中草药渣生物吸附剂制备及其对水环境中污染物吸附性能研究

Adopting the Chinese herbal medicine residues such as liquorice, ephedra as the raw material, and taking the heavy metal ions，anion and dye molecules in the solution as the target, the coordination chemistry, molecule structure theory and adsorption theory as the guidance, the chemical modification as the measurement, the high effective adsorption agent with high capacity was synthesized by the functional unit design with fine measurement, and utilized for the adsorption of the heavy metal ions, anion and dye molecules from aqueous solution and the purification of the waste water. Composition, structure and surface activity functional groups of the adsorbents and their relationship with the species of heavy metal ions, anion and dye molecules in the solution are cleared through the experiment and analysis means, which chemical modification direction and route will be given for Chinese herbal medicine residue. The characteristics of the thermodynamics and kinetics in the adsorption process will be studied to master the feature of the modified bio-adsorption agents and the behaviors & regularity of adsorption. With the ongoing of this project, the multiple purposes may be attained including promoting the effective utilization of the Chinese herbal medicine residues and research and development of the environmentally friendly techniques for wastewater purification and recovery of heavy metal ions, as a new train of thought is provided for the waste material of Chinese herbal medicine full use of, to realize the comprehensive utilization of resources has the economic and environmental significance.

采用废弃物质- - 中草药药渣为基本原料，以水环境中污染物如重金属离子、阴离子和染料分子等为目标对象，以配位化学、分子结构理论和吸附理论为指导，以化学改性为手段，制备吸附容量大的高效生物吸附剂，用于水环境中污染物的环境友好净化。通过实验和分析手段明晰吸附剂组成、结构和表面活性官能团与水溶液中重金属离子、阴离子和染料分子等存在形态的对应关系，明确中草药渣化学改性的方向和路线；研究吸附过程热力学、动力学特征，掌握所制备的中草药渣生物吸附剂的特性以及吸附/解吸的过程行为规律。该项研究的开展，可为废弃物质中草药渣的有效利用和水环境中污染物的治理以及重金属离子净化回收提供理论依据和基础数据，为中草药渣的资源化及深度利用提供一种新的思路，对实现资源综合利用具有经济和环境双重意义。

利用废弃甘草、麻黄和黄芪等中药药渣，经硫酸化、胺化和炭化等方法改性，制备了多种高吸附容量的生物吸附剂，并用于对模拟水溶液中重金属离子(Cu2+、Pb2+、Cd2+、Zn2+、Ni2+)、染料分子（亚甲基蓝、甲基橙、结晶紫、中性红）和小分子污染物（甲苯和苯胺）的吸附。甘草、麻黄和黄芪等药渣经多种方法改性后，表面结构发生了不同程度的改变，表面均变得疏松多孔，比表面积均有不同程度的增大，药渣改性前后的红外光谱图及多种分析测定结果说明化学改性后表面活性官能团数目增加。化学改性一方面改变了药渣基体材料的表面结构，同时改变了表面活性官能团的种类和数目，使改性产物对目标对象—-环境污染物的吸附能力大幅度提高。通过静态吸附实验考察了不同实验因素对吸附过程的影响，研究吸附动力学及热力学。结果表明，改性药渣生物吸附剂对污染物的吸附速度都很快，在3 h内均能达到吸附平衡，吸附动力学均符合准二级动力学方程；对多数污染物的吸附均符合Langmuir和Freundlich模型。改性药渣生物吸附剂对重金属离子、染料分子和小分子污染物的吸附机制，既有吸附剂表面活性官能团与污染物的离子交换和螯合作用，又有药渣炭化后由于发达的孔隙结构和巨大比表面积对污染物的物理吸附作用。甘草、麻黄和黄芪等药渣来源广泛，成本低廉，改性过程操作简单；改性药渣生物吸附剂的制备可以消除或减少中草药渣对环境的污染，使其成为资源，得到充分利用，同时降低水环境污染物处理的成本，环境友好。该课题的开展，为有效利用废弃中草药渣类生物质和各类污染废水净化提供了重要的基础性数据。