Biochar Of The Wheat Straw Amends Heavy Metals Pollution Of Pb?Cd In Soil

Recently,heavy metal has been paid widespread attention by researchers all over the world.Remediation technology of soils contaminated with heavy metal is to add biochar into soils and promote heavy metal in soils from available form to residual form through adsorption.In this paper,biochar preparation,its adsorption on heavy metals Pb?Cd and how does the form covers of heavy metals.The wheat straw to be the raw materials.Using Muffle furnace prepared biochars of 400?500?600?.The biochars were characterized by SEM-EDS.FITR.And research the effect of heavy metal about pyrolysis temperature,pH,adding.The effects of biochars on the transformation of heavy metals Pb and Cd were investigated by understanding the adsorption mechanism of biological carbon.Main results and summarized as follows:(1)The basic properties of biochar are closely related to the pyrolysis temperature of biochar.The pH of W400,W500,and W600 is:8.15,9.55,10.11;Three kinds biochars of productivity and ash is sorted from small to large:33.1%,25.6%,14.8%and 34.95%,30.81%,25.10%.With the increase of biochar pyrolysis temperature,carbon percentage from containing biochar were:W400<W500<W600;The percentage from biochar containing N,H and O were:W600<W500<W400.(2)In the adsorption experiment,the adsorption amount of Pb and Cd on biochar increased with the increase of pyrolysis temperature,adding and initial pH.The adsorption results of biochar for Pb conformed to the Freundlich model;the adsorption results of biochar for Cd conformed to the Langmuir model.(3)In potting experiment,the soil pH value increased with the number of days,the temperature of pyrolysis and the amount of adding.In potting experiment of Pb,the available of the single or compound pollution for heavy metal Pb decreased with the increase of days,the temperature of pyrolysis and the amount of adding.Compared with single pollution,the percentage of the available in the compound polluted was effectively reduced by adding biochar;the percentage of Pb reductive state in compound pollution is obviously lower than the percentage of single pollution;the percentage of oxidized is almost same to single pollution,but the residual form is obviously higher than the percentage of single pollution.(4)In the single or compound heavy metal pollution of Cd,the available of Cd decreases with the increase of days,the temperature of pyrolysis and adding.In the compound heavy metal pollution of Cd,the percentage of the available was significantly higher than that in single pollution.The percentage of oxidized and residual form is lower than that of single pollution.