Chemical Industry and Engineering Progress ›› 2023, Vol. 42 ›› Issue (7): 3875-3883.DOI: 10.16085/j.issn.1000-6613.2022-1631

• Resources and environmental engineering • Previous Articles     Next Articles

Leaching mechanism of Hg-absorption products on CeO2/TiO2 sorbentsin syngas

LU Yang(), ZHOU Jinsong(), ZHOU Qixin, WANG Tang, LIU Zhuang, LI Bohao, ZHOU Lingtao   

  1. State Key Laboratory of Clean Energy Utilization,Zhejiang University, Hangzhou 310027, Zhejiang, China
  • Received:2022-09-05 Revised:2022-12-13 Online:2023-08-14 Published:2023-07-15
  • Contact: ZHOU Jinsong

CeO2/TiO2吸附剂煤气脱汞产物的浸出规律

陆洋(), 周劲松(), 周启昕, 王瑭, 刘壮, 李博昊, 周灵涛   

  1. 浙江大学能源清洁利用国家重点实验室,浙江 杭州 310027
  • 通讯作者: 周劲松
  • 作者简介:陆洋(1998—),男,硕士研究生,研究方向为煤气脱汞。E-mail:22027011@zju.edu.cn
  • 基金资助:
    国家自然科学基金(52176136)

Abstract:

In view of the requirements of the subsequent innocuity treatment of metal oxide adsorbents for mercury removal, a brand-new idea of leaching Hg-absorption products from metal oxide using sodium thiosulfate (Na2S2O3) solution was proposed in this paper. Mercury-containing adsorbents (Hg-CeTi) was obtained by CeO2/TiO2 sorbents (CeTi) after mercury adsorption. Mercury temperature-programmed desorption (Hg-TPD) was used to determine the occurrence form of adsorbed-Hg on the surface of Hg-CeTi. Then, the extraction capacity of Na2S2O3 solution on the Hg-absorption products from the Hg-CeTi was studied, and the migration mechanism of mercury with different occurrence forms in Na2S2O3 solution was emphatically analyzed. The results of Hg-TPD showed that HgCl2, HgO and HgS were the main Hg-adsorption products in the syngas. HgO was easy to desorb from Hg-CeTi and migrate to the liquid phase due to the coordination ability of thiosulfate (S2O32-) with Hg2+. HgCl2 reacted with OH- in the liquid phase to form HgO, which was subsequently leached by Na2S2O3 solution. For two different crystalline forms of HgS, the increase in the concentration of Na2S2O3 solution could promote the migration of HgS (black) to the liquid phase, but it had a slight effect on the HgS (red) due to the stability of HgS (red). After leaching in 1.0mol/L Na2S2O3 solution for 1h, the mercury leaching rate could reach 97.3%, and the remaining mercury existed in stable HgS form.

Key words: leaching, mercury, adsorbents, stability, syngas, waste treatment

摘要:

基于金属氧化物脱汞吸附剂后续无害化处理要求,本文提出采用硫代硫酸钠(Na2S2O3)溶液浸出金属氧化物脱汞产物的新思路。CeO2/TiO2吸附剂(CeTi)吸附汞后得到含汞吸附剂(Hg-CeTi),利用汞程序升温脱附实验(Hg-TPD)确定其表面吸附态汞的赋存形态。随后探究Na2S2O3溶液对于Hg-CeTi表面脱汞产物的浸出能力,着重分析不同赋存形态的汞在Na2S2O3溶液中的迁移规律。Hg-TPD结果表明,模拟煤气中脱汞产物以HgCl2、HgO和HgS为主。由于硫代硫酸根(S2O32-)与Hg2+的配合能力,HgO易从Hg-CeTi表面脱附并向液相迁移;HgCl2会在液相中与OH-反应生成HgO,再被Na2S2O3溶液浸出;对于两种不同晶型的HgS,提高Na2S2O3溶液浓度可促进HgS(black)向液相迁移,但对于更稳定的HgS(red)收效甚微。在1.0mol/L的Na2S2O3溶液中浸出1h后,汞浸出率可达97.3%,且剩余的汞以稳定的HgS形态存在。

关键词: 浸出, 汞, 吸附剂, 稳定性, 合成气, 废物处置

CLC Number: 

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