Method for removal of beryllium contamination from an article
View Patent ↗A method of removal of beryllium contamination from an article is disclosed. The method typically involves dissolving polyisobutylene in a solvent such as hexane to form a tackifier solution, soaking the substrate in the tackifier to produce a preform, and then drying the preform to produce the cleaning medium. The cleaning media are typically used dry, without any liquid cleaning agent to rub the surface of the article and remove the beryllium contamination below a non-detect level. In some embodiments no detectible residue is transferred from the cleaning wipe to the article as a result of the cleaning process.
1. A method for removing beryllium contamination from a surface to a level of less than about 0.04 μg beryllium/100 cm 2 of surface area, the method comprising:
(a) dissolving a polyisobutylene to form a tackifier solution of approximately 0.5 wt % to approximately 10 wt % polyisobutylene;
(b) applying the tackifier solution to a substrate to produce a preform;
(c) drying the preform to form a dry cleaning wipe; and
(d) wiping the surface with the dry cleaning wipe to remove the beryllium contamination wherein the beryllium contamination is removed from the surface to a level of less than about 0.04 μg beryllium/100 cm 2 of surface area.
2. The method of claim 1 wherein step (d) comprises wiping the surface with the dry cleaning wipe without any liquid cleaning agent.
3. The method of claim 1 for removing beryllium contamination from a surface wherein step (a) comprises dissolving the polyisobutylene in a solvent to form a tackifier solution of approximately 0.5 wt % to approximately 1.5 wt % polyisobutylene.
4. The method of claim 1 for removing beryllium contamination from a surface wherein step (a) comprises dissolving the polyisobutylene in a solvent to form a tackifier solution of approximately 1.5 wt % to approximately 2 wt % polyisobutylene.
5. The method of claim 1 for removing beryllium contamination from a surface wherein step (a) comprises dissolving the polyisobutylene in a solvent to form a tackifier solution of approximately 2 wt % to approximately 3 wt % polyisobutylene.
6. The method of claim 1 for removing beryllium contamination from a surface wherein step (a) comprises dissolving the polyisobutylene in a solvent to form a tackifier solution of approximately 4 wt % to approximately 6 wt % polyisobutylene.
7. The method of claim 1 for removing beryllium contamination from a surface wherein step (a) comprises dissolving polyisobutylene having a viscosity average molecular weight (M VA ) over 30,000 in a solvent to form a tackifier solution of approximately 0.5 wt % to approximately 10 wt % polyisobutylene.
8. The method of claim 1 for removing beryllium contamination from a surface wherein step (a) comprises dissolving polyisobutylene having a viscosity average molecular weight (M VA ) between approximately 30,000 and 1,000,000 in a solvent to form a tackifier solution of approximately 0.5 wt % to approximately 10 wt % polyisobutylene.
9. The method of claim 1 for removing beryllium contamination from a surface wherein no significant residue from the dry cleaning wipe is detectable after step (d), as indicated by a carbon-to-iron X-ray Photoelectron Spectroscopy residual carbon-to-iron ratio of less than about 0.25 on stainless steel.
10. A method for removing beryllium contamination from a surface to a level of less than about 0.04 μg beryllium/100 cm 2 of surface area, the method comprising wiping the surface with a cleaning wipe consisting substantially of a porous substrate having a plurality of voids and polyisobutylene disposed within at least a portion of the plurality of voids.
11. The method of claim 10 for removing beryllium contamination from a surface wherein no significant residue from the cleaning wipe is detectable after removing the beryllium contamination, as indicated by a carbon-to-iron X-ray Photoelectron Spectroscopy residual carbon-to-iron ratio of less than about 0.25 on stainless steel.