Research And Application Of The Remediation Of V Contaminated Soil With Soil Conditioners And Native Plants

Some human activities(e.g.mining,fuel combustion and steel refining)may cause hundreds of thousands of tons of V to be deposited on land,increasing soil V concentrations and the information concerning on remediation of V-contaminated soils is available.Thus,some soil conditioners,including polyacrylamide(PAM),sepiolite,sludge compost(S C),peat,humic acid(HAC),lime,fly ash,and bentonite,were used in this study for amending V-contaminated soil.Moreover,the effect of soil conditioners on the growth of canola plants or wild ramie and soil characteristics was analyzed for selecting combinations of soil conditioners to be used in field experiment.The results were as follows:On the condition that the mixed ratio between contaminated soil and uncontaminated soil was 1:1 and the mixed soil was immobilized by 1 wt% zero-valent iron(ZVI),pot experiments with canola plants were performed to evaluate the effect of soil conditioners on the growth of canola plants and the uptake,bioaccumulation,and translocation of heavy metals.Tested soil conditioners included polyacrylamide(PAM),sepiolite,humic acid(HAC),peat,sludge compost(SC),bentonite,lime,and fly ash.Results from the analysis of the growth of canola plants and the analysis of variance showed that the best soil conditioners for V-contaminated soil were 0.02–0.1 wt% PAM,1 wt% peat,1 wt% HAC,and 1 wt% SC;Moderately effective soil conditioners included sepiolite and lime;The invalid soil conditioners included fly ash and bentonite.According to screening results for soil conditioners,we proposed three combinations of soil conditioners,such as 0.02 wt% PAM + 1 wt% Sepiolite + 1 wt% SC,0.1 wt%PAM + 1 wt%SC,and 0.02 wt% PAM + 1 wt% SC + 0.2 wt% bentonite.Moreover,the effect of combinations of soil conditioners on the growth of canola plants and wild ramie and their uptake,bioaccumulation,and translocation of heavy metals was analysed.Results showed that the combinations of 0.02 wt% PAM + 1 wt% Sepiolite + 1 wt% SC,and 0.02 wt% PAM + 1 wt% SC + 0.2 wt% bentonite were better than the combination of 0.1 wt%PAM + 1 wt%SC.Field studies were performed after laboratory resrarches.Results from field experiment showed that there was no significant difference effect of between the combination of 0.02 wt% PAM + 1 wt% Sepiolite + 1 wt% SC and the combination of 0.02 wt% PAM + 1 wt% SC + 0.2 wt% bentonite on plant biomass.However,because the price and dosage of sepiolite were higher than bentonite,the combination of 0.02 wt% PAM + 1 wt% SC + 0.2 wt% bentonite was chosen as the best comnination of soil conditioners.Therefore,the combination of 0.02 wt% PAM + 1 wt% SC + 0.2 wt% bentonite was promising for mitigating V contamination in soil.