Cellulose Aggregation under Hydrothermal Pretreatment Conditions.
Cellulose, the most abundant biopolymer on Earth, represents a resource for sustainable production of biofuels. Thermochemical treatments make lignocellulosic biomaterials more amenable to depolymerization by exposing cellulose microfibrils to enzymatic or chemical attacks. In such treatments, the solvent plays fundamental roles in biomass modification, but the molecular events underlying these changes are still poorly understood. Here, the 3D-RISM-KH molecular theory of solvation has been employed to analyze the role of water in cellulose aggregation under different thermodynamic conditions. The results show that, under ambient conditions, highly structured hydration shells around cellulose create repulsive forces that protect cellulose microfibrils from aggregating. Under hydrothermal pretreatment conditions, however, the hydration shells lose structure, and cellulose aggregation is favored. These effects are largely due to a decrease in cellulose-water interactions relative to those at ambient conditions, so that cellulose-cellulose attractive interactions become prevalent. Our results provide an explanation to the observed increase in the lateral size of cellulose crystallites when biomass is subject to pretreatments and deepen the current understanding of the mechanisms of biomass modification.
Institute of Chemistry, University of Campinas , Caixa Postal 6154, Campinas, São Paulo 13083-970, Brazil.
Rodrigo L
RL
Silveira
National Institute for Nanotechnology , 11421 Saskatchewan Drive NW, Edmonton, Alberta T6G 2M9, Canada.|Department of Chemical and Materials Engineering, University of Alberta , 9107 - 116 Street, Edmonton, Alberta T6G 2 V4, Canada.|Department of Mechanical Engineering, University of Alberta , 4-9 Mechanical Engineering Building, Edmonton, Alberta T6G 2G8, Canada.|CanmetENERGY-Devon, Natural Resources Canada, 1 Oil Patch Drive, Devon, Alberta T9G 1A8, Canada.
Stanislav R
SR
Stoyanov
National Institute for Nanotechnology , 11421 Saskatchewan Drive NW, Edmonton, Alberta T6G 2M9, Canada.|Department of Mechanical Engineering, University of Alberta , 4-9 Mechanical Engineering Building, Edmonton, Alberta T6G 2G8, Canada.
Andriy
A
Kovalenko
Institute of Chemistry, University of Campinas , Caixa Postal 6154, Campinas, São Paulo 13083-970, Brazil.
Munir S
MS
Skaf
D018533:Biomass; D002482:Cellulose / Q000737:chemistry*; D006358:Hot Temperature; D012997:Solvents / Q000737:chemistry*; D013816:Thermodynamics; D014867:Water / Q000737:chemistry*
D012997:Solvents; D014867:Water; D002482:Cellulose