Commercial and recycled HIPS were used for the preparation of flat-sheet membranes. Structural changes and permselectivity of membranes were successfully studied. The HIPS-R membranes showed higher permeate flux and a more porous structure. The HIPS-R membranes confirmed better antifouling capabilities than HIPS membranes. The HIPS-R membranes presented higher humic acid rejection than HIPS membranes.