You don’t need to use bone char for fluoride removal since the bone char is just creating more solid waste. You can reversibly use adsorbents that can transfer the fluoride in the water to a usable product such as Calcium Fluoride, and the adsorbent can be used indefinitely.

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Hi Rakesh - What's not shown here and only alluded to in this article is that, in tandem, we are building a bone char regeneration facility. F sorption to bone char is (mostly) reversible, so we remove it to regenerate the bone char's F sorption capacity and then the char is used again for water treatment. Our testing so far has shown recovery of sorption capacity at least out to a dozen cycles of regeneration.

We do like you say with the regenerant solution - precipitate calcium fluoride to immobilize the F and prevent it from returning to the environment/water as a contaminant.

This can also be done with other sorbents as you indicate such as alumina. But under these water geochemical conditions our bone char way out-performs alumina for F uptake. Thus we have a longer life-cycle between regenerations.

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