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HWAHAK KONGHAK Vol. 38, No. 6, December, 2000, pp. 817-825 (Journal of the Korean Institute of Chemical Engineers) 817 TEOS SiO 2 * ** , * ** (2000 4 28 , 2000 9 18 ) Influence of Reaction Conditions on SiO 2 Supersaturation and Particle Size in TEOS Sol Precipitation Kyung-Soo Kim, Sung-Soo Kim, Sun-Keun Kim*, Joon-Kyung Kim** and Woo-Sik Kim Department of Chemical Engineering, Kyunghee University Yongin, Kyungki-Do 449-701, Korea *Department of Chemical Engineering, Joongang University Dongjak-Ku, Seoul 156-756, Korea **Department of Polymer Engineering, KIST, Dongdaemoon-Ku, Seoul 136-791, Korea (Received 28 April 2000; accepted 18 September 2000) TEOS(Tetraethylorthosilicate) TEOS , , , . TEOS . , . , . . , . . Kim [15] . , . Abstract - In a single feed semi batch reactor effects of reaction conditions, such as TEOS and water concentrations, reac- tant feed flow rate and agitation speed, on the silica supersaturation and particle size synthesized in sol precipitation were investigated. As the TEOS and water concentrations increased, the particle induction time and the supersaturation at the par- ticle induction point were reduced. However, the dependencies of the particle induction time and supersaturation at the particle induction point on the reactant flow rate were opposite to each other. That was, the particle induction time decreased with increase in the reactant flow rate but the supersaturation at the particle induction point increased. The fact that the supersatu- ration level to induce the particle was varied with the reaction condition implied that the solution condition determined by the reaction conditon as well as the supersaturation level was important to the particle induction. Meanwhile, the particle induction time and supersaturation at the particle induction point were little influenced by the agitation speed in the reactor. This result was due to the micromixing time being short enough in comparison to the reaction time of TEOS. Thus, the particle induction time and supersaturation at the particle induction point was predominantly determined by the reaction time rather than the micromixing time of TEOS. The reaction rate constants of TEOS hydroysis and condensation, which was predicted with Kim et al.’s equations [15] at the reaction conditions was described as a function of the particle induction time. In addition, the par- ticle size synthesized at the reaction conditions was able to be well fitted as a function of the particle induction time. Key words: Sol Precipitation, Reaction Condition, Particle Induction Time, Hydrolysis/Condensation, Supersaturation, Parti- cle Size E-mail: [email protected]
Transcript

HWAHAK KONGHAK Vol. 38, No. 6, December, 2000, pp. 817-825(Journal of the Korean Institute of Chemical Engineers)

TEOS � ������ SiO2 � �� �� ��� ��� ���� ��

�����������*����**��†

����� �����, ���� *����� �����**���������

(2000� 4� 28� ��, 2000� 9� 18� ��)

Influence of Reaction Conditions on SiO2 Supersaturationand Particle Size in TEOS Sol Precipitation

Kyung-Soo Kim, Sung-Soo Kim, Sun-Keun Kim*, Joon-Kyung Kim** and Woo-Sik Kim†

Department of Chemical Engineering, Kyunghee University Yongin, Kyungki-Do 449-701, Korea*Department of Chemical Engineering, Joongang University Dongjak-Ku, Seoul 156-756, Korea

**Department of Polymer Engineering, KIST, Dongdaemoon-Ku, Seoul 136-791, Korea(Received 28 April 2000; accepted 18 September 2000)

� �

� ����� � ���� TEOS(Tetraethylorthosilicate) � �� ���� ��� �� ���� TEOS ��, �

��, � � �� �, !� � "# � $%� ��� &'( �� ) �*+,� -.� /0� 12 ���34.

TEOS � �& � ��5 65789 �*:��;< =>?@A �*:��B��# &'( ��� CD�34. EFG,

� � �� �5 �*:��;& �*:��B��# &'( ��� -.� /0< �H I�JK4. L, � � ��

�# 65� MN �*:��;< CD�3@G �*:��B��# &'( ��� 65�34. � $%� MN �H 4

O &'( ���� �*5 :�J� P< �*# Q�� RS� &'(� �T# �U# $%�� /0� V4� P�

#-�� P�4. WX, !� �� �*:��;& :��B��# &'( ��� Y# /0� �Z [\4. �P< � �

��� � � ]��;� ^�_ => ��� `�� RS� � �5 �*:� ) &'( �� a�� 5b +c

/0� -d, ef�4. � $%� MO 58�2 ) g� � �h Kim "[15]� i�W j� ���� kl�3@

A � a&� � �m�� l�W �*:��;# n8H� op q rst 8 RK4. uW, � $%� MN ��v w

x�*# +, y(� �*:��;# n8H z{_ rst 8 R|� }� �K4.

Abstract − In a single feed semi batch reactor effects of reaction conditions, such as TEOS and water concentrations, reac-

tant feed flow rate and agitation speed, on the silica supersaturation and particle size synthesized in sol precipitation were

investigated. As the TEOS and water concentrations increased, the particle induction time and the supersaturation at the par-

ticle induction point were reduced. However, the dependencies of the particle induction time and supersaturation at the particle

induction point on the reactant flow rate were opposite to each other. That was, the particle induction time decreased withincrease in the reactant flow rate but the supersaturation at the particle induction point increased. The fact that the supersatu-

ration level to induce the particle was varied with the reaction condition implied that the solution condition determined by the

reaction conditon as well as the supersaturation level was important to the particle induction. Meanwhile, the particle induction

time and supersaturation at the particle induction point were little influenced by the agitation speed in the reactor. This result

was due to the micromixing time being short enough in comparison to the reaction time of TEOS. Thus, the particle induction

time and supersaturation at the particle induction point was predominantly determined by the reaction time rather than the

micromixing time of TEOS. The reaction rate constants of TEOS hydroysis and condensation, which was predicted with Kim

et al.’s equations [15] at the reaction conditions was described as a function of the particle induction time. In addition, the par-

ticle size synthesized at the reaction conditions was able to be well fitted as a function of the particle induction time.

Key words: Sol Precipitation, Reaction Condition, Particle Induction Time, Hydrolysis/Condensation, Supersaturation, Parti-

cle Size

817

†E-mail: [email protected]

818 ���������������� �

1. � �

���� ����, ��, ��� � �� ���� �� ��

���� �� ��!". #$! %& '( �)*� +, -

. /01 ��� �2� 34 56� 7�8� �". !9 �21 /

0: ;'8� �� <54 =�>�� �2 ?�1 @A, BC, D

E D �F �! �GH !9 =�� �2: I�> 8� 0J K

;L': MN OP�� O�1 Q0: ;'8� �� <54 5K

� R". +,� ��� �2 OP�� !9 =�, QS ?�1 BC,

D D�FT O)8� U. V. W61 3X! �)Y� �"[1].

�� �2: OP8 Z4 3[\= ]^G> _ `�^! �".

! ]^. I� ab/1 �c�de fg ab: h8� ij�� k

l �m?�1 n>!o pqr Xs= _: t0uv kl ?�T O

P8� �� �� wxy ]^!". ! ]^. -. @A1 I� ab

/: ��8� �@A1 kz�T OP{ |} ~�, ?�1 0� E

P0: O)8 �!8". �4, �2OP1 ��� �)� ?�1 D

e Js �1 P�! �!4 ��A ��� �"[2, 3].

Stober� 1d ��� w��!o ab/: !�8� 6J1 &�#

SiO2 �� �2: g0{ c �"� U! OuR !� w��!o

�c �d/fg ab� 14 �� �2 OP� %& K�� ��

OPT Z4 ]^G> V. W61 3X! ��". V. W6�� _

`�^(sol precipitation)� 14 SiO2 �2 OPu ab/= ��� w

��!o1 �c�d/fgab1 ab����: ��! !�)� �".

#0!� w��0 �r ��� w��!o� #(H+) �. w��

(OH−)1 �� ��� 1d �c�de fg! !�)y". ��

�k>� ��. #1 �� ��8��� ��� t0/! ��Js

> W;R �> ���H w���r ���� _Js1 ?�9> t

0/! ���� U!". +,�, ��� w��!o>�� �c�d�

14 ��� �2 OP� �)� abP� QS, ��� +� �2Q

01 � � ��   W63X! �A 8¡". ��� �2: OP

8 Z4 ¢" ��\ W6>�� _ `�£'�� ��1 abP�

¤, ab/1 ¥A(��� w��!o, /), w¦§ medium1 ¨©�

t0�� ?�1 BC� D� kª� «¬ �� 34 W6� V!

­8� ®"[1-6]. � < Chang �[6]. a¯�° ab�� ab�

±² ³5 P$�c91 � � +� ?�1 BCL D1 «¬: ´

µ¢¶". �9 3��1 W6� _ `�£'G> 6J1 ?�T g0

{ c �� abP�� ³> ±·: �� �¸\ W6T c­8¡G�

_`� £'�� ?�1 t0 E 0�1 ¹º0G> =d ?�1 D

E BC O)T Z4 £� ����: Ou8�� »8¡".

_ `� £'�� SiO2 ?�� 0�8� I�T ¼�8 Z4 ��

��G> �� V! \��� �� B½>� monomer addition B½[4, 5]

L aggregationB½[7, 8]! �". Monomer additionB½. LaMere

Dinegar[4]� 1d ¾¿G> Ou��". �c�d/fgab� 1d �

r �� ��� LF � t0�H �> =8� ��� ?�� t0�

H t0R ?�� LF �r<1 ��� ?�1 [À� !Á8�

integration�À� 0�4"� 8¡". W6;L� 18À, Â. Ãt0

Ä: h8� BÅ ?�Ã9! t0��, t0R ?�9. ‘self-shar-

pening growth’� 18� 0�8Æ> &�#1 6J?�� Ç)y"�

¼�8¡". !e È�4 ÉÊ1 ?� 0� B½>� Nakanishi �[9]

. 2ËI\ "Ã 0� B½(two-dimensional polynuclear growth model)

! �". LF �r <1 ��� ?�> !Á8� integration��

L'! "Ãt0L'� 1d !�)y"� ³�4 U! ! B½! LaMer

e Dinegar1 B½L1 kK4 Ë!�!". ÌÍ Chen[10] �A !e

È�4 ÉÊ1 ?�0�: Î�8 Zd Ï#0� B½: Ou4 Ð

�".

Matsoukase Gulari[11, 12]� TEOS>�� n>!o ���?�1 t

0 L': '( �Ñ8� ?�1 0�. ?� [À��1 �� integration

� 1d ;'R"� ��8¡GH !T hd� LaMere Dinegar� O

u4 ����1 �Ò0: Ï=uv ³�". !9 ;L� 18À, ÓÔ

&= TEOS1 �c�d� 18� Õ0 0�= ��� ¨(species)!

J0�H, Ãt0. �#&Öm1 fgab� 18� ×)Ø". Ã. ?

�D� «¬: Ù� &Öm %�ÔA� 18� 0�8H, ! ���

?�[À� 34 &Öm %�ÔA� Ãt0ÔAT Ú�8À Ãt0.

'�4"� ³�8¡". ��� TEOS1 KBÔA� ?�1 0�ÔAe

Û"� U: ÜÝGH, !� +, TEOS1 �c�d&� ÓÔ&,

� ;Þ: �ß".

4à, aggregation B½. Bogushe Zukoski[7, 8]� 1d Ou��

". ! B½� 18À LF �r ��� t0�� Ã?�(nucleus

particle) 1 nm!81 �� �. ?�>� -. interaction�á�> =

8� c µs!�� bâ8� ã'\G> ä�{ c �� ÌKD1 ?

� ¤, 1Ë?�(primary particle)> �åR"� 8¡". !æç ��Ø

1Ë ?�� ä1 ?�e �. 1Ë?� �!1 èé� 1d ?�1

0�� ê�8"� ¼�8¡". &�#1 ?�T J08�ë �)�1

aggregation growth model1 !ÞL ��� w��!o>�� Ç)ì

6J1 ?�9� 34 t0ÔAe ?�D �F� 34 �¸\ dataT

íî8� ! B½1 �Ò0: 7�8¡". ! B½. _-� £'��

&uÄ �� c µm D1 ?� J0: ¼�d ³� �� \�4 B

½> ij�� �".

���, ï�1 3��1 W6��� w��!o �c�d� 14

SiO2 �2 OPu� ?�1 0� I�T ¼�8��8� B½� 34

W6� ³> ­8�®". ��Æ>, w��!o �c�d� 1d OP�

� ?�1 t0ÔA E ?�1 0�ÔAT dÑ8x� ðñ. "K �

ò8¡". �4 �O1 TEOS �c�d� 14 ��� ?� OPu ?

�1 0�. monomer addition B½!� aggregationB½ 4��}G

>� è�4 dÑ! ó�Ú4 ��� V! ���� �". YSx ô

B½1 ����! ¹g\G> õg�) ?�0�! !�)�� ö4

;LT ¢� ³� �G� pX1 ¹º0G> =8� c�\ B½1 O

u� M1 !�)�� ÷� �".

+,� ø W6��� �� �� _ `� abP�8�� SiO2 ?�

1 0�ÔA� ±4 ù W6T c­8�� 4". abP�� +,

TEOS1 �c�d/fgab ÔA� «¬: ÙGH !> =8� �r�

1 LF ¥A� �{ c �". !e Û. � � ��� ?�1 t

0 E 0�� «¬: ³) ̨ Ç)�� ��� ?�1 D� V.

«¬: ³�, úXR". ûB�~ ��1 � � +� LF ¥A1

� � +� ?�1 t0 E 0�� kª� «¬� 3d�� KimL

Kim[13] �� 1d c�\ B½: hd dÑR Ð �". ø W6��

� TEOS¥A, /¥A, ab/³?ÔA, îaÔA �1 abP�1 �

� +� SiO2 LF ¥A � T ´µ¢H !U! SiO2 ?� D

� kª «¬� 3d ��d¢�� 4".

2. � �

_ `�£'�� ��� w��!o� /� 1d �c�d�) silane

: t08H !U. fgab: hd ̨ t0/= ���> �å�ç

R". !e Û. ��� g0ab. "¿L Û! üü Äý8ç [p

4"[14].

(1)

(2)

�� R. wþT 1k4". �c�d� 1d Ç)�� silane.

Si OR( )4 x H2O Si OH( )4 OR( )4 x– x ROH+=+

Si OH( )4 SiO2 H2O+=

���� �38� �6� 2000� 12�

TEOS� Sol � ���� ����� �� 819

���> �å� Z4 <Ä/ÿ>� abL'�� � 'XXs�

È�R"� �'8À ��� w��!o1 �c�d/fgab. "¿

L Û! ײ1 WÔ abG> [u� c �"[7].

kl k2Si(OR)4� SiO−

�SiO2 (3)

��� w��!o1 ab°: 1Ë WÔab°G> �'4"À ��

� w��!o ab�r! ×'4 ÔA> È?�� a¯�° ab

��� �c�d/fgab! y­� � !� 34 ü 0�� /ÿc�

°. "¿L Û! [p� c �".

(4)

(5)

(6)

�� k1L k2� �c�de fgab &1 abÔAXcT ��

�� [Si(OR)4]0� w��!o ab�r1 ¥A, Q� w��!o a

b�r1 ³?ÈÖ, V� ab1 �r ��(V = V0 + Qt)T 1k4

"(V0� ù ab�1 �r��). Seed� ä�8� ÷� �� °

(4)-(6)1 c�\ d� "¿L Û! Ou� c �".

(7)

(8)

(9)

° (7)-(9)T hd a¯�° ab�� uÄ� +� ab/, <Ät

0/(silane), ̨t0/(���)1 ¥A � T ú�8 Zd�� �

�� w��!o1 �c�d E fgab1 ÔAXc�: �5> 4".

!e Û. abÔAXcT �'8 Z8� Bogushe Zukoski[7], Yoon

�[16], KimL Kim[13] �. conductivity E \'^: !�8� u�

+� silane1 � ¥AT �'8¡GH ! ;LT ° (8)L íî8�

]^G> abÔAXc�: ;'8¡". QS, Kim �[15]. ��� w

��!o ab/ ¥A, / ¥A, ûB�~ ¥A, ab/ ³?ÔA �1

abP�� +� abÔAXcT Z8ç �'8¡GH ! abÔA

XcT abP�1 �c> [u8¡". +,�, !9! Ou4 °: !

�8� ø W61 abP�: 3?8� �c�d E fgab1 ÔA

Xc�: #8¡GH !U: !�8� uÄ� +� �r �1 ¥A

� T ú�8¡". �� ê�d� { ��. ° (6)1 �� ab

�1 SiO2 /ÿc�� ab� 1d t0�� U} �x��GH SiO2

?�1 t0 E 0�: Zd Kí�� U. �x8� ÷. U!". +

,�, ° (6)L (9)� �r ��� ?�� t0� � � ¤, ?� È

AÄ(particle induction period) ���} È�8"� U!".

3. � �

ø W6��� _ `� £'� 1d ��� ?�T g08 Zd�

Tetra ethyl ortho-silicate(TEOS, Fluka, ACS grade)T ab/> ��

8¡". TEOST ��§ ��� �duv 100 ml ab�r: }9�".

TEOS1 �c�d/fgab: Z8� # �. w��0 �r! ��>

!�R"[14]. ×a\G> monolith Js1 ���0 �: g08� �

��� HClL Û. #0�r! !��H �2L Û! ?�J _: t

08 Zd�� w��0 �r! ��> !�R". ø �¸��� û

B�~�r: TEOS ab1 ���rG> ��8¡".

ûB�~, / ��� �#��>�1 ��§ õg�r 330 ml: ab

� k� �~ ô� �� 100 ml1 TEOS ab�r: ³?8� a

b: ÈA8� ?�T g08¡". ab� [�J Rushton ab�

��) ¼8¡". ab� 6-paddle Js1 îa� <·� ¼ª�

) ab/: õg8¡GH ab �À� 4É1 ��]d�(baffle)!

¼ª�) îa� 14 õg: ¢" �L\G> d³�". ab�

pyrexÈ�>, ��]d�. ��4 ~D��G> O�8¡". �4 îa

� stainless steel> }9)®GH heterogeneous [À! ?�1 2Ë

Ãt0 �� kª� «¬: ÌK 8 Z8� �. #G> [À ¾�

� ù@c> l�8¡".

abP�! SiO2?�1 t0 E 0�� kª� «¬: P�8 Z

8� TEOS ab/ ¥A, /1 ¥A, ab/ ³?ÔA, îaÔA �1

P�: � uv ³�". TEOS ab�r1 ³? ��� 100 ml> �

X ×'8ç �'4 Xs�� TEOS1 ¥AT 0.11-0.45 mol/L � �

uv ³�". 100 ml1 TEOS ab�r. Syringe pump(ATI orion,

model 361)T !�d� ab� �×4 ÔA> ³?��". ab ³

?ÔA� 0.5-10 ml/min> � uv ³�". TEOS1 �c�d ab�

ê�8� /. abu� � ab� �� õg�r� F��) �G

H /1 ¥A� 2.2-22.5 mol/L � � u�".

ab �1 �c�d/fg abÔAT ±�8 Z8� TEOS ab

�r! ³?�� Áã ab � �r1 silane ¥A� T �'8¡".

ab�� ×'4 uÄ Ä�G> 5 ml1 �r: !8� @c4 �

�§ �r� "Ñ8¡GH TEOS1 �c�d/fgab! y­�� U:

#¶". !æç !R u� �r: ûB�$ %�&ë! �r: !�

8� \'�G>� uÄ� +� �r �1 silane1 ¥A� T �'8

¡". ! \'^. ûB�$ %�&ë!'� �r <1 silaneL ab

8� ���%�&(#G> Ð)ç R". \'ab! *��À� �r

1 +,! ��4 Xs�� -+G> �å�� u�: ±��G>�

�r �1 silane1 ¥AT �'8� I�!". ! \'^� 34 �l

4 �¸]^ E �Ë� Iler[17, 18] E Yoon �[16]� 1d .�)

�". �4 UV /AT !�8� TEOS ab�r! ³?�� Áã

�c�d/fgab� 1d ¾¿G> ��� ?�� t0�� uÄ, ¤

?�ÈAuÄ(induction time): �'8¡". TEOS ab�r1 ³?!

*�R � ab �1 �r: kl��(microfilter)T !�8� ?�

e �r: ��8¡GH ��R ?�� Zetasizer(Malvern, UK)e �

�pk�(SEM, Leica 400, Germany): !�8� ?�1 0� De

BC: üü �'8¡".

4. � ��

_ `� £'� 1d �2?�� OP�� Íø\ 1�� ��� L

F �r ��� ?�1 t0L 0�� 1M4". TEOS ab/! �

c�d/fgab: hd ���� g0��} ���� �� 2. �d

AT ��� �GÆ> g0R ���� óã'4 Xs(labile state)1

LF > ä�4". ! LF �r. 34�\G> �� óã'8�

�r �� �äXs> ä�8� »8� ��� �m> Ñ5�ç R".

¨�?�� ä�8� ÷� �r ��� ��� LF ¥A� Kí��

L'. ô ��> �6 c �". ¾¿, �r �� ��� ?�1 Ãt0

! ×)�� U!H !æç t0� ?�� LF �r ��� 0�8

� U!". ! ô �� L'�� �c\G> ��� ��T �5> 8

Æ> �r� ä�8� ��� �m��> � �ç R". ! L'��

d S OR( )4[ ]dt

--------------------------Q Si OR( )4[ ]o

V-------------------------------- k1

QV----+

Si OR( )4[ ]–=

d SiO –[ ]dt

--------------------Q Si OR( )4[ ]o 1 k1t–( )exp–( )

V-------------------------------------------------------------------- k2 SiO –[ ]–

Q SiO –[ ]V

----------------------–=

d SiO2[ ]dt

------------------- k2 SiO –[ ]Q SiO2[ ]

V---------------------–=

SiOR[ ]Q SiOR[ ]0

k1 V0 Qt+[ ]--------------------------- 1 k1– t( )exp–( )=

SiO –[ ]Q SiOR[ ]0

V0 Qt+-------------------------

1 k2– t( )exp–k2

------------------------------- exp k2t–( ) k1– t( )exp–

k2 k1–----------------------------------------------------

+=

SiO2[ ]Q SiOR[ ]0

V0 Qt+-------------------------=

t 1 k2– t( )exp–

k2

-------------------------------– 1k1

----- 1 k2exp k1t–( ) k1 k2– t( )exp–

k2 k1–---------------------------------------------------------------–

HWAHAK KONGHAK Vol. 38, No. 6, December, 2000

820 ���������������� �

ù� ?�� ä�8� ÷� �r �� ��� LF � 1d ?��

¾¿G> t0�� U: ?�ÈA(particle induction)!, 4". ×a\G

> LF Xs� �À �r. óã'8� �m> Ñ5� �Ú0. �

". ��� LF ¥A1 'A� 2. �� ?�� t0�� ÷. �

ã' «4(metastable region)! �GH ! «41 D� /ÿ� +,

Ë!� �". �4 ?�1 t0ÔA� LF ¥A� 1ä4". LF

¥A� -GÀ ?�1 ÔA� 78H ¥A� 2GÀ � a3� R".

��Æ> �r �� LF ¥A� J0�9,A ?�1 :Ð> t0

�� U! ~�, ×'uÄ1 �LT �5> 4". abu��� �r

��� ?�� ¾¿ t0�� @Ä �1 Ä: ?� ÈAÄ(particle

induction period), 8H ?�� ¾¿G> t0�� u�: ?� ÈA

uÄ(induction time)!, 4"[14]. t0�� ?�1 ;c E ÔA�

�r �1 SiO2 LF ¥A� <=\G> 1ä8Æ> �r ��� y

­�� TEOS �c�d/fgab1 abXce Ìù1 ?�� J0��

ÈA uÄ1 �'. �� <58H !T hd� ?� ÈAu���1

SiO2 LF ¥A1 ú�L !U! ?� t0, 0� E D� kª�

«¬: dÑ{ c �ç R".

_ `� £'�� abP�1 � � +� ?�ÈAuÄ1 � T �

'8¡". TEOS ab/! ab� ³?�� Áã �r ��� SiO2

?�� ¾¿G> t0�� ÈAuÄ: �r1 UV �LA(transmittance)

T !�8� �'8¡". ?�� ä�8� ÷� ��4 �r� TEOS

ab/ ³?: u�8À �r �� ?�� t0� ��� �r1

UV �LA� 100%T È�8¡G� ?�� t0� u�8À���

UV �LA� >�8ç *K8ç R". �4 uü\G>A �r ��

?�� ¾¿ tÀ ?. ��4 �r�� W@�+1 �rG> �8

¡GH ! u�: ?�ÈAuÄG> ij8¡". !æç ô �� ]^

G> �'R �. 5%!�1 XA YË ��� ת8¡". �O> ?

�ÈAuÄG> �'�� �. �r �1 ��� LF Xs�� ¾

¿G> ?� t0R @Ä1 �! ~�, �O uü\G> �. UV�

LA� � T kª� 'A1 ÌK ?�> 0�B: �!".

Fig. 1�� ¢� Ðe Û! TEOS ab/1 ¥A� 7�{cC ?�

ÈAuÄ! >�S *K8� U: w c ��". ! �� / ¥A�

2.5 mol/l, ûB�~ ¥A� 0.89 mol/l, ab/ ³?uÄ. 30 min, î

aÔA� 900 rpm> ×'8ç È���". TEOS ab/ ¥A, QS

TEOS ab/ ¥A� 0.11 mol/l1 �� ab/ �r! Bô ³?�

� � �r �� ?�1 t0! ×)�� ÷¶GH ab/ ³?� 10

��Ä: �Ô\G> Û. P�G> È���: � í>K ?�1 t

0! �'��". !U. 2. ab/ ¥A��� �c�d/fgab1

ÔA� D�Æ> �r�1 LF J0! X3\G> D�ç !�)y

". TEOS>�� ��� g0ab1 �� �c�d abÔA� ÓÔ&

E. !k wxy pX!". �Fë ï1 ab°�� [pR Ðe

Û! �c�d abÔA� TEOS ¥A� 1ä4". +,� TEOS a

b/ ¥A� 7�{cC �c�d abÔA� 7�8H !> =d �

r �� J0�� LF J01 ÔA� 7�8� ?�ÈAuÄ! *

K8� UG> ��Ø U!". ! �¸;L�� G>8� H. U.

�c�dabÔA� TEOS1 ¥A� 1Ë> íI8� UG> [p��

GÆ> �r� LF ¥A1 7�A TEOS¥A� 1Ë> íI8� U

G> ú�{ c �GH ;L\G> Û. LF ¥A�� ¾¿ ?�1

t0! !�)y"À ?�ÈAuÄ. TEOS ab/ ¥A� aíI8ç

��J UG> úXR". ��� �¸;L1 �� ?�ÈAuÄ1 *K

� TEOS ab/ ¥A� 1Ë aíI8� U¢" 9 >ÔS *K8�

UG> ��K". !U. ¾¿ ?�1 t0. abP�� ±8ç ×

'4 LF ¥A�� ×)�� U! ~�, ?�1 t0. LF ¥

A|} ~�, abP��A Áu� 1ä8� U: ��L 8� U!

".

/ ¥A1 � � ?�ÈAuÄ� kª� «¬: ±�8¡". /.

TEOS1 �c�d� ê�8� ab/!". ��� _ `�£'�� /

1 ¥A� TEOS1 ab/� íd LA4 L¥A Xs�� ab! y

­�Æ> ×a\G> / ¥A1 � � �c�d abÔA� «¬: k

ª� ÷. UG> �'4". !�4 �'8�� �c�dab: TEOS

¥A� 1Ë> íI8� °G> [p8� U!H V. W6� !�)y

�". ���, Kim �[15]. abP�! TEOS �c�d/fgab

� kª� «¬ P��� �c�d abÔA� /1 ¥A� 1ä8�

U: �¸\G> ÜM Ð �". !9. Z4 ¥A � �¸��

/ ¥A1 7�� +, �c�dÔA� 7�8¡GH �> =d -.

LF ¥A� J0R"� 8¡". !9 W6 ;L� 18À TEOS1

�c�d/fgab: 1Ë ab°> ij8¡: � abXc� /1 ¥

A� +, �8� UG> /¥A1 «¬: ��N". ���, ×a\G

> TEOS ab�� OS \��� /1 ¥A Z��� �c�d a

bXc� / íî\ 2ç 1ä8� UG> ��� �c�d/fgab:

1Ë ab°> �'4 U!   YËT ÈPª� ÷. UG> �&8¡

". ø �¸�� Fig. 2� ��Ø Ðe Û! 2.2-22.5 mol/l1 Z

4 / ¥A � �� ?�ÈAuÄ! � 8� U! ±���". QS,

/1 ¥A� 2. ��(2.2 mol/l)1 �� �� -. ?�ÈAuÄ: �

�� UG> ��K". ��� /1 ¥A� 7�8À� ?� ÈA u

Ä. >ÔS *K8¡GH 4.5 mol/l!X��� �� *}8ç *K8

� UG> ��K". !U. /1 ¥A� 2. �� �c�d� «¬

: Ù~ abÔA� Dç i8��GH �> =8� ��� LF ¥

A1 J0! X3\G> Q)R: 1k8� U!". Stober �� 18

À /. TEOS �c�d�� !Þ\G> 4 : 11 í> ab8�} �

O ab�� 6J1 ��� ?�T Ç Zd�� /1 ¥A� TEOS

¥A� 20S !X! �)� /� 14 «¬! \ç ��Ø"� ³�8

¡". !U. ø �¸�� Ç. /! ?� ÈAuÄ� kª� «¬1

;Le ×TXh8� ;L!". �4 Kim �[15]! ¢�� �c�dÔA

� /1 ¥A� 1d � 8� �¸;LeA ת8� U!". !�4

��. V. _-� W6�� /1 ¥AT TEOS� íd ��ªç LÖ

Fig. 1. Effect of TEOS reactant concentration on silica particle induc-tion time of sol precipitation in semi batch reactor. Other reac-tion conditions were fixed at 2.5 mol/l of water concentration,0.89 mol/l of ammonia concentration, 30 min of feeding time and900 rpm of agitation speed.

���� �38� �6� 2000� 12�

TEOS� Sol � ���� ����� �� 821

1 Xs�� ��� ?� g0: 8� U��A U wx� �".

?�ÈAuÄ. ab/ �r1 ³?ÔA�A V. «¬: Ù� UG

> �'��". Fig. 3�� ¢� Ðe Û! ab/ ³?ÔA� 7Tc

C ?�ÈAuÄ. Dç *K8¡". ab/ ³?ÔA� -:cC ab

�r �� f\�� TEOS ab/1 ¥A� 7�8ç �H !�

�c�d abÔA1 7�T ÈP8� VW\G> ?�ÈAuÄ1 *K

T ���". _-�£'�� �c�d/fg1 abÔA� íî\ DX

U: �x4"À ab/ ³?ÔA(0.5-10 ml/min)� ab� 14 �å

ÔA ¢" Y, �r �� ab/! f\� c �� è�8¡". Q

S, ab/ ³?ÔA� 2. ��(Z 5.0 ml/min !8)��� ?�ÈA

uÄ! ab/ ³?ÔA� aíI8� *K8¡G� -. ab/ ³?

ÔA��� ?�ÈAuÄ! ³?ÔA� M1 «¬: Ù� ÷. UG>

��K". !e Û. ?�ÈAuÄ� 34 ab/ ³?ÔA1 «¬.

TEOS ab/ ¥A� 2:cC 9[ \]8ç ��K". ab/ ³?

ÔA� �g0� 1d ?�T OP8� £'�� �� <54 �c

��ë 4 ��". ¤ Z��A G>4 Ðe Û! ab/ ³?ÔA�

+, ��� t0ÔA� «¬: ÙGH !� �r �1 LF AT ;

'8� ³54 �c� R". LF A� +, ?�1 t0L 0�!

;'�Æ> _-� £'� 1d I8� D E D �F� ;'�ç

R". ¤, ù� t0R ?�� 1d �c�d/fgab: hd �Ô\

G> t0�� ���� è�S Kí� R"À �r�1 LF ¥A

� �Ô1 ?� Ãt0^! �Ô\G> 0�8� &�F1 ?�> O

PR". aÀ, ?�1 0�� 14 ���1 Kí� ab� 1d t0

�� ���1 t0� kª� »8À ���� �r� f\�) LF

A1 X_: �u`H !� �Ô1 ?� Ãt0G> !)� ̨

OPR �r�� �> "� D1 ?�� ä�8ç R".

�r1 îaÔA� ��� ?�T OP8 Z4 _ �£' W6u

� OS9 �x�� ÷. �c��ë 8�!". ��� ChangL Kim

[6]� 18À îaÔA� +, _ `�£'� 1d OP�� ��� ?

� D� Dç «¬ Ù� U: ±�8¡". !9! ±�4 �¸;L

� îaÔA� ��� _ `�£'� «¬: kª� U: 7�8� U

!Æ> ø �¸��� îaÔA� ?�ÈAuÄ� kª� «¬� 3d

P�8�� 8¡". Fig. 4�� ¢� Ðe Û! îaÔA� 7���

+, ?�ÈAuÄ. "K *K8¡". îaÔAT 400-1,600 rpm �

� u�: � ?�ÈAuÄ. Z 10%'A1 � � ��K". ! '

A1 � � ï�1 abP�1 � � +� ?�ÈAuÄ1 «¬�

í8À �� kk4 � 'A,� �&{ c �". ø �¸;Le

ChangL Kim[6]1 ;LT ¨g �Ñ8À _-� £'� 1a ���

Fig. 2. Effect of water concentration on silica particle induction time ofsol precipitation in semi batch reactor. Other reaction conditionswere fixed at 0.224 mol/l of TEOS reactant concentration, 0.89 mol/lof ammonia concentration, 30 min of feeding time and 900 rpm ofagitation speed.

Fig. 3. Effect of feed flow rate of TEOS reactant solution on silica par-ticle induction time of sol precipitation in semi batch reactor.Other reaction conditions were fixed at 2.5 mol/l of water con-centration, 0.89 mol/l of ammonia concentration and 900 rpm ofagitation speed.

Fig. 4. Effect of agitation speed on silica particle induction time of solprecipitation in semi batch reactor. Other reaction conditionswere fixed at 2.5 mol/l of water concentration, 0.89 mol/l ofammonia concentration, 30 min of feeding time and 0.224 mol/lof TEOS reactant solution.

HWAHAK KONGHAK Vol. 38, No. 6, December, 2000

822 ���������������� �

?�� OP�� L'�� îaÔA� ��� LF t0 !�� �

�� ��� 1d ?�� t0�M� 0�8� L'� «¬: kª�

UG> �Þ{ c �". ! L'. ?� D E �FT ;'8� �

� <54 L'G>� V. W61 ±·! �� U!�".

Kim �[15]. TEOS1 �c�d/fg ab: 1Ë ab°> 8¡:

� �c�d E fg abÔA Xc(k1L k2)T TEOS ab/ ¥A,

/¥A, ûB�~ ¥A �1 abP� �c> [u8¡". ø bc��

� !91 ±°: !�8� ú�R �c�d E fg abÔAXc

e ø �¸�� �'4 ?�ÈAuÄL1 X±±T 6d ¢¶". ?

�ÈAuÄ. �r �� J0�� ��� LF ¥A� 1d ³> ;

'�H ! LF ¥A� TEOS ab/1 �c�d/fg ab� 1d

t0�Æ> abP�� +� �c�d/fg abÔAXce ?�ÈAu

ÄL� �� (=4 X±±� �G�, úX� �c!". Fig. 5e

6�� ¢� Ðe Û! ø �¸�� abP�� +, �'R ?�ÈA

uÄ! Â:cC �c�d E fg abÔAXc� 7�8¡". !�

TEOS1 �c�d E fg abÔA� 7�{cC �r �� ���

LF ¥A� >ÔS 7�8H +,� ?� t0� c �� LF P

�� ¢" Y� Ad8¡¿: 1k8� U!". Kim �[15]! Ou4

±°: !�8� ø �¸�� c­R abP���1 abÔAXc�

k1! k2� íd �ç ú���GH !�4 ;L� TEOS abÔA�

³> �c�d� 1d ;'R"� ä1 ;Le ת8� U!". �

4 ø �¸�� ú�4 abÔAXc� Bogushe Zukoski[7] �! O

u4 abÔAXc�L È�4 UG> ��K". ?�ÈAuÄL �c

�d abÔAXce1 X±±� �� �. àË ��� \]4 �

¬: ¢�³� �G� fg abÔAXce1 X±±�e "K1 à

Ë� �� UG> ��K". ��� "­SA TEOS ab. �c�d

ab� 1d ÓÔ�Æ> �m\ abÔA��� �� àË� �. X

±±T �ÿ UG> fç úX{ c �".

!e Û! ú�R �c�d E fg abÔAXcT !�8� ° (9)

>�� ?�ÈAu���1 ��� LF ¥AT ú�{ c �".

Fig. 7�� ¢� Ðe Û! TEOS ab/1 ¥A� 2. �� �� -

. LF ¥A�� ?�� J0��GH TEOS ab/! 7�{cC

?�T ÈA8� LF ¥A� >ÔS *K8¡". !U. TEOS a

b/1 ¥A� 2:cC ?�ÈAuÄ! Dç ���� UL� ת�

� pX!". ���, abP�� +, ?�ÈAu���1 LF ¥A

� �8� U. ?� Ãt0! LF ¥A|} ~�, abP�� 1

d�A «¬: Ù�"� 7M!". 4à, LF ¥A� -. Xs��

?�� ÈA� �� �� -. Ãt0G> =8� V. Éc1 ?��

���Æ> ̨ ?�1 D�A V. «¬: kª�, úXR". !

� 34 �l4 ¼�. g�� G>8¡".

Fig. 5. Correlation of hydrolysis reaction rate constant with particleinduction time within variation ranges of reaction conditionsapplied in this study.

Fig. 6. Correlation of hydrolysis reaction rate constant with particleinduction time within variation ranges of reaction conditionsapplied in this study.

Fig. 7. Effect of TEOS reactant concentration on silica supersaturationat particle induction point in sol precipitation. Other reactionconditions were fixed at 2.5 mol/l of water concentration, 0.89mol/l of ammonia concentration, 30 min of feeding time and900 rpm of agitation speed.

���� �38� �6� 2000� 12�

TEOS� Sol � ���� ����� �� 823

abP�! ?�ÈA� «¬: kª� 7M� Fig. 8�� ¢� Ðe

Û! / ¥A � � +� ?�ÈAu���1 LF ¥A � 1 �

¸;L��A ��K". / ¥A� 2. �� ?�ÈAu��� J0R

��� LF ¥A� �� -¶GH / ¥A� 7�{cC >�S *

K8� 5.0 mol/l !X1 ¥A��� ?�ÈAu���1 LF ¥A�

M1 ×'4 c�: ����". !e Û. úX. / ¥A � � ?

�ÈAuÄ� kª� «¬LA ×±R ;L!".

TEOS ab/1 ³?ÔA� ?�ÈAu��� ��� LF ¥A�

kª� «¬� 3d� Fig. 9� Ou�) �". ab/1 ³?ÔA�

7TcC �r �� J0�� TEOS ¥A� X3\G> 78ç 7�8

ç �H !� 7� �c�d abÔA> ÈA8ç R". !� +, �

�� LF ¥A1 J0! >ÔS ×)�ç �) -. LF P��

� ?�� ÈA�ç R U!". �h� 2. ab/ ³?ÔA �Í�

�� ?�ÈAu���� ab/ ³?ÔA1 7�� +, LF ¥A

� �� i*8ç ��KG� ab/ ³?ÔA� -~R� +, *}

8ç 7��: ¢!� �". ×'ÔA !X1 ab/ ³?ÔA���

?�ÈAuÄL � u���1 LF ¥A1 c�! M1 ×'8ç

����, �¸ ;L>�� úX{ c �". !e Û. úX. �c

�d abÔAXc� order of magnitude� 0.001 s−1E: �x{ �

�c�d1 abuÄ(reaction time=1/k1)[19]L ab/ ³?uÄ: í

îd �&{ c �� U!".�� ab/ ³?uÄ. 100ml1 TEOS

ab/: ³?8�ë j�� uÄ: 1k8� U!". ¤, ab/ ³?

ÔA� �:cC   ³?uÄ: ��� U!". ab/ ³?uÄ! a

buÄ¢" k"À ab�1 abÔA� ³?ÔA� 1ä8ç �H

a3= ��� abuÄ� 1ä8ç �� U!". +,� ab/ ³?

uÄ! abuÄ¢" �ç �� 10.0 ml/min !X1 ÔA��� ab

ÔA� abuÄ� 1ä8ç �H ! �� ?�ÈAuÄL � u��

�1 LF ¥A� �c�d/fg abÔAXc� 1d ;'R".

ab �r îaÔA� ?�ÈAu���1 LF ¥A� kª� «

¬� 34 �¸;L� Fig. 10� ��� �". ?�ÈAuÄ1 �¸;L

e Û! îaÔA� M1 «¬: Ù� ÷. U> ��K". !e Û.

;LA Z�� G>4 abuÄL õguÄ [19]L1 íî� 1d ¼�

{ c �". õguÄ(mixing time). rXab�� õgÔA� ab

ÔA� kª� «¬: �&8 Zd !��� ÉÊG>� �r���

ab/9! �\ ab: { c �AC ��c�1 õg'AT ��

��ë Õ�R". Fitchette Tarbell[20]� 18À õguÄ. îa�

1d �r� �?�� ÁñÖ1 1/3�c_� aíI8� UG> ú�8

¡". ø �¸�� ��R ab� [�J Rushton ab>� ! a

Fig. 8. Effect of water concentration on silica supersaturation at parti-cle induction point in sol precipitation. Other reaction condi-tions were fixed at 0.224 mol/l of TEOS reactant concentration,0.89 mol/l of ammonia concentration, 30 min of feeding time and900 rpm of agitation speed.

Fig. 9. Effect of feed flow rate of TEOS reactant solution on silicasupersaturation at particle induction point in sol precipitation.Other reaction conditions were fixed at 2.5 mol/l of water con-centration, 0.89 mol/l of ammonia concentration and 900 rpm ofagitation speed.

Fig. 10. Effect of agitation speed on silica supersaturation at particleinduction time in sol precipitation. Other reaction conditionswere fixed at 2.5 mol/l of water concentration, 0.89 mol/l ofammonia concentration, 30 min of feeding time and 0.224 mol/lof TEOS reactant solution.

HWAHAK KONGHAK Vol. 38, No. 6, December, 2000

824 ���������������� �

b��� îaÔA� +� Áñ�?Ö. Áñ�c(power number)T

!�d 6{ c �GH !� 34 ;L� !k U '��) �"[21].

! Áñ �?Ö: ÐlG> ø �¸��1 îaÔA 400-1,500 rpm �

!1 õguÄ. 0.2-0.73 s> #��". !e Û. õguÄ. ab

uÄ� íd �� �. UG> ?�ÈAe LF J0. abuÄ�

1d ;'m: w c �". +,� îaÔA� ?�ÈAe LF J

0� M1 «¬: ³� ÷¿: �&{ c �GH !� ?�ÈAuÄL

� u���1 LF ¥A1 �¸;Le U ת8¡".

TEOS>�� ��� ?� OP�� ̨ g0�� ?�1 D� ?

�ÈAuÄL �� (=4 ±T ��� �". KimL Kim[13]. ?

�ÈAu���1 LF ¥A� ̨ ?�1 DT ;'8�ë ��

<54 =�E: ÜM Ð �". !91 ;L� 18À ?�ÈAu��

�1 LF ¥A� +, Ìù t0�� ?�1 Éc� ;'�H �

!��� ab� 1d t0�� LF � 3�� ?�1 0�� Kí

�) &�#1 6J?�� ̨ g0R"� 8¡". +,� -. LF

¥A�� ?�� ÈAR ���� V. Éc1 ?�� t0�) Ì

¨\G> �. D1 ?�� g0��� a3> 2. LF �� ?

�� ¾¿ t0R ���� 2. Ãt0 ÔA> =8� \. Éc1

?�� t0�)   D1 ?�T ̨\G> Çç R". !e Û.

?�De ?�ÈAuÄL1 X±±T w~¢ Zd ø �¸1 ü

abP��� ?�ÈAuÄ� +� ̨ ��� ?�1 D� T �

�� ¢¶". Fig. 11�� ¢� Ðe Û! 2. ?� ÈAuÄ: �y

abP���� 600 nm1   ��� ?�� g0R aÀ ?�ÈAu

Ä! �. P���� 100 nm1 �. ?�� ̨\G> OP��".

!U. ?�ÈAu��� t0R ?�� 1d ̨?�1 D� ;'

�� �c!". !e Û. ;L� abP�� +� ?�ÈAu���

1 LF ¥A � e Áu� W±8� �x4"À fç ú�{ c

�� U!". ø �n� ¢�� ?�ÈAuÄL ?�De1 X±±

� ù ?� t0! ̨ ?�1 D� �� <58ç «¬: �

"� KimL Kim[13], Bogushe Zukoski[7, 8]1 ;LeA ת8�

U!".

5. � �

ø W6��� _ `�ab^G> TEOS>�� ��� ?�T g0

8� L'�� abP�� +� ��� ?�D1 � T �'8¡G

H !T ?�ÈAuÄL � u���1 LF ¥Ae X±±T h

d dÑ8¡". abP�! ?�ÈAuÄL LF ¥A� kª� «¬

: dÑ8 Z8� TEOS1 �c�d E fgab: 1Ë1 WÔ a

bG> ij8¡". TEOS ab/1 ¥A1 7�� �c�d1 ÔAT

7�u`H !> =8� �r �1 LF ¥AT Y� 7�uv Â.

uÄ �� ?�� ÈA��". ��� ?� ÈAu���1 LF ¥A

� TEOS ab/1 ¥A� 7� {cC YSx >�S *K8� UG

> ú���". !U. ?�ÈA� LF ¥A� 1ä8� U! ~�,

TEOS ab/ �1 �r P0 E P� ��A �(8ç «¬: Ù�

�¿: ûu8� U!". !e È�4 �¸;L� / ¥A � �A ±

���". / ¥A 7�� +, �c�d ÔA1 7�> =8� ?�È

AuÄ. Dç *K8¡GH ?�ÈAu���1 LF ¥A �4 Dç

*K8� UG> ��K". ab/ ³?ÔAA ?� ÈAuÄ E LF

¥A J0� V. «¬: ³�". TEOS �c�d/fgabÔA� íî

\ Dx � abuÄ: �y". +,� ab/ ³?ÔA� �� DX

���� ?�ÈAuÄ E LF ¥A� ³?ÔA� 1ä8¡G� ³?

ÔA� abuÄ¢" Y,R� +, ?�ÈAuÄ E LF ¥A� �

� o*8ç �8� U: w c ��". 4à, ?�ÈAuÄ E LF

¥A� ab �1 îaÔA�� M1 «¬: Ù� ÷. UG> ��

K". !U. ø �¸�� ­4 îaÔA Z ��� ab/ õguÄ

! TEOS abuÄ� íd �� � �c� ?�ÈA E LF ¥A

J0! 3�� TEOS abÔA� 1d ;'� �c!".

abP�G>�� ̨ t0�� ?�1 DT ú�d ¢ Zd ?

�ÈAuÄ� +� �c�d E fgab ÔAXce ̨?�De1

X±±T 6d ¢¶". ! ;L9. abÔAXce ?� D� ?

�ÈAuÄL ×±\= X±±T ��� �¿: Ou8¡GH !9

±� KimL Kim[13], Bogushe Zukoski[7, 8] �! Ou4 ?�t

0 E D� 34 ;LeA ת8� U!". ø W6� ü abP�

� +, íî\ pfç �'{ c �� ?�ÈAuÄ: 64"À !>

�� _ `�£'1 <54 kinetic �c= �c�d/fg ab1 ÔA

Xc9L ̨\G> Ç)�� ?� DT ú�{ c �"� U: O

u8¡".

ø W6� 4qL��&1 '99 Q'ùW6í1 �I: Ù~ c­4

W6?�"(1999-2-207-008-3).

����

k1 : reaction rate constant of hydrolysis

k2 : reaction rate constant of condensation

Q : feed flow rate

tF : feeding time(V0/Q)

tI : particle induction time

Vo : initial reactor volume

����

1. Kim, H. S. and Kim, Y. J.: Journal of Korean Association of Crys-

tal Growth, 1, 1(1991)�

Fig. 11. Correlation of mean particle size of silica with particle induc-tion time within variation ranges of reaction conditions appliedin this study.

���� �38� �6� 2000� 12�

TEOS� Sol � ���� ����� �� 825

w

Pub-

i-

2� Bradley, D. C.: “Metal Alkoxide,” Academic Press, London(1978).

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HWAHAK KONGHAK Vol. 38, No. 6, December, 2000


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