METHOD OF PRODUCING GRAPHENE INK Russian patent published in 2020 - IPC C09D11/52 B82Y40/00 C01B32/194 

FIELD: nanotechnologies.

SUBSTANCE: invention can be used for 2D printing of conductive tracks, RFID-antennas, thin-film supercapacitors, as well as for coloring different fabrics and paper. First, upper humus peat is separated by humic acid by peat decalcification with 10 % HCl solution with subsequent extraction of humic substances from decalcified peat. Separated humic acid is purified by centrifugation for 20 minutes at 5,500 g to remove coarse suspensions with subsequent filtration of the obtained solution through a membrane with pore size of 0.4–0.6 mcm. Purified humic acid is treated with 30 % aqueous ammonia solution until corresponding humates are formed. Obtained solution of water-soluble form of humic acid is mixed in a reactor with an aqueous suspension of graphene oxide with concentration of 5–10 mg/ml. Water-soluble form of humate can also be prepared directly in a suspension of graphene oxide in a reactor. After stirring, 15–20 g of reducing agent of graphene—glucose or ascorbic acid oxide are added to obtained mixture. Then heated to 70 °C and stirred until a black suspension is formed, which is centrifuged. Precipitate is washed with deionised water to remove residues of said reducing agent. Washed up sediment is dispersed in water at ultrasonic irradiation at working frequency 22 kHz, power 600 W and 2,500–20,000 rpm of the disperser inclusively during 10 minutes.

EFFECT: invention enables to obtain graphene ink in an environmentally and biologically safe way.

4 cl, 4 ex