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以棉秆为原料,采用一步磷酸活化法制备了孔径集中在10 nm以内的高比表面棉秆基生物质活性炭吸附材料,利用氮气吸附、红外光谱FT-IR、扫描电子显微镜SEM等技术对制备的棉秆基生物质活性炭表面物化性质进行了分析,并通过BJH方程、DFT密度函数理论及Horvath-Kawazoe方程对制备的活性炭孔结构进行了表征计算,研究了浸渍比、活化温度、活化时间等工艺参数对生物质炭得率、元素组成、孔结构及化学官能团等物化性质的影响,并考察了制备生物质炭对水中以碘、2,4二硝基苯酚、铅(Ⅱ)、亚甲基蓝等不同分子尺寸物质的吸附性能.结果表明,在浸渍比3∶2、活化温度500℃、活化时间2 h的条件下,通过磷酸活化棉秆,能制备出孔径范围分布在10 nm范围内,富含氧酸官能团的高比表面生物质炭,其得率高达47.87%,孔容、比表面积、含氧酸官能团含量分别为0.982 cm3·g-1、1570 m2·g-1、1.43 mmol·g-1,中孔率超过36%,且98%以上的中孔分布在10 nm以内.该窄孔径中孔炭对水中碘、2,4二硝基苯酚、亚甲基蓝与铅(Ⅱ)的吸附值分别为1007、336、153 mg·g-1与121 mg·g-1,表明该棉秆基窄孔径中孔炭对水中不同分子尺寸的物质均具有很好的吸附性能,是一种良好的生物质液相吸附材料.
Using cotton stalk as raw material, one-step phosphoric acid activation method was used to prepare high-surface cotton stalk-based biomass activated carbon adsorbent with pore diameter concentrated within 10 nm. The effects of nitrogen adsorption, FT-IR and SEM The physical and chemical properties of cotton stalk-based biomass activated carbon were analyzed. The pore structure of activated carbon was characterized by BJH equation, DFT density function theory and Horvath-Kawazoe equation. The effects of impregnation ratio, activation temperature and activation time Effects of process parameters on physicochemical properties, such as yield, elemental composition, pore structure and chemical functional groups of biomass, were investigated. The effects of preparation of biomass carbon on iodine, 2,4 dinitrophenol, lead (Ⅱ) and methylene blue The results showed that under the condition of impregnation ratio 3: 2, activation temperature 500 ℃, and activation time 2 h, cotton fiber was activated by phosphoric acid, and the pore diameter distribution was in the range of 10 nm The results showed that the high specific surface area biochar with oxo-acid functional groups had a high yield of 47.87%, the pore volume, specific surface area and oxygen-containing functional groups were 0.982 cm3 · g-1 and 1570 m2 · g -1, 1.43 mmol · g-1, the mesoporosity was above 36%, and the mesopores above 98% were distributed within 10 nm. The mesoporous carbon with narrow pore size was sensitive to iodine, 2,4 dinitrophenol, methylene blue and The adsorption values of lead (Ⅱ) were 1007, 336, 153 mg · g-1 and 121 mg · g-1, respectively. It indicated that the mesoporous carbon with narrow pore size had good adsorption to water with different molecular size Performance, is a good biomass liquid phase adsorbent material.