Abstract: The invention relates to a process for producing an adsorbent material containing iron oxyhydroxide, wherein an iron oxyhydroxide mass having a moisture content of 5-15% by weight is produced, said mass is granulated by compaction, followed by comminution and sieving of the compacted product to give product granules with grain sizes ranging between 0.5 and 4 mm. The invention is also relates to a granular adsorbent material containing iron oxyhydroxide, the grain size of the granules being between 0.5 and 4 mm, and the bulk density thereof being from 0.8 to 1.5 g/cm3. Said adsorbent material may be used for removing harmful substances, particularly arsenic, from an aqueous solution thereof.