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August 12, 2013

Cactus "flesh" cleans up toxic water


Prickly pear cacti may be natural, cheaper answer to water cleanup

University of South Florida engineering professor Norma Alcantar and her team are using the "flesh" from Prickly Pear cacti, called mucilage, to clean up oil and other toxins from water. With support from the National Science Foundation (NSF), Alcantar has spent the last few years confirming something that her grandmother told her years ago--that cacti can purify water.

"This research is a good example of NSF's investment in sustainable chemistry which promotes the replacement of expensive and/or toxic chemicals with Earth-abundant, inexpensive and benign chemicals," says Debra Reinhart, program director in the Chemical, Bioengineering, Environmental and Transport Systems Division of the NSF's Engineering Directorate. The research is currently funded by the Gulf of Mexico Research Initiative (GOMRI) through the Consortium of Molecular Engineering of Dispersant Systems (C-MEDS).

The objectives of this research are to develop a water purification system based on an economically feasible method of water purification using cactus mucilage for low-income inhabitants of rural communities that are sensitive to existing economic, social and cultural patterns. The project transcends national boundaries as it includes collaborations among investigators at the University of South Florida, two leading Mexican public universities, and the National Institute of the Environment in Mexico.

The cactus project has been assessed for the rural communities of Temamatla in central Mexico, for Port-au-Prince, Haiti, after the 2010 earthquake, and for the Deepwater Horizon oil spill in the Gulf of Mexico in 2011. Temamatla is located 25 miles (40 kilometers) southeast of Mexico City and was critical for this study owing to its proximity to volcanic soils where the concentration of heavy metals such as cobalt, mercury, nickel, copper, zinc, iron, manganese, chromium, iodine, arsenic, molybdenum and lead in local water supplies may be higher than recommended values. In Haiti, the outcomes of the project were to determine the ground water quality after the earthquake and evaluate the feasibility of implementing a low cost technology for disaster relief based on cactus mucilage. The cactus mucilage is also able to disperse crude oil efficiently at much lower concentrations than synthetic dispersants.

The broader implications of this project include the multidisciplinary participation of American and Mexican researchers in issues that are relevant to both countries owing to their proximity and preexisting ties. Such collaboration will promote mutual opportunities and infrastructure for research, education, training, networking and future partnerships. Most importantly, the proposed technology will improve current water-related issues and problems in areas of extreme need.

Miles O'Brien, Science Nation Correspondent
Marsha Walton, Science Nation Producer


Any opinions, findings, conclusions or recommendations presented in this material are only those of the presenter grantee/researcher, author, or agency employee; and do not necessarily reflect the views of the National Science Foundation.