Study On The Preparation And Catalytic Performance Of Carbon-based Solid Acid Derived From Waste Paper

In this dissertation,a novel carbon-based solid acid has been successfully prepared from waste paper with pyrolysis or hydrothermal carbonization methods.Also,the influence of preparation conditions on the catalytic and textual features of the prepared catalyst were systematically explored.Moreover,the technological conditions of the catalyzed hydrolysis of cellulose were optimized.and the reuse performance of the catalyst was tested.The optimum conditions for preparing the waste paper carbon-based solid acid catalyst by pyrolysis carbonization approach were determined through condition experiments.which were carbonization temperature 4500C,carbonization time 4 h.sulfonation temperature 100?,sulfonation time 10 h.Under these conditions,the total acid and sulfonic acid amounts of the catalyst were 6.05 mmol/g and 0.96 mmol/g,respectively.And the carbonization and sulfonation temperature have a great influence on the structure and acidity of carbon-based solid acids prepared by pyrolysis method by Fourier transform infrared spectroscopy(FT-IR)and X-ray diffraction spectroscopy(XRD).Then the reaction conditions of the hydrolysis of cellulose were,optimized.The optimal reaction conditions were as follows:the amount of catalyst 0.2 g,the reaction temperature 150?,time 6 h.the addition of water 10 mL.The yield of hydrolyzed cellulose reduced sugar was 56.24%under the optimal reaction conditions.The optimum conditions for preparing the waste paper carbon-based solid acid catalyst by hydrothermal carbonization approach were determined through condition experiments,which were carbonization temperature 240?.carbonization time 4 h.sulfonation temperature 90?,sulfonation time 4 h.Under this condition,the total acid and sulfonic acid amounts of the catalyst were 6.24 mmol/g and 1.26 mmol/g.And the carbonization temperature,time and sulfonation temperature have a great influence on the structure and acidity of carbon-based solid acids prepared by hydrothermal method by FT-IR and XRD.Then the reaction conditions of the hydrolysis of cellulose were optimized.The optimal reaction conditions were as follows:the amount of catalyst 0.25 g,the reaction temperature 160?,time 4 h,the addition of water 10 mL.The yield of hydrolyzed cellulose reduced sugar was 62.04%under the optimal reaction conditions.The surface with honeycomb and fold of the carbon-based solid acid catalyst prepared by pyrolysis was characterized by scanning electron microscopy(SEM).The surface area of the carbon-based solid acid catalyst was 278.9 m2/g by specific surface area(BET).And the surface of the carbon-based solid acid catalyst prepared by hydrothermal method is a granular fragment with a smaller specific surface area of 5.4 m2/g.The structure and properties of waste paper were changed by FT-IR and XRD after sulfonation of incompletely carbonized waste paper during pyrolysis and hydrothermal process.Both of them consist of polyaromatic hydrocarbons and a small proportional of aromatic and alphatic hydrocarbons with SO3H,COOH,and OH functional groups.The thermal stability of the carbon-based solid acid catalyst prepared by pyrolysis was better than that prepared by hydrothermal method by thermogravimetric analysis(TG).Through the re-use of the catalyst experiments can be seen,the stability and reusability of carbon-based solid acid catalysts prepared by pyrolysis are better.