"Because Venus lacks a protective magnetosphere, the upper atmosphere is exposed to direct erosion by the solar wind and has lost most of its original hydrogen to space."
Venus has a magnetosphere, although not as strong as Earth's. The problem with Venus' atmosphere, AFAIK, is that the heavier carbon dioxide layer is so thick that reaches the limit of that magnetosphere and in doing so it pushes the lighter molecules like hydrogen or even water to be exposed to the mentioned solar wind. If enough of that atmospheric carbon gets somehow fixated, then the freed oxygen should act as a capture net for all the solar wind's incoming protons and form water molecules (which, being heavier than oxygen, should then sink into lower atmospheric layers).
P.S.: I assumed only "enough" of carbon taken out of the atmosphere, so enough carbon dioxide should be assumed as left there untouched, which now with newly available water molecules should result in bicarbonate, carbonic acid, and other goodies, thus preserve Venus' traditional acidic environment, so no worries there! ;)
Venus has a magnetosphere, although not as strong as Earth's. The problem with Venus' atmosphere, AFAIK, is that the heavier carbon dioxide layer is so thick that reaches the limit of that magnetosphere and in doing so it pushes the lighter molecules like hydrogen or even water to be exposed to the mentioned solar wind. If enough of that atmospheric carbon gets somehow fixated, then the freed oxygen should act as a capture net for all the solar wind's incoming protons and form water molecules (which, being heavier than oxygen, should then sink into lower atmospheric layers).
P.S.: I assumed only "enough" of carbon taken out of the atmosphere, so enough carbon dioxide should be assumed as left there untouched, which now with newly available water molecules should result in bicarbonate, carbonic acid, and other goodies, thus preserve Venus' traditional acidic environment, so no worries there! ;)