101. 题目: Reactivity of Bromine Radical with Dissolved Organic Matter Moieties and Monochloramine: Effect on Bromate Formation during Ozonation
102. 题目: Marine nitrogen fixation as a possible source of atmospheric water-soluble organic nitrogen aerosols in the subtropical North Pacific
103. 题目: Heat-induced changes in soil water-extractable organic matter characterized using fluorescence and FTIR spectroscopies coupled with dimensionality reduction methods
Water extractable organic matter (WEOM) is a very mobile and reactive soil OM fraction, critical in the translocation of carbon (C) from soils to other environmental compartments. Transformations of WEOM due to soil heating can have implications not only at a local scale, but in places far away from the location of the event. However, their accurate characterization is costly when analyzing a large number of samples. The objectives of this work were to identify common patterns for the changes in WEOM caused by the heating of various soil types using a combination of spectroscopic and dimensionality reduction techniques. Six soils from Spain, Kenya and Israel were collected at depths 0–10 cm and analysed before and after heating in air to temperatures of 300 and 600 °C. Fluorescence EEMs were measured in soil–water extracts containing WEOM, and decomposed using parallel factor (PARAFAC) analysis. The FTIR spectra were measured in freeze-dried extracts and further analysed using non-negative matrix factorization (NMF). Total organic C and SUVA254 values of the extracts experienced changes with the heating treatments that were soil dependant. Four PARAFAC and three NMF components were sufficient to characterize WEOM changes in all soils, which showed common thermal transformation patterns irrespective of their origin and properties. Thermal transformation of fluorescent WEOM led to the increase in the proportion of a component with an emission maximum at Ex 300/Em 392 nm, and to a lower extent one with the emission maximum at Ex 300/Em 426 nm. Concomitantly, the proportion of components with emission maxima at longer excitation wavelengths was reduced. These changes occurred at the lowest heating temperature and were maintained at 600 °C, and they seem to indicate a depletion of fluorescent components more conjugated, bigger in size, and an enrichment in smaller ones. The NMF components obtained from FTIR spectra showed an increase of the proportion of compounds with CO bonds, more oxidized. No correlations were found between the components obtained with each method, thus indicating that the information obtained from the fluorescence EEMs-PARAFAC analysis and the NMF decomposition of FTIR spectra is complementary. It can be concluded that there is a common pattern of WEOM changes induced by thermal soil transformations irrespective of the origin and properties of the soils studied, and that the combination of different spectroscopic techniques coupled with dimensionality reduction methods can be used as a simple and low-cost method to fingerprint changes in WEOM composition, in general, and those caused by soil heating, in particular.
104. 题目: Priming effect depending on land use and soil types in a typical semi-arid landscape in Kenya
105. 题目: Arsenic adsorption by carboxylate and amino modified polystyrene micro- and nanoplastics: kinetics and mechanisms
We investigated adsorption characteristics of As(III) and As(V) onto two different functionalized polystyrene (PS) microplastics (MPs). Our results show that there is the potential for PS MPs to adsorb both As(III) and As(V). Using a particle size of 80–82 nm, maximum As(III) and As(V) adsorption capacities of 0.57 mg/g and 0.37 mg/g were obtained by PS-COOH MPs. These capacities were markedly higher than those for PS-NH2 MPs, which were 0.41 mg/g and 0.27 mg/g, respectively. The pseudo-second-order adsorption kinetic model was found to effectively describe the sorption kinetics of As(III)/As(V) on two different functionalized PS MPs. Langmuir isotherms better represented the equilibrium adsorption results. The kinetic models, XPS, and FTIR results indicate that hydrogen bonding, hydroxyl complexation, and outer-sphere surface complexation may have partly contributed to adsorption of As onto PS MPs. Adsorption capacity markedly decreases with increasing salinity or presence of humic acids (HA), suggesting an inhibiting effect of salinity and HA through outer-sphere complexation. These findings confirm that microplastics have great potential to adsorb As and hence are ultimately highly likely to affect the environmental behavior of As in an ecosystem.
106. 题目: Formation of necromass-derived soil organic carbon determined by microbial death pathways
Soil organic matter is the dominant carbon pool in terrestrial ecosystems, and its management is of increasing policy relevance. Soil microbes are the main drivers of soil organic carbon sequestration, especially through accumulation of their necromass. However, since the direct characterization of microbial necromass in soil is challenging, its composition and formation remain unresolved. Here we provide evidence that microbial death pathways (the distinct processes of microbial dying) in soil affect necromass composition and its subsequent fate. Importantly, the composition of derived microbial necromass does not equal that of microbial biomass. From biomass to necromass, distinct chemical transformations lead to increases in cell wall/cytoplasm ratios while nutrient contents and easily degradable compounds are depleted. The exact changes depend on environmental conditions and the relevance of different microbial death pathways, for example, predation, starvation or anthropogenic stresses. This has far-reaching consequences for mechanisms underpinning biogeochemical processes: (1) the quantity and persistence of microbial necromass is governed by microbial death pathways, not only the initial biomass composition; (2) efficient recycling of nutrients within microbial biomass presents a possible pathway of organic carbon sequestration that minimizes nitrogen losses; (3) human-induced disturbances affect the causes of microbial death and consequently necromass composition. Thus, new research focusing on microbial death pathways holds great potential to improve management strategies for soil organic carbon storage. Not only microbial growth but also death drive the soil microbial carbon pump.
107. 题目: Effect of tree species and substrate properties on organic phosphorus forms in afforested technosols
108. 题目: Hierarchical porous biochar from kelp: Insight into self-template effect and highly efficient removal of methylene blue from water
Biochar is known to efficiently remove dyes especially for biochar with hierarchical pores and partial N-species. Here, a facile pyrolysis is used to yield N-doped biochar from kelp without additives, showing surface areas of 771 m2/g as temperature up to 1000 °C and hierarchical small-sized mesopores (2–4 nm) and wide meso-macropores (8–60 nm). A possible self-template mechanism from inorganics is proposed to form hierarchical pore architecture in biochar and used for methylene blue (MB) removal. Biochar pyrolyzed at 1000 °C is found to be efficient for MB removal with uptake of 379.8 mg/g under ambient conditions, one of the largest ever recorded uptakes for other biochar without activation, owing to synergistic effects of high surface areas, mesopores, and graphitized N-species. These results confirm that a facile pyrolysis for transformation of kelp into efficient dyes adsorbent is a cost-effective process for economic and environmental protection.
109. 题目: Impact of biochar amendment on antibiotic removal and resistant genes accumulation in microscale constructed wetlands for low C/N artificial wastewater treatment: Performance and mechanism
Constructed wetlands (CWs) amended with biochar to stimulate antibiotic and antibiotic resistance genes (ARGs) removal from low C/N ratio restricts wastewater holds particular application prospect due to high efficiency and good stability. In this study, we conducted biochar amended constructed wetland (BCW) and non-biochar amended constructed wetland (NCW) to explore the feasibility and mechanisms for sulfamethoxazole (SMX) and ARGs removal from low C/N wastewater. Results showed that biochar-amended considerably stimulated the biological oxidation and reduction process in CW, as evidenced by higher chemical oxygen demand (COD), nitrogen, and SMX removal performance (7.1 ± 2.6%, 19.8 ± 3.6%, 36.8 ± 6.2%) than that in NCW. The accumulation of ARGs was negatively associated with SMX removal efficiency, where the int and sul genes performed lower concentration in BCW due to the higher SMX removal efficiency. The biochar’s dissolved organic carbon release in CWs indicated that water and alkaline media portray the optimum conditions for SMX and ARGs removal. Microbial community analysis exposed that more functional consortia capable of SMX metabolism (e.g., Arthrobacter, Ramlibacter, Flavobacterium, and norank_f_JG30-KF-CM45) were enriched in BCW. This study demonstrated the feasibility and mechanism of biochar-amended CWs for regulated SMX removal and ARGs accumulation, which provides new insights for enhancing the depuration ability of CWs.
110. 题目: Manganese effects on plant residue decomposition and carbon distribution in soil fractions depend on soil nitrogen availability
Recent studies have highlighted the critical role of manganese (Mn) in plant litter decomposition and soil organic carbon (C) cycling in forest ecosystems. Long term nitrogen (N) deposition and N fertilization can increase soil acidity and mobilize bioavailable Mn (Mn2+) in soil. However, no studies have examined the interactive effect of N and Mn fertilization on litter decomposition and carbon distribution in agricultural soils, despite agroecosystems being subject to both N and Mn management. We hypothesized that increased soil N and Mn availability would accelerate plant residue decomposition and transfer of its C to mineral-associated organic matter (MAOM), and that the combined effect of Mn and N enrichment would be greater than the individual effect. We conducted a laboratory incubation experiment by adding 13C-labeled residue of perennial grass Glyceria striata (Lam.) to agricultural soils that had received 225 kg N ha−1 yr−1 for 27 years (N1) and comparable soils that received no N (N0). Before the experiment, these soils also received three levels of dissolved Mn2+, designated M0 (no additional Mn), M1 (50 mg kg−1), or M2 (250 mg kg−1). We measured total CO2 production as well as distribution of 13C from the residue into CO2, particulate organic matter (POM), MAOM, and dissolved organic carbon (DOC) over a 1-year period. Manganese amendments significantly increased CO2 production from residue decomposition in the N1 soil, but no such effect was observed in the N0 soil. Manganese also accelerated the loss of residue-derived C from POM and DOC, but increased its recovery in MAOM. However, the positive effect of added Mn in decomposition and recovery in MAOM in the presence of N fertilization occurred only during the initial 30-day decomposition period, where M2 showed a 12% increase in cumulative CO2 production from residue, 8% increase in POM loss, and 43% increase in recovery of residue C in MAOM compared to M0. For M1, only CO2 emission from residue was significantly higher than Mo during this period. At 365 days M2 showed 8% increase in CO2 production, 1% increase in POM loss, and 16% increase in recovery of residue C in MAOM compared to M0, but none of these were statistically significant (p < 0.05). This study adds to the growing evidence that increasing Mn availability enhances plant litter decomposition. However, the occurrence and magnitude of Mn-induced stimulation of decomposition is context specific. Further investigation with greater temporal resolution, involving a multitude of litter and soil types and including microbial compositional and functional characterization, is recommended to fully elucidate the interactive role of Mn and N on C cycling.
111. 题目: Humic Substance Photosensitized Degradation of Phthalate Esters Characterized by 2H and 13C Isotope Fractionation
112. 题目: Synergistic use of biochar and the plant growth-promoting rhizobacteria in mitigating drought stress on oak (Quercus brantii Lindl.) seedlings
The successful early establishment of seedlings is a challenging step for the management of forests in semi-arid regions, such as in the oak (Q. brantii) forests in western Iran. To address this challenge, we tested the separate and combined effects of different biofertilizers: we evaluated the influence of the application of biochar and plant growth-promoting rhizobacteria (PGPR) on the growth of oak seedlings subjected to water stress in controlled conditions. Two acorns were sown in a total of 216 pots distributed according to the following treatments: 3 water treatments (100, 75 and 50 % of field capacity), 4 biochar treatments (0, 1, 2 and 3 % of soil weight), 2 PGPR treatments (absence or presence) in 9 replicates. Biochar was derived from mistletoe (Loranthus europaeus), a widespread hemi-parasite plant in the studied oak forests. After emergence, a total of 20 ecophysiological, morphological and growth traits were measured on oak seedlings. We found that the interaction between irrigation, biochar and PGPR significantly influenced the ecophysiological attributes of the seedlings. Comparing application to non-application of PGPR, we found that chlorophyll content, photosynthesis rate and biomass of shoots were respectively increased by 21, 50 and 19 % in the absence of water stress and by 54, 14 and 18 % under severe water stress conditions. Moderate biochar concentrations improved seedling growth and ecophysiological responses whereas the highest concentration of biochar had a detrimental effect. A PLS path model revealed the direct and indirect relationships between the treatments, the seedling morpho-physiological traits and the final variable of interest (total dry biomass). The model explained 78 % of the total variance and showed that the root growth indices (path coefficient = 0.665) had a significant direct effect on oak dry matter whereas this effect was reduced with shoot growth indices. We found that the use of moderate levels of biochar alone or in combination with PGPR can benefit oak seedling development in water-limited conditions but further studies are still needed to test the effectiveness and applicability of these treatments in field conditions.
113. 题目: Regional Sources and Seasonal Variability in Rainwater Dissolved Organic and Inorganic Nitrogen at a Mid-Atlantic, USA Coastal Site
114. 题目: Enhanced MFC sensor performances and extracellular electron transport efficiency mediated by biochar and underlying biochemical mechanisms
To explore the application of biosensor in real-time monitoring of composite heavy metal polluted wastewater in view of the low performance of MFC sensor, this study used sodium alginate to immobilize biochar to the anode of MFC biosensor, and conducted a study on the sensor performance and related biological processes. The results showed that under the optimal HRT conditions, the output power of the MFC-sensor (BC-300) was 0.432 W/m3 after biochar modification, which was much higher than the highest power density of CG and BC-0 of 0.117 and 0.088 W/m3. The correlation coefficient was greater than that of the control group at the plating wastewater concentration of 0.1–1.0 M and had a wider detection range, and the time to recover the output voltage was 1/3 of that of the control group. The biochar significantly promoted the sensitivity, interference resistance, recovery and anti-interference performance of the MFC-sensor. The intrinsic mechanism was that the composition and structure of biochar lead to a 1.53 fold increase in the abundance of electrogenic microorganisms and the abundance of functional genes such as cytochrome c (MtrABC, CymA, Cox, etc.) and flavin (riba, Rib B, gdh, ushA, IDH, etc.) increased by about 1.03–3.20 times, which promoted the shift of electrons from intracellular to extracellular receptors and significantly improved the electron transfer and the energy metabolism efficiency. The results of this study can provide a reference for the application of MFCsensor to the detection of complex heavy metal effluents.
115. 题目: Depth-specific transport of bacteriophages MS2 and ΦX174 in intact soils
Soil geochemical and structural heterogeneities are coupled in influencing the fate and transport of viruses in soil profiles. Only the soil layer at a certain depth, where viruses have least mobility, determines the total flux and distance of virus transport. However, few studies have addressed the dependence of virus transport on soil depths. This dependence is mostly due to the gradients of geochemistry, soil structure, and solution chemistry along the soil profile. We employed intact soil columns (5 cm in length, 4.5 cm in inner diameter) from three depths (5–10 cm, 35–40 cm, and 65–70 cm) to investigate the transport of two very different model viruses: 1) MS2; a hydrophobic, negatively charged, less aggregated phage of E. coli, and 2) ΦX174; a hydrophilic, positively charged (pH=6.58 ± 0.21), highly aggregated phage of E. coli as a function of depth. The breakthrough of both viruses increased with soil depth in both 10 mM and 40 mM NaCl solutions. The mobility of MS2 was greater than ΦX174 at 5–10 cm and 35–40 cm depths, but the mobility of ΦX174 increased much faster than MS2 with soil depth and surpassed MS2 mobility in the soil of 65–70 cm depth. The effect of ionic strength on the mobility of nanosized MS2 decreased with soil depth because of decreased soil organic matter (SOM) content. The decreased SOM lessened ionic strength sensitivity via a hydrophobicity-reduced Lewis acid-base attraction mechanism. In comparison, ΦX174 viruses showed an overall weaker response to ionic strength change since they were aggregated into microsized particles in the experimental solutions and thereby subjected to mechanical straining in the intact soils. The elevated straining effect counteracted the electrostatically facilitated transport of ΦX174. These findings suggest that soil amendments with organic matter might be low cost, effective measures for reducing virus transport through soil profiles.
116. 题目: Removal of Aqueous Eriochrome Blue-Black R by novel Na-Bentonite/Hickory Biochar Composites
Advanced clay sorbents have attracted widespread attentions for applications in environment remediation and pollution control. Here, a facile and environmentally-friendly approach to synthesizing a porous Na-bentonite/hickory-biochar composite sorbent from hickory waste biomass using hand-milling and carbon-bed pyrolysis was investigated. The sorbents, made using a range of clay/biomass ratios and at a range of temperatures, were characterized and examined for their ability to remove Eriochrome blue black R (EBBR) anionic organic dyes from aqueous solution. The composite sorbents showed increased microporosity and O-containing functional groups over the pyrolyzed bentonite control. The composite prepared with 10% biomass by weight, and at 600°C had the greatest EBBR adsorption, and was best fit to Freundlich isotherm and intraparticle diffusion kinetics models. The modeled maximum EBBR sorption capacity of this composite (2020.5 mg g-1, R2 adj = 0.92), which was attributed to the dispersion of bentonite particles over the biochar surface. These results show the bentonite/biochar composite to have great potential for use in environmental remediation applications.
117. 题目: Mechanism of calcium hydroxide-reinforced magnesium-loaded clinoptilolite/phosphoric acid-modified biochar for NH3-N removal from rare earth element tailings wastewater
118. 题目: Permafrost degradation and nitrogen cycling in Arctic rivers: insights from stable nitrogen isotope studies
119. 题目: Temporal and spatial dynamics distribution of organic carbon content of surface soil in coastal wetlands of Yancheng, China from 2000 to 2022 based on Landsat images
To study the dynamic changes of soil organic carbon (SOC) content in coastal wetlands over the past 23 years, we use the third core area of the Dafeng Elk Nature Reserve in Jiangsu Province, China as the study area. A normalized difference soil spectral index (NDSOC), which is directly related to SOC, was constructed by using the spectral reflectance of Landsat images, and six auxiliary environmental variables related to SOC were extracted: surface temperature, surface moisture, soil salinity, the normalized difference vegetation index (NDVI), surface brightness, and soil texture information. The coastal wetland soil surface SOC inversion model was constructed by multiple linear regression, support vector machine, and particle swarm optimization-based random forest regression (PSO-RFR). By using the best inversion model, we obtain the dynamic distribution of soil surface SOC in the third core area of the Dafeng Elk Reserve for the past 23 years. The results indicate (1) that the NDSOC index constructed based on the short-wave infrared (SWIR) bands 1 and 2 of the Landsat images has a strong indication of SOC. Among the extracted auxiliary environmental variables, the NDVI, soil clay content, surface temperature, and soil salinity contribute more strongly to the SOC content of coastal wetlands, which averaged 27.9 %, 24.4 %, 22.1 %, and 18 %, respectively. (2) The PSO-RFR algorithm provided the best simulation of the surface SOC content of coastal wetlands: the model determination coefficient R2 is 0.731, the average fitting root mean square error RMSE is 0.917 g/kg, and the fitting uncertainty standard deviation was 0.362 g/kg. (3) From 2000 to 2022, the organic carbon storage and organic carbon density in the third core area of the Dafeng Elk Reserve gradually increased, the highest value was reached in 2016, they were 4.017 (104 t) and 1.718 kg/cm2, respectively.
120. 题目: Degradation of odorous 2,4,6-trichloroanisole in chlorinated water by UV-LED/chlorination: kinetics and influence factors
2,4,6-Trichloroanisole (2,4,6-TCA) has aroused a special concern for their odor problem and potential threats. In this study, the degradation of 2,4,6-TCA by UV/chlorination with different UV sources was compared, including low-pressure mercury lamp (LPUV, 254 nm) and ultraviolet light-emitting diode (UV-LED, 275 and 285 nm). The maximum removal of 2,4,6-TCA can be achieved by 275-nm UV-LED/chlorination in neutral and alkaline conditions which was 80.0%. The reaction, kinetics, and water matrix parameters on 2,4,6-TCA degradation were also evaluated. During UV-LED (275 nm)/chlorination, 2,4,6-TCA degradation was mainly caused by direct UV photolysis and indirect hydroxyl radical (HO·) oxidation, while reactive chlorine radicals (RCSs) had a negligible contribution. The second-order rate constant between HO· and 2,4,6-TCA was determined as 3.1 × 109 M−1 s−1. Increasing initial chlorine dosage and decreasing 2,4,6-TCA concentration or pH value significantly promoted 2,4,6-TCA degradation during UV/chlorination process. The presence of natural organic matter (NOM) and bicarbonate (HCO3−) can inhibit 2,4,6-TCA degradation, while chloride ion (Cl−) had a negligible effect. The kinetic model for 2,4,6-TCA degradation was established and validated, and the degradation pathways were proposed based on the identified intermediates. Furthermore, UV-LED (275 nm)/chlorination also exhibited a promising effect on 2,4,6-TCA removal in real water, which can be used to control 2,4,6-TCA pollution and odor problems.