Effects of Inherent/Enhanced Solid Acidity and Morphology of Diatomite Templates on the Synthesis and Porosity of Hierarchically Porous Carbon

Abstract

The inherent or enhanced solid acidity of raw or activated diatomite is found to have significant effects on the synthesis of hierarchically porous diatomite-templated carbon with high surface area and special porous structure. The solid acidity makes raw/activated diatomite a catalyst for the generation of porous carbon, and the porous parameters of the carbon products are strongly dependent on the solid acidity of diatomite templates. The morphology of diatomite also dramatically affects the textural structure of porous carbon. Two types of macroporous structures in the carbon product, the partially solid pillars and the ordered hollow tubes, derive from the replication of the central and the edge pores of diatom shell, respectively. The hierarchically porous carbon shows good capability for the adsorption of solvent naphtha and H(2), enabling potential applications in adsorption and gas storage.

Facile preparation of hierarchically porous carbon using diatomite as both template and catalyst and methylene blue adsorption of carbon products

“…The dominant diatoms of Dt(JL) and Dt(SD) are the genus Coscinodiscus Ehrenberg (Centrales) and Synedra Ehrenberg (Pennales), respectively. The chemical composition (wt%) of Dt(JL) was determined as follows: SiO 2 Three derivates of Dt(JL) were prepared by thermal and acid treatment [18]. Thermal treatment was performed in a programmed temperature-controlled muffle oven at 650°C for 3 h, and the obtained sample was denoted Dt(JL)/T.…”

“…In addition, investigation into the adsorption properties of the diatomite-templated carbons is very necessary for the related uses. However, these mentioned studies have not been sufficiently conducted, to the best of our knowledge [18].…”

Possible mechanism of structural incorporation of Al into diatomite during the deposition process I. Via a condensation reaction of hydroxyl groups

“…Diatomite is primarily composed of amorphous hydrated silica (SiO 2 ÁnH 2 O), which is categorized as non-crystalline Opal-A, according to the mineralogical classification [3,4]. Diatomite is easily obtained at very low cost and has many unique physical and chemical characteristics, enabling their wide uses in a variety of applications for high-performance technologies; thus and widely utilized [5][6][7][8]2,[9][10][11][12].…”

“…For example, the size of the nano-silica balls, which are the basic components of the diatom shell [28,29,2], most likely changes with the presence of Al in their framework because of the different sizes of Al and Si. In addition, the surface charge and solid acidity vary before and after Al incorporation into the structure [1,9]. However, the effect of Al incorporation on the structure and surface properties has not been investigated.…”

In situ hydrothermal synthesis of a novel hierarchically porous TS-1/modified-diatomite composite for methylene blue (MB) removal by the synergistic effect of adsorption and photocatalysis

“…Diatomite, which is also known as diatomaceous earth or kieselgur, is a fossil assemblage of diatom shells consisting of amorphous hydrated silica (SiO 2 ÁnH 2 O) and classified as opal-A in mineralogy. It is characterized by a macroporous structure, with pore sizes ranging from nanometers to micrometers [38][39][40]. As a fine-grained, low-density biogenetic sediment that is non-toxic and readily available in ton quantities at low cost, diatomite has been studied to evaluate its feasibility as a support for TS-1 nanoparticle coating.…”