This might be a possible reason, I cant provide you with any reference regarding this. As fly ash is having a very low specific surface area and more over the possibility of trace elements and heavy metals make it a less preferred material for decontamination. And when it comes to decontamination adsorption plays a major role than absorption if i'm not wrong.

Thanks a lot, Sri Kanth, If you have gone through the paper cited in the link, you can know that an alkali activated fly ash gains in surface area and cation exchange capacity. Accordingly, the activated fly ash can be a potential material for decontamination. Still such material is awaiting for a place in the industry, for useful application. Hope you are in tune with me. I expect some more inputs from you. Awaiting for your response in near future.

I don't think there would be any change in the SSA. You might be knowing that Specific surface area(SSA) is a basic material property, it only depends upon the method you are using to determine the SSA and is independent of any other external agents. Maybe there is a possibility of improvement in the surface charge of the fly ash just like the way it happens in case of activated bentonites.

Thanks for your interest. I think you haven't done any test of this type. It happens and the result is astonishing, because of polymerization at nano scale level. In fact the fly ash particle is of macro-sizes while the activated fly ash is of meso-sizes in majority. Extensive research findings have confirmed this. I think you should refer to research papers, several papers are freely available online. Pl. reconnect in near future.

I worked on a few fly ash samples three years back for my masters but not anything like an activated fly ash and currently working on expansive soils(bentonite) for my PhD. My answers were based on my masters experience and nothing else. Thanks for the info. Just wanted to clear the air.

Thanks for such a swift response. I think you are deep inside research on Bentonite. Wish you all the best for your Ph. D., Thanks