Solidification mechanism of allophane by hydrothermal reaction

Characterization of Allophane from Gamalama Volcanic Soil, North Maluku, Indonesia

“…The OH vibrations of water molecules those are still trapped within the framework of allophane is indicated by absorption at 1635 cm -1 [9]. Vibration at 1033,85 and 586 cm -1 , respectively is an absorption for the Si-O-Al and Si-OAl in octahedral framework [10][11][12]. Absorption peak at 470,63 cm -1 which is absence in volcanic ash-soil, indicated peculiar wall structure of allophane ((HO) Si (OAL)3) [13].…”

“…3b. Maeda et al [12] succesfully isolated allophane from pumice bed in Kanuma, obtained from Otsuka collection. The SEM micrograph of it, showed irregular spherule form with diameter about 300 nm.…”

Experimental study of radon production and transport in an analogue for the Martian regolith

“…Allophane is an aggregate of hollow spherical particles with an outer diameter of 3.5-5.5 nm and wall thickness of 0.7-1.0 nm (Brigatti et al, 2006). The pore size measured by nitrogen adsorption on allophane samples was attributed to the space between the allophane aggregates (Maeda et al, 2009). These authors also found a peak at $4 nm by the BJH method.…”

Control of Deposits and Porous Properties of Hydrothermally Solidified Materials Using Clays

“…Recently, we succeeded in preparing mesoporous solidified materials derived from powder compacts containing kaolinite [2SiO 2 ·Al 2 O 3 ·2H 2 O] or metakaolinite [2SiO 2 ·Al 2 O 3 ] using hydrothermal treatment (hereinafter referred to as “treatment”) 10,11 . It was reported that the filling of pores between the particles in a powder compacts by the formation of deposits helps improve material strength after the hydrothermal process 12,13 . It was also suggested that the space associated with each fine‐sized deposit caused the formation of mesopores 14 .…”

“…10,11 It was reported that the filling of pores between the particles in a powder compacts by the formation of deposits helps improve material strength after the hydrothermal process. 12,13 It was also suggested that the space associated with each fine-sized deposit caused the formation of mesopores. 14 The amount and shape of the deposits in the solidified material is considered to play an important role in the porous structure of the materials.…”