Zhou Qiaoyan,Liu Huan,Wang Yipeng,Xiao Kangxin,Yang Guangyan,Yao Hong
Volatile organic compounds have posed a serious threat to the environment and human health, which require urgent and effective removal. In recent years, the preparation of porous carbon from biomass waste for volatile organic compounds adsorption has attracted increasing attention as a very cost-effective and promising technology. In this study, porous carbon was synthesized from orange peel by urea-assisted hydrothermal carbonization and KOH activation. The role of typical components (cellulose, hemicellulose, and lignin) in pore development and volatile organic compounds adsorption was investigated. Among the three components, hemicellulose was the major contributor to high porosity and abundant micropores in porous carbon. Higher hemicellulose content led to more abundant −COOR, amine-N, and pyrrolic/pyridonic-N in the derived hydrochar, which were favorable for porosity formation during activation. In this case, the toluene adsorption capacity of the porous carbon improved from 382.8 to 485.3 mg·g −1 . Unlike hemicellulose, cellulose reduced the >C=O, amine-N, and pyrrolic/pyridonic-N content of the hydrochar, which caused porosity deterioration and worse toluene adsorption performance. Lignin bestowed the hydrochar with slightly increased −COOR, pyrrolic/pyridonic-N, and graphitic-N, and reduced >C=O, resulting in comparatively poor porosity and more abundant micropores. In general, the obtained porous carbon possessed abundant micropores and high specific surface area, with the highest up to 2882 m 2 ·g −1 . This study can provide guidance for selecting suitable biomass waste to synthesize porous carbon with better porosity for efficient volatile organic compounds adsorption.
Conforming to the principles of green chemistry and sustainable environmental progress, this work demonstrated the concept of “treating waste with waste”, i.e. treating atmospheric pollutant sulfur dioxide (SO 2 ) with agricultural waste of tangerine peel. SO 2 electro-catalytic oxidation is the key technique in this endeavor, which utilizes SO 2 as reaction raw material in the anode to remove it. The anodic SO 2 electro-catalytic oxidation could be coupled to the cathodic hydrogen evolution to achieve the simultaneous SO 2 removal and hydrogen production. Anodic catalyst plays a vital role in this SO 2 transformation. In this work, tangerine peel has been re-utilized to afford tangerine peel-derived biochar (TPB) to prepare TPB/CNT-derived Fe 3 C/Fe/C (N-doped) as a capable anodic catalyst to achieve this goal. With help of various characterization techniques and electrochemical testing, the optimal iron mass fraction and pyrolysis temperature were found to be 16 wt% Fe under 800 °C, with carboxylated carbon nanotube as carbon additive. Transmission electron microscopy (TEM) image showed that the as-prepared TPB/CNT-derived Fe 3 C/Fe/C (N-doped) featured a unique morphology to encapsulate Fe 3 C/Fe with a layer of protecting carbon, which should contribute to the enhanced electro-catalytic performances. A flow electrolyzer was also assembled to illustrate practical application of the anodic catalyst in the real scenario. Owing to its lower cost, the as-prepared TPB/CNT-derived Fe 3 C/Fe/C (N-doped) will be advantageous to replace precious metals to mediate SO 2 electro-catalytic oxidation as one of promising environmental treatment techniques in the future.
危险品化学品经营许可证（带存储）