Although Fenton or Fenton‐like reactions have been widely used in the environment, biology, life science, and other fields, the sharp decrease in their activity under macroneutral conditions is still ...a large problem. This study reports a MoS2 cocatalytic heterogeneous Fenton (CoFe2O4/MoS2) system capable of sustainably degrading organic pollutants, such as phenol, in a macroneutral buffer solution. An acidic microenvironment in the slipping plane of CoFe2O4 is successfully constructed by chemically bonding with MoS2. This microenvironment is not affected by the surrounding pH, which ensures the stable circulation of Fe3+/Fe2+ on the surface of CoFe2O4/MoS2 under neutral or even alkaline conditions. Additionally, CoFe2O4/MoS2 always exposes “fresh” active sites for the decomposition of H2O2 and the generation of 1O2, effectively inhibiting the production of iron sludge and enhancing the remediation of organic pollutants, even in actual wastewater. This work not only experimentally verifies the existence of an acidic microenvironment on the surface of heterogeneous catalysts for the first time, but also eliminates the pH limitation of the Fenton reaction for pollutant remediation, thereby expanding the applicability of Fenton technology.
We have successfully constructed an acidic microenvironment on the surface of CoFe2O4 by chemical bonding MoS2, which ensures the stable circulation of iron ions in the slipping plane and truly overcomes the limitation of pH in pollutant control, thereby expanding the applicability of Fenton technology.
Abstract
Gut microbiota have attracted extensive attention recently because of their important role in host metabolism, immunity and health maintenance. The present study focused on factors affecting ...the gut microbiome of grass carp (Ctenopharyngodon idella) and further explored the potential effect of the gut microbiome on metabolism. Totally, 43.39 Gb of screened metagenomic sequences obtained from 24 gut samples were fully analysed. We detected 1228 phylotypes (116 Archaea and 1112 Bacteria), most of which belonged to the phyla Firmicutes,Proteobacteria and Fusobacteria. Totally, 41 335 of the detected open reading frames (ORFs) were matched to Kyoto Encyclopedia of Genes and Genomes pathways, and carbohydrate and amino acid metabolism was the main matched pathway deduced from the annotated ORFs. Redundancy analysis based on the phylogenetic composition and gene composition of the gut microbiome indicated that gut fullness and feeding (i.e. ryegrass vs. commercial feed, and pond-cultured vs. wild) were significantly related to the gut microbiome. Moreover, many biosynthesis and metabolism pathways of carbohydrates, amino acids and lipids were significantly enhanced by the gut microbiome in ryegrass-fed grass carp. These findings suggest that the metabolic role played by the gut microbiome in grass carp can be affected by feeding. These findings contribute to the field of fish gut microbial ecology and also provide a basis for follow-up functional studies.
The present study focused on factors affecting the gut microbiome of grass carp and further explored the potential effect of the gut microbiome on metabolism.
In this article, an effective schematic is developed for estimating sea ice thickness (SIT) from the reflectivity (Γ) produced with TechDemoSat-1 (TDS-1) Global Navigation Satellite ...System-Reflectometry data. Here, Γ is formulated as the product of the propagation loss due to SIT and the reflection coefficient of underlying seawater. The effect of surface roughness on Γ is neglected when only considering signals of coherent reflection. In practice, Γ at the specular point is first generated using TDS-1 data. Afterwards, SIT is calculated from TDS-1 Γ based on the proposed reflectivity model, and verified with two sets of reference SIT data; one is obtained by the Soil Moisture Ocean Salinity (SMOS) satellite, and the other is the combined SMOS/Soil Moisture Active Passive (SMAP) measurements. This analysis is performed on the data with SIT less than 1m. Through comparison, good consistency between the derived TDS-1 SIT and the reference SIT is obtained, with a correlation coefficient (r) of 0.84 and a root-mean-square difference (RMSD) of 9.39 cm with SMOS, and an r of 0.67 and an RMSD of 9.49 cm with SMOS/SMAP, which demonstrates the applicability of the developed model and the utility of TDS-1 data for SIT estimation. In addition, this method is proved to be useful for improving existing sea ice detection accuracy.
Knowledge of sea ice is critical for offshore oil and gas exploration, global shipping industries, and climate change studies. During recent decades, Global Navigation Satellite System-Reflectometry ...(GNSS-R) has evolved as an efficient tool for sea ice remote sensing. In particular, thanks to the availability of the TechDemoSat-1 (TDS-1) data over high-latitude regions, remote sensing of sea ice based on spaceborne GNSS-R has been rapidly growing. The goal of this paper is to provide a review of the state-of-the-art methods for sea ice remote sensing offered by the GNSS-R technique. In this review, the fundamentals of these applications are described, and their performances are evaluated. Specifically, recent progress in sea ice sensing using TDS-1 data is highlighted including sea ice detection, sea ice concentration estimation, sea ice type classification, sea ice thickness retrieval, and sea ice altimetry. In addition, studies of sea ice sensing using airborne and ground-based data are also noted. Lastly, applications based on various platforms along with remaining challenges are summarized and possible future trends are explored. In this review, concepts, research methods, and experimental techniques of GNSS-R-based sea ice sensing are delivered, and this can benefit the scientific community by providing insights into this topic to further advance this field or transfer the relevant knowledge and practice to other studies.
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•Microbial networks were distinctly different among seasons.•Networks with higher complexity and more keystone taxa exhibited higher stability.•Water temperature and pH influenced ...microbial networks and community stability.•Keystone taxa could be regarded as the indicators of community stability.
Seasonal variations of environmental factors generally result in considerable changes in microbiomes, yet we still lack a clear understanding of how microbial communities maintain their ecological stability. Here, we analyze a long-term (nine years) high-throughput sequencing dataset by network analysis to illustrate how the microbial stability varies among seasons in lake ecosystems. The results showed that the microbial networks were distinctly different among seasons, and the most complex network in autumn exhibited the highest stability. We found that the strong connecting structures among microbes (large modules) were significantly (P < 0.05) correlated with water temperature and pH, which would negatively affect keystone taxa and destabilize microbial communities. The networks with more keystone taxa were generally stable and the removal of keystone taxa would result in unstable networks. Moreover, the keystone taxa were specific among seasons due to environmental filtering and relevant interspecific interactions. These results suggested that seasonal variations of environmental factors could influence microbial networks and community stability via the regulation of keystone taxa. Thus, the keystone taxa could be used as indicators to reflect the seasonal stability of microbial communities in lake ecosystems. These findings improve our understanding of the microbial seasonal co-occurrence patterns and reveal the mechanism how microbial communities maintain their seasonal stability in aquatic ecosystems.
Algal bloom has become a serious environmental problem caused by the overgrowth of plankton in many waterbodies, and effective remote sensing methods for monitoring it are urgently needed. Global ...navigation satellite system-reflectometry (GNSS-R) has been developed rapidly in recent years, which offers a new perspective on algal bloom detection. When algal bloom emerges, the water surface will turn smoother, which can be detected by GNSS-R. In addition, meteorological parameters, such as temperature, wind speed and solar radiation, are generally regarded as the key factors in the formation of algal bloom. In this article, a new algal bloom detection method aided by machine learning and auxiliary meteorological data is established. This work employs the Cyclone GNSS (CYGNSS) data and the fifth generation European Reanalysis (ERA-5) data with the application of the random under sampling boost (RUSBoost) algorithm. Experiments were carried out for Taihu Lake, China, over the period of August 2018 to May 2022. During the evaluation stage, the test true positive rate (TPR) of 81.9%, true negative rate (TNR) of 82.9%, overall accuracy (OA) of 82.9% and the area under (receiver operating characteristic) curve (AUC) of 0.88 were achieved, with all the GNSS-R observables and meteorological factors being involved. Meanwhile, the contribution of each meteorological factor and the error sources were assessed, and the results indicate that temperature and solar radiation play a prominent role among other meteorological factors in this research. This work demonstrates the capability of CYGNSS as an effective tool for algal bloom detection and the inclusion of meteorological data for further enhanced performance.
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•Rainy-season rainfall erosivity in China has decadal change around 2003 and 2008.•Pacific Decadal Oscillation modulated rainy-season rainfall erosivity in the Yangtze River basin and ...the source of three rivers.•Atlantic and Indian Ocean warming affected rainy-season rainfall erosivity in northeastern and north China.•The effect of sea surface temperature on rainy-season rainfall erosivity in sub-regions was shown as different resonant periods.
Rainfall erosivity is a crucial indicator of soil erosion that affects sediment management and agricultural security. Understanding the decadal change of rainfall erosivity during rainy season (RERS), when soil erosion occurs most frequently, is critical for environmental management and agricultural planning under climate change. However, whether RERS in mainland China has experienced decadal change and how it responds to large-scale climate indicators is unclear. Here, the decadal changes of RERS over mainland China and its underlying causes according to climate factors are investigated. The multi-scale moving t-test was used to determine the rainy season, and the rotated empirical orthogonal function analysis was applied to divide mainland China into sub-regions. Three abruption-detection methods were used to determine the decadal variation of RERS. Results show that: (1) RERS in China experienced different decadal change characteristics in different sub-regions. In the Yangtze River basin and the source of three rivers, the decadal change of RERS occurred around 2003, while RERS showed a prominent increasing trend over northeastern and northern China after 2008. (2) Significant negative (positive) trend of RERS over the Yangtze River basin (the source of three rivers) after 2003 was related to enhanced monsoon and anomalous divergence (convergence) modulated by Pacific Decadal Oscillation (PDO). By contrast, the prominent increasing trend after 2008 over northeastern and northern China was correlated to the Northern China Cold Vortex and Atlantic and Indian Ocean warming. (3) The non-stationary characteristic between sea surface temperature (SST) and RERS was reflected by the cross-wavelet transform. The influence of PDO over the Yangtze River basin and the source of three rivers was shown as long-term (8–13 years) or short-term (2–6 years) resonant periods. In contrast, the effect of SST over the Indian Ocean and the Atlantic Ocean is mainly presented as short-term resonant periods. These results suggest that the decadal change of RERS is closely related to the changes in SST and particular atmospheric circulation, and understanding these oceanic and atmospheric dynamics is helpful for agricultural security and environmental management under RERS changes.
In the field of environmental science, the ideal Fenton reaction is, by definition, Fe2+-catalyzed production of hydroxyl radicals from H2O2. However, in reality, most of the reported Fenton ...reactions are not real catalytic reactions but redox processes, since when Fe2+ activates H2O2, it becomes Fe3+, and the return to Fe2+ can be difficult. The introduction of a cocatalyst can solve this problem. Here, we review the recent development of typical cocatalytic Fenton strategies for pollutant control, including cocatalysts based on organic acids, zero-valent metals, single atoms, and metal sulfides. The catalytic mechanisms are summarized and cocatalyst regenerations and advantages are examined. It is hoped that our review will enable chemists to develop new catalysts and cocatalysts while focusing on how to use the simplest chemical methods to make the Fenton system work in a stable manner in the long run.
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Adding cocatalysts can effectively promote the efficiency of the Fenton reaction. Yan et al. summarize recent research on typical cocatalytic Fenton strategies for pollutant control, as well as analyzing the mechanisms, cocatalyst regeneration and advantages. They advocate for researchers to serve theory in practice, and promote the long-term stable operation of the industrial Fenton system.
Climate warming is increasingly leading to marked changes in plant and animal biodiversity, but it remains unclear how temperatures affect microbial biodiversity, particularly in terrestrial soils. ...Here we show that, in accordance with metabolic theory of ecology, taxonomic and phylogenetic diversity of soil bacteria, fungi and nitrogen fixers are all better predicted by variation in environmental temperature than pH. However, the rates of diversity turnover across the global temperature gradients are substantially lower than those recorded for trees and animals, suggesting that the diversity of plant, animal and soil microbial communities show differential responses to climate change. To the best of our knowledge, this is the first study demonstrating that the diversity of different microbial groups has significantly lower rates of turnover across temperature gradients than other major taxa, which has important implications for assessing the effects of human-caused changes in climate, land use and other factors.
•This review assessed the contamination levels of PAE in various ecosystems.•Overviewed the current status of PAE-degrading bacterial isolates and communities.•Discussed the challenges for ...understanding in situ PAE biodegradation mechanisms.•Proposed a guide of building synthetic community to decipher interaction mechanism.
The extensive use of phthalic acid esters (PAEs) has led to their widespread distribution across various environments. As PAEs pose significant threats to human health, it is urgent to develop efficient strategies to eliminate them from environments. Bacteria-driven PAE biodegradation has been considered as an inexpensive yet effective strategy to restore the contaminated environments. Despite great advances in bacterial culturing and sequencing, the inherent complexity of indigenous microbial community hinders us to mechanistically understand in situ PAE biodegradation and efficiently harness the degrading power of bacteria. The synthetic microbial ecology provides us a simple and controllable model system to address this problem. In this review, we focus on the current progress of PAE biodegradation mediated by bacterial isolates and indigenous bacterial communities, and discuss the prospective of synthetic PAE-degrading bacterial communities in PAE biodegradation research. It is anticipated that the theories and approaches of synthetic microbial ecology will revolutionize the study of bacteria-driven PAE biodegradation and provide novel insights for developing effective bioremediation solutions.
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