高岭土酸碱复合改性制备多孔材料及其应用

PREPARATION AND APPLICATION OF POROUS MATERIALS BY COMBINING BASE AND ACID MODIFICATION OF KAOLIN

采用碱改性及碱改性后进一步酸改性的方式对高温焙烧高岭土进行改性,详细研究了改性方式对改性产物的孔结构及组成的影响。结果表明:随着碱浓度的提高,改性产物的比表面积及孔体积增大,硅铝比[n(SiO_(2))/n(Al_(2)O_(3))]略有减小;随着碱改性次数的增多,改性产物的孔体积出现减小的趋势,而硅铝比增大;碱改性时,高温焙烧高岭土中二氧化硅的溶解促进铝源的活化;对碱改性高温焙烧高岭土进一步作酸改性,可获得孔体积为0.81 cm^(3)/g、比表面积为408 m^(2)/g的多孔材料,以该材料作为催化裂化催化剂载体所制备的催化剂,可使油浆产率减小3.07百分点,汽油收率增大2.68百分点,总液体收率增大2.58百分点。

The effect of modification of fully calcined kaolin with different alkaline concentration,different alkaline treating times,and acid treating of alkaline-leaching fully calcined kaolin was studied in details.The changes in porosity,chemical composition of modified fully calcined kaolin were characterized by XRD,N 2 adsorption-desorption and X-ray fluorescence spectrometer.The results showed that with the increase of alkaline solution concentration,the pore volume and BET surface area of the modified product increased,and the SiO_(2)/Al_(2)O_(3) ratio reduced slightly,but with the increase of alkaline-treated times,the pore volume decreased and SiO_(2)/Al_(2)O_(3) ratio increased.Moreover,the porous material with a pore volume of 0.81 cm^(3)/g and a specific surface area of 408 m^(2)/g could be obtained after alkaline-leaching fully calcined kaolin further modified by acid treating.When using the catalyst prepared from the porous material for catalytic cracking reaction,the slurry yield reduced by 3.07 percentage points,the gasoline yield increased by 2.68 percentage points,and the total liquid yield increased by 2.58 percentage points.