化工进展 ›› 2020, Vol. 39 ›› Issue (4): 1558-1566.DOI: 10.16085/j.issn.1000-6613.2019-1123

• 资源与环境化工 • 上一篇    下一篇

改性高岭土捕集CdCl2、PbCl2蒸气

樊聪慧(),黄亚继(),夏志鹏,查键锐,于梦竹,丁守一,胡华军,戚二兵   

  1. 东南大学能源热转换及其过程测控教育部重点实验室,江苏 南京 210096
  • 收稿日期:2019-07-15 出版日期:2020-04-05 发布日期:2020-04-28
  • 通讯作者: 黄亚继
  • 作者简介:樊聪慧(1996—),女,硕士研究生,研究方向为固废资源化处理。E-mail:3043694872@qq.com
  • 基金资助:
    国家重点研发计划(2018YFB0605100);国家自然科学基金(51676040);江苏省自然科学基金(BK20181281)

Adsorption capacity of modified kaolin for gaseous CdCl2 and PbCl2

Conghui FAN(),Yaji HUANG(),Zhipeng XIA,Jianrui ZHA,Mengzhu YU,Shouyi DING,Huajun HU,Erbing QI   

  1. Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education,Southeast University, Nanjing 210096, Jiangsu, China
  • Received:2019-07-15 Online:2020-04-05 Published:2020-04-28
  • Contact: Yaji HUANG

摘要:

针对两种重金属氯化物PbCl2、CdCl2,探究高岭土表面羟基对吸附重金属的作用。对高岭土进行煅烧及水热改性,并在两段式管式炉上进行高岭土捕集重金属氯化物蒸气实验,并使用原子吸收分光光度计(AAS)测量吸附剂中的重金属氯化物含量。吸附数据表明对于PbCl2及600~700℃的CdCl2吸附,高岭土经过煅烧吸附效率大幅降低,水热重新赋予羟基后吸附效率有所提升,但仍低于原高岭土。结合热重(DTG)及红外谱图(FTIR)分析可知,高岭土经800℃煅烧脱除全部羟基,经水热重新获得部分羟基,且所获数量随水热程度的加深而增多,结合XRD谱图可知羟基促进了高岭土与重金属氯化物的吸附反应;800℃以上高温下原高岭土吸附效率逐渐低于煅烧高岭土和水热高岭土,结合核磁共振谱图(NMR)分析可知其原因在于,高岭土经煅烧改性及水热改性,Al原子配位数降低,活性增强,更易与重金属氯化物蒸气结合。

关键词: 重金属蒸气, 吸附剂, 吸附作用, 高岭土, 煅烧改性, 水热改性

Abstract:

Kaolin was modified by calcination and hydrothermal reaction. The differential thermogravimetry (DTG) and infrared spectrum(FTIR) results of kaolin showed that kaolin loses all of hydroxyl group after calcination for 3h at 800℃, and regained some hydroxyl group by hydrothermal reaction. The nuclear paramagnetic resonance (NMR) results of kaolin showed that calcined kaolin and hydrothermal kaolin had lower Al atomic coordination number and higher activity than original kaolin. Then the adsorption efficiency of kaolin and modified kaolin for PbCl2 and CdCl2 at different temperatures was studied during incineration in tubular furnance. Atomic absorption spectrometer (AAS) was used to detect the distribution of PbCl2 and CdCl2 in the kaolin. The experiment and XRD results showed that the adsorption efficiency of kaolin for PbCl2 at 600—900℃ and CdCl2 at 600—900℃ met the regulation of original kaolin>hydrothermal kaolin>calcined kaolin, which indicated that the adsorption of kaolin for PbCl2 and CdCl2 was enhanced by oxhydryl. However, when the temperature exceeded 800℃, the adsorption efficiency of original kaolin was lower than that of calcined kaolin and hydrothermal kaolin, which indicated that oxhydryl had no effect on the adsorption of kaolin for PbCl2 and CdCl2. Besides, calcination and hydrothermal modification may promote the adsorption by enhancing Al atomic activity.

Key words: heavy metal vapor, adsorbents, adsorption, kaolinite, calcination modification, hydrothermal modification

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