Removable smart sequestration coatings for hazardous metals
Materials are disclosed for the safe sequestration and removal of hazardous contaminants from a surface. The materials can be sprayed, rolled, painted, brushed or dip coated onto any surface and allowed to dry and/or cure at room temperature or drying/curing can be accelerated by the application of heat to form a coating that entraps the contaminant therein. The coating and the entrapped contaminant can then peeled from the surface and safely disposed of to minimize hazardous waste. The coating includes a colorimetric additive that is specific to the contaminant, the coating and the contaminant producing a visual indication of contamination.
1. A coating formulation including one or more colorimetric indicators for application to a surface, the one or more colorimetric indicators, after application to the surface, indicating the presence of metallic contaminant(s) on said surface by metal specific color changes wherein said coating formulation comprises 0.02-0.3 wt % of a silver dispersion, 83-90 weight % of a peelable waterborne acrylic polymer emulsion, 0.2-1 weight % of a surfactant and 10-17 weight % deionized (DI) water.
2. The coating formulation of claim 1 wherein the dried or cured film provides a darkening of the grayish silver dispersion color when exposed to metallic Hg in the coating.
3. The coating formulation of claim 1 wherein the film is cured for 24 to 48 hours.
4. The coating formulation of claim 1 , said film peeled from the surface by mechanical means with moderate force.
5. A coating formulation including one or more colorimetric indicators for application to a surface, the one or more colorimetric indicators, after application to the surface, indicating the presence of metallic contaminant(s) on said surface by metal specific color changes wherein said coating formulation comprises 0-4% by weight of a peelable vinyl acrylic copolymer water emulsion, 5-15 weight % of 1,5-diphenylthiocarbazone (Dithizone) in reagent alcohol, 0-1.5% by weight of Clinoptilolite and 79-90% by weight of peelable waterborne acrylic polymer emulsion.
6. The coating formulation of claim 5 wherein the film shows a color change from tan to localized regions of pink in the presence of elemental Hg or Hg (II) species sequestered in the coating, a color change from tan to localized regions of blue in the presence of Cu (II) species sequestered in the coating, and a color change from tan to localized regions of grey in the presence of Ni (II) species sequestered in the coating.
7. The coating formulation of claim 5 wherein the film is cured for 24 to 48 hours.
8. The coating formulation of claim 5 , said film peeled from the surface by mechanical means with moderate force.