Functional Gradient Adsorbents Processed with Biogenic Components for Ecologically Benign Water Purification

The topic of this paper is to review some results of laboratory examinations of mostly volcanic aluminosilicates (clinoptilolite-rich tuffs, tephra, stilbite, alginite, montmorillonite, perlite product vapex) deposited in Slovak and some Chinese repositories, which were achieved during scientific cooperation. The overview is limited and highlights only those results which concern Pb(II), Al(III), PO4 3- and Sb species removal from aqueous solutions and also compares other pollutants such as nitrate, sulphate, azodyes and cefazoline using the above adsorbents. The paper reports several synthesis routes, by which naturally available minerals or even waste products (furnace slag), occur in both cooperating countries in vast quantities and have been combined with specific biogenic components (like surfactant, alginate and xanthan gum) in order to prepare novel functional gradient adsorbents suitable for economically and ecologically viable water decontamination. Additionally, Fe-modified zeolite and the German commercial product GEH as well as the Czech Nanofer 25S in the form of stabilized aqueous suspension of Fe(0) were used in the experiments to compare the adsorption efficiency of the above materials.