Hydrothermal Carbonization And Hydrogen Production From Cellulose And Other Biomass In Ionic Liquid

With energy shortages and environmental problems becoming increasinglyprominent, looking for clean and renewable energy to meet the needs of the survivaland development of human society has become a highly concerned research directionand important social issues. Among them, hydrogen production from biomass is aneffective way to obtain green and clean hydrogen energy using renewable biomass.The current methods of producing hydrogen from biomass mostly require harshreaction conditions, such as high temperature and high pressure, which exert highrequirements on the equipment and also lead to high energy consumption. The overallperformance of hydrogen-production is not economic. Therefore, it is of greatnecessity to find a green and economic way of producing hydrogen from biomass tosolve the above problems.Inspired by the existing literatures, which demonstrate that ionic liquid has agood performance of dissolving cellulose and also other biomass and roughly comeup with the mechanism of cellulose degradation in ionic liquid, this article hasdiscussed and explored the likelihood of producing hydrogen from biomass throughone-step at relatively low temperature （～200℃） and also analyzed the factors thatinfluence the yield of hydrogen. Model compounds of biomass, cellulose and glucose,were used as raw materials, the mixtures of ionic liquid [BMIM]Cl and water wereused as a solvent. Besides, titania nanotubes SO₄^2-/TNTs and micro-porous molecularsieve HZSM-5were prepared and modified to be used as solid acid catalyst combinedwith the efficient catalyst of formic acid decomposition, ZnO. Meanwhile，for the firsttime, we realized hydrogen production from biomass and hydrothermal carbonizationof biomass at the same time. While producing hydrogen, we also obtained carbonmicrospheres and carbon nanospheres from biomass.（1） In this study, hydrothermal synthesized TNTs at130℃using nano-TiO2asraw materials were utilized to prepare SO₄^2-/TNTs with H2SO4impregnation and450℃calcinations. Nano-TiO2, TNTs and SO₄^2-/TNTs were characterized using XRD and SEM. Impact of the concentration of H2SO4solution and impregnation time onthe yield of hydrogen was studied.（2） SO₄^2-/TNTs and ZnO were combined to catalyze the production of hydrogenfrom cellulose, glucose and platanus leaves respectively in the mixtures of ionic liquid[BMIM]Cl and water. The experiments examined the influence of several factors,such as catalyst,[BMIM]Cl-H2O ratio, and temperature, on the yield of hydrogen.When cellulose was used as the raw materials, results show that the amount of thecatalyst can make a big difference to the yield of hydrogen. When the amount ofSO₄^2-/TNTs was increased from50mg to150mg, the yield of hydrogen almost tripledto132.33μmol/g/h. Besides, the ratio of [BMIM]Cl and water has a big influence onthe yield of hydrogen, which increases evidently when adding water while decreaseswhen the amount of water is too much.（3）HZSM-5was modified by acid and alkali respectively and then was used tocatalyze hydrogen production from cellulose, glucose and platanus leaves. Whencellulose was used as the raw materials, results show that SO₄^2-/TNTs are morefavorable to hydrogen production from cellulose than molecular sieve HZSM-5. Theyield of hydrogen is increased by60%. However, when using glucose as the rawmaterial, experiment results show that HZSM-5is more favorable. The different Si/Alratio of HZSM-5has different catalyst effect on the reaction of hydrogen production.Lower ratio of Si/Al is better. The catalytic effect of HZSM-5after alkali modificationon hydrogen production performance declined, but it enjoys a longer service life.Compared with cellulose, yield of hydrogen from glucose decomposition is far more,reaching672.5μmol/g/h.（4）Cellulose, glucose, platanus leaves and their residues after producinghydrogen were respectively treated by hydrothermal carbonization.The products werecharacterized by XRD and SEM, from which we can observe the differentmorphologies of carbon materials using different carbonization methods and undervarious carbonization conditions.