Study on the Remediation Effect of Biochar-chitosan Composite on Cd Contaminated Soil
[Objective]To explore the remediation effect of biochar-chitosan composite (CBC) on Cd contaminated soil.[Method]A pot exper-iment was conducted with ryegrass as the test plant,the changes of soil pH,total Cd content,available Cd content,biomass of ryegrass roots and leaves,and total Cd content in acidic low Cd soil,neutral high Cd soil and alkaline high Cd soil were investigated when CBC was added to 0, 0.5%,1.0% and 3.0%(W/W) respectively.[Result]The application of CBC could increase the pH of acidic and neutral soils.The available Cd decreased with the increase of CBC application,and reached a significant level when the application amount reached 3.0%.CBC could pas-sivate Cd activity in soil,and its passivation effect was closely related to the degree of soil pollution and acid-base property.With the increase of CBC application,the Cd content in the roots and shoots of ryegrass decreased,especially the effect on the aboveground part of plants was signifi-cant,directly indicating that CBC had a immobilization effect on Cd in soil.The BCF and TF of ryegrass decreased with the increase of CBC ap-plication rate,indicating that the application of CBC could reduce the migration of Cd from soil to the plant body,thereby achieving the effect of alleviating Cd toxicity.[Conclusion]The CBC can be used for the remediation of Cd contaminated soil,especially in heavily polluted acidic soils.
Biochar-chitosan composite (CBC)Soil acidity and alkalinityImmobilization remediationCd contaminated soilRyegrass