- Email: [email protected]
Can Natural Muscovite be Expanded?
Colloids and Surfaces A: Physicochem. Eng. Aspects 471 (2015) 19–25
Contents lists available at ScienceDirect
Colloids and Surfaces A: Physicochemical and Engineering Aspects journal homepage: www.elsevier.com/locate/colsurfa
Can Natural Muscovite be Expanded? Feifei Jia a,b , Jing Su a , Shaoxian Song a,∗ a b
School of Resources and Environmental Engineering, Wuhan University of Technology, Luoshi Road 122, Wuhan, Hubei, 430070, China Instituto de Metalurgia, Universidad Autonoma de San Luis Potosi, Av. Sierra Leona 550, San Luis Potosi, C.P. 78210, Mexico
h i g h l i g h t s
g r a p h i c a l
• Natural muscovite was expanded by
The expansion of natural muscovite could be realized through calcination, K+ /Li+ ion exchange and Li+ /OTA+ exchange.
thermal treatment and ion exchange. • The basal spacing of muscovite was increased around 7 times after treatments. • Calcination led the interlamellar K+ exchangeable.
a r t i c l e
i n f o
Article history: Received 24 November 2014 Received in revised form 30 January 2015 Accepted 4 February 2015 Available online 12 February 2015 Keywords: muscovite expansion calcination ion exchange
a b s t r a c t In this work the expansion of natural muscovite has been made through the treatments of calcination and ion exchange. The experimental results have demonstrated that the gallery of muscovite could be expanded from 0.32 nm to 2.25 nm with the treatments. The calcination was to weaken the bond or attraction of the layers to interlamellar K+ and to move slightly the O atoms in dehydroxylation. The Li+ /K+ and OTA+ /Li+ exchanges led to the expansion of muscovite, which might be due to the low layer charge of muscovite after Li+ /K+ exchange and the long chain of OTA+ , respectively. © 2015 Elsevier B.V. All rights reserved.
1. Introduction Natural 2 M1 muscovite, with ideal composition of KAl2 (Si3 AlO10 )(OH)2 , is a 2:1 phyllosilicate silicate mineral. Each layer is composed of two tetrahedral sheets and one dioctahedral sheet, sandwiched between two tetrahedral sheets. In tetrahedral sheets, silicon atoms randomly occupy approximate 75% of the tetrahedral sites, and aluminum atoms occupy the remaining sites. In dioctahedral sheets, 2/3 octahedral sites are occupied by aluminum atoms, and the rest sites are vacant [1].
∗ Corresponding author. Tel.: +86 027 87212127. E-mail address: [email protected] (S. Song). http://dx.doi.org/10.1016/j.colsurfa.2015.02.009 0927-7757/© 2015 Elsevier B.V. All rights reserved.
a b s t r a c t
It is common that Si4+ and Al3+ are replaced by isomorphic low charge cations, accordingly the host layers are negatively charged and alkali ion, mainly K+ , is attracted in the interlayer to counterbalance the charge of the layers [2]. Muscovite layers have severe charge deficiency, therefore unlike silicates with moderate deficiency, e.g. smectites, the interlamellar cations in muscovite are no expandable, and can not be exchanged easily, or no charge defective silicates, e.g. talc, strong Coulombic interaction couples the adjacent layers beside van der Waals forces [3,4]. Smectite and vermiculite are natural expandable silicate minerals in water due to the hydration of their interlamellar cations. The water absorbency of Na+ -montmorillonite reached to 638 g/g, resulting in a significant swell [5]. In the case of vermiculite, the water in the galleries will turn into steam under microwave
20
F. Jia et al. / Colloids and Surfaces A: Physicochem. Eng. Aspects 471 (2015) 19–25
Fig. 1. SEM image of the muscovite sample.
heating, forcing the layers apart in an accordion-like expansion [6]. If a silicate mineral has high CEC, polymer intercalation into galleries is a widely used method to pillar the interlayer due to the long chains of the polymers. The interlayer spacing of silicate minerals could be expanded to 2-3 nm through the treatments [7–10]. Lee et al. [11] found that the d-spacing of montmorillonite was expanded to 5.8 nm after intercalated with poly(oxypropylene)amine. Is it possible to expand muscovite as smectite and vermiculite do through some thermal or chemical treatments, since muscovite has the similar molecular structure? To answer this question, this work attempted to open the gallery and to increase the basal spacing of natural muscovite through thermal treatment and ion exchange. The thermal treatment was to weaken the bond or attraction force between K+ and the layers, and the ion exchange with large-chain cations was to pillar the interlayer and then to increase the basal spacing. Expanded muscovite might have considerable potential applications, such as adsorption and filling industries. It might be the first step to prepare nanoscale laminated muscovite. Polymers, nanometer metallic oxide and metal ions could intercalate into muscovite galleries to form specialized nanocomposites. Also, it might be used as adsorbents for oil, toxic chemicals and organic pollutants, drug carriers in
pharmaceutical field, rheological control agents, reinforcing fillers, etc.
2. Experimental methods 2.1. Materials The natural muscovite powder sample used in this work was received from Liaoning science Co., Ltd, China. The X-ray diffraction (XRD) study showed that the main composition of the sample was muscovite. The chemical formula obtained from inductively coupled plasma emission spectroscopic (ICP) data and thermogravimetric analysis was (K1.02 Na0.06 )(Ca0.06 Mg0.03 Fe0.32 )(Si2.77 Al2.37 Sn0.022 Ti0.014 )O10 (OH)0.35 . The SEM image of the sample is given in Fig. 1. It shows that the muscovite is plate-like particle. The face dimension of most particles is less than 100 m (Fig. 1a) and the particles are compact from the edge (Fig. 1b). Fig. 2 illustrates the particle size distribution of the sample, showing that the mass median diameter (d50 ) was 21.7 m. Lithium nitrate (LiNO3 ) and trimethyloctadecylammonium chloride (OTAC) used in this work were from Sinopharm
100
Distribution (%)
80
60
40
20
0
0
20
40
60
Particle siz ze (um) Fig. 2. Cumulative particle size distribution of the muscovite sample.
80
F. Jia et al. / Colloids and Surfaces A: Physicochem. Eng. Aspects 471 (2015) 19–25
21
Fig. 3. Schematic representative of the expansion of natural muscovite.
Chemical Reagent Co., Ltd, China and were of analytical grade. Ultrapure Milli-Q water was used in all experiments.
1:1 ethanol/water mixture until no chloride was detected by adding 0.1 mol/l of AgNO3 . The powder was dried in a vacuum oven at 80 ◦ C for 24 hours, which was denoted as OTA-muscovite 700.
2.2. Methods 2.3. Measurements Fig. 3 schematically represents the process used in this study for the expansion of natural muscovite. It includes three steps, namely calcination, Li+ /K+ ion exchange and OTA+ /Li+ exchange. In the calcination, 5 g muscovite powder was first placed in a ceramic crucible, then into a Vulcan 3-550 muffle furnace (Addlestone, Surrey, UK), and heated from room temperature to 700 ◦ C at a rate of 20 ◦ C/min. Afterwards, the temperature in the furnace was kept constant for 5 h. The crucible then was cooled to room temperature in the furnace. The product from this calcination was named as muscovite 700. For the exchange of interlaminar K+ by Li+ , 5 g muscovite 700 was first mixed with 300 g LiNO3 and put in a ceramic crucible, followed by heating at 300 ◦ C in muffle furnace for 48 h. Then it was cooled to room temperature in the furnace. After that, the powder was mixed and washed with water, followed by filtration and drying at 80 ◦ C in a vacuum oven. The product was named as Li-muscovite 700. The exchange of interlaminar Li+ by OTA+ was realized in a saturated OTAC solution at 80 ◦ C. 150 ml solution and 1 g Limuscovite 700 were mixed and then stirred by a magnetic stirrer for 48 hours. After that, the mixture was filtered and washed with
A Joel JSM-6610 LV scanning electron microscope was used to observe the morphology and size of the muscovite and the OTAmuscovite 700. To prepare SEM samples, the powder sample was carefully stuck on pin-type mushroom specimen mounts, followed by coating with carbon film. The particle size of the sample was determined by using a Malvern Mastersizer 2000 particle size analyzer. The particle size given in this work was equivalent sphere diameter. A Mettler Toledo TGA/SDTA 851 thermogravimetric analyzer (TGA) was used to relate the weight loss and decomposition temperature. Before the measurement, muscovite was mixed and 10 g of sample was taken. The analysis was performed from room temperature to 1000 ◦ C in air with the temperature rising rate of 5 ◦ C/min. The elemental analysis of muscovite was performed using the PerkinElmer Optima4300DV inductively coupled plasma emission spectroscopic (ICP). XRD patterns were obtained with a Bruker D8 Advance X-Ray diffractometer with CuK␣ radiation. The diffraction patterns in the 2 range from 5o to 80o were collected with a step-scanning speed
101
100
Mass, %
99
98
97
96
95
0
200
400
600 o
Temperature, C Fig. 4. TGA pattern of the muscovite powder.
800
1000
22
F. Jia et al. / Colloids and Surfaces A: Physicochem. Eng. Aspects 471 (2015) 19–25
Fig. 5. XRD patterns of the muscovite before and after calcination in the range of 4-90o (a) and 7-10.5o (b).
of 10o /min. The small-angle diffraction patterns from 1o to 10o were collected using a step-scanning speed of 1o /min. Far-infrared (50-400 cm−1 ) and middle-infrared (4004000 cm−1 ) transmission spectra were collected with a Thermo Scientific Nicolet 6700 FT-IR spectrometer. 3. Results and discussions 3.1. Calcination Fig. 4 shows the TGA pattern of the muscovite in the temperature range of 25 to 1000 ◦ C, displaying a slight loss of mass at 600-770 ◦ C and an enormous loss after 770 ◦ C. It corresponds to the dehydroxylation [12] and decomposition of muscovite, respectively. In other words, muscovite did not decompose being calcined at 700 ◦ C. Fig. 5 illustrates the XRD patterns of the muscovite and the muscovite 700. It shows that the two XRD patterns were very similar, indicating that muscovite did not decompose at 700 ◦ C. This result
was in a good agreement with that from the TGA analysis. Moreover, it is shown in Fig. 5b that the peak moved leftward a little after calcination at 700 ◦ C. According to the Scherrer equation, the values of basal spacing (d) of muscovite before and after being calcinated were 0.99 nm and 1.01 nm, respectively. Even though the increase was only 0.02 nm, it indicated that the calcination at 700 ◦ C indeed opened the interlayer of the muscovite. The IR spectra of -OH groups in muscovite structure before and after being calcined at 700 ◦ C are given in Fig. 6. It shows that -OH absorption bands (3627, 2922 and 2852 cm−1 ) disappeared after being calcined. Combined with the XRD result, it could be concluded that dehydroxylation occurred in muscovite after the calcination. Fig. 7 shows the far-infrared spectra of muscovite before and after calcination. The K+ absorption band frequency shifted from 108 to 96 cm−1 after the calcination, suggesting a decrease of the specific interaction of muscovite layers to interlaminar K+ and an increase of the K+ exchangeability [13]. This is solidly in agreement with the previous work, which found that the attraction force of the layers to K+ in muscovite was weaker after dehydroxylation [14].
Fig. 6. Middle-infrared spectra of OH groups in muscovite structure before and after calcination.
F. Jia et al. / Colloids and Surfaces A: Physicochem. Eng. Aspects 471 (2015) 19–25
23
Fig. 7. Far-infrared spectra of interlaminar K in muscovite structure before and after calcination.
In addition, the O atom which results from the dehydroxylation process migrated into the vacant octahedral site of the structure, increasing the K-O distance [13]. Thus, it might be presumed that the dehydroxylation in the calcination of muscovite could weaken the attraction force of layers to K+ and thus facilitate the exchangeability of K+ , and also could slightly increase the basal spacing of muscovite interlayer. 3.2. Li+ /K+ exchange The XRD patterns of the muscovite 700 before and after the addition of LiNO3 are given in Fig. 8. It shows that there were three
d=1.21nm
006
*
Intensity, cps
new apparent peaks (marked by *) on the Li-muscovite 700, which appeared at the left shifts of the (002), (004), (008) peaks, respectively. In fact, slight left movement also occurred to peak (006) and (010), which was not clearly observed. The leftward movements of the peaks suggested the increase of the basal spacing of the muscovite. According to the Scherrer equation, the Li-muscovite 700 had the basal spacing of 1.21 nm, compared with that of 1.01 nm of the muscovite 700. It indicates that the Li+ /K+ exchange really opened the interlayers and increased the basal spacing. This result might because Li+ entered the lattice of muscovite and reduced the layer charge to a lower value, causing the interlamellar expansion [15]. It is worth mentioning that except for the left moving
002 004
*
1 006
d=1.01nm 002 004 20
010
* 008
Li-muscovite 700
008
010
Muscovite 700
40
60
2θ,
o
Fig. 8. XRD patterns of muscovite 700 before and after the addition of LiNO3 .
80
24
F. Jia et al. / Colloids and Surfaces A: Physicochem. Eng. Aspects 471 (2015) 19–25
Fig. 9. Infrared spectroscopy of muscovite and OTA-muscovite 700.
of the peaks, some remained in their original position after Li+ /K+ exchange, indicated that the removal of K+ was not complete after only once LiNO3 treatment. 3.3. OTA+ /Li+ exchange for muscovite expansion Fig. 9 illustrates the infrared spectroscopy of muscovite and OTA-muscovite 700. Three new absorption bands at 2918, 2850 and 1469 cm−1 were observed after the OTA+ /Li+ exchange. The bands at 2918 and 2850 cm−1 corresponded to CH2 asymmetric and symmetric stretching vibration modes of alkyl chain, respectively, while that at 1469 cm−1 was from methylene scissoring mode [16]. Clearly, OTA+ was detected on the muscovite after it substituted Li+
from Li-muscovite 700. In other words, the OTA+ /Li+ exchange on Li-muscovite 700 led to the formation of OTA-muscovite 700. The comparison of the XRD patterns of the Li-muscovite 700 and OTA-muscovite 700 was given in Fig. 10. It shows that the peaks moved leftward to lower angle region with the OTAC addition, suggesting an increase of the basal spacing. According to Scherrer equation, the basal spacing (d) was calculated from the 002 diffraction peak to be 2.92 nm for the OTA-muscovite 700. The OTA+ /Li+ exchange on Li-muscovite 700 greatly increased the basal spacing, from 1.21 nm to 2.92 nm. Because the thickness of the aluminosilicate layer is about 0.67 nm [17], the distance between the adjacent aluminosilicate layers of the muscovite increased 0.54 nm for the Li-muscovite 700 and 2.25 nm for the OTA-muscovite 700.
Intensity, cps
d=2.91nm (002)
(004) O OTA-muscovite 700 d=1.21nm (002)
Li-muscovite 700 7 2
3
4
5
2θ,
6
7
o
Fig. 10. Small-angle XRD diffraction patterns of Li-muscovite 700 and OTA-muscovite 700.
8
F. Jia et al. / Colloids and Surfaces A: Physicochem. Eng. Aspects 471 (2015) 19–25
25
attributed to the lower layer charge caused by the entering of Li+ into the lattice of muscovite. The OTA+ /Li+ exchange led the muscovite to expand greatly, resulting in the distance between the adjacent aluminosilicate layers of the muscovite increased from 0.32 nm to 2.25 nm. Acknowledgements This study was supported by the National Natural Science Foundation of China under the project No. 51474167. F. Jia also would like to thank the Consejo Nacional de Ciencia y Tecnología of México for offering her the scholarship under the grant No. 290733 during her Ph. D. studying. References
Fig. 11. SEM image of OTA-muscovite 700.
Obviously, the combination of thermal treatment and ion exchange could expand natural muscovite. Fig. 11 shows the SEM image of the edges of the OTA-muscovite 700. Loose framework can be observed, which was quite different from that of original muscovite as shown in Fig. 1b. This might be attributed to the expansion of the muscovite due to the increase of the basal spacing after the thermal treatment and ion exchange. 4. Conclusion The experimental results presented in this work have demonstrated that natural muscovite could be expanded through the treatments of calcination and ion exchange. The calcination only slightly opened the muscovite interlayer, about 0.02 nm, but improved the interlamellar K+ exchangeability and facilitated the following Li+ /K+ exchange. The Li+ /K+ exchange increased the basal spacing of muscovite from 0.99 nm to 1.21 nm, which might be
[1] D.A. Mckeown, M.I. Bell, E.S. Etz, Vibrational analysis of the dioctahedral mica: 2 M1 muscovite, Am. Mineral. 84 (1999) 1041–1048. [2] K. Tamura, S. Yokoyama, C.S. Pascua, H. Yamada, New age of polymer nanocomposites containing dispersed high-aspect-ratio silicate nanolayers, Mater. Chem. 20 (2008) 2242–2246. [3] M.A. Osman, U.W. Suter, Determination of the cation-exchange capacity of muscovite mica, J.Colloid Interface Sci. 224 (2000) 112–115. [4] M.A. Osman, C. Moor, W.R. Caseri, U.W. Suter, Alkali metals ion exchange on muscovite mica, J.Colloid Interface Sci. 209 (1999) 232–239. [5] Y. Zheng, A. Wang, Study on superabsorbent composite. XX. Effects of cation-exchanged montmorillonite on swelling properties of superabsorbent composite containing sodium humate, Polym. Compos. 30 (2009) 1138–1145. [6] O. Folorunso, C. Dodds, G. Dimitrakis, S. Kingman, Continuous energy efficient exfoliation of vermiculite through microwave heating, Int. J. Miner. Process. 114-117 (2012) 69–79. [7] F.A. Bottino, E. Fabbri, I.L. Fragala, G. Malandrino, A. Orestano, F. Pilati, A. Pollicino, Polystyrene-clay nanocomposites prepared with polymerizable imidazolium surfactants, Macromol. Rapid Commun. 24 (2003) 1079–1084. [8] J.W. Gilman, W.H. Awad, R.D. Davis, J. Shields Jr., R.H. Harris, C. Davis, A.B. Morgan, T.E. Sutto, J. Callahan, P.C. Trulove, H.C. De Long, Polymer/layered silicate nanocomposites from thermally stable trialkylimidazolium-treated montmorillonite, Chem. Mater. 14 (2002) 3776–3785. [9] A. Szabo, D. Gournis, M.A. Karakassides, D. Petridis, Clay-aminopropylsiloxane compositions, Chem. Mater. 10 (1998) 639–645. [10] Y. Hotta, K. Inukai, M. Taniguchi, M. Nakata, A. Yamagishi, A clay self assembled on a gold surface as studied by atomic force nicroscopy and electrochemistry, Langmuir 13 (1997) 6697–6703. [11] R. Lee, J. Lin, W. Cheng, Self-aligned nematic crystallization of poly(oxypropylene)amine intercalated silicates, Mater. Sci. Eng. C 28 (2008) 1352–1355. [12] S. Guggenheim, Y. Chang, A.F. Koster van Groos, Muscovite dehydroxylation: high-temperature studies, Am. Mineral. 72 (1987) 537–550. [13] R. Prost, V. Laperche, Far-infrared study of potassium in micas, Clays Clay Miner. 38 (1990) 351–355. [14] J.M. Rousseaux, Y., Nathan, L.A., Vielvoye, A. Herbillon, The vermiculitization of trioctahedral micas. II. Correlations between the K level and crystallographic parameters, in Proc. Int. Clay Conf., J.M. Serratosa (ed.), Div. Ciencias C.S.I.C., Madrid, 1972, 449-456. [15] Joe L. White, Layer charge and interlamellar expansion in a muscovite, Journal Paper No. 994, Purdue University Agricultural Experiment Station, Lafayette, Indiana. [16] R.A. MacPhail, H.L. Strauss, R.G. Snyder, Carbon-hydrogen stretching modes and the structure of n-alkyl chains. 2. long, all-trans chains, J. Phys. Chem. 88 (1984) 334–341. [17] X. Yu, The preparation and characterization of cetyltrimethylammonium intercalated muscovite, Microporous Mesoporous Mater. 98 (2007) 70–79.
Contents lists available at ScienceDirect
Colloids and Surfaces A: Physicochemical and Engineering Aspects journal homepage: www.elsevier.com/locate/colsurfa
Can Natural Muscovite be Expanded? Feifei Jia a,b , Jing Su a , Shaoxian Song a,∗ a b
School of Resources and Environmental Engineering, Wuhan University of Technology, Luoshi Road 122, Wuhan, Hubei, 430070, China Instituto de Metalurgia, Universidad Autonoma de San Luis Potosi, Av. Sierra Leona 550, San Luis Potosi, C.P. 78210, Mexico
h i g h l i g h t s
g r a p h i c a l
• Natural muscovite was expanded by
The expansion of natural muscovite could be realized through calcination, K+ /Li+ ion exchange and Li+ /OTA+ exchange.
thermal treatment and ion exchange. • The basal spacing of muscovite was increased around 7 times after treatments. • Calcination led the interlamellar K+ exchangeable.
a r t i c l e
i n f o
Article history: Received 24 November 2014 Received in revised form 30 January 2015 Accepted 4 February 2015 Available online 12 February 2015 Keywords: muscovite expansion calcination ion exchange
a b s t r a c t In this work the expansion of natural muscovite has been made through the treatments of calcination and ion exchange. The experimental results have demonstrated that the gallery of muscovite could be expanded from 0.32 nm to 2.25 nm with the treatments. The calcination was to weaken the bond or attraction of the layers to interlamellar K+ and to move slightly the O atoms in dehydroxylation. The Li+ /K+ and OTA+ /Li+ exchanges led to the expansion of muscovite, which might be due to the low layer charge of muscovite after Li+ /K+ exchange and the long chain of OTA+ , respectively. © 2015 Elsevier B.V. All rights reserved.
1. Introduction Natural 2 M1 muscovite, with ideal composition of KAl2 (Si3 AlO10 )(OH)2 , is a 2:1 phyllosilicate silicate mineral. Each layer is composed of two tetrahedral sheets and one dioctahedral sheet, sandwiched between two tetrahedral sheets. In tetrahedral sheets, silicon atoms randomly occupy approximate 75% of the tetrahedral sites, and aluminum atoms occupy the remaining sites. In dioctahedral sheets, 2/3 octahedral sites are occupied by aluminum atoms, and the rest sites are vacant [1].
∗ Corresponding author. Tel.: +86 027 87212127. E-mail address: [email protected] (S. Song). http://dx.doi.org/10.1016/j.colsurfa.2015.02.009 0927-7757/© 2015 Elsevier B.V. All rights reserved.
a b s t r a c t
It is common that Si4+ and Al3+ are replaced by isomorphic low charge cations, accordingly the host layers are negatively charged and alkali ion, mainly K+ , is attracted in the interlayer to counterbalance the charge of the layers [2]. Muscovite layers have severe charge deficiency, therefore unlike silicates with moderate deficiency, e.g. smectites, the interlamellar cations in muscovite are no expandable, and can not be exchanged easily, or no charge defective silicates, e.g. talc, strong Coulombic interaction couples the adjacent layers beside van der Waals forces [3,4]. Smectite and vermiculite are natural expandable silicate minerals in water due to the hydration of their interlamellar cations. The water absorbency of Na+ -montmorillonite reached to 638 g/g, resulting in a significant swell [5]. In the case of vermiculite, the water in the galleries will turn into steam under microwave
20
F. Jia et al. / Colloids and Surfaces A: Physicochem. Eng. Aspects 471 (2015) 19–25
Fig. 1. SEM image of the muscovite sample.
heating, forcing the layers apart in an accordion-like expansion [6]. If a silicate mineral has high CEC, polymer intercalation into galleries is a widely used method to pillar the interlayer due to the long chains of the polymers. The interlayer spacing of silicate minerals could be expanded to 2-3 nm through the treatments [7–10]. Lee et al. [11] found that the d-spacing of montmorillonite was expanded to 5.8 nm after intercalated with poly(oxypropylene)amine. Is it possible to expand muscovite as smectite and vermiculite do through some thermal or chemical treatments, since muscovite has the similar molecular structure? To answer this question, this work attempted to open the gallery and to increase the basal spacing of natural muscovite through thermal treatment and ion exchange. The thermal treatment was to weaken the bond or attraction force between K+ and the layers, and the ion exchange with large-chain cations was to pillar the interlayer and then to increase the basal spacing. Expanded muscovite might have considerable potential applications, such as adsorption and filling industries. It might be the first step to prepare nanoscale laminated muscovite. Polymers, nanometer metallic oxide and metal ions could intercalate into muscovite galleries to form specialized nanocomposites. Also, it might be used as adsorbents for oil, toxic chemicals and organic pollutants, drug carriers in
pharmaceutical field, rheological control agents, reinforcing fillers, etc.
2. Experimental methods 2.1. Materials The natural muscovite powder sample used in this work was received from Liaoning science Co., Ltd, China. The X-ray diffraction (XRD) study showed that the main composition of the sample was muscovite. The chemical formula obtained from inductively coupled plasma emission spectroscopic (ICP) data and thermogravimetric analysis was (K1.02 Na0.06 )(Ca0.06 Mg0.03 Fe0.32 )(Si2.77 Al2.37 Sn0.022 Ti0.014 )O10 (OH)0.35 . The SEM image of the sample is given in Fig. 1. It shows that the muscovite is plate-like particle. The face dimension of most particles is less than 100 m (Fig. 1a) and the particles are compact from the edge (Fig. 1b). Fig. 2 illustrates the particle size distribution of the sample, showing that the mass median diameter (d50 ) was 21.7 m. Lithium nitrate (LiNO3 ) and trimethyloctadecylammonium chloride (OTAC) used in this work were from Sinopharm
100
Distribution (%)
80
60
40
20
0
0
20
40
60
Particle siz ze (um) Fig. 2. Cumulative particle size distribution of the muscovite sample.
80
F. Jia et al. / Colloids and Surfaces A: Physicochem. Eng. Aspects 471 (2015) 19–25
21
Fig. 3. Schematic representative of the expansion of natural muscovite.
Chemical Reagent Co., Ltd, China and were of analytical grade. Ultrapure Milli-Q water was used in all experiments.
1:1 ethanol/water mixture until no chloride was detected by adding 0.1 mol/l of AgNO3 . The powder was dried in a vacuum oven at 80 ◦ C for 24 hours, which was denoted as OTA-muscovite 700.
2.2. Methods 2.3. Measurements Fig. 3 schematically represents the process used in this study for the expansion of natural muscovite. It includes three steps, namely calcination, Li+ /K+ ion exchange and OTA+ /Li+ exchange. In the calcination, 5 g muscovite powder was first placed in a ceramic crucible, then into a Vulcan 3-550 muffle furnace (Addlestone, Surrey, UK), and heated from room temperature to 700 ◦ C at a rate of 20 ◦ C/min. Afterwards, the temperature in the furnace was kept constant for 5 h. The crucible then was cooled to room temperature in the furnace. The product from this calcination was named as muscovite 700. For the exchange of interlaminar K+ by Li+ , 5 g muscovite 700 was first mixed with 300 g LiNO3 and put in a ceramic crucible, followed by heating at 300 ◦ C in muffle furnace for 48 h. Then it was cooled to room temperature in the furnace. After that, the powder was mixed and washed with water, followed by filtration and drying at 80 ◦ C in a vacuum oven. The product was named as Li-muscovite 700. The exchange of interlaminar Li+ by OTA+ was realized in a saturated OTAC solution at 80 ◦ C. 150 ml solution and 1 g Limuscovite 700 were mixed and then stirred by a magnetic stirrer for 48 hours. After that, the mixture was filtered and washed with
A Joel JSM-6610 LV scanning electron microscope was used to observe the morphology and size of the muscovite and the OTAmuscovite 700. To prepare SEM samples, the powder sample was carefully stuck on pin-type mushroom specimen mounts, followed by coating with carbon film. The particle size of the sample was determined by using a Malvern Mastersizer 2000 particle size analyzer. The particle size given in this work was equivalent sphere diameter. A Mettler Toledo TGA/SDTA 851 thermogravimetric analyzer (TGA) was used to relate the weight loss and decomposition temperature. Before the measurement, muscovite was mixed and 10 g of sample was taken. The analysis was performed from room temperature to 1000 ◦ C in air with the temperature rising rate of 5 ◦ C/min. The elemental analysis of muscovite was performed using the PerkinElmer Optima4300DV inductively coupled plasma emission spectroscopic (ICP). XRD patterns were obtained with a Bruker D8 Advance X-Ray diffractometer with CuK␣ radiation. The diffraction patterns in the 2 range from 5o to 80o were collected with a step-scanning speed
101
100
Mass, %
99
98
97
96
95
0
200
400
600 o
Temperature, C Fig. 4. TGA pattern of the muscovite powder.
800
1000
22
F. Jia et al. / Colloids and Surfaces A: Physicochem. Eng. Aspects 471 (2015) 19–25
Fig. 5. XRD patterns of the muscovite before and after calcination in the range of 4-90o (a) and 7-10.5o (b).
of 10o /min. The small-angle diffraction patterns from 1o to 10o were collected using a step-scanning speed of 1o /min. Far-infrared (50-400 cm−1 ) and middle-infrared (4004000 cm−1 ) transmission spectra were collected with a Thermo Scientific Nicolet 6700 FT-IR spectrometer. 3. Results and discussions 3.1. Calcination Fig. 4 shows the TGA pattern of the muscovite in the temperature range of 25 to 1000 ◦ C, displaying a slight loss of mass at 600-770 ◦ C and an enormous loss after 770 ◦ C. It corresponds to the dehydroxylation [12] and decomposition of muscovite, respectively. In other words, muscovite did not decompose being calcined at 700 ◦ C. Fig. 5 illustrates the XRD patterns of the muscovite and the muscovite 700. It shows that the two XRD patterns were very similar, indicating that muscovite did not decompose at 700 ◦ C. This result
was in a good agreement with that from the TGA analysis. Moreover, it is shown in Fig. 5b that the peak moved leftward a little after calcination at 700 ◦ C. According to the Scherrer equation, the values of basal spacing (d) of muscovite before and after being calcinated were 0.99 nm and 1.01 nm, respectively. Even though the increase was only 0.02 nm, it indicated that the calcination at 700 ◦ C indeed opened the interlayer of the muscovite. The IR spectra of -OH groups in muscovite structure before and after being calcined at 700 ◦ C are given in Fig. 6. It shows that -OH absorption bands (3627, 2922 and 2852 cm−1 ) disappeared after being calcined. Combined with the XRD result, it could be concluded that dehydroxylation occurred in muscovite after the calcination. Fig. 7 shows the far-infrared spectra of muscovite before and after calcination. The K+ absorption band frequency shifted from 108 to 96 cm−1 after the calcination, suggesting a decrease of the specific interaction of muscovite layers to interlaminar K+ and an increase of the K+ exchangeability [13]. This is solidly in agreement with the previous work, which found that the attraction force of the layers to K+ in muscovite was weaker after dehydroxylation [14].
Fig. 6. Middle-infrared spectra of OH groups in muscovite structure before and after calcination.
F. Jia et al. / Colloids and Surfaces A: Physicochem. Eng. Aspects 471 (2015) 19–25
23
Fig. 7. Far-infrared spectra of interlaminar K in muscovite structure before and after calcination.
In addition, the O atom which results from the dehydroxylation process migrated into the vacant octahedral site of the structure, increasing the K-O distance [13]. Thus, it might be presumed that the dehydroxylation in the calcination of muscovite could weaken the attraction force of layers to K+ and thus facilitate the exchangeability of K+ , and also could slightly increase the basal spacing of muscovite interlayer. 3.2. Li+ /K+ exchange The XRD patterns of the muscovite 700 before and after the addition of LiNO3 are given in Fig. 8. It shows that there were three
d=1.21nm
006
*
Intensity, cps
new apparent peaks (marked by *) on the Li-muscovite 700, which appeared at the left shifts of the (002), (004), (008) peaks, respectively. In fact, slight left movement also occurred to peak (006) and (010), which was not clearly observed. The leftward movements of the peaks suggested the increase of the basal spacing of the muscovite. According to the Scherrer equation, the Li-muscovite 700 had the basal spacing of 1.21 nm, compared with that of 1.01 nm of the muscovite 700. It indicates that the Li+ /K+ exchange really opened the interlayers and increased the basal spacing. This result might because Li+ entered the lattice of muscovite and reduced the layer charge to a lower value, causing the interlamellar expansion [15]. It is worth mentioning that except for the left moving
002 004
*
1 006
d=1.01nm 002 004 20
010
* 008
Li-muscovite 700
008
010
Muscovite 700
40
60
2θ,
o
Fig. 8. XRD patterns of muscovite 700 before and after the addition of LiNO3 .
80
24
F. Jia et al. / Colloids and Surfaces A: Physicochem. Eng. Aspects 471 (2015) 19–25
Fig. 9. Infrared spectroscopy of muscovite and OTA-muscovite 700.
of the peaks, some remained in their original position after Li+ /K+ exchange, indicated that the removal of K+ was not complete after only once LiNO3 treatment. 3.3. OTA+ /Li+ exchange for muscovite expansion Fig. 9 illustrates the infrared spectroscopy of muscovite and OTA-muscovite 700. Three new absorption bands at 2918, 2850 and 1469 cm−1 were observed after the OTA+ /Li+ exchange. The bands at 2918 and 2850 cm−1 corresponded to CH2 asymmetric and symmetric stretching vibration modes of alkyl chain, respectively, while that at 1469 cm−1 was from methylene scissoring mode [16]. Clearly, OTA+ was detected on the muscovite after it substituted Li+
from Li-muscovite 700. In other words, the OTA+ /Li+ exchange on Li-muscovite 700 led to the formation of OTA-muscovite 700. The comparison of the XRD patterns of the Li-muscovite 700 and OTA-muscovite 700 was given in Fig. 10. It shows that the peaks moved leftward to lower angle region with the OTAC addition, suggesting an increase of the basal spacing. According to Scherrer equation, the basal spacing (d) was calculated from the 002 diffraction peak to be 2.92 nm for the OTA-muscovite 700. The OTA+ /Li+ exchange on Li-muscovite 700 greatly increased the basal spacing, from 1.21 nm to 2.92 nm. Because the thickness of the aluminosilicate layer is about 0.67 nm [17], the distance between the adjacent aluminosilicate layers of the muscovite increased 0.54 nm for the Li-muscovite 700 and 2.25 nm for the OTA-muscovite 700.
Intensity, cps
d=2.91nm (002)
(004) O OTA-muscovite 700 d=1.21nm (002)
Li-muscovite 700 7 2
3
4
5
2θ,
6
7
o
Fig. 10. Small-angle XRD diffraction patterns of Li-muscovite 700 and OTA-muscovite 700.
8
F. Jia et al. / Colloids and Surfaces A: Physicochem. Eng. Aspects 471 (2015) 19–25
25
attributed to the lower layer charge caused by the entering of Li+ into the lattice of muscovite. The OTA+ /Li+ exchange led the muscovite to expand greatly, resulting in the distance between the adjacent aluminosilicate layers of the muscovite increased from 0.32 nm to 2.25 nm. Acknowledgements This study was supported by the National Natural Science Foundation of China under the project No. 51474167. F. Jia also would like to thank the Consejo Nacional de Ciencia y Tecnología of México for offering her the scholarship under the grant No. 290733 during her Ph. D. studying. References
Fig. 11. SEM image of OTA-muscovite 700.
Obviously, the combination of thermal treatment and ion exchange could expand natural muscovite. Fig. 11 shows the SEM image of the edges of the OTA-muscovite 700. Loose framework can be observed, which was quite different from that of original muscovite as shown in Fig. 1b. This might be attributed to the expansion of the muscovite due to the increase of the basal spacing after the thermal treatment and ion exchange. 4. Conclusion The experimental results presented in this work have demonstrated that natural muscovite could be expanded through the treatments of calcination and ion exchange. The calcination only slightly opened the muscovite interlayer, about 0.02 nm, but improved the interlamellar K+ exchangeability and facilitated the following Li+ /K+ exchange. The Li+ /K+ exchange increased the basal spacing of muscovite from 0.99 nm to 1.21 nm, which might be
[1] D.A. Mckeown, M.I. Bell, E.S. Etz, Vibrational analysis of the dioctahedral mica: 2 M1 muscovite, Am. Mineral. 84 (1999) 1041–1048. [2] K. Tamura, S. Yokoyama, C.S. Pascua, H. Yamada, New age of polymer nanocomposites containing dispersed high-aspect-ratio silicate nanolayers, Mater. Chem. 20 (2008) 2242–2246. [3] M.A. Osman, U.W. Suter, Determination of the cation-exchange capacity of muscovite mica, J.Colloid Interface Sci. 224 (2000) 112–115. [4] M.A. Osman, C. Moor, W.R. Caseri, U.W. Suter, Alkali metals ion exchange on muscovite mica, J.Colloid Interface Sci. 209 (1999) 232–239. [5] Y. Zheng, A. Wang, Study on superabsorbent composite. XX. Effects of cation-exchanged montmorillonite on swelling properties of superabsorbent composite containing sodium humate, Polym. Compos. 30 (2009) 1138–1145. [6] O. Folorunso, C. Dodds, G. Dimitrakis, S. Kingman, Continuous energy efficient exfoliation of vermiculite through microwave heating, Int. J. Miner. Process. 114-117 (2012) 69–79. [7] F.A. Bottino, E. Fabbri, I.L. Fragala, G. Malandrino, A. Orestano, F. Pilati, A. Pollicino, Polystyrene-clay nanocomposites prepared with polymerizable imidazolium surfactants, Macromol. Rapid Commun. 24 (2003) 1079–1084. [8] J.W. Gilman, W.H. Awad, R.D. Davis, J. Shields Jr., R.H. Harris, C. Davis, A.B. Morgan, T.E. Sutto, J. Callahan, P.C. Trulove, H.C. De Long, Polymer/layered silicate nanocomposites from thermally stable trialkylimidazolium-treated montmorillonite, Chem. Mater. 14 (2002) 3776–3785. [9] A. Szabo, D. Gournis, M.A. Karakassides, D. Petridis, Clay-aminopropylsiloxane compositions, Chem. Mater. 10 (1998) 639–645. [10] Y. Hotta, K. Inukai, M. Taniguchi, M. Nakata, A. Yamagishi, A clay self assembled on a gold surface as studied by atomic force nicroscopy and electrochemistry, Langmuir 13 (1997) 6697–6703. [11] R. Lee, J. Lin, W. Cheng, Self-aligned nematic crystallization of poly(oxypropylene)amine intercalated silicates, Mater. Sci. Eng. C 28 (2008) 1352–1355. [12] S. Guggenheim, Y. Chang, A.F. Koster van Groos, Muscovite dehydroxylation: high-temperature studies, Am. Mineral. 72 (1987) 537–550. [13] R. Prost, V. Laperche, Far-infrared study of potassium in micas, Clays Clay Miner. 38 (1990) 351–355. [14] J.M. Rousseaux, Y., Nathan, L.A., Vielvoye, A. Herbillon, The vermiculitization of trioctahedral micas. II. Correlations between the K level and crystallographic parameters, in Proc. Int. Clay Conf., J.M. Serratosa (ed.), Div. Ciencias C.S.I.C., Madrid, 1972, 449-456. [15] Joe L. White, Layer charge and interlamellar expansion in a muscovite, Journal Paper No. 994, Purdue University Agricultural Experiment Station, Lafayette, Indiana. [16] R.A. MacPhail, H.L. Strauss, R.G. Snyder, Carbon-hydrogen stretching modes and the structure of n-alkyl chains. 2. long, all-trans chains, J. Phys. Chem. 88 (1984) 334–341. [17] X. Yu, The preparation and characterization of cetyltrimethylammonium intercalated muscovite, Microporous Mesoporous Mater. 98 (2007) 70–79.