摘要
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.
Mesoporous activated carbon with pore width less than 10 nm was prepared with cotton stalk as raw materials and H3PO4 as activating agent by one step carbonization method. The property and pore structure of the carbon was characterized by nitrogen adsorption, infrared spectroscopy （FTIR） and scanning electron microscopy （SEM）. Main pore characteristics of activated carbon were analyzed by BET equation, Horvath- Kawazoe BET method and D＆F method. Effects of impregnation ratio, carbonization temperature and heat preservation time on the yield, elemental composition and adsorptive capacity of activated carbon were studied. The adsorption capacity of the prepared activated carbon for iodine, 2,4-dinitrophenol, lead （ lI ） and methylene blue was studied. The optimized preparation conditions are as follow ： impregnation ratio of 3 ： 2, activation temperature of 500 ~C and activation time of 2 h. The BET surface area of the activated carbon prepared from cotton stalk reach 1570 m2. g-1 when its total pore volume, mesoporous percentage, yield, iodine number and methylene blue adsorption are 0. 982 cm3- g-1, 36.9% , 47.87% , 1007 mg. g-1 and 153 mg·g-1 under above conditions. More than 98% of mesopores in the prepared carbon was within in 10 nm size. Both methylene blue adsorption and iodine number are much better than that of the first grade product specified in the National Standard. The Langmuir maximum adsorption capacities of lead （ 11 ） and 2,4- dinitrophenol on the carbon are 121 mg.g-1 and 336 mg.g-1 The results showed that the prepared carbon was a good adsorbent with high adsorption capacity for different organic pollutants.
出处
《环境化学》
CAS
CSCD
北大核心
2013年第11期2134-2141,共8页
Environmental Chemistry
基金
国家自然科学基金(51102136)
教育部博士点基金(20110097120021)资助
关键词
窄孔径
棉秆
孔结构
官能团
吸附性能
biomass-based carbon, preparation, pore structure, functional group, adsorption capacity.
