(711a) Energy-Efficient Virus Removal with Cotton-Based DIY Water Filters

Fecal contamination of water and associated health burden is a global challenge. Acute diarrhea caused more than a million deaths worldwide in 2015¹. Although bacteria and protozoa cause diarrhea, human enteric viruses (EVs) are the major cause of water-related diarrhea, with just rotavirus causing 40% of the hospitalizations². Conventional filtration techniques, rapid and slow sand filtration, are not effective against viruses^3,4. Although membrane filtration techniques such as ultrafiltration, nanofiltration and reverse osmosis (UF, NF, and RO) were shown to be effective against viruses, continuous monitoring is necessary as any defects can hinder the performance drastically⁵. In addition, membrane filtration incurs high operational costs in terms of energy due to their small pore size, limiting their widespread use⁶. Due to the lack of a reliable filtration technology, disinfection and boiling are the available options at household and community scale for protection against viral contamination. Of which, boiling is again energy-intensive⁷, and practice of disinfection leads to formation of carcinogenic byproducts⁸. Therefore, there is a need for cost-effective, energy-efficient, and locally accessible virus filtration technologies.

In this work, we show that a simple filter made with unprocessed cotton balls functionalized with Moringa oleifera (MO) seed proteins can effectively capture viruses. Cationic proteins from MO seeds have been studied in relevance to indigenous water purification since 1979⁹. Using MS2 bacteriophage as a surrogate virus for EVs, we showed that the proposed filters can achieve ~7 log₁₀ removal of viruses, far exceeding the environmental protection agency requirements of 4 log₁₀ virus removal¹⁰. In addition, we compared the proposed MO-Cotton filters to commercially available UF and NF membranes to show that MO-Cotton filters can achieve effective virus removal with significantly low-energy requirement. Due to the cost-effective and chemical-free design we believe that MO-Cotton filters can be a potential solution for viral contamination of water worldwide.

References:

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(2) Organization, W. H. Global networks for surveillance of rotavirus gastroenteritis, 2001-2008. Weekly Epidemiological Record= Relevé épidémiologique hebdomadaire 2008, 83, 421-425.

(3) Yahya, M.; Cluff, C.; Gerba, C. Virus removal by slow sand filtration and nanofiltration. Water Science and Technology 1993, 27, 445-448.

(4) Shirasaki, N.; Matsushita, T.; Matsui, Y.; Yamashita, R. Evaluation of the suitability of a plant virus, pepper mild mottle virus, as a surrogate of human enteric viruses for assessment of the efficacy of coagulation–rapid sand filtration to remove those viruses. Water research 2018, 129, 460-469.

(5) Kumar, M.; Adham, S.; DeCarolis, J. Reverse osmosis integrity monitoring. Desalination 2007, 214, 138-149.

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(7) Gilman, R. H.; Skillicorn, P. Boiling of drinking-water: can a fuel-scarce community afford it? Bulletin of the World Health Organization 1985, 63, 157.

(8) Richardson, S. D.; Plewa, M. J.; Wagner, E. D.; Schoeny, R.; DeMarini, D. M. Occurrence, genotoxicity, and carcinogenicity of regulated and emerging disinfection by-products in drinking water: a review and roadmap for research. Mutation Research/Reviews in Mutation Research 2007, 636, 178-242.

(9) Jahn, S. A.; Dirar, H. Studies on natural water coagulants in the Sudan, with special reference to Moringa oleifera seeds. Water Sa 1979, 5, 90-106.

(10) USEPA: Long Term 2 Enhanced Surface Water Treatment Rule Toolbox Guidance Manual. USEPA, Office of Water Washington, 2010.