Leaching behavior of Sb and Br from E-waste flame retardant plastics.

Zhan L, Zhao X, Ahmad Z, Xu Z

Chemosphere

Apr 1, 2020

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Abstract

The improper disposal of E-waste flame retardant plastics laden with antimony (Sb) and bromine (Br) has brought enormous environmental hazards, however, rare information on the effective removal of Sb and Br is available. In this study, through building an alkaline sulfide system under hydrothermal conditions, Sb and Br were simultaneously extracted from flame retardant plastic with high efficiency of 85.60% and 90.13%, respectively. Sulfur ion through mass transfer reacted with encapsulated SbO to form safe and non-toxic SbS. Alkaline solution trapped the Br through substitution or neutralization reaction to inhibit the formation of brominated organic compounds. The results showed that the optimum temperature, residence time, NaS and NaOH concentration for hydrothermal removal of Sb and Br were 220 °C, 2 h, 50 g/L and 20 g/L. The results also revealed that both NaS and NaOH played an interrelated role in the process of Sb removal. However, NaOH was the only factor controlling the process of debromination. Moreover, the FTIR structure of plastic after alkaline sulfide hydrothermal treatment remained unchanged, which implies that the treated plastic can be reused, and is an added advantage of this technology. The TG-DTG analysis proved the effectiveness of alkaline sulfide hydrothermal treatment in removing Sb and Br.

Affiliation

School of Environmental Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, China; Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration, School of Ecological and Environmental Science, East China Normal University, 500 Dongchuan Road, Shanghai, 200241, China; Shanghai Institute of Pollution Control and Ecological Security, 1515 North Zhongshan Road, Shanghai, 200092, China. Electronic address: [email protected].