水稻秸秆和椰壳生物质碳对菲的吸附动力学对比

以水稻秸秆为前驱物质,在700 ℃高温条件下酸处理制备含灰分和去除灰分的2种水稻秸秆生物质碳吸附剂; 对这2种生物质碳的内部结构与表面形态进行粒度与扫描电镜显微观察与分析,并与椰壳生物质碳进行对比; 然后,以菲为目标污染物,采用批处理试验方法,系统考察上述3种生物质碳对菲的吸附性能及其结构特征的异同。结果表明:酸处理制成的去除灰分水稻秸秆生物质碳有效提高了比表面积、孔容与碳含量; 水稻秸秆生物质碳对菲的吸附能力很强,并且吸附率很快,在1 min内吸附率就可达到70%; 上述3种生物质碳对菲的吸附能很好地遵循伪二级动力学方程,而且伪二级吸附速率常数随菲初始质量浓度的增大而逐渐减小,说明其主要受颗粒内部扩散控制。由此可见,酸处理水稻秸秆生物质碳是一种理想的污染土壤修复材料。

Comparison of Adsorption Kinetics of Rice Straw and Coconut Shell Biomass Carbons to Phenanthrene

Rice straw as precursor matter was pyrolyzed at 700 ℃ to prepare rice straw biomass carbons with and without ash; internal structure and surface morphology of the two kinds of rice straw biomass carbons were shown by SEM and particle size analysis, and were compared with that of coconut shell biomass carbon; taking phenanthrene as the target contaminant, the adsorption of the three kinds of biomass carbons to phenanthrene was analyzed systemically, and the difference of structure characteristics was discussed. The results showed that rice straw biomass carbon without ash treated by acid efficiently improved the specific surface area, pore volume and carbon content; the adsorption of biomass carbons to phenanthrene was stronger, and the adsorption rate was fast and reached to 70% within 1 min; the adsorption of the three kinds of biomass carbons to phenanthrene followed pseudo-second-order kinetics equation, and rate constant of the equation gradually decreased with the increase of initial mass concentration of phenanthrene, so that the rate was mainly controlled by particle internal diffusion. In general, rice straw biomass carbon treated by acid was an ideal material for the remediation of contaminated soil.