Hydrogen adsorption on natural and sulphuric acid treated sepiolite and bentonite

In this study, hydrogen (H2) adsorption on sepiolite and bentonite and those of acid treated forms were studied at 77 K using volumetric apparatus up to 100 kPa. Both clay minerals were treated with 100 ml of 0.5, 1.0, 2.0 and 4.0 M H2SO4 solutions at 80 °C for 5 h. Differences in the structures of the sepiolite and bentonite samples before and after the acid treatments were determined by XRD, XRF, TG, DTA and N2 adsorption methods. The level of H2 adsorption of original and acid treated sepiolite samples (1.332-2.252 mmol/g) was higher than those of the bentonite samples (0.341-1.003 mmol/g). The variation in the H2 adsorption capacities during the acid treatment was also discussed.