'pure interest' is correct and usable in written English.
You can use it to describe a situation in which an individual (or group) is motivated only by curiosity or a desire to learn. For example: "John went to the lecture out of pure interest, not expecting any external rewards."
They tried to pretend it was a serious debate, but it was pure interest politics.
Lacking the pressure of a plot, these passages stake everything on their pure interest as writing.
In terms of pure interest -- as it relates to what people were searching for during the debate -- there's no question this was a good night for Sanders.
Out of pure interest, Dalio had also been trading his own account on the side since graduating HBS.
Different fourth-year medical students rotate monthly, ranging from those interested in pursuing EM residency to those rotating to complete school credits or out of pure interest.
By this time in their careers, most of them have already decided to be doctors or optometrists, so the pure interest that these subjects could have generated in them at a younger age has been extinguished and replaced by a purely professional drive.
And that offsets any underlying effect of the pure interest-rate effect going up.
A Federal commission developing a cyber-tax policy includes not a single person who represents the pure interests of the customer.
The drivers noted that they, alongside the fans, had the "purest interest" in F1 but insisted that the structure at the top needed to change: "We would like to request and urge the owners and all stakeholders of Formula One to consider restructuring its own governance".
Colloidal semiconductor nanocrystals have evolved in the past decades from a topic of pure scientific interest to a technological one.
"The 2008 banking crisis demonstrated what happens when we allow banks to act out of pure self interest.
