Abstract:

Biodegradability is classified into primary biodegradability and ultimate biodegradability, which is an important factor to assess the impact of surfactants on the environment. With the development of society, people have paid more and more attention to the environment, and however, there are few systematic studies on the ultimate biodegradation performance of commonly used surfactants. Herein, a total organic carbon （TOC） analyzer combined with GB/T 21856—2008 “Chemical—Ready biodegradability—CO₂ evolution test” was used to analyze the ultimate biodegradability of 10 commonly used surfactants and liquid detergents of different brands and categories on the market, to examine their impact on the environment. This method simplified the experimental device and was easy to operate. In addition, it did not require to collect carbon dioxide, so the experimental data would not be able to deviate due to incomplete carbon dioxide capture. The error analysis of the experimental results shows that the method has stable experimental data and high repeatability. The results of ultimate biodegradability show that, the degradation rate of several common surfactants is above 60%, which meets the environmental requirements. Except for LAS, the rest are all more than 80%, indicative of excellent ultimate biodegradability. The degradation rate of some detergent products on the market is also greater than 80%, indicative of excellent ultimate biodegradability.

Key words: total organic carbon analyzer, ultimate biodegradation, surfactant, detergent