The Centre for Nanomaterials Science Research (CNSR) facilitates and supports individual and collaborative research in the Department of Applied Chemistry. Its members are mostly active academic staff members some of which affiliate with a number of professional organizations including the South African Chemical Institute, the Water Institute of Southern Africa, the South African Nanotechnology Initiative, the American Chemical Society and the Royal Society of Chemistry.
The CNSR at the University of Johannesburg was established in 2007 and consisted of four “Pillars” of research, all having a nanomaterials science foundation. While other nano-based activities exist within the University, these four pillars or Focus Areas represent the current strategic focus within the Faculty of Science. The primary aim of the CNSR is to highlight the nanomaterials expertise at the University of Johannesburg, while providing a platform for the high-level training of researchers in Materials Science.
The CNSR forms part of the DST/NRF Centre of Excellence in Strong Materials established by the NRF and Department of Science and Technology, which focuses on the synthesis, functionalisation, characterisation and applications of carbon-based nanomaterials i.e. carbon nanotubes and strong composites. Research staff in the CNSR is part of the academic staff of the University of Johannesburg, having several strong collaborations with other regional, national, and international institutions. On average the CNSR aims to fund two postdoctoral fellows and a senior research associate for three years, together with a number of postgraduate students.
Nanomaterials for water treatment
Nanomaterials for catalysis applications
Nanomaterials for sensors and photovoltaic applications
The Centre also supports research that involves analytical and electrochemistry with emphasis on water analysis and treatment.
Examples of on-going research in this group include projects on the synthesis of nano materials for catalysis, the synthesis and characterisation of aligned and N/B-doped multi- walled nanotubes chemical vapour deposition and the use of structurally modified nano materials in water purification. Much of this research is multidisciplinary and our postgraduate students gain wide range of experience ranging from synthetic techniques to electron microscopic characterisation. Other projects involve greener methods using microwave irradiation to synthesize nanocomposites materials incorporation doped carbon nanotubes and other metal nanoparticles. Some of the materials synthesized under this banner are listed below.
Activities in this area include fabrication and functionalization of commercial and in-house synthetic microfiltration-, ultrafiltration, nanofiltration and reverse osmosis membranes. The membranes are applied for removal of inorganics, organics and degradation of microbes in water. For degradation of organics and microbes in water, the membranes are impregnated with nanoparticles are im
The research activities involve electrospinning of synthetic and biopolymer solutions under applied voltage to produce nanofibers. The starting materials are synthetic- and biopolymers. The nanofibers are used as filters for removal of both inorganic and organic pollutants in water purification
Ceramics and nanomaterials
The prime research domain in this field is the development of silicon/carbon nanomaterials from carbonaceous waste material using sol-gel technology. These wastes include lignin, low-value coals, coal ash, medical waste, and polymers. The nanocomposite materials are then used for various applications.
Polymer composites and nanocomposites are widely used in the diversified area of material science. It has also been used to develop high energy thermal and packaging devices. The research focus in this division of nanomaterial research has been expanded to include the application of these composite/nanocomposites in the removal of heavy metals and organic pollutants based on adsorption chemistry.
Phosphorus Chemistry Research
The phosphorus chemistry research activities cover synthesis and biological evaluation of new bisphosphonate derivatives as anti-tumour and anti-viral agents. The bisphosphonate derivatives are important because of their anti-metastatic activity in cancer patients and their antiviral activity against HIV-1, HIV-2 and other retroviruses. Current projects focus on phosphorylation of single-walled and double-walled carbon nanotubes. The phosphorylated carbon nanotubes have also been applied in the treatment of radioactive waste and in the removal of toxic metal ions such as Cr(VI) and Hg(II). Currently the Department has joint anti-cancer research projects with the radiopharmaceutical unit at NECSA (Nuclear Energy Corporation of South Africa).
The water research group is one of the apex research niche areas of University of Johannesburg, namely the Water and Health Group (UJWHG). There are two main thrusts in the water research field. One focuses on the use of nanoporous polymers (alias nanosponges) for removing organic pollutants in water purification. The activities involve the synthesis of water-insoluble cyclodextrin- and calixarene-based polymers and their derivatives and testing of various forms of the materials, a collaborative with the industry partners, to remove organic pollutants. Nanosponges bind organic molecules in aqueous media, but release the same contaminants in organic media, which makes them ideal not only for this application but for chromatography, separation science, and for potential sensor applications. The UJWHG is a unique multidisciplinary organisation that involves engineering, health, and social science disciplines.
The electrochemistry research in the Department focuses on the following:
Electrochemical sensors and biosensors based on nanocomposite (dendrimer, gold nanoparticles, graphene and quantum dots) platforms for biomedical, water and environmental applications.
i) synthesis and photo/electro-characterisation of novel photoactive composite materials such as graphene, graphite, polymers/dendrimers, and other nanomaterials; ii) development of reactors for water treatment.
Application of electrochemistry in the analysis of organic, inorganic and natural products.
Current research involves development of chemical sensors for selected organic and inorganic water pollutants, aptamer biosensor for HIV protein detection, cholera biosensor, smart polymer based enzyme biosensors, exfoliated graphite based photoelectrochemical reactors for the removal of organics from water (water treatment), onsite electrochemical sensor for arsenic, among other metals.
Prof Omotayo Arotiba – Director
Centre for Nanomaterials Science Research (CNSR)
Tel.: +27 (0)11 559 6200
Fax: +27(0)11 559 6425
DST/Mintek Nanotechnology Innovation Centre (NIC)
The DST/Mintek is a national facility that is geographically spread across the country and was established at Mintek in 2007 by the Department of Science and Technology. The Mintek NIC activities are aimed at addressing national priorities highlighted by both the national nanotechnology strategy and national research and development (R&D) strategy. Importantly, the Mintek NIC structure was built on the foundation of the national system of innovations (NSI) to focus on driving South Africa’s transformation from resource-based economy towards knowledge based economy using nanotechnology. The Mintek NIC activities focus on a number of issues, including the development of research platforms, encouraging and promoting the formation of collaborative networks, addressing human capital development and bridging the “innovation chasm”.
The Department of Applied Chemistry collaborates with the DST/Mintek NIC in an attempt to develop nanomaterials-based solutions to solve problems relating to water treatment (Water Platform). The NIC operates under the umbrella of the Water and Health Research Group, which is a multidisciplinary sounding board within the University for water-related issues including the treatment, distribution, and social consequences of water resources. Its vision is to provide nanotechnology solutions for effective treatment of water to improve the quality of life of the people of South Africa. It seeks to address the objectives of the national Nanotechnology Strategy of South Africa in respect of improving the quality of life by pursuing research and development in water treatment utilizing nanotechnology and membrane technology.
The centre focuses on the use of polymeric materials and zeolites that can be used in a broad range of applications such as filter-beds and ion-exchange columns. These materials are broadly adaptable to different forms including granules, beads and films. Functionality is added by suitable immobilisation of nano-scale metal, inorganic and organic units. The centre’s main area of expertise is the application of synthesis and characterisation techniques to these “functional nanomaterials”. The functional nanomaterials are then applied to the detection, trapping, and destruction of water-borne pollutants, especially trace organic molecules. The centre works closely with local and international research institutions such as the University of the Western Cape, Durban University of Technology, and TU Delft in the Netherlands. It also has close links with science councils and water-bodies such as the Water Research Commission. Thirdly the participation from industrial partners like Rand-Water, ESKOM, and Industrial Urethanes allows us to develop the technology in tandem with the science. The centre has a strong focus on postgraduate student development, and short working visits by collaborating partners are encouraged.
The following Nanotechnology treatment systems are being developed:
Nanostructured polymeric adsorbent for capturing organics and heavy metals. Adsorption modules with low pressure drops for fast removal of organics and heavy metals.
Membrane supported nanocatalysts as treatment options for polluted water and wastewater. Total mineralisation and degradation of organic compounds using membrane supported nanocatalysts which have high degradation rates towards selected compounds are developed and fabricated in-house.
Hydrophilic nanostructured polymeric membranes for portable water production. Imparting hydrophilicity to old and newly formulated polymeric membranes as a way of minimising fouling and increasing membrane lifespan is generally accepted as the best method.
Prof Sabelo Mhlanga – Director
DST/Mintek Nanotechnology Innovation Centre – Water Research Node
Tel: +27(0)11 559 6187
Fax: +27(0)11 559 6425