Special Sand May Enable Better Water Purification

Creating water purification methods to aid the people of the Third World is a goal for many universities, but some experts have more interesting ideas than others. A group recently proposed using special, coated sand for purifying water.

The science team, based at the Rice University, says that nanotechnology is providing them with the edge they need to modify the sand according to needs. Sand is good at purifying water in its own right, but the investigators want to improve on this natural ability.

Their work may go on to benefit more than a billion people currently living in the world's poorest countries, who still lack access to clean drinking water. This is truly a research that can make a difference, the Rice group says.

Experts add that the thing which dictates the efficiency of purification when it comes to sand is surface roughness. The size of the particle, and the way its smoothness are also important factors.

Drawing from their extensive experience with nanotechnology, the Rice experts turned to graphite oxide for help. The material – which is used as a precursor for the production of graphene – can be fashioned into nanoscale layers.

By coating sand particles with graphite oxide, the investigators were able to boost the sand's purification efficiency several times over. Details of the study are published in the American Chemical Society journal Applied Materials and Interfaces.

The research effort was led by Pulickel Ajayan, a professor of mechanical engineering and materials science and of chemistry at the university. He and his team compared normal and coated sand in a number of filtration system types.

“By attaching different functional moieties onto graphite oxide, we could engineer some form of a 'super sand' to target specific contaminants species, like arsenic, trichloroethylene and others,” adds the primary author of the new work, Rice graduate student Wei Gao

Researchers from the Monash University, in Australia, and Marietta, Georgia-based Nanoholdings LLC were also a part of the work. Nanoholdings provided the bulk of the funds the team needed.