Preparation Of Magnetic Solid Acid Catalysts Based On Biomass And Research On The Cellulose Hydrolysis With It

Lignocellulose is recognized as the only one that can be fixed carbon and renewable energy in energy industry, develops to use lignocellulose as carbon-based materials, and based on its surface activation treatment to prepare biomass based magnetic solid acid catalyst have been to become the hottest research topics and cutting-edge technologies in the field of catalyst.So, the preparation of biomass based magnetic solid acid catalyst has the extremely important significance for the development of new sources of energy, national energy security and reduce environmental pollution and so on.This paper through analyzed different biomass raw materials, and selected to corn straw as raw material to prepare biomass based solid acid catalyst. In order to get optimum process conditions of preparation of biomass based solid acid catalyst, first of all, adopts the Design-Expert 8.0.6 software Design, Box-Behnken model, and then utilized carbonization time, carbonization temperature, sulfonated time and sulfonated temperature to design response surface experiment of four factors three levels, the reducing sugar yield which come from preliminary catalytic hydrolysis corn straw demonstrated the performance of catalyst. The optimum process conditions of preparation of biomass based solid acid catalyst(biomass based precursor) was Optimized: carbonization temperature 549°C, carbonization time 13 h,sulfonated temperature 121°C, sulfonated time 6h, using biomass based precursor to hydrolysis corn straw, the corn straw of conversion rate 8.82%, the reducing sugar yield for 7.97%,predictive value for 7.98% with predicted values differ 0.01% and the repeatability is good.The optimized condition of biomass based magnetic solid acid catalyst preparation was get that calcining temperature 500°C, calcination time 3h, the proportion of biomass based precursor and magnetic Fe3O4 particles is 1:2. Using biomass based magnetic solid acid catalyst to catalytic hydrolysis of cellulose, the reducing sugar yield 58.8%, cellulose conversion ratio at 65%. Utilized advanced analysis methods such as XRD, TEM, SEM, FTIR,EA, BET to analyze the channel structure and functional group of biomass based magneticsolid acid catalyst. The results show that the magnetic Fe3O4 particles successfully load on the biomass based precursor. The diffraction peak of two obvious prominent weaker and width, at the same time, biomass based magnetic solid acid catalyst with disordered carbon structure was got by high angle further polymerization. There are a large number of sulfonic acid group in the catalyst structure, enhance the catalytic activity and stability of the catalyst; At the same time, the catalyst has larger specific surface area, improves the dispersion of catalyst in the cellulose hydrolysis reaction, make its contact with cellulose molecules fully. Recycling to use the catalyst hydrolysis microcrystalline cellulose after three times, due to the sulfonic acid group has been lost in catalyst structure lead to its active declined, but the active of catalyst can be regenered by using the method of sulfonated again; at the same time, due to the presence of magnetic particles, the catalyst is easy to be recovered.The test also preliminary studied on microwave assisted biomass based magnetic solid acid catalysts catalytic hydrolysis of cellulose, with hydrolysis time, hydrolysis temperature,ratio of cellulose and catalyst content, microwave power as test factors to optimize the best process conditions of cellulose hydrolysis. The best process conditions: hydrolysis time 25 min,hydrolysis temperature 80°C, ratio of cellulose and catalyst content 1:2.5, microwave power450 W, the primary and secondary order of four factors effect on cellulose hydrolysis:Microwave power > ratio of cellulose and catalyst contain > hydrolysis time > hydrolysis temperature. Under the best conditions, the yield of reducing sugar was 57.4%. Microwave assisted biomass based magnetic solid acid catalyst to catalysis cellulose hydrolysis, not only solve the problem of cellulose difficult to soluble in water, effectively also improve effect of cellulose hydrolysis, have played an important role in saving resources, obtained the high yield of reducing sugar; after heating, cellulose hydrolysis can avoid the No security problems which to cause by high temperature and pressure.