The impact of background constituents on the degradation of trace levels of micropollutants by two advanced oxidation processes: UV/H₂O₂ and UV/TiO₂ was studied. Experimental results demonstrated that the background scavenging rate rather than the concentration of micropollutant controls the required UV irradiation dose. The character of the natural organic matter had a limited impact on scavenging when the water source remains unchanged, however, a periodic bleed of hydrophobic material may substantially increase the minimum UV dose required to reach the desired micropollutant concentration. Moreover, in the case of UV/TiO₂, high concentrations of background organic matter do not only act as scavengers but also saturate the TiO₂ surface. Alkalinity inhibits the efficacy of UV/TiO₂ photocatalysis due to the formation of large TiO₂ aggregates. The study also demonstrated that the use of synthetic waters for treatability test purposes was an acceptable approach as long as both the background organic matter and the alkalinity were matched to that of the projected application. Finally spiking micropollutants at higher concentrations does not alter the significance of the findings as long as the background constituents represent more than 85% of the total scavenging rate.
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http://dx.doi.org/10.1016/j.watres.2013.01.022 | DOI Listing |
Environ Sci Technol
January 2025
State Key Laboratory of Black Soils Conservation and Utilization, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Shengbei Street 4888, Changchun 130102, China.
Climate change and human activity are increasing the frequency of wildfires in peatlands and threatening permafrost peatland carbon pools. In Northeast China, low-severity prescribed fires are conducted annually on permafrost peatlands to reduce the risk of wildfires. These fires typically do not burn surface peat but lead to the loss of surface vegetation and introduction of pyrogenic carbon.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Center for Electron Microscopy, South China University of Technology, Guangzhou 511436, China.
Adsorption behaviors are typically examined through adsorption isotherms, which measure the average adsorption amount as a function of partial pressure or time. However, this method is incapable of identifying inhomogeneities across the adsorbent, which may occur in the presence of strong intermolecular interactions of the adsorbate. In this study, we visualize the adsorption of molecular iodine (I) in the metal-organic framework material MFM-300(Sc) using high-resolution scanning transmission electron microscopy (STEM).
View Article and Find Full Text PDFSmall
January 2025
School of Chemical Engineering and Technology, Xi'an Jiaotong University, Xi'an, 710049, China.
The photocatalytic conversion of CO into products such as CH and CH poses a significant challenge due to the lengthy reaction steps and the high energy barrier involved. In this study, both benzothiadiazole (BTD) and hydroxyl groups (-OH) are introduced into cobalt-based polymerized porphyrinic network (PPN) through a C-C coupling reaction. This modification of orbital energy levels that strengthens the ability of gain electrons and facilitates the charge transfer in PPN.
View Article and Find Full Text PDFToxics
January 2025
School of Computer Science and Hubei Key Laboratory of Intelligent Geo-Information Processing, China University of Geosciences, Wuhan 430078, China.
Anaerobic digestion (AD) technology offers significant advantages in addressing environmental issues arising from the intensification of livestock production since it enables waste reduction and energy recovery. However, the molecular composition of dissolved organic matter (DOM) and its linkages to microbial biodiversity during the industrial-scale AD process of chicken manure (CM) remains unclear. In this study, the chemical structure of CM digestate-derived DOM was characterized by using multi-spectroscopic techniques and ultrahigh-resolution mass spectrometry, and the microbial composition was detected by using 16S rRNA gene sequencing.
View Article and Find Full Text PDFToxics
December 2024
State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
Ecological integrity, encompassing physical, chemical, and biological aspects, is crucial for sustaining ecosystem service functions and stability. As the largest freshwater lake in China, the ecological integrity of Poyang Lake has attracted much attention due to the over-exploitation of its water resources in recent years. In this study, several biological and water quality surveys on water ecological conditions were carried out at 11 sampling points of Poyang Lake from 1998 to 2022, and the ecological health of Poyang Lake was evaluated by use of the O/E (Observation/Expectation) model and the chemical-biological index method according to the status of the water quality and the structure of the benthic fauna in the four seasons, respectively.
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