Synthesis Regulation Of Calcium Ferrite Doped With Praseodymium And Production Of Oxygen-containing Compounds By Catalytic Pyrolysis Of Lignin

The sugar industry produces a large amount of bagasse lignin（BL）,which can be converted into phenolics and other oxygen-containing compounds by chemical treatment.A series of calcium ferrite oxides(Ca_1-xPr_xFeO₃,CPF-x)doped with praseodymium were synthesized by sol-gel method,the calcination mechanism was optimized,the catalytic pyrolysis of BLwas evaluated,and the regeneration performance was investigated.The results are as follows:（1）The optimal parameters for the synthesis and calcination of CPF-x are:x=0.5,p H is about 8.5,n（CA）:n（EDTA）:n（total metal ions）=1.6:1:1,the calcination rate is 4℃?min^-1,under the Oxidation atmosphere,the calcinantion temperature is 800℃,the calcination time is6 h.Under this condition,CPF-0.5 presented a cubic crystal phase with loose porous structure,its specific surface area is 66.65 m²·g^-1.（2）The thermogravimetric results of BL by CPF-0.5 show that CPF-0.5 has a significant catalytic effect on BL.In the catalytic pyrolysis process,the endpoint temperature is reduced by 19℃,and the weight loss rate increases by 5%,which is conducive to the generation of gas and liquid phase products.（3）The optimal process parameters of CPF-0.5 for BL catalytic pyrolysis were:m（CPF-0.5）/m（BL）was 1:3,the pyrolysis temperature was 650℃,and the yield of liquid phase was up to 20.73%,which was mainly syringin,phenol and guaiacol,with a total selectivity of 63.21%.Using CPF-0.5 as catalyst,the selectivity of syringin compounds increased from 20.60%to 29.59%,and the selectivity of some monophenol compounds in BL catalytic pyrolysis was improved.（4）The synthesis of CPF-0.5 was regulated by template agent（Cetyl trimethyl ammonium bromide（CTAB）,Sodium dodecyl benzene sulfonate（SDBS）and TWEEN-20）.When the template agent was SBDS,the catalytic pyrolysis of BL was better than that under the catalyst prepared by other template agents,with the liquid yield of 24.6%and the selectivity of phenolic compounds of 66.47%.When the addition of SDBS increased to a certain level(0.1 mol?L^-1),the yield of the liquid phase product was 26.76%.The selectivity of phenolic compounds was 83.67%.（5）The characteristic peak of CPF-0.5 did not change after catalytic pyrolysis-cyclic regeneration reaction,and the crystal phase of CPF-0.5 remained unchanged.The selectivity of liquid product after catalytic regeneration did not change significantly,indicating that CPF-0.5 still had good reactivity and structural stability.