Insight into the role of heterogeneous Fenton-like catalyst FeCo-γ-Al2O3 with dual electron-rich centers for Ni-EDTA removal.

To enhance the polarization distribution of electron cloud density on the catalyst surface, we have introduced a novel bimetallic-substituted dual-reaction center (DRC) catalyst (FeCo-γ-Al2O3) comprising iron (Fe) and cobalt (Co) for the decomplexation and mineralization of heavy metal complex Ni-EDTA in this study. Compared to the catalysts doped solely with Fe or Co, the bimetal-doped catalyst offered several advantages, including enhanced electron cloud polarization distribution, additional electron transfer pathway, and improved capacity of free radical generation. Through DFT calculations and EPR tests, we have elucidated the influences of the catalyst's adsorption toward Ni-EDTA and its decomplexation products on the electron transfer between the pollutant and the catalyst. The competition between the pollutants and H2O2 affects the generation of free radicals in both electron-rich Fe and Co centers as well as electron-deficient Al center. Building on these findings, we have proposed a plausible removal mechanism of Ni-EDTA using the heterogeneous Fenton-like catalyst FeCo-γ-Al2O3. This study sheds light on the potential of FeCo-γ-Al2O3 as a DRC catalyst and emphasizes the significance of pollutant characteristics in determining the catalyst's performance.

[Pollution Characteristics and Source Apportionment of Atmospheric Volatile Organic Compounds in Winter in Kaifeng City].

In order to explore the pollution characteristics and sources of atmospheric volatile organic compounds (VOCs) in winter in Kaifeng City, based on the atmospheric VOCs component data obtained from the online monitoring station of the Kaifeng Ecological and Environmental Bureau (Urban Area) from December 2021 to January 2022, the pollution characteristics of VOCs and secondary organic aerosol formation potential (SOAP) were discussed, and the sources of VOCs were analyzed by using the PMF model. The results showed that the average mass concentration of VOCs in winter in Kaifeng City was (104.71±48.56) µg·m-3, and alkanes (37.7%) had the highest proportion of mass concentrations, followed by that of halohydrocarbons (23.5%), aromatics (16.8%), OVOCs (12.6%), alkenes (6.9%), and alkynes (2.6%). The averaged total SOAP contributed by VOCs was 3.18 µg·m-3, of which aromatics contributed as much as 83.8%, followed by alkanes (11.5%). The largest anthropogenic source of VOCs in winter in Kaifeng City was solvent utilization (17.9%), followed by fuel combustion (15.9%), industrial halohydrocarbon emission (15.8%), motor vehicle emission (14.7%), organic chemical industry (14.5%), and LPG emission (13.3%); solvent utilization contributed 32.2% of the total SOAP, followed by motor vehicle emission (22.8%) and industrial halohydrocarbon emission (18.9%). It was found that reducing VOCs emissions from solvent utilization, motor vehicle emission, and industrial halohydrocarbon emission was important to control the formation of secondary organic aerosols in winter in Kaifeng City.

Toxicity and endocrine-disrupting potential of PM2.5: Association with particulate polycyclic aromatic hydrocarbons, phthalate esters, and heavy metals.

The adverse effects of fine atmospheric particulate matter with aerodynamic diameters of ≤2.5 µm (PM2.5) are closely associated with particulate chemicals. In this study, PM2.5 samples were collected from highway and industry sites in Hangzhou, China, during the autumn and winter, and their cytotoxicity and pulmonary toxicity and endocrine-disrupting potential (EDP) were evaluated in vitro and in vivo; the particulate polycyclic aromatic hydrocarbons (PAHs), phthalate esters (PAEs), and heavy metals were then characterized. The toxicological results suggested that the PM2.5 from highway site induced higher cytotoxicity (cell viability inhibition, intracellular oxidative stress, and cell membrane injury) and pulmonary toxicity (inflammatory response (IR) and oxidative stress (OS)) than the samples from industry site, while the PM2.5 from industry site exhibited higher EDP (estrogenic and anti-androgenic activity). The cytotoxicity and pulmonary toxicity of PM2.5 in the winter were higher than those in the autumn, while no seasonal difference in the endocrine-disrupting potential was observed (p > 0.05). The Pearson correlation analysis between the biological effects and particulate chemicals revealed that the PM2.5-induced inflammatory response and oxidative stress were closely associated with the particulate PAHs and heavy metals (Pearson correlation coefficients: rIR, PAHs = 0.822-0.988, rIR, heavy metals = 0.895-0.971, rOS, PAHs = 0.843-0.986, and rOS, heavy metals = 0.887-0.933), while particulate di (2-ethylhexyl)phthalate (DEHP) substantially contributed to the EDP of PM2.5 (rEDP, DEHP = 0.981). This study indicated that the toxicity and EDP of PM2.5 could vary with the surrounding environment and season, which was closely associated with the variations of particulate chemicals. Further studies are needed to clarify the associations between the harmful effects of PM2.5 and other contributing factors.

Preparation of Ce0.9Zr0.1O2/SnIn4S8 composite photocatalyst and its degradation of typical antibiotic pollutants.

Considering the high environmental risk, the remediation of antibiotic pollutants attracted numerous attentions. In this work, a novel photocatalyst, Ce0.9Zr0.1O2/SnIn4S8, was fabricated by in situ precipitation and hydrothermal method and then applied to the degradation of norfloxacin under the irritation of visible light. The SEM, TEM, XRD, XPS, and electrochemical results clearly showed that the n-type heterojunction between Ce0.9Zr0.1O2 and SnIn4S8 was successfully constructed, which greatly reduces the recombination of the photogenic electron and holes, leading to the improvement of photocatalytic performance and stability (recycled over eight times). Besides, the Ce0.9Zr0.1O2/SnIn4S8 composite also exhibited good ability to mineralize norfloxacin. Under the optimal condition (pH 3, 1 g L-1 of 10% Ce0.9Zr0.1O2/SnIn4S8, and 8 mg L-1 of initial norfloxacin concentration), norfloxacin could be fully and rapidly degraded in 60 min, and completely mineralized in 4 h (99.3 ± 1.7%). LC-QTOF-MS results evidently displayed eight intermediates during norfloxacin degradation. In addition, with the attack of the reactive oxygen species (h+, •OH, and •O2-), norfloxacin could be effectively decomposed via deoxygenation, hydroxylation, and carboxylation reactions. Notably, compared to photodegradation, the photocatalytic process could completely eliminate the norfloxacin from water because it could avoid the accumulation of toxic byproducts.

Rapidly photocatalytic mineralization of typical veterinary drugs with the SnO2/SnIn4S8 composite.

Considering the high environmental risk, the remediation of veterinary drug pollutants aroused numerous concerning. In this paper, a novel photocatlyst, SnO2/SnIn4S8, was fabricated by in situ precipitation and hydrothermal method and then employed to simulate photocatalytic degradation of olaquindox under visible light. The SEM, TEM, XRD, XPS and electrochemical results clearly showed that the n-type heterojunction between SnO2 and SnIn4S8 was successfully constructed, which greatly reduce the recombination of the photogenic electron and holes, leading to the improvement of photocalytic performance and stability (recycled over 10 times). Besides, the SnO2/SnIn4S8 composite also exhibited good ability to mineralize the olaquindox. Under the optimal condition (pH of 3, 1 g L-1 of 30 wt% SnO2/SnIn4S8 and 10 mg L-1 of initial olaquindox concentration), the olaquindox could be fully and rapidly degraded in 25 min, and completely mineralized in 2 h (99.3 ± 1.7%). LC-QTOF-MS analysis evidently displayed 10 intermediates during the olaquindox degradation. In addition, with the attack of the reactive oxygen species (h+, •OH and •O2-), olaquindox could be effectively decomposed via deoxygenation, hydroxylation and carboxylation reactions. Importantly, compared to photodegradation, the photocatalytic process was an ideal way to eliminate the olaquindox form water because it could avoid the accumulation of toxic byproducts.

Constructing a novel family of halogen-doped covalent triazine-based frameworks as efficient metal-free photocatalysts for hydrogen production.

Halogens, as typical non-metal dopants, have attracted intensive interests for developing highly active photocatalysts. However, the essential factors and underlying mechanism of halogen modification are still unclear. Herein, we systematically report the development of halogen (F, Cl and Br)-doped covalent triazine-based frameworks (CTFs) via a facile thermal treatment of CTFs and an excess of ammonium halide. The introduction of halogen atoms endowed CTFs with multiple superior effects such as improved optical absorption, promoted charge migration, narrowed band gaps and tuned band positions. The newly developed halogen-doped CTFs showed remarkable photocatalytic activities for H2 evolution under visible-light irradiation. Notably, the most enhanced photocatalytic performance was obtained with Cl-doped CTFs, which exhibited 7.1- and 2.4-fold enhancements compared to un-doped CTFs and Cl-doped g-C3N4, respectively. The electronegativity and atomic radius of the halogen atoms affected the modification of the optical and electronic properties, leading to different photocatalytic performances of F-, Cl- and Br-doped CTFs. The conclusions presented in this work will provide some new insights into the understanding of the doping effect for the improvement of the photocatalytic activity of halogen-doped CTF photocatalysts.