METHOD OF MODIFYING SORBENTS BASED ON CELLULOSE FOR EXTRACTING HEAVY METAL IONS FROM AQUEOUS SOLUTIONS Russian patent published in 2025 - IPC B01J20/24 B01J20/32 C02F1/28 C02F1/62 

FIELD: chemistry.

SUBSTANCE: invention relates to chemical industry and specifically to methods of extracting heavy metal ions by sorption on natural cellulose-containing sorbents. Modification of polymer sorbents based on cellulose is carried out by applying oxidised carbon nanotubes (CNT) on them. Polymer sorbent is obtained in the form of macroporous cellulose beads by dissolving microcrystalline cellulose in an aqueous solution containing 8-10 wt.% NaOH and 7-9 wt. % of urea, at 8-10 °C for 5-7 minutes. Calcium carbonate is then added, mixed and added dropwise into an oil phase containing sunflower oil, Tween-80, Span-80 and sodium laureth sulphate in weight ratio of 750:1:5:8. Suspension is stirred at 60-80 °C for 1.5-2.5 hours. Then 5 wt.% hydrochloric acid solution with subsequent washing of microspheres with ethyl alcohol and distilled water to pH 6. Further, dipropylene glycol, 3 M NaOH solution and epichlorohydrin are added to the microspheres. Microspheres are then washed with distilled water, dried and treated with an aqueous dopamine solution at pH 5-5.5 for 20-24 hours.

EFFECT: higher degree of extraction of heavy metal ions.

1 cl, 1 tbl, 5 ex