New Type Cd With The Physic-chemical Property And Remediation Of Contaminated Soil By Cadmium

The pollution of soil heavy metal has become a major factor restricting the effective utilization of land resources in most areas. The heavy metals reduced to noting in technology and economy are not feasible, but if the goal is reducing heavy metal enter the food chain,the goal becomes more simple and economical. It is said that in the past 50 years of global emissions to the environment of the Cd content reached 2.20 x 104 t, Cu 9.39 x 105 t, Zn 1.35 x 106t, Pb 7.83 x 107t. Human use of cadmium has a long history, which makes the material containing cadmium accumulation in the environment, the environment contains substances containing a large amount of cadmium. In the serious of global environment taday, we response to cadmium pollution give enough attention and take the necessary measures to minimize the harm.The purpose of this research:by chemical synthesis of stable chemical leaching agent, selected a suitable clean soil(Cd<<0.2mg/kg), then the added cadmium compounds after two months of aging and analysis of chemical leaching agent which is absorbed cadmium control effect, and migration of Cd in soil from running, morphology and off washing effect changes to explore the control mechinsm.Main research contents are as follows:(1) the "Hyperion and liquid phase synthesis method for preparation of water soluble complexes of cadmium and its a series of characterization. (2) the effects of n (Cd/HSCH2COONa), pH of the solution, reaction temperature, reaction concentration (c) complexes were investigated on the synthesis of cadmium, and determine the synthesis process conditions. (3) compared to Cadmium Complexes of determining the scope of the stability constant. (4) of soil polluted by heavy metal cadmium on remediation of cadmium contaminated, the effects of solution pH, reaction temperature (DEGC), concentration (mmol/L), liquid solid than the impact factors of cadmium in soil remediation and to determine the optimal process conditions.Research results are as follows:(1)by IR, elemental analysis, and UV analysis method to the synthesis of novel cadmium complexes were characterized and get the laboratory synthesis of novel water soluble cadmium coordination compounds and molecular type 2 for Cd (NaSCH2COONa)2. The complex has good water solubility and thermogravimetric analysis of thermal decomposition temperature is about 190 ℃.(2) by comparing the research can be seen that Cd (NaSCH2COONa)2 with the stability constants between the EDTA-Cd complex stability constant (1016) and Cd(C7H5O6S)2 stability constants (1029.06). (3) the optimum conditions of the synthesis of Cd (NaSCH2COONa)2:pH=11, concentration of 0.5mol/L, molar ratio of n=4, temperature of T=40 (℃). (4) the complexes should be light, temperature is not higher than 45℃,7= pH= 10 under the condition of preservation is the most appropriate. (5) determine on heavy metal pollution of cadmium in soil remediation of optimum process conditions: pH, concentration is 0.1 mol/L, the molar ratio of solid to liquid ratio is 30:1, temperature T=35 (℃).