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25241. 题目: Biochar exerts negative effects on soil fauna across multiple trophic levels in a cultivated acidic soil
文章编号: N20020110
期刊: Biology and Fertility of Soils
作者: Ting Liu, Lihua Yang, Zhengkun Hu, Jingrong Xue, Yanyan Lu, Xiaoyun Chen, Bryan S. Griffiths, Joann K. Whalen, Manqiang Liu
更新时间: 2020-02-01
摘要: Biochar application is perceived as a promising agricultural technology, but risk evaluation on the soil ecosystem has focused exclusively on soil microbes, whether microfood-web is likewise influenced by biochar remains unclear. We carried out a pot experiment planted with rapeseed for 2 years to test how biochar application (0, 20, 60 t ha⁻¹), with or without nitrogen (N) fertilizer (0, 60, 120 t ha⁻¹), affected soil microbes and microfauna (protists and nematodes). We observed that a high amount of biochar (60 t ha⁻¹) increased crop productivity, microbial activity, and biomass carbon (C) and N, as well as the abundance of flagellates (protists), but decreased the abundances of bacterivorous, fungivorous, and herbivorous nematodes as well as the abundance of amoebae (protists). High biochar addition rates also shifted nematode community composition toward a fungivore dominance, and favored herbivores by decreasing the ratio of microbivorous to herbivorous nematodes. However, N fertilizer and its interaction with biochar generally had no effect on microbial activity and biomass as well as the abundance of protist and nematode. A structural equation model revealed that the effects of biochar on soil biota were largely direct, which might depend on biochar properties (e.g., pore size and alkalinity), whereas indirect effects, mediated by crop, soil pH, soil moisture, and polycyclic aromatic hydrocarbon (PAH) concentration, generally had no effect on soil biota. We conclude that biochar is a suitable soil amendment for increasing crop growth, but its detrimental effect on multitrophic levels of soil fauna calls for an identification of the optimal application rate and size fraction that could minimize potential negative effects on certain soil communities.

25242. 题目: Comparison of soil microbial community between planted woodland and natural grass vegetation on the Loess Plateau
文章编号: N20020109
期刊: Forest Ecology and Management
作者: Yang Yang, Huan Cheng, Liangxu Liu, Yanxing Dou, Shaoshan An
更新时间: 2020-02-01
摘要: Soil microorganisms play an important role in regulating subsurface ecological processes. Planted woodland and natural grass vegetation are the main vegetation restoration strategies for preventing soil erosion on the Loess Plateau of China. However, the response of soil microbial community and diversity to planted woodland and natural grass vegetation is largely unknown in this region. Here, we investigated soil microbial community and diversity using high-throughput sequencing approaches in planted woodland and natural grass vegetation. We found a disproportionate influence of planted woodland and natural grass vegetation on soil microbial diversity, and there was an increase of soil fungal diversity and a decrease of soil bacterial diversity in planted woodland. Both soil pH and soil organic carbon (SOC) were highly related to soil microbial diversity in planted woodland and natural grass vegetation. Moreover, we found the complex interaction networks of soil fungal community in planted woodland. Meanwhile, there were the higher total path coefficients of soil fungal diversity and the lower total path coefficients of bacterial diversity in planted woodland according to SEM (structural equation modeling). Besides, planted woodland explained more variation to soil fungal diversity and natural grass vegetation explained more variation to soil bacterial diversity, indicating that soil fungal diversity was more easily affected by planted woodland, while soil bacterial diversity was more easily affected by natural grass vegetation. To enhance the balance of soil microbial diversity, we suggested that both planted woodland and natural grass vegetation are needed in this region, highlighting the necessity of understanding soil microbial ecology to manage vegetation restoration on the Loess Plateau of China.

25243. 题目: Adsorption and reduction of Cr(VI) by hydroxylated multiwalled carbon nanotubes: effects of humic acid and surfactants
文章编号: N20020108
期刊: Environmental Science and Pollution Research
作者: Yu Huang, Ke Song, Wei Luo, Jiewen Yang
更新时间: 2020-02-01
摘要: The present study investigated the impacts of humic acid (HA) and surfactants (SDBS and CTAB), which were ubiquitously found in the aquatic environments, on the removal of Cr(VI) by the hydroxylated MWCNTs-OH. The results showed that MWCNTs-OH could remove Cr(VI) from aqueous solution via adsorption coupled with reduction, and the kinetics followed the pseudo-first-order model with the rate of 3.5 × 10⁻³ h⁻¹. In the presence of anionic SDBS, the removal percentage of Cr(VI) was greatly inhibited because the hydrophobic interaction and π-π interaction between SDBS and MWCNTs-OH surfaces not only decreased the adsorption sites for Cr(VI) but also made the surfaces more negatively charged. On the contrary, the existence of cationic CTAB could lead to the surfaces more positively charged, which consequently enhance the electrostatic attraction between Cr(VI) and the surfaces as well as the removal of Cr(VI). Noticeably, the presence of HA could promote the removal of Cr(VI), which was attributed to the reduction of Cr(VI) by the adsorbed HA. The ESR spectra indicated the existence of π-type radicals in HA structure and conduction electrons in MWCNTs-OH, and then the π-π interaction between MWCNTs-OH and adsorbed HA possibly increase the electron-donating ability of HA. Moreover, the promotive effect of HA could be enhanced with the addition of Ca²⁺. This study was helpful for us to understand the role of MWCNTs-OH in controlling the fate of Cr(VI) when HA and surfactants were present.

25244. 题目: Rhizobium improves nutritive suitability and tolerance of Phaseolus vulgaris to Colletotrichum lindemuthianum by boosting organic nitrogen content
文章编号: N20020107
期刊: Applied Soil Ecology
作者: Edwin M. Karoney, Dennis M.W. Ochieno, Danstone L. Baraza, Edward K. Muge, Evans N. Nyaboga, Victoria Naluyange
更新时间: 2020-02-01
摘要: Symbiotic nitrogen fixing Rhizobium species have been reported to trigger induced resistance reactions that are inhibitive to aboveground antagonists. We tested the hypothesis that root infection by nitrogen-fixing Rhizobium triggers enzyme-mediated induced resistance reactions, which lead to the production of defensive compounds that suppress aboveground colonization by foliar pests. An experiment was conducted using common bean Phaseolus vulgaris, comprising of factorial treatments of Rhizobium inoculation (with or without), C. lindemuthianum (with or without) and soil type (solarized and non-solarized). Anthracnose disease incidence was higher in plants under dual inoculation with C. lindemuthianum and Rhizobium than in plants inoculated with C. lindemuthianum alone (p < 0.05). Concentrations of N-based compounds in the form of total protein and the enzymes, peroxidase, ascorbate peroxidase and lipid peroxidase were higher in rhizobial plants, while that of catalase enzyme and the C-based compounds namely flavonoids, tannins and phenols were lower. Plant size and growth duration were not different between the treatments (p > 0.05). Soil pH, organic carbon and the concentration of nutrients (N, P, Na, Ca, Mg, Zn, Cu) in solarized soil were higher than in non-solarized soil, while Fe and K were lower. There was no evidence to support induced resistance since anthracnose disease was high in Rhizobium inoculated plants. High disease incidence without reduction in plant growth can be interpreted as host plant tolerance. In conclusion, Rhizobium infection of common bean enhances the production of N-based nutritive compounds, while limiting the production of C-based organic compounds associated with plant resistance, thereby promoting host plant suitability to C. lindemuthianum, and possibly enhancing host plant tolerance to the pathogen.

25245. 题目: Visualizing electron storage capacity distribution in biochar through silver tagging
文章编号: N20020106
期刊: Chemosphere
作者: Danhui Xin, Thomas Barkley, Pei C. Chiu
更新时间: 2020-02-01
摘要: Electron storage capacity (ESC) is the capacity of a black carbon to store and reversibly donate and accept electrons in redox processes. Electrochemical and chemical analyses have shown the ESC of black carbon (e.g., plant-based biochars) was on the order of a few mmol/g. However, it remains unknown where ESC is located. The spatial distribution of ESC is important because it controls the bioaccessibility of ESC and the rates of biochar redox reactions. Here we used silver to tag the ESC of a wood-derived biochar. Ag⁺ was allowed to diffuse into the pores of reduced biochar at a constant pH. Up to 2.49 mmol Ag⁺/g biochar (corresponding to 62% of its ESC) was reduced to Ag^o nanoparticles (nAg), which served as an ESC marker and was visualized by electron microscopy. Abundant and dense nAg were observed on the biochar surface. In addition, microtomed samples showed ubiquitous and well-dispersed nAg in the interior of biochar, which explains pore diffusion-limited redox reactions and the partial bioaccessibility of its ESC. In addition to probing ESC distribution in black carbon, this method represents a new, ESC-based approach to incorporate large quantities of Ag and other redox-active elements into carbon media for potential environmental applications.
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25246. 题目: Effects of nano-Fe₃O₄-modified biochar on iron plaque formation and Cd accumulation in rice (Oryza sativa L.)
文章编号: N20020105
期刊: Environmental Pollution
作者: Jing-Yi Zhang, Hang Zhou, Jiao-Feng Gu, Fang Huang, Wen-Jun Yang, Shi-Long Wang, Teng-Yue Yuan, Bo-Han Liao
更新时间: 2020-02-01
摘要: Nano-Fe₃O₄-modified biochar (BC–Fe) was prepared by the coprecipitation of nano-Fe₃O₄ on a rice husk biochar surface. The effects of BC-Fe on cadmium (Cd) bioavailability in soil and on Cd accumulation and translocation in rice (Oryza sativa L. cv. ‘H You 518’) were investigated in a pot experiment with 7 application rates (0.05–1.6%, w/w). BC-Fe increased the biomass of the rice plants except for the roots and affected the concentration and accumulation of Cd and Fe in the plants. The Cd concentrations of brown rice were significantly decreased by 48.9%, 35.6%, and 46.5% by the 0.05%, 0.2%, and 0.4% BC-Fe treatments, respectively. Soil cation exchange capacity (CEC) increased by 9.4%–164.1% in response to the application of BC-Fe (0.05–1.6%), while the soil Cd availability decreased by 6.81%–25.0%. However, 0.8–1.6% BC-Fe treatments promoted Cd transport to leaves, which could increase the risk of Cd accumulation in brown rice. Furthermore, BC-Fe application promoted the formation of iron plaque and enhanced the root interception of Cd. The formation of iron plaque reduced the toxicity of Cd to rice roots, but this barrier effect was limited and had an interval threshold (DCB-Fe: 22.5–27.3 g·kg⁻¹) under BC-Fe treatments.
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25247. 题目: Importance of the structure and micropores of sedimentary organic matter in the sorption of phenanthrene and nonylphenol
文章编号: N20020104
期刊: Environmental Pollution
作者: Decheng Xu, Shujie Hu, Yongqiang Xiong, Yu Yang, Yong Ran
更新时间: 2020-02-01
摘要: The demineralized fraction (DM), lipid-free fraction (LF), nonhydrolyzable organic carbon fraction (NHC), and black carbon (BC) were isolated from five marine surface sediments, and they were characterized by elemental analysis as well as CO₂ and N₂ adsorption techniques, respectively. The NHC fractions were characterized using advanced solid-state ¹³C nuclear magnetic resonance (NMR) and x-ray photoelectron spectroscopy (XPS). Then, the sorption isotherms of phenanthrene (Phen) and nonylphenol (NP) on all of the samples were investigated by a batch technique. The CO₂ micropore volumes were corrected for the outer specific surface areas (SSAs) by using the N₂-SSA. Significant correlations between the micropore-filling volumes of Phen and NP and the micropore volumes suggested that the micropore-filling mechanism dominated the Phen and NP sorption. Meanwhile, the (O + N)/C atomic ratios were negatively and significantly correlated with the sorption capacities of Phen and NP, indicating that the sedimentary organic matter (SOM) polarity also played a significant role in the sorption process. In addition, a strong linear correlation was demonstrated between the aromatic C and the sorption capacity of Phen for the NHC fractions. This study demonstrates the importance of the micropores, polarity, and aromaticity on the sorption processes of Phen and NP in the sediments.
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25248. 题目: Time-dependent evolution of Zn(II) fractions in soils remediated by wheat straw biochar
文章编号: N20020103
期刊: Science of The Total Environment
作者: Ping Wu, Ting-Ting Qian, Ting-Ting Fan, Ying Zhang, Cun Liu, Dong-Mei Zhou, Yu-Jun Wang
更新时间: 2020-02-01
摘要: Biochar is a cost-effective and multifunctional carbon material, which can be used to immobilize heavy metal (HM) in soil. To date, the immobilization of different HM by various biochars are well-studied, however, little is known about the release condition of the immobilized HM. As the released HM may bring a threat to the soil environment, it is critical to understand the release pattern of biochar-sorbed HM in soil. Herein, six wheat straw-derived biochars (WBs) pyrolyzed under different temperature and duration time were loaded with zinc(Zn (II)), and the evolution of Zn(II) fractions in soils remediated by WBs over time was investigated by Community Bureau of Reference (BCR) three-step sequential extraction method. The main Zn(II) species sorbed on WBs were the Zn(II) sorbed on the acidic functional groups of WB and that sorbed on WB surface via electrostatic interaction. Generally, Zn(II) sorbed on high-temperature WB was more mobile than that sorbed on low-temperature WB. In the red soil, the soluble and exchangeable Zn(II) (i.e., Zn(II) in Fraction 1) in WB was inclined to transform to organic matter associated-Zn(II) (i.e., Zn(II) in Fraction 3) and residual Zn(II) (i.e., Zn(II) in Fraction 4). In the yellow-brown soil, the soluble and exchangeable Zn(II) in WB was prone to convert into amorphous Fe/Mn oxide associated-Zn(II) (i.e., Zn(II) in Fraction 2) and residual Zn(II). These results imply that Zn(II) sorbed by WB has the risk to be released into the soil environment, and WB produced at low temperature are more suitable to remediate soils with low/neutral pH.
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25249. 题目: Electromagnetic fields for biofouling mitigation in reclaimed water distribution systems
文章编号: N20020102
期刊: Water Research
作者: Yang Xiao, Youngwoo Seo, Yufei Lin, Lei Li, Tahir Muhammad, Changjian Ma, Yunkai Li
更新时间: 2020-02-01
摘要: Biofouling is ubiquitous in reclaimed water distribution systems and causes various industrial, economical, and health issues. This paper investigated the anti-biofouling efficacy of electromagnetic fields (EMFs) for agricultural emitters used for two types of reclaimed water. 16S rRNA gene sequencing and X-ray diffraction were applied to determine the microbial communities and mineral compositions in biofilm. The obtained results revealed that EMF treatment significantly changed the bacterial communities and reduced their diversities in biofilm by affecting water quality parameters. Network analysis results indicated that EMFs were detrimental to the co-occurrence patterns of mutualistic relationships among bacterial species, destroyed the connectivity and complexity of the networks, and inhibited biofilm formation [decreased total biomass and extracellular polymeric substance (EPS) content]. EMF treatment could also decrease the deposition of mineral precipitates, reducing the carbonate and silicate content in biofilm. The decrease of EPS content appeared to reduce biofilm-induced mineral crystallization, while the ion precipitations accelerated by EMFs caused an erosive effect on biofilm. The results demonstrated that EMF treatment is an effective, chemical-free, and anti-biofouling treatment method with great potential for biofouling control in reclaimed water distribution systems.
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25250. 题目: Mitigation of methylmercury production in eutrophic waters by interfacial oxygen nanobubbles
文章编号: N20020101
期刊: Water Research
作者: Xiaonan Ji, Chengbin Liu, Meiyi Zhang, Yongguang Yin, Gang Pan
更新时间: 2020-02-01
摘要: In mercury (Hg)-polluted eutrophic waters, algal blooms are likely to aggravate methylmercury (MeHg) production by causing intensified hypoxia and enriching organic matter at the sediment-water interface. The technology of interfacial oxygen (O₂) nanobubbles is proven to alleviate hypoxia and may have potential to mitigate the risks of MeHg formation. In this study, incubation column experiments were performed using sediment and overlying water samples collected from the Baihua Reservoir (China), which is currently suffering from co-contamination of Hg and eutrophication. The results indicated that after the application of O₂ nanobubbles, the %MeHg (ratio of MeHg to total Hg) in the overlying water and surface sediment decreased by up to 76% and 56% respectively. In addition, the MeHg concentrations decreased from 0.54 ± 0.15 to 0.17 ± 0.01 ng L⁻¹ in the overlying water and from 56.61 ± 9.23 to 25.48 ± 4.08 ng g⁻¹ in the surface sediment. The decline could be attributed to the alleviation of anoxia and the decrease of labile organic matter and bioavailable Hg. In addition, hgcA gene abundances in the overlying water and surface sediment decreased by up to 69% and 44% after the addition of O₂ nanobubbles, as is consistent with MeHg occurrence in such areas. Accordingly, this work proposed a promising strategy of using interfacial oxygen nanobubbles to alleviate the potentially enhanced MeHg production during algal bloom outbreaks in Hg-polluted eutrophic waters.
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25251. 题目: Effect of Chloride and Suwannee River Fulvic Acid on Cu Speciation: Implications to Cu Redox Transformations in Simulated Natural Waters
文章编号: N20013119
期刊: Environmental Science & Technology
作者: Guowei Xing, Shikha Garg, Christopher J. Miller, A. Ninh Pham, T. David Waite
更新时间: 2020-01-31
摘要: Copper is a critical trace nutrient and, at higher concentrations, a toxicant in natural waters, with the relative rates of transformation between the Cu(I) and Cu(II) oxidation states being key to its speciation, bioavailability, and toxicity. While the influence of chloride (Cl−) and natural organic matter on Cu speciation and associated redox transformations has been studied separately, their combined influence on Cu speciation and Cu redox transformations has not been examined. As such, in this study, we investigate the impact of Cl– and Suwannee River fulvic acid (SRFA) on Cu(II) reduction and Cu(I) oxidation kinetics at pH 8.2. SRFA plays a dual role in providing Cu(II) reducing moieties as well as Cu ligating sites. Our results indicate that the SRFA-bound Cu(II) is less reactive than the inorganic Cu(II), and the SRFA-bound Cu(I) being much more rapidly oxidized than the inorganic Cu(I). The presence of Cl– weakens Cu(II) binding by SRFA, thereby increasing the reactivity of Cu(II). Similarly, weakening of Cu(I) binding by SRFA and concomitant binding of Cu(I) by Cl– stabilizes Cu(I). Our results further show that continuous formation of hydrogen peroxide occurs in the presence of Cu(II), SRFA, and Cl– in air-saturated solution with the presence of H2O2 enhancing the dynamic nature of the system.

25252. 题目: Generation and properties of aqu/nC 60 : the combined effects of humic acid, sunlight, and agitation intensity
文章编号: N20013118
期刊: Environmental Science and Pollution Research
作者: Xueyao Li, Guanghui Ding, Jing Zhang, Yingying Wang, Wanran Li, Chunchao Wang, Ruijuan Li, Zhanning Yang
更新时间: 2020-01-31
摘要: Once released into natural water, the environmental behavior and fate of C₆₀ could inevitably been affected by humic acid (HA), sunlight, and hydrodynamic conditions. However, the combined effects of these factors are not so clear. Therefore, in the present study, effects of HA, sunlight, and agitation intensity on generation and properties of aqu/nC₆₀ were investigated. The results indicated that HA could increase the concentration of aqu/nC₆₀ mainly through the steric hindrance effect. The higher agitation intensity led to higher concentrations of aqu/nC₆₀ and more efficient steric stabilization was formed by HA. Sunlight irradiation promoted the surface oxidization and consequently enhanced the dispersion of C₆₀. The relative order of the influence on the UV/vis concentration was sunlight > agitation intensity > HA. In addition, HA might not always enhance the dispersion of aqu/nC₆₀ due to light screening/ROS scavenging, over-coating, or chain-like bridging mechanism. Therefore, evaluating the environmental behavior and fate of C₆₀ should take these factors into account together.

25253. 题目: Enhanced reduction of sulfate and chromium under sulfate-reducing condition by synergism between extracellular polymeric substances and graphene oxide
文章编号: N20013117
期刊: Environmental Research
作者: Jia Yan, Weizhuo Ye, Xiaoshan Liang, Siji Wang, Jiehui Xie, Kengqiang Zhong, Min Bao, Jinbin Yang, Huijun Wen, Shugeng Li, Yongheng Chen, Ji-Dong Gu, Hongguo Zhang
更新时间: 2020-01-31
摘要: Microbial reduction of sulfate and metal were simultaneously enhanced in the presence of graphene oxide (GO)-like nanomaterials, however, the mechanism remained unclear. In this study, bio-reduction of Cr was compared between free-living bacterium BY7 and immobilized BY7 (BY-rGO) on reduced GO particles. The role of extracellular polymeric substances (EPS) and rGO material on reduction of sulfate and Cr was investigated. Cr(VI) was reduced to Cr(III) and elemental Cr by BY-rGO particles up to 51% and 28%, respectively. EPS produced by the bacterium BY7 mainly consisted of proteins, polysaccharides, nucleic acids and humic substances. Concentration of EPS was sharply increased (about 54%) with the addition of graphene oxide, while the composition of EPS components was strongly affected by the exposure to Cr. By removing surface EPS without breaking the cells, reduction activities of sulfate and chromium by both BY-rGO particles and free-living BY7 cells were decreased. In contrast, reduction of sulfate and Cr by the free-living BY7 cells was enhanced with external addition of extracted EPS. Based on electrochemical analysis, the reduction peak indicating enhanced electron transfer was lost after removing EPS. Moreover, the contribution of each EPS fractions on sulfate and Cr reduction followed an order of polysaccharides > proteins > humic substances. Therefore, microbial sulfate and Cr reduction processes in the presence of BY-rGO particles were enhanced by the increasing amounts of EPS, which likely mediated electron transfer during sulfate and Cr reduction, and relieved bacteria from metal toxicity. Nevertheless, the presence of rGO was crucially important for elemental Cr production under sulfate-reducing condition, which might contribute to lowering electric potential or reducing activation energy for Cr(III) reduction. This work provided direct evidences for enhancing sulfate and Cr reduction activities by supplement of EPS as an additive to increase treatment efficiency in environmental bioremediation.
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25254. 题目: Evidence for high organic carbon export to the early Cambrian seafloor
文章编号: N20013116
期刊: Geochimica et Cosmochimica Acta
作者: Meng Cheng, Chao Li, Chengsheng Jin, Haiyang Wang, Thomas J. Algeo, Timothy W. Lyons, Feifei Zhang, Ariel Anbar
更新时间: 2020-01-31
摘要: Oxygenation of the early Cambrian ocean is commonly ascribed to high organic export to the sediment due to the rise of algae and filter-feeding animals, but direct evidence of elevated export fluxes has been lacking to date. Here, we report an integrated proxy dataset (U-Mo isotopes, Fe speciation, and major and trace elements) for lower Cambrian black shales at Yuanjia on the Yangtze Platform (South China). These shales are characterized by high iron speciation ratios and Mo and U enrichments, indicating persistently euxinic water conditions during their deposition, but a broad range of δ⁹⁸Mo values (–0.10‰ to +1.94‰) implies strongly variable watermass sulfidity. High and variable nutrient element (Cu, Zn, Ni, Cd) enrichments at Yuanjia are consistent with elevated and variable organic productivity and export fluxes from the euphotic zone to the early Cambrian seafloor. The Yuanjia shales also exhibit super-heavy δ²³⁸U values (to +0.84‰) that cannot be explained by U reduction in sediment porewaters. We hypothesize that these values record a U reduction process within the water column, where U isotope fractionation can be much larger than in sediment porewaters. Such processes may have operated within a benthic organic flocculent layer at the sediment-water interface, a feature that is characteristic of high productivity systems with anoxic bottom waters. Furthermore, the coupling between δ²³⁸U, nutrient elements, and δ⁹⁸Mo suggests that elevated productivity levels were driven likely by episodic upwelling in early Cambrian oceans, supplying abundant nutrients for productivity and influencing H₂S concentrations in the water column. These observations, along with high organic carbon accumulation rates (5600 mg cm^-2 kyr^-1), are direct evidence of high organic export fluxes to the early Cambrian seafloor, thus providing key support for the hypothesis that enhanced organic export and burial triggered a major atmospheric-oceanic oxygenation event that stimulated the subsequent explosion of Cambrian life.

25255. 题目: Genomic and geochemical identification of the long-chain alkenone producers in the estuarine Lake Takahoko, Japan: Implications for temperature reconstructions
文章编号: N20013115
期刊: Organic Geochemistry
作者: Hiroto Kajita, Hideto Nakamura, Naohiko Ohkouchi, Naomi Harada, Miyako Sato, Shun Tokioka, Hodaka Kawahata
更新时间: 2020-01-31
摘要: Identifying the lacustrine haptophyte species that produce long-chain alkenones (LCAs) is essential for using alkenone unsaturation ratios to create lake water temperature reconstructions. We discovered LCAs in the brackish Lake Takahoko in northern Japan. The identity of LCA-producing species was investigated using 18S ribosomal DNA (rDNA) and organic geochemical analysis. Two distinct genetic groups, termed as Tak-A and Tak-B, were identified within the Group II haptophyte phylotype. Tak-A was closely related to Hap-A, which was obtained from Lake George, USA; and Tak-B was identified as Isochrysis galbana. Because Hap-A and Isochrysis galbana have similar temperature calibrations, Tak-A and Tak-B were also expected to share similar calibrations. Therefore, the changes of their relative abundances in the lake should not significantly disturb paleotemperature reconstructions. The alkenone temperature recorded in the surface sediment corresponded to the lake temperature in early to late summer. This is likely related to the haptophyte bloom season in Lake Takahoko suggesting that this lake may be a viable location for creating an lacustrine alkenone paleotemperature record.

25256. 题目: Glucose fermentation with biochar amended consortium: Sequential fermentations
文章编号: N20013114
期刊: Bioresource Technology
作者: Jia-Hsun Lu, Chuan Chen, Chihpin Huang, Shao-Yuan Leu, Duu-Jong Lee
更新时间: 2020-01-31
摘要: The aim of this work was to study sequential batch fermentation of glucose with a biological consortium amended with nine different biochars or with an activated carbon. The glucose fermentation was enhanced by carbon amendment, with activated carbon being more effective than biochars as cell carriers and electron conductors between functional species. The volatile fatty acid distributions were shifted in the consumption of the produced H₂ and CO₂. The types of biochars were irrelevant to glucose glycolysis and the subsequent H₂ and CO₂ consumption reactions. Biofilm growth affects the detailed mechanisms occurred in fermentation broth to the yielded volatile fatty acid distributions.

25257. 题目: Magnetic activated biochar nanocomposites derived from wakame and its application in methylene blue adsorption
文章编号: N20013113
期刊: Bioresource Technology
作者: Xinxin Yao, Lili Ji, Jian Guo, Shaoliang Ge, Wencheng Lu, Lu Cai, Yaning Wang, Wendong Song, Hailong Zhang
更新时间: 2020-01-31
摘要: In this work, magnetic wakame biochar nanocomposites for the first time had been synthesized to investigate their adsorption to methylene blue dye. As-prepared magnetic biochar samples were obtained by the impregnation method to load nickel on wakame biochar via one-step carbonization with activation agent KOH at 800 °C. The prepared samples were characterized by BET, XRD, FTIR, Raman, SEM, TEM and so on. The results exhibited that the maximum adsorption capacity of BW(Ni)0.5 to methylene blue could reach 479.49 mg/g at 20 °C. The adsorption behavior was more suitable for Langmuir isotherm equation and the kinetic data were most consistent with the pseudo second-order model. And also, the adsorption reaction was a spontaneous and endothermic process. After five cycles, it was found that BW(Ni)0.5 had a high adsorption capacity for methylene blue (117.58 mg/g). This study demonstrated that wakame biochar could have great potential in dye wastewater treatment.
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25258. 题目: Engineered rice-straw biochar catalysts for the production of value-added chemicals from furan
文章编号: N20013112
期刊: Chemical Engineering Journal
作者: Younghyun Lee, Sung Woo Lee, Yiu Fai Tsang, Yong Tae Kim, Jechan Lee
更新时间: 2020-01-31
摘要: In this study, biochars produced in two different atmospheres were used as catalysts for the valorization of furan, which derives from the hemicellulosic component of waste biomass. The biochars were produced from rice straw via pyrolysis in either an N₂ or a CO₂ environment (RSB-N₂ or RSB-CO₂) to modify their surface area and porosity. The biochars were then employed as a catalyst to support a bifunctional Ru–ReO_x catalyst. The biochar-supported Ru–ReO_x catalysts (Ru–ReO_x/RSB) were compared to a conventional activated charcoal (AC)-supported Ru–ReO_x catalyst (Ru–ReO_x/AC). The biochar-supported catalysts exhibited differences in reducibility and contained a different form of Re species compared to the AC-supported catalyst, which was attributed to the presence of alkali metal (e.g., potassium) in the biochar catalysts. The reducibility and metal dispersion on the support were also strongly associated with the atmosphere under which the biochar was produced. In particular, the Ru–ReO_x/RSB-CO₂ catalyst consumed 24% more hydrogen than did the Ru–ReO_x/RSB-N₂ catalyst within a temperature range of 250 to 560 °C. The biochar-supported catalysts had 12 times fewer surface metal sites than did the AC-supported catalyst due to their lower surface area. The reaction rate on a per-site basis for the conversion of furan to tetrahydrofuran and 1,4-butanediol was also measured for the catalysts. The Ru–ReO_x/RSB-N₂ catalyst was twice as active as the Ru–ReO_x/RSB-CO₂ catalyst and three times more active than the Ru–ReO_x/AC catalyst. This study thus proposes a straightforward strategy for modifying the catalytic properties of biochar catalysts and suggests a new application of biochar in the production of value-added chemicals from biomass and waste. The results also highlight the potential of biochar as a replacement for conventional catalysts in biorefineries.

25259. 题目: Critical study of crop-derived biochars for soil amendment and pharmaceutical ecotoxicity reduction
文章编号: N20013111
期刊: Chemosphere
作者: Magda Caban, Agnieszka Folentarska, Hanna Lis, Paulina Kobylis, Aleksandra Bielicka-Giełdoń, Jolanta Kumirska, Wojciech Ciesielski, Piotr Stepnowski
更新时间: 2020-01-31
摘要: In this study, biochars (BCs) produced from crops (straw and seeds) were tested for the applicability as additive to soils. The effect on pH, water capacity and cation exchange capacity of soil were tested. The ability for the sorption of pharmaceuticals (beta-blockers, anti-inflammatory drugs, sulfonamides, 17α-ethinylestradiol, carbamazepine, caffeine) using the batch sorption test was performed, and the effect of water pH was investigated. In addition, the metals removed from the biochar was analyzed as a potential toxicity factor. The mechanism of adsorption (Langmuir, Freundlich) was tested for sulfadimetoxine. The effect of the rye-derived biochar on water cress germination and the reduction of the sulfonamides toxicity to this plant was tested. The advantages of crop-derived biochar application to different soils (sand soil, clay soil and reference soil) was presented. It was found that tested BCs effectively increase the water capacity of soils, especially sand type soil, but in the same time it had increase the pH of pure-buffering soils. The driving force of pharmaceutical sorption was its ionization form - the highest sorption occurs for cations, medium for neutral forms, while the lowest sorption for anions. The opposite situation have been noted for desorption from biochar. The washing of biochars increases sorption for the neutral and anionic species, but not for the cations. The application of biochars into the soils can from one site protect the plants from toxic impact of sulfonamides, but from the other hamper the root prolongation by the pH increase.
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25260. 题目: Stabilization process and potential of agro-industrial waste on Pb-Contaminated soil around Pb–Zn mining
文章编号: N20013110
期刊: Environmental Pollution
作者: Yan Zhang, Xuemei Wang, Hongbing Ji
更新时间: 2020-01-31
摘要: Sawdust wastes were used as precursors to prepare adsorbents by combustion and pyrolysis for experimental and mechanism studies and determine the potential of biomass extracted from agro-industrial residues for Pb-polluted soil remediation. Pot experiments were conducted on contaminated soils near Pb–Zn mining with sawdust ash (SA) and sawdust biochar (SB) in different proportions and dosage ratios. Studies have indicated that the application of biomass materials can enhance the adsorption, complexation and precipitation of Pb cations in soil and reduce the mobility of Pb. The concentrations of SPLP-Pb and DTPA-extractable Pb in amended soils were the lowest under 1% 1:2 and 5% 1:1 treatment, respectively. Results of fraction extraction and XANES analysis showed that the materials change the main forms of Pb in soil. Moreover, the binding behavior of Pb with organic matter increases the proportion of Pb (Ac)₂, leading to the transformation of high toxicity Pb-compounds into precipitates and complexes. The remediation methods of 2% 1:2 and 5% 1:2 were better than those of other methods in stabilizing Pb in soil. This study indicated that heat-treated sawdust can be used for Pb-polluted soil remediation, which is a type of environmental remediation measure with considerable ecological potential.
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