Ether sulfates biodegradation

Schoberl et al. reported the data compiled in Germany for the most important industrial surfactants [383]. Natural and oxoalcohol sulfates have primary biodegradation results of 99% and 98-99%, respectively, by the confirmatory test. Natural and oxoalcohol ether sulfates biodegrade 98-99% and 96%, respectively, in the confirmatory test. Reported values of total biodegradation are shown in Table 35A and Table 35B. 

The biodegradation of surfactants is studied by means of many different tests and sometimes under different conditions. Some factors with significant influence on the results are uncontrollable factors and in other cases are not controllable. This causes a dispersion in biodegradability data that makes comparisons difficult. For this reason only general conclusions can be obtained from the data available. Swisher carried out an exhaustive collection of available data in his complete study on surfactant biodegradation [385]. Some basic and significant features of biodegradation of alcohol and alcohol ether sulfates are discussed below. 

Alcohol and alcohol ether sulfates are commonly considered as extremely rapid in primary biodegradation. The ester linkage in the molecule of these substances, prone to chemical hydrolysis in acid media, was considered the main reason for the rapid degradation. The hydrolysis of linear primary alcohol sulfates by bacterial enzymes is very easy and has been demonstrated in vitro. Since the direct consequence of this hydrolysis is the loss of surfactant properties, the primary biodegradation, determined by the methylene blue active substance analysis (MBAS), appears to be very rapid. However, the biodegradation of alcohol sulfates cannot be explained by this theory alone as it was proven by Hammerton in 1955 that other alcohol sulfates were highly resistant [386,387]. 

Alcohol ether sulfates also biodegrade rapidly but not as rapidly as alcohol sulfates. Primary biodegradation of alcohol (2 EO) ether sulfates determined in the same conditions as primary alcohol sulfates in Table 30 is shown in Table 33 as reported by Borsari [414]. 

Fisher [424] studied the biodegradation of C12 14 and its 2 EO, 3 EO, and 9 EO ether sulfates by inoculated organisms, obtaining the results shown in Table 34. 

TABLE 33 Primary Biodegradation of Alcohol (2EO) Ether Sulfates... 

TABLE 34 Primary Biodegradation of C1214 and C12 14 Ether Sulfates... 

However, they behave similarly to alcohol sulfates since linear alcohol ether sulfates are more easily biodegradable than branched alcohol ether sulfates. Also linear secondary alcohol ether sulfates are poorer than linear primary alcohol ether sulfates [425]. 

Alkylphenol ether sulfates are slightly more resistant to biodegradation than alkylbenzenesulfonates. Similarly to alcohol ether sulfates, this resistance increases with the degree of ethoxylation. Again there are some differences in favor of primary alkylphenol ether sulfates with respect to secondary alkylphenol ether sulfates [426]. 

Until the 1950s ether carboxylates were almost in very limited amounts in the textile industry. It was only in 1957 [9] that the first ethercarobxylates were mentioned, in combination with other surfactants such as alkyl sulfates and ether sulfates, for use in shampoos. In spite of the special properties of ether carboxylates, their use was low in the industry as well as in cosmetics at that time. This was also due to the fact that at that time properties such as toxicity, biodegradability, and mildness to the skin did not have the high priority they do now. 

Alkyl Ether Sulfates (AES) R=Cio C14 m=l-4 Liquid bath soaps, hair shampoos, and mechanical dishwashing agents. Ingredient in industrial cleaning agents - Effluents of seven representative STPs Cl2-15 AES 3 and 12 pg L 1 [15] Readily biodegradable in WWTPs under both aerobic and anaerobic conditions [18,29]... 

Alcohol ether sulfates. Ready aerobic biodegradation of AESs has been described [113], with co/(3-oxidation and cleavage of the sulfate and ether bonds attributed to the process [10]. However, molecular oxygen is not necessary for the two latter steps, and primary and ultimate degradation has been described under both aerobic and anaerobic conditions [114]. 

By far, the greatest apphcation of fatty alcohol is in the manufacture of fatty alcohol sulfate and fatty alcohol ether sulfate. These materials possess good foaming properties and ready biodegradability and are extensively used as base surfactants for laundry detergent products, shampoos, dishwashing liquids, and cleaners. 

Biodegradable ethoxylates derived from ALFOL Alcohol blends essentially 100% active used for sulfation to produce high quality ether sulfate surfactants and used directly as biodegable surfactants, emulsifiers, detergents, foaming agents and cleaners. 

Linear ethoxylates are used as the raw material for ether sulfates used in the production of biodegradable detergent formulations. 

Soil Metabolites of endosulfan identified in seven soils were endosulfan diol, endosulfanhydroxy ether, endosulfan lactone, and endosulfan sulfate (Dreher and Podratzki, 1988 Martens, 1977). Endosulfan sulfate was the major biodegradation product in soils under aerobic, anaerobic, and flooded conditions. In flooded soils, endolactone was detected only once, whereas endodiol and endohydroxy ether were identified in all soils under these conditions. Under anaerobic conditions, endodiol formed in low amounts in two soils (Martens, 1977). These compounds, including endosulfan ether, were also reported as metabolites identified in aquatic systems (Day, 1991). Endosulfan sulfate was the major biodegradation product in soils under aerobic, anaerobic, and flooded conditions (Martens, 1977). In flooded soils, endolactone was detected only once whereas endodiol and endohydroxy ether were identified in all soils under these conditions. Under anaerobic conditions, endodiol formed in low amounts in two soils (Martens, 1977). 

Functions as a co-emulsifier for silicone in cleaner polishes and mold release agents, and as an all purpose oil and fat emulsifier in industrial lubricants. For textile applications, this biodegradable, oil-soluble, water-dispersible ether is used as an emulsifier for mineral oil in lubricants such as coning oils. When sulfated, it forms a high-foaming anionic surfactant. 

Following previous studies on lauryl sulfate and AES, Cuzzola et al. [44] also studied the Fenton oxidation products of AEO and NPEO. The aerobic biodegradation of AEO and NPEO and anaerobic biodegradation of NPEO were studied by Schroder [27] by means of FIA-MS and LC-MS and MS-MS in positive-ion and/or negative-ion APCI. Methyl ethers of AEO ate persistent in aerobic conditions. NPEO degradation results in NPEC. Anaerobic biodegradation of NPEO results in nonylphenols. 

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