Cleaning and reuse of a plastic container that previously held 10M HCl

Cleaning and reuse of a plastic container that previously held 10M HCl: I have a large (2.5L) commercial stock plastic container that is empty. It used to contain 10M HCl and I would like to wash it out and reuse the container. What is the best way to do this? Should I add water to the container and neutralise any remaining acid with sodium carbonate? Or should I add dilute sodium carbonate solution directly to the container? I don't want to cause a massive exothermic reaction and break the container.

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Publication Date: 12 March 2019
Asked By: Anonymous
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Cleaning and reuse of a plastic container that previously held 10M HCl

Cleaning the container:

If your container is empty, then there would only be a small amount of residual 10M HCl, which would be unlikely to cause any extreme exothermic reaction. We recommend the following steps:

  • In an operating fume cupboard and wearing appropriate PPE, add water to thoroughly rinse out the bottle and collect the rinse waters in a beaker. Repeat the rinse process 3 times.
  • Neutralise the rinse water to a pH between 6-8 with sodium carbonate powder or solution. Use universal indicator or pH strips to give an indication of the pH of the waste solution before washing to waste
  • Assess the suitability of the bottle for reuse, see points below. If the container is determined to be suitable then we recommend reuse only with chemicals that are compatible.
  • Take the bottle out of the fume cupboard and wash with warm water and a mild detergent and rinse well several times with tap water followed by deionised or distilled water. It is also important to remove any detergent residues prior to reuse.
  • Care must be taken not to use anything abrasive that might scratch the plastic. Note that strong alkaline detergents can crack and craze polycarbonate surfaces.1
  • Allow to thoroughly dry before reuse.

Caution: concentrated acids being stored in plastic bottles:

We have concerns regarding the integrity of the container as it may have deteriorated due to an extended length of time storing a corrosive liquid in addition to possible degradation from light and storage temperature.

Regular checks on the integrity of existing plastic storage bottles for all concentrated acids should be conducted to reduce the likelihood of the bottle breaking and causing a spill of concentrated acid.  

  • Check that the container has not degraded
  • Check that the cap and any cap liner are in good condition
  • Check that the cap is fitted securely to prevent leaks and evaporation.

If the integrity of the container has been compromised, then we recommend that in conjunction with a risk assessment and using safe procedures, it is decanted into an appropriately labelled glass screw capped bottle.

We recommend schools

  • purchase and store chemicals in minimum quantities
  • assess all chemicals periodically (Stocktake is a suitable time to do this).
  • provide secondary containment for concentrated acids, such that it could provide enough volume to contain the bottle and its entire contents if the bottle broke.

Effect of chemicals on plastics:

Different plastics react differently to different types of chemicals. Exposure of plastics to chemicals can result in physical changes to colour, flexibility, surface appearance and strength. Furthermore the chemical resistance of some plastics can be influenced by chemical concentration, temperature and duration and frequency of exposure. A plastic container should not be reused if any of the following are evident:2

  • Hazing or stress cracks due to chemical and physical stresses
  • Yellowing due to age and/or UV light exposure
  • Weakness due to extreme temperature exposure

Consult a chemical compatibility chart for different types of plastic and the chemical SDS for specific storage requirements.

Assessing the suitability of a container for reuse:

An initial risk assessment should be conducted to determine the physical condition and suitability of a plastic chemical storage container for reuse:

  • The condition of the container and its lid
    • must be checked for any signs of deterioration as plastics can be affected by age and chemical attack.
    • must be thoroughly cleaned of any chemical residue prior to reuse to ensure no incompatible reaction between any new chemicals being stored. If the rinsing water from cleaning the container is hazardous, it must be collected and either treated to safely put down the sink or be disposed of as hazardous waste.
  • The type of container and its lid
    • must be chemically resistant to any new chemical.
    • must suit the chemical properties of any new chemical, such as if it light-sensitive, hygroscopic and if a vented lid is required
    • should have a suitable sized opening. Wide mouth containers are suitable for storing solids and viscous liquids while narrow mouth containers are suitable for storing liquids.
  • Original labels should be retained until just prior to reuse to ensure that there are no incompatibilities with the original contents of the container.  The label must then be removed and the container should be:
    • disposed if not suitable for reuse
    • clearly labelled with the new contents if it is to be reused
  • Old empty containers which contained substances which are very water-soluble and of low hazard are suitable for use as waste containers. Never use the container of an acutely toxic or highly reactive chemical as a waste container. These should be stored for collection by a waste disposal contractor.

See also a previous answer from Science ASSIST: chemical storage bottles

References and further reading.

1 Bel-Art – SP Scienceware. 2012. Cleaning and Sterilization Guide to Plastic Labware, Bel-art website, https://www.belart.com/corporate/Resources/Cleaning%20and%20Sterilizatio...

2Thermo Scientific. 2009. Thermo Scientific Nalgene Plastics Technical Guide, University of Alaska Anchorage website, https://www.uaa.alaska.edu/about/administrative-services/departments/fac...

 

‘Characteristic properties of commonly used laboratory plastic materials’, Lab training website, http://lab-training.com/2016/12/08/characteristic-properties-commonly-us... (8 December 2016)

‘Cleaning Practices for Laboratory Plastic ware’, Lab training website, http://lab-training.com/2016/12/09/cleaning-practices-laboratory-plastic... (9 December 2016)

Environmental Health and Safety, University of Washington. 2017. Empty Chemical Containers Environmental Health and Safety Department University of Washington website, https://www.ehs.washington.edu/system/files/resources/EHS_Focus_Sheet_Em...

‘Empty Container Disposal’, Environmental Health and Safety, University of Colorado Environmental website, https://ehs.colorado.edu/resources/empty-container-disposal/ (1 November 2012)

Science ASSIST. 2018. Chemical Management Handbook for Australian Schools – Edition 3, Science ASSIST website, https://assist.asta.edu.au/resource/4193/chemical-management-handbook-au...

Science ASSIST. 2016. SOP: Diluting concentrated hydrochloric acid, Science ASSIST website, http://assist.asta.edu.au/resource/680/sop-diluting-concentrated-hydroch...

‘Chemical storage bottles’, Q&A Science ASSIST website, https://assist.asta.edu.au/question/3961/chemical-storage-bottles (21 July 2016)

‘Disposal of silver nitrate solid’, Q&A Science ASSIST website, https://assist.asta.edu.au/question/3017/disposal-silver-nitrate-solid (21 July 2015)

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