Acid activation of a palygorskite with HCl: Development of physico-chemical, textural and surface properties 

 -  Applied Clay Science, 10(3), p.247-258, 1995 .
<br/><br/> A palygorskite from Bercimuel (Segovia, Spain)was treated with 1.0,3.0,5.0 and 7.0 N solutions of HCl for 1 hour under reflux. The solids obtained were characterized by XRD, FT-IR spectroscopy, thermal <analyses, TEM and nitrogen adsorption-desorption isotherms at 77 K. The acid treatment runs with the removal of the octahedral cations -Mg( II), Al( III)-and the formation of amorphous silica from the tetrahedral sheet. An important increase in the specific surface area was observed during treatment, reaching a maximum of 286 m2/g in the sample treated with 5.0 N HCl. The silica obtained after the treatments maintains the fibrous morphology of natural palygorskite. No creation of microporosity is observed during the treatment.