Can a lubricating oil purifier be used as a diesel oil purifier?

No! It will not work as a purifier works using central fugalforce (spins dirty fuel to the outside). Lubricating oil is heavier so it cant be used. On marine purifiers any dirty fuel is dumped into a sludge tank after the sensor realises there is more than 15 parts per million. If you were to use lubricating oil the sensor will dump all of it as it is too thick.