Activation of a sepiolite with dilute solutions of HNO3and subsequent heat treatments: III. Development of porosity

Abstract
Porosity development in a sepiolite from Toledo, Spain, has been studied as a function of acid (0·25, 0·50, 0·75 and 1·0mHNO3) and subsequent heat treatments (110–400°C). Adsorption isotherms of N2at 77 K have been analysed byf-plot,t-plot,αs-plot and the Cranston & Inkley methods. Results are compared with those obtained on products heated without previous acid activation. Experimental conditions favouring porosity development are discussed.