Influence of Process Parameters on Chlorinated Biocide Decontamination by li-CO₂ on Artificially Contaminated Model Materials

ABSTRACT

Previously, heavy use of biocides for the treatment of objects made of organic materials in museum collections (e.g. ethnographic, historical collections) was very common. Now suitable decontamination methods/technologies are being sought. A decontamination treatment by li-CO₂ was optimized that considered the specific requirements of museum objects. The treatment was tested on model materials artificially contaminated with biocide solutions containing dichlorodiphenyltrichloroethane (DDT), pentachlorophenol (PCP), lindane, and permethrin or cypermethrin. High decontamination was achieved for DDT, lindane, PCP, and permethrin on artificially biocide loaded wool and wood model materials. Optimal process parameter settings for li-CO₂ decontamination include a single 30 min cycle for woolen materials and three sequential 30 min cycles each for wood. These methods allow a reduction of at least 90% of all biocides for wool and between 70% and 85% for wood. Decontamination of the latter was more effective for less polar biocides as DDT and permethrin. Despite a significant improvement in decontamination for wood using co-solvents such as acetone, ethanol, and methyl tertiary-butyl ether (MTBE), their use is not recommended due to the increased risk of damage to the objects, in particular if a surface coating is present.

KEYWORDS:

• Biocide contamination
• museum collections
• liquid CO₂
• decontamination
• model materials

Acknowledgements

The authors are grateful to the Federal Office for the Environment (FOEN) for financially supporting the project and to the staff of the Department of Innovation of the FOEN for their support and scientific interest.

Disclosure statement

No potential conflict of interest was reported by the authors.

List of suppliers

Sigma-Aldrich: Lindane (product number 233390), PCP (product number P260-4), Acetone (product number 34850), Ethanol (product number 02860), and MTBE (product number 443808);

Santa Cruz Biotechnology: DDT (product number SC238975);

Agriphar S.A.: Permethrin (product number unknown).

Health and safety issues

DDT, PCP, lindane, and cypermethrin are toxic substances. DDT and PCP might also cause cancer. DDT, lindane, and PCP are Persistent Organic Pollutants. Acetone, ethanol, and MTBE are highly flammable liquids and vapors. Health and safety datasheets can be found on-line from distributor web sites.

GHS (Global Harmonized System) hazard statements:

• - PCP: H301, H311, H315, H319, H330, H335, H351, H410, P260, P273, P280, P284, P301 + P310, P305 + P351 + P338

• - Lindane: H301, H312 + H332, H362, H373, H410, P201, P260, P263, P273, P301 + P310 + P330, P302 + P352 + P312

• - DDT: H301 + H311, H351, H372, H410, P273, P280, P301 + P310, P314, P501

• - Permethrin: H302 + H332, H317, H410, P273, P280, P501

• - Cypermethrin: H301, H315, H317, H332, H335, H373, H410, P260, P280, P301 + P330 + P331 + P310

• - Acetone: H225, H319, H336, P210, P280, P304 + P340 + P312, P305 + P351 + P338, P337 + P313, P403 + P235

• - Ethanol: H225, H319, P210, P280, P305 + P351 + P338, P337 + P313, P403 + P235

• - MTBE: H225, H315, P210

ORCID

Tiziana Lombardo http://orcid.org/0000-0002-7941-0576

Christina Hinterleitner http://orcid.org/0000-0003-2056-7488

Additional information

Funding

This work was supported by Bundesamt für Umwelt [Grant Number UTF 444.40.12 / IDM 2006.2423.395].