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22741. 题目: High-efficiency degradation of organic pollutants with Fe, N co-doped biochar catalysts via persulfate activation
文章编号: N20042503
期刊: Journal of Hazardous Materials
作者: Xiang Li, Yan Jia, Minghua Zhou, Su Xianfa, Jianhui Sun
更新时间: 2020-04-25
摘要:

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 (k_obs) 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.

22742. 题目: The effect of biochar on soil-plant-earthworm-bacteria system in metal(loid) contaminated soil
文章编号: N20042502
期刊: Environmental Pollution
作者: Hong-Tao Wang, Jing Ding, Qiao-Qiao Chi, Gang Li, Qiang Pu, Zu-Fei Xiao, Xi-Mei Xue
更新时间: 2020-04-25
摘要:

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.

22743. 题目: Interactions between the ice algae Fragillariopsis cylindrus and microplastics in sea ice
文章编号: N20042501
期刊: Environment International
作者: Linn Hoffmann, Sarah Lena Eggers, Erika Allhusen, Christian Katlein, Ilka Peeken
更新时间: 2020-04-25
摘要:

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.

22744. 题目: Archaeoanthrosol formation in the Brazilian semiarid
文章编号: N20042428
期刊: Catena
作者: José João Lelis Leal de Souza, Bartolomeu Israel de Souza, Rafael Albuquerque Xavier, Anderson Almeida Pacheco, Luiz Carlos Ruiz Pessenda, Edson dos Santos Brito
更新时间: 2020-04-24
摘要:

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.

22745. 题目: Mass, nutrients and dissolved organic carbon (DOC) lateral transports off northwest Africa during fall 2002 and spring 2003
文章编号: N20042427
期刊: Ocean Science
作者: Nadia Burgoa, Francisco Machín, Ángeles Marrero-Díaz, Ángel Rodríguez-Santana, Antonio Martínez-Marrero, Javier Arístegui, Carlos Manuel Duarte
更新时间: 2020-04-24
摘要: The circulation patterns and the impact of the lateral export of nutrients and organic matter off NW Africa are examined by applying an inverse model to two hydrographic datasets gathered in fall 2002 and spring 2003. These estimates show significant changes in the circulation patterns at central levels from fall to spring, particularly in the southern boundary of the domain related to zonal shifts of the Cape Verde Frontal Zone. Southward transports at the surface and central levels at 26∘ N are 5.6±1.9 Sv in fall and increase to 6.7±1.6 Sv in spring; westward transports at 26∘ W are 6.0±1.8 Sv in fall and weaken to 4.0±1.8 Sv in spring. At 21∘ N a remarkable temporal variability is obtained, with a northward mass transport of 4.4±1.5 Sv in fall and a southward transport of 5.2±1.6 Sv in spring. At intermediate levels important spatiotemporal differences are also observed, and it must be highlighted that a northward net mass transport of 2.0±1.9 Sv is obtained in fall at both the south and north transects. The variability in the circulation patterns is also reflected in lateral transports of inorganic nutrients (SiO2, NO3, PO4) and dissolved organic carbon (DOC). Hence, in fall the area acts as a sink of inorganic nutrients and a source of DOC, while in spring it reverses to a source of inorganic nutrients and a sink of DOC. A comparison between nutrient fluxes from both in situ observations and numerical modeling output is finally addressed.

22746. 题目: Geochemical signatures of transgressive shale intervals from the 811 Ma Fifteenmile Group in Yukon, Canada: Disentangling sedimentary redox cycling from weathering alteration
文章编号: N20042426
期刊: Geochimica et Cosmochimica Acta
作者: Timothy M. Gibson, Marcus Kunzmann, André Poirier, Dirk Schumann, Nicholas J. Tosca, Galen P. Halverson
更新时间: 2020-04-24
摘要:

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 Fe_HR/Fe_T and Fe_T/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 Fe_T/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 Fe_HR/Fe_T 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.

22747. 题目: The contribution of aqueous catechol-silica complexes to silicification during carbonate diagenesis
文章编号: N20042425
期刊: Geochimica et Cosmochimica Acta
作者: S. Escario, M. Nightingale, P. Humez, B.M. Tutolo
更新时间: 2020-04-24
摘要:

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.

22748. 题目: Bradford quantification of Glomalin-Related Soil Protein in coloured extracts of forest soils
文章编号: N20042424
期刊: Geoderma
作者: G. Cissé, M. Essi, M. Nicolas, S. Staunton
更新时间: 2020-04-24
摘要:

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.

22749. 题目: In-situ nitrogen-doped black TiO₂ with enhanced visible-light-driven photocatalytic inactivation of Microcystis aeruginosa cells: synthesization, performance and mechanism
文章编号: N20042423
期刊: Applied Catalysis B: Environmental
作者: Li Zhou, Min Cai, Xu Zhang, Naxin Cui, Guifa Chen, Guo-yan Zou
更新时间: 2020-04-24
摘要:

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.

22750. 题目: Sustainable impact of tartaric acid as electron shuttle on hierarchical iron-incorporated biochar
文章编号: N20042422
期刊: Chemical Engineering Journal
作者: Zhonghao Wan, Yuqing Sun, Daniel C.W. Tsang, Zibo Xu, Eakalak Khan, Shou-Heng Liu, Xinde Cao
更新时间: 2020-04-24
摘要:

Metal-biochar composite is considered as a promising alternative for future carbocatalysis in environmental decontamination. Nevertheless, unavoidable metal leaching impedes its scaling-up application and remains an environmental concern in the present scientific progress. Herein, a hierarchical Fe biochar (Fe/CBC) derived from cellulose was fabricated via a hydrothermal carbonization coupled with microwave irradiation and NH₃ activation. Several exterior organic electron shuttles (i.e., ascorbic acid, oxalic acid, tartaric acid, and hydroquinone) were accommodated onto Fe/CBC to introduce more electroactive functionalities (i.e., C–O and C = O). In particular, comprehensive material characterization was performed to elaborate the physicochemical properties of tartaric acid-treated biochar catalyst (Fe/CBC-TA). Synergies of inherent hierarchical structure, well-developed carbon π-electron network, and accommodated electron shuttle could mitigate the Fe leaching from 2.44 to 0.578 mg L⁻¹ in the peroxymonosulfate (PMS) activation system for catalytic degradation of bisphenol A. Based on the results of scavenging experiments and electron paramagnetic resonance (EPR) analysis, the catalytic mechanisms transformed from a one-phase pathway (mainly ^•OH) for the Fe/CBC system to a two-phase pathway (first phase: ¹O₂; second phase: ^•OH) for the Fe/CBC-TA system. The increased activation energy and improved catalyst recyclability of the Fe/CBC-TA in the redox reaction further pinpointed its environmental sustainability. Overall, this work offers new strategies to fabricate efficient metal-biochar catalyst and insights into its sustainable electrocatalysis.

22751. 题目: Efficient activation of peroxydisulfate (PDS) by rice straw biochar modified by copper oxide (RSBC-CuO) for the degradation of phenacetin (PNT)
文章编号: N20042421
期刊: Chemical Engineering Journal
作者: Wei Li, Baoxia Liu, Zeming Wang, Kexin Wang, Yeqing Lan, Lixiang Zhou
更新时间: 2020-04-24
摘要:

In this study, rice straw biochar modified by copper oxide (RSBC-CuO) was successfully fabricated via a hydrothermal method and used as a catalyst for the degradation of organic pollutants by peroxydisulfate (PDS). RSBC-CuO-activated PDS exhibited an outstanding performance on the decomposition of phenacetin (PNT). Electron paramagnetic resonance (EPR) confirmed that the reactive oxygen species (ROS) included SO₄⁻, OH, O₂⁻ radicals and singlet oxygen (¹O₂), which were in charge of the PNT destruction. Scavenger experiments further conformed that ¹O₂ and O₂⁻ played the crucial role in the PNT removal. RSBC-CuO also displayed an excellent stability and reusability. The rate of PNT removal after four consecutive cycles declined slightly. Furthermore, the combination of RSBC-CuO and PDS possessed a universal degradation potential towards various organic pollutants, and the degradation efficiencies of the pollutants such as paracetamol, aniline, p-chlorobenzoic acid, sulfamethazine and 2,4,6-Trichlorophenol reached a range of 86 to 100% within 10 to 30 min. Thus, it is concluded that RSBC-CuO-activated PDS is a novel and feasible approach to the removal of organic contaminants from aqueous solution.

22752. 题目: Measuring the influence of environmental conditions on dissolved organic matter biodegradability and optical properties: a combined field and laboratory study
文章编号: N20042420
期刊: Biogeochemistry
作者: Maxwell Landsman-Gerjoi, Julia N. Perdrial, Brittany Lancellotti, Erin Seybold, Andrew W. Schroth, Carol Adair, Adam Wymore
更新时间: 2020-04-24
摘要: Fluorescence spectroscopy is a common tool to assess optical dissolved organic matter (DOM) and a number of characteristics, including DOM biodegradability, have been inferred from these analyses. However, recent findings on soil and DOM dynamics emphasize the importance of ecosystem-scale factors, such as physical separation of substrate from soil microbial communities and soil physiochemical cycles driving DOM stability. We apply this principle to soil derived DOM and hypothesize that optical properties can only supply information on biodegradability when evaluated in the larger ecosystem because substrate composition and the activity/abundance of the microbial community ultimately drive DOM degradation. To evaluate biodegradability in this context, we assessed aqueous soil extracts for water extractable organic carbon (WEOC) content, biodegradability, microbial biomass and DOM characteristics using fluorescence spectroscopy across a range of environmental conditions (covariant with season and land use) in northern Vermont, USA. Our results indicate that changes in environmental conditions affect composition, quantity, and biodegradability of DOM. WEOC concentrations were highest in the fall and lowest in the summer, while no significant differences were found between land covers; however, DOM biodegradability was significantly higher in the agricultural site across seasons. Despite a shift in utilized substrate from less aromatic DOM in summer to more aromatic DOM in winter, biodegradability was similar for all seasons. The only exception was cold temperature incubations where microbial activity was depressed, and processing was slowed. These results provide examples on how fluorescence based metrics can be combined with context relevant environmental parameters to evaluate bioavailability in the context of the larger ecosystem.

22753. 题目: Formation of Disinfection Byproducts from Algal Organic Matter Exposed to Monochloramine: Effects of Monochloramine Dosages, pH, and Bromide Concentrations
文章编号: N20042419
期刊: Water, Air, and Soil Pollution
作者: Xin Gu, Yanan Zhou
更新时间: 2020-04-24
摘要: The formation of volatile DBPs and haloacetic acids (HAAs) from algal organic matter (AOM) in different chloramination conditions (i.e., different monochloramine (NH₂Cl) dosages, pH values, and bromide concentrations) was studied. In chloramination of AOM, HAAs were the major DBP species, followed by trihalomethanes (THMs), haloacetonitriles (HANs), and haloketones (HKs). The levels of THMs, HAAs, HKs, and HANs generated in chloramination were 75%, 69%, 68%, and 122% of those in chlorination, respectively. The concentrations of THMs and HAAs both doubled as the NH₂Cl dosage doubled. The proportions of bromodichloromethane and dibromochloromethane in THMs and the proportions of dichloroacetic acid and trichloroacetic acid in HAAs increased with the NH₂Cl dosage. Accelerating the pH value enhanced the formation of THMs, HAAs, and HANs, respectively, and favored the formation of brominated THMs. The HAN species distribution was unaffected by the NH₂Cl dosage and pH. Increasing bromide levels slightly increased the yield of THMs and slightly decreased the yields of HAAs and HKs. The species shift from the chlorinated to the brominated was more significant for THMs and HANs than for HAAs. The THM-BSF and dichloroacetonitrile-BSF values were lower in chloramination than in chlorination. The high pH value and bromide level significantly accelerated the THM-BSFs. The maximum values of THM-BSFs and dichloroacetonitrile-BSF were 0.6 and 0.5.

22754. 题目: Assessing biochar application to immobilize Cd and Pb in a contaminated soil: a field experiment under a cucumber–sweet potato–rape rotation
文章编号: N20042418
期刊: Environmental Geochemistry and Health
作者: Shaojun Jiang, Junguang Liu, Jiachen Wu, Guangling Dai, Dongyang Wei, Yuehong Shu
更新时间: 2020-04-24
摘要: Cd and Pb are common toxic contaminants prevailing in agricultural soils contaminated by mining activities. In this study, biochar was used to stabilize Cd and Pb contaminated soil for safe with three crops rotation condition within one year. Field experiments were carried out to investigate the effect of Litchi branch biochar (BC), pyrolyzed at 600 °C and applied at 4 rates [(0 t ha⁻¹ (T0), 10 t ha⁻¹ (T1), 20 t ha⁻¹ (T2) and 30 t ha⁻¹ (T3)]) on remediation of Cd and Pb in agricultural soil near Dabaoshan Mine in South China under a cucumber–sweet potato–rape rotation. The results showed that the application of BC can significantly increase the pH, cation exchange capacity and soil organic matter. After cultivation of crops, the pH values decrease gradually, with the biggest drop of 0.45 pH units in T3 treatment after rape cultivation. BC application increased the yield of three crops up to onefold to twofold in T3 treatment as compared to the control. The uptake of Cd and Pb in all three crops decreases with the increase in BC doses, which is mainly related to the decrease in bioavailable metals in their respective soil treatments. Under 1-year crops rotation, the remediation ability of BC still remains, while Cd and Pb can exhibit different risk to different crops. The data of this study can provide scientific suggestions for the selection of suitable crops and proper BC amount in remediation of heavy metal contaminated soil.

22755. 题目: Ni(II) Adsorption on Biochars Produced from Different Types of Biomass
文章编号: N20042417
期刊: Water, Air, & Soil Pollution
作者: Rafaila-Nikola Mourgela, Panagiotis Regkouzas, Frantseska-Maria Pellera, Evan Diamadopoulos
更新时间: 2020-04-24
摘要: The objective of this study was to demonstrate biochar's effectiveness on Ni(II) removal from aqueous solutions by adsorption on three different biochars. Three different waste feedstocks, namely sewage sludge, exhausted olive pomace and the organic fraction of municipal solid waste, were used to produce biochar through pyrolysis at 300 °C, under inert conditions. The obtained biochars were characterized regarding their main properties and then evaluated as potential Ni(II) adsorbents. All investigated materials showed high adsorption efficiency in the range of 78–97%, with the biochar derived from SS exhibiting the best results, possibly because of its higher cation exchange capacity. Ni(II) removal rates were higher when the adsorption experiments were conducted at natural pH, while the removal efficiency under adjusted pH (acidic or alkaline) was slightly lower. The pseudo-second-order kinetic model adequately described the adsorption kinetics depicting high correlation coefficients, while the Freundlich adsorption isotherm model was successful in simulating equilibrium of adsorption.

22756. 题目: Arsenic in groundwater in Paraíba do Sul river, Brazil: sources, hydrogeochemistry, and correlation with redox parameters
文章编号: N20042416
期刊: Environmental Earth Sciences
作者: Annaliza Carvalho Meneguelli-Souza, Inácio Abreu Pestana, Lucas Silva Azevedo, Marcelo Gomes de Almeida, Maria da Glória Alves, Douglas Felipe Cordeiro Oliveira, Maurício Oliveira Dupim, Rodrigo Araújo Gonçalves, José Marcus de Oliveira Godoy, Cristina Maria Magalhães de Souza
更新时间: 2020-04-24
摘要: This study assessed the presence of As in wells located near the lower Paraíba do Sul river, southeastern Brazil. Water samples were collected from 19 home wells and wells managed by the utility company in the region in June 2016 and February, May, and August 2017. The metalloid was detected in seven wells (37%). The most abundant ions in the wells were Cl⁻, Na⁺, SO₄²⁻ and Ca²⁺ and the ions with the lowest concentrations were F⁻ and Br⁻. The pH values were approximately 7.0 and redox potential and dissolved O₂ values were typical of reducing environments. Levels of As varied between 0.13 μg L⁻¹ and 38.8 μg L⁻¹, which are above the maximum allowable concentration for human consumption according to Brazilian and international regulations (10 μg L⁻¹). The presence of As in wells correlated positively with levels of sulfate and dissolved organic carbon, and correlated negatively with well depth. The results support that the oxidation of sulfide minerals is the process that favors mobilization of As to the groundwater, due to inputs from erosion and rainwater seepage through the soil. No significant seasonal changes were observed in As levels, with the lowest and highest value observed in August (2.61 µg L⁻¹) and June (10.24 µg L⁻¹), respectively. Principal component analysis revealed positive correlation between As levels and nitrite, and the negative correlation between As levels and redox potential and dissolved oxygen. This suggests that arsenite, which is the most soluble and toxic reduced form As, is the predominant chemical species in wells.

22757. 题目: Spatial distribution, source analysis, and ecological risk assessment of PBDEs in river sediment around Taihu Lake, China
文章编号: N20042415
期刊: Environmental Monitoring and Assessment
作者: Xuyin Yuan, Yimin Wang, Li Tang, Huihua Zhou, Nian Han, Hai Zhu, Minori Uchimiya
更新时间: 2020-04-24
摘要: The distribution and composition of organic pollutants in sediment are affected by the source and regional environment. To understand the characteristics and risk of polybrominated diphenyl ethers (PBDEs) in the area around Taihu Lake, composite sediment samples (n = 41) were collected in rivers around Taihu Lake to explore the level, spatial distribution, and source of PBDEs. The results showed that the most abundant BDE congener in river sediment was BDE209, followed by BDE99 and BDE47, with median values of 48.7, 2.17, and 1.52 ng g⁻¹, respectively. Concentrations of PBDEs in sediments from northern rivers were significantly higher than those from other areas, but the overall risk was at a moderate-lower level compared with research results in other references. Results of principle component analysis (PCA) and source characteristics analysis revealed that most of PBDEs in river sediments around Taihu Lake were mixture of multiple sources, which mainly originated from atmospheric deposition, industrial wastewater, and municipal sewage. TOC showed good correlations with most PBDEs, which implied that PBDE components were influenced by sediment organic matter. Meanwhile, the risk of PBDEs in river sediments in this study area is a moderate-lower level.

22758. 题目: Variation of soil dissolved organic carbon under long-term different fertilizations and its correlation with maize yields
文章编号: N20042414
期刊: Journal of Soils and Sediments
作者: Jia Liu, Xiaofen Chen, Daming Li, Changxu Xu, Meng Wu, Ming Liu, Pengfa Li, Guilong Li, Taolin Zhang, Zhongpei Li
更新时间: 2020-04-24
摘要: Purpose There have been many studies about the effects of long-term fertilizations on crop yields and soil organic carbon. However, little attention has been paid to the response of soil dissolved organic carbon (DOC) to fertilization practices. The aims of this work were to investigate the variations of the content and the chemical composition of soil DOC under long-term different fertilizations and to evaluate their correlations with maize yields. Materials and methods A long-term fertilization experiment under a double maize cropping system was established in 1986 in acidic Ultisols of southern China. Soil samples were collected in April 2014 from the following ten treatments: (1) CK (non-fertilization), (2) N (only N fertilization), (3) P (only P fertilization), (4) K (only K fertilization), (5) NP (N and P fertilization), (6) NK (N and K fertilization), (7) NPK (N, P, and K fertilization), (8) HNPK (double doses of NPK fertilization amount), (9) OM (only organic manure), and (10) NPKM (NPK fertilization plus organic manure). The soil basic chemical properties including the content of DOC were determined. Then, the chemical composition of soil DOC was assessed through three-dimensional excitation-emission matrix (3DEEM) and parallel factor analysis (PARAFAC). Results and discussion The results showed that long-term application of organic manure significantly increased the content of soil DOC and obviously changed the chemical composition of soil DOC. Based on the 3DEEM and PARAFAC, organic manure treatments (OM, NPKM) had higher proportions of tryptophan-like components and lower proportions of tyrosine-like components as compared with other treatments (CK and inorganic fertilizer treatments). For the fluorescence indices, organic manure treatments showed significantly higher humification index (HIX) and lower biological index (BIX) and McKnight index than other treatments. Aggregated boosted trees analysis revealed that the DOC content explained 24.6% of the total variance in maize yields and ranked first among all tested soil chemical properties. Furthermore, all fluorescence properties of DOC were correlated with maize yields, in which the HIX index was the most important factor. Conclusions This research demonstrated that not only the content of DOC but also the chemical composition of DOC in acidic Ultisols were significantly correlated to maize yields. It may be an effective way to improve soil quality and productivity by increasing DOC content and HIX index. From the perspective of soil DOC, our results proved again that application of organic manure could be the most suitable fertilization practice in acidic Ultisols of southern China.

22759. 题目: Improvement on soil structure and water retention after application of industrial organic waste as a crop fertilizer
文章编号: N20042413
期刊: Journal of Soils and Sediments
作者: André C. Auler
更新时间: 2020-04-24
摘要: Purpose Industrial organic waste (IOW) from slaughter and processing of poultry and swine might be potential crop fertilizer. The use of IOW is known to alter the dynamics of soil organic carbon (SOC) and exchangeable cations. However, its effects on soil physical properties and processes are still unknown. The aim of this study was to evaluate the effects of the isolated and combined application of IOW and mineral fertilizers (MF) on SOC pools, structural physical properties, water retention, and some chemical properties under long-term no-tillage system. Materials and methods Treatments applied during 6 years were as follows: control (no fertilizers application) and crop nutrients through MF, IOW, and MF + IOW. We evaluated SOC pools (total, permanganate (POx-C), and hot water extractable (HWE-C)), structural soil physical properties (i.e., porosity and water retention), and exchangeable cation contents at 0–10 and 10–20 cm layers. Results and discussion The HWE-C increased in response to IOW application in relation to the control treatment at the 0–10 cm layer. POx-C with MF was closer to IOW application. However, this SOC pool was more affected at 10–20 cm layer, in which the IOW and MF promoted increases of POx-C in relation to control. Both forms of fertilization increased total porosity and water retention and the highest values were observed for IOW. We observed a high correlation between the increases of labile SOC and the improvement of soil physical conditions. The long-term exclusive MF application induced damages on soil, such as decreases in water retention and availability of nutrients. The results of MF + IOW were closer to those of MF treatment than IOW treatment. Conclusions The IOW evaluated is a suitable fertilization strategy, providing soil quality. But their use must be carried out in isolation or in combinations with mineral fertilizers greater than 50% of the blend. Also, this IOW is harmless to health and hygiene due to its treatment.

22760. 题目: Biochar amendment of stormwater bioretention systems for nitrogen and Escherichia coli removal: Effect of hydraulic loading rates and antecedent dry periods
文章编号: N20042412
期刊: Bioresource Technology
作者: Yeasir A. Rahman, Mahmood H. Nachabe, Sarina J. Ergas
更新时间: 2020-04-24
摘要:

Bioretention systems improve stormwater infiltration and water quality; however, limited total nitrogen (TN) and fecal indicator bacteria (FIB) removal is observed in sand-based bioretention media. In this study, the fate of nitrogen and E. coli in bioretention systems was investigated through batch and column studies using sand media, with and without biochar addition. Variables investigated included biochar characteristics, hydraulic loading rate (HLR) and antecedent dry period (ADP). Total ammonia nitrogen (TAN), dissolved organic carbon (DOC), and E. coli removals were significantly higher in biochar-amended columns due to biochar's high cation exchange capacity and specific surface area. TAN adsorption resulted in increased nitrification during the ADP when aerobic conditions developed. Moisture content data revealed that saturated conditions prevailed toward the bottom of biochar-amended columns for several days, favoring denitrification and TN removal. Biochar amended columns also showed more stable TAN, DOC and E. coli effluent concentrations under varying HLR and ADP.