1. 题目: More soil organic carbon is sequestered through the mycelium‐pathway than through the root‐pathway under nitrogen enrichment in an alpine forest
期刊: Global Change Biology
作者: Xiaomin Zhu, Ziliang Zhang, Qitong Wang, Josep Peñuelas, Jordi Sardans, Hans Lambers, Na Li, Qing Liu, Huajun Yin, Zhanfeng Liu
摘要: Plant roots and associated mycorrhizae exert a large influence on soil carbon (C) cycling. Yet, little was known whether and how roots and ectomycorrhizal extraradical mycelia differentially contribute to soil organic C (SOC) accumulation in alpine forests under increasing nitrogen (N) deposition. Using ingrowth cores, the relative contributions of the root-pathway (RP) (i.e., roots and rhizosphere processes) and mycelium-pathway (MP) (i.e., extraradical mycelia and hyphosphere processes) to SOC accumulation were distinguished and quantified in an ectomycorrhizal-dominated forest receiving chronic N addition (25 kg N ha-1 yr-1). Under the non-N addition, the RP facilitated SOC accumulation, while the MP reduced SOC accumulation. Nitrogen addition enhanced the positive effect of RP on SOC accumulation from +18.02 mg C g-1 to +20.55 mg C g-1 but counteracted the negative effect of MP on SOC accumulation from -5.62 mg C g-1 to -0.57 mg C g-1, as compared to the non-N addition. Compared to the non-N addition, the N-induced SOC accumulation was 1.62~2.21 mg C g-1 and 3.23~4.74 mg C g-1, in the RP and the MP, respectively. The greater contribution of MP to SOC accumulation was mainly attributed to the higher microbial C pump (MCP) efficacy (the proportion of increased microbial residual C to the increased SOC under N addition) in the MP (72.5%) relative to the RP (57%). The higher MCP efficacy in the MP was mainly associated with the higher fungal metabolic activity (i.e., the greater fungal biomass and N-acetyl glucosidase activity) and greater binding efficiency of fungal residual C to mineral surfaces than those of RP. Collectively, our findings highlight the indispensable role of mycelia and hyphosphere processes in the formation and accumulation of stable SOC in the context of increasing N deposition.
2. 题目: Source apportionment and elevational gradient of dissolved organic matter over the Tibetan plateau
作者: Hewen Niu, Shichang Kang, Chandan Sarangi, Guotao Zhang, Mengxue Chen, Yuzhong Zhang, Huili Qin
摘要: Our understanding of water-soluble organic constituents and their transformation in the unique aqueous continuum over cryosphere region is scarce. Here, dissolved organic carbon (DOC), dissolved organic nitrogen (DON), and dissolved total nitrogen (DTN) and water-soluble inorganic ions in multiple water bodies from the eastern Tibetan Plateau (TP) cryosphere are systematically determined from a suite of field campaigns, laboratory experiments, linear regression analysis, and multiple comparisons, etc. We found that the water bodies located at high elevation have much lower DOC contents compared to the samples at lower elevation, there has significant altitude dependence of DOC abundance in water bodies over the study area (elevation range: 1971–4700 m asl). Comparison of optical properties, source apportionment, chemical analysis and model simulation of the water bodies provide evidence that the atmospheric deposition of organic species in high mountains is transported to plateau lakes in the northeast of TP via alpine runoff (45%) and snow/ice meltwater (20%). Further, dominance of anthropogenic activities in lower elevations can contribute (35%) to the observed altitudinal dependency. Thus, this preliminary study represents the first systematic investigation of the transport and cycling of organic carbonaceous matter and nitrogenous matter in eastern TP and warrants more robust in-situ observations and measurements in future in High Mountains of Asia.
3. 题目: N2O and NO production and functional microbes responding to biochar aging process in an intensified vegetable soil
期刊: Environmental Pollution
作者: Xi Zhang, Junqian Zhang, Mengxin Song, Yubing Dong, Zhengqin Xiong
摘要: Vegetable soils with high nitrogen input are hotspots of nitrous oxide (N2O) and nitric oxide (NO), and biochar amended to soil has been documented to effectively decrease N2O and NO emissions. However, the aging effects of biochar on soil N2O and NO production and the relevant mechanisms are not thoroughly understood. A15N tracing microcosm study was conducted to clarify the responses of N2O and NO production pathways to the biochar aging process in vegetable soil. The results showed that autotrophic nitrification was the predominant source of N2O production. Biochar aging increased the O-containing functional groups while lowering the aromaticity and pore size. Fresh biochar enhanced the AOB-amoA gene abundance and obviously stimulated N2O production by 15.5% via autotrophic nitrification and denitrification. In contrast, field-aged biochar markedly weakened autotrophic nitrification and denitrification and thus decreased N2O production by 17.0%, as evidenced by the change in AOB-amoA and nosZI gene abundances. However, the amendment with artificially lab-aged biochar had no effect on N2O production. With the extension of aging time, biochar application reduced the soil NO production dominated by nitrification. Changes in the N2O and NO fluxes were closely associated with soil NH4+-N and NO2−-N contents, indicating that autotrophic nitrification played a critical role in NO production. Overall, our study demonstrated that field-aged biochar suppressed N2O production via autotrophic nitrification and denitrification by regulating associated functional genes, but not for lab-aged biochar or fresh biochar. These findings improved our insights regarding the implications of biochar aging on N2O and NO mitigation in vegetable soils.
4. 题目: Ball milling sulfur-doped nano zero-valent iron @biochar composite for the efficient removal of phosphorus from water: Performance and mechanisms
期刊: Bioresource Technology
作者: Dan Ai, Taiqing Wei, Yang Meng, Xu Chen, Bo Wang
摘要: This study successfully prepared a novel sulfur-doped nano zero-valent iron @biochar (BM-SnZVI@BC) by modifying corn stover biochar with Fe0 and S0 using a mechanical ball milling method for effective phosphorus (P) adsorption in the waterbody. Batch experiments revealed that BM-SnZVI@BC (BC/S0/Fe0=3:1:1) reached a Qmax of 25.00 mg P/g and followed PFO and Langmuir models. This work had shown that electrostatic attraction, surface chemical precipitation, hydrogen bonding, and ligand effects all contributed to P removal. Since the FeS layer mitigated the oxidation-induced surface passivation of nZVI, sulfidation significantly extended the lifetime of BM-SnZVI@BC, removing 84.4% of P even after 60 d aging in air. The regeneration experiments of composites showed that re-ball milling destroyed the surface iron oxide layer to improve the properties of the recovered material. This is an essential step in the design of P-removal agents to implement anti-aging and commercialization of adsorbents for engineering applications.
5. 题目: Enhancement of lead removal from soil by in-situ release of dissolved organic matters from biochar in electrokinetic remediation
期刊: Journal of Cleaner Production
作者: Qiang Liu, Qing Zhang, Shiqi Jiang, Zhongcheng Du, Xiaolei Zhang, Huihui Chen, Weiming Cao, Long D Nghiem, Huu Hao Ngo
摘要: This study investigated the release of dissolved organic matters (DOMs) from biochar under DC electric field and the roles of the released DOMs on the removal of heavy metal lead (Pb) from the soil coupled with electrokinetic (EK) remediation. The fluorescence excitation and emission matrix spectra (EEM) analysis suggested biochar could discharge more DOMs under the DC field, while biochar from 300 °C (B300) could release much more DOMs than biochar obtained under the 500 °C and 700 °C (B500 and B700). The major component of the released DOMs was likely the humic-like substances, which exhibited a strong ability to complex with Pb and extract them from the soil matrix. By using B300 as a permeable reactive barrier (PRB) to combine with EK under 0.96 V cm−1, Pb migration rates in the soil and the global Pb removal were improved by about 2.8-fold and 1.1-fold, respectively. By employing B700 as another PRB, installed close to the cathode of reactor, the migration rate and removal of Pb could be greatly enhanced. This study provides new insights into the biochar application for sustainable EK remediation of the soil contaminated with heavy metal species.
6. 题目: Impact of plant litter on nonprotonated aromatics and aromaticity of organic matter in some Cerrado Ferralsols
作者: Aline A Vasconcelos, Robert L Johnson, Ivan F Souza, Luís F.J. Almeida, Rodrigo N Sousa, Emanuelle M.B. Soares, Klaus Schmidt-Rohr, Ivo R Silva
摘要: In fire-prone ecosystems such as the Brazilian Cerrado, pyrogenic C (PyC) can be a relevant contributor to soil C pools. However, the extent to which increasing additions of fresh plant litter can affect the relative contribution of PyC to soil organic matter (SOM) remains unclear. To address this question, we used a 12-month laboratory incubation experiment arranged according to a complete factorial scheme including: three Ferralsols, two depths i.e. topsoil (0–10 cm) and subsoil horizons (60–100 cm), and two levels of a doubly isotope-labeled (13C and 15N) plant litter (0 and 40 mg g−1 soil), with three blocks as replicates. After the incubation, the samples were physically fractionated to isolate SOM within the particle-size fractions (PSF) greater and smaller than 53 µm. Subsequently, we quantified the amount of litter-derived C and N remaining in both PSF and used hydrofluoric (HF) acid 10% (v/v) to demineralize the PSF smaller than 53 µm, yielding the HF-insoluble SOM. This fraction was evaluated with 13C/15N–nuclear magnetic resonance (NMR) spectroscopy by applying the multiple cross-polarization (multiCP) pulse sequence with magic-angle spinning (MAS), yielding semiquantitative solid-state NMR spectra. Averaged across the Ferralsols, the PSF smaller than 53 µm retained about 22.8% of the C and 32.6% of the N added via plant litter. Our NMR results indicated that the incorporation of litter-C and -N led to an increase in aliphatic C (0–110 ppm) coupled to a marked decrease in aromatic moieties (115–154 ppm), particularly nonprotonated aromatics in subsoil samples. Consequently, there was a significant decrease in the aromaticity of SOM. Therefore, with increasing additions of fresh plant material, soil C dynamics in Cerrado Ferralsols may become less reliant on the relative contribution of nonprotonated aromatics to SOM chemistry.
7. 题目: Pyrolysis of furfural residues: Property and applications of the biochar
期刊: Journal of Environmental Management
作者: Stelgen Inkoua, Chao Li, Huailin Fan, Félix Mérimé Bkangmo Kontchouo, Yifan Sun, Shu Zhang, Xun Hu
摘要: Furfural residue (FR) is a solid waste generated during the production of furfural from corn cobs. The chemical energy and material potential of FR can be potentially recovered via pyrolysis. In this study, the pyrolysis of FR at the temperature ranging from 350 to 650 °C at the varied heating rate was investigated, aiming to understand the characteristics of the pyrolysis products. The results indicate that the organic components of FR tend to be cracked to form biochar and gases as the dominate products, due to the high ash content of FR. The FR-derived bio-oil also contained abundant organics derived from cellulose and lignin. Increasing pyrolysis temperature favored formation of the organics with fused ring structures. Lower heating rate in pyrolysis also formed biochar with higher thermal stability and higher fixed carbon content by enhancing the extent of deoxygenation. Additionally, the transformation of –OH via dehydration, -C-H into = C–H via dehydrogenation, and the cracking of C￼O during carbonization of biochar in the pyrolysis were also observed during pyrolysis of FR. Activation of the FR-derived biochar generated abundant micropores and mesopores, rendering the activated carbon with superior specific capacitance as electrodes of electrocapacitors (329 Fg-1) and the excellent adsorption efficiency of phosphate (up to 98.81%).
8. 题目: Effect of pH on the sorption of dissolved organic carbon derived from six tree species in forest soils
期刊: Ecological Indicators
作者: Dawid Kupka, Piotr Gruba
摘要: Dissolved organic carbon (DOC) is an important component of the total carbon (C) pool in temperate forest soils. The ability of forest soils to sorb DOC is an essential feature in the context of ecosystem changes (such as climate change) and the resulting changes in the C cycle. The aim of this study was to investigate the ability of forest soils with different pH levels to sorb DOC from litter of different forest tree species. To accomplish this, we conducted two laboratory experiments in which the soil differed in the depth from which they were sampled (topsoil vs. subsoil) and the initial DOC content. We modified the soil pH to obtain a range covering most soils in temperate forests (approximately 3.5–8). Soil samples were leached with extracts of similar DOC content obtained from the litter of six main forest-forming tree species in temperate zone. Increased DOC sorption was observed at approximate soil pH levels of 3.5 and 7.5, with the highest sorption capacity occurring at low pH. The DOC sorption capacity was decreasing with consecutive leaching with litter extract. The capacity of DOC sorption also depended on the litter species. In addition, the initial concentration of C in soil had no significant relationship with sorption capacity. Litter species were related to the sorption of released DOC, which was probably linked to the Al content in the litter. The increased DOC sorption at low pH was likely because of dissolved organic matter protonation (saturation of functional groups with H+ ions resulting in proton bridging and van der Waals forces), while Ca2+ ions causing cation bridging, flocculation or non-columbic interactions were likely responsible for the increased sorption at high pH. Our research shed light on the significant effects of soil pH on the stabilization of DOC, as well as the important role and positive influence of Al on DOC sorption by forest soils. Our findings provide new, significant insight by presenting that litter-derived DOC sorption is dependent both on soil pH and litter chemical composition.
9. 题目: Co-pyrolysis of wood chips and bentonite/kaolin: Influence of temperatures and minerals on characteristics and carbon sequestration potential of biochar
期刊: Science of The Total Environment
作者: Fei Wang, Ruilin Zhang, Scott W Donne, Yaser Beyad, Xiangyue Liu, Xiaoyu Duan, Tongsa Yang, Peiyuan Su, Hongwen Sun
摘要: Biochars have been highlighted as a means of carbon sequestration, which is significant for achieving carbon neutrality. Mixtures of wood chips and either bentonite or kaolin were co-pyrolysed at temperatures of 350 °C and 550 °C, and the microstructural characteristics and the carbon sequestration potential of the resultant biochar were explored in the study. The addition of minerals promoted the formation of a stable carbon structure in biochar, especially the proportion of Si￼C bonds in the high-temperature mineral-composited biochar increased by 3.56–3.82 times compared with the original biochar. After bentonite or kaolin was added to wood chips pyrolysed at 550 °C, the carbon loss after H2O2 oxidation was reduced to no more than 19.2%, and the Recalcitrance Index (R50) of biochar increased to no less than 0.89. The combined action of high temperature and minerals promoted the formation of highly aromatic structures of biochar (H:C < 0.4) and reduced the amount of dissolved organic carbon to 4.89 mg g−1. Furthermore, minerals directly covered the surface of biochar, and the content of Si￼C bond increased, thus strengthening the chemical and thermal stability of biochar. However, the addition of minerals had no significant effect on the biological stability of biochar. The study indicates that the pre-pyrolysis mineral addition is an effective way to increase the carbon sequestration potential of biochar.
10. 题目: Comparison of the formation of N-nitrosodimethylamine (NDMA) from algae organic matter by chlor(am)ination and UV irradiation
期刊: Science of The Total Environment
作者: Decai Liu, La Rao, Xiaoyang Shi, Jiayu Du, Chen Chen, Wenjie Sun, Ming-Lai Fu, Baoling Yuan
摘要: Microcystis aeruginosa (M. aeruginosa, blue-green algae) blooms frequently in drinking water reservoirs and subsequently causes the formation of disinfection by-products (DBPs) after disinfection, which may pose a potential health risk. In this study, the formation of N-nitrosodimethylamine (NDMA) was evaluated from algal organic matter (AOM) including extracellular organic matter (EOM) and intracellular organic matter (IOM) during the disinfection process of chlorination, chloramination, or ultraviolet (UV) irradiation. The effects of a variety of factors, including reaction times, disinfectant dosages and pH, on the NDMA formation by three different disinfection methods were investigated. Additionally, this study evaluated the nitrogen sources involved in NDMA formation during chloramination of EOM and IOM using 15N-labeled monochloramine. The results showed that the NDMA formation by three different disinfection methods were ranked in the order of chlorination > UV irradiation ≈ chloramination and the specific yield from EOM was greater than that from IOM regardless of disinfection method. The yields of NDMA firstly increased and then plateaued as time prolonged during the chlorination and chloramination of AOM. Similarly, the NDMA formation from EOM was firstly increased and then remained constant with the increase of the disinfectant dosage, while it was gradually increased for IOM. The solution pH highly influenced the NDMA formation during chlorination and chloramination, while exhibited a little impact under UV irradiation. Moreover, fluorescence excitation-emission (EEM) analysis confirmed that soluble microbial by-product-like (SMPs) in EOM and IOM were the major precursors in algal-derived organic matter that contributed to the NDMA formation. Chloramination of EOM and IOM using isotope 15N-labeled monochloramine indicated that the nitroso group of the formed NDMA originates mainly from EOM and IOM of algal cells.
11. 题目: Assessment of potential biotoxicity induced by biochar-derived dissolved organic matters to biological fermentative H2 production
期刊: Science of The Total Environment
作者: Ji-wen Wu, Shu-zhao Pei, Chun-shuang Zhou, Bing-feng Liu, Guang-li Cao
摘要: Biochar is a widely used antecedent for improving bio‑hydrogen production. However, little is known about the impact of biochar-derived dissolved organic matter (DOM) on the performance of fermentative bio-H2 production. Herein, we evaluated the impact of biochar-derived DOM on the fermentation performance of hydrogen-producing microflora. The pyrolysis temperature of biochar affected the DOM composition, with lower pyrolysis temperatures showing more serious inhibition on H2 accumulation. When biochar was pyrolyzed at 500 °C, DOM prolonged the fermentation period and decreased H2 production from 1330.41 mL L−1 to 1177.05 mL L−1 compared to the control group. The xylose utilization in mixed substrate decreased from 29.72% to 26.41%, which is not favorable for practical applications where lignocellulosic biomass is used as a substrate. Otherwise, DOM caused a 6% reduction in microbial biomass accumulation and less soluble metabolites formation. The potential mechanism of DOM inhibiting bio‑hydrogen production was verified by identifying an increase in reactive oxygen species (ROS) level (178.2%) and the microbial community shifted to containing fewer hydrogen-producing strains. The finding prompts a more precise design of biochar applications in fermentation systems to alleviate the potential hazards and maximum the fermentation performance, not limited to fermentative hydrogen production system.
12. 题目: Insights into the synthesis and application of biochar assisted graphene-based materials in antibiotic remediation
期刊: Journal of Cleaner Production
作者: Aniqa Ashraf, Guijian Liu, Muhammad Arif, Md Manik Mian, Audil Rashid, Balal Yousaf, Muhammad Irfan Khawar, Luqman Riaz, Rabia Safeer
摘要: An increase in antibiotic utilization worldwide has led to serious environmental problems due to their direct and indirect release into waterbodies. The addition of pharmaceutically active compounds to water results in antibiotic-resistant bacteria and genes, which create resistance to the particular antibiotic, requiring the need for a much more powerful one on the next use, trapping the world in a vicious cycle. Therefore, an urgent approach to antibiotic removal from water entities is required. At present, numerous carbonaceous materials have shown promising performance in antibiotic treatments. Among them, graphene and graphene-based nanomaterials (GNMs) are at the top of the list. Despite their promising services in antibiotic remediation, their high production cost limits their usage. This review provided an in-depth insight into low-cost graphene production sources/processes along with powerful shreds of evidence of antibiotic pollution remediation using graphene, GNMs, and their composites. Formulation of graphene biochar composite with enhanced working efficiency along with a critical assessment of graphene and graphene-based materials in antibiotic remediation was presented. While discussing all the remediation mechanisms in detail, this review will provide new research insights by converting low-cost solid waste materials into graphene; and graphene-based nano materials, opening up future possibilities of innovatively engineered complex graphene-biochar composites to tackle organic pollution on a commercial scale.
13. 题目: Optical characterization of dissolved organic matter in Kuroshio-Oyashio confluence region: Implication for water mass mixing
期刊: Deep Sea Research Part I: Oceanographic Research Papers
作者: Yasong Wang, Yinghui Wang, Huangmin Ge, Bilin Liu, Jianqiang Wu, Lulu Han, Yongsheng Liu, Jianchun Yu, Yunping Xu
摘要: Chromophoric dissolved organic matter (CDOM) and fluorescent DOM (FDOM) are important components of DOM and play many important roles in biogeochemical processes. Here, we examined the concentration, composition, and distribution of DOM in waters (0–1000 m depth) from the Kuroshio-Oyashio confluence region (Northwestern Pacific), a key area for ocean carbon cycle and an important fishery. Dissolved organic carbon concentration varied between 30.5 and 78.2 μmol L−1 with a higher level in surface waters. Two humic-like components (C1, C3) and one protein-like component (C2) were identified by fluorescence excitation emission matrices-parallel factor analysis. The C1 and C3 intensity generally increased with depth, and positively correlated with apparent oxygen utilization (p < 0.01), whereas the C2 intensity decreased downward, and negatively correlated with apparent oxygen utilization (p < 0.01), suggesting in-situ production of bio-refractory C1 and C3 during the microbial transformation of labile organic matter (like C2). The C1 intensity was significantly different among three water masses (p < 0.01) that was 11.7 ± 2.5 × 10−3 R.U. for Kuroshio Current, 20.1 ± 1.9 × 10−3 R.U. for Oyashio Current, and 26.1 ± 5.8 × 10−3 R.U. for North Pacific Intermediate Water. The application of three-endmember mixing model based on the C1 intensity and salinity revealed variable contributions of Kuroshio, Oyashio, and North Pacific Intermediate Water that were consistent with the predication from water temperature and salinity. Our study suggests that the optical property of DOM is a useful tracer for water masses in the Kuroshio-Oyashio confluence region, consisting with previous reports for other marine environments.
14. 题目: Effects of landuse change and topography on the quantity and distribution of soil organic carbon stocks on Acrisol catenas in tropical small-scale shade cocoa systems of the Ashanti region of Ghana
作者: Fowzia Adiyah, Erika Michéli, Adam Csorba, Tsedekech Gebremeskel Weldmichael, Csaba Gyuricza, Caleb Melenya Ocansey, Evans Dawoe, Stephen Owusu, Marta Fuchs
摘要: Landuse conversion is the highest contributor to atmospheric CO2 in the tropics. While forest conversion to agriculture results in the depletion of soil organic carbon (SOC), cocoa agroforestry may improve SOC stocks. The aim of our study was to explore the effects of topography and landuse change from forest to cocoa agroforestry on the quantity, quality, and distribution of SOC stocks. A total of 324 soil samples from the upper 0–145 cm were collected from catenas with 3 replicates along 3 hillslope positions: upper hillslope/summit position, middle hillslope/backslope position and lower hillslopes/foot- or toeslope positions. SOC stocks were highest in the upper hillslope positions at the 0–30 and 0–60 cm depths and varied from 42.85 ± 10.91 to 44.04 ± 13.70 Mg C ha−1 (0–30 cm depth) and 57.66 ± 18.80 to 60.32 ± 16.36 Mg C ha−1 (0–60 cm depth) for land use types. Hillslope position (upper, middle or lower) significantly affected humic substances with the topsoil having more humified organic materials in the upper compared to other hillslope positions. Forest conversion to shaded-cocoa had a strong impact on the quality of humic substances. Cocoa agroforestry systems had significantly lower E4:E6 ratios with more labile carbon at the lower slope positions compared to similar positions in forest systems. The most labile and readily available organic molecules (fulvic acids) are under forest systems whereas higher proportion of stabilized less soluble organic molecules (lower E4:E6 ratio) are found in cocoa soils in the form of humic acids. Slope position impacted E4:E6 ratios with lower degree of humification of organic materials in lower hillslope positions across the two landuses. A positive correlation was observed between humic substances and clay content. Our study contributes to the understanding of the influence of topography on SOC quantity and quality in forest and cocoa systems in Ghana.
15. 题目: Effects of different low temperature pretreatments on properties of corn stover biochar for precursors of sulfonated solid acid catalysts
期刊: Bioresource Technology
作者: Tianchi Lin, Fanbin Meng, Min Zhang, Qingyu Liu
摘要: In this study, the effects of different pretreatment methods including phosphoric acid (PA), freeze drying (FD) and phosphoric acid-freeze drying combined (PA-FD) pretreatment on corn stover characteristics and pyrolysis of corn stover samples was investigated. The results demonstrated that the physiochemical properties of biochars varied significantly. In comparison, PA pretreatment could effectively remove a large portion of inorganics and improve the fuel characteristics. PA-CSB-600 had a greater HHV, lower O/C and H/C ratios, and a lower biochar energy yield (Ye), indicating the possibility for an attractive fuel source. PA-FD pretreatment would significantly affected cell volume and caused mechanical damage to corn stover structure. As a sulfonated solid acid catalyst precursor, the results of cellulose catalytic hydrolysis indicated that the density of -SO3H in FD-CSA was much higher than PA-FD-CSA, but lower surface special area. Specifically, PA-FD-CSB prepared at 600°C resulted in the maximum increase of cellulose conversion by 34.7-81.3%.
16. 题目: Biochar enhanced polycyclic aromatic hydrocarbons degradation in soil planted with ryegrass: Bacterial community and degradation gene expression mechanisms
期刊: Science of The Total Environment
作者: Xuyang Zhao, Renhui Miao, Meixia Guo, Xingtian Shang, Yanmei Zhou, Jiangwei Zhu
摘要: Biochar and ryegrass have been used in the remediation of polycyclic aromatic hydrocarbons (PAHs)-contaminated soils; however, the effects of different biochar application levels on the dissipation of PAHs, bacterial communities, and PAH-ring hydroxylating dioxygenase (PAH-RHDα) genes in rhizosphere soil remain unclear. In this study, enzyme activity tests, real-time quantitative polymerase chain reaction (PCR), and high-throughput sequencing were performed to investigate the effects of different proportions of rape straw biochar (1%, 2%, and 4% (w/w)) on the degradation of PAHs, as well as the associated changes in the soil bacterial community and PAH-RHDα gene expression. The results revealed that biochar enhanced the rhizoremediation of PAH-contaminated soil and that 2% biochar-treated rhizosphere soil was the most effective in removing PAHs. Furthermore, urease activity, abundance and activity of total bacteria, and PAH-degrading bacteria were enhanced in soil that was amended with biochar and ryegrass. Additionally, the activity of 16S rDNA and PAH-RHDα gram-negative (GN) genes increased with increasing biochar dosage and had a positive correlation with the removal of PAHs. Biochar changed the rhizosphere soil bacterial composition and α-diversity, and promoted the growth of Pseudomonas and Zeaxanthinibacter. In addition, the relative abundance of Pseudomonas was positively correlated with PAH removal. These findings imply that rape straw biochar can enhance the rhizoremediation of PAH-contaminated soil by changing soil bacterial communities and stimulating the expression of PAH-RHDα GN genes. The 2% of rape straw biochar combined with ryegrass would be an effective method to remediate the PAH-contaminated soil.
17. 题目: Preparation and evaluation of fine-tuned micropore biochar by lignin impregnation for CO2 and VOCs adsorption
期刊: Separation and Purification Technology
作者: Xueyang Zhang, Lingyu Cao, Wei Xiang, Yue Xu, Bin Gao
摘要: The pore structure of adsorbent plays a critical role during the CO2 and volatile organic compounds (VOCs) adsorption. To improve the adsorption performance, fine-tuned micropore biochar was prepared by impregnation using sodium lignosulfonate as precursor. And the impregnated biochar was characterized and used as adsorbent to adsorb CO2 and VOCs (benzene and acetone). The results showed that the specific surface area (SSA) and micropore volume (Vmicropore) of impregnated biochar increased 3.27 and 5.02 times, which enhanced the CO2 adsorption amount obviously (77.02–102.88 mg/g). The pore structure of biochar was critical to CO2 capture, and high SSA, large Vmicropore and narrow aperture were benefits for the adsorption. Both Avrami fractional model and Freundlich model fitted the adsorption better, indicating the CO2 adsorption on impregnated biochar was multilayer adsorption and determined by both physical and chemical mechanisms. The adsorption was overwhelming exothermic process, thus increasing the temperature from 0 ℃ to 65 ℃ would decrease the adsorption amount by 74.22%-79.40%. High reusability (93.98%-98.21%) after 10 times adsorption-desorption cycles acknowledged the biochar was promising CO2 adsorbents. In addition, the impregnated biochar exhibited excellent VOCs adsorption performance, with the adsorption amount being 31.35–61.14 mg/g and 44.67–80.99 mg/g for benzene and acetone, respectively. All the results showed lignin impregnated biochar is a promising adsorbent for CO2 capture and pollution adsorption.
18. 题目: Flag leaf cell wall functional groups and components play a crucial role in the accumulation and translocation of Cd in rice grain via foliage application of humic acid
期刊: Ecotoxicology and Environmental Safety
作者: Xiao Deng, Bin Chen, Yixuan Chen, Lu Jiang, Yumin Hu, Yang Yang, Xiangmin Rong, Liang Peng, Qingru Zeng
摘要: Devising a low-cost and effective strategy to reduce Cd contamination of brown rice is critical to achieve the safe production of rice grain for human consumption. Accordingly, here field experiments were conducted at two sites to evaluate the effects of applying humic acid (HA) to foliage twice, at the booting and full heading stage, on diminishing the translocation of cadmium (Cd) into rice grains. Besides measuring the Cd subcellular distribution in the flag leaf and the polysaccharide composition of the cell wall, the latter’s types and concentrations of functional groups were quantitatively analyzed by potentiometric titration and fitted by a surface complexation model. The results demonstrated that applying HA to leaves not only increased the rice yield but also reduced the Cd concentration in brown rice by 35.48–39.74% when using an application rate of just 600 g/ha. The HA treatment augmented Cd fixation in flag leaves, reduced the Cd translocation to rachis and brown rice, and increased the subcellular distribution of Cd in flag leaf cell wall. Furthermore, the Cd concentration in the pectin and hemicellulose 1 of cell wall increased by 33.00% and 25.73%, respectively. Besides those effects, foliar spraying of HA induced a greater abundance of carboxyl, hydroxyl, and amino groups on the cell wall, allowing for more sites to be involved in the binding of Cd, thereby promoting the immobilization of Cd in the flag leaf, and ultimately reducing the remobilization of Cd into the grain. Thus, foliage application of HA may offer a promising and cost-effective tactic for the remediation and continued use of Cd-contaminated paddy soils. Capsule Foliage application of humic acid promoted the deposition of Cd in the cell wall of rice flag leaf, thereby enhancing the immobilization of Cd and ultimately reducing the remobilization of Cd into the grain
19. 题目: Effects of macrophyte species and biochar on the performance of treatment wetlands for the removal of glyphosate from agricultural runoff
期刊: Science of The Total Environment
作者: Olivier Boucher-Carrier, Jacques Brisson, Khalil Abas, Sung Vo Duy, Sébastien Sauvé, Margit Kõiv-Vainik
摘要: Glyphosate is the most widely used herbicide in the world, and consequently has polluted numerous water bodies through agricultural runoff. Treatment wetlands (TWs) have shown great promise for mitigating such pesticide contamination. The objectives of our study were to determine the effects of adding biochar to subsurface flow TW substrate, and to evaluate the performance of three North American macrophyte species (Phragmites australis subsp. americanus, Scirpus cyperinus and Sporobolus michauxianus) for removal of glyphosate. A synthetic agricultural runoff comprising 50 μg/L of glyphosate was applied to water-saturated TW mesocosms with mature vegetation during a 5.5-week period. Average removal efficiency, calculated on a mass balance basis, reached 78 and 82% for mesocosms with biochar (without and with plants, respectively), and 54 to 76% for those with macrophytes. Sporobolus michauxianus showed a lower evapotranspiration rate and less anoxic conditions in the lower part of the substrate, which resulted in lower overall removal performance. Aminomethylphosphonic acid (AMPA), the main toxic metabolite of glyphosate, was detected in all mesocosms, but at higher levels in planted ones. Results show that both the sorption capacity of biochar and the biodegradation processes associated with macrophytes contribute to glyphosate removal in TWs. Additionally, our results suggest that species selection is important to enhance favorable conditions and maximize removal of targeted pollutants.
20. 题目: Avermectin Toxicity to Benthic Invertebrates is Modified by Sediment Organic Carbon and Chemical Residence Time
期刊: Environmental Toxicology and Chemistry
作者: Ruben Jacova, Christopher Kennedy
摘要: Chemicals used in sea lice management strategies in salmonid aquaculture include the avermectin class of compounds that can accumulate and persist in the sediments underneath salmon farms and directly impact nontarget benthic fauna. The effects of sediment organic carbon (OC) content and chemical residence time (CRT) on the lethal and sublethal toxicity of emamectin benzoate (EB; formulation: Slice®) and ivermectin (IVM; purified) and a combination of both were examined in two benthic invertebrates, the amphipod Eohaustorius estuarius and the polychaete Neanthes virens. In both species, increased sediment OC content significantly reduced lethal toxicity, modulation that was more pronounced for IVM and combination exposures. At a CRT of 4 months, lethal toxicity was reduced in E. estuarius but was unaffected in N. virens. Sublethal toxicity in N. virens (burrowing behavior) was modulated by sediment OC and CRT in a similar manner to the trend in lethal toxicity. Inconsistencies in behaviour (phototaxis) in E. estuarius made conclusions regarding toxicity modification by sediment OC or CRT inconclusive. This research indicates that environmental factors including sediment organic carbon content and the time compounds reside in sediments are important modifiers of chemotherapeutant toxicity in nontarget benthic species and should be considered when regulatory decisions regarding their use are made.