“…As previously described, an increase in the specific surface and a decrease in the pore diameter are intrinsic in the case of PG 8B-b, which is related to the change of the packing of the secondary silica in the presence of ammonium chloride [10]. In addition, the relative increase in the content of the hydroxyl groups (a significant growth of the BAC-to-LBC ratio) is intrinsic in the specimen of PG 8B-с modified with the heteropolymolybdate ion [SiMo 12 O 40 ] 8via the additional treatment of PG 8B with the ammonium molybdate solution [11], which can be related to the ability of the Mo atoms to coordinate several acidic OH groups on the surface [12]. In addition, it was determined that the release of secondary silica from the pores along with the recondesation processes, which resulted in the increase in the pore diameter, was determined under the specified conditions of the treatment of PG [11].…”