http://hdl.handle.net/10204/941 2013-05-23T15:16:35Z http://hdl.handle.net/10204/6743 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 http://hdl.handle.net/10204/6738 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 http://hdl.handle.net/10204/6699 Title: An overview of the role of social capital in development processes Authors: Marais, MA Abstract: The sustainability of ICT for Development (ICT4D) initiatives, and indeed any development initiative, depends on many different factors that has been summarised in terms of financial, social, institutional, technological, and environmental sustainability. This complexity has led to researchers suggesting bricolage approaches that try to make do with the resources at hand, improvise and muddle through to develop local and contextual solutions. An important factor in this kind of approach is the role of relationships, particularly as evidenced in social networks of contact consisting of strong and weak ties, that has been called social capital and linking or bridging capital. The concept of social capital has been shown to influence many different processes in development. In the use of resources the capability approach refers to the influence of social capital on the conversion of commodities, technologies and resources by a person into situated use. The adoption of an innovation is also influenced by social capital, especially via the important role that is played by trust. In the design of development interventions, various types of theories of change have been articulated and the role of social capital in some of these theories is investigated. This paper aims to summarise and analyse the influence of social capital on development processes as seen from the different perspectives mentioned. In terms of development, a fundamental insight is that social capital plays a role in mediating development outcomes through embedded and autonomous social relations that can resolve social problems at macro and micro levels. Social capital also consists in crucial cross-level linkages that need to exist to enable top-down initiatives to meet bottom-up development. Description: CIRN 2012 Community Informatics Conference: 'Ideals meet Reality', Monash Centre Prato Italy, 7-9 Nov 2012. Published in The Academia 2012-11-01T00:00:00Z http://hdl.handle.net/10204/6692 Title: Energy from wastewater - a feasibility study and guide for: Technology developers and researchers, industry and wastewater generators and policy makers Authors: Burton, S; Cohen, B; Harrison, S; Pather-Elias, S; Stafford, W; Van Hille, R; Von Blottnitz, H Abstract: This guide is based on a study funded by the Water Research Commission with the purpose of determining the feasibility of developing technologies for energy recovery from wastewater. A full technical report is available for further reference (WRC report no 1732/1/09). The availability of clean, renewable fuels is well recognised to be core to sustainable economic growth. The use of wastewater as a renewable energy resource has been poorly exploited to date particularly in developing countries such as South Africa. Wastewaters as renewable sources of energy are valuable to supplement and/or replace non-renewable sources, reduce the environmental burden of conventional power generation and provide the added benefit of enhanced waste processing. The study reviewed the available literature and surveyed international and national practice in energy recovery from wastewater in order to identify the most significant potential for new research and innovation. A survey of potentials for energy from wastewater in South Africa served to identify which types of substrates are available in significant amounts. The project also included a set of case studies that show what factors to consider in developing energy from wastewater projects. Workshops were held to provide opportunities for consultation with stakeholders in the fields of wastewater treatment and technology development, in order to determine areas where technical and application problems might exist (WRC report no1732/1/09). This guide makes recommendations relevant to the R&D sector regarding recovery of energy from wastewater. It also seeks to provide information about directions which would be useful to South Africa’s research community by identifying areas where R&D are needed, and by highlighting areas to which the WRC might direct funding in future. Description: Copyright: 2009 South African Water Resource Commission. This is an ABSTRACT ONLY. The definitive version is published in WRC, Report No. TT 400/09. 2012-07-01T00:00:00Z