Grantee Research Project Results
2004 Progress Report: Use of Ozonation in Combination with Nanocrystalline Ceramic Membranes for Controlling Disinfection By-products
EPA Grant Number: R830908Title: Use of Ozonation in Combination with Nanocrystalline Ceramic Membranes for Controlling Disinfection By-products
Investigators: Masten, Susan J. , Baumann, Melissa J.
Institution: Michigan State University
EPA Project Officer: Hahn, Intaek
Project Period: May 15, 2003 through May 14, 2006
Project Period Covered by this Report: May 15, 2004 through May 14, 2005
Project Amount: $353,959
RFA: Environmental Futures Research in Nanoscale Science Engineering and Technology (2002) RFA Text | Recipients Lists
Research Category: Nanotechnology , Safer Chemicals
Objective:
The goal of this research project is to determine the feasibility of using a combined ozonation and membrane filtration system to control disinfection by product s (DBP s) precursors in the drinking water treatment process. Conventional ceramic membranes and ceramic membranes coated with a nanocrystalline catalyst that decomposes ozone will be used in this study. The specific objectives are to: (1) develop methods for the preparation of a nanocrystalline ceramic membrane s that catalyze the decomposition of ozone and foulants and to characterize these membranes; (2) determine the effect of ozonation on membrane fouling in filtration systems using both commercial and catalytic membranes; (3) determine, for the source waters studied, the effect of ozonation on the properties of natural organic matter and relate this information to the overall performance of the system; and (4) investigate the effect of control parameters on the fouling rate and product water quality using selected conventional and catalytic membranes. Catalytic membranes were produced by coating c ommercially available Alumina-zirconia-titania (AZT) ceramic membranes with Fe2O3 nanoparticles having an average diameter of 4-6 nm and then sintering the membranes.
Progress Summary:
Commercial titania membranes, with a molecular weight cut-off of 1, 5, and 15 kD were used in an ozonation/membrane system that was fed with water (pre-filtered through a 0.45 micron glass fiber filter) from Lake Lansing. The application of ozone gas prior to filtration resulted in significant decreases in membrane fouling. The effects of ozonation could not be explained by physical scouring of the filter cake. Increasing the ozone concentration beyond a threshold value had no beneficial effect on permeate flux recovery. The studies show that decreases in the pH resulted in a concomitant increase in the dissolved ozone concentration in the feed water and an improvement in permeate flux recovery. Ozonation resulted in the formation of partially oxidized compounds from natural organic matter that were less reactive with chlorine, decreasing the concentration of total trihalomethanes and haloacetic acids. We found that the ozone-membrane filtration system required a minimum ozone dose of 1.5 g/m3 and a 5 kD membrane to reduce DBP in the water sample to acceptable levels under the Safe Drinking Water Act.
A novel procedure for coating alumina-zirconia-titania (AZT) nano-crystalline ceramic membranes purchased from a commercial supplier has been developed. The layer-by-layer technique used to coat the membranes is based on a protocol described by McKenzie et al. [36]. The membrane was immersed in the colloidal suspension for one minute and then rinsed with DDI water. Then, the membrane was immersed in an aqueous phytic acid (40 mM) for one minute and rinsed with the DDI water. This sequence was repeated to give the desired number of layers (20, 30, 35, 40, or 45) of iron oxide nanoparticles. After coating, the membrane was either sintered at 500 °C for 60 minutes or sintered at 900 °C for 30 minutes. These two temperatures were chosen to produce membranes on which the iron oxide particles were attached but not fused to each other (500 ºC) or completely sintered to each other and to the membrane surface (900 ºC). The effect of sintering at several other temperatures was also considered. We found that membranes prepared with 40 coatings and sintered at 900 ºC resulted in a membrane that has extremely effective catalytic properties. With the iron oxide coated membrane, t he concentration of dissolved organic carbon was reduced by more than 85 percent, and the concentrations of simulated distribution system total trihalomethanes and simulated distribution system haloacetic acids decreased by up to 90 percent and 85 percent, respectively, compared to concentrations found with untreated water. When the coated membrane was used, the concentrations of ozonation DBPs (aldehydes, ketones, and ketoacids) in the permeate were reduced by more than 50 percent compared to that obtained with the uncoated membranes. Under the conditions used in our experiments, no fouling problems have been observed with the catalytic membrane. It appears that the coated membrane catalyzes the degradation of the foulants by ozone. Fouling is not observed even at very low dissolved ozone concentration (< 0.1 mg/L).
The effects of sintering and coating layer thickness on the microstructure of the ceramic membranes were characterized using atomic force microscopy (AFM) and scanning electron microscopy (SEM). There was evidence of changes in the surface morphology of the membrane with Fe2O3 coating. SEM micrographs show coarsening of the membrane surface with the average grain size increasing from approximately 21 nm for the uncoated membranes to approximately 66 nm for the coated membranes. The coated membrane surface gives a much more open surface area with pore size of 200 nm ascompared to 400 nm size for the uncoated membrane. AFM images show a corresponding decrease in the roughness of the membrane surface with an increase in the number of coatings. The transmission electron micrographs show a thickness of approximately 50 nm compared to the predicted coating thickness of approximately 200 nm for the membranes receiving 40 coating layers. Probable reasons include non-uniform surface coverage and variations in processing and/or agglomeration of the Fe2O3 nanoparticles on the surface. Work is ongoing to characterize the membranes developed using other analytical techniques, such as X-ray photoemission spectrometry and X-ray diffraction.
Future Activities:
A major goal of the proposal is to develop catalytic membranes. Further work will be conducted to characterize the coated membrane to increase understanding of how the fabrication procedure affects the structure and catalytic properties of the membrane coating.
The Lake Lansing water contains low bromide concentration. Because bromide not only reacts with ozone and forms bromate, but also affects the formation of other DBPs, it is important to investigate the applicability of this system on waters containing high bromide concentrations. We will perform these studies using Lake Lansing water spiked with bromide.
Journal Articles on this Report : 5 Displayed | Download in RIS Format
Other project views: | All 10 publications | 5 publications in selected types | All 5 journal articles |
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Chen KC, Davies SH, Masten SJ. Mass transfer of ozone in a hybrid ozonation-membrane system. Journal of Advanced Oxidation Technologies 2007;10(2):287-296. |
R830908 (2004) |
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Karnik BS, Davies SH, Chen KC, Jaglowski DR, et al. Effects of ozonation on the permeate flux of nanocrystalline ceramic membranes. Water Research 2005;39(4) :728-734. |
R830908 (2003) R830908 (2004) |
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Karnik BS, Davies SH, Baumann MJ, Masten SJ. Fabrication of catalytic membranes for the treatment of drinking water using combined ozonation and ultrafiltration. Environmental Science and Technology 2005;39(19):7656-7661. |
R830908 (2004) |
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Karnik BS, Davies SH, Baumann MJ, Masten SJ. The effects of combined ozonation and filtration on disinfection by-product formation. Water Research 2005; 39(13):2839-2850. |
R830908 (2004) |
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Karnik BS, Baumann MJ, Masten SJ, Davies SH. AFM and SEM characterization of iron oxide coated ceramic membranes. Journal of Materials Science 2006;41(20):6861-6870. |
R830908 (2004) |
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Supplemental Keywords:
groundwater, chemicals, oxidants, pathogens, viruses, bacteria, , disinfection, oxidation, ecosystem protection/environmental exposure and risk, international cooperation, sustainable industry/business, water, analytical chemistry, chemical engineering, chemistry, materials science, drinking water, engineering, physics, environmental chemistry, environmental engineering, environmental monitoring, monitoring/modeling, new/innovative technologies, physics, DBP exposure, analytical methods, disinfection by-products, DBPs, disinfection of waters, drinking water contaminants, drinking water treatment, environmental measurement, health effects, heavy metals, membrane filtration, nanocrystalline ceramic membranes, nanocrystals, nanoengineering, nanotechnology,, RFA, Scientific Discipline, INTERNATIONAL COOPERATION, Water, Ecosystem Protection/Environmental Exposure & Risk, Sustainable Industry/Business, Chemical Engineering, Environmental Chemistry, Monitoring/Modeling, Environmental Monitoring, New/Innovative technologies, Drinking Water, Engineering, Chemistry, & Physics, Environmental Engineering, health effects, disinfection by-products, nanotechnology, disinfection byproducts (DPBs), disinfection of waters, membrane filtration, analytical chemistry, analytical methods, nanocrystalline ceramic membranes, water quality, nanocrystals, DBP exposure, drinking water contaminants, drinking water treatment, nanoengineeringProgress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.