Preparation method of duckweed charcoal loaded nano zero-valent iron and method of repairing Pb pollutant soil

Abstract

The invention relates to a preparation method of duckweed charcoal loaded nano zero-valent iron and a method of repairing Pb pollutant soil. The preparation method comprises the steps: duckweed is pretreated and then placed in a pyrolytic reaction container, a muffle furnace is set to be in an oxygen limiting environment, the temperature and the pyrolytic time are set, natural cooling and sievingare conducted after the pyrolytic reaction is completed, and duckweed charcoal fine powder is prepared; ferric salt is dissolved into deionized water; a certain amount of absolute ethyl alcohol is added; the duckweed charcoal fine powder is added into the mixed solution; a magnetic stirrer is used for continuous and uniform stirring, dropwise adding of a certain amount of potassium borohydride solution at a constant speed under the protection of nitrogen is then carried out, aging is carried out for 1-2 hours after dropwise adding, washing with deoxygenated water and absolute ethyl alcohol formultiple times respectively is carried out under the protection of nitrogen, and after freeze-drying, storing in an oxygen-free environment in a sealed manner is carried out. When the soil polluted by Pb is repaired, the composite product of the duckweed charcoal and the nanometer zero-valent iron is injected into the soil polluted by the Pb, the bioavailability of the Pb in the soil can be obviously reduced, and the polluted soil is repaired.

Description

technical field [0001] The invention relates to the field of remediation of heavy metal polluted soil, in particular to a method for remediating Pb polluted soil with duckweed biochar loaded with nanometer zero-valent iron. Background technique [0002] According to the "National Soil Pollution Survey Bulletin" jointly issued by the Ministry of Environmental Protection and the Ministry of Land and Resources on April 17, 2014, it shows that my country's soil environment is not optimistic; The proportions of moderately and heavily polluted sites were 11.2%, 2.3%, 1.5% and 1.1%, respectively. The main type of pollution is inorganic type, followed by organic type. The exceeding rate of lead points is 1.5%, the heavy metal Pb pollution problem cannot be ignored, and soil remediation work is urgently needed. [0003] In the prior art, for heavy metal Pb pollution, nanometer zero-valent iron is mostly used for remediation treatment. The essence of nano-zero-valent iron (EZVI) is ...

AI Technical Summary

Problems solved by technology

[0007] The purpose of the present invention is to provide a duckweed biochar-loaded nano-zero-valent iron for the problems of poor repair effect on non-aqueous phase pollutants in groundwater described in the background technology, large consumption of oxidants, and low repair efficiency. Method for Remediating Pb Contaminated Soil