Experiment and Kinetic Study of Elemental Mercury Adsorption over a Novel Chlorinated Sorbent Derived from Coal and Waste Polyvinyl Chloride

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• 作者：Yang Xu ; Xiaobo Zeng ; Bi Zhang ; Xianqing Zhu ; Mengli Zhou ; Renjie Zou ; Ping Sun ; Guangqian Luo ; Hong Yao
• 刊名：Energy & Fuels
• 出版年：2016
• 出版时间：December 15, 2016
• 年：2016
• 卷：30
• 期：12
• 页码：10635-10642
• 全文大小：486K
• ISSN：1520-5029

文摘

This paper describes the synthesis of a novel chlorinated sorbent through one-step pyrolysis of waste polyvinyl chloride (PVC)/coal blends and its application for elemental mercury removal. The effects of pyrolysis temperature (600, 700, 800 °C) and mixing ratio (9:1, 3:1) on Hg⁰ adsorption efficiency was tested in a laboratory-scale fixed bed reactor. For sorbents T8C9P1 and T83P1, a complete removal of mercury was maintained for 30 min at 140 °C. Ion chromatography (IC) analysis, Brunauer–Emmett–Teller (BET) surface area, and X-ray photoelectron spectroscopy (XPS) analysis were used to characterize the sorbents. The results suggested that co-pyrolysis of PVC and coal could fix the pernicious element to a certain extent, leading to a few percent reduction of Cl emission (2.6–13.3%). The XPS and temperature-programmed-desorption (TPD) data showed that parts of the C–Cl functional group were converted into ionic Cl during the Hg⁰ adsorption process, which indicated that the C–Cl bond is the major active component for mercury removal via chemisorption. The adsorption kinetics analysis demonstrated that the elemental mercury adsorption on chlorine-modified sorbent was mainly controlled by chemisorption, and the effect of intraparticle diffusion became apparent after an elapsed time of 25 min. Most C–Cl bonds were assumed to be formed when high molecular weight carbon free radicals and HCl (or Cl free radical) appeared synchronously during co-pyrolysis. Based on the results, the co-pyrolysis of PVC and coal is a multifunctional process for Cl fixation and satisfies the requirements for the synthesis of candidate mercury sorbent.