A Sephadex gel filtration column with a cutoff of a least 50kDa (e.g. G-50) or more should separate the proteins. Be sure to use a long column for high resolution purification.

Alternatively, you can use columns like the superdex 10/300 GL.

I would recommend a Superdex 75 SEC column which has a good resolution in the range of these MWs. The Sephadex G50 could be limited due lower resolution in this size range (you can find different ranges for the exclusion size). The Superdex column is more expensive, so you could try the cheaper one first.