鸡血藤药渣对废水中Cu^(2+)的吸附行为

Adsorption of Cu^(2+) from wastewater by a residue of production of a Chinese medicine from Spatholobus suberectus Dunn.

采用废弃中药渣鸡血藤(Spatholobus suberectus Dunn.,SSD)为生物吸附剂对废水中铜离子(Cu^(2+))进行吸附,探讨吸附性能和吸附机理,为废水中Cu^(2+)的去除和中药渣的资源化利用提供参考依据。通过吸附性能试验探讨了吸附剂剂量、pH值、初始离子浓度、温度、时间和共存阳离子对SSD吸附Cu^(2+)的影响,根据吸附前后SSD的形貌特征,探讨其对Cu^(2+)的吸附机理。结果表明,SSD对Cu^(2+)的吸附速率较大,在30 min时吸附达到平衡。增加吸附剂剂量、pH值和吸附时间均会促进SSD对Cu^(2+)的吸附,共存阳离子会在一定程度上抑制Cu^(2+)的吸附。Sips等温模型能更好地描述不同温度下SSD对Cu^(2+)的吸附过程,吸附特征是Langmuir和Freundlich模型的结合。SSD对Cu^(2+)的吸附符合准二级动力学方程,表明化学吸附是反应的限速步骤。SSD对Cu^(2+)的吸附机理包括离子交换、络合和静电吸引。研究表明,废弃中药渣鸡血藤可用于废水中Cu^(2+)的去除。

The aim of this study is to examine the efficacy of a byproduct of production of a Chinese medicine from Spatholobus suberectus Dunn.(SSD)as an adsorbent to remove Cu^(2+)from polluted water.These studies of adsorption capacity and adsorption mechanism offer insights into a new means for Cu^(2+)removal from contaminated water,and enhance resource utilization related to production of a Chinese medicine.Variables affecting Cu^(2+)removal efficiency,including SSD dose,pH value,initial ion concentration,temperature,time,and coexisting cations,were investigated by adsorption performance tests.The results showed the adsorption rate of SSD for Cu^(2+)was fast,and adsorption reached equilibrium after 30 min.The Cu^(2+)adsorption mechanism was addressed by examining SSD morphological characteristics before and after adsorption.Cu^(2+)adsorption by SSD was improved with increasing SSD dose,pH value,and time,while coexisting cations inhibited Cu^(2+)removal to a certain degree.The Cu^(2+)adsorption data fit the Sips model well,suggesting that Cu^(2+)adsorption on SSD occurs by a combined Freundlich–Langmuir model.The Cu^(2+)removal mechanism includes ion exchange with Ca^(2+)and Mg^(2+),chelating with SSD surface functional groups,and electrostatic attraction between cationic Cu^(2+)and negative charges on SSD.In conclusion,SSD can be used for Cu^(2+)removal from wastewater.