Is there a word for a person who is in search of knowledge?

Yes, in a Word: intelligent. As Alexander Pope wrote, "...the proper study of mankind is man." (A pox on political and gender Bowdlerisms!)

But there are subtleties in the type of knowledge available and the terms used to describe those who search for it.

A student, if the knowledge is of an educational nature, whether or not formally structured.

A seeker, if the knowledge is of a spiritual, mystical, ontological or metaphysical nature.

A postulant, if the knowledge is of a religious nature and the person is a candidate or an applicant to enter a religious institution.

A novice, if the knowledge is general and the person is a beginner in its practice.