Biochar-plant Combined Remediation Of Soils Contaminated With PAHs And Heavy Metals

Biochar has been used for a long time as sorbents for organic and inorganic contaminants in soil and water.The article researched:(1)After adding biochar to soil,effects of the aging effect of biochar on the sorption of PAHs and heavy metals and the relationship between influence degree and soil organic matter content.(2)The effect of biochar-plants combined bioremediation of artificial addition of pyrene-Cu contaminated soil in laboratory and its relationship with soil organic matter content.(3)The effect of biochar-plants combined bioremediation of PAHs-heavy metal field-contaminated soil and its relationship with soil organic matter content.The main results are as follows:1、In the experiment of 180 days biochar aging,the adsorption capacity(Kd)to Cu and pyrene of soil of different organic matter contents(3.6%,1.7%and 0.8%)added with 2%and 5%biochar showed the trend of decreasing gradually with the extension of aging time and the adsorption capacity to Cu and pyrene of soil added with 5%biochar was higher than that of soil added with 2%biochar.After adding the same quality of biochar,the lower the content of organic matter of original soils,the weaker the adsorption capacity to Pyrene,but it showed the opposite to Cu.And with the increase of the pH of original soils,the adsorption capacity to Cu of the soil with biochar was enhanced.2、In artificially contaminated soil,addition with biochar had no effect on the biomass of potted plants of three tested soils(P>0.05),but it made the availability of pyrene of three tested soils and contents of pyrene of plants significantly reduced(P<0.05).The difference of organic matter content between the three tested soils(3.65%,1.34%and 1.20%)had a significant impact on the availability of pyrene and contents of pyrene of plants(P<0.05),specific performance:with the increase of the organic matter content of soil,the availability of pyrene was decreased,but contents of pyrene of plants were enhanced.After planting,the availability of pyrene was lower than that of original soil and the availability of pyrene of planted-soils was lower than that of unplanted soils(P<0.05).In the same treatment,the results of comparison of soil with different kinds of pollutants showed that the availability and contents of pyrene of soil adding with single pollutant were less than that of soil adding with compound pollutants(P<0.05).3、In natural field soil,addition with biochar had no effect on the contents of PAHs and heavy metals of three tested soils(P>0.05),but it made the biomass of potted plants increased(P<0.05).In the meantime,addition with biochar made the availability of PAHs of soils and contents of PAHs of plants significantly reduced(P<0.05),but it had no effect on that of heavy metals.Besides,the difference of organic matter content between the three tested soils(7.93%,5.08%and 2.04%)had no impact on the availability and contents of PAHs and heavy metals(P>0.05).After planting,planted-soils compared with unplanted-soils,the availability and contents of PAHs and heavy metals had no significant difference(P>0.05).