Is it obligatory to donate the value of the usurious interest that has been benefited from, and does this interest remain unlawful in the present money and not in the essence of the money, and is it permissible to spend it on buying Qurans and distributing them to non-Muslim girls?

If you used usurious gains before you knew of their prohibition, then there is no blame upon you, and you are not required to give out a substitute for what you consumed of them; for the Lawgiver differentiates between one who is ignorant and one who is aware of the prohibition. However, if you were aware of their prohibition but took them due to negligence, then you must give out a substitute from your own money and spend it on charitable causes, such as giving charity to the poor and needy or for public welfare.

As for purchasing copies of the Qur’an with that money for non-Muslim women, it is not permissible; because the general principle is that a disbeliever should not be given a copy of the Qur’an for fear of its desecration, just as it is not permissible for a disbeliever to touch a copy of the Qur’an.