Elvis Fosso-Kankeu

Adsorption of Congo Red by surfactant-impregnated bentonite clay

AbstractDue to an ever-changing climate and invasive foreign plant species increase, South Africa struggles with limited water resources. Water is important for the sustenance of all living organisms and it has to be protected. The development of different water treatment techniques becomes more popular to achieve efficient and cost-effective ways of removing contaminants from water. In this study, the property of bentonite clay was altered through impregnation with surfactants such as benzyltrimethylammonium chloride (BTMA), hexadecyltrimethylammonium bromide (HDTM) and tris(hydroxymethyl)aminomethane (THMA) and then used for the removal of the anionic dye, Congo Red (CR), from solutions. The characterization of the different clay samples was done with the use of X-ray diffractometer, X-ray fluorometer and FTIR spectroscopy. To determine the bentonite adsorption affinity the pseudo-first- and second-order kinetic models were used as well as the Langmuir- and Freundlich isotherm models. Other influencing ...

Metal Speciation in the Rivers Around Potchefstroom Based on Seasonality

  About 44 surface water samples were collected in the wet and dry seasons around mining areas near the city of Potchefstroom in South Africa, and physicochemical parameters were analyzed to assess the speciation of pollutants and impact on dispersion potential. It was found that concentrations of the trace elements measured decreased significantly during the dry season. High concentrations of trace elements during the wet season were correlated to high effluents from anthropogenic sources which were flowing into the surface water. Aqueous metal speciation in both seasons was conducted using the PHREEQC geochemical modelling code. The seasonal variation of species observed was due to changes in the physicochemical quality of water between the two seasons. Collected data indicated that high percentages of Ca and Mg were present as free hydrate species, whereas the Fe, Cd, As, and U were mostly present as carbonate or hydroxide species.

9 – Photocatalytic degradation and adsorption techniques involving nanomaterials for biotoxins removal from drinking water

The world is facing a problem on shortage of freshwater and the degradation of the quality of available water by anthropogenous activities. The nature of the pollutants may make the situation worse as more efforts will require ensuring that safe water is provided to the population. One of the challenges currently faced by the water authorities is the identification and removal of the so-called emerging contaminants, which include biotoxins. Biotoxins, such as cyanotoxins and mycotoxins occurring in drinking water are increasingly recognized as potential risks to human health. However, the conventional water treatment processes in developing countries are often not equipped with adequate techniques for specific removal of these toxins from water. There has been significant development of nanotechnology and expansion of the application in various sectors of activity including water treatment. The application of nanotechnology currently allows the removal of recalcitrant pollutants through adsorption or photocatalytic degradation. Metal oxide nanomaterials, as well as carbon nanoparticles exhibit suitable properties for photocalytic degradation and adsorption processes respectively. They have been extensively used in the recent years for remediation of water pollution. This chapter covers the limitations of conventional water treatment techniques in the removal of biotoxins and reviews the potential of nanomaterials-based treatment in the removal of such toxins.