(3d) Nanotechnology for Biofuels

Uncertainty in the oil supply, and the environmental issues associated to the utilization of fossil fuels have motivated the interest to produce bio-ethanol as transportation fuel. Most of the ethanol produced in the US comes from the saccharification and fermentation of grains such as corn. Corn is a staple and its use a fuel generates food security concerns. In order to meet the government’s goal of producing 35 million gallons of renewable fuel per year by 2035, about 20 million gallons of lignocellulosic ethanol should be produced per year. The production of ethanol cellulosic faces significant challenges. The structure and chemical composition of lignocellulosic biomasses makes these materials highly resistant to saccharification. Pretreatment of the biomass is required to make it susceptible to enzymatic hydrolysis. Mineral acids along with physical and thermal treatments can increase the digestibility of lignocellulosic materials to a high degree. The use of harsh chemicals demands for corrosion resistant materials, besides neutralization and waste disposal costs. Severe treatments can degrade the sugars to degradation products such as levulinic acid, hydroxyl-methyl-furfural, formic acid and furfural; these compounds can compromise the enzymatic hydrolysis and the fermentation of the carbohydrates because of their inhibitory character. Solid acids have effectively been utilized in commercial applications. Nanoparticles are the latest breakthrough in hetero-catalysis. Nanocatalysts have large surface areas for reaction, they can be recovered from reaction streams, and reused. Some research efforts have being made on the synthesis and characterization of acid-functionalized nanoparticles; however, effective acid nano-catalysts have yet to be developed. Acid-functionalized nanoparticles could be used to catalyze the pretreatment of lignocellulosic biomass; with the advantage that these catalysts could be recycled and reused.