Modification of lignin with phosphoric-urea mixture and study of its properties

The process of lignin phosphorylation in a medium of phosphoric acid and urea has been studied. The product prepared contains 1.3– 6.8 % phosphorus, 0.3–2.3 % nitrogen and has an ion exchange capacity of 0.7 to 2.8 mg-ekv•g –1 of Na + , to 1.8–2.3 mg-ekv•g –1 with respect to Ni 2+ and 2.6 –2.8 mg-ekv•g –1 to U О 2 2+ . The product of thermal decomposition of lignin phosphate at 500 °C actively absorbs benzene vapor (sorption value of 0.42–0.52 sm 3 •g –1 ) and has a Na + ion exchange capacity of 2.8 mg-ekv•g –1 .