The Effects Of Various Enhancers On Ramie Absorption Of Cadmium In Contaminated Soil

Phytoremediation is the treatment of large-scale mild cadmium contaminated soil,more effective and economical means of repair.Ramie has a strong ability to enrich the cadmium,and has excellent drought and waterlogging characteristics,geographical and weather effects of its growth factor is very small,so it is often considered to be an excellent super tired plant to repair cadmium and cadmium and other heavy metals complex contaminated soil.However,during the process of phytoremediation,ramie has shown the shortcomings of biomass and cadmium in the underground part more than ground part,which is often used with different enhancers.The effects and mechanisms of different enhancers are different.In this paper,we will analyze the enhancers(the synthetic chelating agent,small molecule organic acids,rhizosphere probiotics)by leaching experiments and pot experiments to discuss how to further improve the efficiency of ramie on heavy metals in soil.The results showed that the synthetic chelating agent had a significant effect on the outflow of cadmium in the original soil,the faster the outflow rate of cadmium.The maximum amount of leaching solution is 8 ?mol/kg,and the distribution of cadmium content decreased significantly.After the leaching of small molecule organic acids,active heavy metal content decreased significantly,the maximum amount of leaching solution is 4~6 ?mol/kg but there are still some residues,the middle of a small amount of heavy metals decreased.The effect of cadmium was not significant after the rhizosphere probiotic and the maximum amount of leaching solution is only 1 ?mol/kg.The results showed that the total cadmium reduction in the so il the amount of cadmium in the soil and the cadmium concentration accumulation in the soil were consistent,and the total cadmium content in the soil.Reduced from high to low: EGTA> EDTA> Citric acid> Bacillus subtilis> Pseudomonas fluorescens> Tartaric acid> Control.The highest group was 80% more efficient than the control group.In addition to repair effects,the potential risks of various types of enhancers,repair capacity,sources obtaining,price and other aspects are also important factor to be considered.Which is the most economical to use EDTA as a reinforcing agent,about half of citric acid and bacteria.All the enhancers could increase the enrichment coefficient of ramie.The purification rate of ramie soil in the group of synthetic chelating agent can reach 1.2%,and the purification rate of the small molecular organic acid group of ramie soil can reach 1%,that is more than 0.46% of the control group.From the aspects of soil purification rate and bioconcentration factors,the synthetic chelating agent had the best effect with citric acid,and the synthetic chelating agent in this experiment showed low toxicity and the other biotoxic conditions of the enhancer are negligible.