Why not use a cutter rather than a saw or a sander.
In more details, it the title is not enough.
I think a sander is likely to remove wood as easily as it does
paper, possibly more easily. Thus it is not clear that you will get a
clean job.
You might get a better result by clamping the pages between two pieces
of some hard metal, like iron. Aluminum or other soft metals might not
work as well.
Then, the pages may still stick a bit together, as they would with
sawing. But it should be enough if all you want is scanning.
However, extending your question to other solutions:
Another suggestion may be to use a cutting press, as was done by
bookbinders for trimming pages when mechanical paper guillotine, such
as hydraulic book trimmers were not available. Professional
bookbinders used to do excellent and precise work centuries ago, which
was particularly necessary when they wanted to apply a gold finish on
page edges. This is still practised by amateur bookbinders.
Basically it simply replaces the saw by a knife. You need just a very simple press to hold the pages and
compress them. One edge of the press must be flat and wide enough so
that you can hold a cutting tool against it in order to keep the the
blade perpendicular to the stack of pages. The cutting edge itself
makes an angle, as is often the case when cutting with a blade. You
cut the page stack progressively in many passes, a few pages at a
time.
The basic procedure is described in this video,
https://www.youtube.com/watch?v=X9EZhXQ1p1c , but I am sure you can
find many others on bookbinding sites, or in books about bookbinding,
if you look for "page trimming".
This video gives you the essential. But the blade may have a different
shape. Actually, when I learned to do that a very long time ago, I
think I used my leather paring knife. It is a simple blade composed
of a flat piece of steel about an inch or two wide, sharpened on one
end by grinding it only on one side (the other side must be perfectly
flat, as i rests on the edge of the press to guide the cutting). The
grinding is done so that the cutting edge makes an angle of about 45
degrees with the the non cutting edge (I was taught to make my own
blades).
Now, it you are just removing the binding, and not looking for a
perfect job, my guess is that a cutter could do the job just as well. Just don't try
to cut too many pages with each pass of the blade.