METHOD FOR MODIFYING POLYSACCHARIDE SORBENTS FOR EXTRACTION OF HEAVY METAL IONS FROM AQUEOUS SOLUTIONS Russian patent published in 2021 - IPC B01J20/30 B01J20/24 C02F1/28 C02F1/62 C02F101/20 

FIELD: chemical treatment.

SUBSTANCE: invention relates to methods for modifying natural polysaccharide sorbents intended for the extraction of heavy metal ions by sorption from solutions of various compositions formed as a result of different technological processes, and can be used to improve membrane and sorption technologies, in water treatment, in the development of technologies for the utilization of heavy metal ions from aqueous solutions and wastewater of various nature. In the method for modifying polysaccharide sorbents for the extraction of heavy metal ions from aqueous solutions, which provides for two-stage treatment of the sorbent with modifying agents followed by washing with water after each stage, the first stage is treated with an oxidizer solution at an oxidizer concentration of 0.1-0.3 M, a solution pH of 2.5-4.5 and a solution/sorbent module of 15-50 for 2-4 hours at a temperature of 40-55°C to the content of aldehyde groups in the sorbent of 10-12%, and in the second stage, the treatment of the oxidized sorbent is carried out with a 3-10% solution of 1-amino-8-hydroxynaphthalene-3.6-disulfonic acid at a pH of 7.5-10.5 for 60-90 minutes at a solution/sorbent module of 15-50 at room temperature, and according to the invention, potassium metaperiodate is used as an oxidizer, and chitosan is used as a sorbent, which after two-stage treatment is dissolved in acetic acid and mixed for 20-30 minutes, followed by ultrasound treatment for 10-20 minutes and swelling at rest without stirring for 30-40 minutes, then, the modified sorbent is drip-injected into an aqueous solution of sodium tripolyphosphate with a concentration of 0.05 M with stirring, the resulting microspheres are kept in it at room temperature for 2-4 hours, followed by their separation and thorough washing with distilled water from the unreacted sodium tripolyphosphate.

EFFECT: increased degree of extraction of heavy metal ions from aqueous solutions.

1 cl, 1 tbl, 5 ex