The Effect Of Peptide On The Forms Of Cd In Soil Polluted By Cadmium

With the rapid development of industry and extensive use of chemical fertilizers,heavy metal pollution about soil is becoming more and more serious.At present,the passivation remediation in all methods is the most effective emergency measure in remediation of heavy metal pollution soil.This research involves applications of protein peptide which has independent intellectual property rights in heavy metal pollutionsoilremediation.Including sediment of protein peptide to cadmium in solution.determination of effective cadmium content in the soil.analysis of cadmiumform change in the soil and plant' s absorption of cadmium,all researches were carried out to establish research foundation about application of protein peptide in passivation remediation of heavy metal pollution soil1.sediment effect of protein peptide on cadmium ion in solutionCadmium ion in solution can be combined with the carboxyl group and the thiol groupcontained in protein peptide by precipitation which can reduce the concentration of soluble cadmium ion in solution.Protein peptide has the passivation potential of heavy metal ions according to above feature.In order to test whether the protein peptide has the capability of passivation to Cd in soil,experimental programs about the effect of different protein peptideconcentration on the precipitation of cadmium ions in solution at different pH were designed.The results showed that 1%,1.5%protein peptide respectively reducecadmium ion concentration by 11%and 14%at pH 8.5;and 1%,1.5%protein peptide respectively can reducedcadmium ion concentration in solutionby 7.7%and 26.3%at pH 6.0.2.the effect on available cadmium in contaminated soil of protein peptide and its compoundThe sediment experiment had tested that protein peptide could reduce concentration of cadmium on in solution via the integration of carboxyl and sulfydryl.To reduce concentration of cadmium in the polluted soil,it was practicable to integrate protein peptides of various concentrations,with K2CO3,glucose and mixture of K2CO3 and glucose separately to further passivate the precipitation of soil cadmium ion.According to National Standard Method(GB/T23739-2009),the experiment result is as follows.We combined 1%peptide and 1.5%peptide with K2CO3,glucose and mixture of K2CO3 and glucose separately.On the 15th day of cadmium polluted soil passivation,all the treatment reduced available cadmium in the soil by 2.8%to 31.2%.the most effective treatment was the combination of 1.5%peptide and 1%K2CO3,reducing available cadmium by 31.2%.On the 45th day,the most effective treatment was still the combination of 1.5%peptide and 1%K2CO3,reducing available cadmium by 30%.The worst treatment was the combination of 1%peptide and 1%glucose,increasing available cadmium by 1.7%.The reason was that glucose,utilized by edaphon,created organic acid which increased the available cadmium.3.the effect of peptide and peptide compound on forms of Cd on contaminated soilPeptide and its compound could change the form of Cd in polluted soil,and then change the available Cd.The experiment result of the acid soluble Cd(exchangeable form,carbonate cadmium and carboxyl combined cadmium)is as follows.1%peptide and 1,5%peptide were respectivelycombined with 1%K2CO3,1%glucose and mixture of K2CO3 and glucose.On the 15th day,all the combination's acid soluble Cd changed from-3.3%(lowest)to 9.7%(highest).The combination of 1%glucose and 1%K2CO3 increased maximally(9.7%).On the 45th day,all the combination's acid soluble Cd changed from-1.9%to 25%.The acid soluble Cd about combination of 1%glucose and 1%of K2CO3 increased maximally 25%,and acid soluble Cd in combination of 1.5%protein peptide and 1%glucose reduced by 1,9%(compared with blank control).As For reducible cadmium,on the 15th day,the range of reducible cadmium was reduced by 0.5%?16.2%.The combination of 1.5%protein peptide and mixture of 1%1%and 1%glucose reduced reducible cadmium maximally(16.2%),and the combination of 1.5%peptide only reduced reducible cadmium by 0,5%.On the 45th day,all the treatment containing 1%K2CO3 couldreduced by 8.8%?13.6%.As for oxidizable cadmium,on 15th day,the oxidizalbe cadmium in all treatment is reduced by 8.8%?32.5%.1.5%peptide and 1%K2CO3 reduced oxidizable cadmium by 32.5%in maximum.On the 45th day,the oxidizable cadmium in all treatment was reduced by 19.6%?44.7%and the combination of 1.5%peptide and 1%K2CO3 reduced oxidizable cadmium maximally(44.7%).As for residual Cd,on 15th day,treatment of 1.5%peptide and the combination of 1.5%peptide and mixture of 1%K2CO3 reduced residual cadmium by 18%and 23.8%.On 45th day,these treatment were unable to change the residual cadmium in the soil.4.the effect of protein peptide and its compoundon on plant absorbing cadmiumBased on the research about effect of peptide and its compoundon available Cd in polluted soil,the effect of peptide and its compound on plant absorbing cadmium had been researched when matA.tuberosum Rott ex Spr and Spinacia oleracea Linnby were used as experimental materials by pot experiment.The results showed the combination of 1.5%protein peptide and 1%K2CO3 could maximally reduce the plant content of Cd in the polluted soil.while the first harvest of leeks,the Cd content was reducedby 48.7%(compared with control).the second harvest of leeks,Cd content was reduced by 24.5%.As for spinach,Cd content was reduced by 18.9%.The reason thatCd absorptive amount in plantswas decreased was Lead byprecipitation of carboxyl and sulfydryl in peptide,and competitive inhibition of calcium.All of the above research results will provide a research foundation which the qualified crops are cultivated in polluted soil.