Author Topic: Electric Charge, Rod Dia. Rod to Rod Distance.  (Read 1516 times)

Offline WayneInPHX

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Electric Charge, Rod Dia. Rod to Rod Distance.
« on: June 26, 2016, 06:16:04 AM »
Some questions for Kephra - I have read many articles here but none of them seemed to satisfy these questions:

A: I've gleaned from reading here that there is a minimum desired potential across the cell.  How is that calculated, taking into consideration the Rod-Diameter and Distance between them, etc?


B:  If the answer to A doesn't include WHY, please answer THAT here



C: Would running 3 mA instead of lets say 5 mA produce smaller nanoparticles?  How about 15, 20, 60??? 

D:  Do higher rates affect the  solution in ways OTHER than making it faster?  I.E.  I could make 20ppm in 15 min at 20mA, 6 min at 50 mA (all of course using a electrolyte AND assuming the solution will actually pass the current) 


D: 3 mA seems to be the number thrown around as a minimum.... Why?


E:  Very wide voltage ranges are used in the real world.  from 9 to as high as 40.   In my mind, It would seem that the smallest particles that one could make would be when the amperage and voltage are JUST above the threshold that allows ionic production.  I see it like arms in a pole pushing basketballs off itself.  Violent push ( High potential and high current) sloughs off several balls at a time where gentle pushes do only 1 at a time.  Am I envisioning this completely wrong?

TIA
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Offline kephra

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Re: Electric Charge, Rod Dia. Rod to Rod Distance.
« Reply #1 on: June 26, 2016, 11:25:37 AM »
Some questions for Kephra - I have read many articles here but none of them seemed to satisfy these questions:

A: I've gleaned from reading here that there is a minimum desired potential across the cell.  How is that calculated, taking into consideration the Rod-Diameter and Distance between them, etc?
It is calculated from the electrochemical series which gives the voltages needed to oxidize an element or reduce it.  This makes the minimum voltage 3.52 volts as explained in the articles if there is 100% conductivity in the solution.  But of course, there is not 100% conductivity in the solution and you cannot calculate it.  The solution conductivity depends on the amount and kind of electrolyte, the temperature, and the exact electrode geometry.  So the practical voltage must be above 3.52 volts.  Above 10 volts is a good practical rule.

Electrode geometry is not a factor in determining the minimum voltage of 3.52 volts.  Only the two metals involved, namely sodium and silver are determinant. 

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B:  If the answer to A doesn't include WHY, please answer THAT here



C: Would running 3 mA instead of lets say 5 mA produce smaller nanoparticles?  How about 15, 20, 60??? 
No. The size of the nanoparticles is determined by the reduction chemistry factors like the kind of reducing agent, temperature, pH.  However, the current does affect affect the rate that silver oxide is produced, and producing it faster than it can escape the boundary layer between the anode and the bulk water allows the silver oxide to precipitate instead of dissolving into the water.  Since larger anodes have a higher volume in the boundary layer, larger anodes help prevent the silver oxide to precipitate.

Quote
D:  Do higher rates affect the  solution in ways OTHER than making it faster?  I.E.  I could make 20ppm in 15 min at 20mA, 6 min at 50 mA (all of course using a electrolyte AND assuming the solution will actually pass the current) 
See C.
Quote
D: 3 mA seems to be the number thrown around as a minimum.... Why?
Practicality.  Very low currents require lower cell voltage. There is no concrete lower limit providing you adjust all the other parameters to fit.
Quote
E:  Very wide voltage ranges are used in the real world.  from 9 to as high as 40.   In my mind, It would seem that the smallest particles that one could make would be when the amperage and voltage are JUST above the threshold that allows ionic production.  I see it like arms in a pole pushing basketballs off itself.  Violent push ( High potential and high current) sloughs off several balls at a time where gentle pushes do only 1 at a time.  Am I envisioning this completely wrong?
Yes, its current which is the important factor.  However, its the voltage which creates the electric field between the electrodes, and its the electric field which drives ions from one electrode to the other.  Since the ideal is to quickly remove the silver ions out of the anode's boundary layer, a higher voltage for the same current is helpful in doing that.  If the ions are not removed quickly enough, they precipitate at the anode, and become visible as a brownish cloud.  Once precipitated, they are no longer moved by the electric field because the silver oxide particles have a net zero charge. 

This is all a big balancing act.  Everything you change affects everything else.  For example, If you change the electrode spacing, the conductivity between the electrodes change, and the electric field strength also changes.  Changing the amount of electrolyte also changes the conductivity, which affects the voltage needed to maintain a given current.  Changing the temperature affects everything.  Then there are practical considerations like having an electrode spacing that will actually fit in common flasks.

So some things can be exactly calculated like the amount of electrolyte per liter of solution, and some cannot be calculated but must be determined experimentally.  I worked out my recommendations based on the pH to produce the best zeta potential, reasonable electrode spacings, workable safe voltages, etc.  These recommendations produce excellent nanoparticles in the non-toxic and therapeutic range with no toxic byproducts.  Is this the only way to do it? No, but it works easily for the home colloidal silver maker.

« Last Edit: June 26, 2016, 01:11:16 PM by kephra »
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Offline WayneInPHX

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Re: Electric Charge, Rod Dia. Rod to Rod Distance.
« Reply #2 on: June 26, 2016, 03:48:13 PM »
THANK YOU! 8)
Most of us don’t listen with the intent to understand.  We listen with the intent to reply.  -  From a TED Talk

"I've decided I'm not old. I'm 25 plus shipping & handling!"

Offline WayneInPHX

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Re: Electric Charge, Rod Dia. Rod to Rod Distance.
« Reply #3 on: July 01, 2016, 05:53:33 AM »
Ya know,  Just when you think you have something figured out....

Well, I DID finally get my method to consistently produce very low Tyndall 20 ppm colloidal.  But not before being befuddled one last time.

Today, I tossed my first attempt because 10 minutes in, I had a noticeable Tyndall.  WTF?  I did everything right.  I squeaked the squeaker, click my heels twice, and did the chicken flap JUST LIKE BEFORE when it worked incredibly well!

Mulled over the sequence and said to myself "it is the same", except, I had removed, cleaned and reinserted my silver rods.  So WHAT was different I pondered.
Then I remembered the words of the all-knowing Kephra. "3.65 volts..."  Adjusted the (-) rod length till I had about 8 volts across the cell.   THAT worked... but, I'm still seeing more Tyndall than I had on that one magic batch.   Tried it again, only this time dropped the cell voltage to 4.5.  TA DA!

What has worked repeatable flawless is this:

                                                     12v PS, Pick your current and calculate bath time
                                                     Set the + rod full length
                                                      Adjust - rod to get about 4.5v cell voltage
                                                      Electrolyte at 8.5 PH using Sodium Carbonate and .2 Gram Maltodextrin reducer in at start
                                                      Start process, stirrer and heater - Stop heat at 145, then air-cool.  As time passes, the cell voltage gets close to 3.7

                                      RESULT:    A nice deep yellow with VERY low Tyndall and NO metallic taste... Every time.

Most of us don’t listen with the intent to understand.  We listen with the intent to reply.  -  From a TED Talk

"I've decided I'm not old. I'm 25 plus shipping & handling!"

indocomp

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Re: Electric Charge, Rod Dia. Rod to Rod Distance.
« Reply #4 on: August 04, 2021, 01:20:42 PM »
Hi im sorry i want to ask , you adjust the cathode so the voltage between 2 electrodes are 4.5 Volt eventhough you set the voltage at 10volt, am i right? and the longer the electrolysys process, it will near 10V eventually?
How if we start with 30 or more volt? do we still need to adjust the anode to 4.5 volt at beginning of the process?

Offline cfnisbet

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Re: Electric Charge, Rod Dia. Rod to Rod Distance.
« Reply #5 on: August 04, 2021, 05:57:55 PM »
No, you do not adjust the voltage across the electrodes to be 4.5 volts. The correct voltage difference across the electrodes is 10 volts; ideally more. 4.5 volts is not sufficient.

indocomp

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Re: Electric Charge, Rod Dia. Rod to Rod Distance.
« Reply #6 on: August 04, 2021, 08:30:58 PM »
it will be ok if i set maximum voltage like 30volts or more?
since i used 53 volts adaptor , so it will be ok if i atart with 53 volts ?

Offline kephra

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Re: Electric Charge, Rod Dia. Rod to Rod Distance.
« Reply #7 on: August 04, 2021, 09:37:41 PM »
Hi im sorry i want to ask , you adjust the cathode so the voltage between 2 electrodes are 4.5 Volt eventhough you set the voltage at 10volt, am i right? and the longer the electrolysys process, it will near 10V eventually?
How if we start with 30 or more volt? do we still need to adjust the anode to 4.5 volt at beginning of the process?
I don't know where you got 4.5  volts, but that is totally wrong.  For an electrode spacing of 37mm, the voltage should always be above 10 volts.  That is measured with the voltmeter connected directly to the electrodes.  Adjust the cathode up and down to get at least 10 volts.  More is better.  Wider spacings require more voltage as explained in the Articles.

Higher cell voltage pulls the silver ions away from the anode faster.

Read the articles.
There is the unknown and the unknowable.  It's a wise man who knows the difference.