碳纳米管
相(物质)
化学工程
液相
废物管理
材料科学
气相
色谱法
化学
有机化学
纳米技术
工程类
热力学
物理
作者
Chengxin Wang,Wenchao Zhang,Dingding Yao,Qiang Hu,Haiping Yang
标识
DOI:10.1016/j.cej.2024.153725
摘要
The preparation of carbon nanotubes (CNTs) by catalytic pyrolysis of waste plastics is one of the most promising technologies to realize the harmless and high-value recycling of waste plastics. However, there are limited studies on the purification of waste-derived carbons, which is of significance for downstream applications. In this paper, the effects of different gas-phase purification conditions (temperature, gas type), liquid-phase purification (hydrochloric and nitric acid reflux), and combined gas-liquid purification on the properties of CNTs prepared from waste plastics were investigated. The as-obtained and purified CNTs were characterized using SEM, TEM, TPO, XRD, XPS, Raman spectroscopy, and FTIR spectroscopy. Results showed that operational temperatures have distinct impacts on the properties of CNTs during gas-phase purification. An appropriate temperature range for gas-phase purification was determined, with temperatures around 450 °C for air, 650 °C for CO2, and 700 °C for steam respectively, so that the amorphous carbon could be removed and the graphitization of CNTs was retained. Approximately 93 wt% of the metal catalyst particles could be removed with acid treatment for 4 h. In addition, carboxyl and hydroxyl functional groups were introduced to CNTs after acidic treatment. Furthermore, it was found that the approach combining CO2 treatment and nitric acid washing yielded CNTs with relatively higher quantities and lower defect levels. Results showed the properties of CNTs varied from the purification methods, which could meet different needs based on the downstream specific application requirements.
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