Adsorption Characteristics Of Biochar To Mercury And Its Effect On Bioavailability Of Mercury

Zhanggutai sandy soil is taken as the object of this research,Adding biochar with different concentration gradients to mercury-contaminated soils,through relevant experiments,The effect of biochar on the physical and chemical properties of sandy soil was studied.The adsorption characteristics and mechanism of biochar on mercury were further studied.Adsorption mechanism of heavy metals coexisting in solution by biochar was discussed..Finally,the effects of biochar on plant availability of mercury were investigated.The results provide a scientific basis for the control of heavy metal pollution in regional soil.The main results are as follows:?1?biochar has a certain adsorption capacity for heavy metals,the maximum removal rate of biochar on mercury reached about 97%.With the increase of biochar dosage,the particle size of biochar decreases,the pH value of solution increases,and the reaction temperature increases,so does the total amount of Hg²⁺adsorbed by biochar in solution.?2?The adsorption of heavy metals by biochar satisfies the quasi-second-order kinetic equation,which indicates that it is a multi-step reaction,including physical diffusion process and chemical adsorption process.Under the condition of metal coexistence,competitive adsorption reaction will occur between Cu²⁺and Hg²⁺.?3?With the increase of biochar application,the content of malondialdehyde in oat grass increased first and then decreased.The application of biochar to mercury-polluted sandy soil reduced the activities of Peroxidase,superoxide dismutase and catalase in oat grass to a certain extent,and also effectively adsorbed and fixed Hg in sandy soil.At the same time,the mercury content in roots and aboveground parts of oat grass decreased significantly?0.01<P<0.05?,indicating that biochar could reduce the bioavailability of mercury and the absorption of mercury by oat grass.