High-carbon recovered paper and plastic materials with reduced endotoxin levels
Provided herein are composite materials comprising at least 70 wt. % thermally consolidated recovered paper and plastic fragments and less than 5,000 ng water-soluble endotoxin per gram of composite materials, as well as methods of preparing said composite materials and methods of sanitizing recovered waste materials.
1. A method to prepare a composite material, the method comprising:
compressing and heating a mixture comprising paper fragments or plastic fragments, or a combination thereof, and a multifunctional aldehyde to form the composite material;
wherein the composite material comprises polymerization product of the multifunctional aldehyde; cross-linked endotoxin; and at least about 70 wt. % of the paper fragments or the plastic fragments, or the combination thereof.
2. The method of claim 1 , wherein the polymerization product of the multifunctional aldehyde is present in the composite material in an amount of about 0.01 wt. % to about 0.40 wt. %; and the cross-linked endotoxin is present in the composite material in an amount of about 0.0001 wt. % to about 0.02 wt. %.
3. The method of claim 1 , wherein the multifunctional aldehyde is selected from the group consisting of malondialdehyde, succinic dialdehyde, glutaraldehyde, phthalaldehyde, or a combination of two or more thereof.
4. The method of claim 1 , wherein the multifunctional aldehyde is at least partially in the form of a urea-aldehyde adduct.
5. The method of claim 4 , wherein the urea-aldehyde adduct has a molar ratio of urea to multifunctional aldehyde of less than about 1.
6. The method of claim 1 , wherein the method further comprises treating an initial mixture comprising the paper fragments or the plastic fragments, or the combination thereof, with the multifunctional aldehyde.
7. The method of claim 6 , wherein the initial mixture is treated with the multifunctional aldehyde in an amount of about 200 ppm to about 4,000 ppm.
8. The method of claim 6 , wherein the multifunctional aldehyde is applied to the initial mixture as a pre-formed solution of a urea-aldehyde adduct.
9. The method of claim 6 , wherein the method further comprises treating the initial mixture with urea concomitantly with the multifunctional aldehyde.
10. The method of claim 6 , wherein the method further comprises treating the initial mixture with an odor blocker, a biocide, an insecticide, or a combination of two or more thereof.
11. The method of claim 6 , wherein the method further comprises conditioning the initial mixture at about standard pressure for at least 5 minutes after the treating step but prior to compressing and heating to form the composite material.
12. The method of claim 11 , wherein the conditioning is performed at room temperature or at a temperature of about 50° F. to about 90° F.
13. The method of claim 6 , wherein the method further comprises sorting recovered waste materials to obtain the initial mixture; wherein the paper fragments or the plastic fragments, or the combination thereof, comprise gram-negative bacteria.
14. The method of claim 13 , wherein the paper fragments or the plastic fragments, or the combination thereof, of the initial mixture further comprise one or more fungi.
15. The method of claim 1 , wherein the method further comprises forming the mixture into a mat prior to compressing and heating the mixture.
16. The method of claim 1 , wherein the compressing and heating are conducted at a temperature of at least 200° F.
17. The method of claim 1 , wherein the compressing and heating are conducted for at least 1 minute.
18. The method of claim 1 , wherein the composite material further comprises less than about 5,000 ng of water-soluble endotoxin per gram of composite material.
19. The method of claim 1 , wherein the paper fragments or the plastic fragments, or the combination thereof, are present in the composite material in an amount of about 70 wt. % to about 99 wt. %.
20. The method of claim 1 , wherein the paper fragments or the plastic fragments, or the combination thereof, are recovered from one or more waste streams selected from municipal solid waste, materials recycling facility residuals, post-commercial waste, and construction and demolition waste.