# US 10,501,690 B2 · Soil heavy metal composite passivator and its preparation method, use method and application > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,501,690 B2 - Document ID: US10501690B2 - Status: Granted - Kind: B2 - Application number: 16/181,037 - Filed: 2018-11-05 - Published: 2019-05-16 - Granted: 2019-12-10 - Earliest claimed: 2017-11-15 - Assignees: Chinese Research Academy of Environmental Sciences - Applicants: Chinese Research Academy of Environmental Sciences - Inventors: Yonghai Jiang; Xinying Lian; Beidou Xi; Yu Yang; Xu Han; Huan Huan; Fu Xia - Web page: https://patentgrep.com/patent/US10501690B2 ## CPC - C09K 17/44: the inorganic compound being cement - B09C 1/08: chemically - B09C 2101/00: In situ - C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE - B09C: RECLAMATION OF CONTAMINATED SOIL (gatherers for removing stone or the like from the soil A01B43/00; sterilising soil by steam A01G11/00; removing undesirable matter, e.g. rubbish, from the land E01H15/00) ## Abstract A soil heavy metal composite passivator and its preparation method, use method and application. The passivator is a powder particle obtained mainly by mixing modified palygorskite, biomass charcoal, quicklime and fungus residue in a mass ratio of 1:(0.3˜0.5):(0.5˜0.8):(0.2˜0.4), with an average particle size of 0.5˜1 mm. The invention further provides preparation and use methods for the above soil heavy metal composite passivator. The soil heavy metal composite passivator according to the invention can effectively passivate heavy metal pollution in farmland soil and reduce bioavailability of various heavy metals in soil so as to recover ecological and industrial functions of the soil and improve crop quality. Material selected in the present invention are safe and environmental-friendly, realized “waste control by waste itself”, have long service life, and do not cause secondary pollution to soil. ## Claims ### Claim 1 A soil heavy metal composite passivator obtained mainly by mixing modified palygorskite, biomass charcoal, quicklime and fungus residue uniformly in a mass ratio of 1:(0.3˜0.5):(0.5˜0.8):(0.2˜0.4). ### Claim 2 (depends on 1) The soil heavy metal composite passivator according to claim 1, wherein the modified palygorskite is obtained by modifying palygorskite through a silane coupling agent; the said biomass charcoal is obtained by pressurized pyrolysis of poultry feathers; the fungus residue is obtained by composting a medium obtained from cultivation of edible fungi. ### Claim 3 (depends on 1) The soil heavy metal composite passivator according to claim 1, wherein the passivator is in the form of powder particles with an average particle size of 0.5˜1 mm. ### Claim 4 (depends on 2) The soil heavy metal composite passivator of claim 2, where the silane coupling agent is chloropropyltrimethoxysilane. ### Claim 5 (depends on 1) A method for remediating heavy metal-polluted soil, the method comprising treating the heavy metal-polluted soil with soil heavy metal composite passivator of claim 1. ### Claim 6 (depends on 5) The method of claim 5 wherein treating the heavy metal-polluted soil comprise: mixing the soil heavy metal composite passivator with heavy metal-polluted soil uniformly in a mass ratio of 1:(10˜50) to provide a contaminated soil mixture; adding water to the contaminated soil mixture so that the water retention rate was 60˜65%; whereby, after 5˜30 days of reaction, heavy metal ions in the contaminated soil mixture are converted into more stable organic bound and residual forms. ### Claim 7 A method for preparing a soil heavy metal composite passivator, comprising: mixing palygorskite modified through a coupling agent, biomass charcoal obtained by pyrolysis, quicklime, and composted fungus residue uniformly in a mass ratio of 1:(0.3˜0.5):(0.5˜0.8):(0.2˜0.4). ### Claim 8 (depends on 7) The method according to claim 7, wherein preparing of the modified palygorskite comprises steps of: (1) immersing palygorskite in an acid solution, filtering and drying; (2) under protection of N2, subjecting the dried palygorskite to coupling reaction in an organic solution containing a silane coupling agent; (3) filtering the resultant, washing with an organic solvent and drying, and then, pulverizing into particles with an average particle size of 0.5˜1 mm for use. ### Claim 9 (depends on 7) The method according to claim 7, wherein preparing of the biomass charcoal comprises steps of: (1) placing pretreated poultry feathers in a crucible for compacting, sealing and pressurized pyrolysis, wherein the poultry feathers are selected from one or more of chicken feathers, duck feathers and goose feathers; (2) crushing the pyrolysis resultant into particles with an average particle size of 0.5˜1 mm for use. ### Claim 10 (depends on 7) The method according to claim 7, wherein preparing of the fungus residue comprises steps of: (1) composting and decaying a medium obtained from cultivation of edible fungi; (2) drying and pulverizing the decayed compost into particles with an average particle size of 0.5˜1 mm for use. ### Claim 11 (depends on 10) The method according to claim 10, wherein in the step (1), during a first period of composting, compost is turned over once a day; thereafter, during a later second period of composting, the compost is turned over once every 2˜3 days; and water is sprayed for the compost material while it is turned over each time so as to keep the moisture content at 60˜65%.