New Material Absorbs
Mercury from Water

A material developed by scientists at the Battelle-managed Pacific Northwest National Laboratory (PNNL) has proven to be an effective and voracious tool for “absorbing” mercury from low-volume waste streams in a variety of real-life situations.

Thiol-SAMMS is a simple, inexpensive and easy-to-use technology that absorbs mercury in liquids and can be easily disposed of afterwards. “This technology will result in huge savings to users who are faced with costly disposal of mercury in the waste stream,” said Shas Mattigod, a staff scientist who manages the project.

Thiol-SAMMS was developed by PNNL scientist Glen Fryxell and his colleagues in 1996. “It’s like laying carpet,” Mattigod said. “Different carpet surfaces have different properties. You can apply a different type of monolayer to SAMMS depending on the contaminant you want to remove. This monolayer will seek out and adsorb specific contaminants.”

According to Mattigod, thiol-SAMMS surpassed developers’ expectations in tests of its mercury-absorbing capabilities. Recently, scientists used thiol-SAMMS powder on 10 liters of mercury-containing waste solution generated in one of PNNL’s labs, reducing mercury levels in the waste from 145.8 parts per million of mercury to 0.04 parts per million, safely below U.S. Environmental Protection Agency and Washington state limits of 0.15 parts per million.

“Because the solution was well below regulatory limits, we were able to save almost $2,000 in disposal costs,” Mattigod said. “Our tests have shown that mercury-laden thiol-SAMMS also passes EPA requirements for land disposal.”

Scientists also tested thiol-SAMMS for its ability to remove mercury from vacuum pump oil containing tritium. Mercury in the waste oil was reduced to less than 0.15 parts per million, again below EPA standards. “Using thiol-SAMMS on vacuum pump oil shows that thiol-SAMMS works not just in water solutions, but also in nonaqueous mediums,” Mattigod said. The monolayer can be custom designed to seek out a variety of contaminants. While thiol-SAMMS has been tailored to absorb mercury, silver, lead, and cadmium, other SAMMS technology is being developed and tested for removing toxic contaminants such as arsenic, chromium, and radionuclides.

Thiol-SAMMS in powder form is currently available for use on low-volume waste streams. A team of PNNL developers led by Rick Skaggs and Wayne Martin is also working on industrial applications for the technology. “In addition to the powder form, we’re developing an engineered version that will be adaptable for small to large scale systems,” Skaggs said. For additional information, contact Mr. Shas Mattigod at (509) 376-4311, shas.mattigod@pnl.gov or Mr. Walter Weimer at (509) 375-6922, walter.weimer@pnl.gov.