Chemistry Reference
In-Depth Information
AS
6%
AES
10%
Soaps
37%
APE
10%
AE
12%
LABS
25%
Figure 1.2.
Surfactant consumption by type in the major industrialized areas for 2000.
The linear alkylbenzene sulfonates (LABS) family is probably the world's most
important surfactant family, taking into consideration their wide applicability, cost-
effectiveness, and overall consumption levels. If raw-materials prices and availabil-
ity (i.e., normal paraffins and benzene) remain stable, there is little reason to expect
the situation to change in the near future. If feedstock prices increase significantly,
however, alcohol sulfates and related materials derived from fat and vegetable
sources may become attractive alternatives.
There do exist some concerns and questions about the overall long-term ecolo-
gical impact of LABS. Of particular importance are the following:
1. LABS are not easily biodegradable under anaerobic conditions.
2. Limited data are available on what happens when dissolved LABS enters a
waterway and what its effects on adsorption and sedimentation will be.
3. When treated sewage sludge is transferred to the soil, what effects do residual
LABS have on adsorption and soil wetting, and what is their final fate?
4. What is the true, ultimate biodegradability of LABS in terms of residues,
metabolites, and other materials?
In terms of raw-materials availability, soaps are very desirable products. As already
noted, soap is especially important in less industrialized countries because the
sources are readily renewable, relatively speaking, and usually locally grown. In
addition, the necessary production facilities and technology are relatively simple
and inexpensive. In many modern applications, however, soaps are neither efficient
nor effective, and cannot really replace the synthetic surfactants. While the use of
''natural'' soaps seems to have a high emotional rating among environmental
groups due to their long tradition of use and ''organic'' sources, their inferior per-
formance characteristics in many common situations require the use of much larger
quantities of synergistic additives (e.g., phosphates and other ''builders'') to achieve
