科学家弄清了一种常见的可以食用的仙人掌如何净水的原因，这为它在发展中国家的使用铺平了道路。该研究成果发表在《环境科学与技术》（Environmental Science & Technology）上。
胭脂仙人掌原产于美国，而且在非洲大陆、墨西哥和其他发展中国家广泛种植。这组科学家说，它如今可以成为发展中国家的农村地区的一种可持续和可负担得起的净水方法。
科学家已经知道胭脂仙人掌能够净水，但是他们对于这种机制的理解仍然不够充分。
他们在被污染的水中测试了两种粘液——仙人掌分泌的胶状物质。仙人掌通过让沉淀物和细菌聚集成小的絮状物从而在15分钟内去除了98%的细菌，这些絮状物可以很容易地过滤掉。
这组科学家说，这些发现为使用多少仙人掌用于净水的指南铺平了道路。现在已经有了用辣木种子净水的指南，这是另一种天然净水剂。
“我们设想社区可以在使用仙人掌填饱肚子的同时用它清洁水。”该研究的第一作者、美国佛罗里达大学的Norma Alcantar说。
她说，当她在一个墨西哥农村社区测试这些仙人掌的时候，“人们全都接受使用仙人掌的做法”。
但是墨西哥水技术研究所（IMTA）水净化项目的负责人Alejandra Martín认为，最大的挑战在于教育人们净化水的重要性。“我们看来这是必要的，但是他们却不这样认为”，她说，“一些当地社区并不净化水，”IMTA的社会参与项目负责人Daniel Murillo说，“胃肠感染被认为是清洁身体的一种方式，而不被认为是一种疾病”。
Alcantar的研究组如今正在与墨西哥的非营利组织和大学一起组织教育项目。她预计将在6月启动一个类似的项目，从而帮助最近海地地震引起的水问题。
瑞典Uppsala 大学的材料物理学家Adrian Rennie的研究包括利用辣木种子净水，他说很乐意看到关于天然聚合物净水的更详细的研究，因为不同的环境适合不同的生物聚合物。（生物谷Bioon.com）
Nature Nanotechnology ：净水芯片可分离出99的污染物
生物谷推荐原文出处：
Environ. Sci. Technol. DOI: 10.1021/es9030744
Removal of Sediment and Bacteria from Water Using Green Chemistry
Audrey L. Buttice?, Joyce M. Stroot?, Daniel V. Lim?, Peter G. Stroot§ and Norma A. Alcantar*?
Department of Chemical and Biomedical Engineering, Department of Cell Biology, Microbiology, and Molecular Biology, and Department of Civil and Environmental Engineering, University of South Florida, Tampa, Florida 33620
Although nearly all newly derived water purification methods have improved the water quality in developing countries, few have been accepted and maintained for long-term use. Field studies indicate that the most beneficial methods use indigenous resources, as they are both accessible and accepted by communities they help. In an effort to implement a material that will meet community needs, two fractions of mucilage gum were extracted from the Opuntia ficus-indica cactus and tested as flocculation agents against sediment and bacterial contamination. As diatomic ions are known to affect both mucilage and promote cell aggregation, CaCl2 was studied in conjunction and compared with mucilage as a bacteria removal method. To evaluate performance, ion-rich waters that mimic natural water bodies were prepared. Column tests containing suspensions of the sediment kaolin exhibited particle flocculation and settling rates up to 13.2 cm/min with mucilage versus control settling rates of 0.5 cm/min. Bacillus cereus tests displayed flocculation and improved settling times with mucilage concentrations lower than 5 ppm and removal rates between 97 and 98% were observed for high bacteria concentration tests (>108 cells/ml). This natural material not only displays water purification abilities, but it is also affordable, renewable and readily available.
