Efficiency,mechanism and ecological risk of removing heavy metals from soils by fermentation broth of agricultural wastes
In this study agricultural wastes such as pineapple peel and cantaloupe peel residue were fermented by adding lactic acid bacteria to produce the high-efficiency and green materials for removing heavy metals from soils,and the removal efficiency,mechanism and ecological risk of cadmium(Cd),lead(Pb)and zinc(Zn)in soils were investigated.Results showed that the removal rates of Cd,Pb and Zn improved by 14.27%-20.76%via washing with fermented eluents.The removal rates of Cd,Pb and Zn increased significantly by increasing of eluent concentration,decreasing of the pH values,and appropriately prolongating of the washing time.Increasing the number of leaching times can effectively remove heavy metals from the soil particles.Interestingly,after three times washing by pineapple peel fermentation broth,the residual Cd and Zn in soils were lower than the limits in the national soil quality standards for agricultural land(GB 15618-2018).Moreover,the environmental risk and bioavailability of Cd and Zn decreased and their stability was enhanced.While the total amount of Pb decreased,its mobility was enhanced.Therefore,fermentation broth from agricultural wastes by inoculating with lactic acid bacteria is an effective and ecofriendly practice for removing of Cd and Zn from soils,and further study on the environmental risk of Pb can be performed.
biomass materialspeel pomacefermentation brothsoil washingheavy metal