METHOD OF MODIFYING CELLULOSE-CONTAINING SORBENTS FOR EXTRACTION OF HEAVY METAL IONS FROM AQUEOUS SOLUTIONS Russian patent published in 2020 - IPC B01J20/32 C02F1/28 

FIELD: technological processes.

SUBSTANCE: invention relates to methods of modifying natural cellulose-containing sorbents. Method envisages two-step treatment of material selected from cotton or wood pulp, short flax fiber, wood shavings or girasol stems. At the first step, treatment is carried out with a solution of an oxidising agent selected from sodium metaperiodate, iodic acid or sodium hypochlorite, with concentration of oxidant of 0.1–0.3 M, with solution pH 2.5–4.5, with a solution / sorbent module of 15–50, while heating. At the second step, treatment is carried out with a solution / sorbent module of 15–50 at room temperature. At the first step, the sorbent is treated with an oxidant to contain aldehyde groups in sorbent 10–12 % for 2–4 hours at temperature of 40–55 °C. At the second stage, oxidised sorbent is treated with 3–10 % H-acid solution at solution pH 7.5–10.5 for 60–90 minutes.

EFFECT: high degree of extraction of heavy metal ions from aqueous solutions by the obtained sorbent.

1 cl, 1 tbl, 5 ex