Studies in adsorption. XVI The measurement of specific surface areas of finely divided solids by solution adsorption

Abstract Solution adsorption of p ‐nitrophenol at room temperature is suitable for specific surface‐area measurements on a wide variety of solids, including carbon, cement, coal, fibres, organic pigments and water‐soluble materials, e.g., sugar. The experimental procedure is simple, and the results with a variety of organic and inorganic solids are generally in good agreement with those given by the nitrogen adsorption method. With most materials, water is the most suitable solvent, but a non‐aqueous solvent, e.g., xylene, is used with water‐soluble solids. An anthraquinone acid wool dye (C.I. Acid Blue 25) gives good results from water on inorganic oxides and with these it is simpler to use than p ‐nitrophenol. In general, however, dyes though convenient in use, do not give reliable results except for comparison of the areas of different samples of the same material.