Effect Of PASP On The Environmental Behavior Of Mercury And Its Mechanism In Fluvo-aquic Soil

Polyaspartic acid(PASP)is a potential water absorption resin,it is a promising material in the environmental protection and waste treatment because of its biodegradable and non-toxic characteristics.However,researches on the effect of PASP in the remediation of soil contaminated by heavy metals were still relatively less.In our research,through studying the effect of PASP on the bonding mechanism of Hg and its toxicity in solution,the effect of PASP on the speciation of Hg and its mechanism in fluvo-aquic soil,and pot experiment,we tried to illuminate the effect of PASP on the environmental behavior of Hg and its mechanism in fluvo-aquic soil.The main results and conclusions are:(1)Analysis of scanning electron microscope and fourier infrared spectrum showed that PASP was a porous network structure after freeze drying,and its-COO-would have reactions with Hg2+,Cd2+,Cu2+respectively.Hg2+ and Cu2+ could also react with the N of amide in PASP,however Cd2+ didn't.(2)Kinetics models showed that the adsorption of Hg in soil increased rapidly and the smoothly with the increasing time,PASP played a role in lowering the adsorption of Hg in soil.What's more,the pseudo second-order rate equation could,fit the two groups well.Five-step extraction procedure was conduct to extract the mercury speciations in soil.We found that PASP played a role in enhancing the proportion of active form of Hg in soil and the pseudo second-order rate equation was fit for describing the conversion process of five speciations of Hg.(3)Pot experiment showed that PASP had effects on the adsorption of Hg in plants,the distribution of Hg in the root,leaf and stem,the mercury speciations in plants and the subcellular distribution of Hg in plants.In particular,adsorption of Hg in plants was 12.26 mg·kg-1 in the group added with PASP Which increased 454.70%compared to control when the Hg concentration in soil was 120.00 mg·kg-1.What's more,Hg content was highest in plants,followed by leaf and stem.When added with PASP,Hg content in root and leaf were 8.65 mg·kg-1 and 2.96 mg·kg-1,respectively,Which increased 182.55%and 216.15%compared to control when the Hg concentration in soil was 120.00 mg·kg-1.