Effective remediation technologies for heavy metal polluted soils have not been developed until now. The currently used techniques, such as flushing or immobilizing washing, binding heavy metals to non-toxic forms, and others, have substantial limitations: they are very costly and are applicable to only limited soil types. The presented research was devoted to a use of brown coal to remediate soils polluted with heavy metals. Brown coal contains 46% (mass) of humic acids that can bind heavy metals into complexes. In addition, brown coal can bind heavy metals by physical absorption. Sorption-desorption behaviour of heavy metals onto brown coal was studied in several model experiments. The sample taken from the upper horizon of zonal soil was mixed first with different forms of metals. After a month of incubation in vessels, the sample was mixed with various amounts of brown coal. In another experiment, the samples taken from the upper layers of polluted urban soils were mixed with various amounts of brown coal. These soils were put into glass vessels for long-term incubation under optimum temperature and humidity conditions. The soil samples were taken out after a week, 1 month, or 6 months. The amounts of heavy metals in mobile forms dissolved in ammonium-acetate extract with pH 4.8 were measured using atomic absorption spectrometry and the polarographic method. The results were checked under field conditions, and the results showed that brown coal is an effective ameliorant of soils polluted by heavy metals.
展开▼
