高酸度芦苇活性炭的制备及其吸附性能

为实现湿地植物资源化,解决重金属废水难处理问题,本文采用青贮活化法制备高酸度湿地植物质活性炭作为吸附材料去除废水中重金属离子镍Ni(Ⅱ)和镉Cd(Ⅱ),通过XRD、N2吸附/脱附、Boehm滴定和元素分析等表征方法,探究湿地植物在青贮过程中结构变化,以及高酸度活性炭比表面积、孔径结构、官能团数量及表面元素。通过批次实验,研究活性炭对重金属离子镍和镉吸附特性,用Langmuir和Freundlich模型对实验数据进行拟合。结果表明:青贮活化法能够有效地提高活性炭的表面酸度,从而提升对重金属离子的吸附能力。通过吸附实验,高酸度活性炭对Ni(Ⅱ)和Cd(Ⅱ)的吸附过程可以用Langmuir模型进行很好的描述,并且活性炭对重金属离子的吸附过程主要由化学吸附控制。

Preparation and Adsorption Performances of Phragmites australis Activated Carbon with High Acidity

For removal of heavy metals from wastewater and recycling the wetland plants, the present study investigated the viability of using silage of Phragmites australis(PA)to prepare activated carbons(ACs)with high acidity. BET surface area, porous texture and surface functional characteristics of ACs were analyzed by N2 adsorption/desorption, elemental analysis and Boehm titration method. ACs presented well-developed micro-porosity and favorable surface acidity. The sorption equilibrium data for Ni(Ⅱ)and Cd(Ⅱ)sorption onto ACs were analyzed by the Langmuir and Freundlich models. The Langmuir model was fitted well to the adsorption behavior. The properties of high surface acidity promoted the adsorption of heavy metals by the silage-treated ACs and the chemical sorption played the key role in the sorption process.