ACIDIC AND BASIC MODIFICATION OF NATURAL PUMICE TO IMPROVE ITS PROPERTIES FOR BIOLOGICAL APPLICATIONS

Pumice (PM) is a natural volcanic aluminosilicate mineral having a spongy, porous structure with great hardness. The activation of PM to enhance its purity and adsorption capacity is mostly investigated for water purification and construction fields. However, the effects of the chemical activation processes on PM properties have not been investigated for biological applications specifically. Therefore, this study aims to elucidate the effects of chemical activation of natural PM on its microstructural, chemical and biological properties. The micronized Cappadocia PM (from Turkey) was activated by respective treatments of 1M of hydrochloric acid (HCl) and 1M of sodium hydroxide (NaOH) solutions. To identify the impact of chemical treatments, natural pumice (PM) from Cappadocia, acid-modified PM (PM+HCl), and acid-base-modified PM (PM+HCl+NaOH) samples were investigated comparatively. X-ray Fluorescence (XRF) analyses results showed the removal and reduction of some trace metal impurities. The morphological images also revealed purification of surface from small soluble ions and improved surface area, porosity and interconnectivity. Furthermore, evaluation of cytotoxicity towards normal human fetal osteoblasts (hFOB 1.19 cells) showed that the chemical activation steps have supported cell viability. Therefore, chemical activation of natural PM with tailored surface structure stimulating better ionic exchange and cytocompatibility enhances its potential for Biotechnology and tissue engineering applications.