*2.2. Chemicals*

Sodium metasilicate (Na2SiO3.9H2O, 95%, Merk KGaA, Darmstadt, Germany), cetyl trimethyl ammonium bromide (CTAB) (C19H42BrN, 98%, Loba Chemie Pvt. Ltd., Boisar, India), (HCl) (37%, Merk KGaA, Darmstadt, Germany), ethylene diamine tetra acetic acid (EDTA, Merk KGaA, Darmstadt, Germany), dihydrate, (C10H14N2Na2O8.2H2O, 99.5%, J.T. Baker, Phillipsburg, NJ, USA), silver nitrate (AgNO3, Merk KGaA, Darmstadt, Germany), and sodium chloride (NaCl, Merk KGaA, Darmstadt, Germany) were used in pure forms.
