M.Sc. / Improper disposal of industrial effluents that contain heavy metals such as mercury causes a threat to the environment due to the toxic effects of such matal even at low concentrations. It is also known that sewage waste in water contains bacteria that pose a health hazard to human beings, animals and micro-organisms. One major concern is the transmission of diseases through drinking this water; which destabilizes the water supply. Water for human consumption therefore needs to be of high quality. In this study copper-containing multiwalled carbon nanotubes (Cu/MWCNTs) were investigated for their ability to remove and kill mercury (Hg2+) and Escherichia coli (E. coli), a major species found in the coliform bacteria. These Cu/MWCNTs were synthesized “in situ” by using an electric arc-discharge apparatus and separately via one of two multi-step wet chemical techniques namely; an electroless plating and impregnation method respectively. MWCNTs used for the wet techniques were synthesized by a nebulized spray pyrolysis (NSP) process using ferrocene/toluene under argon flow. These MWCNTs were purified and functionalized to introduce functional groups that made provision for the nucleation of the copper metal on the surface of MWCNTs. Infrared spectroscopy confirmed the successful introduction of COOH and O-H groups on the surface of MWCNTs. Raman spectroscopy confirmed a relative increase in the intensity the ratio of the D-band after functionalization. Deposition of the copper nanoparticles by electroless plating method in different volumes of 100 ml, 80 ml and 60 ml produced copper nanoparticles of varying sizes and distribution on the surface of MWCNTs. SEM images revealed densely and homogeneously distributed small sized copper nanoparticles that followed the trend; 100 ml> 80 ml > 60 ml. The volume proved to be a critical factor of the electroless plating bath with an increase or decrease of the volume affecting the concentration of the Cu2+ ions and HCHO, which also affected the pH of the plating solution.

In the rural areas of Madagascar only 29% of the population has access to clean water and 10% has access to improved sanitation. It has been estimated that environmental risk factors, such as inadequate access to clean drinking water and proper sanitation, are responsible for 94% of the diarrheal disease burden. This study was focused on testing a point-of-use technology called the Tulip filter, which is a siphon ceramic candle filter impregnated with silver. The purpose is to assess its feasibility for implementation in rural regions of Madagascar through a laboratory study performed at the University of South Florida. The study tested the Tulip filters for turbidity, total coliform, and E. coli removal for various types of water. Each filter processed synthetic water classified as control (tap water, <1 >NTU), low turbidity (5-7 NTU), medium turbidity (25-35 NTU), or high turbidity (60-80 NTU). Approximately once every 100 L the filters processed pond water to test coliform removal. Furthermore, the pthesis size distribution was measured to analyze the effectiveness of filter to remove various pthesis sizes. Two of the seven Tulip filters tested had some quality control issues with the glue connecting the ceramic candle to the plastic cap and failed at 350 L. Of the functioning filters, the turbidity removal ranged from 93% to 98% with none of the 779 samples taken from 4 filters above the WHO recommended 5 NTU for drinking water. The log removal of total coliforms was about 3.90 to 4.16 and achieved an average of 1 CFU/100mL of E. coli in the filtered water. WHO guidelines consider water with 1-10 CFU/100 mL a "low risk" and all but one of the working filters had E. coli and total coliform concentrations within, or below, this range for all samples (n=20 for each filter). The filters also showed an average of 96% removal of pthesiss of all size ranging from 0.5 to 10 µm. This study finds that the Tulip filter is an appropriate of point-of-use technology that enables rural areas access to "low risk" water, at a low cost and with minimal maintenance. This study also reinforces the importance of adding silver or another biocide to ceramic filters because pthesiss of sizes up to 10 µm are able to pass through the filter. This is particularly a problem because pathogens can range from 0.01 µm to 100 µm.