Research Of Optimization Treatment Of Lignocellulose Materials And Application Of Catalytic Ozonation Technology

Fuel ethanol produced by lignocellulose as raw material is of an effective way in which people can solve energy and environmental issues,and maintain social development.With straw as raw material of a model plant,acid and alkali pretreatment of raw material were studied under atmospheric conditions.there are no relevant studies in catalytic ozonation technology with ozone applied to straw pretreatment.Firstly,staw powder was handled with dilute sulphuric acid under normal pressure,the optimal disposal conditions of lignocellulose were studied by the single factors and L₉(3⁴) orthogonal tests,with total reducing sugar in treatment solution as optimization index and analyzed through SPSS 13.0 as follow:solid-liquid ratio 1:10, sulphuric acid concentration 25%,reaction temperature 95℃,reaction time 3h, effects orders of every factor on sulphuric acid were:reaction temperature＞sulphuric acid concentration＞solid-liquid ratio＞reaction time.reaction temperature was highly significant factor,sulphuric acid concentration was significant factor,solid-liquid ratio had a certain impact on results,reaction time had no impact among investigation range.The total reducing sugar content in treatment solution of lignocellulose was 2.704g, total reducing sugar yield was 94.9%.The changes of constituent contents of lignocellulose were:cellulose content 64.53%,loss percentage 8.84%,hemicellulose content 2.54%,loss percentage 95.06%,lignin content 10.35%, degradation percentage 20.39%.Secondly,staw powder was handled with sodium hydroxide under normal pressure,the optimal disposal conditions of lignocellulose were studied by the single factors and L₉(3⁴) orthogonal tests,with cellulose loss percentage,hemicellulose loss percentage,lignin degradation percentage respectively as optimization index.The results were integrated evaluation as follow:solid-liquid ratio 1:12,alkali concentration 25%,reaction temperature 55℃,reaction time 3h,effects orders of every factor on alkali treatment were:alkali concentration＞reaction temperature＞reaction time＞solid-liquid ratio. reaction temperature and alkali concentration was significant factor,reaction time ratio had a certain impact on results,solid-liquid had no impact among investigation range.The changes of constituent contents of lignocellulose were:cellulose content 66.43%, loss percentage 3.63%,hemicellulose content 15.10%,loss percentage 69.89%,lignin content 2.32%,degradation percentage 89.21%.The integrated evaluations of two methods showed:reaction conditions disposaled by sodium hydroxide were milder,and had a lower cost price compared with sulphuric acid.The microscopic morphology of straw surface handled by two methods Through SEM showed:the specific surface of lignocellulose was enhanced after handled by the two methods,but the effect of sodium hydroxide was bigger.Non-TiO₂/Silica-gel catalyzed ozonation of lignocellulose from straw was studied.TiO₂/Silica-gel as catalyst was prepared through sol-dipping,the results of precursor analyzed byTG-DTA and non-TiO₂/Silica-gel by SEM showed non-TiO₂ which calcinated at 500℃was anatase which cohered on Silica-gel surface more uniform.non-TiO₂/Silica-gel as catalyst,solid-liquid ratio 1:12 fixed,reaction time 2 h, changes of every constituent content of samlpers handled towards different catalyzed ozonation conditions showed:proper catalyst was 10 g·L^-1,sodium hydroxide concentration and reaction temperature were 1%and 25℃respectively,the results of catalyst used repeatly showed:change of cellulose loss percentage was very small, hemicellulose loss percentage and lignin degradation percentage were both decreasing, accompanied the frequencies multiplication.The microscopic morphology of straw lignocellulose surface catalyzed ozonation Through SEM showed:straw lignocellulose external surface had obvious crack,had polygonal mesh pore space inside.Kinetics of degradation lignocellulose catalyzed ozonation by non-Non -TiO₂/Silica-gel was discussed.The results showed:under temperature range of 5～45℃,process coincidenced first order Kinetics.Fitting calculated by empirical formula k=A·e^-Ea/RT,Ea =20.132 kJ/mol.The mechanism of degradation of non-Non -TiO₂/Silica-gel was analyzed,the external surface of OH and TiO₂ could initiated chain type decomposition to get·OH,OH^- concentration maybe the common influencing factor on·OH productions by two different pathways.