Two fairly common materials could be the answer to cost effective water purification. Recent studies have found that graphite-coated sand, called ‘super sand’, is a cheap way to purify water.
Sand has been used for water purification since ancient times, but coating the sand in graphite allows the use of coarse-grained sand, which would normally not filter out many pollutants. Fine-grained sand works slightly better, but the process is very slow. The combination of graphite and sand allows most pollutants to be filtered out in a timely fashion.
Approximately one out of every eight people lack access to safe drinking water, 884 million people worldwide. Many deadly diseases are directly related to unsafe drinking water and sanitation issues.
Dr. Mainak Majumder from Monash University in Melbourne Australia explains the economic advantages of this approach. "This material demonstrates comparable performance to some commercially available activated carbon materials, but given that this can be synthesized using room temperature processes and also from cheap graphite sources, it is likely to be cost-efficient." In English, because the materials are available and the manufacturing process is fairly simple, the end product is not very expensive to produce. Majumder also points out that, in Australia, many mining companies produce graphite rich waste, which can then be used for water purification purposes.
SOURCE: BBC, WATER.ORG