Deterioration of ion exchange capacity
Deterioration of ion exchange capacity
(OP)
Hello,
I work on ion exchange resins on a laboratory scale.I regenerate the resin with Sodium salt of a particular concentration(Say 80 g /ltr of solution) and measure the capacity in terms of equivalents of ions detected per litre of the resin bed.
When i reduce the salt concentration in the regenerant by half (40 g/ltr of solution), the measured capacity is reduced by a factor of 4.Is such a drastic reduction acceptable?
Apart from the obvious change in salt concentration and resin degradation/fouling , are there any other factors that contribute to reduction in capacity ?
I work on ion exchange resins on a laboratory scale.I regenerate the resin with Sodium salt of a particular concentration(Say 80 g /ltr of solution) and measure the capacity in terms of equivalents of ions detected per litre of the resin bed.
When i reduce the salt concentration in the regenerant by half (40 g/ltr of solution), the measured capacity is reduced by a factor of 4.Is such a drastic reduction acceptable?
Apart from the obvious change in salt concentration and resin degradation/fouling , are there any other factors that contribute to reduction in capacity ?





RE: Deterioration of ion exchange capacity
m777182
RE: Deterioration of ion exchange capacity
RE: Deterioration of ion exchange capacity
however, all things are not equal. in resin regeration, you are typically relying on a complete saturation of the resin. frequently, you are regenating with something the resin would rather not have. in your case, if you put a mixture of calcium chloride and sodium chloride through a resin that had been regenated with acid (H+), it would preferentially remove the calcium.
with regards to valence, the Ca++ is why the ppm levels of the calcium "stick" better than equivalent ppm level of Na+.
when the regenerant conc. is cut in half,this becomes more of a kinetics/equilibrium question.
water treatment systems will frequently try and increase regenerant volumes and concentrations to try and compensate for fouling of the resin.
RE: Deterioration of ion exchange capacity
You must trust me, if I say, I have been waiting for somebody to negate my comment after I posted it.
At first thought this didn't seem to me as a problem with degradation or fouling as that should have effected when we used actual concentration also. Then I required a quick answer and thus I overlooked simple algebra. Further, I thought that the original poster was comparing both the results with respect to inlet concentration (yes, I agree that it is a silly idea and includes some magical numbers)
Having said this, I still feel it is natural. As you already stated in your reply that a bivalent ion has greater tendency to stick to the resins than a monovalent ion and we do reuire strong concentration to reverse the effect.
Thanks for pointing out.
Regards,