Dynamic surface tension measurements for the assessment of potable water quality

Talanta,Vol.23,pp.33g-341.Perg~n

Pressl,lg76.Printed

PRELIMINARY

DYNAMIC

SURFACE

TENSIGN

Institute

Loglio

of Physical

.#ATER

, U. Tesei,

Chemistry,

A.

FOR

Ficalbi

University

separation and identification 1 analysis. Normally, pollution

water

equivalent

concentration

considerably note

from

that different

of water this

fact,

which

considered. (that

is,

degree

capacity

In this activity, the

we have

two aims:

can be of practical

significance

is a difficult

is stated which

are

9,

activity

surface

free

in terms

may hand,

chemically

it is important

the surface

studies,

energy)

in

of the

differ

to

properties

In our

should

of substances

of water,

problem

encountered).

in environmental

opinion

be

present

in water

can be a significant

in addition

to the other

considered.

1) to propose use for

of the surface

Capponi

1976)

can affect

differences

of the quality usually

Gino

On the other

concentration,

the excess

quantities

materials

that the surface

in the assessment

paper

which

we feel

Via

surfactants

present.

neglected

OF

Cini

11 February

substance,

hundredfold

been

to change

and physical

reference actually

(even

Accented

individual

at the same

has heretofore

quantity

chemical

reveal

surfactants,

In particular, their

physical

substances

ASSESSMENT

Italy

due to such

of a standard

those

to a varying

of all

and R.

of Florence,

28 January_ 1976.

The

TKE

QUALITY

5012 1 Florence,

(Received

Britain

COMMUNICATION

MEASUREMENTS

?OTABLE

G.

in Great

a parameter

the routine

activity

correlated

examination

in studies

with

of potable

concerning

poltution

surface

water;

2) to

by

surfactants.

EXPERIMENTAL The

concentration

Longwell The

of anionic

and Maniece, dynamic

surface

apparatus

with

was

to avoid

taken

2

surfactants

of non-ionic tension

a recording mistakes

was

determined

surfactants

according

of potable

water

electrobalance,

samples

following

due to adsorption

339

according

was

measured

a procedure

on the wails

to the method

to the method

already

of the sample

of Greff

of et al.

3

by a Langmuir described. vessel.

Care

Preliminary

340

Comunioation

AND

RESULTS Parameter water,

related

to surface

defined

as

- lim

AY

/c ,

between

the ratio to pure

water

involved

accuracy).

Having

into consideration investigation

of the surface the surface

a concomitant of

ny

decrease

changes

as a function

concentration

and the surface

concentrations,

the value

proportionally value take

of

to

OY (~/XC.

cannot

be determined

predominant

contributors

negligible

sampling

MBAS

potable

water

river).

related

a ratio.

most

SA , whereas

of

the

at various roughly

concentration,

( SA

active

which

is

the value

, increases

activity

those

there

quantities,

activity.

surface

concentratic

a process,

at the same

to surface

low

other

z

the

rapidly,

substance

of the surface

The

and we take

for

at very

among

instant

substances function

one,

such

a given

is not

are

the

Thus,

we can

1, even if the

substances less

are

the

so give

the value continuous

flow

A comparison

the concentration

SA

cases

the overall

the substances

SA

present,

by standardization

parameter

with for

or,

treatment. halved,

line,

of

at least,

If the nature the same

( fed

of

from

a

allows

the

(all

samples

MBAS

taken

have

equal,

are

equal

measurement

of the surfactants

was

before

that the MBAS

values

would

or almost in some errors

taken

as

( after)

values

remained be expected

of each

cases

or very means

the nature

of them,

decrease

even

and after

of

varies

by about

the same, before

equal,

). This

is the same,

concentration

of the substances SA

samples

which

exceed

the percentage shows

which

values

quite

diagrams

plant also

of

AY i;?

of samples

activity

the value

of

ozone.

samples

concentration

pairs

the figure

concerns

values

treatment

of surface

therefore

can have

( the differences

shows

to eight

water

on the same

diagram

figure

relative

a municipal

surfactants;

of the water

of the two

was

from

( lower)

molar

The

, that is, the parameter

in both diagrams,

the

in other

of

water,

Substances)

segments

of non-ionic

treatment

values,

ozone

days

). The upper

can be seen

whereas

Active

the respective

V L c_

of

Blue

in potable

on different

to be free

attained

procedures.

of the value

found

following

for

is satisfactorily

of substances

taken

Placing

MBAS

AY 0)values

(Methylene

visualization

that,

of

activity

and of

different

different

such

in water

Following

, taken at a certain

to the value

and measuring

Surface

As

6

(static)

reproducibility

is decreased

contains,

Actually,

ny

of

contributions.

Reproducibility

were

function

increasing

from

ny .

of

than the static

present

respect quantity

in routine,analysis,

-of surfactants

as a parameter

*

rather

with

the concentration

to obtain

of practicability

This

for

. Moreover,

in which

is required

tension,

AY (y)

AT(~) is a monotonically

the ratio

latter

c

water,

the measurement

of substances

activity.

of

potable ppm),

of a solution

7

by

is the appropriate

surface

tension,

of time.

solutions

dilute

tension

procedure

of the surface

for

in

static

< 0.5

activity area

determined

dissolved

of the solution

for

surface

of a substance

tension

the importance

the dynamic

levels.

When

(c

experimental in mind

activity

of the surface

The

low

surface

can be approximately

However

very

( a rigorous

The

the difference

determination.

is normally

practical

dy/dc,

and the concentration.

in this

surfactants

activity, 5

DISCUSSION

50 %

though

FraliminaxyCommnication

341

3.30

own.

b*torb

a Ar(r) #

HBAS

0.30

tl ::

I

ozone

treatment

treatment, also

The

reducing

while

changes

to a large

above

the SA

8 On the contrary, the molar

degree

experimental

their

chemical

results

show

the nature

of the substances

that given

by the MBAS

concentration

physical

that the surface

quantity

conveniently materials

in terms

of modifying

drastically

present

Thus

present,

ozone

probab)y

with

information

information

On the basis

Moreover,

free

gives

Such

in water.

( or a parameter

surface

reduced,

parameter

of this

consideration,

by surfaetants

and the peculiar

energy

is additional

to

we

to it 1 is a significant

relation

pollution

of both the concentration

the excess

s s

nature.

that the SA

studies.

m

of the substances

parameter.

activity

in environmental

defined

are

concentration

concerning

can conclude

values

0

can be more

property

of these

of water.

REFERENCES 1.

G,

F.

Longman,

2.

J,

Longwelf

3.

R,

A.

Talanta,

and W.

Greff,

jun.,

D, E.

1975, Maniece,

A,

2,

621.

Analyst,

Setzkorn

1955, 80,

and W.

D.

Leslie,

167, 3. Am.

Oil

Chem.

SOC,~ 1965,

ff2*180, 4.

R.

Cini,

5.

R,

Defay,

A,

Ficalbi

and G.

I. Prigogine,

Adsorption

, pp. 94,

6.

H.

Lange,

J.

7.

G.

Loglio,

U.

Colloid Tesei,

A. 170. Sci,, A.

Loglio,

Mikrochim.

Bellemans Longmans 1965,

Ficalbi

and D. Green,

Acta, H.

1974,

Everett,

London,

203,

Surface

Tension

and

1966.

&Q, 50. and R,

Cini,

Inuuinamento,

1975 (No.

51,

23.