The effect of ionic strength and pH on the dewatering rate of cellulose nanofibril dispersions

Abstract Cellulose nanofibrils, CNFs, show great potential in many application areas. One main aspect limiting the industrial use is slow and energy demanding dewatering of CNF suspensions. Here we investigate with a piston press process. Three different grades were dewatered to solid contents between approx. 20 30%. The varied charge density (30, 106 604 µmol/g) fibrillation degree. chemical conditions by changing salt concentration (NaCl) pH rates compared before after these changes. For original suspensions, higher provides slower substantially slowest for highest charged CNFs. However, it as fast two lower even though salt/acid additions also improved rate Finally, tuning conditions, could be obtained only minor effect on film properties (strength oxygen barrier) produced from redispersed dispersion. gives some reduction viscosity dispersions. This may disadvantage if e.g. rheology modifier or emulsion stabilizer. Graphical abstract