US 43563774 A description to facilitate understanding the treatment of a stream of a synthetic crude with the particles of the material for removing the contaminant will be described hereinafter the drawing shows one embodiment within this invention wherein fresh feed in pipe 1 has added thereto fresh makeup particles of iron etc if any is added by way of pipe 2 hydrogen by way of pipe 3 and any recycle slurry by way of pipe 4 after which the resulting mixture enters reaction zone 5 wherein it is heated and the contaminants deposit out on the particles present in the mixture the mixture then passes by way of pipe 6 to separation zone 7 wherein hydrogen containing gas is removed from the mixture by way of pipe 8 essentially contaminant free oil is removed as the product of the process by way of pipe 9 and the remaining slurry of liquid and particles is removed by way of pipe 10 for removal from the system or recycle in pipe 4 or a combination thereof in carrying out this invention the particles of material are injected into the feed stream of synthetic crude to remove the contaminant of arsenic or selenium whether in elemental or combined form the particles of material preferably have a surface area of at least 1 square meter per gram still more preferably having a surface area of at least 50 square meters per gram the active ingredient such as the iron oxide or iron sulfide for example the crushed and sieved pellets of a conventional carbon monoxide shift catalyst can be employed by itself in the particles or may be employed in combination with a conventional support carrier such as silica alumina magnesia zirconia thoria.