October 20, 2019, 02:16:27 AM
Forum Rules: Read This Before Posting


Topic: Electrolysis of Salt water with aluminium anodes  (Read 13003 times)

0 Members and 1 Guest are viewing this topic.

lordofdarkness

  • Guest
Electrolysis of Salt water with aluminium anodes
« on: June 18, 2005, 10:30:52 PM »
What are the products of the electrolysis of saltwater using aluminium for anodes"?

Offline constant thinker

  • mad scientist
  • Sr. Member
  • *****
  • Posts: 1275
  • Mole Snacks: +85/-45
  • Gender: Male
Re:Electrolysis of Salt water with aluminium anodes
« Reply #1 on: June 18, 2005, 11:11:56 PM »
I'm not sure on this one but it wouldn't be to safe if the Cl and Na parted ways. You'd have chlorine gas and a volatile compound that'll want to react. Plus you'll get hydrogen in a rich oxygen enviroment (because of the O coming from the H20). Doesn't sound safe to me.
"The nine most terrifying words in the English language are, 'I'm from the government and I'm here to help.' " -Ronald Reagan

"I'm for anything that gets you through the night, be it prayer, tranquilizers, or a bottle of Jack Daniels." -Frank Sinatra

Offline xiankai

  • Chemist
  • Full Member
  • *
  • Posts: 786
  • Mole Snacks: +77/-37
  • Gender: Male
Re:Electrolysis of Salt water with aluminium anodes
« Reply #2 on: June 19, 2005, 01:55:45 AM »
at the cathode u'll obtain hydrogen (nothing to do with the atmosphere, just the water in the your solution)

2H+ +2 e- --> H2

and at the anode u'll obtain chlorine or oxygen, depending on the  concentration of chloride ions because there are 2 possible reactions

4OH- --> 2H2O + O2 + 4e-

or

2Cl- --> Cl2 + 2e-

aluminium being oxidised is a small possibility, because its oxide layer prevents it from participating in the reaction.

one learns best by teaching

Offline Borek

  • Mr. pH
  • Administrator
  • Deity Member
  • *
  • Posts: 25239
  • Mole Snacks: +1658/-398
  • Gender: Male
  • I am known to be occasionally wrong.
    • Chembuddy
Re:Electrolysis of Salt water with aluminium anodes
« Reply #3 on: June 19, 2005, 05:50:26 AM »
aluminium being oxidised is a small possibility, because its oxide layer prevents it from participating in the reaction.

In case of water hydolysis OH- will dissolve oxide layer as aluminum is amphoteric.

No exact idea about what will happen on the electrode surface if the chlorine evolves, but I doubt aluminum anode will survive long in such environement.
ChemBuddy chemical calculators - stoichiometry, pH, concentration, buffer preparation, titrations.info, pH-meter.info

Offline jdurg

  • Banninator
  • Retired Staff
  • Sr. Member
  • *
  • Posts: 1366
  • Mole Snacks: +106/-23
  • Gender: Male
  • I am NOT a freak.
Re:Electrolysis of Salt water with aluminium anodes
« Reply #4 on: June 19, 2005, 07:45:44 PM »
The Aluminum won't last long at all.  As the electrolysis takes place, you'll be forming a fairly strong sodium hydroxide solution which will eat away at the aluminum forming a lot of hydrogen gas.  You'll also have the chlorine gas reacting directly with the aluminum where the oxide layer has been eroded away.  Finally, the little bits of HCl that form as a result of the dissolution of chlorine gas will eat away at the aluminum as well.
"A real fart is beefy, has a density greater than or equal to the air surrounding it, consists

Offline Edaw

  • New Member
  • **
  • Posts: 3
  • Mole Snacks: +0/-0
Re: Electrolysis of Salt water with aluminium anodes
« Reply #5 on: July 05, 2018, 10:06:33 PM »
I'm doing this as well and I'm a little worried that Aluminum Chloride could be created through this, am I safe or should I not continue with using aluminum as my anode?

Offline Enthalpy

  • Chemist
  • Sr. Member
  • *
  • Posts: 3101
  • Mole Snacks: +275/-57
Re: Electrolysis of Salt water with aluminium anodes
« Reply #6 on: July 06, 2018, 07:31:13 AM »
For aqueous electrolysis, don't use aluminium electrodes. You'd only get an ugly mess. Take stainless steel or graphite. Saline batteries contain a graphite electrode which you can extract, if minding the other compounds in the battery.

Electrolysis of salt water: no, you are NOT safe. This is not a matter of electrodes. Salt water electrolysis releases chlorine and hypochlorite, and both are harmful. It's a matter of ventilation and of production rate. A simple base like NaOH would be better.

Offline Borek

  • Mr. pH
  • Administrator
  • Deity Member
  • *
  • Posts: 25239
  • Mole Snacks: +1658/-398
  • Gender: Male
  • I am known to be occasionally wrong.
    • Chembuddy
Re: Electrolysis of Salt water with aluminium anodes
« Reply #7 on: July 06, 2018, 03:02:48 PM »
Necroposting record in a 13 years old thread. Locking, please continue here: http://www.chemicalforums.com/index.php?topic=96098.0
ChemBuddy chemical calculators - stoichiometry, pH, concentration, buffer preparation, titrations.info, pH-meter.info

Sponsored Links