Adsorption and recovery of nonionic polymers by neutralization of cellulose fiber surface charge via cationic polyamide-epichlorohydrin resins

摘要

Nonionic copolymers, such as poly(1-vinylpyrrolidone)-polystyrene, have been used in the production of filtration membranes, catalysts, and sensors. However, their nonionic character and high solubility in water prevents their efficient recovery from waste streams. Cellulose fibers show potential as recovery agents because they are inexpensive, environmentally friendly, and have a large surface area per unit mass. However, due to the anionic nature of the cellulose fiber surface, their adsorptive behavior is often limited to cationic species. We have shown that low-dosage application of a cationic polyamide- epichlorohydrin resin can alter the fiber surface charge so as to provide more neutral surface area for the nonionic polymer to adsorb; furthermore, the adsorbed polyamideepichlorohydrin resin does not block the approach of poly(1-vinylpyrrolidone)-polystyrene. Single-component adsorption of poly(1-vinylpyrrolidone)-polystyrene was on the order of 10~(-3) g/g; with polyamide-epichlorohydrin resin adsorbed on the fiber, the adsorption increased oneorder of magnitude to 10~(-2) g/g. We believe this significant increase is caused by neutralization of fiber surface charge via polyamide-epichlorohydrin resin, creating a surface more favorable for adsorption and recovery of nonionic species.