Method for the preparation of amine-functionalized fibrillated cellulose for reversible CO 2 adsorption from a gas mixture, in particular from exhaust gases or ambient air, with the following steps (i) providing a suspension of fibrillated cellulose and adding a reagent for providing amine functionalities to the fibrillated cellulose; (ii) mixing the resulting suspension for a time span allowing for the formation of a homogeneous suspension of fibrillated cellulose mixed and/or adsorbed and/or reacted with said reagent for providing amine functionalities; (iii) drying the resulting homogeneous suspension from step (ii) resulting in surface amine-functionalized fibrillated cellulose and converting it into granular form with a bulk density of at least 150 kg/m3 (according to ISO 697); wherein either (a) in step (i) a suspension of fibrillated cellulose is provided with a dry mass content of fibrillated cellulose of at least 15% (dry matter content according to SCAN-CM 39:94), wherein the suspension with the active reagent for providing amine functionalities, resulting from step, has a dry mass content of fibrillated cellulose and active reagent for providing amine functionalities of at least 20% (dry matter content according to SCAN-CM 39:94), and wherein step (iii) involves freeze-drying of the surface amine-functionalized fibrillated cellulose or (b) in step (iii) fluidized spray drying is used for at the same time drying and converting into granular form wherein in step (i) per 1g of fibrillated cellulose at least 0.5g of pristine reagent for providing amine functionalities are added and wherein the reagent for providing amine functionalities to the fibrillated cellulose is selected as monoalkyldialkoxyaminosilane in its pristine or hydrolyzed form. (i) providing a suspension of fibrillated cellulose and adding a reagent for providing amine functionalities to the fibrillated cellulose; (ii) mixing the resulting suspension for a time span allowing for the formation of a homogeneous suspension of fibrillated cellulose mixed and/or adsorbed and/or reacted with said reagent for providing amine functionalities; (iii) drying the resulting homogeneous suspension from step (ii) resulting in surface amine-functionalized fibrillated cellulose and converting it into granular form with a bulk density of at least 150 kg/m3 (according to ISO 697); (a) in step (i) a suspension of fibrillated cellulose is provided with a dry mass content of fibrillated cellulose of at least 15% (dry matter content according to SCAN-CM 39:94), wherein the suspension with the active reagent for providing amine functionalities, resulting from step, has a dry mass content of fibrillated cellulose and active reagent for providing amine functionalities of at least 20% (dry matter content according to SCAN-CM 39:94), and wherein step (iii) involves freeze-drying of the surface amine-functionalized fibrillated cellulose or (b) in step (iii) fluidized spray drying is used for at the same time drying and converting into granular form wherein in step (i) per 1g of fibrillated cellulose at least 0.5g of pristine reagent for providing amine functionalities are added and wherein the reagent for providing amine functionalities to the fibrillated cellulose is selected as monoalkyldialkoxyaminosilane in its pristine or hydrolyzed form.