A sturdy was carried out on nanofibrillar cellulose from unbleached wood pulp using sulfuric acid and ammonium persulfate for acid-oxidative treatment. The diameter of the fibers of the resultant nanofibrillar cellulose is described by a log normal distribution with maximum at about 11 nm. Nanofibrillar cellulose may be used to modify the surface of paper or cardboard leading to greater mechanical strength and improved barrier properties relative to gas permeability as well as a component of industrial adsorbents.