Yes / This article describes the synthesis and application of lanthanide-based luminophores for visualisation under short wavelength ultraviolet (UV) activation (typically 254 nm). Luminophores are chemical compounds which re-emit light of longer wavelength than typical fluorescence and phosphorescence, following photoexcitation, because of efficient energy transfer from the ligands to the lanthanide ion emission levels. The luminophores described in this article are all derived from europium and terbium metal complexes and cover the complete colour gamut. Selection of appropriate ligands allows for water solubility or water insolubility (if required pigment or disperse “dye” applications). Similar to dyeing or printing processes, the anionic complexes can be applied to polyamide fibres or to cellulosic fibres, whereas dispersions of the non-ionic complexes are suitable for polyester or cellulose acetate fibre application. The water-soluble derivatives are also suitable for ink-jet printing and the water-insoluble derivatives are suitable for lithographic or intaglio paper printing. The novel complexes are excited by radiation below 300 nm and thus cannot be activated by sunlight (the earth's atmosphere prevents light below about 300 nm reaching the surface). Accordingly, the photo-stability of the dyed materials and prints obtained is excellent. These materials could be used in security marking applications, for example bank-notes and passports, where they could replace the current fluorophores that are rendered visible under near UV light (typically 365 nm) illumination but exhibit relatively poor photo-stability. The development of an RGB (red, green and blue) colour palette for inkjet printing based on these innovative luminophores will significantly support the design of digitally printed security features. / The research was part funded by Inovink Ltd and theWorshipful Company of Clothworkers of the City of London.

The main objective of this study was to determine the applicability of advanced water treatment processes namely granular activated carbon (GAC) adsorption, ultraviolet (UV) light disinfectant and ozone in the management of deteriorating water quality in the Mid-Vaal River system for drinking purposes. Both the scarcity and the deteriorating quality of water in South Africa can be addressed by investigating advanced water treatment processes such as GAC adsorption, UV light disinfectant and ozone. Previously disregarded water resources have the potential to be purified and advanced treatments can improve water quality where conventional water treatments have failed. In addition, advanced treatment processes can be applied to treat used water. The two sampling sites selected for the study, Rand Water Barrage (RWB) and Midvaal Water Company (MWC), are both located in the Middle Vaal Water Management Area with RWB upstream of MWC. RWB uses GAC adsorption and UV light disinfection and MWC uses ozone as pre- and intermediate treatment process steps for water purification. The quality of the source water at both sampling sites was determined by analysing the physical and chemical characteristics as well as the algal and invertebrate compositions of the source water. The physical and chemical water quality variables measured included pH, conductivity, turbidity, dissolved organic carbon (DOC), total organic carbon (TOC), total photosynthetic pigments (TPP), microcystin and geosmin. The source water of both sites was characterised as hypertrophic on account of high chlorophyll concentrations. The water quality of the two sites was distinctly different and a downstream change was observed. The source water of RWB was characterised by high microcystin, geosmin, DOC, TOC and conductivity measurements and dominated by Bacillariophyceae (diatoms) and Cyanophyceae (blue-green bacteria). Problematic species that were present in the source water of RWB included Aulacoseira sp., other unidentified centric diatoms, Pandorina sp., Anabaena sp., Microcystis sp., Oscillatoria sp., Cryptomonas sp., Ceratium sp. and Trachelomonas sp. The source water of MWC was characterised by high pH, turbidity and TPP measurements and was dominated by Chlorophyceae (green algae) and Bacillariophyceae (diatom) species. Problematic algal species that were present in the source water of MWC included Cyclotella sp., Coelastrum sp., Pediastrum sp. and Scenedesmus sp. The source water of MWC was deemed to be of a better quality due to the lower Cyanophyceae concentrations and lower microcystin levels. The invertebrate composition of both sites was similar with Rotatoria as the dominant invertebrate group. The efficacy of GAC adsorption/UV light disinfection/ozonation on restoring the physical and chemical characteristics of the source water at both sampling sites as well as the algal and invertebrate compositions was determined by ascertaining the nature of the change in or the percentage removal of a water quality variable. The potable water of both sites complied with the standards of water intended for domestic use except for the conductivity at RWB that was slightly elevated. The phytoplankton was removed effectively from the source water of both sites but the removal of invertebrates was unsatisfactory. GAC adsorption and filtration proved to be more effective in the removal of TPP, turbidity, DOC, microcystin and geosmin than ozone. Ozone effected an increase in DOC. UV light disinfection had no or little effect on restoring the water quality variables investigated in this study. / M (Environmental Sciences), North-West University, Potchefstroom Campus, 2015

The main objective of this study was to determine the applicability of advanced water treatment processes namely granular activated carbon (GAC) adsorption, ultraviolet (UV) light disinfectant and ozone in the management of deteriorating water quality in the Mid-Vaal River system for drinking purposes. Both the scarcity and the deteriorating quality of water in South Africa can be addressed by investigating advanced water treatment processes such as GAC adsorption, UV light disinfectant and ozone. Previously disregarded water resources have the potential to be purified and advanced treatments can improve water quality where conventional water treatments have failed. In addition, advanced treatment processes can be applied to treat used water. The two sampling sites selected for the study, Rand Water Barrage (RWB) and Midvaal Water Company (MWC), are both located in the Middle Vaal Water Management Area with RWB upstream of MWC. RWB uses GAC adsorption and UV light disinfection and MWC uses ozone as pre- and intermediate treatment process steps for water purification. The quality of the source water at both sampling sites was determined by analysing the physical and chemical characteristics as well as the algal and invertebrate compositions of the source water. The physical and chemical water quality variables measured included pH, conductivity, turbidity, dissolved organic carbon (DOC), total organic carbon (TOC), total photosynthetic pigments (TPP), microcystin and geosmin. The source water of both sites was characterised as hypertrophic on account of high chlorophyll concentrations. The water quality of the two sites was distinctly different and a downstream change was observed. The source water of RWB was characterised by high microcystin, geosmin, DOC, TOC and conductivity measurements and dominated by Bacillariophyceae (diatoms) and Cyanophyceae (blue-green bacteria). Problematic species that were present in the source water of RWB included Aulacoseira sp., other unidentified centric diatoms, Pandorina sp., Anabaena sp., Microcystis sp., Oscillatoria sp., Cryptomonas sp., Ceratium sp. and Trachelomonas sp. The source water of MWC was characterised by high pH, turbidity and TPP measurements and was dominated by Chlorophyceae (green algae) and Bacillariophyceae (diatom) species. Problematic algal species that were present in the source water of MWC included Cyclotella sp., Coelastrum sp., Pediastrum sp. and Scenedesmus sp. The source water of MWC was deemed to be of a better quality due to the lower Cyanophyceae concentrations and lower microcystin levels. The invertebrate composition of both sites was similar with Rotatoria as the dominant invertebrate group. The efficacy of GAC adsorption/UV light disinfection/ozonation on restoring the physical and chemical characteristics of the source water at both sampling sites as well as the algal and invertebrate compositions was determined by ascertaining the nature of the change in or the percentage removal of a water quality variable. The potable water of both sites complied with the standards of water intended for domestic use except for the conductivity at RWB that was slightly elevated. The phytoplankton was removed effectively from the source water of both sites but the removal of invertebrates was unsatisfactory. GAC adsorption and filtration proved to be more effective in the removal of TPP, turbidity, DOC, microcystin and geosmin than ozone. Ozone effected an increase in DOC. UV light disinfection had no or little effect on restoring the water quality variables investigated in this study. / M (Environmental Sciences), North-West University, Potchefstroom Campus, 2015