One-step synthesis of renewable magnetic tea-biochar derived from waste tea leaves for the removal of Hg0 from coal-syngas. Issue 4 (August 2021)

• Record Type: Journal Article
• Authors: Altaf, Adnan Raza; Teng, Haipeng; Zheng, Maoshen; Ashraf, Imtiaz; Arsalan, Muhammad; Rehman, Ata Ur; Gang, Liu; Pengjie, Wang; Yongqiang, Ren; Xiaoyu, Li
• Is Part Of: Journal of environmental chemical engineering. Volume 9:Issue 4(2021)
• Publication Date: 2021-08
• Subjects: Mercury removal -- Magnetic sorbent -- Regeneration -- Waste management -- Coal gasification; Chemical engineering -- Environmental aspects -- Periodicals; Environmental engineering -- Periodicals; Chemical engineering -- Environmental aspects; Environmental engineering; Periodicals; 660.0286
• DOI: 10.1016/j.jece.2021.105313
• Languages: English
• ISSNs: 2213-2929

Abstract

Abstract: Elemental mercury (Hg 0 ) is becoming more alarming toxic pollutant due to its high persistence in the environment. However, advanced oxidation/adsorption techniques could be the major routes of Hg 0 removal by a suitable adsorbent. For this purpose, a highly competitive and regenerable magnetic tea biochar (MTBC) was developed by one-step pyrolysis of Fe(NO3 )3 laden waste tea leaves at 500 ℃ and characterized by analytical techniques such as BET, XRD, VSM, SEM, TGA, and XPS. The Hg 0 removal mechanism via adsorption/oxidation from simulated syngas was investigated under a wide reaction temperature range (60 ℃–300 ℃). Results revealed that the MTBC with an optimal loading of 0.46 mol/L Fe(NO3 )3, attained an approximately ≥ 95% of Hg 0 removal efficiency (η T ) at 180 ℃ under simulated syngas (10% CO, 10% H2, and 400 H2 S). The TBCFe 0.46 exhibited high H2 O resistance under simulated syngas, although a slight decrease was received in η T at 10 vol% H2 O. After six repeated adsorption/regeneration cycles, the η T value was still above 90%. Consequently, the waste tea derived regenerable sorbent TBCFe 0.46 with high Hg 0 adsorption performance makes it an inexpensive, excellent recyclable catalyst to control mercury emission from coal syngas. Graphical Abstract: ga1 Highlights: A low-cost magnetic sorbent was prepared by facile method to capture gaseous Hg 0 . TBCFe 0.14 showed high Hg 0 removal performance up to ~96% at 180 ℃. H2 S had a significant role for capturing Hg 0 from simulated syngas over TBCFe 0.46 . After six frequent adsorption/regeneration sets Hg 0 removal efficiency was ≥ 90%.