Animal charcoal for efficiently fixing heavy metals and preparation method and application thereof

Abstract

The invention relates to animal charcoal for efficiently fixing heavy metals and a preparation method and application thereof. A calcium / phosphorus / carbon complex, namely the animal charcoal obtainedby anoxic pyrolysis of animal carcasses or animal organs or animal tissues has relatively-high calcium and phosphorus contents and a low carbon content, and has main components of hydroxyapatite and amorphous carbon. The animal charcoal can efficiently fix a variety of heavy metal contaminants, and exhibits different fixing mechanisms for different heavy metal ions. Pb(II) interacts with the hydroxyapatite to form a phosphate precipitate; Cd(II) or Cu(II) can interact with the hydroxyapatite to undergo cation exchange; while Hg(II) is easily adsorbed on the surface of elemental carbon for reduction. The maximum adsorption capacities of the animal charcoal to the Pb(II), Cd(II), Cu(II) and Hg(II) reach 3.10, 0.89, 1.17 and 0.36 mmol / g respectively. Compared with the prior art, the animal charcoal has the advantages of greenness, environmental friendliness, remarkable adsorption and fixation effects on the various heavy metals, and good promotion and application prospects.

Description

technical field [0001] The invention belongs to the field of in-situ restoration of heavy metal pollution, in particular to an animal charcoal for fixing heavy metals with high efficiency and a preparation method and application thereof. Background technique [0002] Biochar is a kind of porous carbon material obtained by low temperature pyrolysis of environmental biomass, which is widely used in the field of heavy metal pollution remediation. Biochars prepared from different raw materials have very different properties and exhibit different potentials for heavy metal remediation. For example, biochar prepared from straw has high silicon content and low carbon content, which is not good for heavy metal fixation. Woody biochar is rich in carbon elements, has a large specific surface area, and is rich in surface functional groups, which can adsorb heavy metals through electrostatic interaction, ion exchange, surface complexation, etc.; but these effects are partially reversib...

AI Technical Summary

Problems solved by technology

Although the specific surface area is small, the carbonate and phosphate components in fecal charcoal can combine with heavy metals through precipitation, etc., especially the formed phosphate precipitates (such as chlorphosphonite, Pb 5 (PO 4 ) 3 Cl) has very low solubility and is very effective for heavy metal immobilization

However, there are some problems in the application of fecal charcoal: the water content of fresh feces is high (62%-87%), and the pyrolysis process requires more heat; the content of heavy metals is high, and it has the potential to become a source of heavy metal pollution; Phosphorus content is not high (generally less than 3.3%), there is no advantage over natural high phosphorus content restorative materials

[0007] Both of the above two patents require pretreatment of bones such as impurity removal and crushing, and the process of roasting or carbonization is relatively complicated.

In addition, the above two patents are all about the carbonization of bones, and impurities (such as meat, tissue or gelatin on the bones) need to be removed. Simultaneous carbonization of meat, tissue or gelatin cannot be achieved, resulting in animal meat, tissue, etc. Or colloids, etc. are not well utilized

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