Electrolysis for cleaning and stabilising (1 Viewer)

[mushroom_head]

* identify the use of electrolysis as a means of cleaning and stablising iron, copper and lead artefacts.

i couldn't find and info on lead! can someone please explain

 

[sHin]

Pb can form precipitates like Cu and Fe with Cl, so Pb can be reduced through electrolysis.

PbCl2(s) + 2e- --> Pb(s) + 2Cl-

 

[tennille]

They can all be stabilised in the same way. Lead, iron and copper all undergo electrolysis by making stainless steel as the anode, and the artefact as the cathode. The electrolyte varies depending on the metals used- if it's iron, usually NaOH is used as the electrolyte. When the voltage is applied, the Cl- and OH- ions are attracted to the anode, however, they do not undergo any reaction- they are just removed from the artefact. This is how they are cleaned.

 

[tennille]

When lead undergoes electrolysis, the electrolyte is 0.5mol/L of NaOH or Na2CO3. Before the lead artefact is immersed, the current should be turned on because lead hydroxide is soluble in alkaline solutions. If no current is flowing, lead oxide and lead hydroxide layers will dissolve in the solution. The lead ions that are contained in these layers are lost and therefore cannot be restored.

 

[mushroom_head]

Thanks Tennille

 

[Kazness]

http://hsc.csu.edu.au/chemistry/options/shipwrecks/2734/ch967Dec2_03.htm#b4

Thats were its at. All the best.

and here for even better explinations...

http://nautarch.tamu.edu/class/anth605/File0.htm

 

[Casmira]

also googling some aspects of electrolysis come in handy, i had a really complicated page on electrolysis of sodium chloride and i picked out some really good stuff (not all of it of course only relevant things)