Adsorption of surfactants on sediments

Chemospher~, Vol.13, No.2, pp 293-300, P r i n t e d in Great B r i t a i n

1984

0 0 4 5 - 6 5 3 5 / 8 4 $3.00 + .OO © 1 9 8 4 P e r g a m o n Press Ltd.

A D S O R P T I O N OF S U R F A C T A N T S ON S E D I M E N T S

K.Uran~, M . S a i t o and C . M u r a t a D e p a r t m e n t of Safety and E n v i r o n m e n t a l Engineering, Y o k o h a m a N a t i o n a l University, 156 Tokiwadai,

Hodogaya-ku,

Yokohama,

240 Japan

ABSTRACT A d s o r p t i o n isotherms of 5 p r i o r i t y surfactants on 7 river sediments were obtained. The surfactants w e r e ready to adsorb in the same order as the adsorption on m i c r o b i o l o g i e s . The a d s o r b e d amounts per gram of the organic carbon in the sediments were n e a r l y equal for m o s t of the sediments.

INTRODUCTION Surfactants uses,

are a b u n d a n t l y used for wide range of industrial and d o m e s t i c

and they are d i s c h a r g e d into wastewater.

The w a s t e w a t e r contaminates

w a t e r e n v i r o n m e n t and causes various troubles e s p e c i a l l y in the areas w h e r e any sewage t r e a t m e n t systems have not been provided.

The surfactants in the

w a t e r e n v i r o n m e n t may be a d s o r b e d on s e d i m e n t and m i c r o b i o l o g i e s biodegradated.

and may be

The a d s o r p t i o n of s u r f a c t a n t s on m i c r o b i o l o g i e s was r e p o r t e d

in the p r e v i o u s paper I, and the b i o d e g r a d a t i o n of surfactants will be also r e p o r t e d in the s u b s e q u e n t paper 2.

In this study,

a d s o r p t i o n isotherms of 5

p r i o r i t y s u r f a c t a n t s on river sediments were o b t a i n e d and d i s c u s s e d for pres u m p t i o n of the fate of surfactants

in w a t e r environment.

EXPERIMENTAL Three anionic and two n o n i o n i c synthetic surfactants w h i c h are shown in Table 1 were used in this study,

The a b b r e v i a t i o n for each s u r f a c t a n t as

shown in Table 1 is used in the following figures and tables. S e d i m e n t s w e r e sampled from seven points on four rivers; M i z u s a w a River, K o a y u River,

Sagami River,

and Hirase River,

in K a n a g a w a p r e f e c t u r e of Japan.

The values of BOD and MBAS of the river w a t e r at these s a m p l i n g points are shown in Table 2. because

Those values show that M i z u s a w a River is very clear

it is a m o u n t a i n varey, but Hirase River is much c o n t a m i n a t e d because

it is an urban river in the area where no sewage treatment systems are provided.

293

294

Table 1 Abbreviation

Name

Surfactant Samples Molecular formula*

LAS

n-alkylbenzenesulfonate

CI2H25C6H4SO3Na

AES

polyoxyethylene

CI2H250(CH2CH20) 5SO3Na

AOS

e-olefinsulfonate

CI2H23SO3Na

AE

polyoxyethylene

alkylether

C6HI30(CH2CH20) 6H

APE

polyoxyethylene

alkylphenylether

C9HI9C6H40(CH2CH20) I0

alkylsulfate

*Numbers of carbon in alkyl and olefine groups and of oxyethyoene group are mean values. Table 2

Water Qualities of Sediment Sampling Points

Sediment

River

BOD(mg/l)

MBAS(mg/I)

A

Mizusawa

0.8

0.0

B

Koayu

7.3

0.4

C

Sagami

1.2

0.1

D

Sagami

1.4

0.i

E

Hirase

15.4

1.0

F

Hirase

29.7

2.2

G

Hirase

24.1

1.8

Table 3

Properties of Sediment Samples

Sediment

Ignition loss(%)

Organic carbon(%)

A

4.8

0.7

B

3.6

C

4.3

Humic substance(%)

Caption-exchange capacity(meq/g)

Surface area(m2/g)

0.i

0.i0

68

1.3

0.i

0.31

39

1.7

0.2

0.27

35 49

D

2.5

1.4

0.i

0.13

E

7.4

6.0

1.4

0.13

32

F

5.2

3.8

2.5

0.07

25

G

2.8

2.5

0.6

0.07

20

Furnace

ICatalysisI

Recorder t IR CO2 Analyzer

Soda l i m e < i r Trap Fig,l Apparatusfor measurementof organic carbon contentof sediment.

295

The p r o p e r t i e s of those sediments were m e a s u r e d after drying at ll0°C for 2 hours,

and are shown in Table 3.

ing at 600°C in air for 2 hours.

The ignition losses were o b t a i n e d by heatThe organic carbon contents w e r e o b t a i n e d by

the following m e t h o d w i t h an a p p a r a t u s shown in Figure i.

The dried sediment

sample of 500 mg was put into a furnance and was heated at 800°C in 400 m l / m i n air flow removed carbon dioxide. c o m b a s t i o n Of organic substances gas analyzer,

The carbon dioxide w h i c h formed w i t h the in the s e d i m e n t was d e t e r m i n e d by a infrared

and the o r g a n i c carbon content of the sediment was calculated.

The contents of humic substances were o b t a i n e d the following method.

The dried

500 mg sample was e x t r a c t e d with 50 ml of 0.5 wt% sodium h y d r o x i d e solution at 100°C for 30 min.

The c o n c e n t r a t i o n of humic substances in this solution was

a n a l y z e d from the c o n c e n t r a t i o n of TOC after n e u t r a l i z a t i o n by c o m p a r i n g w i t h a s o l u t i o n of a r e a g e n t humic acid substances was calculated. following method.

(Wako C h e m i c a l Co.),

and the content of humic

The c a t i o n - e x c h a n g e capacities were o b t a i n e d by the

The dried 1.00g sample was packed in a column.

Ammonium

acetate solution was p e r m e a t e d in this column and the ligands of the sediment w e r e c o m p l e t e l y e x c h a n g e d to a m m o n i u m type.

Nextly,

the a m m o n i u m was e x c h a n g e d

and eluted by the flow of i0 wt% sodium chloride solution,

and its concentra-

tion was d e t e r m i n e d by a colorimetry.

capacity was calcu-

The c a t i o n - e x c h a n g e

lated from the amount of eluted a m m o n i u m ion.

The surface areas were o b t a i n e d

by a m e t h o d 3 from a d s o r p t i o n isotherms of the m e t h a n o l vapor. The a d s o r p t i o n isoterms of the surfactants were o b t a i n e d by a b a t c h w i s e a d s o r p t i o n method.

One h u n d r e d m i l l i l i t e r s of aqueous solutions ranging from 5

to 40 mg/l of the s u r f a c t a n t s were shaken w i t h 1.0g s t o p p e r e d 300 ml flasks at 25±0.5°C in the all tests.

for 24 hours.

of the dried sediments in The pH values w e r e 7.0±0.5

The c o n c e n t r a t i o n s of the surfactants were a n a l y z e d after

f i l t r a t i o n of the sediments.

The c o n c e n t r a t i o n s of the anionic surfactants were

d e t e r m i n e d by a c o l o r i m e t r y of the complex w i t h m e t h y l e n e blue,

and those of the

n o n i o n i c s u r f a c t a n t s were d e t e r m i n e d by a colorimetry of the complex w i t h ammonium t e t r a t h i o c y a n o c o b a l t a t e .

These c o n c e n t r a t i o n s were c o r r e c t e d by the b l a n k

tests for d i s t l l e d w a t e r w i t h a d d i t i o n of the sediment.

RESULTS AND D I S C U S S I O N A d s o r p t i o n of A n i o n i c S u r f a c t a n t s The a d s o r p t i o n isotherms of LAS on the various sediments are shown in Figures 2 and 3 as the F r e n d l i c h expression,

logarithmic r e l a t i o n s h i p b e t w e e n

the a d s o r b e d amount per gram of the dry s e d i m e n t Q(mg/g-Sed.) c o n c e n t r a i t o n C(mg/l).

and the e q u i l i b r i u m

Since the r e l a t i o n s h i p s g e n e r a l l y show linearity,

a d s o r p t i o n isotherms can be e x p r e s s e d by the F r e u n d l i c h equation, The values of k and n are s u m m a r i z e d in Table 4. except

the

Q = kC I/n.

The values of n are i.i~0.i

for S e d i m e n t A and the values of k are in the range from 0.025 to 0.091

296

except for S e d i m e n t A. sawa River,

S e d i m e n t A was sampled from a very clear river, Mizu-

and its o r g a n i c carbon content was only 0.7% though its surface

area was m u x i m u m in the sediments employed.

Therefore,

the a d s o r p t i o n abili-

ties of the sediments seemed to be i n d e p e n d e n t of the surface area and to be r e l a t e d with the organic carbon contents,

X(g-carbon/g-sediment).

The

r e l a t i o n s b e t w e e n the values of k and the values of X are p l o t t e d in Figure 4.

Since the r e l a t i o n s h i p s

shows a p p r o x i m a t e l y

linearity,

the logarithmic

r e l a t i o n s h i p s b e t w e e n the a d s o r b e d amount per gram of the organic the s e d i m e n t Qo~mg/g-O.C.) nearly e q u a l

each

carbon in

and the e q u i l i b r i u m c o n c e n t r a t i o n C (mg/l)

are

other for the various sediments as shown in Figure 5.

The

a d s o r p t i o n isotherms on the inorganic c o m p o n e n t s of the sediments were obtained by the ignition residues of the sediments, Figure 6. each

and the results are shown in

The a d s o r p t i o n isotherms for the various sediments are nearly equal

other,

and the values of k and n were c a l c u l a t e d to be 0.012 and 0.8,

respectively.

The value of n is slightly smaller,

and the value of k is much

smaller than the values for the sediments except S e d i m e n t A, and they are nearly equal to the values for S e d i m e n t A whose organic carbon content was very small.

Therefore,

the a d s o r p t i o n on the inorganic components can be

n e g l e c t for the general sediments w h i c h contain organic carbon more than 1%. Consequently,

the a d s o r p t i o n isotherms of LAS on the general sediment are

d e t e r m i n e d by the carbon contents of the sediments and are shown by an equation, Q = Qoc X = kocXCl/n = 1.9 X C I/I'I

Several reports showed that the

a d s o r p t i o n of c h e m i c a l s on sediments or soils were d e t e r m i n e d by the carbon contents of the sediments or the soils.

For an example, K a r i c k h o f f et al 3

r e p o r t e d that the a d s o r p t i o n s of pyrene and m e t h o x y c h l o r on sediments were d e t e r m i n e d by the o r g a n i c contents in the sediments. substances

Since m o s t organic

in the sediments may be humic substances and m i c r o b i o l o g i e s ,

the

a d s o r p t i o n on the r e a g e n t humic acid was tested, and the results are shown in Figure 7 as the logarithmic r e l a t i o n s h i p b e t w e e n Qoc and C. and n are 0.27 and I.i, respectively. for the o r g a n i c m a t t e r s

The values of koc

The value of n is equal to the values

in the sediments, but the value of koc is much smaller

than the values for the sediments.

Further,

the contents of humic substances

in the sediments were smaller than 2.5% as shown in Table 3.

Therefore,

it is

obvious that the a d s o r p t i o n on the sediments is not m a i n l y on the humic s u b s t a n c e s in the sediments, the sediments.

and is expected to be on the m i c r o b i o l o g i e s

in

The values of n for the a d s o r p t i o n on the sediments is nearly

equal to the values for the a d s o r p t i o n on the m i c r o b i o l o g i e s r e p o r t e d in the 1 previous paper . The a d s o r p t i o n isotherms

for AES and AOS are shown as the logarithmic

r e l a t i o n s h i p s b e t w e e n Qoc and C in Figures linearity and are nearly equal

each

8 and 9.

These r e l a t i o n s h i p s

other for the various sediments,

show

297

//

o s0~,.,..< A A Sediment 8

I,C

5,(i

~f// /////6 // /z6 / /

o Sediment C • Sediment 1]

A Sediment E • Sediment F "o. Sediment G

/

1.(

~0.1

0.05 ,.

,

,

,

,

,

,

I i l

lO 100 10 100 C (rag/l) C (mg/[) Fig.2 Adsorption Isotherms of I_AS on various sediments ( I ) . Fig.3 Adsorption Isotherms of LAS on various sediments ( I I ) . O.IC

Table 4 V a l u e s of k and n of LAS for Various Sediments Sediment

k

n

A

0.006

0.7

B

0.025

i.i

C

0.030

1.0

D

0.039

1.0

E

0.091

1.2

F

0.048

i.i

G

0.050

1.0

A

.= 0.05

0

'

~

~

J 0.10

X (g-cn rbon/g-sedlment) Fig,4 Plots of values of k vs organic contents of sediment. (Symbols In Flgs.~-6 and 8-11 are some as in Figs,2 on{} ) )

2.0

lO0 25°C

250£

. Q ~ 1,6

!k b

o~"

.X. °

%

, . / N

~io

~:

U

0,1

/A

,-..

. . . . ,, 10

,

,

,, ,.,, 100

1,05

I

..

10

I

I

I

i

100

C (rag/l) C (n~/]) Fig.5 Logor|thmlc re]utl~lshlps between goc and C for LAS. Fig,6 Adsorption Isotherms or LAS ol] Inorganic cowonents of sediment.

298

except Sediment

D.

Namely,

determined

by the c o n t e n t s

adsorption

isotherms

equations,

respectively.

the a d s o r p t i o n s of o r g a n i c

for AES

and AOS

of AES

substances

and AOS on the sediments

in the sediments,

can a p p r o x i m a t e l y

are

and the

be shown by the

following

O = I.i X C I/I'I

Q = "0.65 X C I / I ' I The values

of k

for the a n i o n i c microbiologies

and n are s u m m a r i z e d in Table 5. All the values of n, i.i, oc s u r f a c t a n t s are equal to the values for the a d s o r p t i o n on 1 r e p o r t e d in the p r e v i o u s p a p e r . F u r t h e r m o r e , the ratios of k

for the s e d i m e n t s surfactants.

to k for the m i c r o b i o l o g i e s

Therefore,

surfactants

on the

it is r e a s o n a b l e

sediments

are m a i n l y

are 0.52

oc for the all anionic

0.04

that the a d s o r p t i o n s

the a d s o r p t i o n s

of anionic

on the m i c r o b i o l o g i e s

in the sediments.

Adsorption The

of N o n i o n i c

adsorption

isotherms

as the l o g a r i t h m i c relationships sediments,

for the n o n i o n i c

relationships

show

except

Surfactants

linearity Sediment

between

and are n e a r l y

D.

Namely,

and APE on m o s t of the s e d i m e n t s substances

in the

approximately

sediments,

surfactants,

equal

it is shown

each o t h e r

following

The

for the various

by the contents

isotherms

equations,

are shown

10 and ii.

that the a d s o r p t i o n s

are also d e t e r m i n e d

and the a d s o r p t i o n

be shown by the

AE and APE,

Qoc and C in Figures

of AE

of o r g a n i c

for AE and APE

can

respectively.

Q = 12 X C I/1"4 Q = 6.1 X C I/1"4 The values

of k

Karickhoff

and n are also shown in T a b l e 5. oc et al 3 r e p o r t e d that the values of n for a d s o r p t i o n

and m e t h o x y c h l o r the p a r t i t i o n ties

were

approximately

coefficients

in water,

S.

Brown

between

and d i n i t r o a n i l i n e s ,

al 5 r e p o r t e d following

equation,

values

were

following

nonionic

surfactants

biologies, are 0.54

order;

of k

respectively

for the a n i o n i c

Further,

Therefore,

Brown's

could not be o b t a i n e d

The values

of n,

for the a d s o r p t i o n

for the sediments

oc for AE and APE.

surfactants.

Chiou

k oc of et

equation

However,

of koc for the tested p r i o r i t y

to the values

between

of the d e r i v a t i v e s

- 0.628 log S.

AE>APE>LAS>AES>AOS.

are equal

and the ratios

and 0.55

the ratios

log koc = 4.63

The values

the solubili-

P and k could be shown by the

of P or S for the s u r f a c t a n t s

formation.

related w i t h

equation

log koc = 0.937 log P-0.06. between

of p y r e n e

were

oc P, or with

the f o l l o w i n g

log P = 5.00 - 0.670 log S.

as follows;

the m i c e l l e in the

and octanol,

of k

and of the a d s o r p t i o n s

that the r e l a t i o n s h i p s

can be r e w r i g h t e d a cc u r a t e

water

and F l a g g 4 p r o p o s e d

and P from the data of K a r i c k h o f f triazines

1.0 and the v a l u e s

the

because

of

surfactants 1.4,

for the

on m i c r o -

to k for the m i c r o b i o l o g i e s

The ratios

Consequently,

are nearly

equal

it is r e a s o n a b l e

to

that the

299

50

100

./

25°C 25

"2 0 .

~. °

m / ~m

1{

v (3

o~

u

1.0 0.5

i

t

I

I I

10

1,0 C

•

]00

(lllg/l)

Flg.7 Adsorption lsotherlllS of LAS on hUllllC flcld.

]

i

I

I

p

IIIII

t

I

I

t

I

tl

lO

5O

25°C

•

•

/

lO0

C (mgll) Flg.8 Logdrlthmlc relationships between Qoc ond C for AES. 50O 25°C

•

"2.

u

c~ I00 •

D

g •

"1

I

I

l

I

i I I|

]

I0

I

I

I

I

I

lO0

l

I

D

I

I

I

l

111

I

I

|

I

I

I |]

[0 |o0 C (mg/I) Fig,9 Logcirlthmlc relcltlonshJps between Qoc ond C for AOS, Flg.]O Logarithmic relationships between 0oc Grid C for AE 500 25°C Table 5 Values of k oe and n for Various Surfactants C

(lllg/l)

•• •u

oJv ~ lOC

Surfactant D

LAS AES AOS AE APE l(

~

"i"

I

IIIII

~

lO

I

I

I

I

I

ti

I00

C (mg/l) Flg,ll Logorlthmlc relotlonshlps between floc ond C for APE,

k oe 1.9 i.i 0.65 12 6.1

n i.i i.i i.i 1.4 1.4

300

adsorptions

of not only anionic surfactants

the sediments Therefore,

are mainly the adsorptions

it is predicted

but also

on the microbiologies

that the adsorptions

sediments may also be the adsorptions

nonionio surfaotants

in the sediments

of many other chemicals on the

of the microbiologies

in the sediments.

REFERENCES i. K.Urano and M.Saito,

Chemosphere,

in contributing.

2. K.Urano and M.Saito,

Chemosphere,

in contributing.

3. S.W.Karickhoff, 4. D.S.Brown 5. C.T.Chiou, Technol.

D.S.Brown,

and E.W.Flagg, V.H.Freed,

ii, 475

and T.A.Scott,

J.Environ.

D.W.Schmedding,

(Received in Germany 29 November

Water Research, 13, 241

Qual. 10, 382

(1977) 1983)

on

(1979)

(1981)

and R.L.Kohnert,

Environ.

Sci &