Metal-Free Modified Boron Nitride for Enhanced CO2 Capture

Porous boron nitride is a new class of solid adsorbent with applications in CO2 capture. In order to further enhance the adsorption capacities of materials, new strategies such as porosity tuning, element doping and surface modification have been taken into account. In this work, metal-free modification of porous boron nitride (BN) has been prepared by a structure directing agent via simple heat treatment under N2 flow. We have demonstrated that textural properties of BN play a pivotal role in CO2 adsorption behavior. Therefore, addition of a triblock copolymer surfactant (P123) has been adopted to improve the pore ordering and textural properties of porous BN and its influence on the morphological and structural properties of pristine BN has been characterized. The obtained BN-P123 exhibits a high surface area of 476 m2/g, a large pore volume of 0.83 cm3/g with an abundance of micropores. More importantly, after modification with P123 copolymer, the capacity of pure CO2 on porous BN has improved by about 34.5% compared to pristine BN (2.69 mmol/g for BN-P123 vs. 2.00 mmol/g for pristine BN under ambient condition). The unique characteristics of boron nitride opens up new routes for designing porous BN, which could be employed for optimizing CO2 adsorption.

Surfactant Effect on the Synthesis of Mesoporous TiO2-SiO2 Coatings Using Sol-Gel Technology

The aim of the research was to develop the area of mesoporous thin films of a binary TiO2–SiO2 system. Sol was synthesized from tetraethylorthosilicate as the silica source and titanium isopropoxide solution as the TiO2 source, while triblock copolymer surfactant (Pluronic F 127 (10% solution in water, (P))) was used as the mesostructure-directing agent. In this paper we present sol-gel obtained TiO2–SiO2 with a mesoporous structure. The effects of added titanium on the mesostructure and on the porosity are presented and discussed. Four different molar percentage ratios of Ti: Si were used for the synthesis of mixed TiO2–SiO2 mesoporous thin films on glass substrate. The mesoporous structure of thin films was characterized by X-ray diffraction (XRD) patterns, atomic force microscopy (AFM), scanning electron microscopy (SEM) and the water contact angle. These mesoporous TiO2–SiO2 thin films could have many potential applications in many areas such as separation membranes, catalysis, optics, and self-cleaning surfaces.

Dummy molecularly imprinted mesoporous silicates for selective adsorption of 2-naphthol

Dummy molecularly imprinted mesoporous silicates (MIMS-2) were made by co-condensation of tetraethyl orthosilicate (TEOS) with precursors of bi-functional mimic of 2-naphthol, 2,7-dihydroxynaphthalene, around triblock copolymer surfactant Pluronic (P123) micelles. The bi-functional template was linked to two functional monomers through thermally cleavable covalent bonds to generate imprint precursor. This provides the possibility of incorporating the target into the cross-linked mesoporous silicate matrix in the non-ionic surfactant templated sol-gel process. P123 was eluted by ethanol extraction and template molecules were removed by refluxing the materials in a mixture of dimethyl sulfoxide (DMSO) and water. MIMS-1 was prepared similarly except that 2-naphthol was used as template instead of 2,7-dihydroxynaphthalene. Solid phase extraction studies showed that MIMS-2 exhibited good retention and selectivity for 2-naphthol among its structural analogues. The mono-functional molecule 2-naphthol was unable to be incorporated into the silica matrix of mesoporous material by the identical method, and the resulting material MIMS-1 exhibits poor selectivity to the template analogues.