Abstract:
This paper deals with the adsorption of heavy metal ions on the surface of carbonaceous materials obtained via the chemical activation of biomass. Waste plum stones, pine sawdust and horsetail herb were used as the precursors of carbonaceous adsorbents. The effect of the precursor type and preparation procedure on the physicochemical properties of activated biocarbons and their sorption abilities towards Pb(II) and Cu(II) ions have been checked. The obtained micro-mesoporous activated biocarbons were characterized by determination of elemental composition and ash content, the number of surface functional groups and pH of water extracts as well as textural study based on low temperature nitrogen adsorption/desorption and scanning electron microscopy. Additionally, the electrokinetic studies including solid surface charge density and zeta potential determination were performed. Moreover, the adsorption data modelling (equilibrium and kinetics), XPS results analysis and comparison of parameters characterizing electrical double layer formed at the solid-liquid interface enabled the specification of the mechanism of heavy metals binding with the activated biocarbons surface. The maximum adsorption capacity towards copper and lead ions (177.5 and 178.1 mg/g, respectively) was found for plum stone-based activated biocarbon. For all carbonaceous materials, better fit to the experimental data was achieved with a Langmuir isotherm than a Freundlich one. In turn, a better fit of the kinetics data was obtained using the pseudo-second order model.
摘要:
本文研究了通过生物质化学活化获得的碳质材料表面对重金属离子的吸附。废李子石,松木木屑和马尾草本植物被用作碳质吸附剂的前体。已检查了前体类型和制备程序对活化生物碳的物理化学性质及其对Pb(II)和Cu(II)离子的吸附能力的影响。通过元素组成和灰分含量的测定对获得的微介孔活化生物碳进行了表征,水提取物的表面官能团数量和pH值以及基于低温氮吸附/解吸和扫描电子显微镜的结构研究。此外,进行了包括固体表面电荷密度和zeta电位测定在内的电动研究。此外,吸附数据建模(平衡和动力学),XPS结果分析和表征在固-液界面处形成的双电层的参数的比较使重金属与活化的生物碳表面结合的机理得以规范。对铜和铅离子的最大吸附容量(177.5和178.1mg/g,分别)发现了基于李子石的活性生物碳。对于所有含碳材料,Langmuir等温线比Freundlich等温线更好地拟合实验数据。反过来,使用伪二阶模型获得了更好的动力学数据拟合。