Li Kunquan, Wan Zeqing
College of Engineering, Nanjing Agricultural University;
College of Engineering, Nanjing Agricultural University.
J Vis Exp. 2019 Feb 12(144). doi: 10.3791/58161.
An environment-friendly technique for synthesizing biomass-based mesoporous activated carbon with high nitrogen-/oxygen-chelating adsorption for Cu(II) is proposed. Bagasse impregnated with phosphoric acid is utilized as the precursor. To pyrolyze the precursor, two separate heating modes are used: microwave pyrolysis and conventional electric-heating pyrolysis. The resulting bagasse-derived carbon samples are modified with nitrification and reduction modification. Nitrogen (N)/oxygen (O) functional groups are simultaneously introduced to the surface of activated carbon, enhancing its adsorption of Cu(II) by complexing and ion-exchange. Characterization and copper adsorption experiments are performed to investigate the physicochemical properties of four prepared carbon samples and determine which heating method favors the subsequent modification for doping of N/O functional groups. In this technique, based on analyzing data of nitrogen adsorption, Fourier transform infrared spectroscopy, and batch adsorption experiments, it is proven that microwave-pyrolyzed carbon has more defect sites and, therefore, time-saving effective microwave pyrolysis contributes more N/O species to the carbon, although it leads to a lower specific surface area. This technique offers a promising route to synthesis adsorbents with higher nitrogen and oxygen content and a higher adsorption capacity of heavy-metal ions in wastewater remediation applications.
提出了一种环境友好型技术，用于合成对Cu(II)具有高氮/氧螯合吸附性能的生物质基介孔活性炭。以浸渍磷酸的甘蔗渣为前驱体。为了对前驱体进行热解，采用了两种不同的加热方式：微波热解和传统电加热热解。对所得甘蔗渣衍生的碳样品进行硝化和还原改性。将氮（N）/氧（O）官能团同时引入活性炭表面，通过络合和离子交换增强其对Cu(II)的吸附。进行表征和铜吸附实验，以研究四种制备的碳样品的物理化学性质，并确定哪种加热方法有利于后续N/O官能团掺杂的改性。在该技术中，基于氮吸附、傅里叶变换红外光谱和批量吸附实验的数据分析，证明微波热解碳具有更多的缺陷位点，因此，省时高效的微波热解为碳贡献了更多的N/O物种，尽管它导致比表面积较低。该技术为在废水修复应用中合成具有更高氮和氧含量以及更高重金属离子吸附容量的吸附剂提供了一条有前景的途径。
