Do Some Carbon Filters Remove Chloramines, While Others Don't?

Question

I thought that carbon filtration removed both chlorine and chloramines from water. However, the seller of a reverse osmosis system on Amazon answered a question with this:

This system can remove up to 99% of chlorine. A different inline filter will need to be added in order to remove Chloramines as well.

This particular unit has two carbon filters, one in the beginning and one in the end, both are:

Premium Quick-Connect coconut shell activated carbon filter. Nominal 5 Micron Rating GAC Acid Washed Carbon

Are there different types of carbon filters, some that would filter out chloramine and some that do not?

Edit: I received a response from the seller:

Standard carbon filters can remove traces of chloramines from a water source, but to effectively remove it up to 99%, you would need a carbon filter that uses "catalytic carbon" media inside it.

Answer 1

'Are there different types of carbon filters, some that would filter out chloramine and some that do not?'

Sort of. As long as you're dealing with activated carbon filters they will provide the necessary components for the chemical reduction of chloramine. The difference , though, is whether or not they provide the necessary surface area of activated carbon or the correct flow rate to effectively reduce it in one pass. My guess, then, is that (at least in the eyes of the seller) this unit has either insufficient surface area or too high a flow rate to effectively reduce chloramines in the single pass.

~edit~

For a good review of chlorine and chloramines and methods for their removal, see this article.

~edit ii~

This book specifically makes mention of coconut-shell carbon filters, in reference to differences in filtration performance based on carbon source:

'Charcoals from different sources differ in their adsorbtive capacities and the types of substances that they remove best. Bituminous coal, anthracite or coconut shells, as examples, are pyrolysed, giving products that are predominantly microcrystalline graphite.'

Unfortunately it doesn't expand on specific differences between various sources, but it does suggest that the carbon source itself could account for some variation in expected performance.

Answer 2

I received an email from the seller and will post it as a potential answer:

Standard carbon filters can remove traces of chloramines from a water source, but to effectively remove it up to 99%, you would need a carbon filter that uses "catalytic carbon" media inside it.