Many chemically synthesized surfactants damage the ecological environment due to their poor biodegradability, toxicity, and tendency to accumulate in ecosystems. In contrast, biological surfactants—characterized by easy biodegradability and non-toxicity to ecological systems—are better suited for pollution control in environmental engineering. For example, they can serve as flotation collectors in wastewater treatment processes, adsorbing onto charged colloidal particles to remove toxic metal ions, or be applied to remediate sites contaminated by organic compounds and heavy metals.
1. Applications in Wastewater Treatment Processes
When treating wastewater biologically, heavy metal ions often inhibit or poison microbial communities in activated sludge. Therefore, pretreatment is essential when using biological methods to treat wastewater containing heavy metal ions. Currently, the hydroxide precipitation method is commonly used to remove heavy metal ions from wastewater, but its precipitation efficiency is limited by the solubility of hydroxides, resulting in suboptimal practical effects. Flotation methods, on the other hand, are often restricted due to the use of flotation collectors (e.g., the chemically synthesized surfactant sodium dodecyl sulfate) that are difficult to degrade in subsequent treatment stages, leading to secondary pollution. Consequently, there is a need to develop alternatives that are both easily biodegradable and environmentally non-toxic—and biological surfactants precisely possess these advantages.
2. Applications in Bioremediation
In the process of using microorganisms to catalyze the degradation of organic pollutants and thereby remediate contaminated environments, biological surfactants offer significant potential for on-site bioremediation of organically polluted sites. This is because they can be directly utilized from fermentation broths, eliminating the costs associated with surfactant separation, extraction, and product purification.
2.1 Enhancing the Degradation of Alkanes
Alkanes are the primary components of petroleum. During petroleum exploration, extraction, transportation, processing, and storage, inevitable petroleum discharges contaminate soil and groundwater. To accelerate alkane degradation, adding biological surfactants can enhance the hydrophilicity and biodegradability of hydrophobic compounds, increase microbial populations, and thereby improve the degradation rate of alkanes.
2.2 Enhancing the Degradation of Polycyclic Aromatic Hydrocarbons (PAHs)
PAHs have garnered increasing attention due to their “three carcinogenic effects” (carcinogenic, teratogenic, and mutagenic). Many countries have classified them as priority pollutants. Studies have shown that microbial degradation is the primary pathway for removing PAHs from the environment, and their degradability decreases as the number of benzene rings increases: PAHs with three or fewer rings are easily degraded, while those with four or more rings are more challenging to break down.
2.3 Removing Toxic Heavy Metals
The contamination process of toxic heavy metals in soil is characterized by concealment, stability, and irreversibility, making the remediation of heavy metal-polluted soil a longstanding research focus in academia. Current methods for removing heavy metals from soil include vitrification, immobilization/stabilization, and thermal treatment. While vitrification is technically feasible, it involves substantial engineering work and high costs. Immobilization processes are reversible, necessitating continuous monitoring of treatment efficacy post-application. Thermal treatment is only suitable for volatile heavy metals (e.g., mercury). As a result, low-cost biological treatment methods have seen rapid development. In recent years, researchers have begun utilizing ecologically non-toxic biological surfactants to remediate heavy metal-contaminated soil.
Post time: Sep-08-2025