Enabling efficient and economical degradation of PCDD/Fs in MSWIFA via catalysis and dechlorination effect of EMR in synergistic thermal treatment

Yang Xue; Tongyuan Yang; Xiaoming Liu; Zhen Cao; Jiarui Gu; Yanlong Wang

doi:10.1016/j.chemosphere.2023.140164

Enabling efficient and economical degradation of PCDD/Fs in MSWIFA via catalysis and dechlorination effect of EMR in synergistic thermal treatment

Chemosphere. 2023 Nov:342:140164. doi: 10.1016/j.chemosphere.2023.140164. Epub 2023 Sep 12.

Authors

Yang Xue¹, Tongyuan Yang², Xiaoming Liu³, Zhen Cao², Jiarui Gu², Yanlong Wang²

Affiliations

¹ State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing, 100083, China; School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing, 100083, China.
² School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing, 100083, China.
³ State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing, 100083, China; School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing, 100083, China. Electronic address: liuxm@ustb.edu.cn.

PMID: 37709059
DOI: 10.1016/j.chemosphere.2023.140164

Abstract

Catalytic thermal treatment is an efficient and low-energy consumption method for degrading polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in municipal solid waste incineration fly ash (MSWIFA). However, catalysts with high activity are expensive, difficult to separate and reuse from the treated MSWIFA, and they usually pose a risk of heavy metal pollution. Herein, a synergistic thermal treatment method of MSWIFA and electrolytic manganese residue (EMR) at relatively low temperatures was proposed after an in-depth analysis of their mineralogy composition to achieve detoxification of PCDD/Fs in MSWIFA. The mass and WHO-TEQ degradation efficiencies of PCDD/Fs significantly increased from -92.79% and -51.46%-98.57% and 96.10%, respectively, by the addition of electrolytic manganese residue (EMR) with an MSWIFA/EMR ratio of 3:7 in the thermal treatment of MSWIFA at 250 °C for 60 min. The WHO-TEQ concentration of PCDD/Fs in the treated sample decreased to 3.7 ng WHO-TEQ/kg, meeting the European end-of-waste criteria (20 ng WHO-TEQ/kg). The excellent degradation effect of EMR on PCDD/Fs in MSWIFA could be attributed to two aspects: 1) the manganese oxides in EMR has a catalytic effect on the degradation of PCDD/Fs; 2) the NH₃ generated by the decomposition of (NH₄)₂SO₄ in EMR is conducive to the degradation and resynthesis inhibition of PCDD/Fs. Besides, the thermodynamic calculations indicated that CaClOH in MSWIFA played a crucial role in the decomposition of (NH₄)₂SO₄ in EMR. In addition, the degradation pathways and mechanisms of PCDD/Fs-homologues under the synergistic effect of manganese oxides, ammonia, and thermal field were investigated through comparative analysis of concentration and fingerprint of PCDD/Fs.

Keywords: Comprehensive utilization; Detoxification; Electrolytic manganese residue; Municipal solid waste incineration fly ash; PCDD/Fs.