Chemicals, Carbon Filters and Resin Activation

1. Your activated carbon is exhausted. You'll need to replace it and send it for regeneration.
2. The UV lamp ionized the chlorine to form hydrochloric acid.

The chloride ion formed is removed by deionization, hence no lowering of pH.

Carbon is not a resin, it is an element with the ability to adsorb certain chemicals. Steam is commonly used to re-activate carbon. I don't know your system so it may not be practical for you.

I don't know your system or the process in which you are using it, but in general activated carbon can be regenerated by either vacuum or high temperature.

In gold extraction, medium pressure steam is used as the temperature increase activates better than the pressure increase reduces activation.

depending on what contaminates you are removing, any temp increase or pressure reduction will encourage desorption of the contaminant and regeneration of the carbon.

Your carbon supplier can probably advise on the best approach for your situation, or even recommend a different carbon. Different carbons adsorb and desorb differently, eg coconut husk carbon has somewhat different characteristics to petroleum based carbons.