Research On The Preparation And Characterization Of Vinasse-based Biochar And Remediation Of Heavy Mental Pollution In Soil

The rapid development of the economy,the accelerating pace of urbanization,and the increasing frequency of industrial and agricultural activities have all caused serious heavy metal pollution to the soil.In order to solve this problem,many governance technologies came into being.Compared with other remediation methods,soil solidification technology has been widely used due to its relatively cost-effective,simple and fast advantages.Biochar has attracted more and more attention as a curing agent.This subject is based on the utilization of brewery waste lees,using its pyrolysis biochar to conduct experimental research,examining the effect of pyrolysis final temperature on biochar properties,biochar impact on soil physical and chemical properties,and the fixation effect of soil heavy metal pollution.The following conclusions are obtained:Vinasse from brewing waste is suitable as raw materials for pyrolysis of biochar.The yield of biochar will gradually decrease as the final pyrolysis temperature increases.The properties of biochar will change due to the difference in final pyrolysis temperature.The p H value and ash content of VB400,VB600 and VB800 all increase with the increase of the final pyrolysis temperature;with the continuous decomposition of organic matter and the occurrence of dehydration reaction,the H/C ratio and O/C ratio of biochar all decrease with the increase of the final pyrolysis temperature;correspondingly,the surface functional groups continue to decrease and the cation exchange capacity(CEC)decreases.The high temperature also gave birth to the pore structure of biochar.The scanning electron microscope image of VB800 showed a loose and porous structure.BJH pore size analysis also showed that it had the most micropores and mesopores,and the specific surface area was much larger than VB400 and VB600.The addition of biochar will have an important impact on the physical and chemical properties of the soil.In this paper,four representative indexes are selected: soil p H,conductivity,organic matter content and cation exchange capacity(CEC)for analysis: VB400,VB600 and VB800 will be mixed with soil of 2% and 4% ratios produce different experimental results.VB800 can increase soil p H and conductivity more than VB400 and VB600;VB400 can increase soil CEC more than VB600 and VB800;the three have little effect on soil organic matter.But with the increase of the addition ratio(from 2% to 4%),these effects will be strengthened.This effect is beneficial to the fixation of heavy metals in contaminated soil,and is usually used as an "indirect mechanism" for biochar to repair heavy metal pollution in soil.The addition of biochar can effectively reduce the content of heavy metals in the soil.The fixing effect of heavy metals is related to the type and addition ratio of biochar.For Cd,the immobilization effect is VB400>VB600>VB800;for Pb,the immobilization effect is VB400>VB800>(?)VB600,indicating that the immobilization effect of both is dominated by the specific adsorption of organic functional groups;for Cu,the immobilization effect is VB800>VB600>VB400,because although VB800 has fewer surface functional groups,its ash content is high and can significantly change the state of the soil.The maximum immobilization rates of biochar to Cd,Pb,and Cu in contaminated soil are quite different,being 46.3%,26.9%,and 69.6%,respectively.And SPSS25.0 software was used to conduct a two-factor analysis of variance for "biochar types" and "addition ratio",and it was determined that the dominant factors for the immobilization effect of the three heavy metals were all "biochar types".Finally,the potential ecological hazard index method also shows that biochar has positive significance for the remediation of soil heavy metal pollution.