How to Kill the COVID-19 Virus

By the middle of 2020 millions of people had been infected with a virus which causes a disease known as COVID-19 and hundreds of thousands of people had died.

So I was intrigued when I read that Professor Mary-Louise McLaws, an infection control expert from the University of New South Wales, had stated that, "it's relatively easy to kill compared to some other viruses".

Why is the COVID-19 virus easy to kill and how do you kill it? 

Read this edition of AUS-e-NEWS to find out more.

Subscribe to AUS-e-NEWS at https://www.ausetute.com.au/ausenews.html

Dangerous Chemical Spill at Lucas Heights

This is a headline from the Sydney Morning Herald, Friday 1^st March 2019, "Three hospitalised after chemical spill at Lucas Heights nuclear facility" and an excerpt from the newspaper story is below:

"Two men in their 30s, and a woman, 26, were injured when a cap came off a pipe at the Australian Nuclear Science and Technology Organisation facility at Lucas Heights, spilling about 250 millilitres of sodium hydroxide, also known as caustic soda, onto their arms and faces.

 Sodium hydroxide, also known as caustic soda, is corrosive to the skin and eyes and can cause severe burns."

This "sodium hydroxide" or "caustic soda" sounds like really dangerous stuff doesn't it?  I mean to say, it must be if just 250 mL (a quarter of a litre, a bit less than half a pint)  causes 3 people in an up-to-date, modern, nuclear-medicine manufacturing building, to be hospitalized!

 Well, sodium hydroxide is a caustic substance, that is, corrosive to skin, and it is dangerous if handled incorrectly, however, it is also readily available to non-scientists! You will probably find sodium hydroxide in your own home.

Sodium hydroxide is commonly found in household cleaning products that are used to unblock drains. One such product is Mr Muscle Drano  The directions for use including the following:

WEAR EYE PROTECTION AND PROTECTIVE GLOVES WHEN MIXING OR USING. AVOID CONTACT WITH EYES AND SKIN. DO NOT MIX WITH HOT WATER. 

Keep hands and face away from drains and wash hands after use. Ensure adequate ventilation.
• Do NOT mix with other cleaning products or acids as it may give off a dangerous gas
• Open carefully, do not squeeze the bottle, avoid splashing and clean up spills at once.
• Never use a plunger during or after use, as there may be some Mr Muscle® Drano® in the pipe if the blockage did not completely clear.
• Do NOT use in spas, dishwashers, washing machines, rubbish disposals, toilets or any pipes leading to these outlets. Will not remove roots, leaves or non-organic matter. Always refer to product label for full directions.

You will find sodium hydroxide pellets ("crystals") are also readily available, the website of one such product even suggests you use it to make your own soap ...

METHOD 

1. READ THE DANGEROUS GOODS INFORMATION BELOW BEFORE BEGINNING THIS RECIPE. 

2. Pour cold water into the plastic jar. 

3. Measure Glitz Caustic Soda (into a dry plastic cup).

 4. Slowly and carefully add the Glitz Caustic Soda to the cold water, stirring continuously with a plastic rod. (Wear plastic gloves and goggles; test gloves for holes first.) Do not breath the vapor or lean over the container or have children nearby. The mixture will get very hot.  

5. Allow the solution to cool down to a warm temperature (approx 40oC) in a safe place. 

 6. Melt the Coconut Oil (Copha) at a low heat in a stainless steel saucepan. Add the Canola Oil and Olive Oil to the melted Coconut Oil. Mix well 

7. Allow the oil mixture to cool down to a warm temperature (approx 40oC)

 8. Slowly and carefully, pour the Caustic Soda solution into the stainless steel saucepan containing the oil mixture. Mix thoroughly for at least 30 minutes or until it looks like thick pudding. 

9. If desired, select one fragrance from the optional fragrances. Add the fragrance to the soap mixture and mix for a further 30 minutes.  

10. Pour the finished soap into the tupperware container and allow 24hrs of setting. 

11. Cut the set soap into bars and leave it to cure for at least 6 weeks before use

But honestly, making your own soap at home might sound like fun, but unless you fully understand what you are doing then you should NOT use your soap to wash yourself or you might be the one that is rushed to hospital!

Suggested further reading:
Properties of Acids and Bases 
Definitions of Acids and Bases 
Strength of Bases
Heat of Solution
Neutralisation Reactions 
Heat of Neutralisation
Safety in the Lab 
Soaps and Saponification

Suggested Study Questions:

1. Sodium hydroxide is a caustic substance. What GHS (Globally Harmonised System) pictogram would you find on a container of sodium hydroxide.
2. Sodium hydroxide is a caustic substance. What personal protective equipment (PPE) should you use when handling sodium hydroxide?
3. Write a set of instructions, including all required safety precautions, for dissolving 1 g of sodium hydroxide in 1 L of water.
4. Consider the instructions for using Mr Muscle Drano. Why do you think it advises you to NOT use the product in dishwashers, washing machines and toilets?
5. Consider the instructions for using Mr Muscle Drano. Why do you think it advises you to use ONLY in well ventilated areas?
6. Consider the instructions for making soap. Should you use a plastic drinking cup from the kitchen to measure out the caustic soda? Explain your answer.
7. Why do the soap-making instructions tell you to add the caustic acid to the water AND NOT tell you to add the water to the caustic soda? Do you think it matters which you do this step? Explain your answer.
8. The soap-making instructions tell you to use a stainless steel saucepan. Do you think it would matter if you used an aluminium saucepan or a glass saucepan? Explain your answer.
9. Do you think it is advisable to use a saucepan from the kitchen to make soap? Explain your answer.
10. Imagine you were at the Lucas Heights facility when 3 of your co-workers were injured in this chemical spill. What would you do first to help them?

Sticky Surfactant?

 How often have you found that, no matter how hard you try, it is impossible to get that last bit of detergent out of the plastic bottle? Do you turn the bottle upside down and wait, letting the cleaning stuff flow to the bottom, but then find there is still some left no matter how hard you squeeze the bottle? Do you then try adding a bit of water and shaking it so that you can extract just a little bit more of it out of the bottle? And then, do you eventually give up and finally chuck the bottle away, still containing a very small amount of the cleaning product?
Well, if you find this sticky surfactant problem unsatisfactory, you aren't alone!
 The reason why it is so hard to remove ALL the detergent from the bottle is the same reason why the detergent makes a good cleaning product, that is, surfactant molecules have a long non-polar chain that attracts other non-polar substances like oils and grease, and a polar or ionic head that attracts other polar substances like water. So, if you pour a detergent, containing surfactant molecules, into a non-polar plastic container like polyethylene or polypropylene, the non-polar parts of the surfactant molecule will be attracted to the non-polar surface of the bottle making it hard to get all the surfactant molecules out of the bottle.

But scientists at The Ohio State University have now developed a way to make the plastic bottles so that ALL your shampoo or "liquid" detergent will flow out of the bottle. It involves spray-coating the surface of the plastic with a solvent and ultrafine silica nanoparticles. The solvent softens the plastic enabling the silica to be embedded in the  surface formed "Y" shaped channels a few micrometers high and a few micrometers apart. The branches of the "Y" shapes overhang the plastic surface at an angle of less than 90 degrees resulting in trapped air. Surfactant molecules are then in contact with air rather than plastic so that they can form spherical beads that will roll off.

The university hopes to further develop this process and license the coating technique to manufacturers, not just for shampoo bottles, but for other plastic products that have to stay clean, such as biomedical devices or catheters.

Reference: 

Ohio State University. "Shampoo bottle that empties completely, every last drop." ScienceDaily. ScienceDaily, 27 June 2016.

Further Reading:

Soaps
Detergents
Wetting
Intermolecular Forces
Nanoparticles and Nanotechnology
Molecular Formula
2-Dimensional Structural Formula
Condensed (semi-structural) formula
Skeletal Formula
Introduction to Functional Groups
Carboxylic Acids


Suggested Study Questions

1. A typical soap molecule, sodium stearate is shown below:
   
   • Draw the full 2-dimensional structural formula for this molecule
   • Write the condensed (semi-structural) formula for this molecule
   • Write the molecular formula for this molecule
2. Draw the skeletal formula for potassium stearate:
   • draw a ring around the functional group
   • name the functional group
   • describe the non-polar part of the molecule
   • describe the polar part of the molecule
3. Draw a structural formula for stearic acid.
4. Write a chemical equation for the neutralisation of stearic acid using sodium hydroxide in aqueous solution.
5. Describe how soap removes dirt during washing.
6. Sodium dodecyl sulfate shown below is a common surfactant molecule found in detergents
   
• Draw the full 2-dimensional structural formula for this molecule
• Write the condensed (semi-structural) formula for this molecule
• Write the molecular formula for this molecule
7. Draw the skeletal formula for potassium dodecyl sulfate:
   • draw a ring around the functional group
   • name the functional group
   • describe the non-polar part of the molecule
   • describe the polar part of the molecule
8. Explain why sodium dodecyl sulfate is classified as an anionic detergent.
9. Compare molecules of sodium dodecyl sulfate and sodium stearate
   • Desribe any similarities between the two molecules
   • Describe any differences between the two molecules
   • Explain how both molecules can be used to remove dirt during washing
10. Consider the problem of detergent sticking to the inside walls of the plastic bottle.
    • Describe the physical properties of the plastic bottle that enable this to happen
    • Use a diagram to help explain why the detergent molecules can "stick" to the plastic bottle
    • Use a diagram to explain why adding water to the not-quite-empty plastic bottle allows more of the detergent to be removed

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