
J. Jpn. Soc. Soil Phys.
q©ª«
No. +*-, p. ,- -* ,**0   
*ῌ *ῌ

*Critical Flocculation Concentration of Montmorillonite, Beidelite, Illite
and their Mixed Suspensions
Machiko SUZUKI*, Taku NISHIMURA* and Makoto KATO** United Graduate School, Tokyo University of Agriculture and Technology,
Saiwaicho, Fuchu +2-ῌ2/*3, Tokyo Japan
Abstract
Little is known about colloidal properties of beidelite, a member of smectite group.
colloidal behavior of mixed-clay suspension is not wholly clear.

Also,

In this study, critical ﬂoccula-tion concentration (CFC) of Na-saturated montmorillonite, beidellite and illite suspension, and of
mixtures between of them was measured.

Na-saturated clay minerals having diameter smaller

than , mm were mixed with NaCl solution to prepare di#erent electrolyte concentration. Flocculation of these suspensions was detected by transmission of 1** nm wave length light. CFCs ofmontmorillonite, beidellite and illite were *.*,, *.**/ῌ*.*+, and *.*+,/ῌ*.*,/ mol L +, respectively,
depending on clay concentration of *.- to *.+ kg m -.

CFCs of the mixed clay suspension were

smaller than the greater CFC of the either single clay suspension.

Observation of ﬂocs and x-ray

di#raction pattern suggested that binding between di#erent clay minerals occurred in the processof ﬂocculation.
Key words : Flocculation, Critical Flocculation Concentration, Montmorillonite, Beidellite, Illite+    al., '+322,  pq$ + kg m - : pH $ 3.2 
Na lmn$ NaCl  *.*.. mol L + :yzi&~VWcd- ?xpqCBA

!"#$%& '()ῌ*+ +32.,- cd] XvyztuaUbi&~pq./0 123456789:;<a + kg m - i&~acAB&- d $=>?@AB&- !"#CBA DEF$G

x '+332,  Na lmnXvyza

HB$ IJK:LM 'Egashira and Otsubo, +32-,

Ubc pq *.+- kg m - lmn$ pH+* : *.*+

4NOPQRST&UM 'Nishimura et al., ,**+,

*.*- mol L +  NaCl :yzcd~VW$VW?@AB&- Chatterjee et al., '+333,  XY

cAB&- ῌo '+330,  pq - kg m - :Z[\!"#]^_`aUbcd$ !"pH+*  Na  *.*+, mol L + #ef\ghi&jkcABHB- NaCl :yztuH&~VWcd- Oster et al.,lmnopqrstu$Xvtuwxyztu'+32*,  Na lmn CFC  pq{|}i&~ga  yz 'Critical *./- kg m -  *.*+, mol L + Hd~cA

Flocculation Concentration, CFC, ~- Keren etB&-*  ¡*[*[¢ £+2-ῌ2/*3 ¤¥o¦§¨ -ῌ/ῌ2 : Xv yz  yz  !"# #



24

 Oster et al., +32*  Na 
CFC   + kg m -  , kg m *.*// mol L+R Li 45 

 Arora and Cole-man +313  Na  2.- L +?, b +*- ¼ ,**0

X 67 @RXR 

8 K 45 Mg 45[

@ X 67%

XR X 67 PQ < =<S24
hU f7R

CFC  pH  1 !" *.**3 mol L +  *.+2/ mol_&9  > @ &>#$%  Goldberg and Forster

7, DLVO ?@ AB Keren et al.,+33*  Na    +* kg m +322 ; Hsu and Liu, +332 Keren et al., +322 S

pH  1  1.0 & CFC  *.*3 mol L + +332 *.+. mol L + 

$%

*.+- kg m -  + kg m -  DLVO ?@C\D=-'( )*+,& , : + -.

CFC

 / Na 010234  Na 

5

6 7 

CFC  CFC ' 

%89 :;< =)*)* Na 010234 

Y  $% ))*  *.+ kg m - *.+/ kg m - *., kg m - *.- kg m  %C 

.

%89



CFC

7> ? @A  . 8B

g% ,   *.- kg m -@ACῌ:;< =7$ 

DE ?FG3HI10J
C:;%KL +332  G3HI1


0J

1 M



  CFCJ

% +*῍ 89 G3HI
@R G3HI1:%M,Na -

^?

b

CFC _`a@RZ[CFC _>7R$%

%¡EF Cancela[G +/¢,* g %1£¤HG 3** mL

89 I¥; @\ d¦ , mm

¡ >%§¨



 " #$cSde1c7f%%#$

et al., +330 ; Olejnic et al., +31++%VW%X YZ[ @\!
]

+ : + 89&9 M *., kg m - *.-, 6- :;VW%XR

kg m -;S>7$%TU
Frenkel et al., +33,  F?

9

89:;VW%$7R   

N% O PQ 0% +*῍ #D$, 6-   % + : , , : + + : +

'
7

©J

,

¡ >%§¨, $ E, mm

% . ª\K G +, kg m -

 %

L

  , : + -. %89&9 C:-   " !] %¨\M>,  

;f @A 'g%h()*Xi7 O « +*/¬  , ­#O«  ®¯ ,. ))* 010234    N%*"jk89 

l3m+,n%Kb :; =h(, .** mL-../῍+** mL %#D89­PQ °RU7±S °RU&9
E%°RU7>7ª\K-.

²TU³%VM

Na 45,



H,O, N%M´«.µn + mol L +NaCl N % 



7@A

#DE%9¶ - ª\K,+ 

010234  jk  - 6-/  1£¤H%#D²TU%o[p qrs./tVM , : + -.

« 2*῍ e·N 010234

u%M´E% +*¢+/ ª\K O*.+, L%#D ,. ­CY¸_dvwG F dvxyz{ % jkVM %M´ Y  1£¤HWX

 USA G|}~ [ %   USA

E% AgNO- N %%#VM Y7>

014~j [ % $ 0

7ª\K=G

Project Z[

2 Source Clay12  d 3 -Y010234 jk  Mg 45[@ X 6789

, 8 Lim and Jackson +320:;,,,¹,¹+ :;VW:;VW ºº¶ UVmini-+,.* Z[\ % 5]^= º

º _<`º »º%+,

_<`%a]

» :  !$ 4 56 !$ῐ ῎lnῌ
῍
῏
+**

ῌ


῍ *.*/ kg m- *.- kg m- 
 !"#$ %&' .** nm ()*+,-./01 232$ 4 56!$

6 !K7e?9:"¼

25- 
-+ 

 CFC

 !"$ 4 56 !"$!" CFC @ Table , §1

6



¨' *.*/ O/0( NaCl @ CFC K201


! CFC #$ P?© *.*,

6 !7289:"#$ %&'mol L+ -./01 4 56 ! CFC #$ '1** nm ()*;+-./01 70<$ =>-#*.+ kg m- Kª *.*+ mol L+ -$ *.+/ kg m- *.- kg%&' 1** nm 3?@AB201m- -#©e* *.**/ mol L+ -.«$ ¬ 20 -"CB#DEFG-H/01­®¯°-)*2±§²³@201+-* mL I>J NaCl "KLI"@M

BN$ OPQRS01.?3T< NaCl KUVWXYZ@[\20]^@_`$

6 !#$ 'bO´e82±§O
²³@201 Oster et al., +32* µ¶-#$ 

6 !$ 4 56 !$ 9:a:#$' + kg m- K , kg m- ($ Na

6 ! CFC#$ Y·?©B *.*// mol L+ -./0-* mL I>J"@ ,/ mL Ibc +... cm

de8=>201 f0$  *.- kg m- 

Table +

 !g -* mL Ibc +1.. cm -=>201,

hijklm%nop-q$ r3? . cm

Speciﬁc
ChargeCEC
SurfaceDensity¸molc kg+¹ ¸m, +
g ¹ ¸molc m,¹s - . mL tr2$ @CB201-

 - (u$ vwtr2$ @CB2

01 f0$ Ux'yT0a:#$ IUVWX@z<
01 UVWX#$ I>J{|}3?UVWX{f~KI>JX3?{g}nWX@
2$ .?3T<z<0I>JWX3?7e@2

Properties of clay minerals

Montmorillonite
IlliteBeidellite*4120**4+0-**4//-*+4,/0º+*0,41+1º+*0+4,*,º+*/

0,0
0*
.0

* pH of montmorillonite, illite and beidelite for CEC
measurement was /.1, 0.* and /.2, respectively.

KP/8z<01"3? ῌ @@2$  ῍ @ 8
=>(

8
Table ,

201! pH # /.2$

6

!K4 56 ! pH # /./ -./01
,,,

X 

X  #$ Rigaku RAD-, k@ 01 Cu-Ka

@J -* kV$ J

+* mA - 201 9:"' CFC @20(I@I>

$ 

"{g}KUx20"n8t2$

CFC of NaCl for single clay suspensions

CFC
Clay
concentration Montmorillonite Beidellite
Illite¸kg m-¹¸mol L+¹¸mol L+¹ ¸mol L+¹
*4+
*4+/
*4,
*4-

*4*,
*4*,
*4*,
*4*,

*4*+
*4**/
*4**/
*4**/

*4*,/
*4*+/
*4*+/
*4*+,/

7ff20 X @H$ CFC I X ]^K201,,-  K¡X   CEC #$ Ca c¢0I@ NH.£ - 2$

ce0 Ca @¤¥ 

P/8CB201 Ca c¢0( !$6 !$ 4 56 ! pH #7e¦e /.1$ 0.*$ /.2-./01 f0$ ¡X#$ EGME P/8z<
01 Table + 1

Table -

CFC of NaCl for mixed clay suspensions(mol/L) (M : montmorillonite, I : illite, andB : beidelite)

Clay
concentration

Mixing
ratio

M:I

M:B

B:I

*4, kg m-

+:+

*4*+/

*4*+

*4**1/*4- kg m-

,:+
+:+
+:,

*4*+/
*4*+,/*4*+,/

*4*+
*4*+
*4*+

*4**/
*4**1/*4**1/

xyz{ | +*- } L,**0N

26

  



0234< BDBC(=>=?@ABC !"#9(j 

$ %&' CFC  ()*+,-, 

 CFC-.,.+ /01 + : + 

234

Table -  , 56

7/08



 - /0()*+,- BDBChi(e CFC 

234



CFC kl =>=?@ABC(BDBC7/08 G0I
9 CFC 7:8- ;<=>=?@ABC7 M BDBC7 I EB

FDBC7 B (8:8 -Q =>=?@ABC(EBFDBC7 + : + /08
G0=>=?@ABC(BDBC7 + : + /08 G0 *., kg mH- *.- kg mH- 9BDBCI
CFC (J7:8 - K,=>=?@ABC CFCLM*.*, mol LH+N O$P

XY8 efg8

 *., kg mH- *.- kg mH- 234 CFC m,P *.*+ mol LH+  =>=?@ABC(EBF
DBC CFC <nJ7:8 EBFDBC(BDBC7 + : + /08

G0



 *., kg mH- *.- kg mH- 234 CFC  m,*.*+,/ mol LH+ ( *.*+/ mol LH+ 9 =>=?@ABCP *.**1/ mol LH+  EBFDBC(BDBC CFC

I234RSTUQ$ VW BDBCXY

<nJ7:8 BDBChi

JQ

- NaClXY8 ZTUQ ()*+,- XY9/0234[

NaCl\I]^_`aJbRcd 8  /7tu BDBCvῌs&0wK$

Fig. +

XY8 - BDBC opqrs

Tactoids of ﬂocculated clay suspensions (clay concentration is *.- kg m-, NaCl concentrationis the corresponding CFC. Arrow in the photographs shows tactoids in the suspension ).
A : montmorillonite, B : beidellite, C : + : + mixture of montmorillonite and beidellite, D : , : +mixture of montmorillonite and beidellite¦§ : =>=?@A !"  234¨©56

27

  Oster etr,#vw /.-/ mmxyz , mm H+ Fig. +-A

al., +32*     !"!", _`aef {'-+  # $%& '(   Fig. +-B  =>=?@A !")*'+,' -: + : , 



0156

*.- kg m7-

1234:

'%& 89/0 CFC :;9<* =>=?@A: Table -: + : , 

234 =>=?@A: + : + + : , , : +  234NCD-.,., / + : , , : + 01234 CFC_`aef {'-+=>=?@A!": + : + B | _`aef pqr Fig. +-B CFC , + : +  B CD *.- kg m7-

C |_`a, _`a ef }~ CFC E*.*+,/ mol L7+K, Nr #vwr -.. mmxyz *.21

CFGH+

 , : +  BI CFC( =>=?@A,J' CFC KLG:< 

mm stdH+ [_`a:ef

=>=?@A !", 7:F N qr=>=?@A !": + : , , : + B CFC ,!"

7+

B

B !

..+ mmxyz + mm stdH+ pq-=

CFGH( !",>=?@A0156  | _`a u$, : + 

'+

ef!": , : + 

H+MN *.*+ mol L: , : + " CFC=>=?@A_`a Fig. +-D , #vwr

'  { Fig. +A, C, D  =>=B:O$ *

?@A  B,:* _`a    !"=>=?@A, CFC PQ     ' _`a,9 '( -- 

  RST56
*

CFC PU '  VW :N_`a

''+ X  van Olphen, +30- Quirk, 01234 ef _`a, =>=?

and Aylmore +31+ , Y Z[=>=?@A@AI:234 ef _`a J'



#\

]^

_`a Tactoidd:ef*gh ijkbc

T: :<   *'X _`alK=>=?@AVW !"VWL N =>=?@AYmno_`a
ef pqr mnY_`a,st[u$Fig. ,

- H+N

 ,

 Al ¡d¢ C£¤¥ H=>=?@A

Sedimentation volume of clay suspensions(M : montmorillonite, I : illite, and B : beidelite. Numbers in the ﬁgure
denote ratio of clay minerals. Clay concentration is *.- kg m -)

9  +*-  O,**0P

28

 Si  !"#"$%&
 ' ()*+,!)-./01
2!34567-ῌ. ΐ῎ῒ῏89:;<=>?@ABC Fig. , DE
F7 "#"$%& 0 GHIJ/')K+LMN
Na Q#LRSTU/')V

ONorrish, +3/.P*E WXY >?@)*+N1ZF!34567"#"$%& ! [F0  C:;EF\; >?@)]^N1ZF7 [F  ! C:;EF\;0 W6_6`-\;*+1>?@CDEF OFig. ,P7 :;GHI
CFC XYab !C:;

EFGHI/0 c῔X;)deFFfghELM
N1Zb!=3iCEF7 ,60c῔X;

ZbjklmnopqCrsEFXY >?@)*Fig. -

X-ray di#raction patterns of montmorillonite, illite and their mixture. (clay concentration is *.- kg m-)ῌ montmorillonite
῍ illite῎ supernatant of + : + mixed clay suspension
῏ sediment of + : + mixed clay suspension

Fig. .

X-ray di#raction patterns of beidellite, illite
and their mixture (clay concentration is *.kg m-)ῐ beidellite
ῑ illiteῒ supernatant of + : + mixed clay suspension
ΐ sediment of + : + mixed clay suspension+N1ZF!34!>?@AB! -tM7
X ῑ῍ῐ

-ῌ/

"#"$%&!

C + : + /:;EF\;Suvw!>xI WEb:;My"#"$%&


W6_6GHI X z{|XYC

Fig. - DEF7 }v89vw X z{|XYC~

! "#"$%&nm

{|k0 +.- nm *.0.

*.-, nm /ZF7  {|k0+.*/

nm *./+ nm *.-- nm /ZF7 ,650C:;E

FvwSuvw>xIk!-tEF OFig.
-P7



!

C + : + /:;EF\;S

uvw >xI WEb:;My
W6_6GHI X z{|XYC Fig. . D

EF7  {|k0*.1/ nm*.-0 nm/ZF7 ,650C:;EFvwSuvw
>xIk!-tEF OFig. .P7
X z{|/0 "#"$%&῔῔

 6:;GHIab >x89)[6bF,!)52/7`-89/0ghE1 NaCl abg
h>xEF>x >xE10 89)[6ba,,!2589'/X;)+bF,!)D^67 ,XY0 gh/ "#"$%&

/0ghE1 NaCl ab  O"#"$%& !

EN0

 P 89)MGHI/0gh)deF
XY! -tEb7

%& : %&%'()  

A. (+333) : A DFT study pm clay-cation-water in- 

teraction in montmorillonite and beidellite, Com-

CFC  

putation Materials Science, +. : ++3ῌ+,..

CFC

Egashira, K. and Otsubo, M. (+32-) : Swelling and min-!"#$eralogy of smectites in paddy soils derived from%&%'()







*, : ++

marine alluvium, Japan, Geoderma, ,3 (,) : ++3ῌ,-./ 0 12 345 "#6789:;#$

  %&%'() <= CFC 2>4 #%&%'()
267;=/. @AB;#2

 ?

 

/. @AB; C"#$%&%'()   DE  , : + CFC 2OPNQ

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