Technology.am (July 23, 2009) — Sandia National Laboratories have created a far more effective decontaminant with a shelf life superior to products currently on the market. By substituting a single atom in a molecule widely used to purify water.
Sandia has applied for a patent on the material, which removes bacterial, viral and other organic and inorganic contaminants from river water destined for human consumption, and from wastewater treatment plants prior to returning water to the environment.
The water-treatment reagent, known as a coagulant, is made by substituting an atom of gallium in the center of an aluminum oxide cluster — itself a commonly used coagulant in water purification.
The substitution isn’t performed atom by atom using nanoscopic tweezers but rather uses a simple chemical process of dissolving aluminum salts in water, gallium salts into a sodium hydroxide solution and then slowly adding the sodium hydroxide solution to the aluminum solution while heating.
The substitution of a single gallium atom in that compound makes a big difference. It greatly improves the stability and effectiveness of the reagent.
The Sandia coagulant attracts and binds contaminants so well because it maintains its electrostatic charge more reliably than conventional coagulants made without gallium, itself a harmless addition. The new material also resists converting to larger, less-reactive aggregates before it is used.
The bar graph in the given picture shows the efficacy of removing wild-type bacteriophage from Rio Grande water using the all-aluminum coagulant (yellow), the gallium-aluminum coagulant (pink) and a germanium-aluminum coagulant (green). While the gallium-aluminum coagulant is most effective, the germanium-aluminum coagulant is less effective than the all-aluminum coagulant.
The gallium makes the active ingredient for binding contaminants more stable and effective, while the germanium, introduced as another variable, was found to make the active ingredient less stable and less effective.