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[Display omitted] • Lamellar cluster LDH in situ grew on the MIL-88A template. • Dispersed LDH covers stably activate PMS at wide circumneutral pH from 2.5 to 10.5. • Disequilibrium of hydrolysis-precipitation in limit pH caused catalysis declines. • ROSs reconfiguration and dissociable SMT reactivity were examined in limited pH. • Toxicity of structural rearrangements in sulfonamide moiety was revealed. The development of effective and reliable Fenton-like catalytic systems in circumneutral pH is a longstanding interest. Metal-organic framework derivatives become promising catalyst candidates due to high catalytic accessibility and structural flexibility, but their stability remains in doubt. Herein, a MIL-88A self-templating strategy to synthesize structurally decentralized FeCo-layered-double hydroxide (FeCo-LDH, M−FCL) was proposed. The well-constructed M−FCL 3 presented superior peroxymonosulfate (PMS) activation for nearly 100 % sulfamethazine (SMT) degradation within 15 min, which was virtually wobble-slight in the pH = 2.5 ∼ 10.5 range. The performance decrease at limiting pH was mainly ascribed to activity-blocked of M−FCL 3 by analyzing the involved reaction substrates and reactive oxygen species. In specific, the hydrolytic detachment or excessive aggregation of surface-active FeCo-LDH occurred at limiting pH with unbalanced hydrolysis-coprecipitation. Especially, theoretical calculations further exposed that the loss of dominated active Co site and the formation of inert SMT+ dissociating species were detrimental to the catalytic process in acidic environments. Nevertheless, the well-founded resistance of the constructed M−FCL 3 /PMS system to interference and its ability to operate for a long period proved its potential for application in near-neutral environments. This work raised concern for the variations of Fenton-like catalysis at limiting pH, promoting the application of MOF-derived LDH for environmental remediation. [ABSTRACT FROM AUTHOR]

[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]

[Display omitted] • Surface-modified bismuth vanadate is prepared for PMS activation under visible light. • CIP oxidation in BVO-2/PMS/Vis system is dominated by 1O 2 and photogenerated holes. • Surface C O acts as Lewis base site to induce PMS hydrolysis in acidic condition. • The efficiently separated electrons can reduce PMS for SO 4 − and OH generation. Lewis basic sites have been shown to induce singlet oxygen (1O 2) generation in metal-free catalysts while have yet to be elucidated in metal-containing bismuth vanadate (BiVO 4). Herein, surface-modified BiVO 4 photocatalysts are developed and applied in peroxymonosulfate (PMS) activation for ciprofloxacin (CIP) abatement employing 1O 2 and photogenerated holes as the primary reactive species. The surface carbonyl moiety acts as Lewis basic sites to induce PMS hydrolysis under acidic conditions for 1O 2 generation. The occurrence of electron transfer from PMS to catalyst accounts for 1O 2 generation via PMS oxidation. Moreover, PMS as an electron acceptor kinetically accelerates charge separation, not only inducing SO 4 − and OH generation but also allowing direct oxidation of CIP by efficiently separated holes. Accordingly, the optimal BVO-2/PMS/Vis system can completely degrade CIP in 9 min under visible light with a reaction rate of 0.4264 min−1, far exceeding the BVO-2/PMS (0.0063 min−1) and BVO-2/Vis (0.0411 min−1) systems. [ABSTRACT FROM AUTHOR]

We reported the discovery and identification of emerging sulfur-containing polycyclic aromatic hydrocarbons, namely polycyclic aromatic sulfur heterocycles (PASHs), in PM 2.5 collected from two typical regions of China, Taiyuan and Guangzhou. Until now, there is no research on contamination status, sources and potential health risks of this unexpected group of organic contaminants in PM 2.5. High atmospheric concentrations (ng m−3) and significant time-dependent variations were determined in PM 2.5 of Taiyuan from 2017 to 2018. Coal combustion/secondary formation and traffic emission/secondary formation were apportioned as possible pollution sources for the PM 2.5 -bound PASHs in Taiyuan and Guangzhou, respectively. Dithiothreitol and cell viability assays were applied for evaluations of PASH-induced reactive oxygen species (ROS) production and cell toxicity based on the determined real exposure levels for adults. The results illustrated that PASHs in PM 2.5 possibly caused oxidative stress and inhibition of human bronchial epithelial cells in seriously polluted regions such as Taiyuan, suggesting that the pollutant-induced health concerns may need more investigations. This study provides new insights into PM 2.5 pollution, and is beneficial for the development of effective contamination control strategies and reduction of risks on public health. [Display omitted] • Detailed contamination levels of PM 2.5 -bound PASHs were firstly studied. • Different pollution sources were identified in Taiyuan and Guangzhou. • The PM 2.5 -bound PASHs possessed potential health risks for human inhalation. [ABSTRACT FROM AUTHOR]