The present invention relates to a method of manufacturing a treated material having adsorbent properties, the method comprising heating a starting material which is a waste product comprising organic matter so as to form a treated material, wherein the starting material comprises a waste product formed during a decolourisation process, e.g. a sugar refining process. The invention also relates to adsorbent material produced or producible by the method, and to uses thereof for either decolourising a solution comprising a carbohydrate to be refined, or for absorbing SOx and/or NOx from a gas stream. The method further relates to a surgar refining processes in which the process results in the production of the waste stream and uses the treated material formed therefrom.