Soil and sediment, as important sinks for pollutants, are prone to the re-release of accumulated heavy metals and organic matter under changing environmental conditions, leading to secondary pollution and threatening ecosystems and human health. Traditional pollutant extraction technologies suffer from limitations such as long processing times and low efficiency. The development of rapid release extraction technology provides crucial support for pollution monitoring and remediation.
The release of pollutants in the matrix is regulated by multiple environmental factors. The release of heavy metals is closely related to pH value and redox conditions. Increased acidity enhances the competitive adsorption effect of ions, promoting the desorption of heavy metals. Under anaerobic conditions, the reduction of iron and manganese oxides leads to the release of bound heavy metals into water bodies. Organic matter, due to its hydrophobicity, is easily adsorbed by matrix particles, and its release efficiency is significantly affected by temperature and disturbance intensity. These characteristics provide a design basis for rapid extraction technologies.
Currently, rapid release extraction technologies have formed a multi-method system. A gaseous extraction device for organic matter, through optimized solvent and extraction conditions, can extract 16 controlled polycyclic aromatic hydrocarbons (PAHs) within 2 hours, with a low-ring PAH recovery rate of 80%-100%, and better repeatability than traditional methods. This technology is significantly superior to traditional methods such as Soxhlet extraction and microwave-assisted extraction in terms of reagent consumption and ease of operation.
Simultaneous extraction of heavy metals and organic matter has become a technological breakthrough. Cyclodextrin-based elution technology can simultaneously enhance the desorption efficiency of pollutants such as phenanthrene and cadmium, and effectively overcome the extraction difficulties caused by pollutant aging. Novel biodegradable chelating agents, through structural modification, can form stable complexes with heavy metals and enrich them in the organic phase, achieving extraction rates for multiple heavy metals such as cadmium and copper that are no lower than those of traditional reagents, realizing "one-step extraction and simultaneous purification."
With technological iteration, the rapid release extraction of pollutants from soil and sediments is developing towards higher efficiency, lower consumption, and multi-target capabilities. In the future, through material innovation and process optimization, the bottleneck of complex matrix interference will be further overcome, providing stronger technical support for environmental pollution control and ecological restoration.
