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24281. 题目: The fate and impact of TCC in nitrifying cultures Triclocarban (TCC) is a highly effective antibacterial agent, which is widely used in a variety of applications and present at significant levels (e.g., 760 μg/L) in wastewater worldwide. However, the interaction between TCC and nitrifiers, important microbial cultures in wastewater treatment plants, has not been documented. This work therefore aimed to evaluate the fate of TCC in a nitrifying culture and its impact on nitrifiers in four long-term nitrifiers-rich reactors, which received synthetic wastewater containing 0, 0.1, 1, or 5 mg/L TCC. Experimental results showed that 36.7%–50.7% of wastewater TCC was removed by nitrifying cultures in stable operation. Mass balance analysis revealed that the removal of TCC was mainly achieved through adsorption rather than biodegradation. Adsorption kinetic analysis indicated that inhomogeneous multilayer adsorption was responsible for the removal while fourier transform infrared spectroscopy indicated that several functional groups such as hydroxyl, amide and polysaccharide seemed to be the main adsorption sites. The adsorbed TCC significantly deteriorated settleability and performance of nitrifying cultures. With an increase of influent TCC from 0 to 5 mg/L, reactor volatile suspended solids and effluent nitrate decreased from 1200 ± 90 mg/L and 300.81 ± 7.52 mg/L to 880 ± 80 and 7.35 ± 4.62 mg/L while effluent ammonium and nitrite increased from 0.41 ± 0.03 and 0.45 ± 0.23 mg/L to104.65 ± 3.46 and 182.06 ± 7.54 mg/L, respectively. TCC increased the extracellular polymeric substances of nitrifying cultures, inhibited the specific activities of nitrifiers, and altered the abundance of nitrifiers especially Nitrospira sp.. In particular, TCC at environmentally relevant concentration (i.e., 0.1 mg/L) significantly inhibited NOB activity and reduced NOB population. | |||||
24282. 题目: Kinetics of the reaction between hydrogen peroxide and aqueous iodine: Implications for technical and natural aquatic systems Oxidative treatment of iodide-containing waters can lead to a formation of potentially toxic iodinated disinfection byproducts (I-DBPs). Iodide (I−) is easily oxidized to HOI by various oxidation processes and its reaction with dissolved organic matter (DOM) can produce I-DBPs. Hydrogen peroxide (H2O2) plays a key role in minimizing the formation of I-DBPs by reduction of HOI during H2O2-based advanced oxidation processes or water treatment based on peracetic acid or ferrate(VI). To assess the importance of these reactions, second order rate constants for the reaction of HOI with H2O2 were determined in the pH range of 4.0–12.0. H2O2 showed considerable reactivity with HOI near neutral pH (kapp = 9.8 × 103 and 6.3 × 104 M−1s−1 at pH 7.1 and 8.0, respectively). The species-specific second order rate constants for the reactions of H2O2 with HOI, HO2− with HOI, and HO2− with OI− were determined as kH2O2+HOI = 29 ± 5.2 M−1s−1, kHO2-+HOI = (3.1 ± 0.3) × 108 M−1s−1, and kHO2-+OI− = (6.4 ± 1.4) × 107 M−1s−1, respectively. The activation energy for the reaction between HOI and H2O2 was determined to be Ea = 34 kJ mol−1. The effect of buffer types (phosphate, acetate, and borate) and their concentrations was also investigated. Phosphate and acetate buffers significantly increased the rate of the H2O2–HOI reaction at pH 7.3 and 4.7, respectively, whereas the effect of borate was moderate. It could be demonstrated, that the formation of iodophenols from phenol as a model for I-DBPs formation was significantly reduced by the addition of H2O2 to HOI- and phenol-containing solutions. During water treatment with the O3/H2O2 process or peracetic acid in the presence of I−, O3 and peracetic acid will be consumed by a catalytic oxidation of I− due to the fast reduction of HOI by H2O2. The O3 deposition on the ocean surface may also be influenced by the presence of H2O2, which leads to a catalytic consumption of O3 by I−. | |||||
24283. 题目: Enhancing biochar redox properties through feedstock selection, metal preloading and post-pyrolysis treatments There is growing evidence on the importance of the redox properties of biochar for many environmental applications. However, its variability and the difficulty in controlling its redox properties could be delaying the use of biochar in those areas that involve the exchange of electrons, like microbial fuel cells or contaminant degradation related to microbial electron shuttling. To help with these issues, we produced a wide range of biochars showing different redox capacities through a variety of strategies. These include optimizing production and processing parameters, feedstock selection, preloading biomass with redox-active metals and post-pyrolysis treatments. A modified Hummer's method was the most efficient treatment, increasing the electron donating capacity from 0.244 mmol e−/gbiochar to 0.590 mmol e−/gbiochar and the electron accepting capacity from 0.169 mmol e−/gbiochar to 0.645 mmol e−/gbiochar. The characterization of the phases responsible for the redox properties, mainly surface functional groups, radicals and redox-active metals, allowed us to better understand the changes caused to biochar by the different strategies. It revealed that the most important approach to enhance redox properties is to increase the number of C–OH and CO groups in biochar, while the methods that use redox-active metals showed higher than predicted electron donating capacities. We also measured other attributes such as surface area, pH and conductivity, with a focus on their relationship with the redox properties. By selecting the appropriate production and modification methods, we were able to produce a balanced biochar with acceptable conductivity (1.34 mS/cm) and electron exchange capacity (0.418 mmol e−/gbiochar), even though these properties usually have an inverse relationship. This work opens the possibility for the production of designer biochars with tailored properties optimized for specific applications. | |||||
24284. 题目: Assessing the value of BGC Argo profiles versus ocean colour observations for biogeochemical model optimization in the Gulf of Mexico | |||||
24285. 题目: The Effect of Filtration with Natural Esker Sand on the Removal of Organic Carbon and Suspended Solids from the Effluent of Experimental Recirculating Aquaculture Systems | |||||
24286. 题目: Green manure incorporation with reductions in chemical fertilizer inputs improves rice yield and soil organic matter accumulation | |||||
24287. 题目: Characterization of the fate and changes of post-irradiance fluorescence signal of filtered anthropogenic effluent dissolved organic matter from wastewater treatment plant in the coastal zone of Gapeau river | |||||
24288. 题目: Speciation of carboxylic components in humic-like substances (HULIS) and source apportionment of HULIS in ambient fine aerosols (PM2.5) collected in Hong Kong | |||||
24289. 题目: Different adsorption behaviors and mechanisms of a novel amino-functionalized hydrothermal biochar for hexavalent chromium and pentavalent antimony A novel amino-functionalized hydrothermal biochar modified with nitric acid and nicotinamide (NMSH) was prepared and applied to remove heavy metal in different systems. The study of batch adsorption found that NMSH had different adsorption behaviors for Cr(VI) and Sb(V), and different concentrations of heavy metal ions exhibited different coadsorption behaviors in mixed system. NMSH had great anti-interference ability to coexisting inorganic ion and humic substance. The maximum adsorption capacity of NMSH was 132.74 mg/g for Cr(VI), and 241.92 mg/g for Sb(V). Moreover, different interfering ions and matter had different effects on adsorption. The mechanism study found that the adsorption mechanism of NMSH involved multiple interactions, and the mechanisms were different. Some O-containing functional groups of NMSH could reduce Cr(VI) to Cr(III), but not Sb(V). NMSH had great removal efficiency and reusability performance, which suggested that NMSH had prospects for practical wastewater treatment. | |||||
24290. 题目: Impacts of biochar concentration on the growth performance of a leafy vegetable in a tropical city and its global warming potential Urban farming has been gaining popularity but the poor urban soil quality has raised concern regarding soil productivity. Biochar generated from waste wood has been widely applied as a soil conditioner, but few studies investigated its effects when used in high concentrations on urban soil. In this study, the effects of biochar on the growth of the leafy vegetable, xiao bai cai (Brassica rapa Cultivar Group Pak Choi Green-petioled Form) were investigated with its concentrations in urban soil varying from 0 to 100% (v/v). The results demonstrated that the 30% biochar and soil mixture (v/v) was best in terms of fresh weight, dry weight and leaf number gain over those of the control (0% biochar). Analysis of the growing medium showed that by increasing the biochar concentrations, available nitrate and potassium as well as cation exchange capacity increased accordingly, while available phosphate decreased. A life cycle assessment showed that the global warming potential could be reduced when applying waste wood-generated biochar as an urban soil amendment for vegetable production. | |||||
24291. 题目: Black carbon transport between Santiago de Chile and glaciers in the Andes Mountains Near Santiago de Chile and towards the Andes Mountains there are several areas sensitive to contamination, such as, the Natural Sanctuary Yerba Loca, National Park Rio Clarillo, several glaciers and the Farellones ski resort. The health of the glaciers is very important, because a large fraction of the water supply of Santiago is provided by them. To study the influence of Santiago's contamination on the glaciers, a black carbon monitoring campaign was performed from December 2014 (summer) until July 2015 (winter). Four monitors were placed between the city and the glaciers in the mountain along with meteorological stations. An analysis of the measurements indicates a direct transport of black carbon between Santiago de Chile and the Andes Mountains with a travel time of about 11 h in summer and 9 h in winter. Black carbon concentration at the mountain (La Parva) is higher in summer and lower in winter, a trend that is opposite to any other city in Chile. This is the only town in Chile in which transport, not local emissions, is mostly responsible for the BC observed. The fraction of BC in La Parva compared to Las Condes in the eastern part of Santiago changes from 14% in December to 2% in July. Model simulations of black carbon using high resolution meteorological data generated by a regional climate model confirms the difference in summertime and wintertime transport of black carbon from Santiago to La Parva. In December (summer) emissions from Santiago are estimated to contribute with 51% to the concentrations in La Parva while nearby sources from mining activities and long distance transport from other sources in central Chile contributes with 37 and 12% respectively. In July (winter) simulated contributions are dominated by long range transport from other sources with a 50% contribution while simulated contributions from sources in Santiago and from mining are both 25%. The contribution from mining activities is uncertain due to inaccuracies in simulated wind speed and direction in the mountains and too coarse model resolution and therefore warrants further investigation. | |||||
24292. 题目: High-efficiency degradation of organic pollutants with Fe, N co-doped biochar catalysts via persulfate activation In this study, the Fe, N co-doped biochar (Fe-N-BC) was prepared by pyrolyzing wheat straw, urea and iron salts and used to activate persulfate (peroxydisulfate, PS) for organic contaminant degradation. Iron oxide doping not only introduced magnetism into the biochar for easy separation, but also influenced its catalytic ability for PS activation. In the Fe-N-BC/PS system, almost all acid orange (AO7) was removed within 90 min with an apparent rate constant (kobs) of 0.114 min-1, which was almost 37 times larger than that of pure N-BC (0.003 min−1). Factors influencing the removal of AO7 were investigated, including PS concentration, catalyst dosage, and initial pH. The Fe-N-BC/PS system had high removal efficiencies for various organic contaminants and showed high resistance to inorganic anions in aquatic environments. The radical quenching studies, electron paramagnetic resonance (EPR) measurements, and electrochemical analyses verified that the mechanism of AO7 degradation in the Fe-N-BC/PS system included both radical and non-radical pathways involving the generation of •OH, SO4−•, O2−•, 1O2, and electron transfer. Additionally, persistent free radicals (PFRs) on the catalysts also related to their catalytic efficiencies. These results demonstrated that the Fe-N-BC/PS system had the potential for wastewater treatment applications. | |||||
24293. 题目: The effect of biochar on soil-plant-earthworm-bacteria system in metal(loid) contaminated soil Increasing biochar is applied to the metal(loid) contaminated soil. However, effects of biochar on the soil-plant-earthworm-bacteria ecosystem, especially on the gut microbes of soil animals, remain largely unknown and require further research. Here, sewage sludge biochar (SSBC) and rice straw biochar (RSBC) were used in metal(loid) contaminated soils to investigate the available metal(loid) change in soils and the impact on the metal(loid) bioaccumulation in the plant and earthworm. Moreover, effects of biochar amendments on the gut bacteria of earthworms were determined by using high throughput sequencing. Our results showed that RSBC amendments had a significant suppression on the availability of cadmium, but significantly increased arsenic availability in soils (P < 0.05). Compared with the control, the significant reduction of arsenic and cadmium accumulation was observed in plant with biochar amendments. High metal(loid) concentrations were observed in the body tissues of earthworms, in which the highest bioaccumulation factor of cadmium was 18.12 in Metaphire. californica. The earthworm gut bacteria, with high abundances of Firmicutes (39.36%), Actinobacteria (23.69%) and Proteobacteria (13.02%), was significantly different from the microbe from the soil. RSBC had more significant effect on the bacterial community of earthworm gut than SSBC. Taken together, this work indicated thatbiochar amendments could decrease concentrations of arsenic and cadmium in plant, reduce the potential risk of metal(loid)s into the food chain, and shed light on the biogeochemical behaviour of biochar in the soil-plant-earthworm-bacteria ecosystems. | |||||
24294. 题目: Interactions between the ice algae Fragillariopsis cylindrus and microplastics in sea ice High concentrations of microplastics have been found in sea ice but the mechanisms by which they get captured into the ice and which role ice algae might play in this process remain unknown. Similarly, we do not know how the presence of microplastics might impact the colonization of sea ice by ice algae. To estimate the ecological impact of microplastics for Polar ecosystems, it is essential to understand their behaviour during ice formation and possible interactions with organisms inhabiting sea ice. In this study we tested the interaction between the ice algae Fragillariopsis cylindrus and microplastic beads with and without sea ice present and, in a third experiment, during the process of ice formation. With sea ice present, we found significantly less algae cells in the ice when incubated together with microplastics compared to the incubation without microplastics. However, during ice formation, the presence of microplastics did not impact the colonisation of the ice by F. cylindrus cells. Further, we observed a strong correlation between salinity and the relative amount of beads in the water and ice. With increasing salinity of the water, the relative amount of beads in the water decreased significantly. At the same time, the relative amount of beads in the ice increased significantly with increasing ice salinity. Both processes were not influenced by the presence of F. cylindrus. Also, we found indications that the presence of algae can affect the amount of microplastic beads sticking to the container walls. This could indicate that EPS produced by ice algae plays a significant role in surface binding properties of microplastics. Overall, our results highlight that the interactions between algae and microplastics have an influence on the uptake of microplastics into sea ice with possible implications for the sea ice food web. | |||||
24295. 题目: Archaeoanthrosol formation in the Brazilian semiarid Multiple waves of dispersion populated South America throughout the late Pleistocene and early Holocene. The oldest rock art and artifacts in Caatinga are dated from 10,000 BP. Besides that, there is no register of ancient activities in soils in Caatinga. Four pedons were taken, described and classified in sites with a high number of artifacts littering the surface and/or rock art. Five more pedons were described to represent soil without anthropic influence. Soils are shallow and transition between horizons was predominantly clear or abrupt. Anthrosols in Caatinga have value and chroma similar to the anthropic horizons described in Amazonian dark earths. The pedons are strongly acid to slightly alkaline and predominantly have base saturation above 50% in all horizons. Anthrosols in Caatinga have up to 6 and 544 times, respectively, more soil organic carbon and phosphorus compared to adjacent soils without anthropic influence. Besides illite and kaolinite, apatite and calcite compose the clay and silt fractions and confirm the human influence in soil formation. Radiocarbon and thermoluminescence dating indicate that Anthrosols in Caatinga are contemporaneous to the majority of Amazonian dark earths. | |||||
24296. 题目: Mass, nutrients and dissolved organic carbon (DOC) lateral transports off northwest Africa during fall 2002 and spring 2003 | |||||
24297. 题目: Geochemical signatures of transgressive shale intervals from the 811 Ma Fifteenmile Group in Yukon, Canada: Disentangling sedimentary redox cycling from weathering alteration Despite iron and trace element proxies informing much of our insight into Earth's oxygenation history, the processes that controlled their accumulation and distribution in ancient sedimentary environments are not fully understood. Furthermore, deciphering between primary, depositional signals and oxidative weathering alteration poses a substantial challenge to reconstructing Earth's redox history using its sedimentary record. Here, we present a multi-proxy geochemical investigation of three transgressive shale intervals from the ca. 811 Ma Reefal assemblage (upper Fifteenmile Group) in Yukon, Canada to help resolve these issues. Systematic stratigraphic trends from low to high FeHR/FeT and FeT/Al compositions across shale intervals represent shoaling of a discrete redoxcline that separated oxygenated surface waters from anoxic, ferruginous deep waters during marine transgression. In some cases, these trends are followed by a symmetric fall, which represents a full transgressive-regressive cycle of the redoxcline. The high proportion of glauconite to total illite indicate short-term oscillating redox conditions as the redoxcline migrated across the sediment-water interface during relative sea-level rise. These conditions invigorated dissimilatory iron reduction (DIR) within anoxic sediment pore waters, which released Fe(II) into the overlying water column where it was oxidized to iron oxy(hydr)oxide and shuttled downslope. High rates of DIR within sediment replete with highly reactive iron oxy(hydr)oxide and organic matter removed isotopically light, bio-available iron, rendering the residual sediment depleted in FeT/Al relative to the detrital baseline and enriched in 56Fe. The low iron content of the detrital flux to the basin (Fe/Al ∼ 0.3) rendered the sediment susceptible to changes in its bulk δ56Fe composition by modification of its authigenic components alone and enabled fractionation from DIR to drive bulk-rock δ56Fe values up to 0.8‰. Anomalously high concentrations of redox-sensitive elements in three samples (up to 5792 ppm Cr, 586 ppm Mn, 726 ppm Mo, and 3509 ppm Ni) and their relative distribution patterns show similarities to co-enrichment due to particulate shuttling within a weakly restricted basin. However, SEM-EDS element maps and large-area BSE image mosaics show the remains of framboidal pyrite ghosts with secondary enrichment of redox-sensitive elements. Thus, these geochemical trends in redox-sensitive trace metals most likely reflect mobilization and re-accumulation following pyrite dissolution during outcrop weathering. The low primary pyrite content and local transformation of pyrite iron to iron oxy(hdr)oxide suggest that δ56Fe and FeHR/FeT data were unaltered despite indications of pyrite weathering. Ultimately, this dataset elucidates key aspects of sedimentary redox cycling directly preceding evolutionary milestones and a major perturbation to the global carbon cycle and also provides a template for evaluating the effects of outcrop weathering on commonly used sedimentary redox proxies. | |||||
24298. 题目: The contribution of aqueous catechol-silica complexes to silicification during carbonate diagenesis Pore-filling and carbonate-replacing silica is exceedingly common in carbonates, but the fundamental geochemical mechanisms that drive these silicification reactions during diagenesis remain poorly understood. An existing model has proposed that carbonate silicification proceeds through an interface-coupled dissolution-precipitation reaction, but it lacks a mechanism that enables pore fluids to reach the requisite level of supersaturation with respect to silica to allow nucleation and growth. Here, we present a sequence of batch experiments ranging in duration from 7 to 49 days designed to test the hypothesis that these reactions are facilitated by the formation and destruction of organo-silica complexes during diagenesis. Our results illustrate that the stability of organo-silica complexes is dependent upon the concentration of organic molecules in solution, as well as pH, salinity, and solution redox state. Together, these results allow us to present the following scheme for organo-silica complex mediation of silicification reactions: Firstly, the breakdown of organic matter in the presence of siliceous material creates organo-silica complexes, leading to silica-enriched pore fluids, a process which is enhanced by the anoxic conditions accompanying sediment burial. Then, as environmental conditions evolve (fO2, salinity, light, fCO2, pH…), the stability of the organo-silica complexes diminishes, and the organo-silica complexes break down. Simultaneously, the pore fluids become intensely silica-supersaturated, in direct proportion to the amount of organic material remaining in solution. The resulting supersaturation drives carbonate silicification via the precipitation of silica minerals, a process which is aided by the presence of silica nuclei (such as sponge spicules). This study contributes new data and a conceptual model that will aid in the ongoing quest to understand carbonate silicification reactions and their potential applications in hydrocarbon exploitation and geologic CO2 storage. Moreover, it helps to explain the common association between silica precipitates and organic mineral in the sedimentary rock record. | |||||
24299. 题目: Bradford quantification of Glomalin-Related Soil Protein in coloured extracts of forest soils Glomalin-related soil protein (GRSP) is thought to represent a fraction of recalcitrant organic matter in soil. But it is recognized that the autoclaved-citrate extraction procedure causes the co-extraction of humic substances which interfere (directly and indirectly) with the Bradford colorimetric assay. The aim of this work was to propose a reliable quantification method of GRSP from forest soil, very rich in organic matter and therefore in colour. We estimated the quantities of GRSP in the topsoil (0–10 cm) of 102 French forests using five methods: i) direct calibration, reasoned dilution with colour correction, ii) direct calibration, reasoned dilution but no colour correction, iii) direct calibration, 1:2 dilution, no colour correction, iv) indirect calibration and v) dilution method. Our results concur that the interference caused by the co-extracted compounds is not related simply to either the colour of the extracts or total soil organic matter content. These findings suggest that for improved accuracy of GRSP estimates using the Bradford method, extracts should be diluted, and the pH-specific absorbance of coloured extracts should be subtracted. | |||||
24300. 题目: In-situ nitrogen-doped black TiO2 with enhanced visible-light-driven photocatalytic inactivation of Microcystis aeruginosa cells: synthesization, performance and mechanism A series of nitrogen-doped black TiO2 nanocatalysts were successfully synthesized by a one-step method. It is novel to find that calcination in an N2 atmosphere completed N doping and oxygen vacancies production simultaneously. In contrast, the urea addition as N precursor inhibited the nitrogen incorporation and the oxygen vacancies production. However, it is the sample using urea as N precursor that had the higher visible-light absorption, the narrower bandgap, the more efficient excited charges separation and higher degradation efficiency for removing chlorophyll-a in Microcystis aeruginosa algae cells. Mechanism exploration indicated that the intermediate energy states existed within the bandgap of TiO2, and·O2- and·OH were the dominant radicals responsible for algae cell damage and organic matter degradation. This research will provide additional insight into the roles of N precursors and a calcining atmosphere to improve the photocatalytic activity of nitrogen-doped black TiO2 for algae inactivation and metabolites degradation. | |||||
