Preparation and kinetic analysis of Li4SiO4 sorbents with different silicon sources for high temperature CO2 capture

Abstract

Using diatomite and analytical pure SiO 2 as silicon sources, Li 4 SiO 4 sorbents for high temperature CO 2 capture were prepared through solid-state reaction method. Phase composition was analyzed by X-ray diffraction, and the CO 2 absorption capacity and absorptoin-desorption performance were studied by the simultaneous thermal thermogravimetric analyzer (TG-DSC). The results showed that silicon source had an important influence on CO 2 absorption properties. The kinetic parameters for the chemisorption and diffusion processes were obtained by the isothermal study for different silicon sources. The results showed that the activation energies for these two processes were estimated to be 105.427 and 35.928 kJ/mol for the sample with analytical pure SiO 2 (AS). While for the sample with diatomite (DS), the activation energies for these two processes were estimated to be 78.500 and 20.439 kJ/mol, respectively. The increasing CO 2 concentration in the atmosphere due to fossil fuel burning has been considered as a major contributor to the global warming. So the separation, recovery and storage/utilization of CO 2 have attracted considerable attention in recent years. CO 2 can be removed from flue gas and waste gas streams by various methods such as membrane separation, wet absorption, and dry absorption [1][2][3][4]. However, these methods need to consume a lot of energy. Hence, the materials with high CO 2 capture capacity at high temperature are desirable. In recent years, the development of regenerable sorbents for high temperature CO 2 capture has received increasing attention [5][6][7]. Compared with other sorbents, Li 4 SiO 4 has the better CO 2 absorption properties over a wide range of temperature and CO 2 concentration [8,9]. In order to study the absorption mechanism of Li 4 SiO 4 materials, some researchers made some kinetic study about Li 4 SiO 4 materials [10]. However, kinetic study about different silicon sources has not been reported.In this paper, we firstly developed novel low-cost Li 4 SiO 4 sorbents for high temperature CO 2 capture using diatomite as silicon source. The effect of different silicon sources on the absorption capacity was investigated by studying their kinetic characteristics. In the following paper, DS and AS stand for diatomite and analytical pure SiO 2 , respectively.

Influence of the K‐, Na‐ and K‐Na‐carbonate additions during the CO2 chemisorption on lithium oxosilicate (Li8SiO6)

“…8 Among these materials, lithium silicates have been reported as good solid candidates for CO 2 sorbents in terms of large CO 2 sorption capacity and high operating temperatures. [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28] Recently, Durán-Muñoz et al 22 published that lithium oxosilicate (Li 8 SiO 6 ) is able to capture CO 2 over a wide temperature range with an experimental maximum capacity of 11.8 mmol CO 2 per gram of ceramic (theoretical 16.6 mmol/g). In addition, they reported that the Li 8 SiO 6 -CO 2 mechanism depends on the reaction temperature.…”

Solid‐Waste‐Derived Carbon Dioxide‐Capturing Materials

“…Later,W ang et al prepared Li 4 SiO 4 -based sorbents by using three kinds of silicas ources( citric acid treated RHA (CRHA), aerosil, and quartz)t oi nvestigate the impact on the microstructure and CO 2 capture performance. [181] The results showedt hat the sample derived from diatomite displayed a faster sorptionr ate and higher sorptionc apacity than those derived from pure SiO 2 as as ilicon source under the same conditions. [181] The results showedt hat the sample derived from diatomite displayed a faster sorptionr ate and higher sorptionc apacity than those derived from pure SiO 2 as as ilicon source under the same conditions.…”

“…[180] As ar esult, it was found that CRHA-Li 4 SiO 4 had ah igherC O 2 sorption capacity (6.92 mmol g À1 at 650 8C), faster kinetic reaction, and better cycling stability.A lso, its sorptionc apacity only decreased by 2.1 wt %f rom the 1st to the 15th cycle. [181] The results showedt hat the sample derived from diatomite displayed a faster sorptionr ate and higher sorptionc apacity than those derived from pure SiO 2 as as ilicon source under the same conditions. The maximum sorptionv alue of diatomite-derived Li 4 SiO 4 was 6.5 mmol g À1 .I na ddition, thanks to the presence of aluminum and other elements, lower activation energies were required by the diatomite-derived Li 4 SiO 4 for chemisorption and diffusion processes.…”

Progress in hydrotalcite like compounds and metal-based oxides for CO2 capture: a review

“…For instance, Li 4 SiO 4 obtained from diatomite shows superior absorption properties in comparison with Li 4 SiO 4 obtained from analytical grade, pure SiO 2 due to larger specific surface area and more uniform microstructure (Shan et al, 2013b;Yun et al, 2012). OlivaresMarin et al (2010b) reported that K-doped Li 4 SiO 4 obtained by using fly ash as source of SiO 2 exhibited a capacity of 101 mg g À1 under optimum conditions (at 600 C with 40 mol% K 2 CO 3 ).…”