Study On The Influence Of Wood Vinegar On The Repair Of Heavy Metals Contaminated Soil

Wood vinegar(WV)is a reddish brown liquid,which is a by-product of high-temperature pyrolysis of woody biomass to produce carbon.It has been widely used in many fields thank to its strong antioxidation,anti-inflammatory and bacteriostatic properties.In the agricultural field,wood vinegar has already been used as soil amendment,plant growth accelerator and insecticide,but there are few reports on the effect of wood vinegar on repair heavy metals contaminated soil or related aspects.Due to the large amount of organic acids,phenols and other substances in wood vinegar,the adsorption effect and adsorption performance of soil heavy metal adsorbents may be affected.Thus,this thesis focuses on the study of the influence of wood vinegar on repairing heavy metal contaminated soil,mainly including the following two aspects.Firstly,the effect of wood vinegar on the adsorption effect of adsorbents with heavy metals was investigated.Four common soil heavy metal adsorbents,including phosphate rock powder,fly ash,zeolite and bentonite,were selected experimentally.Three heavy metal ions consistin of Pb(II),Cd(II)and As(III)three heavy metal ions as adsorption targets,the application of wood vinegar simulated agricultural application method was added to the adsorbents with the saturable heavy metal.The effect of different concentration and appliedamount of the wood vinegar on the adsorption effect of the heavy metal adsorbents was investigated,and the resorption capacity of heavy metal adsorption materials after wood vinegar application was evaluated.As a result,it was found that wood vinegar had a significant effect on the adsorption effect of the heavy metals contained-adsorbents(HCMA).As the concentration of wood vinegar increased,the effect on the adsorption effect of heavy metal adsorbents was different,and the adsorption effect on different adsorption materials and different heavy metal ions was also different.In order to reduce the adverse effect of wood vinegar on the adsorption effect of heavy metal adsorption materials,it was determined that the adverse effect was greatly reduced when the concentration of wood vinegar was lower than 500 dilution times.In addition,the key substances in wood vinegar that affect the adsorption effect of heavy metals were investigated,acetic acid was found to have the greatest effect on the adsorption effect of the adsorbents.Secondly,the effect of wood vinegar on the adsorption properties of heavy metal adsorbents was investigated.Phosphate rock was used as the object of investigation.It was found that the surface morphology of phosphate rock powder changed after being treated with wood vinegar,and its capacity of heavy metal adsorption was significantly improved.Through optimizing the treatment conditions such as dilution ratio,material-liquid ratio and temperature of wood vinegar,it was finally found that wood vinegar under a dilution concentration of 10 times,0.25 g/L material-liquid ratio and 100?water bath for 4 h,the maximum Pb(II)and Cd(II)adsorption capacities of modified phosphate rockwere increased to 76.64%and 14.08%respectively,the specific surface area(7.562 m~2/g)of modified phosphate rock was 5 times higher than unmodified phosphate rock(1.428 m~2/g).The conclusions drawn in this thesis will offer a standadization and guidance of the rational application of wood vinegar in the agricultural field,and provide a high-efficiency reference method for the repair of heavy metal contaminated soil.