in the nanocomposite and adsorption of Cr(VI) onto the nanocomposite were confirmed using ATR-FTIR. Using the BET method, an improved surface area was observed for the PPy-OMMT NC compared to native clay. Batch adsorption studies whereby the pH, initial Cr(VI) concentration, sorbent dosage and temperature were varied, revealed that Cr(VI) adsorption process was rapid, spontaneous in nature and favoured with increased temperature at pH 2. The kinetic data fitted well to the pseudo second order kinetic model while the equilibrium data was satisfactorily described by the Langmuir isotherm. The Langmuir maximum adsorption capacity of Cr(VI) onto PPy-OMMT NC at pH 2.0 was found to be 112.3, 119.34, 176.2 and 209.6 mg/g at 292 K, 298 K, 308 K and 318 K, respectively. The selective adsorption of Cr(VI) was demonstrated in binary adsorption systems with co-existing ions. Moreover, desorption experiments revealed that the nanocomposite can be reused effectively for two consecutive adsorption–desorption cycles without any loss of its original capacity. Groundwater test results showed that the nanocomposite is a potential adsorbent for Cr(VI) ion removal from contaminated water sources. Description: Copyright: 2013 Elsevier. This is an ABSTRACT ONLY. The definite version is published in Chemical Engineering Journal, vol. 222, pp186-197

2013-01-01T00:00:00Z Schachtschneider, K http://hdl.handle.net/10204/6740 2013-05-21T10:36:30Z 2012-03-01T00:00:00Z

Title: Mitigating health problems associated with AMD in South Africa Authors: Schachtschneider, K Abstract: Acid mine drainage (AMD) is a serious threat to water quality in South Africa. Questions are being asked to South African government leaders as to what they are doing to mitigate the effects that South Africa’s mining industry is having on communities’ water supply and the water table. The CSIR has developed a novel process to reclaim high-quality precipitated calcium carbonate (PCC) from calcium-rich industrial solid waste. Calcium carbonate can be used to prevent AMD from becoming too acidic, as it has the effect of lowering water's pH level. Description: Copyright: 2012 Malnor Publications. This is an ABSTRACT ONLY. The definitive version is published in Government Digest, Vol. 31 (9,)pp 28-29

2012-03-01T00:00:00Z Funke, N Claassen, M Nienaber, S http://hdl.handle.net/10204/6738 2013-05-21T10:32:52Z 2013-05-01T00:00:00Z

Title: Development and uptake of scenarios to support water resources planning, development and management: examples from South Africa Authors: Funke, N; Claassen, M; Nienaber, S Abstract: The international agenda on water resources development reflects societal needs, political agendas, economic realities and the state of resources. The industrial revolution, which started in the 18th century, brought social and economic prosperity but also marked a major shift in humanity’s impact on the earth’s systems. This shift is now referred to as the Anthropocene, where humans have brought such vast and unprecedented changes to the planet that this era represents a new geological time interval. Societal needs have shifted since the 1940s from a need for modest food production to a need for increased agricultural productivity that has been met by high yield crops, the use of pesticides, the application of fertiliser and advanced agricultural techniques. This development has averted food shortages, but has also resulted in humanity having to pay a heavy price in terms of increased water use and energy consumption, as well as environmental degradation. Description: Copyright: Intech publishing, New York, USA

2013-05-01T00:00:00Z du Preez, M http://hdl.handle.net/10204/6737 2013-05-21T10:32:15Z 2010-09-01T00:00:00Z

Title: Health impact assessment of Solar Disinfection (SODIS) of drinking water in three African countries Authors: du Preez, M Abstract: Access to affordable, safe and sufficient quantities of water is fundamental to health and dignity of all humans. However, in 2006 an estimated 1.1 billion people still had no access to safe water and 2.6 billion lacked access to basic sanitation (UNICEF, 2010). An estimated 94% of the diarrhoeal burden of disease is attributable to the environment, and associated with risk factors such as unsafe drinking water, lack of sanitation and poor hygiene (Prüss-Üstün and Corvalán, 2006). Water contaminated with waterborne pathogens has a direct and profound negative effect on human health and consequently livelihoods, in the developed and developing world. The immediate adverse health effects of ingesting enteric waterborne pathogens mostly manifest in the form of diarrhoea. Globally diarrhoea ranks as the second largest cause of morbidity (UNICEF/WHO, 2009). One in five deaths in children is caused by diarrhoea bringing the number to a staggering 1.5 million children each year (UNICEF/WHO, 2009). Young children are impacted the most and for those infected with the human immunodeficiency virus (HIV) who have developed acquired immunodeficiency syndrome (AIDS), diarrhoea can be prolonged and severe and can ultimately cause death (USAID/BASIC, 2007). Solar disinfection (SODIS) refers to disinfection of water in transparent plastic bottles using sunlight. The effect of SODIS on diarrhoea in children was determined in South Africa (January, 2007 to December 2008), Kenya (July 2007 to March 2009) and Zimbabwe (June 2009 to November 2009). Based on information of census data and accessibility, peri-urban and rural areas with different socio-economic levels and water sources were selected as study areas. This thesis describes the rationale, methods and findings of the first scientific objective “Health impact assessments in three African countries.” The author was responsible for the overall coordination of the three African studies based on the protocol of the health impact assessments she developed during the proposal development phase. The health impact assessments were undertaken in South Africa by the Council for Scientific and Industrial Research (CSIR), and two non-governmental organisations (NGOs), the Institute for Water and Sanitation Development (IWSD) in Zimbabwe and the International Community for the Relief of Starvation and Suffering (ICROSS) in Kenya. Description: A thesis submitted to the Department of Physiology & Medical Physics, Royal College of Surgeons in Ireland, in fulfilment of the requirements for the degree of Doctor of Philosophy

2010-09-01T00:00:00Z