Environmentally friendly cellulose waste recycling
AssigneeWashington State University
InventorsHang Liu, Jinwen Zhang, Wangcheng Liu
Life of this patent
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Abstract
Techniques for chemically recycling cellulose waste such as cotton are disclosed herein. In one embodiment, a method includes hydrolyzing a cotton waste and dissolving cellulose in the hydrolyzed cotton waste in an aqueous solution containing an alkali and one or more of urea ((NH2)2CO), polyethylene glycol, or thiourea (SC(NH2)2) to produce another aqueous solution containing dissolved cellulose. Then the another aqueous solution containing the dissolved cellulose can be extruded into a coagulation bath to coalesce the dissolved cellulose in the extruded solution, thereby reforming the dissolved cellulose from the cotton waste into a regenerated fiber.
Claims9
A method for recycling a post-consumer cellulose waste containing cellulose, the method comprising:
- hydrolyzing the post-consumer cellulose waste containing the cellulose such that the cellulose in the hydrolyzed cellulose waste has a degree of polymerization of about 240 to about 860, the post-consumer cellulose waste being discarded after use by consumers;
- dissolving the cellulose in the hydrolyzed post-consumer cellulose waste having the degree of polymerization of about 240 to about 860 in an aqueous solution containing (i) lithium hydroxide (LiOH) and (ii) urea ((NH2)2CO);
- during dissolving the cellulose, maintaining a dissolution temperature setpoint of the aqueous solution between −15° C. to les than 0° C. such that a cellulose solution containing the dissolved cellulose from the post-consumer cellulose waste having a cellulose concentration of about 2% to about 10% by weight is produced;
- and
- extruding the cellulose solution containing the dissolved cellulose into a coagulation bath containing a coagulant configured to coalesce the dissolved cellulose in the extruded solution, thereby reforming the dissolved cellulose from the cellulose waste into a regenerated fiber or film.
A method for recycling a post-consumer cellulose waste containing cellulose, the method comprising:
- hydrolyzing the post-consumer cellulose waste such that the cellulose in the hydrolyzed post-consumer cellulose waste has a degree of polymerization of about 240 to about 860;
- dissolving the cellulose in the hydrolyzed post-consumer cellulose waste having the degree of polymerization of about 240 to about 860 in an aqueous solution containing (i) lithium hydroxide (LiOH) and (ii) urea ((NH2)2CO);
- during dissolving the cellulose, maintaining a dissolution temperature setpoint of the aqueous solution between −5° C. to less than 0° C. such that a cellulose solution containing the dissolved cellulose from the post-consumer cellulose waste having a cellulose concentration of about 2% to about 10% by weight is produced;
- and
- extruding the cellulose solution containing the dissolved cellulose into a coagulation bath containing a coagulant configured to coalesce the dissolved cellulose in the extruded solution, thereby reforming the dissolved cellulose from the cellulose waste into a regenerated fiber or film.
Dependencies are inferred from the claim text.