Continuous flow experiments (450 mL min) were performed in household filter in order to investigate the removal and/or inactivation of T4 bacteriophage, using granular activated carbon (GAC) modified with silver and/or copper oxide nanoparticles at different concentrations. GAC and modified GAC were characterized by X-ray diffractometry, specific surface area, pore size and volume, pore average diameter, scanning electron microscopy, transmission electron microscopy, zeta potential and atomic absorption spectroscopy. The antiviral activity of the produced porous media was evaluated by passing suspensions of T4 bacteriophage (∼10 UFP/mL) through filters. The filtered water was analyzed for the presence of the bacteriophage and the release of silver and copper oxide. The porous media containing silver and copper oxide nanoparticles showed high inactivation capacity, even reaching reductions higher than 3 log. GAC6 (GAC/Ag0.5%Cu1.0%) was effective in the bacteriophage inactivation, reaching 5.53 log reduction. The levels of silver and copper released in filtered water were below the recommended limits (100 ppb for silver and 1000 ppb for copper) in drinking water. From this study, it is possible to conclude that activated carbon modified with silver and copper oxide nanoparticles can be used as a filter for virus removal in the treatment of drinking water.
This paper presents filtration results for drinking water treatment obtained with a commercial cellulose acetate membrane of 0.45 m pore diameter, with and without TiO 2 coating. The deposition of titanium dioxide thin films onto membrane surface was made by pulsed-frequency d.c. reactive magnetron sputtering at room temperature from a high purity Ti target in Ar/O 2 /N 2 atmosphere, at different conditions for cathode current and for deposition time. The proposed membranes were used in a filtration system driven by gravitation without the requirement of energy supply. The obtained results showed that the proposed system is able to remove color and turbidity from raw water. Besides, the modified membrane presented better results than the neat one regarding to membrane fouling and chlorine removal.
This study aimed to produce modified granular activated carbon (GAC) by low concentrations of silver (Ag) and/or copper (Cu) nanoparticles with antibacterial capacity for application in water purification. Modified porous materials were produced from the vacuum impregnation method, at the concentrations (mass of metal/mass of activated carbon) of Ag 8 x 10−4 g/g (Ag 0.08 %), Cu 1 x 10−2 g/g (Cu 1 %), and Ag 8 x 10−4 g/g + Cu 1 x 10−2 g/g (Ag 0.08 % Cu 1 %). The reduction of the metal salts in NPs of Ag and Cu in their metallic forms or oxides was carried out by the thermal decomposition method. The characterization of the produced porous material was performed by x‐ray diffraction, programmed temperature reduction, scanning electron microscopy, x‐ray dispersive energy spectroscopy, electron transmission microscopy, and specific surface area measurements: Brunauer, Emmet, and Teller; micropore area (t method); pore size distribution (DA method); and volume and diameter of micropores (HK method) and mesopores (BJH method). In the structure of the material produced, Ag and Cu metal compounds and AgO and CuO oxides were identified, with average crystallite sizes of < 60 nm. The efficiency of the inactivation of Escherichia coli was more significant in the GAC modified with the combination of NPs (GAC/NP‐AgCu) (6.4 log
10 units), evidencing the synergistic effect of the metals when compared to GAC/NP‐Ag (0.56 log10 units) and GAC/NP‐Cu (1.31 log10 units) modified porous material. Thus, these antibacterial materials can be used for application in water purification, improving the bacteriological quality of water intended for human consumption, noting that the low concentration of metals used can provide exceptional process efficiency.
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