Development of phosphorus-based inhibitors for PCDD/Fs suppression. (1st January 2021)

• Record Type: Journal Article
• Authors: Lu, Shengyong; Xiang, Yifan; Chen, Zhiliang; Chen, Tong; Lin, Xiaoqing; Zhang, Weifeng; Li, Xiaodong; Yan, Jianhua
• Is Part Of: Waste management. Volume 119(2021)
• Page Start: 82
• Page End: 90
• Publication Date: 2021-01-01
• Subjects: PCDD/Fs -- Inhibition -- Phosphorus based compounds -- Morphological characterization -- Chemical reaction simulation; Hazardous wastes -- Periodicals; Refuse and refuse disposal -- Periodicals; 363.728
• DOI: 10.1016/j.wasman.2020.09.019
• Languages: English
• ISSNs: 0956-053X

Abstract

Graphical abstract: Highlights: TUA and ADP could inhibit PCDD/Fs by 97.2% and 98.2%, Strengthening C oxidation and inhibiting organic chlorine formation were observed. Catalytic metal could be deactivated into CuS and Cu2 S by S and into Cu2 P2 O7 by P. Converting Cl2 to HCl was the main inhibition mechanisms of N- based inhibitors. Abstract: Inhibition mechanisms of sulfur-, nitrogen- and phosphorus- based inhibitors on the de novo synthesis of polychlorinated dibenzo-p-dioxins, and dibenzofurans (PCDD/F) were studied by exploring speciation evolution of carbon, chorine and copper in fly ash under laboratory-scale experiments. Significant inhibition of PCDD/Fs by thiourea (TUA) and ammonium dihydrogen phosphate (ADP) was observed as 97.2% and 98.2%, respectively, except for potassium dihydrogen phosphate (PDP). ADP and PDP exhibited better inhibition on PCDFs than on PCDDs, whereas TUA exhibited the opposite effect. After adding inhibitors, the proportion of C-O/C=O/O-C=O bonds at the surface of fly ash increased, and stronger oxidation of carbon occurred, together with the conversion from Cu 2+ to Cu + and the inhibition of organic chlorine formation. Kinetic model results indicated that TUA might either suppress the carbon gasification or promote the decomposition of PCDD/Fs, resulting in a remarkable inhibition of PCDD/Fs formation. Simulated chemical reaction equilibrium further comfirmed that catalytic metal could be deactivated into CuS and Cu2 S by sulfur, and into Cu2 P2 O7 by phosphorus. Moreover, NH3, decomposed from TUA and ADP, was able to convert Cl2 into HCl, albeit with a weaker chlorination ability. This study of inhibition mechanisms is useful for the exploration and utilization of efficient inhibitors in full-scale incinerators.