The Pollution And Passivation Remediation Of Soil As,Sb In Typical Antimony Mining Areas

Dongfeng Antimony Mine is one of the famous large antimony mines in in Dushan County,Guizhou Province.In recent years,due to the large-scale exploitation of antimony resources,the content of Sb in the soil,water and air of the mining area has risen sharply.Which poses a serious threat to the health of human beings and the whole ecosystem.Therefore,it is of great significance to study the characteristics of Sb and As pollution existing in the soil of antimony mining areas and the remediation of Sb pollution soil.This article will study the following three aspects:(1)In order to understand the Sb and As pollution in the soil and plants of the antimony mining area,the soil and plants surrounding the old smelting plant in Dongfeng antimony mining area were taken as the research objects.Twelve soil samples and six corresponding plants were collected from three sites,the total amount,forms,physical and chemical properties,Sb and As content in all parts of the plant were measured,and the single factor pollution index and nemero comprehensive pollution index were used for evaluating the pollution of Sb and As in soil.Correlation heat map and redundancy(RDA)analysis,spearson correlation analysis of the correlation and impact of soil physical and chemical properties on the total amount of Sb and As,and correlation ofsoil Sb and As on the amount of Sb,As of plant parts.The translocation factor and bioconcentration factor were used to screen the remediation plants existing in the mining area.The results showed that the soil Sb pollution is serious in the three samples of the mining area,and the As pollution is light.The form of Sb,As in the soil is mainly residues,accounting for more than 90%.There was a positive correlation between conductivity and As,pH and total Sb,and a negative correlation between TN and Sb.TC was negatively correlated with Sb and positively correlated with TN and CN.OM was negatively correlated with Sb,As was positively correlated with Ab,but it did not reach a significant level.The enrichment of Sb and As in various plants changes with the change of plant species,and As and Sb in various parts of the plant increase with the increase of the content in the soil.There was a significant positive correlation between the As content in the root and the As content in the stem,but the correlations between the other parts were not obvious.The residue states of As and As were significantly positively related to leaf-Sb and stem-Sb and root-As,the oxidizable states of Sb and Sb were extremely significantly positively related to root-Sb,leaf-As,and stem-As.Asplenium and typha could be use as candidate plants for combined pollution of Sb and As.(2)In order to study the desorption and adsorption behavior of Sb in the passivator,three passivation agents including lime,modified zeoliteand calcium magnesium phosphate were selected for experiments.The results showed that with the increase of Sb in the solution,the desorption and adsorption of Sb by the three passivators increased gradually.Under the same concentration treatment,the desorption and adsorption were lime>modified zeolite>calcium magnesium phosphate.The desorption at Sb concentrations of 1,10,and 100 mg / L was divided into two stages,and the desorption amounts reached equilibrium at 6 hours.All three passivation agents met polynomial equations,power functions,exponents,and logarithmic models.Among them,the polynomial equations fit the adsorption kinetics best.(3)In order to investigate the effect of passivation agents on Sb contaminated soil,three passivation agents including lime,calcium magnesium phosphate fertilizer,modified zeolite,and mixed passivation agents were used to passivate the contaminated soil with Sb concentrations of 10,30,and 50 mg / kg.cynodon dactylon was used as the experimental plant to carry out the pot experiment,using BCR continuous extraction method to determine the form of Sb in the soil under the treatment of each passivator,and to determine the physical and chemical properties of the soil and the basic physiological indicators of the plant.Based on this study for studyig the effect of the soil polluted by Sb after adding the passivator.The results showed that pH,conductivity and organic matter in the soil compared with the control increased withthe improvement time,and pH,conductivity and organic matter in one month,four months and six months showed that the treatment with three passivators(lime+calcium magnesium phosphate+modified zeolite)was better than other treatments.The addition of passivator has an effect on Sb in polluted soil,and then affects the effectiveness of plants.When Sb pollution of mixed soil was 10 mg/kg,the content of residue decreased,and the content of other forms increased.When Sb pollution of mixed soil is 30 mg/kg,the content of various forms does not change much.When Sb pollution of mixed soil was 50 mg/kg,the content of each form increased one month and six months after the application of single and mixed passivator.The addition of inactivating agent can increase the plant height,dry weight and root tiller number of Cynodon dactylon in the polluted soil.And reduce Sb content in the cynodon dactylon.