Promoted generation strategies and corresponding roles of singlet oxygen in activation of persulfate by nanoscale zero-valent iron systems.

[Display omitted] • The promoted generation strategies of 1O 2 in PS activation by modified-nZVI systems and nZVI-based coupling systems are summarized. • The influence factors on the generation and behavior of 1O 2 in nZVI/PS-based systems are reviewed. • The selectivity, wide pH adaptability and corresponding roles of 1O 2 in organic pollutants degradation are reviewed. • The challenges and prospects of 1O 2 generation in nZVI/PS-based systems are addressed. In recent years, the remediation of water contamination through non-radical pathways by singlet oxygen (1O 2) has caught scientists' increasing attention owing to the adaptability to wider pH range and superior selectivity to target pollutants. In this review, strategies of promoting the generation of 1O 2 in persulfate activation over nanoscale zero-valent iron (nZVI) and the corresponding roles of 1O 2 in degrading pollutants are summarized systematically, chiefly illustrating the mechanisms of persulfate activation to produce 1O 2. The reasons underlying improvements in the degradation of organic pollutants originate from increased generation and enhanced activity of 1O 2 in modified systems and coupling systems based on nZVI. Additionally, in order to figure out how external environment affects the generation and behavior of 1O 2 , several major influence factors are also compared and evaluated. On the whole, this paper draws a relatively clear picture of 1O 2 in the combination of persulfate and nZVI-based systems, opening novel perspective of capitalizing on the merits of 1O 2 to deal with the increasingly troublesome problem of water pollution. [ABSTRACT FROM AUTHOR]