The EU is working on specific recommendations for Russian passports distributed in Donbas. The action plan of the European Commission is notifying that the member states will not recognize those passports.
The final decision on this issue will depend on the EU member states themselves. The first country declared non-recognition of Russian passports was Estonia, and the next day a similar decision was taken by Lietuva and Latvia.
The main tool for denying passports of the population of Donbass will be denial of Schengen visa.