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Low-Cost Microwave-Assisted Partial Pseudomorphic Transformation of Biogenic Silica

This work introduces a cost and time efficient procedure to specifically increase
mesopore volume and specific surface area of biogenic silica (specific surface area:
147 m2 g−1 and mesopore volume: 0.23 cm3 g−1) to make it suitable for applications
in adsorption or as catalyst support. The target values were a specific surface
area of ∼500 m2 g−1 and a mesopore volume of ∼0.40–0.50 cm3 g−1 as these
values are industrially relevant and are reached by potential concurring products such
as precipitated silica, silica gel, and fumed silica. The applied process of partial
pseudomorphic transformation was carried out as a single reaction step in a microwave
reactor instead of commonly used convective heating. In addition, the conventionally
used surfactant cetyltrimethylammonium bromide (CTABr) was substituted by the
low-cost surfactant (Arquad® 16-29, cetyltrimethylammonium chloride (CTACl) aqueous
solution). The influence of microwave heating, type of surfactant as well as the
concentration of NaOH and CTACl on the textural and structural properties of the
modified biogenic silica was investigated using nitrogen adsorption as well as scanning
and transmission electron microscopy. The results show that the textural parameters of
the modified biogenic silica can be exactly controlled by the amount of NaOH in the
reaction solution. By variation of the NaOH concentration, specific surface areas in the
range of 215–1,001m2 g−1 andmesopore volumes of 0.25–0.56 cm3 g−1 were achieved
after reaction at 393 K for 10min. The presented microwave route using the low-cost
surfactant solution decreases the reaction time by 99% and as shown in an example for
German prices, lowers the costs for the surfactant by 76–99%.

Identiferoai:union.ndltd.org:DRESDEN/oai:qucosa:de:qucosa:84524
Date03 April 2023
CreatorsSchneider, Denise, Kircheis, Ralf, Wassersleben, Susan, Einicke, Wolf-Dietrich, Gläser, Roger, Enke, Dirk
PublisherFrontiers Research Foundation
Source SetsHochschulschriftenserver (HSSS) der SLUB Dresden
LanguageEnglish
Detected LanguageEnglish
Typeinfo:eu-repo/semantics/publishedVersion, doc-type:article, info:eu-repo/semantics/article, doc-type:Text
Rightsinfo:eu-repo/semantics/openAccess
Relation2296-2646, 575

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