Increased Protonation of a Mesopore Surface in a Porous Clay Nanoheterostructure

Abstract

Embedding functionalized mesopores in silica materials is a straightforward approach for the design of adsorption materials suitable for volatile compounds such as acetaldehyde molecules. In this study, mesopores with protonated interior surfaces for porous clay nanoheterostructures (PCHs) originating from cost-effective and eco-friendly smectites were synthesized. The textural properties of both micro-and mesopores in the PCHs were analyzed by N 2 gas adsorption/desorption at −196 °C. Their chemical information was complemented by open-space analyses using positronium. The protonated mesopore surfaces enhanced the adsorption performance of acetaldehyde molecules through hydrogen bonds despite the reduction in mesoporosity. An approach to the tunability of protonation on the mesopore surfaces in PCHs is presented, focusing on the layer charge of base smectites caused by a few compositional percentage modifications.

Shrinkage Dynamics of Organic Template Substances with Long Alkyl Chains toward Porous Material Design

“…For comparison, the values of S BET , d p , and V micro previously obtained for base saponite are given as well. 5 The value of d p for the base saponite is approximately 3.0 nm, attributed to the nonrigid slit-like pores, as suggested by the type-II isotherms (H3 type) and our former Ps lifetime spectroscopy. 41−43 PCH 323K and PCH 423K exhibit d p of ∼2.7 and ∼2.6 nm, respectively.…”

“…Figure a shows N 2 adsorption/desorption isotherms observed for PCHs synthesized from the saponite-HDTMA + agglomerates prepared at 323 and 423 K, which is already defined as PCH 323K and PCH 423K (see the Experimental Section). The data of base saponite measured in our previous work are presented as well for comparison . The adsorption isotherm of base saponite is classified as type II characteristic for nonporous and macroporous adsorbents according to the International Union of Pure and Applied Chemistry (IUPAC) classification.…”

“…The data of base saponite measured in our previous work are presented as well for comparison. 5 The adsorption isotherm of base saponite is classified as type II characteristic for nonporous and macroporous adsorbents according to the International Union of Pure and Applied Chemistry (IUPAC) classification. The hysteresis loop in the relative pressure P/P 0 range from 0.4 to 0.9 is associated with the H3 type, corresponding to nonrigid aggregates of plate-like particles as clay minerals.…”

“…11 Optimization of the second process, pillaring by templates between nanosheets, could be straightforward for raising the productivity of mesopores as well as their sizes since the nanometer-sized templates are removed to be mesopore sites. The pillaring effect and relevant enhancement of mesoporosity together with mesopore sizes have been thus studied focusing on the layer charges of base clay, 5 the chain length of surfactant, 12 the content of base clay, 13 and so on.…”

Synthesis and Adsorbent Properties of Silica-Titanate Nanoarchitectures Produced by Unrolling Titanate Tubular Sheets

“…On the other hand, the higher N 2 adsorption at p / p 0 < 0.4 in SiO 2 -TNT isotherm reveals a strong adsorbent–adsorbate interaction in the case of SiO 2 -TNT resulting from its more open structure than the Na-TNT initial nanotubes. In addition, the gradient adsorption in the p / p 0 region of 0.12–0.4 in SiO 2 -TNT isotherm indicates the formation of a new mesoporous structure, which is similar to other layered-type mesoporous materials (e.g., PCHs and pillared zeolites). − …”