2. Introduction
• Domestic waste water is one of the important
pollution sources affecting the water quality
adversely in many countries.
• Waste waters containing detergents are the
basic constituents of organic pollutants and they
cause great environmental damages by
introducing into the soil, lakes and rivers.
3. • Detergents are the mixtures of surfactants and
their isomers and preferred to soap because of
their many superior properties. As a result of
economic development and population growth,
environmental problems caused by detergents
are increasing day by day.
4. Chemistry …..
• Alkyl benzene sulfonates are the major
components of anionic detergents.
• alkyl benzene is a family of organic compounds
with the formula C6H5CnH2n+1.
• Typically, n lies between 10 and 16, although
generally supplied as a tighter cut, such as C12C15, C12-C13 and C10-C13, for detergent use .
• This molecule has a polar( sulfonate ) and non
polar(alkyl) end.
5. • Alkyl benzene sulfonates classified into 2
groups:
branched and linear chain
6. • Type of substance : organic acid sodium
salt
• Physical state(20ºC): solid
• Molecular weight: 342.4
• Vapour pressure(25ºC) : 3x10-13 Pa
• Boiling point : 637ºc
• Melting point: 198.5ºc
• Water solubility: 250g/l
• Density : 1.06kg/l
• pH (5%LAS soltn): 7-9
• Trade name: Marlon A
7. ABS & LAS
• Linear and branched alkylbenzene sulfonates
(LAS and ABS) are the most important
anionic surfactants widely used in the
formulation of house hold detergent and
industrial cleaning products.
• The concentration of this anionic material in
the detergent industries wastewater is too
high and discharges generate critical
problems and unrestorable damages such as
poisoning of waterlife , pollution of ground
water, and formation of foams in rivers.
8. • Although ABS was an effective detergent it
has slow rate of biodegradation in the
environment.
• It become apparent that ABS based
detergent were contributing to pollution of
lakes and streams by forming relatively stable
foams .
• Resistance of branched ABS to biochemical
degradation in aquatic environments also
posed to threat to municipal drinking water
supplies , which were using surface water as
9.
10. • LAS was first commercialized in 1965s as a
replacement for the poorly biodegradable
Alkylbenzene Sulfonate (ABS) which caused
persistent foam in sewage treatment plants,
streams and rivers. LAS was the first surfactant
introduced to solve an environmental problem.
• LAS has been shown to affect the flora and
fauna of aquatic ecosystems. It has been
observed that this compound denatures proteins
in the cell membrane, altering the permeability of
the membrane to nutrients and other chemical
substances , but it can readily destroyed by
11. Manufacturing route
• The first ABS was obtained by the FriedleCrafts alkylation of benzene with polyproplene
tetramer. The tetramer is a mixture of C12
olefins. As a result the corresponding ABS is
highly branched .
• The detergent produced is then sulfonated
with oleum or sulfer trioxide followed by
neutrilization with NaOH or soda ash.
• LAS is comprised of linear alkyl carbon chains
(C10-C13), SO3- and Na+. LAS is made from
kerosene and benzene through Linear
12.
13. Human health assessment
• The toxicological data show that LAS was
not genotoxic in vitro or in vivo.
• The critical adverse effect identified after
repeated long term high dosing of LAS to
animals was a change in renal
biochemical parameters.
14. Environmental risk assessment
Aquatic
• Toxicity tests have been conducted with LAS on a wide
range of fresh and saltwater fish, invertebrates and
algae.
• Acute toxicity of LAS to most fish and invertebrates is in
the 0.5 mg/L to 20 mg/L range.
• The aquatic toxicity of LAS to algae has a greater spread
of responses, with 90% of the species having an EC50
between 0.1 mg/L and 100 mg/l .
•
The alkyl chain length affects the acute toxicity of LAS.
The EC50 for the different chain lengths of LAS to
Daplznia magna were found to be 0.68, 2.6, 5.9, 21.2
15. Sediment
• The results from the U.S.G.S. study
indicate that LAS concentrations in the
sediment are more than five times lower
than the lowest NOEC reported for the
most sensitive species tested.
• The data indicate that LAS is not
impacting sediment organisms in spite of
the large wastewater input and the lack of
secondary treatment by several large
metropolitan cities along the river.
17. • Mechanism of breakdown involves the
degradation of the straight alkyl chain, the
sulphonate group and finally benzene ring.
• Alkyl chain breakdown starts with the
oxidation of the terminal methyl group( oxidation) through alcohol, aldehyde to
carboxilic acid.
• The reaction is catalyzed by alkane
monooxygenase and two dehydrogenase.
18.
19.
20. • The carboxylic acid undergoes -oxidation
and two carbon fragment enters TCA cycle
as acetyl CoA.
• In case of ABS , the side chain methyl
group cannot undergo -oxidation by
micro organisms
• Second stage of breakdown , is the
degradation of sulphonate group.
Desulphonation occurs through either of
the 3 proposed way:
21.
22. • Breakdown product of LAS is sulphite ,
and is oxidised to sulphate in the
environment.
• Loss of alkyl and sulphonate group from
LAS leaves either phenylacetic or benzoic
acid
• Microbial oxidation of phenylacetic acid is
fumaric and acetoacetic acids and
benzene is converted to catechol
23. • The complete biodegradation of
surfactants requires a consortium of
bacteria due to the limited metabolic
capacities of individual microorganisms.
• Consortium of bacteria comprises of
Pseudomonas aeroginosa, Bacillus
subtilis, Bacillus aglomerans, Bacillus
cereus, Bacillus alvae
24. • Cultures isolated from the fresh water
layer of river had greater ability to degrade
LAS than those from the underlying saline
water layer.
• Degradation rates was faster for the
longest alkyl chain LAS and slower for
isomer having the sulphophenyl group
situated in the middle of the alkyl chain.
25. Literature cited
•
•
Biodegradation of Surfactants in
the Environment. Matthew J
Scott , Malcom N Jones
FATE OF THE BENZENE RING OF •
LINEAR ALKYLBENZENE
SULFONATE IN NATURAL
WATERS . R. J. Larson* and A. G.
Payne ., APPLIED AND
ENVIRONMENTAL
MICROBIOLOGY.
•
•
BIODEGRADATION OF LINEAR
ALKYL BENZENE SULFONATE
BY BACTERIAL CONSORTIUM.
Praswasti PDK Wulan, Misri
•
Gozan, Anondho W, Dianursanti,
Mahmud S
. A. J. Willetts and R. B. Cain.,
Biochem. J. (1972)
LINEAR ALKYLBENZENE
SULFONATE TOLERANCE IN
BACTERIA ISOLATED FROM
SEDIMENT OF TROPICAL WATER
BODIES POLLUTED WITH
DETERGENTS. Kehinde I.T.
Eniola & Albert B. Olayemi
LAS -Linear Alkylbenzene
Sulphonate , Revised
ENVIRONMENTAL Aspect of the
HERA Report February 2013
Linear Alkylbenzene Sulphonate The Soap and Detergent
Association
