Effect of the acid type on clinoptilolite-rich tuff for hydrogen storage

Clinoptilolite from Gördes (Turkey) was treated with HCl, HNO3 and H2SO4 solutions of varying concentrations (from 2.0 M to 6.0 M) at 90 °C for 4 h to evaluate its potential for possible applications in hydrogen storage. X-ray diffraction, X-ray fluorescence and nitrogen adsorption techniques were applied for characterization of the zeolites. Hydrogen adsorption capacities of clinoptilolite samples were found in the range between 1.609 and 2.391 mmol/g. The effects of the acid modification process on the structure and hence hydrogen adsorption was evaluated according to the obtained results. •Hydrogen storage capacities were investigated at 77 K using volumetric apparatus.•Structural changes of clinoptilolite were determined by XRD, XRF and N2 adsorption.•CLN-2N sample showed highest hydrogen adsorption capacity (0.482 wt %).