Letter 13077

Ion exchange resin regeneration 

How effect would lime regeneration of anion exchange resins be? Apart from calcium sulfate deposition would I encounter any other difficulties?

Ranjit M
- Mumbai, Maharashtra, India

Basically (pun intended) it will be very inefficient and likley will not work at all. You would have to filter to an extremely high degree the lime slurry so that it was essentially free of suspended solids. If you do not, it will foul the resin bed very very quickly. Further, the typical pH of lime slurry (and an indicator of hydroxyl strength necessary to effect the regeneration process) is fairly low as compared with sodium hydroxide at 4%. I believe the best you will probably get is around a pH of 11 or so - and weak at that.

There isn't much way around the fact that you need a heavy basicity and caustic soda is the best reagent for it.

Tom Baker       wastewater treatment specialist Warminster, Pennsylvania

Don't bring lime near your resin unless you intend to manufacture black speckled plaster for that different look.

John Tuohy
- Ireland

dear sir,
I'm currently doing study on water minimisation in a chlor alkali plant. can u tell what is the limiting concentration (pH, TDS hardness) for feed water for ion exchange regeration.I want to reduce the amount of fresh water use by replacing with wastewater from another process.
tq

Yasmin Abdullah
student - Malaysia

how to regeneneration the mixed bed

Msatheeswaran
- Salem Tamilnadu, India

I am a final year student of Civil Engineering at Obafemi Awolowo University, Ile Ife, Osun State, Nigeria. I am doing my project on removal of hardness using the ion exchange process. I need information on how to determine the capacity of an ion exchange resin and more importantly how to tell that the column is exhausted and needs recharging. Please I need this information badly and fast. Can you help me?

Jephthah Efereyan
Obafemi Awolowo University - Ile Ife, Osun, NIgeria

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