The pretreatment of miscanthus using ionic liquids; a way for biofuel production

Biomass, as fuel source, is renewable, environmentally friendly and abundant in the natural world. Lignocellulosic biomass is a potential source of renewable energy for transportation fuels through the conversion of fermentable sugars derived from cellulose and hemicelluloses to biofuels. A lignocellulosic material contains up to 35-50% cellulose which is the most abundant biopolymer on the earth and, thus, it is a valuable source of raw materials [1]. The comprehensive utilization of cellulose resources has drawn much attention from the governments and researchers, and there is an increasing demand to develop new technologies to obtain and dissolve cellulose to overcome the drawbacks of traditional pulping and processing methods. Nevertheless, the highly crystalline nature of cellulose, and the presence of lignin surrounding the cellulose microfibrils, contribute to the slow enzymatic hydrolysis of cellulosic biomass and necessitate pretreatment to increase hydrolysis rates. While mechanical milling, weak and strong acid treatment, ammonia fiber expansion, and other pretreatment methods increase hydrolysis rates [2], by far the most effective pretreatment devised so far is the dissolution and subsequent precipitation of cellulose in ionic liquids [3]. Ionic liquids are organic salts, liquids around or below 100°C. These solvents have unique physicochemical properties such as high thermal stability, wide electrochemical window and negligible vapor pressure and so they are considered to be green solvents. They have been suggested to replace volatile organic compounds in industrial separation processes, as well as applications in chemical synthesis, electrochemistry, polymer chemistry and nanotechnology [4]. In the present study, different imidazolium based ionic liquids were used to dissolve miscanthus and extract cellulose with high purity to be easily converted into biofuels. The influence of different parameters such as miscanthus size, miscanthus weight%, temperature, time, precipitant type, water content and the structure of the IL were evaluated. 2 Methods